Steel slag-enhanced reforming process for blue hydrogen production from coke oven gas: Techno-economic evaluation

Abstract

Sorption-enhanced reforming is a low-cost and promising blue hydrogen production technology with intrinsic carbon capture. With the widespread recognition of hydrogen energy as an energy carrier, the demand for hydrogen is anticipated to expand quickly. Combining this technology with chemical looping concept to achieve autothermal operation has recently sparked considerable interest, with sorbent-oxygen carrier composites serving as both an essential ingredient and a major cost driver. In this work, a steel slag-enhanced reforming processes for blue hydrogen production from coke oven gas is examined, addressing a thorough analysis on operational parameters and economic competitiveness. The reforming reactor outperformed at a steel slag/coke oven gas molar ratio of 1.0 and a temperature of 600 °C. In this case, 1 mole of coke oven gas can theoretically be converted to 1.7 moles of hydrogen with a purity of nearly 99% without the necessity of further separation equipment. Additionally, the CO2 capture efficiency exceeds 98%. The reacted steel slag is regenerated in air and calcination reactors and is primarily composed of Ca2SiO4, CaFe2O4, CaO and Ca3(PO4)2. In terms of economic competitiveness, the proposed process necessitates a higher total capital investment while requiring a lower total production cost than the most often utilized PSA technology. Of all the contributing factors, the price of hydrogen has the most significant impact. When it falls by 20% from present level, the payback period lengthens considerably, rendering the project unprofitable. Despite this, growing carbon prices and hydrogen demand in the context of carbon neutrality offer a good potential for the technology to gain widespread adoption.