(98d) Decentralized Production of Hydrogen for Residential PEM Fuel Cells From Piped Natural Gas by Low Temperature Steam-Methane Reforming Using Sorption Enhanced Reaction Concept
AIChE Spring Meeting and Global Congress on Process Safety
2011
2011 Spring Meeting & 7th Global Congress on Process Safety
Advanced Fossil Energy Utilization
Fuel Processing for Hydrogen Production (I)
Wednesday, March 16, 2011 - 9:10am to 9:30am
Decentralized residential power generation employing a H2 PEM fuel cell requires that essentially CO free H2 be produced on site by catalytic steam reforming of piped natural gas and then purifying the product H2 (removal of bulk CO2 and dilute or trace CO impurities). Currently, it may be achieved by subjecting the reformed gas to water gas shift reaction followed by (a) removal of all COx impurities by a PSA process or (b) selective oxidation in a catalytic PROX reactor to reduce only the CO impurity below ~ 10 ppm for use in the fuel cell. The latter approach assumes that the detrimental effect of CO2 on the performance of the fuel cell is negligible - an assumption which may not be valid.
A recently developed thermal swing sorption enhanced reaction (TSSER) process scheme can be used to combine natural gas reformation, shifting, and purification of reaction products in a compact, single unit operation for direct production of fuel-cell grade H2. The process circumvents the thermodynamic limitations (H2 conversion and purity) of the SMR reaction and allows direct production of fuel cell grade H2 with high recovery, while carrying out the SMR reaction at a much lower temperature (~ 590 C) than that required by a conventional reformation process (~850 C). The concept uses an admixture of a reversible CO2 chemisorbent (potassium carbonate promoted hydrotalcite) and a SMR catalyst in a packed-bed sorber- reactor which is periodically regenerated by using the principles of thermal swing chemisorption using super-heated steam as a purge gas.
The CO2 sorption and desorption characteristics of the chemisorbent are reviewed and simulated performance of the TSSER process for supplying H2 to a 250 KW fuel cell unit is described. A first pass process design and cost are reported.
Checkout
This paper has an Extended Abstract file available; you must purchase the conference proceedings to access it.
Do you already own this?
Log In for instructions on accessing this content.
Pricing
Individuals
AIChE Pro Members | $150.00 |
AIChE Graduate Student Members | Free |
AIChE Undergraduate Student Members | Free |
AIChE Explorer Members | $225.00 |
Non-Members | $225.00 |