关键词: 液化石油气脱硫醇装置, 抽提后汽油, 钠含量, 分离时间, 物理沉淀, 沉淀罐, 吸附过滤, 注水

Abstract: The traditional Merox process is commonly used in LPG desulfurization units. During the production process, the disulfides contained in the regenerated alkaline solvent are removed by gasoline extraction, resulting in trace amounts of alkaline substances in the extracted gasoline, which increases the sodium content and pH value of the extracted gasoline, affecting downstream production. A process technology route that can effectively reduce the sodium content in extracted gasoline was developed by adding physical settling, water washing, and adsorption filtration process procedures. The results show that: after adding two 50m³ settling tanks, the separation time of oil and alkali was extended by 22.2h, and the mass fraction of sodium in gasoline was reduced from about 400ng/g to about 200ng/g; by adding a water injection process at the inlet of the settling tank, the sodium mass fraction in gasoline was reduced to a minimum of 73ng/g during the initial use. However, long-term operation will lead to an increase in sodium content and a large amount of waste alkali emissions; by using a molecular sieve filter for filtration and sufficient settling, the sodium mass fraction in gasoline can be reduced to about 20ng/g, with a total desodium rate as high as 95%.

Key words: LPG demercaptanization unit, extracted gasoline, sodium content, separation time, physical settling, settling tanks, adsorption filtration, injecting water