Domestic refineries have successfully applied medium-variable pressure gas decarburization hydrogen production technology for the first time

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Hydrogen is an important blending component for improving the quality of gasoline and diesel. Increasing hydrogen production capacity while reducing the energy consumption associated with its production is a common goal for oil refining companies. Currently, oil refining companies generally use the light hydrocarbon steam reforming + PSA (pressure swing adsorption) process to produce hydrogen. This process yields hydrogen with a high purity, exceeding 99.9%, but it has the drawback of a relatively low hydrogen recovery rate, typically around 85%. “The \"variable-pressure gas decarburization hydrogen production technology for dry gas hydrogen production\" involves adding a decarburization step before the variable-pressure gas enters the PSA unit; activated MDEA is used to remove the majority of the carbon dioxide present in the variable-pressure gas, thereby reducing the impurity content in the gas fed into the PSA unit and increasing the hydrogen recovery rate of the PSA process (which can generally exceed 90%). This approach retains the high purity of hydrogen produced by the PSA process. Meanwhile, the high-concentration carbon dioxide generated as a by-product can be further utilized to produce food-grade carbon dioxide or dry ice, or to treat alkaline sludge from refineries, offering broad application prospects. Furthermore, by adopting the medium-temperature shift gas decarburization process, the total amount of PSA regeneration gas is reduced and its calorific value is increased, which helps to significantly lower the energy consumption of the converter in hydrogen production plants. If high-temperature medium-temperature shift gas is used as the heat source for the reboiler at the bottom of the regeneration tower in the decarburization unit, and the air cooler for the medium-temperature shift gas in the hydrogen production plant is shut down, the decarburization unit can operate with virtually no energy consumption. The medium-pressure gas decarburization unit was completed at the Wuhan branch by the end of February 2010 and came online at the beginning of March. According to the project leader, once put into operation, this device will enable an annual increase in hydrogen production of around 1,500 tons, a reduction in gas consumption of about 1,000 tons per year, and cost savings of approximately 10 million yuan. The project leader also said that the food-grade carbon dioxide facility, funded by Boda Industrial Company (a company resulting from the restructuring of Wuhan Petrochemical), will be completed by the end of 2010. Once operational, it will help reduce carbon dioxide emissions, while simultaneously generating additional benefits for the enterprise, reducing processing losses, and improving the overall yield of products. It is reported that this technology is being used for the first time in hydrogen production units of China’s petroleum refining industry.