High-purity H2 production with CO2 capture based on coal gasification

Abstract

A novel hybrid concept is proposed, combining Pd-alloy membrane and low temperature separation technology, to produce pure H2 from gasified coal and capture the main part of the generated CO2. 75% of the H2 produced from gasification and water-gas shift is separated from the shifted syngas through H2-selective Pd-alloy membranes. After water removal, the H2-depleted, CO2-rich retentate stream is compressed and cooled, after which CO2 is condensed out at a purity level of ~99%. The "waste" volatiles from the low-temperature CO2 separation constitute a low heating value syngas that is burnt in a gas turbine. The gas turbine with a steam bottoming cycle generates a surplus of electricity that could be employed for H2 liquefaction. Altogether, the concept has the potential to be developed into a stand-alone high-purity H2 production unit with CO2 capture, suitable e.g. for remote areas from where H2 and possibly also CO2 must be transported by ship. However, the investigations of three different process alternatives, as well as three membrane separator parameters, illustrate that there are many degrees of freedom in the proposed concept that require further analysis, both individually and how they interact, in order to establish an optimized and purposeful stand-alone H2 production concept.

Perovskite Oxide Based Electrodes for High‐Performance Photoelectrochemical Water Splitting

“…[1] Nowadays,H 2 can be produced directly through several routes such as steam reforming/partial oxidation of hydrocarbons,c oal gasification, and water splitting. [2][3][4][5] Among these technologies,water splitting has attracted rapidly increasing attention due to the high abundance of water (covering % 71 %o fthe Earths surface), the high purity of H 2 as generated through water splitting,n or equirement of high temperature,a nd great reduction in CO 2 emissions. [6][7][8][9] Among the various water splitting systems,s olar energybased water splitting devices have attracted growing attention due to the fact that solar energy is considered as the most abundant energy source since approximately 36000 TW of the solar energy can reach the land each year.More specifically,if 0.1 %ofthe sunlight energy reaching the land per year can be effectively utilized, it is sufficient to meet the predicted annual energy consumption required in 2050.…”

“…Hydrogen gas (H 2 ), which has a higher gravimetric energy density than gasoline (120 vs. 44 MJ kg −1 ), no carbon emission, and renewable and storable nature, is considered as an advanced energy carrier to substitute traditional fossil fuels . Nowadays, H 2 can be produced directly through several routes such as steam reforming/partial oxidation of hydrocarbons, coal gasification, and water splitting . Among these technologies, water splitting has attracted rapidly increasing attention due to the high abundance of water (covering ≈71 % of the Earth's surface), the high purity of H 2 as generated through water splitting, no requirement of high temperature, and great reduction in CO 2 emissions …”

Hydrogen Production Technologies Overview

“…The integrations of the coal gasification with other systems have been studied by different researches [239]- [249]. Thermodynamic evaluations using the first and second law of thermodynamics have been conducted on the integrated gasification systems in their analyses [242]- [250].…”

The Related Study Tendencies in the Field of Gasification: A Bibliometric Approach

“…As a result, the electricity is produced [40][41][42][43]. Hydrogen can also be produced with integrated systems that are applied to coal gasification systems [44][45][46][47][48][49][50]. Additionally, synthetic fuels can be produced [51][52][53][54][55][56][57].…”