Studies On The ReSER-COG Of Hvdrogen Production And The Technology Evaluation

China has an abundant resource of the coke oven gas(COG), which is a kind of industrial by-product gas.The study of the lowcost, efficient and scaled hydrogen production technology from COG has significant meaning in theoretically and practically. The problems of a traditional physical method of COG hydrogen production technologies, such as pressure swing adsorption (PSA) process, are low hydrogen production ratio and resource utilization. In this thesis, on the basis of COG hydrogen production technologies with chemical process, a reactive sorption-enhanced reforming process of simulated coke oven gas (ReSER-COG) has been proposd as a new technique. The research results have great significant for efficient hydrogen production from COG with energy conservation and CO2emission control.Firstly, in order to obtain the optimized reaction conditions of ReSER process of C2/C3in the COG, the thermodynamic calculation was calculated under different process operating conditions respectively. The calculation results provide a guide of selection of the experiment conditions of the ReSER-COG hydrogen production. The calculation results showed that the optimized reaction conditions are at the steam to carbon molar ratio of4, calcium to carbon molar ratio of2.5, reaction temperature between200℃to650℃and system pressure between0.1MPa to1.8MPa respectively. The products with H2content of95vol%included were obtained under the optimized reaction conditions. The H2content in the products was increased with the increasing of reaction temperature or CO2adsorption rate. Among the studied hydrocarbons, the alkenes with the same C number were more inclined to perform ReSER process than that of alkanes. The raw material with more C number was more easily to carry outReSER process.Secondly, by using the prepared Ni-nano-CaO/Al2O3complex catalyst under the optimized reaction conditions of ReSER process, the ReSER-COG process of the desorbed gas (DG) which comes from COG after once of PSA process for hydrogen purification was investigated in a laboratory-scale fixed-bed reactor. As the results showed:the hydrogen concentration reaches95.8%at a reaction temperature of600℃. This reaction temperature was approximately200℃lower than that of COG steam reforming process without reaction sorption-enhanced effect. The C2+are easily to occur ReSER process than CH4at the same reaction conditions, which proved the result of the thermodynamic calculation of ReSER hydrogen production process of C2/C3. The existing of C2+are favor to increase of the H2concentration in products. The reaction temperature was50℃decreased when simulated DG with C2+was used, as opposed to when COG without C2+was used. The influence to the CH4conversion arising from C2+was eliminated through increasing the steam to mathane mole ratio. The complex catalyst has a better resistance of coking during the ReSER-COG process when C2+gas was presented.According to the characteristics of various reaction components such as CH4, CO, CO2were contained in the COG simultaniously, and on the basis of the hypothesis that the CH4steam reforming reaction is the control step, the intrinsic reaction kinetics of ReSER-COG process was established. The reaction rates of ReSER-COG process were investigated under the steam to carbon molar ratio of4, reaction temperature between560℃to680℃, reaction space velocity between0.0417～0.0105gmin-ml"1and system pressure at0.1MPa. The mean relative fluctuation of the establishment model is4.58%. The ReSER-COG activation energy is95kJ/mol. It explained the reason of higher methane conversion rate could be obtained at lower reaction temperature in the ReSER-COG process.At last, a systematic ReSER-COG continuous hydrogen production process was established by using simulation software of Aspen Plus. Under the former studies optimized reaction conditions of steam to carbon molar ratio of4, calcium to carbon molar ratio of2.75and reaction temperature of600℃, the maximum hydrogen production rate of the ReSER-COG process is1.8Nm3H2/Nm3COG, the highest energy conversion efficiency is76.3%, the lowest water consumption is0.8kg H2O/Nm3H2, and the lowest raw material consumption is0.56Nm3COG/Nm3H2. The COG energy conversion efficiency with CO2removal exhaust gas by hot potash absorption is3.7%decrease with15%higher energy consumption than that of the COG energy conversion efficiency without CO2removal. The comparison of the technical performances such as hydrogen production rate and energy conversion efficiency between different hydrogen production technologies showed that ReSER-COG hydrogen production technology has the strongest technical advantages.The studies of the ReSER-COG hydrogen production technology in this thesis provide a new theoretical basis for lowcost, large-scale and efficient hydrogen production from COG.