Biorefinery of food and beverage waste valorisation for sugar syrups production: Techno-economic assessment

Accepted Manuscript Title: Your article is registered as ¨ belonging to the Special Issue/Collection entitled APCChE ¨. If this is NOT correct and your article is a regular item or belongs to a different Special Issue please contact [email protected] immediately prior to returning your corrections.–>Biorefinery of food and beverage waste valorisation for sugar syrups production: Techno-economic assessment Authors: Tsz Him Kwan, Khai Lun Ong, Md Ariful Haque, Sandeep Kulkarni, Carol Sze Ki Lin PII: DOI: Reference:

S0957-5820(18)31069-3 https://doi.org/10.1016/j.psep.2018.10.018 PSEP 1548

To appear in:

Process Safety and Environment Protection

Received date: Revised date: Accepted date:

3-3-2018 11-9-2018 13-10-2018

Please cite this article as: Kwan TH, Ong KL, Haque MA, Kulkarni S, Lin CSK, Biorefinery of food and beverage waste valorisation for sugar syrups production: Techno-economic assessment, Process Safety and Environmental Protection (2018), https://doi.org/10.1016/j.psep.2018.10.018 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Biorefinery of food and beverage waste valorisation for sugar syrups production: Technoeconomic assessment

Tsz Him Kwan1, Khai Lun Ong1, Md Ariful Haque1, Sandeep Kulkarni2, Carol Sze Ki Lin1,*

School of Energy and Environment, City University of Hong Kong

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Independent Sustainable Packaging Consultant, 4501 May Apple Drive, Alpharetta GA 30005,

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United States

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*Corresponding author: Carol S. K. Lin, School of Energy and Environment, City University

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E-mail: [email protected]

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of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong

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Telephone: +852 3442 7497, Fax: +852 3442 0688

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Graphical abstract

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Highlights 

Techno-economic study was conducted for F&B valorisation via integrated biorefinery Fructose syrup, high fructose syrup, and glucose-rich syrup were the main products

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By-products are proposed for various agricultural and industrial applications

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Price of sugar syrups was the largest determinant of the profitability

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Motivated demonstration for F&B industries adopting novel biotechnological

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

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processes

Abstract

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Techno-economic analysis was conducted to evaluate a food and beverage (F&B) waste

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valorisation process for sugar syrup production via integrated biorefinery. A comprehensive

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process model was developed with a capacity of 10 metric tons (MT) hour-1 of food waste and

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14 MT hour-1 of beverage waste. Three scenarios were proposed with different types of sugar syrups as the main products: Scenario I) fructose syrup, Scenario II) high fructose syrup-42,

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and Scenario III) glucose-rich syrup. Mass balance showed conversion yields of 0.24 MT sugar syrups per MT of F&B waste, while lipids (0.07 MT per MT of F&B waste) and insect feed

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(0.44 MT per MT of F&B waste) were the co-products proposed to be used for other industrial

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biorefinery processes. All scenarios were observed to be economically self-sustainable with net profit generation (US$11-26 million year-1) and positive net present values (US$92-294 million). Along with the net production costs (US$443-665 MT-1), the sugar syrups derived

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from the F&B waste have relatively low minimum selling prices of US$157-747 MT-1 at a 5% discount rate. Lastly, sensitivity analysis was performed which found that the prices of sugar syrups were the largest determinants of their profitability. This study proposes a significant techno-economic basis for F&B waste biorefinery, which offers a successful demonstration for food and drink industries adopting these biotechnological processes for the same plant size. 2

Keywords: Food and beverage waste; Fructose; Glucose; Purification; Saccharification; Sensitivity Analysis

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Nomenclature Chemical engineering plant cost index

FCI

Fixed capital investment cost

HFS

High fructose syrup

HMF

Hydroxymethylfurfural

HKOWRC

Hong Kong Organic Waste Recycling Centre

IRR

Internal rate of return

PC

Purchase cost of equipment

PHB

Polyhydroxybutyrate

PLA

Poly(lactic acid)

MT

Metric ton

NPV

Net present value

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Return on investment Simulated moving bed

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SMB

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National Renewable Energy Laboratory

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ROI

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NREL

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CEPCI

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1. Introduction In recent years, there has been a pressing need to find an alternative to petroleum refinery because of the limited reserves of non-renewable crude oil and severe pollution caused by oil refining. Biorefinery has been proposed as a promising replacement for more sustainable

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production of fuels, materials and chemicals by utilising renewable biomass and developing

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environmentally friendly technologies.

According to International Energy Agency Bioenergy Task 42, biorefinery is defined as “the sustainable processing of biomass into a spectrum of marketable products (food, feed, materials

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and chemicals) and energy (fuels, power and/or heat)” (IEA Bioenergy, 2012). It also indicates

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that biorefinery can be a concept, a facility, a process, a plant, or even a cluster of facilities,

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which integrate many different areas of knowledge encompassing chemical engineering, chemistry, biology and biochemistry, biomolecular engineering and other fields (IEA

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Bioenergy, 2012). Biorefinery is analogous to conventional oil refineries where multiple products and fuels are extracted and produced from petroleum nowadays. As stressed by the

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IEA, biorefinery does not only address our need for substitution with bio-based products having equivalent functional characteristics to fossil resource-derived products; it offers a unique

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advantage by addressing issues of sustainability in all aspects – economic, social and environmental. It employs renewable biomass as feedstock and decreases production costs

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through economies of scale and the development of green technologies to produce bio-based products. The variety of regionally based feedstocks and practices allows biorefinery to be flexible for application across the globe. Possible feedstocks that can be used in a biorefinery include sugar beet, black liquor, wheat, corn, wood, agricultural residues, sugar cane, surplus food, straw, and aquatic biomass, but also the biomass fraction of municipal solid waste.

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Among the biomass resources, valorisation of waste residues has great opportunities in biorefinery from the perspectives of waste treatment, nutrient recovery, and environmental pollution associated with improper waste disposal (Burange et al., 2016). Koutinas et al. (2014) presented integrated biorefinery for the first time to utilise various waste and by-product streams for restructuring the conventional manufacturing processes in food, pulp and paper and

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the first generation biofuel industries. Mohan et al. (2017) further summarised a number of waste-based biorefinery approaches and envisioned the change from a linear economy towards

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a circular economy by the adaptation of such integrated biorefinery in different industrial sectors.

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There has been considerable interest in valorisation of food waste in biorefineries

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(Burange et al., 2016). Annual generation of food waste has surpassed 1.3 billion metric tons

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globally (FAO, 2011). In fact, a large proportion is wasted before consumption mainly because

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of insufficient purchase planning and stringent quality standards (FAO, 2011). A few reports

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revealed that most of the food and beverage (F&B) waste generated by the industry is edible and can be avoided (Hyman, 2009; Quested et al., 2013). Recent examples are the recovery of

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l-malic acid from beverage industrial wastewater using electrodialysis process (Lameloise et al., 2009 and 2012). Biorefinery is a novel approach to valorise F&B waste besides the

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conventional recycling technologies such as composting, anaerobic digestion and animal feed supplement. Intensive studies have been recently published by our group to evaluate the

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complexity and potential of F&B waste as biorefinery feedstock in terms of composition, volumes, and the possibilities to be converted into value-added products (Haque et al., 2017; Kwan et al., 2018a, 2018b; Yu et al., 2018). In general, F&B waste is composed of starch (3060%, w/w), free sugars (10%, w/v), proteins (10%, w/w) and lipids (20%, w/w) (Kwan et al., 2018a; Ventura et al., 2011). Ventura et al. (2011) reported the sugar content of popular

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sweetened beverages mainly in the form of high fructose corn syrup (HFCS). These are ideal feedstocks in biorefinery for sugar production due to the high levels of starch and free sugars, but sugar refining processes must be applied thereafter to remove the impurities such as preservatives, colorants, caffeine, ions and soluble proteins (Kwan et al., 2018b). A bioconversion process was developed and successfully demonstrated at laboratory and pilot

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scales to recover fructose syrup and glucose-rich syrup from F&B waste by saccharification,

adsorption, ion exchange chromatography, isomerisation, glucose-fructose separation using a

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simulated moving bed (SMB) system, and evaporation of sugar syrups (Kwan et al., 2018b; Yu

et al., 2018). More than 89% of sugars were recovered from the hydrolysate yielding 0.14 kg of sugars per kg of F&B waste (Kwan et al., 2018b). The fructose syrup also conformed to the

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industrial requirements including appearance, fructose and glucose content, pH, sulphite ash,

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and the threshold limits for heavy metals and bacteria (Kwan et al., 2018b).

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This study proposed a novel integrated F&B waste biorefinery through the production of

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different types of sugar syrups for various industrial processes. For example, the fructose syrup derived from F&B waste has been used for hydroxymethylfurfural (HMF) synthesis (Yu et al.,

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2018), which was proposed by Kaur et al. (2018) for bio-based production of polyethylene furanoate (PEF) and polyethylene terephthalate (PET) in the plastic industry. Kwan et al. (2016)

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also presented co-utilisation of glucose and fructose as carbon sources for fermentative lactic acid production with Lactobacillus casei Shirota, which demonstrated the feasibility of using

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glucose-rich syrup for fermentation processes. On the other hand, the by-product streams containing the other ingredients originating from F&B waste (e.g. proteins and lipids) have been utilised for the generation of value-added products. For example, Pleissner et al. (2015) and Karmee et al. (2015) harvested the lipids from restaurants’ leftovers and bakery waste for surfactants and biodiesel production, respectively. The remaining solids harvested after

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saccharification were used to feed insects (Hermetia illucens) to provide insect biomass as an alternative protein supply for the husbandry industry (Kwan et al., 2018a). By applying such integrated bioconversion processes, the F&B waste could be converted into various valueadded products and useful feedstocks including: 

glucose and fructose syrups with different industrial applications, e.g. sweeteners such

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as HFS-42 (White, 2014), carbon sources in fermentation (Kwan et al., 2016), and bioplastics via HMF synthesis (Yu et al., 2018).

lipids as feedstock for a wide spectrum of industrial processes, e.g. polyurethane as

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building materials (Kaur et al., 2018), biodiesel (Karmee et al., 2015), and surfactants

nutrient-rich solids & retentate as insect feed for alternative protein supply

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(Pleissner et al., 2015).

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(Lin et al., 2017).

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Although the technical feasibility of such integrated biorefinery has been proven by a number of laboratory studies, the economic aspect has never been explored. Therefore, a

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comprehensive techno-economic study is needed to (i) estimate the economic performance of the bioprocesses, (ii) identify the key process and economic factors and (iii) evaluate the

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investment risks. This techno-economic assessment is of significant importance for the longterm development and commercial success of F&B waste-based biorefinery. It may also

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develop new opportunities for various industries to adopt bio-based production by F&B wastederived biomass, which will have a significant impact on the establishment of a circular bio-

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economy.

This study focused on techno-economic assessment to investigate the technical feasibility, profitability and extent of investment risk with regard to integrated biorefinery to achieve F&B waste valorisation. Three scenarios were proposed with different types of sugar syrups as the

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main products: Scenario I) fructose syrup; Scenario II) HFS-42; and Scenario III) glucose-rich syrup. The selections of these three types of sugar syrups were based on their potential applications in the industries. The reasons for selection of these three configurations are as follows: (I) Fructose syrup - as pointed out in our previous studies, PepsiCo Advanced Research Team – Sustainable Packaging in the US would like our research group to explore

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the technical feasibility for developing a bioconversion process to convert its expired F&B

wastes to fructose syrup, which could be subsequently used for non-food packaging application

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(Kwan et al., 2018a, 2018b; Yu et al., 2018). (II) High fructose syrup (HFS-42) is a glucosefructose mixture which would be considered as a second generation feedstock to be used in industrial biotechnology for production of biobased products (e.g. enzymes and organic acids).

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In this case, the sugars could be valorised without the requirement for isomerisation and

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glucose-fructose separation. Indeed, the assumption of selling glucose-fructose mixture to the

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current biotechnology industry has not been justified, but it is of interest to investigate the

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techno-economic performance and to compare the results with the production of fructose syrup.

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(III) Glucose-rich syrup – similar to HFS-42 in Scenario 2, glucose rich syrup can be directly sold as the main end-product to the industrial biotechnology without isomerisation and

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glucose-fructose separation. Since isomerisation did not take place, the major component of syrup should be glucose and the remainder should be fructose. It would be interesting to

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compare its techno-economic performance with the other two scenarios as significant cost

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reduction in downstream processing steps are anticipated in this scenario.

Process flowsheets have been developed for each scenario accompanied with the calculations of mass and utility balance. Lastly, sensitivity analysis was conducted to identify the key process and economic factors regarding the plant’s economy. To the best of our knowledge, this is the first study to focus on the techno-economic evaluation of F&B waste biorefinery.

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2. Methods 2.1. Simulation description In the model, a plant was simulated with a capacity of 10 MT h-1 food waste (wet weight) and 14.12 MT h-1 beverage waste based on a solid-to-liquid ratio of 70% (w/v) (Yu et al., 2018). It

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was operated in continuous mode with 8,300 operation hours per year (95% of the plant’s capacity), which corresponds to an annual processing capacity of 83,000 MT food waste and

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117,196 MT beverage waste (Koutinas et al., 2016). The plant is located in Hong Kong with a

20-year lifetime, including 1 year of construction and start-up phase. The mass and energy balance of the process of bioconversion of F&B waste to sugar syrups was modelled and

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evaluated by SuperPro Designer 8.0, which is analogous to the one proposed by Demichelis et

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al. (2018). While Microsoft Excel 2010 was used to conduct profitability analysis, cumulative

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2.2. Process description

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cash flow and sensitivity analysis.

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The processes simulated in this study have already been demonstrated at laboratory and pilotscales which provide technical data on process specifications and efficiencies for the

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conversion for developing the models (Kwan et al., 2018a, 2018b; Yu et al., 2018). The bioconversion processes consist of five main processing sections, namely saccharification,

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hydrolysate purification by adsorption and ion exchange chromatography, isomerisation, glucose-fructose separation using a simulated moving bed (SMB), and evaporation of sugar

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syrups. Different sugar refining strategies were proposed in three scenarios in order to investigate the techno-economic performance of producing fructose syrup (Scenario I), HFS-42 (Scenario II) and glucose-rich syrup (Scenario III). A simple process flow of each scenario is depicted in Figure 1, while Table 1 summarises the parameters used for developing the models which were adapted from literatures and previous comprehensive studies

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(Kwan et al., 2018a; 2018b; Yu et al., 2018). A description of each section is provided in Section 2.2.1-2.2.5.

2.2.1 Process of saccharification The purpose of saccharification is to hydrolyse the starch and sucrose present in mixed F&B

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waste for the recovery of glucose and fructose. The process begins with mixing the beverage waste with food waste at a solid-to-liquid ratio of 70% (w/v) (Yu et al., 2018). Since there is

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8.4% moisture content in food waste as reported in our previous publication (Kwan et al.,

2018a), only 13.5 m3 (14.1 MT) of beverages is needed to reach the 70% (w/v) solid-to-liquid ratio. The mixture is then heated to 50oC, followed by the addition of glucoamylase (1%, w/w

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of mixed food waste) and sucrase (0.025%, w/v of beverage waste). The pH of the mixture is

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around 5, which is within the optimal range of enzyme activity and thus adjustment is not

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needed (Kwan et al., 2018a). The hydrolysis is performed under 50oC for 12 hours in

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saccharification tanks (Kwan et al., 2018a). Thirteen identical saccharification tanks operate in

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batch mode with staggered start times. There is always one tank loading and one unloading, while the actual saccharification takes place in the remaining 11 tanks (Hobb, 2009). It is

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assumed that sucrose is completely hydrolysed into glucose and fructose, and 98% of starch is hydrolysed to glucose according to laboratory findings using a 2 L bench top bioreactor

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(Kwan et al., 2018b). After that, the lipids and remaining solids are separated out by centrifugation at 10,000g, while the supernatant is transferred for clarification and filtration for

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removal of suspended solids and 92% sugars by mass are recovered according to the experimental results (Kwan et al., 2018b). There are two identical units operating in batch mode with staggered start times so that one unit is in operation, while another is washed with 4% NaOH or is on stand-by.

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2.2.2. Process of purification The hydrolysate first passes through an adsorption column for the removal of colours, odours, and organic materials, followed by ion exchange columns to remove the ions and soluble proteins. There are 2-3 identical columns operating in batch mode with staggered start times to ensure there is one unit in operation, while the remaining units are in washing or stand-by mode.

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The adsorption column is packed with macroporous adsorber resin (Lewatit® VP OC 1064

MD PH, Lanxess, Germany), while the cation and anion exchange columns are packed with

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DOWEX™ MONOSPHERE™ 88 and DOWEX™ MONOSPHERE™ 66, respectively. The

operating conditions (column contact time, breakthrough time and resin lifetime) are summarised in Table 1 based on experimental results and information provided by the

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manufacturer. The adsorption, cation exchange and anion exchange resins are regenerated by

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2 BV of 70% methanol, 3 BV of sulphuric acid (1M), and 3 BV of NaOH (4%), respectively.

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It is assumed that 95% of methanol is recovered by the distillation column (Koutinas et al.,

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subsequent economic analysis.

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2016). The wastewater is discharged as sewage and the relevant cost is included in the

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2.2.3. Process of isomerisation

The purified sugar syrup passes through an isomerisation column, where the immobilised

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enzymes convert part of the glucose to fructose at 60oC. Our previous study suggested that the isomerisation column should be packed at a density of 18 g isomerase in 120 mL of column

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volume, and meanwhile at least 30 minutes of column contact time is required to reach isomerisation equilibrium, which ranges from 45-50% fructose content (Kwan et al., 2018b). The enzymes were replaced after a year based on the information provided by the manufacturer (Novozymes, 2013).

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2.2.4 Process of glucose-fructose separation by a SMB The purpose of this step is to separate the fructose from the sugar syrup by using a simulated moving bed system which consists of twelve columns, two inlet streams (feed and water as mobile phase), and two outlet streams (fructose-rich stream and glucose-rich stream). The sugar syrup is first concentrated to attain a concentration of 200 g L-1 glucose and 200 g L-1

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fructose before feeding into the SMB. An optimisation study was conducted and reported in

our recent publication (Yu et al., 2018). The result adopted in this model was that 41% of

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fructose (by mass) is separated into the fructose-rich stream (87.6 g L-1 of fructose), while the remaining sugars result in the glucose-rich stream which contains 70.7 g L-1 glucose and 41.9 g

L-1 fructose (Yu et al., 2018). The glucose-rich stream is evaporated and recirculated to the

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isomerisation column for conversion from glucose to fructose. A recirculation loop and

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2.2.5 Process of sugar syrup evaporation

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calculation was done by using SuperPro designer 8.0. This will be discussed in Section 3.1.

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Evaporation of sugar syrups is carried out to attain no less than 70% by mass, according to the industrial standard (i.e. China National Standards method GB/T 20882-2007). A multiple-

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effect evaporator is employed to evaporate water efficiently using the heat from steam. The condense water in the evaporation process is recovered and re-used in the plant. The water

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balance will be discussed in Section 3.1 where water usage, wastewater generation and condense water recovery are considered. It is a necessary step in the industry to concentrate the

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sugar syrup for the convenience of delivery, ease of handling and an extended shell life. As reported in our previous study, the concentrated HFS derived from food and beverage waste conforms to industrial standards including heavy metal content, physicochemical properties and microbiological tests.

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2.3. Economic analysis The capital cost, operation cost and revenue generation were estimated to study the economic performance of the three scenarios. Cost-benefit analysis was then conducted to calculate the profitability and cash flow, followed by sensitivity analysis to evaluate the investment risk and key factors related to the plant’s economics. The economic performance of each scenarios was

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compared through these analyses.

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2.3.1. Total capital cost estimation

The capital cost was estimated by reference to fixed capital investment (FCI) cost and working capital cost. The FCI cost comprises the expenditure on plant construction, including

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equipment costs, associated costs of installation and piping, and other related costs. The FCI

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cost was estimated based on the method of the percentage of delivered-equipment cost for

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solid-fluid processing plant as described in Peters (2003). Table 1 presents the details of the

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estimation. The equipment costs were obtained from recent cost data in the 2011 NREL report

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on bioethanol production, textbooks and literature (Peters et al., 2003; Humbird et al. 2011) and the built-in module in SuperPro Designer. The cost of a particular type of equipment (Cp,0)

𝐶𝐸𝑃𝐶𝐼𝑡 𝐶𝐸𝑃𝐶𝐼𝑡0

𝑋 𝑛

𝐶𝑝,0 ( ) 𝑋 0

𝐸𝑞𝑢𝑎𝑡𝑖𝑜𝑛 (1)

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𝐶𝑝 =

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with a different characteristic size (X) in a different year (t) was calculated by Equation (1).

where CEPCIt is the chemical engineering plant cost index at year t published monthly in the Chemical Engineering Magazine and the exponent (n) is characteristic of the particular type of

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equipment. The exponent (n) was set to be 0.6 (sixth-tenths-factor-rule) for order-of-magnitude estimation of new equipment cost (Green and Perry, 2008). The equipment-specific installation cost was estimated from the equipment cost using appropriate multiplication factors obtained from literature (Green and Perry, 2008; Koutinas et al., 2016; Peters, 2003). Land cost was neglected because collaboration with the property management company and local food waste 13

recycling company was expected (HKOWRC, 2016; Kwan et al., 2015). The working capital, which was used to cover the expenses of the initialisation of the plant in the start-up phase (e.g. raw material cost, utilities cost and testing of equipment) was assumed to be 15% of the FCI cost (Peters, 2003). Lastly, no further capital cost or revenue from the resale of plant’s facilities

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is generated after the plant’s lifetime.

2.3.2. Operation cost estimation

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The operating cost is composed of total variable production costs, fixed charges, plant

overhead costs and general expenses (see Table 1) (Peters, 2003). The costs of chemicals were obtained from the chemicals industry (ICIS, 2015), while the specific costs for enzyme and

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resin were acquired by personal communication with the manufacturers. The number of

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labourers was estimated using Ulrich’s method with the assumption of 50 working hours per

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week per shift and a US$20,000 annual salary (Ulrich, 1984). In fact, the estimated annual

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salary from this method is similar to the current annual salary level of employees in Hong Kong

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(Census and Statistics Department, 2018). Utilities consumption was calculated from the mass and energy balance in SuperPro Designer®. The associated up-to-date utility costs were

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obtained from local utility companies, literature and online databases (CLP, 2017; Intratec, 2017). The logistics cost for F&B waste collection was acquired by personal

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communication with a local food waste recycling company (HKOWRC, 2016). The charges for discharging wastewater were obtained based on local regulation (Environmental Protection

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Department, 2015). The depreciation of the FCI cost was determined using the straight-line method for a 20-year lifetime with negligible salvage value. Table 1 summarises the estimation of other components in the operating cost based on the method described in Peters (2003).

2.3.3. Revenue

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Revenue was determined by sales of products and the food waste treatment service fee. The current market prices of fructose syrup, HFS-42, glucose-rich syrup, lipids and insect feed are US$935 MT-1, US$623 MT-1, US$755 MT-1, US$500 MT-1 and US$65 MT-1, respectively (ASB, 2016; Eco-Nutrient Biotechnology Ltd., 2017; USDA, 2017a; 2017b). The food waste treatment fee (US$77 MT-1) was obtained by personal communication with a food waste

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recycling company (Hong Kong Organic Waste Recycling Centre) (HKOWRC, 2016).

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2.3.4. Profitability analysis

Economic performance was evaluated by a number of indicators including net production cost, minimum selling price, gross profit, net profit, net present value (NPV), internal rate of return

) is the operating cost per 1 MT of sugar syrup produced in the corresponding scenarios, while

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1

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(IRR), payback time, and return on investment (ROI). First, the net production cost (US$ MT-

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the minimum selling price (US$ MT-1) was determined when the NPV reached zero. Then, the

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gross profit measures the profitability by subtracting the annual revenue from the annual

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operation cost while the net profit also takes income tax (16.5%) into account. Lastly, the net present value (NPV) indicates the economic feasibility of the process in the entire plant’s

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lifetime (20 years) by discounting the future cash flows to the present value. A positive NPV

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means the process is profitable and vice versa. The NPV is calculated by Equation (2). 𝑇

𝑁𝑃𝑉 (𝑈𝑆$) = ∑ 𝑡=1

𝐶𝑡 − 𝐶0 (1 + 𝑑)𝑡

𝐸𝑞𝑢𝑎𝑡𝑖𝑜𝑛 (2)

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where t is the lifetime in years, C0 is the initial investment, Ct is the net cash flow during period t and d is the discount rate. The IRR which reflects the investment’s efficiency is the discount rate where the NPV value becomes zero (see Equation (2)). The payback time describes the duration to recoup the investment cost. Lastly, the ROI is the cash return rate without taking the discount rate into account. The ROI is defined in Equation (3).

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𝑅𝑂𝐼 (%) =

𝐴𝑛𝑛𝑢𝑎𝑙 𝑛𝑒𝑡 𝑝𝑟𝑜𝑓𝑖𝑡 𝑋 100 % 𝐶𝑎𝑝𝑖𝑡𝑎𝑙 𝑐𝑜𝑠𝑡

𝐸𝑞𝑢𝑎𝑡𝑖𝑜𝑛 (3)

Cash flow patterns were investigated by the cumulative cash flow for each year over the plant’s lifetime. The patterns were evaluated and compared between the three scenarios at different

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discount rates.

2.3.4. Sensitivity analysis

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Sensitivity analysis was conducted to evaluate the impact of different variables on the

economic performance of each scenario. Since the techno-economic model was built based on a few subjective assumptions and the global economic environment can fluctuate, a number of

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variables were independently evaluated at a ±50% variation at the beginning of the plant’s

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lifetime. They included capital cost, raw materials cost, labour cost, utility cost and products’

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selling prices. NPV was used as the indicator of the plant’s profitability at a 5% discount rate

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(Broadie et al., 2007).

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3.1. Mass balance

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3. Results and discussion

Table 2 summarises the overall component balance of the process in annual operation while

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the mass balance for each stream is presented in the process flow diagrams which were extracted from SuperPro Designer® (see Figure S1, S2 and S3). As shown in the Figure S1-S3, the plant processes 10 MT h-1 food waste and 14.1 MT h-1 beverage waste. Saccharification

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was first performed in all scenarios to recover 5.1 MT h-1 glucose and 0.7 MT h-1 fructose by hydrolysing the starch and sucrose, corresponding to a sugar recovery yield of 0.23 g of sugar per gram of mixed F&B waste. The remaining residue (7.6 MT h-1), lipids (1.7 MT h-1) and suspended solids (0.1 MT h-1 precipitate and 2.9 MT h-1 retentate) was removed by centrifugation, clarification and filtration to obtain a hydrolysate which contained 288.6 g L-1 16

glucose, 40.0 g L-1 fructose and a trace of preservatives, caffeine, colourants, ions and soluble proteins (Kwan et al., 2018b). The hydrolysate was then purified by adsorption and ion exchange chromatography to remove more than 99% of these impurities before entering different sugar refining strategies in Scenario I, II and III (Kwan et al., 2018b). In general, around 78% (by mass) of glucose (4.0 MT h-1) and fructose (0.5 MT h-1) was recovered in the

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hydrolysate. Sugar loss was identified in the streams of remaining solids and retentate, which had 0.9 MT h-1 and 0.4 MT h-1 of free sugars, respectively. The utilisation of these sugar-rich

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by-product streams will be discussed in Section 3.3.

In Scenario I, the purified hydrolysate was mixed with 24.8 kg NaOH for adjustment of pH

U

to 7-8 before entering the isomerisation column, where the immobilised isomerase converts

N

glucose to fructose until a fructose content of 45%. Ion exchange chromatography was then

A

applied to remove the sodium ions and yellowish colour detached from the isomerase. The

M

sugar syrup was concentrated to a 400 g L-1 sugar concentration by evaporation and then

ED

entered into the SMB system, where 163 MT h-1 water was fed as a mobile phase for separation of fructose. The glucose-rich stream (185.0 MT h-1) was concentrated to around 320 g L-1 sugar

PT

concentration and recirculated back to the isomerisation column for fructose production. A recycling loop was built as shown in the process flow diagram (see Figure S1). It increased the

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throughput of isomerisation column from 14.0 MT h-1 to 75.6 MT h-1, in which 13.4 MT h-1 glucose and 11.0 MT h-1 fructose were contained. Only 2% of sugar loss was found during the

A

refining processes, and 5.9 MT h-1 of fructose syrup was produced from the F&B waste. In Scenario

II

where

HFS-42 was produced, the purified hydrolysate underwent pH adjustment, isomerisation and ion exchange chromatography under the same conditions as Scenario I. However, fructose separation using the SMB system was not needed in the production of the HFS-42. Therefore,

17

no recirculation loop was built and the throughput of isomerisation column remained as 14.0 MT h-1 which contained 2.5 MT h-1 glucose and 2.0 MT h-1 fructose. At the end of the process, 5.9 MT h-1 HFS-42 was produced and it contained around 4.5 MT h-1 sugars, of which 42% was fructose. In Scenario III, the purified hydrolysate was directly evaporated into glucose-rich syrup (5.9 MT h-1), in which fructose only accounted for 12.2% of total sugars

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since isomerisation did not take place. Overall, three different types of sugar syrups (fructose

syrup, HFS-42 and glucose-rich syrup) were produced in Scenario I, II and III, respectively.

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The conversion yields (0.24 MT sugar syrup per MT of F&B waste) were identical for all scenarios but the corresponding sugar composition profiles were different.

U

Regarding the water input and wastewater generation, Scenario I had the highest water input

N

(1,538,825 MT year-1), which was 5-8 times of that in Scenarios II and III. This could be

A

attributed to the water consumption for fructose separation where over 80% of the water in

M

Scenario I was used as a mobile phase in the SMB system. This water content was eventually

ED

recovered by evaporation in the process resulting in the net water consumption of 216,967 MT year-1. However, the accompanied intensive energy consumption for evaporating

PT

such a large amount of water may hamper its environmental performance and lead to a high utility cost which will be discussed in Section 3.2. Besides, wastewater is generated by

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membrane washing in the filtration unit (9,628 MT year-1) and resin is regenerated in the units of

adsorption

(12,201 MT year-1)

and

ion

exchange

chromatography

A

(252,569 MT year-1). A laboratory study was conducted to minimise the wastewater generation by

evaluating

different

resins,

regenerants

chemicals

and

operating

conditions

(Kwan et al., 2018b). It is admitted that wastewater generation can hardly be avoided in chromatographic separation across various industrial processes (Pleissner et al., 2016). The subsequent economic analyses should address whether the generation of wastewater will lead

18

to a significant operating cost and become a critical factor in regard to economic performance.

3.2. Capital & operating cost Table 3 presents the capital cost including both fixed capital investment (FCI) and working capital for all the scenarios. The equipment cost for Scenario I (US$23,944,722) and

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Scenario II (US$14,134,722) is relatively higher than that of Scenario III (US$8,912,722) since additional equipment (e.g. isomerisation column, SMB system and evaporators) are needed for

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the production of fructose syrup and HFS-42. In fact, the costs of equipment involved in sugar refining (i.e. adsorption, ion exchange chromatography, SMB system and evaporators) contribute the most significant part (77-92%) to the total equipment cost for all the scenarios

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(Table 3), because there are multiple units operating in batch mode for a few operations. The

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most expensive equipment is the evaporator (EV-103; Table 1) which accounts for 25.8% of

A

the total equipment cost in Scenario I. It is equipped with the highest evaporation capacity

M

(123.4 MT h-1) to concentrate a large volume of glucose-rich stream (185.0 MT h-1) from the

ED

SMB unit (see Figure S1). It is also one of the main causes of the relatively lowered capital costs for Scenarios II and III. Apart from the bare equipment cost, additional costs for building

PT

the plant were anticipated and are summarised in Table 3. The associated percentage of the cost contribution of each item to the FCI is based on the existing literature (Peters, 2003). Working

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capital which is assumed to be 15% of the FCI is expected to cover the expenses of the initialisation of the plant in the start-up phase, such as purchasing raw material, testing

A

equipment and training labourers.

3.2. Operating cost Estimated operating cost is presented in Table 4. A plant processing 200,221 MT of F&B waste year-1 had the total annual operating cost of US$60,595,458, US$40,575,681, and

19

US$34,381,099 in Scenarios I, II, and III, respectively. Figure 2 illustrates the cost distribution of different steps in the bioconversion process. It is worth noting that the cost associated with purification is the largest expenditure, contributing 34-50% of the total operation cost in all scenarios. This is mainly because the purification processes require massive amounts of resin and regenerants chemicals to remove the impurities originating from the F&B waste, such as

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preservatives, caffeine, colorants, soluble proteins and ions (Kwan et al., 2018b). The cost of

purchasing adsorption resin (Lewatit VP OC 1064 MD PH resin) contributes 14-25% to the

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operating costs. Overall, the net production costs are calculated to be US$665 MT-1, US$571 MT-1 and US$443 MT-1 for fructose syrup, HFS-42 and glucose-rich syrup, respectively (see Table 4). Conventionally, production of glucose- and fructose-based syrups involves wet

U

milling of corn for the recovery and purification of starch before saccharification and sugar

N

refining processes. The corn first undergoes chemical pre-treatment with sulphuric acid

A

followed by physical separation of the co-products and starch. This process is criticised for

M

being energy-intensive, time-consuming and increases air pollutant emission (SO2) to the

ED

atmosphere (Ramirez et al., 2008). In this respect, Ramirez et al. (2009) developed enzymatic corn wet milling as an environmentally friendly method to produce corn starch and performed

PT

similar techno-economic analysis to estimate the commercial viability. The net production costs of starch are around US$193 per MT for both chemical and enzymatic corn wet milling

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methods in which over 80% is contributed by purchasing corn alone (Ramirez et al., 2009). Comparatively, this biorefinery provides unique advantages by using F&B waste as feedstock

A

since it contains readily available starch and free sugars which can be directly recovered by saccharification. It does not only prevent the associated problems and costs of wet milling, F&B waste is also a cost-free material which could significantly reduce the raw materials cost in the process. Aden & Foust (2009) conducted a techno-economic analysis of the dilute sulfuric acid and enzymatic hydrolysis process for the conversion of corn stover to ethanol and

20

reported pretreatment contributed the second largest cost (19%) to the process because of the high metallurgy costs associated with high temperature, pressure and corrosive requirements.

Raw material is usually the major cost contributor in techno-economic studies on biorefinery because massive amounts of feedstock and chemicals are usually required to achieve efficient

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product synthesis and recovery (Klein‐Marcuschamer, 2013; Kumar et al., 2018). Some studies have also highlighted the high cost of enzymes among the raw materials involved in the models.

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Choi and Lee (1997) reported the glucose contributed 30.7% to the total operating cost in

fermentative production of PHB, which results in a production cost of US$6,100 MT-1. Our

U

previous study of lactic acid, lactide and PLA production observed raw material is the most

N

significant economic driver in the process that accounts for 21-23% of the total operating cost

A

(Kwan et al., 2018c). In this study, a similar cost distribution was observed across the three

M

scenarios that consumables (19-25%) and raw materials (12-20%) are the largest portions. However, it is worth noting that the utility costs in Scenario I (US$8,073,262) are much higher

ED

than that of Scenario II (US$916,805) and Scenario III (US$906,205), which requires further

PT

exploration of utility usage across these scenarios.

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As mentioned earlier, the utility usage is analysed in Table 5 where the annual consumption of utilities and the associated costs of each process are summarised. In Scenario I, it is observed that the steam consumption (640,934 MT) was about 12 times higher than that in Scenarios II

A

and III, which contributed the most significant part (US$7,691,212) to the utility costs. The intensive energy consumption required by fructose syrup production is found in the evaporator (EV-103; see Figure S1). This is in line with the discussion presented in Section 3.2. This evaporator with the highest capacity consumes huge amount of steam to vaporise the water from the glucose-rich stream. This is important to consider the reduction of energy demand or

21

alternative technology to completely or partially fulfil the energy self-sufficiency paradigm in the future study. Then, the main usage of electricity across different scenarios is by the saccharification tanks (1,975,400 kWh) where agitation is constantly supplied to ensure the homogeneity of the substrate. Effective mixing is extremely important for saccharification in which the hydrolysis yield can significantly drop to 63.2% due to insufficient stirring (Yu et al.,

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2018). This is also in line with Koutinas et al. (2016) who reported that around 80% of electricity usage is related to agitation in fermenters in the bioprocess of 2,3-butanediol

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production. Besides, water is also a major utility in sugar syrup production as process water,

cooling water and irrigation water are inevitably needed in the current industry in which corn is processed into various sugars and sugar syrups (White, 2014). Process and cooling water

U

usage can be minimised by advanced plant design, but irrigation water applied to corn fields is

N

necessary. Vink and Davies (2015) reported that irrigation water accounts for around half of

A

the total water used in poly(lactic acid) production from corn according to life cycle analysis.

M

It could be also one of the advantages of using F&B waste as a raw material where no additional

ED

irrigation water is needed before saccharification, whereas the beverage waste itself already

PT

contains a massive amount of water for the process, which in turn decreases the net water input.

3.4. Revenue and profitability analysis

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To assess the economic viability of F&B waste as feedstock for sugar syrups production,

revenue and profitability analysis were conducted. As shown in Table 5, annual revenue

A

generated in Scenario I, Scenario II and Scenario III was US$73,725,592, US$58,521,389, and US$64,951,932, respectively. Sale of sugar syrups contributed more than half of the revenue across

all

the

scenarios.

Although

identical

amounts

of

sugar

syrups

(48,638 MT year-1) were produced, the different sugar composition profiles led to variations on the market prices (i.e. US$935 MT-1 for fructose syrup, US$623 MT-1 for HFS-42, and

22

US$755 MT-1 for glucose-rich syrup). Correspondingly, the annual revenue generated in Scenario I in which fructose syrup is the main product was the highest across the scenarios. On the other hand, sales of co-products (lipids and insect feed) contributed around 20% of the revenue in all the scenarios. The feasibility of using food waste-derived lipids for biodiesel production has already been evaluated in our previous study, where almost 100% conversion

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was achieved through alkali-catalysed transesterification using KOH (Karmee, 2015). Recent studies also demonstrated conversion to a variety of products using for the lipids such as

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polyurethane (unpublished result), plasticiser and surfactant (Pleissner et al., 2015). The sugarrich remaining solids, retentate and precipitate have been proven to be ideal substrates for

feeding insects, and in particular the remaining solid also consist of around 55% carbohydrates,

U

15% proteins and 19% lipids (dry weight) (Kwan et al., 2018a). The high levels of free sugars

N

provide readily available carbon sources for the larvae of Hermetia illucens to consume, which

A

boosts the growth rate with more than a 75% survival rate within 10 days (Eco-Nutrient

M

Biotechnology Ltd., 2017; Lin et al., 2017). The insect biomass samples consisted of more than

ED

50% crude protein, which is extremely favourable for feeding poultry (Maurer et al., 2015). It is admitted that the market prices of these by-products streams are subjected to various factors

PT

including the intended application, quality, market situation, regions, etc. Therefore, the sensitivity analysis presented in Section 3.5 will address the effect of the selling prices of these

CC E

by-products on the plant’s economics.

A

Profitability analysis was carried out to evaluate and compare the economic performance

between the scenarios in terms of gross profit, net profit, NPV, IRR, ROI and payback time. As shown in Table 5, all scenarios were profitable as indicated by net profit generation (Scenario I:

US$10,963,662

year-1;

Scenario

II:

US$14,984,666

year-1;

Scenario

III:

US$25,526,646 year-1) and positive NPVs (Scenario I: US$92,469,924; Scenario II:

23

US$157,392,951; Scenario III: US$293,571,652). Scenario III has the highest economic return with the IRR (88.0%), ROI (58.9%) and payback year (2.3 years) at a 5% discount rate. On the other hand, the minimum selling prices of fructose syrup (US$747 MT-1), HFS-42 (US$302 MT-1) and glucose-rich syrup (US$157 MT-1) were lower than that of wholesale market prices presented in Table 5. This reflects that the sugar syrups derived from F&B waste

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by this biorefinery process should have sufficient competitiveness in the market. In addition,

cumulative cash flow was calculated and illustrated in diagrams at different discount rates in

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Figure 3. The capital investment was spent in the first year, which led the NPVs to negative

values at the beginning. Then, the cumulative NPVs increased gradually along with the generation of annual profits over the plant’s lifetime. All scenarios were profitable with positive

U

NPVs at discount rates lower than 10% (See Figure 3). The quality of investment can be

N

reflected by increasing the discount rate, which in turn denotes the extent of risk or uncertainty

A

that the investment is able to bear. Scenario III was the most economically favourable option

M

since the NPV at the end of a plant’s lifetime remains positive at a relatively high discount rate

PT

3.5. Sensitivity analysis

ED

(< 88.0%), whereas Scenario II and Scenario III had an IRR of 14.7% and 34.5%, respectively.

The techno-economic model was built mainly based on the findings reported in literatures and

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the information provided by industrial partners. Considering the uncertainty in technology and fluctuation in economic environment, it is necessary to identify which factor has the highest

A

impact on plant’s economics by sensitivity analysis as a part of investment risk assessment. As shown in Figure 4, the price of sugar syrups is the largest determinant of the NPV across all the scenarios. The NPVs even became negative after a 25% price reduction in Scenario I (see Figure 4). It can be explained by the fact that the sugar syrups were the main revenues across all scenarios based on the distributions shown in Table 5. However, it is not expected to pose a

24

great risk to the plant in view of the increasing demand for the bio-based products derived from these sugar syrups in the next 5-10 years. A number of reports predict that the market share in bio-based PET and PEF plastics will witness annual growth rates above 44% by 2023 due to increasing consumer demand for environmentally-friendly products (Global Market Insights, 2016). Correspondingly, fructose syrup as the feedstock for bio-based PET and PEF plastics

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production is expected to experience high market demand. The HFS-42 which currently accounts for 15% of global food sweetener usage already reached US$3,083 million in 2015

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by serving as a cheap substitute for sucrose in the food and beverage industry. This will

continue to drive the growth of the global market with an estimated rate of 4% per year (Mordor Intelligence, 2017). Regarding glucose-rich syrup, although it is currently not available in the

U

commercial sector, the increasing awareness of health and environmental protection among

N

consumers encourages usage of bio-based chemicals which is projected to grow from

A

4.5 million MT in 2015 to 8.5 million MT by 2023. It will positively influence the fermentation

M

industry where sugars are the main carbon sources for various fermentation products. Owing

ED

to the growing world population and the associated ecological problems caused by intensive farming (FAO, 2017; Ramankutty & Rhemtulla, 2012), the demand for sugars for human

PT

ingestion and awareness of environmental protection will shift the commercial interest toward other possible sources such as the waste-derived sugar syrups proposed in this study (Global

CC E

Market Insights, 2016). In view of this, it is believed that the price of sugar syrups should

A

steadily increase in the future and improve the economic performance for all scenarios.

Capital cost is the second most significant determinant in the NPVs for all scenarios (see

Figure 4). In spite of the positive NPVs remaining at a ±50% variation of the capital cost, the plant should fully utilise its processing capacity in order to make good capital investments and avoid a capacity limitation on commercial growth (Kumar et al., 2018). The breakeven charts

25

for the plant are shown in Figure 5, where the effect on costs and revenues is illustrated at different processing capacity. As described in Peters (2003), downtime is unavoidable because routine maintenance must be allowed periodically and certainly sometimes it can be caused by various operational errors such as equipment failure, power supply blackouts and insufficient raw materials. A prolonged period for the equipment to stand idle wastes capital investment

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and decrease the profitability of the plant, since the entire production process is stopped.

Therefore, the breakeven point was investigated in order to find out the critical processing

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capacity. In Figure 5, the breakeven points are shown to be 67%, 48% and 28% in Scenarios I,

II and III, respectively. This means the plant should process no less than 134,148 MT (Scenario I), 96,106 MT (Scenario II), and 56,061 MT (Scenario III) of F&B waste per year in

U

order to generate profit. Definitely, collection of sufficient F&B waste is not a problem given

A

M

for the benefit of long-term profitability.

N

that one-third of food is wasted worldwide but the plant should also operate at its full capacity

ED

4. Conclusions

This study proposed integrated biorefinery for valorisation of F&B waste, which is proven to

PT

be technically and economically feasible. The returns on investment are satisfactory for the production of fructose syrup (9.4%), HFS-42 (22.8%) and glucose-rich syrup (58.9%). The

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sugar syrups have high cost competitiveness with relatively low net production costs and minimum selling prices. This study motivated the current industrial practice through providing

A

a significant techno-economic basis for the development of innovative F&B waste treatment. It should be admitted here that sugar recovery and its potential applications are also of interest for valorisation of starch-based waste and lignocellulosic biomass, where 100.8 g/L glucose from leftover food in restaurant, 44.8 g/L glucose and 9.7 g/L xylose from agricultural waste including sugarcane bagasse, wheat straw and corn stalk can be recovered based on our recent

26

study (Li et al., 2018). Hence, the process developed does not only allow biorefinery development in the F&B industry, but can also be applied to other feedstocks which are industrially relevant.

Furthermore, wastewater problem could be solved in future through innovative purification

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process such as the novel use of biochar which is currently under investigation by our research team using textile wastewater. Therefore, the purified water can then be reused in order to

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reduce the operating cost, which can also benefits the environmental sustainability of the

N

U

overall process.

A

Declaration

M

Consent for publication

PT

Competing interests

ED

All authors have approved the manuscript to be published.

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The authors declare no conflict of interest.

Funding

A

This work was supported by the Industrial Technology Funding from the Innovation and Technology Commission (ITP/087/15TP) in Hong Kong.

Acknowledgements The authors acknowledge the Innovation and Technology Funding (ITP/087/15TP) from the

27

Innovation and Technology Commission in Hong Kong. We would also like to thank PepsiCo and Novozymes® for providing industrial sponsorship. The authors are grateful to Mr. Ernest Ming from Eco-Nutrient Biotechnology Limited Company and Mr. Roberto Vazquez from ASB Biodiesel (Hong Kong) Ltd. for providing the prices of insect feed and lipids. Special thanks are dedicated to Dr. ir. Hendrik Waegeman and Ir. Emile Redant at Bio Base Europe

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Pilot Plant in Belgium for providing professional consultancy and sharing their industrial

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experience.

Disclaimer

The views expressed in this manuscript are those of the authors and do not necessarily reflect

A

N

U

the position or policy of PepsiCo Inc.

1.

M

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economic analysis of a food waste valorization process via microalgae cultivation and coproduction of plasticizer, lactic acid and animal feed from algal biomass and food waste, Bioresource Technology 198, 292-299. 32. Kwan, T.H., Ong, K.L., Haque, M.A., Kwan, W.H., Kulkarni, S., Lin, C.S.K., 2018a. Valorisation of food and beverage waste via saccharification for sugars recovery,

IP T

Bioresource Technology 255, 67-75.

33. Kwan, T.H., Ong, K.L., Haque, M.A., Tang, W., Kulkarni, S., Lin, C.S.K. 2018b. High

SC R

fructose syrup production from mixed food and beverage waste hydrolysate at laboratory and pilot scales. Food and Bioproducts Processing 111, 141-152.

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34. Kwan, T.H., Hu, Y., Lin, C.S.K., 2018c. Techno-economic analysis of a food waste

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valorisation process for lactic acid, lactide and poly(lactic acid) production, Journal of

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Cleaner Production 181, 72-87.

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35. Lameloise, M.-L., Matinier, H., Fargues, C. 2009. Concentration and purification of malate ion from a beverage industry waste water using electrodialysis with homopolar

ED

membranes. Journal of Membrane Science, 343(1), 73-81. 36. Lameloise, M.-L., Lewandowski, R. 2012. Recovering l-malic acid from a beverage

PT

industry waste water: Experimental study of the conversion stage using bipolar membrane

CC E

electrodialysis. Journal of Membrane Science, 403-404, 196-202. 36. Li, C., Ong, K.L., Yang, X., Lin, C.S.K. 2018. Bio-refinery of waste streams for green and efficient SA production by engineered Yarrowia lipolytica without pH control. (under

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37. Lin, C.S.K., Koutinas, A.A., Stamatelatou, K., Mubofu, E.B., Matharu, A.S., Kopsahelis, N., Pfaltzgraff, L.A., Clark, J.H., Papanikolaou, S., Kwan, T.H., Luque, R., 2014. Current and future trends in food waste valorization for the production of chemicals, materials and fuels: a global perspective, Biofuels, Bioproducts and Biorefining 8(5), 686-715. 32

38. Lin, C.S.K., Ming, Y.H., Kwan, T.H., 2017. Method of converting an organic waste and its product and use of the product. Hong Kong. Patent no.: 17101289.9; The People Republic of China. Patent no.: 201710067687.4 39. Maurer, V., Holinger, M., Amsler, Z., Früh, B., Wohlfahrt, J., Stamer, A., & Leiber, F. 2016. Replacement of soybean cake by Hermetia illucens meal in diets for layers. Journal of

IP T

Insects as Food and Feed, 2(2), 83-90.

40. Mohan, S.V., Nikhil, G.N., Chiranjeevi, P., Reddy, C.N., Rohit, M.V., Kumar, A.N., Sarkar,

SC R

O., 2016. Waste biorefinery models towards sustainable circular bioeconomy: critical review and future perspectives. Bioresource technology 215, 2-12.

U

41. Mordor Intelligence, 2017. High fructose corn syrup market - growth, trends, and forecast

2013.

Enzymes

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42. Novozymes,

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market. (Accessed 18th January, 2018).

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(2017 - 2022). www.mordorintelligence.com/industry-reports/high-fructose-corn-syrup-

at

work. www.novozymes.com/en/-

18th January, 2018).

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/media/Novozymes/en/about-us/brochures/Documents/Enzymes_at_work.pdf (Accessed

PT

43. Novozymes, 2016. Personal communication via email with Isbak N. (Business Development Manager in Novozymes). “Re: Starbucks/PepsiCo opportunity.” Message

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to Kwan Tsz Him and Dr Carol Lin Sze Ki. 9th August, 2016.

44. Peters, M., K. Timmerhaus and R. West, 2003. Plant design and Economics for Chemical

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Engineers. Boston, McGraw-Hill.

45. Pleissner, D., Lam, W.C., Han, W., Lau, K.Y., Cheung, L.C., Lee, M.W., Lei, H.M., Lo, K.Y., Ng, W.Y., Sun, Z., Melikoglu, M., Lin, C.S.K., 2014a. Fermentative polyhydroxybutyrate production from a novel feedstock derived from bakery waste, BioMed Research International 2014, 1-8. 33

46. Pleissner, D., Lam, W.C., Sun, Z., Lin, C.S.K., 2013. Food waste as nutrient source in heterotrophic microalgae cultivation, Bioresource Technology 137, 139-146. 47. Pleissner, D., Lau, K.Y., Zhang, C., Lin, C.S.K., 2015. Plasticizer and surfactant formation from food‐waste-and algal biomass‐derived lipids. ChemSusChem 8(10), 1686-1691.

IP T

48. Pleissner, D., Schneider, R., Venus, J., Koch, T., 2017. Separation of lactic acid and recovery of salt‐ions from fermentation broth. Journal of Chemical Technology and

SC R

Biotechnology 92(3), 504-511.

49. Quested, T., Ingle, R., Parry A., 2013. Household food and drink waste in the United Kingdom 2012. WRAP.

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Ecology and the Environment 10(9), 455-455.

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50. Ramankutty, N., & Rhemtulla, J., 2012. Can intensive farming save nature? Frontiers in

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51. Ramírez, E. C., Johnston, D. B., McAloon, A. J., Singh, V., 2009. Enzymatic corn wet

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milling: engineering process and cost model. Biotechnology for biofuels 2(1), 2.

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52. Ramirez, E. C., Johnston, D. B., McAloon, A. J., Yee, W., Singh, V., 2008. Engineering process and cost model for a conventional corn wet milling facility. Industrial Crops and

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products 27(1), 91-97.

53. Ulrich, G.D., 1984. A guide to chemical engineering process design and economics, Wiley,

CC E

New York.

54. United States Department of Agriculture Economic Research Service (USDA), 2017b.

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Sugar and Sweeteners Yearbook Tables, Table 7-U.S. wholesale list price for glucose syrup, Midwest markets, monthly, quarterly, and by calendar and fiscal year. https://www.ers.usda.gov/data-products/sugar-and-sweeteners-yearbook-tables.aspx (Accessed 10th January, 2018)

55. United States Department of Agriculture Economic Research Service (USDA), 2017a. 34

Sugar and Sweeteners Yearbook Tables, Table 9-U.S. price for high fructose corn syrup (HFCS), Midwest markets, monthly, quarterly, and by calendar and fiscal year. https://www.ers.usda.gov/data-products/sugar-and-sweeteners-yearbook-tables.aspx (Accessed 10th January, 2018) 56. Ventura, E.E., Davis, J.N., Goran, M.I., 2011. Sugar content of popular sweetened

IP T

beverages based on objective laboratory analysis: focus on fructose content. Obesity 19(4), 868-874.

SC R

57. Vink, E.T., Davies, S., 2015. Life cycle inventory and impact assessment data for 2014 Ingeo™ polylactide production. Industrial Biotechnology 11(3), 167-180.

U

58. White, J. S., 2014. Sucrose, HFCS, and fructose: history, manufacture, composition,

N

applications, and production, in: Rippe, J.M. (Eds.), Fructose, High Fructose Corn Syrup,

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Sucrose and Health. Springer New York, pp. 13-33.

M

59. Yu, I.K.M., Ong, K.L., Tsang, D.C.W., Haque, M.A., Kwan, T.H., Chen, S.S., Uisan, K., Kulkarni, S., Lin, C.S.K., 2018. Chemical transformation of food and beverage waste-

ED

derived fructose to hydroxymethylfurfural as a value-added product. Catalysis Today In

A

CC E

PT

press (DOI: 10.1016/j.cattod.2018.01.011).

35

Figure captions

Figure 1. Production process scheme in different scenarios.

IP T

Figure 2. Cost distribution of the operating cost in different scenarios.

Figure 3. Cumulative cash flow diagrams at different discount rate in (a) Scenario I, (b)

SC R

Scenario II and (c) Scenario III.

U

Figure 4. Sensitivity analysis of (a) Scenario I, (b) Scenario II and (c) Scenario III.

A

CC E

PT

ED

M

A

N

Figure 5. Breakeven chart for (a) Scenario I, (b) Scenario II and (c) Scenario III.

36

A ED

PT

CC E

IP T

SC R

U

N

A

M

Figure 1.

37

A ED

PT

CC E

IP T

SC R

U

N

A

M

Figure 2.

38

A ED

PT

CC E

IP T

SC R

U

N

A

M

Figure 3.

39

40

A ED

PT

CC E

IP T

SC R

U

N

A

M

A ED

PT

CC E

IP T

SC R

U

N

A

M

Figure 4.

41

42

A ED

PT

CC E

IP T

SC R

U

N

A

M

A ED

PT

CC E

IP T

SC R

U

N

A

M

Figure 5.

43

44

A ED

PT

CC E

IP T

SC R

U

N

A

M

Table 1. Parameters for the techno-economics study Estimation assumption Hong Kong 200,221 MT of mixed food and beverage waste year-1 0.95 (346 days year-1) Mixed food and beverage waste Scenario I: Fructose syrup Scenario II: HFS-42 Scenario III: Glucose-rich syrup

Mass balance Saccharification duration Solid-to-liquid ratio in saccharification Hydrolysis yield in saccharification Service volume of adsorption Working lifetime of adsorption resin Lifetime of isomerase Fructose content after isomerisation Fructose separation efficiency in SMB

SC R

U

Capital cost = FCI + working capital

CC E

PT

Annual operating cost

A

Total variable production costs Raw materials Labour-dependent Utility cost

Wastewater treatment

A

N

Listed equipment purchase cost Equipment specific 0.31 × PC 0.43 × PC 0.10 × PC 0.15 × PC 0.12 × PC 0.55 × PC

M

ED

Capital cost Direct Cost (DC) Equipment purchase cost (PC) Installation Process piping Instrumentation Electrical Buildings Yard improvement Service facilities Indirect Cost (IC) Engineering and supervision Construction expenses Legal expenses Constractor's fee Contingency Fixed-capital investment (FCI) Working capital

12 hours 70% (w/v) 95% 25 bed volumes 2,000 hours 1 year 42-45% 41% by mass of fructose

IP T

Items Plant location Plant capacity Design on-stream factor Feedstock Main products

0.32 × PC 0.34 × PC 0.04 × PC 0.19 × PC 0.37 × PC FCI = DC + IC 0.15 × FCI Annual operating cost = total variable production costs + fixed charges + plant overhead costs + general expenses From mass balance No. of operator was calculated by Ulrich et al., 1984 Annual salary: US$20,000 Supervision factor: 0.15 Electricity: US$0.122 kWh-1 Steam: US$12 MT-1 Process water: US$0.12 m-3 Cooling water: US$0.03 m-3 US$0.4 MT-1

45

US$25 MT-1 food waste powder 7 % of the FCI 15 % of the total labour cost 15 % of the equipment maintenance and repair cost 4 % of the capital cost

Logistic cost Equipment maintenance and repair Laboratory cost for QC and QA Operating supplies Royalties Fixed charges Depreciation (20-year straight line) Insurance Plant overhead costs General expenses Administrative costs Distribution and marketing costs Research and development costs

M

A

N

US$935 MT-1 US$623 MT-1 US$755 MT-1 US$500 MT-1 US$65 MT-1 US$77 MT-1

U

Revenues Selling price of fructose syrup Selling price of HFS-42 Selling price of glucose-rich syrup Selling price of lipids Selling price of animal feed Food waste treatment service fee

SC R

15 % of operating labour cost No less than 2 % of total operating cost 5 % of annual operating cost

IP T

Depreciated 5 % of the FCI 1 % of the FCI 50 % of labour, equipment maintenance and repair costs

Table 2 Overall component balance of the process in a year (MT year-1) Component

Scenario 2

ED

Scenario 1 Input

Output

117,196

0

83,000

0

Glucoamylase

830

Sucrase

28

Scenario 3

Input

Output

117,196

0

83,000

0

0

-830

830

0

-28

Output - Input 117,196

Output – Input 117,196

Input

Output

117,196

0

-83,000

83,000

0

-83,000

0

-830

830

0

-830

28

0

-28

28

0

-28

-83,000

Lipids

0

14,168

14,168

0

14,168

14,168

0

14,168

14,168

NaOH

2,284

0

-2,284

2,284

0

-2,284

1,559

0

-1,559

H2SO4

4,734

0

-4,734

4,734

0

-4,734

2,892

0

-2,892

Methanol#

5,039

4,787

-252

5,039

4,787

-252

5,039

4,787

-252

0

274,373

274,373

0

274,373

274,373

0

176,848

176,848

284,275

67,308

216,967

189,572

67,562

131,329

A

CC E

PT

Mixed Beverage Waste Mixed Food Waste

Output - Input 117,196

Waste water Water

1,538,825

1,321,858

216,967

Remaining solids*

0

63,246

63,246

0

63,246

63,246

0

63,246

63,246

Retentate*

0

24,070

24,070

0

24,070

24,070

0

24,070

24,070

Precipitate*

0

797

797

0

797

797

0

797

797

Sugar syrups

0

48,638

48,638

0

48,638

48,638

0

48,638

48,638

Total

1,751,937

1,751,937

0

497,387

497,387

0

400,116

400,116

0

46

A

CC E

PT

ED

M

A

N

U

SC R

IP T

* Values are based on wet weight. # Methanol was used as a reagent for regeneration of adsorption and ion exchange columns. As mentioned in Section 2.2.2, it is assumed that 95% of methanol is recovered by the distillation column.

47

Table 3. Fixed-capital investment (FCl) of the plant. Cost (US$) Unit (US$)

price Scenario I

Scenario III

Cost Quantity (US$)

Quantity

Cost (US$)

2,000

1

2,000

1

2,000

1

2,000

Saccharification tank (R-101)

57,255

13

853,313

13

853,313

13

853,313

Centrifuge (DS-101)

692,000

0

0

1

692,000

0

0

Heating (HX-102)

3,000

1

3,000

1

3,000

1

3,000

Storage (V-101)

50,834

1

50,834

1

50,834

1

Centrifuge (DS-102)

692,000

1

692,000

1

692,000

1

Filtration (DF-101)

219,000

2

438,000

2

438,000

2

Adsorption (GAC-101)

1,350,000

2

2,700,000

2

Distillation column (EV-101)

736,575

1

736,575

1

Ion exchange (INX-101)

882,000

3

2,646,000

3

Heating (HX-103)

2,000

0

0

1

Isomerisation (PFR-101)

208,000

2

416,000

2

Ion exchange (INX-102)

1,377,000

3

4,131,000

Evaporator (EV-102)

913,000

SC R

50,834

692,000 438,000

2

2,700,000

736,575

1

736,575

2,646,000

3

2,646,000

2,000

0

0

416,000

0

0

3

4,131,000

0

0

U

2,700,000

913,000

0

0

0

0

1

2,602,000

0

0

0

0

1

6,179,000

0

0

0

0

Evaporator (EV-104)

1,582,000

1

1,582,000

0

0

0

0

Evaporator (EV-105)

772,000

0

0

1

772,000

0

0

Evaporator (EV-106)

791,000

0

0

0

0

1

791,000

37

23,944,722 37

14,134,722 27

8,912,722

N/A

7,289,117

N/A

4,484,517

N/A

2,779,517

N/A

7,422,864

N/A

4,381,764

N/A

2,762,944

N/A

10,296,230 N/A

6,077,930

N/A

3,832,470

N/A

2,394,472

N/A

1,413,472

N/A

891,272

N/A

3,591,708

N/A

2,120,208

N/A

1,336,908

N/A

2,873,367

N/A

1,696,167

N/A

1,069,527

Service facilities

N/A

13,169,597 N/A

7,774,097

N/A

4,901,997

Engineering and supervision

N/A

7,662,311

N/A

4,523,111

N/A

2,852,071

Construction expenses

N/A

8,141,205

N/A

4,805,805

N/A

3,030,325

Legal expenses

N/A

957,789

N/A

565,389

N/A

356,509

Contractor’s fee

N/A

4,549,497

N/A

2,685,597

N/A

1,693,417

Contingency

N/A

8,859,547

N/A

5,229,847

N/A

3,297,707

Installation

Electrical Buildings

A

CC E

Yard improvement

PT

Process piping Instrumentation

M

ED

Total

N

1

Simulated moving bed system 2,602,000 (SMB-101) Evaporator (EV-103) 6,179,000

A

Equipment purchase costs* Heating (HX-101)

IP T

Scenario II

Cost Quantity (US$)

Items

Total

101,152,427

* Equipment code can be referred to Figure 2, 3 and 4.

48

59,892,627

37,717,387

I N U SC R

Table 4. Annual operating cost and net production cost for Scenario I, Scenario II and Scenario III.

MT MT MT MT MT

A

CC E

Total Labour-Dependent Operating labour Operating supervision Total Utilities Electricity Steam Process water Cooling water Total Waste water treatment Logistic cost Operating supplies Royalties Laboratory/QC/QA Maintenance & repair Depreciation Insurance Plant overhead costs

M

2,284 4,734 252 830 28

43.0 19.0 3.5 5.1 4.8

20,000

5,791 456,143 41,990 41,990 500,000

Cost (US$)

685,323 890,083 123,456 4,980,000 705,500 7,384,362

Scenario II Cost contribution Quantity Unit (US$/MT-1) 2,284 4,734 252 830 28

A

300 188 490 6000 25000

PT

Raw materials Sodium hydroxide Sulphuric acid Methanol Glucoamylase Sucrase Total Consumables Isomerase Lewatit VP OC 1064 MD PH resin Dowex monosphere 88 resin Dowex monosphere 66 resin Dowex monosphere 99 Ca/320 resin

Unit

ED

Items

Scenario I Unit Cost (US$/unit) Quantity

kg L L L L

35

0.122 12 0.12 0.03

2,820,257 640,934 216,967 466,460

kWh-1 MT MT MT

0.4 25.0

274,373 200,221

MT MT

152

248,997 8,685,393 148,645 213,309 2,390,000 11,686,344 240

5,791 456,143 11,192 11,192 0

698,880 104,832 803,712

33

706,148 7,691,212 27,012 12,268 8,073,262 109,749 5,005,523 1,062,100 4,653,012 120,557 7,080,670 5,057,621 1,011,524 3,942,191

MT MT MT MT MT

kg L L L L

49

685,323 890,083 123,456 4,980,000 705,500 7,384,362 248,997 8,685,393 39,620 56,855 0 9,030,865 665,280 99,792 765,072

17

166 2 103 22 96 2 146 104 21 81

Scenario III Cost Cost (US$) contribution Quantity Unit (US$/MT-1)

2,515,647 47,650 216,753 466,460

kWh-1 MT MT MT

274,373 200,221

MT MT

305,748 571,804 26,986 12,268 916,805 109,749 5,005,523 628,873 2,755,061 114,761 4,192,484 2,994,631 598,926 2,478,778

1,559 2,892 252 830 28

MT MT MT MT MT

152 0 456,143 5,596 5,596 0

kg L L L L

186 29 16

19 2 93 13 57 2 86 62 12 51

2,515,647 47,750 122,010 466,460

kWh-1 MT MT MT

176,848 200,221

MT MT

Cost (US$)

Cost contribution (US$/MT-1)

467,846 543,628 123,456 4,980,000 705,500 6,820,430

140

0 8,685,393 19,810 28,428 0 8,733,631

180

581,280 87,192 668,472

14

305,748 572,999 15,190 12,268 906,205 70,739 5,005,523 396,033 1,735,000 100,271 2,640,217 1,885,869 377,174 1,654,345

19 1 103 8 36 2 54 39 8 34

I N U SC R 104,832 1,500,000 3,000,000

Administrative costs Distribution and marketing costs Research and development costs Total Credit for sale of by-products

99,792 1,500,000 2,000,000

2 31 41

87,192 1,500,000 1,800,000

2 31 37

60,595,458 1,246

40,575,681 834

34,381,099 707

7,084,050 146 5,727,332 118 15,417,009 317

7,084,050 146 5,727,332 118 15,417,009 317

7,084,050 146 5,727,332 118 15,417,009 317

665

517

443

A

Lipids Insect feed Food waste treatment service fee *Net production cost (US$ MT-1)

2 31 62

M

*Net production cost was calculated with reference to Peters (2003).

Table 5. Utilities usage and cost in the processes Steam (MT)

Process water (MT)

Cooling water (MT)

Mixing Heating Saccharification Centrifuge Mixing Heating Storage Centrifuge Filtration Total Cost (US$)

1,975,400 248,834 248,834 42,579 2,515,647 305,748

6,557 2,407 8,964 107,568

29,050 29,050 3,617

0 0

Adsorption Distillator Ion exchange Ion exchange Total Cost (US$)

0 0

5,212 5,212 62,549

11,801 148,653 94,703 255,157 31,767

466,460 466,460 12,268

Mixing Heating Isomerisation Total

0

5,395 5,395

0

0

ED

Electricity (kWh)

CC E

Saccharification MX-101 HX-101 R-101 DS-101 MX-102 HX-102 V-101 DS-102 DF-101

Equipment

PT

Item code*

A

Purification GAC-101 EV-101 INX-101 INX-102

Isomerisation MX-104 HX-103 PFR-101

50

I N U SC R A

0

64,740

0

0

304,610 304,610 37,022

64,798 449,511 514,310 6,171,714

1,247,490 -1,024,137 223,353

0 0

0 0 2,820,257 342,770 2,515,647 305,748 2,515,647 305,748

112,448 28,079 33,574 174,101 2,089,212 640,934 7,691,212 47,650 571,804 47,750 572,999

-297,721 -67,522 -67,562 -432,805 -51,937 216,967 27,012 216,753 26,986 122,010 15,190

0 0 466,460 12,268 466,460 12,268 466,460 12,268

A

CC E

PT

ED

M

Cost (US$) Glucose-fructose separation EV-102 Evaporator MX-105 Mixing SMB-101 Simulated moving bed system EV-103 Evaporator Total Cost (US$) Sugar syrup evaporation EV-104 Evaporator EV-105 Evaporator EV-106 Evaporator Total Cost (US$) Consumption in Scenario I Cost in Scenario I (US$) Consumption in Scenario II Cost in Scenario II (US$) Consumption in Scenario III Cost in Scenario III (US$)

Table 6. Annual revenue and profitability indicators of Scenario I, II and III. Scenario I Items

Unit price Quantity (MT) (US$/unit)

Scenario II Value

Percentage (%) Quantity (MT)

51

Scenario III Value

Percentage (%) Quantity (MT)

Value

Percentage (%)

I N U SC R

73,725,592

100

58,521,389

100

64,951,932

100

935

48,638

45,497,201

62

N/A

N/A

N/A

N/A

N/A

N/A

HFS-42

623

N/A

N/A

N/A

48,638

30,292,998

52

N/A

N/A

N/A

Glucose-rich syrup

755

N/A

N/A

N/A

N/A

N/A

N/A

48,638

36,723,541

57

Lipids

500

14,168

7,084,050

10

14,168

7,084,050

12

14,168

7,084,050

11

Insect feed

65

88,113

5,727,332

8

88,113

5,727,332

10

88,113

5,727,332

9

77

200,221

15,417,009

21

200,221

15,417,009

26

200,221

15,417,009

24

treatment

Gross profit (US$ year-1)

ED

Food waste service fee

M

Fructose syrup

A

Revenue (US$/year)

13,130,134

17,945,708

30,570,833

10,963,662

14,984,666

25,526,646

Net present value (× 1,000 US$)

92,470

157,393

293,572

Internal rate of return (%)*

14.7

34.5

88.0

Return on investment (%)

9.4

22.8

58.9

Payback time (year)*

10.2

5.8

2.3

Minimum selling price (US$ MT-1)

747

302

157

CC E

PT

Net profit (US$ year-1)

A

*Discount rate was set as 5 %.

52