Study On Production Of Clean Biofuel Using Bio-syngas

Biomass is a rich, environmentally friendly and renewable resource which is globally available, and can be thermochemically converted to high-quality liquid fuels or high value-added chemicals. One of the most promising options to produce biofuels is the so-called biomass-to-liquids (BTL) route, which can be alternatives to conventional gasoline and diesel, and resolve energy crisis. The BTL route is an important area of biomass energy research. Main work was as follows:1. Studies on catalysts in bio-fuels synthesis of mixed alcohols and FT fuels.(1). A series of catalysts containing CuCoFeZnMoK were applied for synthesizing low carbon mixed alcohols from bio-syngas. The maximum mixed alcohols yield can reach 640 g/(kgcat h) with the C2+ alcohols (C2-C6) distribution of 85.7 wt% over the catalyst prepared by coprecipitation, in the test conditions T=250-350℃, P=40-70atm.(2). A mixture oxide catalyst of FeCuZnAlK was successfully applied for high efficient production of the clean biofuels from two different bio-syngases derived the biomass gasification and the bio-oil reforming (defined as BGS and BRS). The maximum carbon conversion 94% was obtained during the tests. The maximum biofuels yield using BGS reached about 1.59 kg fuels/(kgcat h) with a contribution of 0.57 kg alcohols/(kgcath) and liquid hydrocarbons (LHC) of 1.02 kg LHC/(kgcath), and the biofuels possessed a high heat value of 40-42 MJ/kg.2. Producing low carbon mixed alcohols from bio-syngases.A mixture catalyst containing CuCoFeZnMoK multiple active elements were applied for synthesizing low carbon mixed alcohols from bio-syngases. Some important reaction parameters including different biomass-based syngases, temperature, pressure, gas hourly space velocity were investigated. The maximum mixed alcohols yield can reach 640 g/(kgcat h) with the C2+ alcohols (C2-C6) distribution of 85.7 wt% over the catalyst prepared by coprecipitation, in the test conditions T=320℃, P=7.0 MPa and GHSV=20000 h-1. The maximum mixed alcohols yield from the bio-oil reforming syngas can reach 260 g/(kgcat h)with the C2+ alcohols (C2-C6) distribution of 89.3wt% and the carbon conversion of 28.9% in the test conditions T-335℃, P=7.0 MPa and GHSV=20000 h-1.3. Producting liquid hydrocarbons and mixed alcohols from the bio-syngases. A mixture oxide catalyst of Fe1.5Cu1Zn1Al1K0.117 was successfully applied for high efficient production of the clean biofuels from two different bio-syngases derived the biomass gasification and the bio-oil reforming (defined as BGS and BRS). The maximum biofuels yield using BGS reached about 1.59 kg fuels/(kgcat h) with a contribution of 0.57 kg alcohols/(kgcat h) and liquid hydrocarbons (LHC) of 1.02 kg LHC/(kgcath), which is very close to the methanol yield 1.3-1.5 kg/(kgcata h) typically obtained in the commercially practiced methanol synthesis process. The biofuels from BGS possessed a high heat value of 40-42 MJ/kg. The selectivity toward C2+ alcohols (C2-C6) was obtained with a 70 wt%-90 wt% in alcohols products, and liquid hydrocarbons (C5+) in hydrocarbons products ranges from 60 wt%-71 wt%.The biofuels synthesis using the bio-oil reforming-based syngas (BRS) and the FeCuZnAlK catalyst mainly produced the liquid hydrocarbons, mixed alcohols and gas hydrocarbons within the investigated synthesis ranges:T=300-370℃, P=5.0-7.0 MPa and GHSV=10000-20000 h-1. The maximum biofuels yield obtained from BRS was about 0.63 kg biofuels/(kgcat h) with a contribution of 0.40 kg alcohols/(kgcat h) mixed alcohols and 0.23 kg LHC/(kgcat h) liquid hydrocarbons within our investigated range. The heat value of the biofuels derived from the bio-oil reforming-based syngas was in the range of 35.27-37.28 MJ/kg, which was lower than that from the BGS.4. Investigation of some important elemental reactions and technology evaluation of bio-fuels via FT synthesis.Some important elemental reactions involved in the biofuels synthesis, including the water-gas shift reaction, reverse water-gas shift reaction, decomposition of alcohols and hydrocarbons, and methanation were also investigated in detail. Basic characters of the catalyst were also studied by XRD, ICP-AES, TPR and BET; the results contributed to the optimization of reaction parameters and understanding of reaction mechanisms. Moreover a technology and economic evaluation of FT bio-fuels was also made.