tailieunhanh - Clean Energy Systems and Experiences Part 8

Tham khảo tài liệu 'clean energy systems and experiences part 8', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 98 Clean Energy Systems and Experiences Rodrigues and co-workers 46-50 developed a detailed mathematical model of the abovedescribed PSSER process to simulate its performance for producing fuel-cell grade hydrogen. The model simulations were also used to investigate several new operational schemes for improving the performance of the PSSER process higher conversion and purer H2 . They included a introduction of a purge step with a mixture of N2 and H2 prior to steam purge and b packing different sections three of the sorber-reactor using different catalyst-sorbent ratios the sections at the feed and the product ends being lean in sorbent and operating the sections at different temperatures the product -end section having a lower temperature. Thermal swing sorption enhanced reaction TSSER process A rapid thermal swing sorption enhanced reaction TSSER process for low temperature 520 - 590 C SMR was recently designed by Sircar and co-workers 51 - 53 . The process employed a pair of fixed bed sorber-reactors and it could directly produce fuel-cell grade H2 using K2CO3 promoted hydrotalcite as the CO2 chemisorbent in the process. The process uses two cyclic steps a sorption-reaction step where a mixture of H2 O and CH4 is fed at a pressure of bar and a temperature of 490 C into a fixed-bed reactor which is packed with an admixture of the SMR catalyst and the chemisorbent and which is pre-heated to 520 -590 C. The effluent from the reactor is fuel-cell grade H2 at feed pressure. b thermal regeneration step where the reactor is simultaneously depressurized to nearambient pressure and counter-currently purged with superheated steam at ambient pressure and at 520 - 590 C followed by counter-current pressurization of the reactor with steam at 520 - 590 C to the feed pressure. The reactor effluent for this step is a CO2 rich waste gas. The key advantages of the proposed TSSER concept over the above-described PSSER process are a elimination of the usually expensive .