IS THERMO-CHEMICAL CONVERSION PROCESS OF BIOMASS – A ROUTE FOR FUEL CELL APPLICATION?

摘要

The paper attempts to justify the use of the renewable hydrogen rich syn-gas generation for fuel cellrnapplication. Air gasification process generates producer gas with about 20 % hydrogen and an average gasificationrnefficiency of about 80 %, captures 35 – 40 grams of hydrogen from biomass. Producer gas as a fuel in internalrncombustion engines and gas turbines has been extensively researched and also commercialized (1). In the recentrntimes, with established gasification process, oxy-steam gasification process developed at the Indian Institute ofrnScience provides an opportunity to generate hydrogen rich syn-gas amounting to about 100 g of hydrogen per kg ofrnbiomass (2). The enhanced hydrogen yield is essentially due to the presence of steam enhancing the char-steamrnreaction process. The process parameters for oxy-steam gasification addresse the need to meet various combination ofrnCO and H_2 in syngas for applications in FT and DME. Coupled with steam- reforming, the process provides a routernfor enriching the hydrogen fraction in syngas. With about 50% hydrogen and 25 % carbon monoxide in the gas andrnhaving a calorific value of 9 MJ/kg, the fuel is good for SOFC applications with very limited cell ouput derating. Thernpaper also presents the other process coupled with the gasification system to address hydrogen generation for meetingrnPEM quality. Mass and energy balance for the oxy-steam process towards generating hydrogen rich syn-gas andrnsubsequently the process involved in the generation of 99.99 % pure hydrogen is evaluated. An insight into technoeconomicrnfeasibility of such an operation is also brought about comparing with other renewable process towardsrngenerating hydrogen.