Vent gas
Pretreatment unit
CO capture unit
Cooler
Cooling water
Wash
Pump
Condenser
Cooler
Make-up
Cooler
Pump
Direct contact cooler
Absorber
Stripper
Steam
Blow-down
Lean/rich heat exchanger
Pump
Flue gas after ue gas desulphurisation
Reboiler
Rich solvent pump
Lean solvent pump
Courtesy of Emerson Automation Solutions
Figure 3 Typical configuration of a CO 2 capture process
age, resiliency, and emissions reduc- tions. H 2 produced from renewable or other resources can be injected into natural gas pipelines, and con- ventional end users of natural gas can then use the blend to generate. There is increasing investor inter- est to use H 2 for power genera- tion, marine transport, and other applications. This explains why LNG exporters are considering H 2 options for their clients based on LNG and port infrastructure repur- posed for waterborne liquid H 2 shipment. For example, with some ‘tweaks’, single mixed refrigerant modular liquefaction technology can be used to liquefy H 2 . Cryogenic technology that sub- cools natural gas to LNG could also cool volatile H 2 gas down to -253°C to create liquefied H 2 , increasing its density. The real challenge may be the ability of pipeline infrastructure to avoid H 2 embrittlement, com - promising safety. As far as the end user is concerned, liquid H 2 ’s high energy density may also be one of the best decarbonisation options for marine shipping. Modifications From phase separators and sub coolers to refuelling and bunkering facilities, natural gas to LNG cryo-
Interest in green and blue H 2 is rapidly expanding. In any case, the cost to increase H 2 production from sources outside conventional H 2 production technologies (SMR, ATR) remains high. Technical chal- lenges still need to be overcome. For example, membrane based electro- lysers cannot output H 2 at pressures required for refinery hydrotreating and hydrocracking of biofeedstocks. This is due to a number of fac- tors, including the sensitivity of most electrolysers’ membranes to high pressures over 70 bar (1015 psi). As a result of these high-pres- sure requirements, expensive and maintenance-intensive compressors are required to be co-located with almost all electrolysers, increas- ing the true cost and complexity of clean H 2 . One company, Supercritical Solutions Ltd, recently developed a new class of electrolyser. Its propri- etary membrane-less design enables it to exploit the benefits of supercrit - ical water, outputting gases at over 200 bar (2900 psi) of pressure, elim- inating expensive H 2 compressors (in most applications). The technol- ogy takes direct aim at decarbonis- ing industrial H 2 use cases. Supercritical’s electrolyser design can tolerate and exploit the bene-
genic liquefaction technology can be modified to liquefy H 2 . In addition, a new generation of cryogenic pipe- line referred to as cryogenic pipe- in-pipe (PiP) increases efficiency. With these modifications, LNG infrastructure to liquefy H 2 could be about 55% cheaper than building greenfield H 2 infrastructure. Green hydrogen H 2 is a crucial molecule for NZE decarbonisation targets. Today, the industrial H 2 market is already at $120 billion and is expected to increase. In addition integrating green H 2 ecosystems in the down- stream refinery and petrochemical industry, H 2 as a stand-alone fuel will grow in importance. Bank of America recently estimated $11 tril- lion in green H 2 investment oppor- tunities by 2050. New H 2 production sources (such as electrolysers) are under consid- eration. Coprocessing of hydro- carbon feeds with biomass based feeds requires significantly more H 2 . Hydroprocessing technologies used in the refining sector for copro - cessing require H 2 pressures of 70 to 230 bar (1015 to 3336 psi). These pressures, at least for refinery oper - ations, challenge membrane based electrolysers.
10 Gas 2022
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