Abstract:

The hydrogen production unit with 100 000 m³/h hydrocarbon steam conversion and pressure swing adsorption(PSA) is investigated as research subject. The composition and properties of the conversion gas, desorption gas and flue gas are analyzed. It is found that the removal carbon dioxide from flue gas is not economical. Carbon dioxide is suitable for removal from conversion gas and desorption gas. Meanwhile, the effect of conversion gas decarbonization on PSA is also investigated. The result indicates that the hydrogen recovery rate of PSA is increased by 1 percentage point and the feedstock consumption is reduced by 1% when conversion gas is 100% decarburized for the existing units. As for the new units, the hydrogen recovery rate can be increased by 2 percentage points. The energy consumption and capitalized cost between the processes of conversion gas decarbonization with N-methyldiethanolamine(MDEA), desorption gas decarbonization with MDEA and VPSA is compared. The results show that the energy consumption and capitalized cost between desorption gas decarbonization with VPSA and conversion gas decarbonization with MDEA are low, and the desorption gas decarbonization with VPSA method for existing units has more advantages. For new units, the conversion gas decarbonization with MDEA is recommended. Simultaneously, the influence of CO₂ removal on the existing units, especially the reforming furnace, is analyzed, and some recommendations are made for accounting and evaluating the related equipment of the reforming furnace to ensure the safe and stable operation of the unit in a long period.

Key words: natural gas hydrogen production unit, carbon dioxide recovery, conversion gas, desorption gas, reformer flue gas, MDEA method, VPSA method

摘要：

以100 dam³/h烃类蒸汽转化+变压吸附(PSA)氢提纯制氢装置为研究对象，分析了变换气、解吸气、烟气的组成及性质，得出：从烟气中脱除二氧化碳经济性差；二氧化碳适合从变换气和解吸气中脱除。研究了变换气脱碳后对PSA的影响，得出：变换气脱碳率为100%时，现有装置的PSA氢气回收率提高了1百分点、原料消耗量降低了1%,新建装置的氢气回收率提高了2百分点。对变换气N-甲基二乙醇胺(MDEA)脱碳、解吸气MDEA脱碳、解吸气VPSA(真空变压吸附)脱碳3种方案的能耗和投资进行比较，结果表明：解吸气VPSA脱碳和变换气MDEA脱碳能耗低，投资少。对于现有装置脱碳改造，解吸气VPSA法更有优势；对于新建装置，推荐选择变换气MDEA脱碳。同时分析了脱除二氧化碳后对现有装置特别是转化炉的影响，提出了对转化炉相关设备进行核算和评估的建议，以确保装置长周期安全平稳运行。

关键词: 天然气制氢装置, 二氧化碳回收, 变换气, 解吸气, 转化炉烟气, MDEA法, VPSA法