Recycling device for spent caustic residues from ethylene

Abstract

The invention provides a recycling device for spent caustic residues from ethylene, and belongs to the technical field of environmental protection. Under the action of carbon dioxide, sodium sulfide is converted into a mixed solution of sodium carbonate and sodium bicarbonate, at the same time, hydrogen sulfide is generated, and air stripping is performed; a causticizing system comprises a causticizing tower, a causticizing liquid precipitation separation tank and a causticizing mud storage tank, calcium hydroxide reacts with sodium carbonate to generate calcium carbonate precipitation, the sodium carbonate is converted into sodium hydroxide, calcium carbonate which is generated through the reaction is dewatered and dried, and powdery lime is prepared and fed into dry-method desulfurationequipment to be recycled; a refining system comprises an adsorption refining reaction tank, a to-be-treated regenerated liquid storage tank, an anaerobic VTBR efficient reactor, an aerobiotic VTBR efficient reactor, a regenerated liquid clear water storage tank and a recovered alkali liquor storage tank, performs refining on causticizing liquid to remove a large amount of chroma and organic matter, reserves alkalinity and achieves recovery of the sodium hydroxide. The device can efficiently recycle spent caustic, effectively utilize side product in the whole process, and achieve zero dischargeof spent caustic and waste.

Description

technical field [0001] The invention relates to a device for recycling waste ethylene slag, which belongs to the technical field of environmental protection. Background technique [0002] In the production process of petrochemical enterprises, NaOH solution is often used to absorb H 2 S and alkali washing oil products, a large amount of waste lye is produced, mainly including waste lye containing inorganic sulfur produced by catalytic cracking, hydrofining, and ethylene production, waste lye containing organic sulfur produced by condensate oil processing, and diesel oil, lubrication Sodium naphthenate-containing waste lye produced in the process of oil alkali washing and refining. Petrochemical alkali washing waste liquid contains different concentrations of free alkali, neutral oil and naphthenic acid, and also contains a large amount of sodium sulfide, which has the characteristics of deep color, stench and strong corrosion, and is included in the "National List of Danger...

AI Technical Summary

Problems solved by technology

[0003] At present, the main problems in the treatment process of alkali washing wastewater in petrochemical enterprises are that hydrogen sulfide produced by the reaction of sulfide is easy to escape when neutralization method is used, causing environmental pollution and poisoning incidents of operators; wet oxidation method is relatively mature, but Treatment under high temperature and high pressure has high requirements on equipment materials and large investment; biological treatment needs to be diluted with water, and the discharge cannot meet the standard, which affects the normal operation of the sewage plant; the existing technology does not treat high-concentration naphthenic acid, Recycling of phenol, sodium hydroxide and sodium carbonate, etc., resulting in waste of resources, and at the same time, a large amount of concentrated brine is produced, which increases the difficulty of subsequent sewage treatment

Images