Decarbonisation Technology - February 2022 Issue

Electricity

Syngas

Gasier

Electricity

Oxygen

Coal

Cooling & cleaning

Condenser

Water

Slag

Exhaust gas

Pure oxygen from an air separation unit is required for coal, petcoke or heavy refinery residue gasification to produce hydrogen-rich syngas

Purple hydrogen – coal gasification with CCS The Hydrogen Energy Supply Chain (HESC) project in Australia will demonstrate the viability of ocean shipments of liquid hydrogen from Australia to Japan. It will open the door to full scale energy exports of low-carbon hydrogen. At this early stage of the project, hydrogen gas is produced from the gasification of brown-coal at a pilot plant in the Latrobe Valley in the Australian state of Victoria. Gasification involves reacting coal with oxygen at a high temperature to produce syngas which contains CO 2 , carbon monoxide, and hydrogen. This gas mixture is further purified to yield the desired hydrogen. The result is a high purity, low- cost hydrogen gas which can be cryogenically cooled to form liquid hydrogen for efficient long- distance transportation. The ‘brown’ hydrogen produced in this gasification process is generated from coal and for every tonne of hydrogen produced on this pilot reactor 12 tonnes of CO 2 are generated. When the HESC pilot project is complete, a full- scale gasification plant incorporating CCS will be used to make the hydrogen production process more sustainable. Hydrogen produced from coal combined with CCS is sometimes referred to as ‘purple’ hydrogen. Permanent underground CO 2 storage will be integrated with the CarbonNet CCS scheme. It aims to establish a commercial-scale CCS network in Victoria, Australia. The network will

turbines which produce 2.4 GW of electricity in an integrated gasification combined cycle, or IGCC power plant. The syngas-island will also export hydrogen and steam to the refinery. To feed the hungry gasifiers at Jazan, the process requires six Giga-scale ASUs supplied by Air Products, each one rated at 3,000 tonnes per day of oxygen. Coal or petcoke gasification is a robust technology that can cope with oxygen at about 95% purity and the ASUs that feed gasification projects are generally optimised on this basis. The ASU can simultaneously produce nitrogen for refinery purging and inerting processes at a purity close to 99.999%. Air Products has been instrumental in the Jazan refinery heavy residue gasification project and has secured their position in coal gasification through the acquisition of the GE Gasification business and Shell’s coal gasification technology. The stated goal of these deals was not to become a technology licensor rather to enable the company to leverage gasification to win the associated ASU and syngas processing contracts as an integrated part of their industrial gases portfolio. The Lu’an coal to chemicals project at Changzhi in China’s Shanxi province, is one of the Giga- scale coal gasification investments that Air Products has made. Four gasification reactors have been constructed to supply syngas to the chemicals complex.