Hydrogen Production Integrated with Simultaneous CO₂ Sequestration on Fly Ashes from Power Plants

Abstract

Integration of chemical reactions with in situ adsorptive separation of one of the reaction products helps to improve the reactant conversion or/and product selectivity. In the steam‐methane reforming (SMR) process, despite a reversibility of employed reactions, the in situ adsorption of CO2 enables an almost total conversion of methane and produced CO, so pure hydrogen can be obtained directly from a single‐step adsorptive reactor. However, the main problem in practical application of such integrated process is a saturation of sorbent with CO2 and the need of its cyclic regeneration. A series of experiments to determine the kinetics for CO2 sorption on fly ashes were performed under operating conditions usually applied for the sorption‐enhanced SMR process and the possible CO2 uptake was estimated. The obtained results indicate that fly ashes can be utilized as an efficient and cheap sorbent for the considered hydrogen production process.

Simulation of Methane Steam Reforming Enhanced by in Situ CO2 Sorption Using K2CO3-Promoted Hydrotalcites for H2 Production

“…The combination of steam methane reforming and CO 2 adsorption in a single unit for hydrogen production leads to the system called the sorption-enhanced methane steam reforming process (SEMSRP). The advantage of this hybrid reactor is the reduction (or even elimination) of the separation processes while obtaining high yields and purities of the desired product and high conversion …”

“…The advantage of this hybrid reactor is the reduction (or even elimination) of the separation processes while obtaining high yields and purities of the desired product and high conversion. 15 For the SEMSRP, the CO 2 adsorbent quality is a crucial element governing this process performance. 16,17 Calcium oxide (CaO), 18,19 hydrotalcite (HTC), and lithium oxide 20−22 as Li 2 ZrO 3 are CO 2 adsorbents that are already used in this process.…”