CO lean ue gas
CO rich ue gas
CO lean ue gas
CO lean ue gas
CO lean ue gas
CO lean amine
20% NaOH (aq)
CO lean methanol
CO lean solvent
CO rich ue gas
CO rich ue gas
CO rich ue gas
CO lean ue gas
CO rich solvent
CO rich methanol
Na CO (aq)
CO rich amine
Amine-wash rotating disk contactor
Amine-wash with tower contactor
Methanol wash
Mineralisation
A selection of CO 2 capture processes based on absorption
because the sands and minerals used contain CO 2 , which is released during the melting and calcination processes. These mineral processing industries must live with the fact that this geogenic CO 2 is generated, even if heating from renewable electrical power or hydrogen is used to replace fossil fuel fired burners. However, there are many things that can be done to mitigate CO 2 emissions to the atmosphere. Decarbonisation may be ‘difficult’, but it will be possible. Due to the geogenic CO 2 emissions, part of the decarbonisation solution in glass making and other mineral processing industries must therefore include ‘carbon capture’. Disposal of the captured CO 2 in underground reservoirs may become an important service and new business model for the oil and gas sector. CCS schemes that they operate can become the CO 2 sink for these industrial CO 2 emitters. Refinery steam methane reformers (SMRs) consume natural gas to make hydrogen. The vast majority make grey hydrogen and emit CO 2 . In the long term, this can be mitigated with ‘green’ hydrogen production using electrolysers fed with renewable electricity or reformers fed with biogas. In the short term, retrofitting carbon capture to SMRs to make so-called ‘blue hydrogen’ will make a step change reduction to CO 2 emissions and take a big step towards carbon neutrality. SMRs are used to produce more than half of the world’s hydrogen today. ATRs are also used extensively for syngas production. They tend to operate at a slightly higher pressure and the product is richer in carbon monoxide than the gases produced on an SMR. Fine-tuning of blue hydrogen production technology will, in part, come from a detailed understanding of the energy
and chemical feedstocks required in any scheme. Both SMRs and ATRs can be combined with downstream shift reactors to optimise production of hydrogen or syngas. The H 2 H Saltend project is focused on producing hydrogen for industry, power, and ammonia. The major advantage of using an ATR would be the scale that can be achieved, with a high carbon capture rate and high energy efficiency. Operating pressure, and therefore product gas delivery pressure, is another aspect that differentiates SMRs and ATRs. The ATR can operate at a higher pressure, which is a benefit if hydrogen must be injected into a high-pressure gas pipeline for transmission to cities in Yorkshire and beyond. Turquoise hydrogen, biochar & solid carbon Turquoise hydrogen is produced by methane pyrolysis (also known as methane splitting or cracking) and is another pathway to produce low carbon hydrogen. Methane pyrolysis is endothermic, meaning that it requires heat energy to convert methane to hydrogen and solid carbon. There are different options for the heat supply. Indirect heating using burners fuelled by hydrogen or natural gas as a fuel is one option. Indirect electrical heating or direct heating with an electrical plasma are also possible. A question that arises from methane pyrolysis with hydrogen as the target is: what happens with the various forms of solid carbon that are produced? If turquoise hydrogen production becomes a mainstream pathway to hydrogen, the amount of solid carbon produced will greatly exceed demand from current applications. If carbon black becomes abundant at low cost, it
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