PTQ Q2 2022 Issue

Achieving 95% direct CO 2 reduction for hydrogen plants Decarbonisation solutions targeting existing refinery hydrogen plants enable refiners to achieve long-termCO 2 capturewhileminimising site space requirements and capital

KEN CHLAPIK, DOMINIC WINCH and DIANE DIERKING Johnson Matthey

B ased on decades of reforming experience, solutions using Advanced Reforming technol- ogies can be integrated into exist- ing hydrogen plants for 95% carbon dioxide (CO 2 ) reduction. 1 The syn- gas industry can reduce its CO 2 emissions using innovative solu- tions for the energy-efficient pro - duction of hydrogen, ammonia, and methanol that are demonstrated at scale and available today. Conventional, or grey, syngas production uses a steam methane reformer (SMR) to convert gasi- fied coal, natural gas, and other hydrocarbon based feedstocks into a mixture of hydrogen and carbon monoxide. The hydrogen produced via this process is used for petro- leum based clean fuel, ammonia fer- tiliser, and methanol production. The syngas carbon monoxide (CO) can be used to produce chem- icals, fuel, and energy, or additional hydrogen (H 2 ) via the water gas shift (WGS) reaction. While syngas production through the decades has focused on reducing production cost, attention is now on reducing green - house gas (GHG) emissions to meet 2050 net-zero CO 2 emissions targets. Broadening the use of proven Advanced Reforming technologies, as well as CO 2 capture, utilisation, or storage technologies (CCUS), can significantly reduce the car - bon intensity of syngas produc- tion. These CCUS technologies use existing technology and materials, manufacturing, and supply chain infrastructure, enabling these solu- tions to be utilised at scale today. Valued assets Fifty years ago, most of the hydro-

SMR through off-gas recycling. The plants’ recycled stream, or PSA purge gas, is the predominant por- tion of the fuel to the SMR. While there might be long-term refinery site or regional plans to introduce low carbon hydro- gen-fuelled energy through new blue or even green hydrogen assets to meet 2050 net-zero CO 2 emissions targets, many existing hydrogen plants (see Figure 1 ) will be revamped to address the larg- est single source of CO 2 emissions within the refinery. CO 2 in SMR based H 2 production Conventional SMR technology comprises a fired heater with cat - alyst filled tubes, in which reform - ing reactions take place. Usually, gasified coal, natural gas, or other hydrocarbon based fuels, such as refinery off-gas and PSA purge gas, are burned with air in the fired heater to generate thermal energy required for the reforming reactions. CO 2 generated in the fuel side of the SMR is emitted in the flue gas stream and referred to as post-combustion CO 2 . In general, the post-combustion flue gas is produced at low pressure and con- tains water, excess oxygen, and significant quantities of combus - tion related impurities from the fuel and air. Although technically complex, established solvent based technologies can be used to capture post-combustion CO 2 . The other source of CO 2 orig- inates from process-side syngas production, where natural gas is converted into a mixture primarily of H 2 , CO 2 , and CO. This syngas is

43% 0-20 years old

57% > 20 years old

gen available on a refinery site was a byproduct stream from the catalytic reformer. As clean fuel legislation progressed around the globe, SMR based hydrogen plants have been the means to produce the additional hydrogen needed to manufacture these clean fuels, pro- viding ultra-low sulphur fuels that improve the environment in our cit- ies and regions. There are more than 700 refinery hydrogen plants around the world, and nearly 90% of these plants are SMR based. Over 40% are less than 20 years old, with many still being depreciated. These more mod- ern plants have been designed to improve the efficiency and cost of the hydrogen produced, as well as manage the capital cost of the hydrogen plant. For the last 30 years, most of these plants have been designed with pressure swing adsorption (PSA) based hydrogen purifica - tion systems that reduce the addi- tional fossil fuel demand for the Figure 1 Global refinery hydrogen plant age distribution (based on JM historic database)

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