- Email: [email protected]
Comparative Analysis of Cyclohexane Production from Benzene and Hydrogen: Via Simulation and Sustainability Evaluator Approach
Available online at www.sciencedirect.com
ScienceDirect Materials Today: Proceedings 19 (2019) 1693–1702
www.materialstoday.com/proceedings
ICCSE 2018
Comparative Analysis of Cyclohexane Production from Benzene and Hydrogen: Via Simulation and Sustainability Evaluator Approach M.R. Aliff Radzuan, S. Nursyahirah*, M. Afnan Syihabuddin, Amin Safwan Alikasturi, and T.A. Faizal Malaysian Institute of Chemical & Bioengineering Technology, Universiti Kuala Lumpur, 78000, Alor Gajah, Melaka
Abstract
Cyclohexane (C6H12) production from benzene and hydrogen is widely used in the industry. The objectives of this study were to simulate the Cyclohexane plant using process simulation software and to evaluate the sustainability of cyclohexane production. Two methods were used to achieve the objectives; simulation and sustainability evaluation. The overall sustainability impact was calculated using the formula SUI = 0.2*EI+0.4*ENVI+0.4*SCI. Two cyclohexane plants were simulated using Aspen HYSYS. The data from both simulations were extracted to be attempted in the Sustainability Evaluator (SE). SE evaluates Economics, Environmental, and Social Impacts. From the simulations, they show that plant 1 gave the highest production yield of 95% compared to plant 2 of 92.1%. The purity of the plant 1 and 2 were 99.4% and 99% in the liquid phase. The results that obtained from plant 1 and plant 2 for SE were 0.16 and 0.12 respectively. Those attempts show that the best economic, environmental, and social were from plant 2. As the conclusions, plant 1 gave the best in terms of percentage yield and plant 2 in terms of Environmental, Economic, and Social impacts of SE. © 2019 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Conference on Chemical Sciences and Engineering: Advance and New Materials, ICCSE 2018. Keywords: Cyclohexane; Aspen HYSYS; Sustainability; Environment; Economic; Social
* Corresponding author. Tel.: +6-06-551-2011; fax: +6-06-551-2001. E-mail address: [email protected] 2214-7853 © 2019 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Conference on Chemical Sciences and Engineering: Advance and New Materials, ICCSE 2018.
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1.
Introduction
Cyclohexane is also known as cycloalkane, which has the atomic formula of C6H12. It is a non-polar solvent for the chemical industry. It is used as a raw material for the industrial production of adipic acid and caprolactam, which is, both compounds were being used in the nylon production [1], which are used to manufacture nylon 6, nylon 66, and others. Nylon is the product that can be used to make a thread, which can be further transformed, to clothing and textile. While caprolactam is the primary feedstock for nylon 6 production [2]. In the industrial scale, the cyclohexane compound was existed by the reacting of benzene and hydrogen. In the lab, cyclohexane also used as a standard and for analysis. The application of cyclohexane in the industries is to produce adipic acid and caprolactam Aspen HYSYS that is readily available in the UniKL MICET is a process simulation software that is used to simulate cyclohexane plant. It also provides financial information that significant is for sustainability studies [3]. Aspen HYSYS aids the user to simulate and amend chemical plants quicker compared to the conventional way. The benefits of the Aspen HYSYS to the users are; improving the engineering design and operation, minimizing the capital and operating costs, as well as reducing the energy and time consumption. Sustainability was said to the standard of the life during a community whether the social, economic and environmental system that structures the community are providing a productive, healthy, significant life for all community residents, gift and future [4]. The understanding of sustainability has evolved within the last twenty-five years since the Brundtland Commission [5]. Based on Fig. 1, the actions to enhance the conditions during a sustainability community consider these connections. Understanding the three components and their links is essential to understanding sustainability, as a result of sustainability is concerning quite merely quality of life. It is regarding understanding the connections between and achieving balance among the social, environmental, and economic items of the community [4]. Defining sustainability is consequently not easy, as it is a broad and deep conception that depends on several factors. To produce a basis for understanding sustainability, and the subsequent challenge in creating indicators, it is vital to know the most accepted definition of sustainable development [5].
Fig. 1: Community links among its three parts [4].
M.R.A. Radzuan et al. / Materials Today: Proceedings 19 (2019) 1693–1702
2.
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Methodology
The methodologies of this research project are of simulation and evaluation. The simulation was done using process simulation, also known as Aspen HYSYS, whilst the sustainability evaluation was done using Sustainability Evaluator (SE). 2.1 General Method There are three steps for this research project. The first step is to select two base cases of the production of cyclohexane to be simulated in the Aspen HYSYS. The operating parameters for this simulation were extracted from the literature reviews. Next, the own-developed SE was used to evaluate the impacts of economic, environmental, and social from the production of cyclohexane. The last step is to identify the best production of cyclohexane based on the sustainability impact. 2.2 Aspen HYSYS There were two plants of cyclohexane production from hydrogen and benzene simulated using Aspen HYSYS software. The first step was to specify all of the components involved in the simulation, including reactant, product, by-product, utilities, and waste. Second, the suitable fluid package, also known as thermodynamic packaged, was chosen based on the production. Next step was to specify the reaction set by identified the stoichiometry of the reaction. Next phase is to start with the simulation by selecting the unit operation involves such as compressor, reactor, column, valve, and many more. The final step was to generate the consolidated report to compare them with the manual calculation. 2.3 Sustainability Evaluator (SE) The own-established SE was used as a tool to evaluate the process for sustainability. The score for each evaluation is generated from the scorecard [16]. This tool used the designated metrics and indices that address health, environmental, economic, and safety issues. The SE was developed in on the Microsoft-Excel based. The data for the SE was extracted from the report generated in Aspen HYSYS. 2.3.1.
Economic Impact
Economic sustainability is inextricably connected to both social and environmental [6]. In order to facilitate the assessment of the sustainability of entities, every entity must be responsible to its stakeholders for the results of its activities [7]. In contrast, to attain sustainability, every entity should be commended responsible to all or any its stakeholders for consequences of its actions on the setting, on society and on the economy. This economic metrics, the set that can be used to evaluate the effectiveness of the cost of a process are: product revenue, the costs of raw, material, the waste treatment costs, the operating costs, the material value added, the annualized capital costs, profit and profit relative to investment (PRI). PRI can be calculated as Eq (1) 𝑃𝑅𝐼 = 2.3.2.
× 100
(1)
Environmental Impact
When the economic impact has been made, the next step to evaluate in the evaluator is an environmental impact. The environmental impact is the possible adverse effects caused by a development, industrial, or infrastructural project or by the discharge of a substance within the surroundings. There are three types of metrics that can help to evaluate the environmental impact. The three types of metrics that involve are the metrics developed
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by Bridges to Sustainability [8], Green Metrics [9], and the Institution of Chemical Engineers [10]. Here have nine impact categories of environmental: global warming, stratospheric ozone depletion, photochemical smog, aquatic oxygen demand, atmospheric acidification, aquatic acidification, eco-toxicity to aquatic life, eutrophication, and resource usage. The last impact category in the environmental impact was resource usage. This metric has measured the efficiency of the resource were use in the chemical reactions. The categories that include in the metrics were effective mass yield, e-factor, mass intensity, atom economy, reaction mass efficiency, mass productivity, material intensity, energy intensity or fossil fuel usage and the water consumption. 2.3.3. Social Concerns Social sustainability is usually unmarked the side of sustainability, as sustainable development discussions typically specialize in the environmental or economic aspects of sustainability. Wacoss, Western Australia Council of Social services stated that the social sustainability happens once the formal and informal processes, systems, structures, and relationships actively support the capability of the current and future generations to make liveable and healthy communities [11]. This section has two sections, which is the process of safety risks and health risks. This is the process of safety risks are; the heat of main and side reaction index, flammability index, explosivity index, corrosive index, toxic exposure index, equipment process safety index, process safety index, temperature, index, and pressure index However, health metrics have eleven categories, which are; carcinogenic health risk, development health risk, reproductive health risk, cardiovascular health risk, endocrine system health risk, liver damage health risk, immune system damage health risk, kidney damage health risk, skeletal system damage health risk, neurological damage health risk, and respiratory system health risk. 2.3.4.
Health Risks
In health risks, the calculation to calculate in the environmental sustainability evaluator was the same by multiplying the mass flow rate of each of the components from the waste stream by its score in the scorecard [16]. 3.
Result and discussion
3.3. Cyclohexane Hydrogenation Process Cyclohexane was used to create cyclohexanol and cyclohexanone, which is, in turn, were used in the main as precursors for the assembly of adipic acid and caprolactam, respectively. Cyclohexane was used for the various solvent of the applications and used for the production of cyclohexanone and cyclohexanol for the non-precursor user. As the result of cyclohexane’s intrinsic link to the polymer chain and its use in cars, construction, and textiles. The world cyclohexane demand remains powerfully influenced by economic conditions. Cyclohexane is basically consumed for nylon half dozen fibers, resins, and films [13]. Generally, benzene hydrogenation was an exothermic reaction process, so the operation condition for the conversion reactor that needs to be maintained at the temperature between 165°C to 320°C to initiate the reaction [14]. Then, the temperature range of the reactor for cyclohexane plant was between 2000 – 3000 kPa [14]. The following reaction that takes place in the reactor was: 𝐶 𝐻 + 3𝐻 → 𝐶 𝐻 3.3.1.
Comparison between Cyclohexane Plant 1 and Plant 2.
Table 1 shows the comparison of the specifications that had been listed in the table for both cyclohexane plants. In the method of the production of cyclohexane by the hydrogenation of benzene was worked at the inlet pressure within the mixer at 3823 kPa for both plants. Theoretically, the range of the inlet pressure that often used in the
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mixer was 2000 kPa to 3000 kPa. Besides, both of the cyclohexane plants were used the inlet temperature and total fresh mass flow at the same value, which is at 37.85°C and 30000 kg/hr respectively. This was because of it easy to compare the mass flow out of the product at the end of the simulation. From the result that obtained from both plants, it shows that the total mass flow out for cyclohexane plant 1 has a higher mass flow rate than cyclohexane plant 2, which were 28480 kg/hr and 27630 kg/hr. This is because it is due to the different root of both plants, where the first plant undergoes the recycled process, but the second plant does not experience the recycled process. The percentage yield from both of the cyclohexane plant was 95% and 92.1%. This shows that the plant that has a higher percentage yield was cyclohexane plant 1. The purity for both cyclohexane plant 1 (Fig. 2) and plant 2 (Fig. 3) were 99.4% and 99% in the liquid phase, respectively. Table 1: Operating conditions for both plants of Cyclohexane Specifications
Cyclohexane Plant 1
Cyclohexane Plant 2
Inlet Pressure (kPa)
3823
3823
Inlet Temperature (°C)
37.85
37.85
Total Fresh Mass Flow (kg/hr)
30000
30000
Total Mass flow out (kg/hr)
28480
27630
Yield (kg/hr)
28480
27630
Percentage yield (%) Purity (%)
95 99.4 (liquid phase)
92.1 99 (liquid phase)
Fig. 2: Simulation PFD of Cyclohexane Production plant 1
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Fig. 3: Simulation PFD of Cyclohexane Production Plant 2
3.4. Cyclohexane Production Process Using Sustainability Evaluator Sustainability evaluator in this research can calculate the index number for the most sustainable chemical plants. Sustainability evaluator can be used to make a comparison between two chemical plants based on their process and the different roots of the production. In this study, there were two different roots for producing cyclohexane plants, which was plant one undergoes recycle, meanwhile plant two does not recycle. Here, the objective of having the sustainability evaluator was to select the most sustainable cyclohexane plants. Two Cyclohexane Production were simulated on Aspen HYSYS. The production rate that has set on both processes were 30 000 kg/hr and purity of both processes that obtained were 99.4% and 99% in the liquid phase. Two plants were evaluated in terms of economics, environmental, and social concerns. The capital cost and utility cost were evaluated using Aspen HYSYS. Both of the results attempted in the sustainability evaluator. The value of raw materials, products, by-products, utilities, and cost of water treatment are shown in Table 2. Table 2: Summary of Economic Data for Cyclohexane Process
Item Benzene
Cost ($) $0.33/kg
References (Sinnott, 2005)
Hydrogen
$10/kg
(Air Products offers H2 at $10 per kilogram | News | gasworld, 2005)
Electricity
$0.36/kWh
(Tariff & Icpt – Tenaga Nasional Berhad, 2018)
Cyclohexane
$0.58/kg
(Chemicals A-Z, 2006)
Process Water
$0.00067/kg
(Turton.R, Bailie R., Whiting J., 2009)
Waste Treatment
$0.2/kg
(Turton.R, Bailie R., Whiting J., 2009)
Capital Recovery Factor
0.1175
The economic evaluation results of two Cyclohexane production were shown in Table 3. The profit for cyclohexane plant 1 was $59.7 million, and for cyclohexane plant 2 was $60.5 million. The profit difference for both plants were $0.8. However, Cyclohexane plant 1 has higher operating costs and capital costs, which was $6.97 and $5.10, respectively. This is because cyclohexane plant 1 undergoes recycle, which used more equipment than cyclohexane plant 2.
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Table 3: Comparison of Economic Metrics for two Cyclohexane Plant Economic Parameters
Cyclohexane Plant 1
Cyclohexane Plant 2
Revenue
$16.1
$15.7
Operating Cost
$6.97
$1.24
Waste Treatment Costs
$0.59
$1.1
Raw Material Costs
$93.6
$93.4
Capital Costs
$5.1
$3.7
Annualized Capital Cost
$0.6
$0.4
Material Value Added
$67.9
$63.3
Profit
$59.7
$60.5
As shown in Fig. 4, there was a specific environmental impact that did not involve in this cyclohexane production. This is due to both cyclohexane plants do not have a chemical that leads to atmospheric acidification, aquatic acidification, aquatic oxygen demand, and ecotoxicity to aquatic life at the waste streams. The only environmental impact related to the process were global warming, stratospheric ozone depletion, photochemical smog depletion, and eutrophication. From the bar chart in Fig. 4, can see that cyclohexane plant 2 has the higher potential to cause global warming to the environment than cyclohexane plant 1.
Fig. 4: Results of Environmental Impacts from the Sustainability Evaluator from two Cyclohexane Plants
Social impacts were also evaluated for both processes in the sustainability evaluator. Social impacts can be categorized into 2 categories, which are a safety risk and health impact. The results of the health impact were shown in Fig. 5. The significant health risk that involves both productions of cyclohexane production plants was neurological damage and respiratory damage.
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Health Impact 3.50E+03
Tonnes/year
3.00E+03 2.50E+03 2.00E+03 1.50E+03 1.00E+03 5.00E+02 0.00E+00 Neurological Damage
Respiratory Damage
Cyclohexane Plant 1
Cyclohexane Plant 2
Fig. 5: Results of Health Impacts from Sustainability Evaluator of two Cyclohexane Plants
The safety risks assessments for both processes were compared in Table 4. The results indicate that the total inherent safety index for cyclohexane plant 1 and cyclohexane plant two were 40 and 32, respectively.
Table 4: Results of Safety Metrics from Sustainability Evaluator The output of Process Safety Evaluation Flammability Index
Cyclohexane Plant 1
Cyclohexane Plant 2
8
6
Explosiveness Index
8
8
Toxic exposure Index
4
4
Temperature Index
4
4
Pressure Index
4
4
Equipment safety Index
4
2
Inputs for the safety level of process structure
8
4
Total Inherent safety Index
40
32
3.2.1 The Selection of the More Sustainable Cyclohexane Plants Production
For the overall sustainable impact value, as shown in Table 5, cyclohexane plant 2 has a lower sustainable value, which had 0.12 compared to cyclohexane plant 1, which had a value of 0.16. Based on the result and overall sustainability impact that obtained from the sustainability evaluator, it can be concluded that cyclohexane plant 2 has the more suitable products in terms of economical, environmentally friendly and socially acceptable compared to the cyclohexane plant 1.
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Table 5: Overall Sustainability Impact from the Sustainability Evaluator for two Cyclohexane Plants
Economic Impact
4.
Cyclohexane Plant 1
Cyclohexane Plant 2
0.00
0.00
Environmental Impact
0.14
0.14
Social Impact
0.28
0.15
Sustainable Impact
0.16
0.12
Conclusion
As a conclusion, the purpose of this research project is to design a cyclohexane plant using Aspen HYSYS. It helps to save time and energy for designing a plant. Besides, it helps to find the suitable thermodynamics properties of production. This was proved that the thermodynamics fluid package that suitable to use in the production of cyclohexane in this simulation was Soave-Redlich Kwong model (SRK). Next objective was to perform the comparison between two different roots of cyclohexane plants and to evaluate both plants using sustainable evaluator. Sustainability evaluator act as a calculator that consists of economic, environmental, and social impacts. From the simulations, it can be concluded that cyclohexane plant 1 gave the highest production of the yield of 95% compared to cyclohexane plant 2 of 92.1%. The purity for both of the cyclohexane plants was 99% in the liquid phase. From the sustainability evaluator, it can be used to find the best sustainable chemical plants in terms of economic, environmental, and social impact. Based on the result that has attempted in the sustainability evaluator, the overall sustainability impact index number can be obtained from the sustainability calculator. The results for the sustainability evaluator of cyclohexane plant 1 and cyclohexane plant 2 were 0.16 and 0.12, respectively. It can be concluded that cyclohexane plant 2 has more sustainable production in terms of economical, environmentally friendly, and socially acceptable compared to the cyclohexane plant 1. Acknowledgments We would like to acknowledge and thank to everyone who had contributed to the successful completion of this project especially to Malaysian Institute of Chemical & Bioengineering Technology (UniKL MICET) to provide the software to be used during the project and Majlis Amanah Rakyat (MARA) for the financial assistance. References [1] Cyclohexane Molecule (2016). Available at: https://www.worldofmolecules.com/solvents/cyclohexane.htm (Accessed: 13 March 2018). [2] Cyclohexane Market Size & Share | Global Industry Report, 2014-2025 (2016) Aug 2017. Available at https://www.grandviewresearch.com/industry-analysis/cyclohexane-market (Accessed: 19 February 2018). [3] Claudemir Ribeiro (2018) 1270 Aspen HYSYS Product Brochure FINAL - Tutorial - Hysys. Available at: http://www.ebah.com.br/content/ABAAAeqFEAK/1270-aspen-hysys-product-brochure-final (Accessed: 13 March 2018). [4] Maureen Hart (2010) Introduction to Sustainable Development | Sustainable Measures, Sustainable Measures. Available at: http://www.sustainablemeasures.com/node/42 (Accessed: 11 September 2018).
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[5] Dekker, S. et al. (2012) ‘Indicators for Sustainability,’ Sustainable Cities International, p. 84. Available at: www.cashewstory.com. [6] Reddy, T. L. and Thomson, R. J. (2015) ‘Environmental, social and economic sustainability: Implications for actuarial science’, Actuaries Institute 2015 ASTIN, AFIR/ERM and IACA Colloquia, 61(0), pp. 1–28. [7] Van der Vorst, R, Grafe-Buckens, A & Sheate, WR (1999). A systemic framework for environmental decisionmaking. Journal of Environmental Assessment and Policy Management 1(1), 1–26 [8] Tanzil, D. and B. Beloff (2006). "Assessing Impacts: Overview on Sustainability Indicators and Metrics." Environmental Quality Management 15(4): 41-56. [9] Constable, D., D. Curzons and V. Cunningham (2002). "Metrics to 'Green' Chemistry - Which are the Best?" Green Chemistry 4(6): 521-527. [10] IChemE Metrics. (2002). "The Sustainability Metrics: Sustainable Development Progress Metrics Recommended for Use in the Process Industry." Retrieved March 1, 2010, from http://www.icheme.org/. [11] David Martin, J. H. and B. S. (2002) ‘Enhancing Indigenous Social Sustainability Through Agreements with Resource Developers’. Available at: https://www.researchgate.net/profile/David_Martin96/publication/254250492_ENHAN CING_INDIGENOUS_SOCIAL_SUSTAINABILITY_THROUGH_AGREEMENTS_WITH_RESOURCE_DEVE LOPERS/links/569ddee508aed27a702fe249/ENHANCING-INDIGENOUS-SOCIAL-SUSTAINABILITYTHROUGH-AGREEMENTS-W (Accessed: 20 October 2018). [12] Heikkila, A. (1999). Inherent Safety in Process Plant Design. An Index-Based Approach. Department of Chemical Technology Espoo, Helsinki University of Technology. Doctor of Science in Technology: 132. [13] Cyclohexane - Chemical Economics Handbook (CEH) | IHS Markit (2017) IHS Markit. Available at https://ihsmarkit.com/products/cyclohexane-chemical-economics-handbook.html (Accessed: 19 October 2018). [14] Cyclohexane production by benzene hydrogenation (2014). Available http://processflowsheet.com/cyclohexane-production-by-benzene-hydrogenation/ (Accessed: 20 March 2018).
at:
[15] Shadiya, O. O. (2013) ‘Social, Economic and Environmental Metrics for the Sustainable Optimization of Chemical and Petroleum Processes’, Journal of Chemical Information and Modeling, 53, pp. 1689–1699. doi: 10.1017/CBO9781107415324.004. [16] Anon, 2011. Scorecard Home. Scorecard Home. Available at: http://scorecard.goodguide.com/ [Accessed October 19, 2018].
ScienceDirect Materials Today: Proceedings 19 (2019) 1693–1702
www.materialstoday.com/proceedings
ICCSE 2018
Comparative Analysis of Cyclohexane Production from Benzene and Hydrogen: Via Simulation and Sustainability Evaluator Approach M.R. Aliff Radzuan, S. Nursyahirah*, M. Afnan Syihabuddin, Amin Safwan Alikasturi, and T.A. Faizal Malaysian Institute of Chemical & Bioengineering Technology, Universiti Kuala Lumpur, 78000, Alor Gajah, Melaka
Abstract
Cyclohexane (C6H12) production from benzene and hydrogen is widely used in the industry. The objectives of this study were to simulate the Cyclohexane plant using process simulation software and to evaluate the sustainability of cyclohexane production. Two methods were used to achieve the objectives; simulation and sustainability evaluation. The overall sustainability impact was calculated using the formula SUI = 0.2*EI+0.4*ENVI+0.4*SCI. Two cyclohexane plants were simulated using Aspen HYSYS. The data from both simulations were extracted to be attempted in the Sustainability Evaluator (SE). SE evaluates Economics, Environmental, and Social Impacts. From the simulations, they show that plant 1 gave the highest production yield of 95% compared to plant 2 of 92.1%. The purity of the plant 1 and 2 were 99.4% and 99% in the liquid phase. The results that obtained from plant 1 and plant 2 for SE were 0.16 and 0.12 respectively. Those attempts show that the best economic, environmental, and social were from plant 2. As the conclusions, plant 1 gave the best in terms of percentage yield and plant 2 in terms of Environmental, Economic, and Social impacts of SE. © 2019 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Conference on Chemical Sciences and Engineering: Advance and New Materials, ICCSE 2018. Keywords: Cyclohexane; Aspen HYSYS; Sustainability; Environment; Economic; Social
* Corresponding author. Tel.: +6-06-551-2011; fax: +6-06-551-2001. E-mail address: [email protected] 2214-7853 © 2019 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Conference on Chemical Sciences and Engineering: Advance and New Materials, ICCSE 2018.
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1.
Introduction
Cyclohexane is also known as cycloalkane, which has the atomic formula of C6H12. It is a non-polar solvent for the chemical industry. It is used as a raw material for the industrial production of adipic acid and caprolactam, which is, both compounds were being used in the nylon production [1], which are used to manufacture nylon 6, nylon 66, and others. Nylon is the product that can be used to make a thread, which can be further transformed, to clothing and textile. While caprolactam is the primary feedstock for nylon 6 production [2]. In the industrial scale, the cyclohexane compound was existed by the reacting of benzene and hydrogen. In the lab, cyclohexane also used as a standard and for analysis. The application of cyclohexane in the industries is to produce adipic acid and caprolactam Aspen HYSYS that is readily available in the UniKL MICET is a process simulation software that is used to simulate cyclohexane plant. It also provides financial information that significant is for sustainability studies [3]. Aspen HYSYS aids the user to simulate and amend chemical plants quicker compared to the conventional way. The benefits of the Aspen HYSYS to the users are; improving the engineering design and operation, minimizing the capital and operating costs, as well as reducing the energy and time consumption. Sustainability was said to the standard of the life during a community whether the social, economic and environmental system that structures the community are providing a productive, healthy, significant life for all community residents, gift and future [4]. The understanding of sustainability has evolved within the last twenty-five years since the Brundtland Commission [5]. Based on Fig. 1, the actions to enhance the conditions during a sustainability community consider these connections. Understanding the three components and their links is essential to understanding sustainability, as a result of sustainability is concerning quite merely quality of life. It is regarding understanding the connections between and achieving balance among the social, environmental, and economic items of the community [4]. Defining sustainability is consequently not easy, as it is a broad and deep conception that depends on several factors. To produce a basis for understanding sustainability, and the subsequent challenge in creating indicators, it is vital to know the most accepted definition of sustainable development [5].
Fig. 1: Community links among its three parts [4].
M.R.A. Radzuan et al. / Materials Today: Proceedings 19 (2019) 1693–1702
2.
1695
Methodology
The methodologies of this research project are of simulation and evaluation. The simulation was done using process simulation, also known as Aspen HYSYS, whilst the sustainability evaluation was done using Sustainability Evaluator (SE). 2.1 General Method There are three steps for this research project. The first step is to select two base cases of the production of cyclohexane to be simulated in the Aspen HYSYS. The operating parameters for this simulation were extracted from the literature reviews. Next, the own-developed SE was used to evaluate the impacts of economic, environmental, and social from the production of cyclohexane. The last step is to identify the best production of cyclohexane based on the sustainability impact. 2.2 Aspen HYSYS There were two plants of cyclohexane production from hydrogen and benzene simulated using Aspen HYSYS software. The first step was to specify all of the components involved in the simulation, including reactant, product, by-product, utilities, and waste. Second, the suitable fluid package, also known as thermodynamic packaged, was chosen based on the production. Next step was to specify the reaction set by identified the stoichiometry of the reaction. Next phase is to start with the simulation by selecting the unit operation involves such as compressor, reactor, column, valve, and many more. The final step was to generate the consolidated report to compare them with the manual calculation. 2.3 Sustainability Evaluator (SE) The own-established SE was used as a tool to evaluate the process for sustainability. The score for each evaluation is generated from the scorecard [16]. This tool used the designated metrics and indices that address health, environmental, economic, and safety issues. The SE was developed in on the Microsoft-Excel based. The data for the SE was extracted from the report generated in Aspen HYSYS. 2.3.1.
Economic Impact
Economic sustainability is inextricably connected to both social and environmental [6]. In order to facilitate the assessment of the sustainability of entities, every entity must be responsible to its stakeholders for the results of its activities [7]. In contrast, to attain sustainability, every entity should be commended responsible to all or any its stakeholders for consequences of its actions on the setting, on society and on the economy. This economic metrics, the set that can be used to evaluate the effectiveness of the cost of a process are: product revenue, the costs of raw, material, the waste treatment costs, the operating costs, the material value added, the annualized capital costs, profit and profit relative to investment (PRI). PRI can be calculated as Eq (1) 𝑃𝑅𝐼 = 2.3.2.
× 100
(1)
Environmental Impact
When the economic impact has been made, the next step to evaluate in the evaluator is an environmental impact. The environmental impact is the possible adverse effects caused by a development, industrial, or infrastructural project or by the discharge of a substance within the surroundings. There are three types of metrics that can help to evaluate the environmental impact. The three types of metrics that involve are the metrics developed
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by Bridges to Sustainability [8], Green Metrics [9], and the Institution of Chemical Engineers [10]. Here have nine impact categories of environmental: global warming, stratospheric ozone depletion, photochemical smog, aquatic oxygen demand, atmospheric acidification, aquatic acidification, eco-toxicity to aquatic life, eutrophication, and resource usage. The last impact category in the environmental impact was resource usage. This metric has measured the efficiency of the resource were use in the chemical reactions. The categories that include in the metrics were effective mass yield, e-factor, mass intensity, atom economy, reaction mass efficiency, mass productivity, material intensity, energy intensity or fossil fuel usage and the water consumption. 2.3.3. Social Concerns Social sustainability is usually unmarked the side of sustainability, as sustainable development discussions typically specialize in the environmental or economic aspects of sustainability. Wacoss, Western Australia Council of Social services stated that the social sustainability happens once the formal and informal processes, systems, structures, and relationships actively support the capability of the current and future generations to make liveable and healthy communities [11]. This section has two sections, which is the process of safety risks and health risks. This is the process of safety risks are; the heat of main and side reaction index, flammability index, explosivity index, corrosive index, toxic exposure index, equipment process safety index, process safety index, temperature, index, and pressure index However, health metrics have eleven categories, which are; carcinogenic health risk, development health risk, reproductive health risk, cardiovascular health risk, endocrine system health risk, liver damage health risk, immune system damage health risk, kidney damage health risk, skeletal system damage health risk, neurological damage health risk, and respiratory system health risk. 2.3.4.
Health Risks
In health risks, the calculation to calculate in the environmental sustainability evaluator was the same by multiplying the mass flow rate of each of the components from the waste stream by its score in the scorecard [16]. 3.
Result and discussion
3.3. Cyclohexane Hydrogenation Process Cyclohexane was used to create cyclohexanol and cyclohexanone, which is, in turn, were used in the main as precursors for the assembly of adipic acid and caprolactam, respectively. Cyclohexane was used for the various solvent of the applications and used for the production of cyclohexanone and cyclohexanol for the non-precursor user. As the result of cyclohexane’s intrinsic link to the polymer chain and its use in cars, construction, and textiles. The world cyclohexane demand remains powerfully influenced by economic conditions. Cyclohexane is basically consumed for nylon half dozen fibers, resins, and films [13]. Generally, benzene hydrogenation was an exothermic reaction process, so the operation condition for the conversion reactor that needs to be maintained at the temperature between 165°C to 320°C to initiate the reaction [14]. Then, the temperature range of the reactor for cyclohexane plant was between 2000 – 3000 kPa [14]. The following reaction that takes place in the reactor was: 𝐶 𝐻 + 3𝐻 → 𝐶 𝐻 3.3.1.
Comparison between Cyclohexane Plant 1 and Plant 2.
Table 1 shows the comparison of the specifications that had been listed in the table for both cyclohexane plants. In the method of the production of cyclohexane by the hydrogenation of benzene was worked at the inlet pressure within the mixer at 3823 kPa for both plants. Theoretically, the range of the inlet pressure that often used in the
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mixer was 2000 kPa to 3000 kPa. Besides, both of the cyclohexane plants were used the inlet temperature and total fresh mass flow at the same value, which is at 37.85°C and 30000 kg/hr respectively. This was because of it easy to compare the mass flow out of the product at the end of the simulation. From the result that obtained from both plants, it shows that the total mass flow out for cyclohexane plant 1 has a higher mass flow rate than cyclohexane plant 2, which were 28480 kg/hr and 27630 kg/hr. This is because it is due to the different root of both plants, where the first plant undergoes the recycled process, but the second plant does not experience the recycled process. The percentage yield from both of the cyclohexane plant was 95% and 92.1%. This shows that the plant that has a higher percentage yield was cyclohexane plant 1. The purity for both cyclohexane plant 1 (Fig. 2) and plant 2 (Fig. 3) were 99.4% and 99% in the liquid phase, respectively. Table 1: Operating conditions for both plants of Cyclohexane Specifications
Cyclohexane Plant 1
Cyclohexane Plant 2
Inlet Pressure (kPa)
3823
3823
Inlet Temperature (°C)
37.85
37.85
Total Fresh Mass Flow (kg/hr)
30000
30000
Total Mass flow out (kg/hr)
28480
27630
Yield (kg/hr)
28480
27630
Percentage yield (%) Purity (%)
95 99.4 (liquid phase)
92.1 99 (liquid phase)
Fig. 2: Simulation PFD of Cyclohexane Production plant 1
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Fig. 3: Simulation PFD of Cyclohexane Production Plant 2
3.4. Cyclohexane Production Process Using Sustainability Evaluator Sustainability evaluator in this research can calculate the index number for the most sustainable chemical plants. Sustainability evaluator can be used to make a comparison between two chemical plants based on their process and the different roots of the production. In this study, there were two different roots for producing cyclohexane plants, which was plant one undergoes recycle, meanwhile plant two does not recycle. Here, the objective of having the sustainability evaluator was to select the most sustainable cyclohexane plants. Two Cyclohexane Production were simulated on Aspen HYSYS. The production rate that has set on both processes were 30 000 kg/hr and purity of both processes that obtained were 99.4% and 99% in the liquid phase. Two plants were evaluated in terms of economics, environmental, and social concerns. The capital cost and utility cost were evaluated using Aspen HYSYS. Both of the results attempted in the sustainability evaluator. The value of raw materials, products, by-products, utilities, and cost of water treatment are shown in Table 2. Table 2: Summary of Economic Data for Cyclohexane Process
Item Benzene
Cost ($) $0.33/kg
References (Sinnott, 2005)
Hydrogen
$10/kg
(Air Products offers H2 at $10 per kilogram | News | gasworld, 2005)
Electricity
$0.36/kWh
(Tariff & Icpt – Tenaga Nasional Berhad, 2018)
Cyclohexane
$0.58/kg
(Chemicals A-Z, 2006)
Process Water
$0.00067/kg
(Turton.R, Bailie R., Whiting J., 2009)
Waste Treatment
$0.2/kg
(Turton.R, Bailie R., Whiting J., 2009)
Capital Recovery Factor
0.1175
The economic evaluation results of two Cyclohexane production were shown in Table 3. The profit for cyclohexane plant 1 was $59.7 million, and for cyclohexane plant 2 was $60.5 million. The profit difference for both plants were $0.8. However, Cyclohexane plant 1 has higher operating costs and capital costs, which was $6.97 and $5.10, respectively. This is because cyclohexane plant 1 undergoes recycle, which used more equipment than cyclohexane plant 2.
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Table 3: Comparison of Economic Metrics for two Cyclohexane Plant Economic Parameters
Cyclohexane Plant 1
Cyclohexane Plant 2
Revenue
$16.1
$15.7
Operating Cost
$6.97
$1.24
Waste Treatment Costs
$0.59
$1.1
Raw Material Costs
$93.6
$93.4
Capital Costs
$5.1
$3.7
Annualized Capital Cost
$0.6
$0.4
Material Value Added
$67.9
$63.3
Profit
$59.7
$60.5
As shown in Fig. 4, there was a specific environmental impact that did not involve in this cyclohexane production. This is due to both cyclohexane plants do not have a chemical that leads to atmospheric acidification, aquatic acidification, aquatic oxygen demand, and ecotoxicity to aquatic life at the waste streams. The only environmental impact related to the process were global warming, stratospheric ozone depletion, photochemical smog depletion, and eutrophication. From the bar chart in Fig. 4, can see that cyclohexane plant 2 has the higher potential to cause global warming to the environment than cyclohexane plant 1.
Fig. 4: Results of Environmental Impacts from the Sustainability Evaluator from two Cyclohexane Plants
Social impacts were also evaluated for both processes in the sustainability evaluator. Social impacts can be categorized into 2 categories, which are a safety risk and health impact. The results of the health impact were shown in Fig. 5. The significant health risk that involves both productions of cyclohexane production plants was neurological damage and respiratory damage.
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Health Impact 3.50E+03
Tonnes/year
3.00E+03 2.50E+03 2.00E+03 1.50E+03 1.00E+03 5.00E+02 0.00E+00 Neurological Damage
Respiratory Damage
Cyclohexane Plant 1
Cyclohexane Plant 2
Fig. 5: Results of Health Impacts from Sustainability Evaluator of two Cyclohexane Plants
The safety risks assessments for both processes were compared in Table 4. The results indicate that the total inherent safety index for cyclohexane plant 1 and cyclohexane plant two were 40 and 32, respectively.
Table 4: Results of Safety Metrics from Sustainability Evaluator The output of Process Safety Evaluation Flammability Index
Cyclohexane Plant 1
Cyclohexane Plant 2
8
6
Explosiveness Index
8
8
Toxic exposure Index
4
4
Temperature Index
4
4
Pressure Index
4
4
Equipment safety Index
4
2
Inputs for the safety level of process structure
8
4
Total Inherent safety Index
40
32
3.2.1 The Selection of the More Sustainable Cyclohexane Plants Production
For the overall sustainable impact value, as shown in Table 5, cyclohexane plant 2 has a lower sustainable value, which had 0.12 compared to cyclohexane plant 1, which had a value of 0.16. Based on the result and overall sustainability impact that obtained from the sustainability evaluator, it can be concluded that cyclohexane plant 2 has the more suitable products in terms of economical, environmentally friendly and socially acceptable compared to the cyclohexane plant 1.
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Table 5: Overall Sustainability Impact from the Sustainability Evaluator for two Cyclohexane Plants
Economic Impact
4.
Cyclohexane Plant 1
Cyclohexane Plant 2
0.00
0.00
Environmental Impact
0.14
0.14
Social Impact
0.28
0.15
Sustainable Impact
0.16
0.12
Conclusion
As a conclusion, the purpose of this research project is to design a cyclohexane plant using Aspen HYSYS. It helps to save time and energy for designing a plant. Besides, it helps to find the suitable thermodynamics properties of production. This was proved that the thermodynamics fluid package that suitable to use in the production of cyclohexane in this simulation was Soave-Redlich Kwong model (SRK). Next objective was to perform the comparison between two different roots of cyclohexane plants and to evaluate both plants using sustainable evaluator. Sustainability evaluator act as a calculator that consists of economic, environmental, and social impacts. From the simulations, it can be concluded that cyclohexane plant 1 gave the highest production of the yield of 95% compared to cyclohexane plant 2 of 92.1%. The purity for both of the cyclohexane plants was 99% in the liquid phase. From the sustainability evaluator, it can be used to find the best sustainable chemical plants in terms of economic, environmental, and social impact. Based on the result that has attempted in the sustainability evaluator, the overall sustainability impact index number can be obtained from the sustainability calculator. The results for the sustainability evaluator of cyclohexane plant 1 and cyclohexane plant 2 were 0.16 and 0.12, respectively. It can be concluded that cyclohexane plant 2 has more sustainable production in terms of economical, environmentally friendly, and socially acceptable compared to the cyclohexane plant 1. Acknowledgments We would like to acknowledge and thank to everyone who had contributed to the successful completion of this project especially to Malaysian Institute of Chemical & Bioengineering Technology (UniKL MICET) to provide the software to be used during the project and Majlis Amanah Rakyat (MARA) for the financial assistance. References [1] Cyclohexane Molecule (2016). Available at: https://www.worldofmolecules.com/solvents/cyclohexane.htm (Accessed: 13 March 2018). [2] Cyclohexane Market Size & Share | Global Industry Report, 2014-2025 (2016) Aug 2017. Available at https://www.grandviewresearch.com/industry-analysis/cyclohexane-market (Accessed: 19 February 2018). [3] Claudemir Ribeiro (2018) 1270 Aspen HYSYS Product Brochure FINAL - Tutorial - Hysys. Available at: http://www.ebah.com.br/content/ABAAAeqFEAK/1270-aspen-hysys-product-brochure-final (Accessed: 13 March 2018). [4] Maureen Hart (2010) Introduction to Sustainable Development | Sustainable Measures, Sustainable Measures. Available at: http://www.sustainablemeasures.com/node/42 (Accessed: 11 September 2018).
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