Browsing by Subject "pyrolysis"
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Item Biofuels from Corn Stover: Pyrolytic Production and Catalytic Upgrading Studies(2013-01-15) Capunitan, Jewel AlviarDue to security issues in energy supply and environmental concerns, renewable energy production from biomass becomes an increasingly important area of study. Thus, thermal conversion of biomass via pyrolysis and subsequent upgrading procedures were explored, in an attempt to convert an abundant agricultural residue, corn stover, into potential bio-fuels. Pyrolysis of corn stover was carried out at 400, 500 and 600oC and at moderate pressure. Maximum bio-char yield of 37.3 wt.% and liquid product yield of 31.4 wt.% were obtained at 400oC while the gas yield was maximum at 600oC (21.2 wt.%). Bio-char characteristics (energy content, proximate and ultimate analyses) indicated its potential as alternative solid fuel. The bio-oil mainly consisted of phenolic compounds, with significant proportions of aromatic and aliphatic compounds. The gas product has energy content ranging from 10.1 to 21.7 MJ m-3, attributed to significant quantities of methane, hydrogen and carbon dioxide. Mass and energy conversion efficiencies indicated that majority of the mass and energy contained in the feedstock was transferred to the bio-char. Fractional distillation of the bio-oil at atmospheric and reduced pressure yielded approximately 40-45 wt.% heavy distillate (180-250oC) with significantly reduced moisture and total acid number (TAN) and greater energy content. Aromatic compounds and oxygenated compounds were distributed in the light and middle fractions while phenolic compounds were concentrated in the heavy fraction. Finally, hydrotreatment of the bio-oil and the heavy distillate using noble metal catalysts such as ruthenium and palladium on carbon support at 100 bar pressure, 4 hours reaction time and 200o or 300oC showed that ruthenium performed better at the higher temperature (300oC) and was more effective than palladium, giving about 25-26% deoxygenation. The hydrotreated product from the heavy distillate with ruthenium as catalyst at 300oC had the lowest oxygen content and exhibited better product properties (lower moisture, TAN, and highest heating value), and can be a potential feedstock for co-processing with crude oils in existing refineries. Major reactions involved were conversion of phenolics to aromatics and hydrogenation of ketones to alcohols. Results showed that pyrolysis of corn stover and product upgrading produced potentially valuable sources of fuel and chemical feedstock.Item Conversion of MixAlco Process Sludge to Liquid Transportation Fuels(2012-02-15) Teiseh, Eliasu 1973-About 8 tons of dry undigested solid waste is generated by the MixAlco process for every 40 tons of food residue waste fed into the process. This MixAlco process produces liquid fuels and the sludge generated can be further converted into synthesis gas using the process of pyrolysis. The hydrogen component of the product synthesis gas may be separated by pressure swing adsorption and used in the hydrogenation of ketones into fuels and chemicals. The synthesis gas may also be catalytically converted into liquid fuels via the Fischer-Tropsch synthesis process. The auger-type pyrolyzer was operated at a temperature between 630-770 degrees C and at feed rates in the range of 280-374 g/minute. The response surface statistical method was used to obtain the highest syngas composition of 43.9 +/- 3.36 v % H2/33.3 +/- 3.29 v % CO at 740 degrees C. The CH4 concentration was 20.3 +/- 2.99 v %. For every ton of sludge pyrolyzed, 5,990 g H2 (719.3 MJ), 65,000 g CO (660 MJ) and 21,170 g CH4 (1055.4 MJ) were projected to be produced at optimum condition. At all temperatures, the sum of the energies of the products was greater than the electrical energy needed to sustain the process, making it energy neutral. To generate internal H2 for the MixAlco process, a method was developed to efficiently separate H2 using pressure swing adsorption (PSA) from the synthesis gas, with activated carbon and molecular sieve 5A as adsorbents. The H2 can be used to hydrogenate ketones generated from the MixAlco process to more liquid fuels. Breakthrough curves, cycle mass balances and cycle bed productivities (CBP) were used to determine the maximum hydrogen CBP using different adsorbent amounts at a synthesis gas feed rate of 10 standard lpm and pressure of 118 atm. A 99.9 % H2 purity was obtained. After a maximum CBP of 66 % was obtained further increases in % recovery led to a decrease in CBP. The synthesis gas can also be catalytically converted into liquid fuels by the Fischer-Tropsch synthesis (FTS) process. A Co-SiO2/Mo-Pd-Pt-ZSM-5 catalyst with a metal-metal-acid functionality was synthesized with the aim of increasing the selectivity of JP-8 (C10-C17) fuel range. The specific surface areas of the two catalysts were characterized using the BET technique. The electron probe microanalyzer (with WDS and EDS capabilities) was then used to confirm the presence of the applied metals Co, Mo, Pd and Pt on the respective supports. In addition to the gasoline (C4-C12) also produced, the synthesis gas H2:CO ratio was also adjusted to 1.90 for optimum cobalt performance in an enhanced FTS process. At 10 atm (150 psig) and 250 degrees C, the conventional FTS catalyst Co-SiO2 produced fuels rich in hydrocarbons within the gasoline carbon number range. At the same conditions the Co-SiO2-Mo-Pd-Pt/HZSM-5 catalyst increased the selectivity of JP-8. When Co-SiO2/Mo-Pd-Pt-HZSM-5 was used at 13.6 atm (200 psig) and 250 degrees C, a further increase in the selectivity of JP-8 and to some extent diesel was observed. The relative amounts of olefins and n-paraffins decreased with the products distribution shifting more towards the production of isomers.Item Elucidating the solid, liquid and gaseous products from batch pyrolysis of cotton-gin trash.(2009-05-15) Aquino, Froilan LudanaCotton-gin trash (CGT) was pyrolyzed at different temperatures and reaction times using an externally-heated batch reactor. The average yields of output products (solid/char, liquid/bio-oil, and gaseous) were determined. The heating value (HV) of CGT was measured to be around 15-16 MJ kg- 1 (6500-7000 Btu lb-1). In the first set of tests, CGT was pyrolyzed at 600, 700, and 800?C and at 30, 45, and 60 min reaction period. The maximum char yield of 40% by weight (wt.%) was determined at 600?C and 30 min settings, however, the HV of char was low and almost similar to the HV of CGT. A maximum gas yield of 40 wt.% was measured at 800?C and 60 min and the highest liquid yield of 30 wt.% was determined at 800?C and 30 min. In the modified pyrolysis test, the effects of temperature (500, 600, 700, and 800?C) on the product yield and other properties were investigated. The experiment was performed using the same reactor purged with nitrogen at a rate of 1000 cm3 min-1. Gas yield increased as temperature was increased while the effect was opposite on char yield. The maximum char yield of 38 wt.% was determined at 500?C and 30 min. The char had the largest fraction in the energy output (70-83%) followed by gas (10-20%) and bio-oil (7- 9%). Maximum gas yield of 35 wt.% was determined at 800?C. The average yield of CO, H2 and total hydrocarbons (THC) generally increased with increased temperature but CO2 production decreased. Methane, ethane, and propane dominated the THC. The bio-oil yield at 600?C was the highest at about 30 wt.% among the temperature settings. The HV of bio-oil was low (2-5 MJ kg-1) due to minimal non-HC compounds and high moisture content (MC). A simple energy balance of the process was performed. The process was considered energy intensive due to the high amount of energy input (6100 kJ) while generating a maximum energy output of only 10%. After disregarding the energy used for preparation and pyrolysis, the energy losses ranged from 30-46% while the energy of the output represent between 55-70% of the input energy from CGT.Item Optimization of Jatropha Oil Extraction and Its By-Product Utilization by Pyrolysis Method(2012-08-20) Kongkasawan, Jinjuta 1987-Since the price of fossil fuel has increased, petroleum resources have been restricted and the environmental effects have been of great concern. Biofuel has been considered to be a good solution because it is a clean, non-pollutant and a renewable energy. Biodiesel is one alternative energy that plays a major role in the energy industry. So, the development of biofuel process is more interesting. Jatropha curcas L. is considered as an alternative energy source in order to help solve the energy crisis. The purpose of this research is to investigate the optimum condition of Jatropha seed extraction via a screw press and its by-product utilization by a pyrolysis method for achieving the maximum mass conversion and energy recovery. In this study, Jatropha seeds were first extracted by a screw press with different discharge aperture sizes, namely, number 4 (4.0 mm), 8 (7.0 mm), and 10 (10.5 mm). The by-product obtained from a screw press was then performed pyrolysis runs at the operating temperatures of 400, 500, and 600 degrees C. Results revealed that the optimum condition was achieved when using discharge aperture number 8 (7.0 mm) for a screw press and performing the pyrolysis of the by- product at 500 degrees C. The mass conversion efficiency of 35.8% refined oil, 21.8% bio-char, 14.6% bio-oil, and 11.7% syn-gas were obtained. Therefore, the utilization of by-product using a pyrolysis can enhance the effectiveness of Jatropha oil extraction with only 16% mass losses occurred. In addition, the gross heating values of the products were observed as 39.6 MJ/kg for the refined oil, 35.1 MJ/kg for the bio-oil, 27.5 MJ/kg for the bio-char, and 2.1 MJ/kg for the syn-gas. Due to a high mass conversion efficiency and energy content of Jatropha products, Jatropha has the potential to serve as an alternative energy source.Item Pyrolysis and ignition behavior of coal, cattle biomass, and coal/cattle biomass blends(2009-05-15) Martin, Brandon RayIncreases in demand, lower emission standards, and reduced fuel supplies have fueled the recent effort to find new and better fuels to power the necessary equipment for society?s needs. Often, the fuels chosen for research are renewable fuels derived from biomass. Current research at Texas A&M University is focused on the effectiveness of using cattle manure biomass as a fuel source in conjunction with coal burning utilities. The scope of this project includes fuel property analysis, pyrolysis and ignition behavior characteristics, combustion modeling, emissions modeling, small scale combustion experiments, pilot scale commercial combustion experiments, and cost analysis of the fuel usage for both feedlot biomass and dairy biomass. This paper focuses on fuel property analysis and pyrolysis and ignition characteristics of feedlot biomass. Deliverables include a proximate and ultimate analysis, pyrolysis kinetics values, and ignition temperatures of four types of feedlot biomass (low ash raw manure [LARM], low ash partially composted manure [LAPC], high ash raw manure [HARM], and high ash partially composted manure [HAPC]) as well as blends of each biomass with Texas lignite coal (TXL). Activation energy results for pure samples of each fuel using the single reaction model rigorous solution were as follows: 45 kJ/mol (LARM), 43 kJ/mol (LAPC), 38 kJ/mol (HARM), 36 kJ/mol (HAPC), and 22 kJ/mol (TXL). Using the distributed activation energy model the activation energies were 169 kJ/mol (LARM), 175 kJ/mol (LAPC), 172 kJ/mol (HARM), 173 kJ/mol (HAPC), and 225 kJ/mol (TXL). Ignition temperature results for pure samples of each of the fuels were as follows: 734 K (LARM), 745 K (LAPC), 727 (HARM), 744 K (HAPC), and 592 K (TXL). There was little difference observed between the ignition temperatures of the 50% blends of coal with biomass and the pure samples of coal as observed by the following results: 606 K (LARM), 571 K (LAPC), 595 K (HARM), and 582 K (HAPC).