Abstract:

The regeneration process of traditional LPG mercaptan removal lye discharge a large amount of waste gas and caustic sludge. The waste gas has a foul smell and contains a large amount of VOCs(volatile organic compounds). The caustic sludge contains muti-types of sulfurous salts and refractory high COD(chemical oxygen demand) components, which puts great pressure on environmental protection treatment. From the perspective of clean production, the safety & green LPG deep mercaptan removal technology uses a new mercaptan removal solvent to remove mercaptan from LPG, and then uses the poor oxygen, hydrocarbon containing and nitrogen containing desulfurized alcohol tail gas as the circulating gas, and uses oxygen(or oxygen rich) instead of air as the oxygen source for oxidation reaction to oxidize and regenerate the mercaptan removal solvent, and uses gasoline extraction to remove the generated disulfide. A certain set of liquefied petroleum gas sweetening unit has been renovated using this technology. The stable operation results of 18 months show that the total sulfur of liquefied petroleum gas is stably controlled below 30 mg/m³, and the mercaptan sulfur is controlled at around 10 mg/m³. At the same time, zero emission of exhaust gas and zero discharge of purged caustic to water are achieved, reducing the discharge of inorganic salts into water by about 200 TPY and VOCs emissions by 8.15 TPY.

Key words:

摘要：

传统液化石油气脱硫醇碱液再生的过程中会排放大量废气和碱渣，废气有恶臭气味，含有大量VOCs(挥发性有机物),碱渣含有大量含硫盐类和难降解高COD(化学需氧量)组分，环保处理难度大。安全环保型液化石油气深度脱硫醇技术从清洁生产角度出发，采用一种新型脱硫醇溶剂脱除液化石油气中的硫醇，然后以贫氧、含烃、含氮的脱硫醇尾气作为循环气，用氧气(或富氧气)代替空气作为氧化反应的氧源，对脱硫醇溶剂进行氧化再生，同时使用汽油抽提带走产生的二硫化物。某套液化石油气脱硫醇装置应用该技术完成改造，18个月的平稳运行结果表明，液化石油气总硫稳定控制在30 mg/m³以下，硫醇硫质量浓度控制在10 mg/m³左右，同时实现了废气和碱渣水体零排放，减少VOCs排放8.15 t/a,减少向水体排放无机盐约200 t/a。

关键词: 安全环保型, 液化石油气, 深度脱硫醇, 废气零排放, 碱渣水体零排放, 在线再生, 效益核算