Residual oil catalytic thermal cracking and coal-to-olefin waste alkali liquor resource utilization device

Abstract

The invention discloses a residual oil catalytic thermal cracking and coal-to-olefin waste alkali liquor resource utilization device which comprises a waste alkali liquor oil removal section, an oxidation section, an organic matter removal section, a causticizing section, an evaporation and concentration section, a carnallite removal section, a sodium thiosulfate recovery section and a liquid alkali preparation and recovery section. Waste lye of a DCC device and an MTO device is subjected to oil-water separation in a waste lye oil removal section, sodium sulfide contained in the waste lye is converted into sodium thiosulfate in the oxidation section, organic substances are removed through adsorption of activated carbon in the organic matter removal section, and sodium carbonate contained in the waste lye is converted into calcium carbonate and sodium hydroxide by adding quick lime in the causticizing section. Water and residual sodium sulfide, sodium carbonate, sodium chloride and sodium sulfate are further removed in the evaporation concentration section and the carnallite removal section, sodium thiosulfate is separated in the sodium thiosulfate recovery section and the liquid caustic soda preparation and recovery section, and the concentration of sodium hydroxide is adjusted. According to the method, efficient and low-cost resource utilization of the mixed salt in the waste alkali liquid is realized.

Description

technical field [0001] The invention relates to the recovery and utilization of waste lye in large-scale coal chemical and petrochemical enterprises, in particular to the resource utilization of residue oil catalytic thermal cracking and coal-to-olefin waste lye mixed salt. Background technique [0002] Large-scale coal oil and gas resources comprehensive utilization projects will produce a large amount of waste caustic sour gas in the process of alkali washing acid gas, and the devices that generate acid gas are mainly residue catalytic thermal cracking (DCC) devices and methanol-to-olefins (MTO) devices. DCC The device is taken as an example, the mixed salt content in the waste lye discharged is about 10%, and the inorganic salt components in the mixed salt are mainly sodium carbonate, sodium sulfide, sodium chloride, sodium thiosulfate and a small amount of sodium sulfate, and also contain A small amount of sodium hydroxide. At present, the treatment of this kind of wast...

AI Technical Summary

Problems solved by technology

But there are problems: ① For the process that mainly treats the waste caustic soda discharged from the DCC unit, the physical properties of sodium thiosulfate in the waste caustic will cause a large amount of extremely high salt content and viscous hydrochloric acid to be produced during steam heating mother liquor, so that the effective removal and resource utilization of sulfide and sodium thiosulfate cannot be realized; ② only the removal of carbonate is realized, which intensifies the formation of hazardous waste, and it is difficult to realize the resource utilization of carbonate ; ③ A small amount of inorganic salts will be continuously concentrated in the process of recycling, and the produced water cannot be continuously recycled for a long period of time

Images