Combustion characteristics, performances and emissions of a biodiesel-producer gas dual fuel engine with varied combustor geometry

Accepted Manuscript Combustion characteristics, performances and emissions of a biodiesel-producer gas dual fuel engine with varied combustor geometry

Swarup Kumar Nayak, Purna Chandra Mishra PII:

S0360-5442(18)32327-2

DOI:

10.1016/j.energy.2018.11.116

Reference:

EGY 14214

To appear in:

Energy

Received Date:

20 July 2018

Accepted Date:

25 November 2018

Please cite this article as: Swarup Kumar Nayak, Purna Chandra Mishra, Combustion characteristics, performances and emissions of a biodiesel-producer gas dual fuel engine with varied combustor geometry, Energy (2018), doi: 10.1016/j.energy.2018.11.116

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ACCEPTED MANUSCRIPT Combustion characteristics, performances and emissions of a biodieselproducer gas dual fuel engine with varied combustor geometry Swarup Kumar Nayak1, Purna Chandra Mishra1,* School of Mechanical Engineering, KIIT (Deemed to be University), Bhubaneswar, Odisha *[email protected] Mob: +91-8280327066 Abstract This paper presents the overall performance, emission and combustion characteristics of the engine, when fuelled with biodiesel blends of Calophyllum Inophyllum methyl ester as injected fuel and babul wood chip derived producer gas as inducted fuel at constant injection timing (230bTDC), injection pressure (230 bar) and speed (1500 rpm). To improve overall performance, combustion and reduced emission characteristics of the engine, the combustion chamber was varied with 5 different geometries. Experimental results revealed that Toroidal re-entrant combustion chamber had higher Exhaust Gas Temperature and Brake Thermal Efficiency by 20.75% and 6.37% than that of HCC, while Brake Specific Fuel Consumption was reduced by 4.49% at optimal loading condition. However, engine overall performance of TrCC was found to be comparable with Hemi-spherical chamber and other designed combustion chambers. Similarly, comparing exhaust emissions, Oxide of Nitrogen and Carbon dioxide were on its higher side by 19.90% and 27.20% than normal HCC. On the contrary, carbon monoxide, Hydrocarbon and Smoke opacity for TrCC were found to be 76.12%, 33.71% and 38.67% lower than HCC. From the above study, it is finally concluded that converted renewable fuels with TrCC might be utilized as an alternative fuel without any exhaust related problems. Keywords:

Renewable fuel, waste babul wood chip; combustion chamber geometry;

Emission; cylinder pressure; heat release rate.

ACCEPTED MANUSCRIPT Nomenclature bTDC

before Top dead centre

SrCC

Shallow depth re-entrant combustion chamber

RPM

Rotation per minute

BTE

Brake thermal efficiency

CIME

Calophyllum inophyllum

BSFC

Brake Specific Fuel

methyl ester SCC

Shallow depth combustion

Consumption EGT

Exhaust Gas Temperature

CO

Carbon monoxide

CO2

Carbon dioxide

NOx

Oxide of Nitrogen

chamber HCC

Hemi-spherical combustion chamber

TCC

Toroidal combustion chamber

TrCC

Toroidal re-entrant combustion chamber

CP

Cylinder pressure

CNG

Compressed natural gas

ID

Ignition delay

LPG

Liquid petroleum gas

HC

Hydrocarbon

TDI

Turbo-charged diesel engine

HRR

Heat release rate

KOH

Potassium hydroxide

EIA

Energy Information

ASTM

American Society for

Administration

testing and materials

1. Introduction 1.1. General background:Energy is most essential part for the economic growth of any nation. It enhances economic property personal comfort and quality of life there is more demand of fuel. Conventional fuel plays a very important role in the field of industrial developments, transportation and agriculture sector because of its accessibility. Ignition properties and higher calorific values [1,2].The International Energy Agency, estimated that by the end of 2030, the net energy consumption will increase by more than 55% [3-5]. The Energy Information Administration

ACCEPTED MANUSCRIPT (EIA) of the United States predicted that net petroleum products utilization and consumption will increase from around 86 million barrels per day to 110 million barrels per day by the end of 2035 [6, 7]. Due to the rapid depletion in conventional fuels, the rising price of petroleum products and major current environmental issues have gathered momentum in finding out a substitute, an alternative source of energy, which can replace the current conventional fuel in the future. Hence, it has become a worldwide challenge to develop a clean, renewable, environmental friendly, easily available and technically feasible advanced fuel. Biodiesel is categorized as alternative fuel or advanced fuel, which has the capability to meet the current energy demands all around the globe, thereby reducing global warming [3, 8-11]. According to the literature, renewable energy will become the second largest source of power generation by the end of 2020, and by 2035 it will approach coal as the main source of electricity [12, 13]. In developing countries such as India and in many other developing countries, biodiesel will play a major role in diminishing the dependence on fossil fuel, the rising price of the products and various effects of global warming, which imparts an adverse effect upon human health [14-17]. Biodiesel is directly produced form straight vegetable oils (SVO'S) such as Karanja, Mahua, Neem, Polanga,CalophyllumInophyllum, Jojoba, Simarouba etc., which are often referred to as non-edible oils or animal fats, tallow and waste cooking oil by the esterification and transesterification process. The transesterification process is the reaction of a triglyceride oil with an alcohol i.e. methanol or ethanol to form methyl or ethyl esters and glycerol as by products [9, 18]. Biodiesel is considered to be safer than diesel because of its higher flash point and fire point. It constitutes a good percentage of oxygen which on burning emits less carbon monoxide (CO) and hydrocarbon (HC), but at the same time it enhances the nitrogen oxide (NOx) emission, which is the most harmful parameter that may lead to acid rain and smog thereby causing environmental degradation. Keeping in view of present energy crisis, dependence on imported fossil fuels, global

ACCEPTED MANUSCRIPT warming and effect of human health due to hazardous emission emitted by petroleum driven vehicles , global interested is generated to do more research work to find more suitable alternative fuel for modern diesel engines. The gaseous fuels are getting more positive response from various other researchers because gaseous fuels are clear burning fuel which generates less CO2 and NOx the two main culprits of greenhouse gas effect and acid rain[19, 20]. Various gaseous fuels like CNG, LPG, Hydrogen, Biogas, Syngas and producer gas have been effectively utilized for partial or complete substitution of diesel fuel for modern diesel engines. Biofuel, for example, biodiesel and maker gas got from biomass are being considered as better elective fuel keeping in mind the end goal to guarantee both nourishment and vitality security in the predominant circumstance of shortage of non-renewable energy sources [21-24]. Use of vaporous fuel alongside biodiesel infused fuel if there should be an occurrence of a turbo charged diesel engine prompts ignition with greater much better quality since it includes two different fuels with non-comparative properties which is burnt combined inside engine cylinder due to which the heat release rate is reduced because of three combustion stages [25-27]. Dual fuel operated diesel engines are well known for the percentage of diesel fuel savings with reduces NOx and CO2 level, the main culprits of acid rain and greenhouse gas effects. Many researchers stated reduced engine performance, decrement in NOx and CO2 but slight increment of HC and CO under dual fuel operating modes [22, 28-35].The significant issue related with producer gas energized dual fuel mode diesel engine is their capacity derating . A percentage of diesel savings upto 70-85% has been reported for dual fuelling [21, 24-25, 36-42]. A perfect and good chamber provides best squish of air, in this manner driving air to the centre point of chamber, which results in turbulence [26]. Presently, the modern engines utilize hemi-spherical combustion chamber (HCC) which depicts good performance and emission for diesel. Nevertheless, it might not be good enough for the currently fuelled biodiesel and producer gas as inducted and injected

ACCEPTED MANUSCRIPT fuel. Therefore, the researchers suggested design of various combustion chambers for presently utilized alternative fuels [43-46]. Numerous Literature works have detailed with reference to fuel properties and its effect on dual fuel mode. In any case, not literature works have been accounted for on fundamental engine modification. Along these lines, usage of producer gas in exhibit current engine requires all the more profound examination. Improvement in engine general execution with diminished emission of producer gas fuelled dual fuel engine needs more investigation concerning both the properties of fuel and engine outline and modifications. Thus, an exertion has been made to shorten negative impacts and it is presently very important to research the impacts of varying chamber geometry on overall performance and combustion analysis of a turbo charged diesel engine worked in dual fuel mode. 1.2. Present research work Impact of varying chamber geometry on the execution of single fuel activity has been accounted for in the literatures. The literature reviews propose that impact of varying combustion chamber geometry on general execution of biodiesel-producer gas fuelled double fuel turbo-charged engine has been least examined. In current situation, this field of research needs detail examination and consideration up on upgrade of producer gas thermal efficiency worked on TDI engine in dual mode, with reduced emissions. Presently, the investigation is carried out on a turbo-charged DI diesel engine operated in dual fuel mode using Calophyllum Inophyllum oil methyl ester and babul wood chip generated producer gas, by varying different types of combustion chambers like SCC, TCC, SrCC, TrCC and HCC were optimized to deliver better engine performance and emission. Finally, the results were compared with that of baseline data of conventional diesel fuel and analysed suitably.

ACCEPTED MANUSCRIPT 2. Material and Method 2.1. Source of calophyllum Incophyllum oil Calophyllum Inophyllum is a medium sized tree up to 12m in height having an erect cylindrical growth as visualised in Figure 1. The leaves are deep green, leathery and 15 cm long. This tree belongs to Garcinia (Clusiaceae) family which grows with under moist tropical climate. On the west coast, it is found from Mumbai southward toward southern Kerala and along east coast of Odisha [47]. It can grow in wide variety of soils ranging from muddy clay to coastal sands, as well as in non-cultivable land with an annual rainfall of 700 5000 mm. The average oil yield is 11.8 kg/ton or about 4600 kg oil/hectare [47]. The high oil content, easy availability, growth on barren lands and low water requirements are the properties which make this oil best suited for the current investigation. The free fatty acid composition of Calophyllum Inophyllum oil is described in Table 1. 2.2. Source of Babul wood chips Woody biomass is well known fuel in developing nation like India and now it is traditionally used for generation of heat because of its higher heating value, high octane number and lower ash content [30]. Babul wood, commonly known as babul (Acacia nilotica) is widely available in Odisha as well as in various states of northern India [47]. Babul is a medium sized tree that grows to a height of 24 m. The wood chips generally have high calorific value and density with minimal moisture content of 18% in comparison to other wood chips available in India [48]. For the current investigation, Babul wood chips of dimension 20 x 20 mm in length and diameter was prepared within the premises and feed up to the gasifier as per the suitability. Figure 2 depicts the shape and size of the babul wood pieces.

ACCEPTED MANUSCRIPT 1.1. Conversion of Calophyllum Inophyllum oil to Biodiesel Initially the non-edible oil is pre-heated to a temperature of 1000C-1100C in order to increase its volatility and then filtered with the help of a nylon mesh cloth. After filtration, the raw oil undergoes degumming process where, 1% (ortho-phosphoric acid) is used for removal of gum deposit from the raw oil. Now the degummed oil under goes esterification process where the oil is mixed with 20% of methanol and 0.8-1% of sulphuric acid (H2SO4) inside a selffabricated biodiesel reactor for 2-3 hours maintaining a constant temperature of below 600C with the help of a heating mantle . The oil is then allowed to settle down inside the reactor for about 8-10 hour for obtained acid treated biodiesel. The treated oil is now applied for transesterification process where 22% of methanol is mixed with 0.6-0.8% of base catalyst KOH is added. The mixture then stirred continuously at fixed RPM below 60% that is boiling point temperature of methanol for 2-3 hours. The stirring is stopped and mixture was allowed to settle inside the reactor for 8 hours. The biodiesel obtained is further washed with the help of distilled water using 2-3 drops of ortho-phosporic acid for removing excess esters and base KOH. Finally the oil is heated above 700C to remove additionally methanol to obtained pure biodiesel. Figure 3 shows the various treatment processes for biodiesel preparation. In the present study, biodiesel is blended with diesel in various volume proportions i.e., CIME 20 where CIME 20 represents 20% biodiesel & 80% diesel. The prepared test fuel blends undergo various physio-chemical tests in order to determine its feasibility of usage as alternative fuel for present diesel engine. Table 2 depicts the percentage of error all measuring instruments that were used to measure different fuel properties as per ASTM D6751 standard.

ACCEPTED MANUSCRIPT 1.2. Physio-Chemical Properties of Biodiesel 1.2.1. Specific Gravity It is also termed as Density of the fuel to that of the density of water at same temperature. The density of the fuel was measured utilizing density bath with hydrometer at 25 0C for all the prepared test fuels using ASTM D1298. Relative value for CIME 20 was obtained at 0.788% higher than that of conventional diesel fuel which leads to higher flow resistance of fuel, resulting in higher viscosity thereby causing inferior injection of fuel [49]. The density values obtained for the entire prepared test fuel blends lie within the range of 0.85-0.9 g/cm3 as per the ASTM D6751 standard. The details of density chart for all the test fuel blends were depicted in Table 3. 1.2.2. Flash Point and Fire Point Flash point term indicates the minimum temperature at which the vapour from the procured fuel will flash a blink of flame above the fuel surface when heated to a requisite temperature without catching fire [49, 51]. Flash point plays an important role in determining the hazardous nature of any test fuel. Table 3 denotes that CIME 20 has 108.47% and 102.94% higher flash point and fire point than natural diesel fuel. As per ASTM D93 the values depicted in the table for all the prepared test fuel blends lie within the acceptable limits. Fire point is known as the minimum temperature at which the vapour over the fuel surface will continue to burn once ignited. Both flash and fire point were measured using Pensky Marten flash and fire point apparatus. From Table 3 it is conclude that CIME biodiesel blends have higher flash and fire point temperature than normal diesel which makes it safer for storage and transportation. 1.2.3. Cloud Point and Pour Point Cloud point and pour point are used for detecting the cold point temperature usability of any fluid [49-51]. Cloud point is the minimum temperature at which a wax crystal cloud will

ACCEPTED MANUSCRIPT appear in an oil when it is cooled to a particular temperature. The cloud point for CIME 20 were observed to be 40% higher, while pour point was observed to be same as that of diesel because of higher density and viscosity of the biodiesel, but the values lie within the acceptable range per the ASTM D2500 and ASTM D97 standards. Both cloud and pour point were measured using Seta cloud and pour point bath apparatus. 1.2.4. Kinematic Viscosity Kinematic viscosity is defined as the degree of fluid flow to resistance. High viscosity lead to engine deposit as it hampers the fuel atomization during combustion inside the engine cylinder [49]. The parametric test for kinematic viscosity was carried out using Saybolt Kinematic Viscometer at a temperature of 400C for all the prepared test fuel blends. Table 3 depicts CIME 20 establish nearby result of 2.02% higher to that of diesel fuel, but the values lie within the acceptable range per the ASTM D445 standards. 1.2.5. Calorific Value Calorific value determines the amount of heat generated inside the combustion chamber during combustion and it also specifies the net energy available in the test fuel [49, 52, 53]. Parametric test for the calorific value is carried out using Bomb Calorimeter for all prepared test fuels using ASTM D 4809. From the Table 3 it can be seen that CIME 20 yield calorific value quiet comparable to that of conventional diesel fuel. CIME 20 depicts calorific value 3.30% lower than diesel because of high density and viscosity. 1.2.6. Acid value Acid value determines the amount of carboxylic acid presence, like in free fatty acids. Acid value was the number of milligrams of potassium hydroxide required to neutralize the free fatty acid present in 1gm of oil. Biodiesel with higher acid value may cause severe damage to the engine, thereby causing fuel system corrosion [54, 55]. Parametric test for the acid value is carried out using colour indicator titration for all prepared test fuels using ASTM D974 i.e.

ACCEPTED MANUSCRIPT set to a maximum limit of 0.5 KOH/gm in ASTM (D 6751) [36, 54]. From the Table 3 it can be seen that CIME 20 yield acid value quiet comparable to that of conventional diesel fuel. CIME 20 depicts acid value 17.27% lower than diesel because of high density and viscosity [49]. In the titration process, N/10 KOH, neutral ethyl alcohol and phenolphthalein indicator were required in this experiment. 1.4 gm of KOH was dissolved in 250 ml of distilled water to make a solution. 0.5-1 gm of non-edible oil sample was added to 20-22 ml ethyl alcohol and stirred well for 2-4 minutes. 3-4 drops of phenolphthalein indicator was then added into the resulting solution. The resulting solution was titrated with KOH in order to calculate the acid value of the non-edible oil. Acid value was the number of milligrams of potassium hydroxide required to neutralize the free fatty acid present in 1.0 gm of oil as per equation 1. The Table 3 is modified as required in the revised list Tables. Acid value=

{𝑉𝑜𝑙𝑢𝑚𝑒 𝐾𝑂𝐻 (𝑚𝑙) ∗

(

𝑁 𝑚𝑚𝑜𝑙 𝐾𝑂𝐻 𝑚𝑙 10

𝑚𝑔 ) ∗ 56.1 (𝑚𝑚𝑜𝑙 )}

𝑆𝑎𝑚𝑝𝑙𝑒 𝑤𝑒𝑖𝑔ℎ𝑡 (𝑔𝑚)

_____________________________ (1)

1.2.7. Methanol content In the present work, the methanol content was recorded as per the method described by Romano et al., 2009 [56]. The measurements show that there is a strong correlation between flash point and methanol content. Equation (2) fits very well the experimental data, with a correlation coefficient (R2) greater than 0.99: y = 38 x^-0.6______________________________________________________________ (2) where x is the methanol content in biodiesel (% V/V) and y is the flash point of the sample (°C), with x ≥ 0.2. Flash point of CIME 20 sample with no methanol added always exceeded the maximum flash point value that could be measured with the equipment (> 180°C). It is important to remark that the measured flash point value at the maximum methanol content set by international standards (0.2%) corresponds to the minimum allowable flash point (130°C min.) according to the standards as depicted in Figure 4 and the concern methanol content data is incorporated in Table 3 of revised list of Tables.

ACCEPTED MANUSCRIPT 1.1. Conversion of babul wood chip to producer gas Gasification is a thermo-chemical conversion process of waste solid biomass into gaseous fuel by pyrolysis inside a gasifier pertaining at high temperature. The producer gas was generated from waste babul wood chips inside a down draft gasifier setup. The down draft biomass gasifier consist of a big reactor, gas cooling unit, two set of gas filters (active and passive) and a gas surge tank for storage of the gaseous fuel. The detailed specification of the down draft gasifier is depicted in Table 4. The photographic sketch of the downdraft biomass gasifier is visualised in Figure 5. The loading of the biomass feedstock occurs from the top of the gasifier, while ash removal occurs manually from the bottom part of the down draft gasifier at regular interval of time. The feedstock then make up its way inside the gasifier through 4 distinctive processes to generate producer gas i.e. drying of the fuel in drying zone, pyrolysis process where tar and other volatile particles are driven off, combustion zone and reduction zone. The partially generated hot producer gas having temperature of around 5100C enters into the gas cooling unit, thereby reducing the temperature to 380C. The cooled gas contains moisture for and dust particles which were removed by passing through both passive and fine filters. Then after, the cooled and filtered gas is made to through an orifice meter into the intake manifold. The different physio-chemical properties of Babul wood chips under both wet basis and dry basis are depicted in Table 5. 1.2. Development of Combustion chambers for dual fuel operation Blend arrangement inside the motor barrel primarily relies on the combustion chamber shape and configuration. In case of current study, in order to investigate the performance, outflow and ignition attributes of a turbo charged twin cylinder diesel engine fuelled with biodiesel as injected fuel and producer gas as inducted fuel by varying the combustion chamber geometry to have TCC, SCC, SrCC & TrCC from the baseline of HCC. Figure 6 depicts the layout sketch of different combustion chambers geometries. The bowl volume was maintained

ACCEPTED MANUSCRIPT constant. This is due to the fact that by keeping bowl volume constant, the compression ratio will be maintained same for all combustion chambers. The other dimensions are tabulated in Table 6 for all varieties of combustion chambers and Figure 7 shows the actual image of all the modified combustion chambers. In shadow depth combustion chamber, the depth of the cavity provided in the piston is small. Although the cavity diameter is large, it provides small squish and swirl motion. Hemispherical combustion chamber also provides small squish and swirl motion. Toroidal combustion chamber furnishes a ground-breaking squish alongside twirl movement of the air empowers quick vanishing of exceedingly atomized fuel in this manner empowering complete burning. Re-entrant combustion chamber, the lip of the chamber protrudes beyond the boundary wall of the bowl which gives a considerable change in execution and emanation over burning chambers. In case of Re-entrant combustion chamber the fuel is first directed down towards the bowl and then towards the centre of the bowl. 1.3. Experimental setup:1.3.1. Engine Test Rig:The experiment was carried out on a turbo charged the twin cylinder direct injection diesel engine. The engine test rig figure and complete specification are depicted in Figure 8 and Table 7. An eddy current dynamo was utilized for varying load condition thereby maintaining speed constant at 1500 rpm. The flow rate of the producer gas was maintained constant. For dual operating condition, various engine parameters like fuel injection timing, injector opening pressure, compression ratio were maintained constant at 230bTDC, 230 bar and 17.5 respectively. In the present study, a down draft gasifier were utilized for generation of producer gas. This is due to fact that down draft gasifier emits fewer amounts of HC and particulates in comparison to other gasifier as per literature survey [53]. For operating the engine in dual fuel mode, initially the down craft gasifier has to be coupled to the engine. The

ACCEPTED MANUSCRIPT feedstock is loaded from the top and flow of air is through combustion and reduction zone from the bottom of the gasifier. The combustion of biomass feedstock inside the gasifier unit is converted into high temperature producer gas, followed by enforce into gas cooling unit. The cooled gas contains moisture for and dust particles which were removed by passing through both passive and fine filters. Then after, the cooled and filtered gas is made to through an orifice meter into the intake manifold. Nira soft is the software used for the communication of the data between the engine test rig and data acquisition system through a control panel. The current software explores the brake thermal efficiency, specific fuel consumption, heat release rate, ignition delay and pressure crank angle diagram. A piezoelectric pressure transducer was mounted onto the cylinder head to measure the cylinder pressure. The emission characteristic were observed under varying load condition for all prepared test fuels and were measured with the help of a 5-gas analyser (AVL-444) and smoke meter (AVL-437) in order to determine smoke emission. The complete specification of smoke meter and exhaust gas analyser are depicted in Table 8 and Table 9 respectively. All the measurements were carried out when the engine attend steady state condition. For each loading conditions, the required experiments were repeated for five times for the prepared test fuel blends in order to determine the repeatability and reproducibility of the collected data, average value and accuracy of each parameter. 1.3.2. Uncertainty Analysis The uncertainties of the measured parameter are estimated and reduced to certain extent by thorough selection calibration of the measuring instrument. Thereby, planning the experiments repeated for three times. In a systematic manner the experiment errors are obtained for engine performance like BTE, BSEC & EGT. Similarly exhaust gas emersion like CO, CO2, HC, NOx and smoke capacity. Uncertainties of the described parameter are

ACCEPTED MANUSCRIPT show in Table 10. The uncertainty data revels that the two valves of the parameter lies within the acceptable range. 2. Result and Discussion 2.1. Engine Performance Parameters 2.1.1. Brake Thermal Efficiency (BTE) Figure 9 shows the variation of BTE with respect to different combustion chambers configuration. With different combustion chambers BTE for diesel was varying over the entire load range. There was a continuous increment in BTE for all test fuels for all combustion chambers up to optimal loading condition due to higher charge temperature resulting in desirable combustion efficiency. However at full load, BTE declined due to lower combustion as a result of insufficient oxygen content [57]. The brief research with different combustion chambers shows that CIME 20-producer gas with TrCC resulted in better completion in comparison to rest of the other. This might be because of the way that TrCC prevent the fire from spreading over to the squish zone bringing about more attractive blend preparation of CIME 20 and producer gas [57, 58]. It is additionally discovered that TrCC can possibly coordinate the flow field inside the sub-volume at all loads and in this manner generous contrasts in blending propagation may likewise be in charge of this sort of pattern. Usage of ordinary HCC may cause an addition in ignition delay amid the ignition of CIME 20-Producer gas blend that show case a diminishment in BTE. Consequently, the utilization of TrCC for the ignition of CIME 20-Producer gas brings about enhanced burning amid power stroke. Therefore, keeping the dissemination of flame in the squish area, providing an improved performance. It can be seen that with lessening in pilot fuel infusion may cause decrease in the ignition source in this way prompting partial ignition at lower loads. It is additionally pictured that lower gas flow rate won't influence the combustion [55]. In any case, higher gas flow rate influences the air-comparability proportion essentially. Hence, it

ACCEPTED MANUSCRIPT lowers the overall performance of the engine. The BTE for SCC, TCC, TrCC and SrCC were measure to be 17.12%, 6.04% lower while, 6.37% and 2.05% higher and 13.12%, 4.92% lower and 5.78% and 1.34% higher than that of HCC for optimal loading condition and full loading condition at 28.27% and 31.27%. 2.1.2. Brake Specific Fuel Consumption (BSFC) The variety of BSFC as for various load conditions with differing combustion chamber geometries are portrayed in Figure 10. It is watched that with increment in load, BSFC for all test energizes with combustion chambers demonstrates a declining bend because of better ignition due to higher charge temperature of increment in load [57]. Nonetheless, at most elevated loading condition, BSFC for all fuels with combustion chambers, increases as a result of inadequate oxygen content causing partial burning in the engine cylinder. Among all the combustion chambers, it was seen that TrCC displayed better BSFC in comparison to that of other types. This may be due to improved swirl velocity and air-fuel mixture preparation [57, 58]. Another reason may be lower calorific value and higher density of CIME. The BSFC for SCC, TCC, TrCC and SrCC were measure to be 22.14%, 9.14% higher and 4.49%, 1.38% lower and 16.21%, 8.11% higher and 3.86% and 4.63% than that of HCC for optimal loading condition and full loading condition at 28.27 Kg /kW-hr and 31.27 Kg /kW-hr. 2.1.3. Exhaust Gas Temperature (EGT) The Figure 11 describes about the variation of EGT with respect to load (kW) for different combustion chambers in dual fuel mode of operation for all test fuels. The EGT in double fuel mode activity for all test fuels is higher than their single mode at all operating conditions. This may be because of higher vitality discharged after the burning stage because of higher delay period of moderate ignition producer gas [57]. Once more, with increment in load, EGT for all combustion chambers increments because of the higher vitality contribution to the

ACCEPTED MANUSCRIPT engine cylinder bringing about a higher EGT [58]. Among all the chambers, it was seen that TrCC chamber showed higher EGT in contrast with that of other combustion chambers. This might be because of complete combustion owing to improved air-fuel blending and presence of oxygen concentration in CIME mixes [57, 59]. The EGT for SCC, TCC, TrCC and SrCC were measure to be 1.01%, 15.44%, 20.75%, 17.21% and 3.30%, 11.89%, 20.92%, 17.62% higher than that of HCC for optimal loading condition and full loading condition at 3950C and 4540C. 2.2. Engine Emission Parameters 2.2.1. Smoke opacity The variations of smoke opacity with respect to load (kW) for different combustion chambers are depicted in Figure 12. Smoke opacity for diesel-producer gas was bringing down in contrast with that of CIME-producer gas. This may be because of despicable blending rates and lessened oxidation amid ignition. Notwithstanding, the lower air-fuel blend comparability proportion got for CIME 20-Producer gas activity might be the purpose behind such pattern [57]. Among all considered combustion chambers, TrCC for CIME 20-Producer gas task guarantees bring down smoke value than other combustion chambers at same working parameters. The reason might be because of the way that enhanced air-fuel blending and better air use as a result of the ideal turbulence inside combustion chamber [57, 58]. This aspect comes about better burning and oxidation of the soot particles which additionally lessens the smoke opacity levels. The smoke opacity for SCC, TCC, TrCC and SrCC were measure to be 16.67%, 29.28%, 38.67%, 33.33% and 8.33%, 20.12%, 29.41%, 22.61% lower than thatof HCC for optimal loading condition and full loading condition at 61.8% and 72.11%.

ACCEPTED MANUSCRIPT 2.2.2. Hydrocarbon (HC) and Carbon monoxide (CO) Figure 13 and Figure 14 delineates the variety of UBHC and CO outflow with respect to load (kW) for special types of combustion chambers. For similar combustion chambers, dieselproducer gas operation portrays lower HC and CO in contrast to CIME 20-Producer gas as a result of diesel-producer gas attributes proper blending of both air-fuel and improved oxidation amid ignition [58]. Another reason may be due to complete burning of dieselproducer gas on account of appropriate usage, amid ignition. If there should arise an occurrence of double fuel method of operation, inadequate burning is predominantly because of substitution of air by biomass generated producer gas.From the above both the figures it was also observed that HC and CO emission was less for TrCC chamber in comparison to all other combustion chambers. This may be because of the way that, there is a superior burning of CIME 20-producer gas in TrCC because of enhanced swirl and squish movement of air amid double fuel operation. Be that as it may, commonly used combustion chamber may not add to appropriate blending of fuel burning prompting partial combustion during double fuel operation. It might be because of restriction in the second rate some portion of the bowl by the vortex produced with HCC arrangement [58, 59]. The HC for SCC, TCC, TrCC and SrCC were measure to be 10.91%, 23.75%, 33.71%, 18.54% and 11.16%, 11.16%, 30.18%, 16.49% lower/higher than that of HCC for optimal loading condition at 54.13ppm and 65.95ppm. Similarly, The CO for SCC, TCC, TrCC and SrCC were measure to be 38.46%, 46.15%, 76.12%, 53.84% and 25.26%, 25.26%, 53.15%, 37.89% lower than that of HCC for full loading condition at 0.039% and 0.190%. 2.2.3. Oxide of nitrogen (NOx) The variation of oxide of nitrogen with load (kW) for different combustion chamber geometry is depicted in Figure 15. From the above figure it can be observed that for same

ACCEPTED MANUSCRIPT configuration of Combustion chamber, NOx emission was higher for diesel-producer gas than that of CIME 20-producer gas operation for all loading conditions. This may be due to excess heat release rate amid pre-mixed combustion stage that happens with mixture of both diesel and producer gas [57, 58]. Moreover, during ignition of CIME 20-producer gas mixture, the concentration of oxygen content was too low and this may be another reason for such kind of curve. CIME 20- producer gas operation, delivers marginally higher NOx for TrCC in comparison to that of HCC. This might be due to slight better combustion in view of homogeneous blending and enhanced air usage attributable to improved swirl and squish motion [59]. Majority of agitation happened in advance of top dead centre. This is because of lower ignition delay. The Nitric oxide emission for SCC, TCC, TrCC and SrCC were measure to be 13.13%, 20.04%, 26.72%, 22.35% and 8.17%, 17.88%, 19.90%, 16.04% higher than that of HCC for optimal loading condition and full loading condition at 434 ppm and 648 ppm 2.2.4. Carbon dioxide (CO2) Figure 16 depicts the variation of CO2 with respect to load for various types of combustion chamber geometry. Considering similar combustion chambers during experimentation, it is seen that CO2 emission was more for CIME 20-Producer gas for all loading conditions. This might be due to excess heat release rate during pre-mixed phase of combustion. Secondarily, in case of engine operated in dual fuel mode, the oxygen content reduces and this leads to higher CO2 emission [57-59]. Moreover, considering TrCC chamber, CO2 emission was more for CIME-producer gas than natural aspirated mode, due to improved combustion because of homogeneous mixing and improved air utilization caused by better squish as well as swirl motion with TrCC [58]. The carbon dioxide emission for SCC, TCC, TrCC and SrCC were measure to be 5.10%, 32.76%, 47.44%, 36.38% and 2.32%, 14.08%, 27.70%, 19.81% higher

ACCEPTED MANUSCRIPT than that of HCC for optimal loading condition and full loading condition at 4.70% and 6.46%. 2.2.5. Diesel fuel savings The slope of diesel fuel savings verses load for various fuels with different combustion chamber geometries are depicted in Figure 17. For same operating parameters, pilot fuel savings for diesel-producer gas combination was more than that of CIME-producer gas operation, for TrCC chamber in comparison to that of all other types. This may be due to better squish and swirl motion of air causing complete combustion of both injected fuel and inducted producer gas. The amount of fuel replacement was found to be lower at initial loading condition. Similarly, it can also be seen that producer gas fuel replacement was at its higher end in case of optimal and full loading condition due to control of liquid fuel supply [58]. The pilot fuel savings for SCC, TCC, TrCC and SrCC were measure to be 18.50%, 11.71%, 3.01%, 4.96% and 15.53%, 14.48%, 1.92%, 7.26% lower than that of HCC for optimal loading condition and full loading condition at 80.5% and 76.103%. 2.3. Engine Combustion Parameters 2.3.1. Ignition delay (ID) Ignition delay is the time from the start of fuel injection to the start of fuel combustion. Figure 18 depicts the variation of ID with respect to load (kW) for all combustion chamber geometries. It was observed that the ignition delay period of CIME 20-Producer gas was significantly higher than that of diesel-producer gas for different combustion chambers. This may be due to the variation in the air-producer gas mixture, the lower calorific value of both CIME 20 and producer gas, lower flame temperature of producer gas and higher viscosity of CIME [59]. Hence, it requires more time for burning. It was also visualised that among all the combustion chambers, TrCC for CIME 20-producer gas combination depicts lower ignition delay at all loads, which may be due to increased combustion chamber wall temperature and

ACCEPTED MANUSCRIPT reduced exhaust gas dilution at optimal and full loading condition [58]. The ignition delay for SCC, TCC, TrCC and SrCC were measure to be 11.18%, 19.54%, 24.45%, 21.18% and 15.58%, 22.26%, 32.23%, 25.34% lower than that of HCC for optimal loading condition and full loading condition at 110CA and 90CA. 2.3.2. Heat release rate (HRR) Figure 19 shows heat release rate versus crank angle for different combustion chamber geometries. From the graph it can be observed that HRR for CIME-Producer gas operation were lower than that of diesel-producer gas combination. This may be due to shorter ignition delay for CIME-Producer gas. Similarly, poor spray atomization characteristics of CIME due to higher kinematic viscosity, lower calorific value of producer gas and higher surface tension of CIME may be another possible cause of the above trend [58, 60]. Moreover, it can be seen that HRR for CIME-producer gas combination with TrCC chamber depict slightly better curve in comparison to that of other combustion chambers. This might be attributed to the fact that due to improved air-fuel mixing as a result of enhanced swirl and squish motion of air that leads to better combustion [60]. 2.3.3. Cylinder Pressure (CP) Figure 20 shows case the variation of CP versus crank angle for various combustion chamber geometries. The cylinder pressure is higher for the CIME 20-Producer gas combination due to the combined effect of the shorter ignition delay, lower adiabatic flame temperature and slow burning rate of producer gas [60]. The pressure variation of all five combustion chambers followed the similar pattern of pressure rise as that of diesel-producer gas combination with HCC for all loading condition. The cylinder gas pressure trend of TCC with CIME 20-Producer gas was found closer to that of diesel-producer gas with HCC and well above SCC. However, the cylinder pressure of TrCC fuelled CIME 20-Producer gas

ACCEPTED MANUSCRIPT operation was higher than rest all. This can be endorsed to better combustion due to improvement in air entrainment and air-fuel mixing rates together in TrCC [58, 60]. Other reasons for improved performance may be attributed to higher cetane number and higher oxygen content of CIME. Moreover, TrCC fuelled CIME 20-Producer gas combination for the next higher peak was visualised amid diffusion ignition stage for diesel-producer gas with TrCC chamber. The reason for such trend might be because of partial combustion of CIME biodiesel due to its high viscosity as well as poor quality of the producer gas [58]. 3. Conclusion In this experimental phase, the effect of combustion chamber geometry on overall performance of a turbo-charged diesel engine operated in dual fuel mode fuelled with calophyllum inophyllum oil methyl ester and Babul wood chips generated producer gas at standard injection timing of 23 0bTDC and injection pressure of 220 bar respectively. The results were compared with that of normal baseline diesel with producer gas combination in order to select the best combination of combustion chamber shape for overall improved performance of the diesel engine. To evaluate the influence of varying combustion chamber geometry on the overall performance of turbo-charged diesel engine operated in dual fuel mode. Experimental results obtained using the different combustion chambers are depicted below as:1. Among all combustion chamber geometries, TrCC clearly defines higher exhaust gas temperature with respect to load among all tested combustion chambers and for all test fuels because re-entrant combustion chambers lead to more complete combustion as a result of better air-fuel mixing and presence of oxygen in CIME biodiesel blends. 2. In case of BTE, TrCC depicts higher BTE of 6.37% for dual fuel mode in comparison to all other test fuels with varying combustion chambers. This is because TrCC

ACCEPTED MANUSCRIPT prevents the flame front propagation from spreading over to the squish region resulting in better mixture formation of CIME and producer gas. 3. From the experimental study it was also depicted that, TrCC type combustion chamber displayed better BSFC of 4.49% than rest all because of improved swirl velocity and air fuel mixing preparation. 4. Among all the combustion chambers, TrCC for CIME 20-Producer gas combination ensures lower smoke opacity (38.67% lower) than all other test conditions. This may be due to better air-fuel mixing and air utilization caused by optimum turbulence caused by the combustion chamber. 5. HC emission was less for TrCC chamber of 33.71% lower because of better combustion among CIME 20-Producer gas in TrCC as a result of air during dual fuel operation. 6. NOx and CO2 emission is generally higher of (19.90% and 27.70%) for dual fuel engines because of higher HRR during pre-mixed phase of combustion. TrCC emits higher concentration of NOx and CO2 than HCC because there is a slight improvement in combustion due to homogeneous mixing and improved squish and swirl motion of air with TrCC. 7. Pilot fuel savings for diesel-producer gas of about 1.92% higher combination with HCC operation than TrCC used CIME 20-Producer gas combination. This is due to better squish and swirl motion of air that leads to slight belter combustion of high volatile fuel with producer gas. 8. TrCC combustion chamber for CIME 20-Producer gas combination depicts lower ignition delay of 24.45% lower at optimal load condition. The reason may be due to increased combustion chamber wall temperature and reduced exhaust gas dilution at optimal loading condition,

ACCEPTED MANUSCRIPT 9. CIME-Producer gas combination enhanced lower heat release rate due to shorter ignition delay period than that of diesel producer gas operation. Similarly, HRR for CIME-Producer gas operation with TrCC depicts better trends because of improved airfuel mixing as a result of enhanced squish and swirl motion of air that leads to slight belter combustion. 10. The engine developed cylinder pressure for TrCC fuelled CIME-Producer gas combination was higher than other combustion chambers because of better combustion due to improvement in air entrainment and air fuel mixing rate together in TrCC. Hence, the present analysis reveals that overall performance of a turbo-charged diesel engine operated in dual fuel mode can be improved by replacing the existing combustion chamber (HCC) with suitably designed and optimized combustion chambers.Based upon the above results, the engine having TrCC was selected for further studies, to evaluate the effect of different engine variable parameters on overall performance of a turbo-charged diesel engine operated in dual fuel mode fuelled with Calophyllum Inophyllum oil methyl ester and Babul wood chips derived producer gas. References [1]

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(a)

(b)

(c)

Fig. 1 Photograph of calophyllum inophyllum (a) tree, (b) fruits and (c) seeds

Fig. 2 Photograph of babul wood pieces

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Stirring action in Acid Treatment

Glycerin settlement in Acid Treatment

Stirring action in Base Treatment

Settlement of glycerin after Base Treatment

Clear water in water washing

Final biodiesel

Soap obtained in water washing process

Fig. 3 Conversion process of calophyllum inophyllum raw oil to biodiesel 1

CIME 20

Methanol Content (% V/V)

0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 35

55

75

95

115

135

155

175

Flash Point (0C)

Fig. 4 Methanol content (% V/V) in CIME 20 blend vs. Flash point (0C)

195

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Fig. 5 Photograph of downdraft gasifier

All Dimensions are in mm

Fig. 6 Layout sketch of different combustion chambers.

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Hemi-spherical chamber

Shallow depth chamber

Toroidal chamber

Toroidal re-entrant chamber

Shallow depth re-entrant chamber

Fig. 7 Photographs of different combustion chambers.

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Fig. 8 Schematic diagram of the experimental setup. 40

TrCC +DIESEL+P gas

HCC + CIME 20+ P gas

SCC+ CIME 20+ P gas

TCC+ CIME 20+ P gas

30

SrCC+ CIME 20+ P gas

TrCC+ CIME 20+ P gas

25

HCC+DIESEL+ P gas

BRAKE THERMAL EFFICIENCY (%)

35

20 15 10 5 0

0

1.26

2.51 (kW) BRAKE POWER

3.77

5.02

Fig. 9 Variation of Brake Thermal Efficiency with respect to Brake Power

BRAKE SPECIFIC FUEL CONSUMPTION (Kg/kW-hr)

ACCEPTED MANUSCRIPT 0.7

TrCC +DIESEL+ P gas

HCC + CIME 20+ P gas

0.6

SCC+CIME 20+ P gas

TCC+CIME 20+ P gas

SrCC+CIME 20+ P gas

TrCC+CIME 20+ P gas

0.5

HCC+ DIESEL+ P gas 0.4 0.3 0.2 0.1 0 0

1.26

2.51 BRAKE POWER (kW)

3.77

5.02

Fig. 10 Variation of Brake Specific Fuel Consumption with respect to Brake Power 600

500

EXHAUST GAS TEMPERATURE (0C)

400

TrCC +DIESEL+P gas

HCC + CIME 20+ P gas

SCC+ CIME 20+ P gas

TCC+ CIME 20+ P gas

SrCC+ CIME 20+ P gas

TrCC+ CIME 20+ P gas

HCC+DIESEL+ P gas

300

200

100

0 0

1.26

2.51 BRAKE POWER (kW)

3.77

5.02

Fig 11.Variation of Exhaust gas Temperature with respect to Brake Power

ACCEPTED MANUSCRIPT 80 70

TrCC +DIESEL+ P gas

HCC + CIME 20+ P gas

SCC + CIME 20+ P gas

TCC + CIME 20+ P gas

SrCC + CIME 20+ P gas

TrCC + CIME 20+ P gas

60 HCC+DIESEL+ P gas

50 SMOKE OPACITY (%)

40 30 20 10 0 0

1.26

2.51

3.77

5.02

BRAKE POWER (kW)

Fig. 12 Variation of Smoke Opacity with respect to Brake Power 70 60 50

TrCC +DIESEL+ P gas

HCC + CIME 20+ P gas

SCC + CIME 20+ P gas

TCC + CIME 20+ P gas

SrCC + CIME 20+ P gas

TrCC + CIME 20+ P gas

HCC+DIESEL+ P gas

HYDROCARBON (ppm)

40 30 20 10 0 0

1.26

2.51 BRAKE POWER (kW)

3.77

Fig. 13 Variation of Hydrocarbon with respect to Brake Power

5.02

ACCEPTED MANUSCRIPT 0.25

0.2

TrCC +DIESEL+ P gas

HCC + CIME 20+ P gas

SCC + CIME 20+ P gas

TCC + CIME 20+ P gas

SrCC + CIME 20+ P gas

TrCC + CIME 20+ P gas

HCC+DIESEL+ P gas CARBON MONOXIDE (%)

0.15

0.1

0.05

0 0

1.26

2.51 BRAKE POWER (kW)

3.77

5.02

Fig. 14 Variation of Carbon monoxide with respect to Brake Power 900 TrCC +DIESEL+ P gas

HCC + CIME 20+ P gas

SCC + CIME 20+ P gas

TCC + CIME 20+ P gas

SrCC + CIME 20+ P gas

TrCC + CIME 20+ P gas

800 700

OXIDE OF NITROGEN (ppm)

600 500

HCC+DIESEL+ P gas

400 300 200 100 0 0

1.26

2.51 BRAKE POWER (kW)

3.77

Fig. 15 Variation of Oxide of Nitrogen with respect to Brake Power

5.02

ACCEPTED MANUSCRIPT 9

TrCC +DIESEL+ P gas

HCC + CIME 20+ P gas

SCC + CIME 20+ P gas

TCC + CIME 20+ P gas

SrCC + CIME 20+ P gas

TrCC + CIME 20+ P gas

8 7 6

HCC+DIESEL+ P gas

CARBON DIOXIDE

5 4 3 2 1 0 0

1.26

2.51 (kW) BRAKE POWER

3.77

5.02

Fig. 16 Variation of Carbon dioxide with respect to Brake Power 90

DIESEL FUEL SAVINGS (%)

80

SCC+CIME20+P Gas

TCC + CIME 20 + P gas

HCC+CIME 20+ P gas

TrCC+CIME20+P gas

HCC+Diesel+P Gas

TrCC+Diesel+P gas

SrCC+CIME 20+P gas

70 60 50 40 30 20 10 0 0

1.26

BRAKE POWER (kW) 2.51

3.77

Fig. 17 Variation of Diesel Fuel Savings with respect to Brake Power

5.02

ACCEPTED MANUSCRIPT 18

TrCC +DIESEL+ P gas

HCC + CIME 20+ P gas

SCC + CIME 20+ P gas

16

TCC + CIME 20+ P gas

SrCC + CIME 20+ P gas

TrCC + CIME 20+ P gas

14

HCC+DIESEL+ P gas

10 8 6 4 2 0 0

1.26

2.51

3.77

5.02

BRAKE POWER (kW)

Fig. 18 Variation of Ignition Delay with respect to Brake Power 100

TRCC + Diesel + P.gas HCC + CIME 20 + P.gas

90

SCC+CIME 20 + P.gas 80

TCC+CIME 20 + P.gas SrCC+CIME 20 + P.gas

70

HEAT RELEASE RATE (J/0CA)

IGNITION DELAY (0CA)

12

TrCC+CIME 20 + P.gas 60

HCC+ Diesel + P.gas

50 40 30 20 10 0 -30

-20 -10

-10

0

10

20

30

CRANK ANGLE (DEGREES)

Fig. 19 Variation of Heat Release Rate with respect to Crank angle

40

ACCEPTED MANUSCRIPT

90

80

TRCC + DIESEL + P. gas

HCC + CIME 20 + P. gas

SCC+CIME 20 + P. gas

TCC+CIME 20 + P. gas

SrCC+CIME 20 + P. gas

TrCC+CIME 20 + P. gas

HCC+DIESEL + P. gas 70

CYLINDER PRESSURE (bar)

60

50

40

30

20

10

0 320

340

360

380

400

CRANK ANGLE (Degree)

Fig. 20 Variation of Cylinder Pressure with respect to Crank angle

420

ACCEPTED MANUSCRIPT Highlights 1. CIME 20 showed better oil characteristics. 2. BTE for CIME 20-producer gas with TrCC was 6.37% higher than diesel -HCC. 3. NOx emission for HCC-diesel was 19.9% lower than TrCC -CIME20 -P. gas 4. CIME 20-producer gas with TrCC emits 33.71% and 38.67% less HC and smoke. 5. Diesel fuel savings of 80.5% for diesel-producer gas at optimal load condition.

ACCEPTED MANUSCRIPT

Table 1.Fatty acid profile of calophyllum inophyllum biodiesel S.No Fatty acid profile

structure

CalophyllumInophyllum

1.

Oleic

C 18:1

38.58

2.

Linoleic

C 18:2

28.84

3.

Lauric

C 12:0

0.75

4.

Stearic

C 18:0

16.38

5.

Myristic

C 14:0

0.70

6.

Palmitic

C 16:0

14.3

7.

Heptadecanoic

C 17:0

0.10

8.

Palmitoleic

C 16:1

0.25

9.

Linolenic

C 18:3

0.17

Table 2. Various instruments along with ASTM method used for measuring fuel properties. Properties

ASTM

Instruments

Measuring range

Error (%)

Density bath with

Ambient to 150°C

±0.17

Ambient to 100°C

±0.1

Methods Density at 25 °C

D 1298

(kg/m3) Kinematic

Hydrometer D 445

viscosity at 40 0C

Saybolt Kinematic Viscometer

(cSt.) Calorific value

D 4809

Bomb Calorimeter

-

±1.0

Cetane number

D 613

Ignition Quality Tester

-

±1.0

Flash point (°C)

D 93

Pensky-Martens closed

Ambient to 405°C

±0.5

Ambient to 405°C

±0.5

(MJ/kg)

cup tester Fire point (°C)

D 93

Pensky-Martens closed cup tester

ACCEPTED MANUSCRIPT

Pour point (°C)

D 97

Seta Cloud and Pour Point

60°C to (-45)°C

±0.1

60°C to (-45)°C

±0.1

<0.5 mg/KOH g

±1.4

Bath Cloud point (°C)

D 2500

Seta Cloud and Pour Point Bath

Acid value

D 974

Color-Indicator Titration

Table 3. Physio-chemical properties of Calophyllum Inophyllum oil methyl ester, diesel with reference to literature data as per ASTM D6751 standard S.No.

Properties

Unit

ASTM

ASTM

Standard

Biodiesel

Diesel

CIME

CIME

Reference

20

[54]

Limits

1.

Density

Kg/m3 D 1298

840-900

835

876.8

843.6

871

2.

Viscosity

CSt

D 445

1.9-6.0

2.97

4.72

2.91

5.45

3.

Cetane No.

-

D 613

47 min.

48

51.9

50

49.16

4.

Calorific

KJ/Kg D 4809

45.64

39.88

44.13

41.59

0.182

0.76

0.22

0.91

1

10

0

4.3

2

13

2.8

2

value 5.

Acid value

D 974

0.5 max. max.

6.

Pour point

(0C)

D 97

-15 to 16

7.

Cloud

(0C)

D 2500

-3 to -12

point 8.

Flash point

(0C)

D 93

930C min 59

151.8

123

162

9.

Fire point

(0C)

D 93

-

173.2

138

N/d

10.

Methanol

%

D 93

0.2 % wt. -

0.095

0.121

N/d

content

(m/m)

at min. 130 0C flash point temp.

68

ACCEPTED MANUSCRIPT

Table 4. Complete specification of downdraft gasifier S. No.

Technical specification

Details

1.

Model no.

WBG-15

2.

Model Type

Downdraft

3.

Flow rate of gas

37.5 Nm3/hr

4.

Biomass consumption

14 kg/hr

5.

Calorific value

1000 kJ/Nm3

6.

Ash removal

Maual

7.

Fuel storage capacity

100 kg (approax)

8.

Permissible moisture content

<33% on wt.basis

9.

Gasification temperature

1200-20000C

Table 5. Physio-chemical properties of babul wood chips under both wet (Wb) and dry basis (db) S.No

Parameters

Related values

1.

Calorific value

1000 Kcal/Nm3

2.

Stoichiometric A/F ratio

1.16:1

3.

Adiabatic flame temperature

1546±25K

4.

Density

1.281 kg/m3

5.

Octane number

104

6.

Wobbe index

24.7 MJ/Sm3

ACCEPTED MANUSCRIPT

Table 6. Overall dimensions of different combustion chambers. S.No.

Combustion chambers

Dth (mm)

Hmax (mm)

Rth (mm)

Dmax (mm)

type 1.

TCC

87.50

16.41

10

53.14

2.

SCC

87.50

19.61

7.89

55.80

3.

TrCC

87.50

16.78

10.78

54.00

4.

SrCC

87.50

13.75

7.75

54.16

Table 7. Test engine complete specification S.No.

Engine Details

Specification

1.

Make and Supplier

Kirloskar Made (Apex innovations Pvt. Ltd. Maharashtra)

2.

Horse power (kW)

5.2

3.

Stroke length (mm)

110

4.

Rotation per minute (RPM)

1500

5.

No. of strokes

01

6.

No. of cylinders

04

7.

Compression ratio (CR)

16:1

8.

Bore Diameter (mm)

114

9.

Injector opening pressure

200-210

(bar) 10.

Injection timing (0bTDC)

230

ACCEPTED MANUSCRIPT

Table 8. Technical specification of AVL 437 Smoke Meter Parameter

Measuring range

Resolution

Accuracy

Error (%)

Smoke opacity

0-100%

0-1%

±1%

±1.0

Table 9. Technical specification of AVL 444 Multi-gas analyser Param

Measuring

eters

range

CO2

0-20 % vol.

CO

0-10 % vol.

Resolution

Accuracy

Error (%)

0.1 % vol.

< 10 % vol. ± 0.5 vol.

±0.01

≥ 10 % vol. ± 5 vol.

kg/hr

< 0.6 % vol. ± 0.03 % vol.

±0.3

0.01 % vol.

≥ 0.6 % vol. ± 5 % vol. NOx

0-22 % vol.

0.1 % vol.

< 2 % vol. ± 0.1 % vol.

±0.1

≥ 2 % vol. ± 5 % vol. HC O2

0-20000 (ppm)

≤ 2000:1 (ppm) vol.

< 200 (ppm) vol. ± 10 (ppm) vol.

vol.

> 2000:10 (ppm) vol.

≥ 200 (ppm) vol. ± 5 % vol.

0-5000 (ppm)

1 (ppm) vol.

< 500 (ppm) vol. ± 50 (ppm) vol.

±10 ppm -

≥ 500 (ppm) vol. ± 10 % vol.

vol.

Table 10.Uncertainty analysis at optimal loading condition S. No

Measurement

Range

Resolution

Uncertainty (%)

1

CO

0-10 vol. %

±0.01 vol %

±0.04

2

NOx

0-22 vol. %

±1 vol %

±0.45

3

CO2

0-20 vol. %

±0.1 vol %

±0.07

4

Smoke

0-100 vol. %

±1 %

±0.1

5

HC

0-20000 ppm

±2 ppm

±2

6

BTE

-

±0.2 %

±0.66

7

EGT

0-1200 0C

±0.2 0C

±0.07

ACCEPTED MANUSCRIPT

8

Load

0-500 Nm

±0.1 Nm

±0.3

9

Speed

0-10000 RPM

±1 RPM

±0.1

10

Time

-

±0.1 Sec

±0.1

11

Fuel flow

0.5-36 L/hr

±0.01 L/hr

±0.68

12

Air Flow

0.25-7.83 Kg/min

±0.07 Kg/min

±2