Characterization and Gasification using- Jatropha Curcas Seed Cake KSrividhya P.1,*, Tamizharasan T.1, Jayaraj S.2, Muralledharan C.2 1Department of Mechanical Engineering, Periyar Maniammai University, Vallam, Thanjavur 2Department of Mechanical Engineering, National Institute of Technology, Calicut *Email ID: sriara_99@yahoo.com
Abstract This paper deals with investigation on Jatropha seed cake (non edible de-oiled cake) for thermo chemical conversion processes (combustion, gasification) for thermal application. Physical and chemical characteristics analysis on seed cake were done and the data has been reported in this paper. The thermal gravimetric analysis (TGA) has been done on it using a thermal analyzer from room temperature to 1000°C in air, nitrogen atmosphere at a heating rate of 20°C/min. It showed that it took temperature of 243°C for ignition and there was a very little fraction of thermal decomposition occurred after 530°C with burn out residues of 11.68% in air atmosphere. Gasification studies were conducted with laboratory model downdraft gasifier using Jatropha seed cake for thermal application. The performance of the feedstock was determined by measuring gasifier zone temperature sensing with thermocouple throughout the main zones of the gasifier, at the gasifier outlet and also the flame temperature of the producer gas at burner. The maximum temperature of the bottom flame was recorded as 910° C and the flame length was about from lft to 1.5 ft with yellowish colour. The studies revealed that it is a good feed stock for gasification and combustion. Because of its fuel characteristics this can be compared with other woody biomasses. Top Keywords Jatropha, Deoiled cake, TGA analysis, Gasification, Flame temperature. Top |
Introduction Biomass sources are the most promising, sustainable and least polluting among the other renewable energy sources. The potential for greenhouse gases production is less using the biomass energy. Biomass has attributes very similar to fossil fuels, but having less energy density with relatively much less emission problems. Biomass still remains an important energy source and contributes 14% of the world energy and 38% of energy in developing countries [1]. |
There is a growing interest in Jatropha Curcas as a biodiesel “miracle tree” to help alleviate the energy crisis and generate income in rural areas of developing countries. The production of oil from Jatropha seed inevitably results in by product of press cake with a high percentage of crude protein (58–60%), making it unsuitable for animal feed. A one-ton per day biodiesel plant, produces 2.5 to 3 tons of seed cake. Further treatment is important for detoxifying the seed cake through a combination of heat treatment and solvent extraction, but apparently it was not an economically viable option for commercial production [2-3]. |
The thermo chemical processes such as pyrolysis, gasification and combustion are the most attractive and practical as far as the energy recovery from the biomass is concerned [4], being the combustion responsible for about a 97% of the production of Bio-energy in the world [1]. Thermal processes are the option most widely used for the treatmensssst of the waste coming from the agro-industries for the effective utilization of energy conversion as well as waste management. |
To design the correct systems for thermo chemical treatment, it is necessary to know deeply the different states and transitions that take place in the biomass wastes as the temperature varies [5]. The information obtained from the TGA in the case of fuels like carbon can be used to estimate the behavior of the combustion in industrial scale. The analysis of the characteristics of the combustion allows obtaining the burning profile of the fuel, defined as the representation of weight loss versus temperature in an oxidizing atmosphere [6]. |
In this work, TGA techniques and other characterization tests have been used to evaluate the thermal behavior of the material in an oxidizing atmosphere and thermal performance analysis was carried out in downdraft gasifier by sensing the temperature of zones, exit producer gas and flame temperature. |
Top Materials and Experiments Raw Material Jatropha seed cakes were collected from Swaraj Biodiesel Production Centre, where research and development works are going on for Biodiesel production from different non edible seed's oil, located at Tiruchuli, Tamilnadu. Oils required for biodiesel production are being extracted from seeds by mechanical oil expeller, usually generated seed cake consist of crushed seed shell and kernel. Two types of seed cakes were collected from there. One has been collected freshly at the time of oil extraction, which still contains about 11% oil. Another one, which were dried and being stored for more than 3 months, contain about 5% oil. The freshly collected seed cakes have been grinded to make powder and then they have been converted into handmade densified cake with more or less uniform size, by mixing enough water with them and they were being dried more than 5 days in direct sun light. Finally the densified cakes were with the weight ranges between 150–175 gm. Stored seed cake could be used as such without involving any densifying process for both combustion and gasification process.Figures 1 and 2 shows the Jatropha seed cake. Combustion in Tga/Dta The characterization of the material analysis would be carried out: heating value, ultimate analysis, proximate analysis. Calorific values will be measured using Bomb calorimeter. C, H, N, S contents in the fuels can be analyzed using an Elemental Analyzer. The moisture content of the samples will be obtained by drying till constant weight in a muffle furnace. Ash content and volatile matter can be determined after slow combustion of the samples in it. Finally, the fixed carbon content would be calculated by difference. All the analysis can be measured according to the normalized methods of ASTM. TGA analysis was carried out in a SDT Q600V8.3 instrument (CECRI, Karaikudi) at heating rate of 20°C/min in air atmosphere in the temp range of room temp to 1000°C. From the weight loss (TG) process, derivative thermo gravimetric (DTG) and difference in thermal analysis (DTA) curves can be plotted. For the determination of the combustion profiles of the material, dynamic experiments have been done in air and nitrogen atmosphere in a TG/DTA SDT Q600 thermal analyzer. The chemical and elemental analyses and calorific value are reported in table 1. Experimental Set Up of Gasifier The experimental set up consists of downdraft gasifier (made for thermal/cooking purpose) with a cylindrical structure, blower, motor for water circulation for gas purification and burner. The main body made from 10.3 cm diameter mild steel pipe with a total length of 1m. The cylindrical structure surrounded with insulation of cotton sponge is 4.7 cm. feeding of biomass material or the solid fuel into the gasifier is carried out through the top of the gasifier. The size of the biomass material used was equivalent to 3.5*2*1.5 cm. The air is sucked through a 1.3 cm diameter nozzle that is positioned about 66 cm from the top. The figures 3 and 4 illustrate the experimental setup of the 1kW and 20kW gasifiers erected in the Periyar Maniammai University vallam, Thanjavur, Tamilnadu, India which was utilized for the experimental purposes. Six k type thermocouples are used to measure the temperature distribution inside the gasifier. The temperatures are measured at intervals of 2 min to record the thermo chemical conversion phases: drying, combustion, reduction and exit producer gas temperature. Another one measured the flame temperature of the producer gas at burner. Top Results and Discussion The ultimate and proximate analysis of the fuels are the main tool for predicting the gas gross calorific value composition and temperature limits of the gasifier through mass and energy balances. The GCV of seed cake was estimated as 18.2 MJ/kg. |
A preliminary investigation of physicochemical characteristics of this residue revealed that this has low moisture content (<10w/w%) favoring their conversion via gasification, as they would probably ignite easily without the necessity of excessive heat for moisture evaporation. |
This residue presents low ash content (6.5 w/w%) characteristic for lignocellulosic materials. Their high volatile (>75 w/w%) indicates their attractive potential for exploitation through gasification. Fuels with high volatile matter content are more reactive, and therefore can be converted more easily into gas while producing less char [7]. |
Tga Analysis The three main biomass components are hemicelluloses, cellulose and lignin that decompose in different temperature ranges during thermal treatment. Many studies provide evidence of the evolution of the volatile compounds, primarily due to the decomposition of hemicelluloses and cellulose followed by lignin during TGA [7, 8]. As a result, temperature between 200 to 300° C released lighter volatiles due to the easy breakdown of hemicelluloses and cellulose [8, 9]. Under an ordinary heating rate, the hemicelluloses degradation is completed at 350°C and cellulose between 250 and 500°C [10]. Lignin, on the other hand, is more thermally stable than hemicellulose/cellulose, and as a result, lignin pyrolysis to heavier volatiles spreads almost the entire temperature range from 150 to 900°C, with no sharp peak in weight loss [10, 11]. Figure 5 shows TGA Graph between weight loss (%) and temperature. Figure 6 shows DTG graph between weight loss rate and temperature Weight loss (w/w %) and rate of weight losses (w/w%) during the TGA analysis of seed cake are depicted in figure 5 & 6. The thermal decomposition of seed cake gave three main peaks in the temperature range of 50–500°C, probably due to light and heavy volatile release. The removal of moisture takes place between 30 to 183°C with a maximum weight loss of 9.47%. Afterwards, the first peak, which could represent the yield of the lighter volatiles with a maximum value weight loss of 44.73% at 360°C,wt loss rate. The second and third peaks represent the heavier volatiles decomposition (cellulose and lignin), showing a total weight loss of 33.59%. The char residue is oxidized above 530°C. The remaining solid at 1000°C (ash) has a value of 11.68% that shows a higher ash content than ash content determined by the chemical analysis. This is possibly related to the cylindrical shape of the burning chamber, which may influence air easily reaching the fuel at the bottom, the combustion needs longer time to complete the burnout stage till the ash residues coincide to that of the chemical analysis [12]. Top Conclusion According to the results obtained and the analysis of the characterization of the material, it can be concluded that: |
The moisture content of the seed cake (around 9%) makes it viable to keep the combustion process, but there is no necessity to use an additional fuel. The percentage of carbon in material studied is within the normal range, which is viable for thermo chemical energy conversion. As for the nitrogen, sodium and hydrogen contents, the values obtained show that, problems related to the emissions nitrogen oxides, corrosion and soiling are not likely to appear. As far as the ash content is concerned, there is no big problem arise, but it is necessary to take care during gasification process. |
Moreover, taking into account the different combustion profiles of the seed cake, it can be concluded that: In this study, TGA-DTA experiments were performed on a material in 20°C heat transfer rate at air atmosphere in thermal analyzer to analyze its suitability as a fuel in gasifier. Some quantitative characteristics during dewatering, volatilization char burning and char burn out stages are listed and compared. Fuel shows volatilization as the predominant in combustion process, almost medium char conflagration stage and longer burn off stage. The maximum weight loss occurs at 320°C with maximum weight loss rate of 18.68%. There was a only very little fraction of thermal decomposition occurred after 530°C with burn out residues of 10.68%. It shows that there is no higher temperature required for thermo chemical energy conversion process due to its low ignition temperature (202°C).The maximum temperature of the flame was recorded as 910° C and the flame length was about from 1ft to 1.5 ft with orange Colour in 1 Kw downdraft gasifier during operation. The overall conversion efficiencies found through water boiling test were approximately 63.5% and 63% for seed cake and wood biomass(Neem) respectively in 20kW gasifier. The studies revealed that it is a good feed stock for gasification and combustion, due to its fuel characteristics, which was comparable to wood. |
Top Figures | Figure 1.: Jatropha seed cake
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| | Figure 2.: Densified Jatropha seed cake
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| | Figure 3.: Photograph of 1kW gasifier
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| | Figure 4.: Photograph of 20kW gasifier
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| | Figure 5.: TGA Graph between weight (%) and temperature
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| | Figure 6.: DGA graph between weight loss rate and temperature
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Tables | Table 1:: Physical-chemical characteristics
| | Proximate analysis (% weight) | | Ultimate analysis (%weight) | | | Moisture content (wet basis) | 8.5 | Carbon | 49.050 | | Volatile matter (dry basis) | 75.13 | Hydrogen | 6.262 | | Fixed carbon (dry basis) | 18.89 | Nitrogen | 3.173 | | Ash content (dry basis) | 5.89 | Sulphur | 0.000 | | VM/FC | 3.97 | Oxygen by diff | 35.715 | | | Chlorine | 0.1 | | | HHV (MJ/Kg) | 18.2 |
| | | Table 2:: Summary of TGA Analysis
| | Parameters | Temperature Range(°c) | | 1 | Atmosphere | Air | | 2 | Heating range | Room temp – 1000 | | 3 | Heat transfer rate | 20 | | 4 | Dewatering | 183.35 | | 5 | Ignition | 243 | | 6 | Volatilitation and burning | 183.35–361.05 | | 7 | Transition period | 361.05–499.90 | | 8 | Char burning | 499.90–530.88 | | 9 | Burn out residue | 12.21 |
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