High-salinity wastewater treatment method of epoxypropane/styrene co-production device

Abstract

The invention discloses a high-salinity wastewater treatment method of epoxypropane / styrene co-production device. The method adopts a novel process scheme featuring incineration, waste heat boiler andsoda slag comprehensive utilization. The method mainly comprises the steps including liquid waste incineration; denitration treatment; cooling regulating; waste heat recovering; dedusting treatment;and soda slag recycling. According to the method, high-temperature flue gas entering a waste heat boiler is cooled firstly, molten inorganic salt can be precipitated in the solid form and is preventedfrom entering the waste heat boiler, then high-temperature flue gas enters the waste heat boiler to produce steam of the required grade as a by-product, soda slag produced by a system can be collected from the bottom of a vertical incinerator, the lower portion of the waste heat boiler and the interior of a dust remover, is pretreated and is then used for wet method alkali washing desulfurizationfacility comprehensive utilization, and accordingly, the purposes of treatment of wastes with processes of wastes against one another, energy-saving, cost-reducing and turning waste into valuable areachieved.

Description

technical field [0001] The invention belongs to the technical field of high-salt waste water treatment, and in particular relates to a high-salt waste liquid treatment method of a propylene oxide / styrene cogeneration device. Background technique [0002] The wastewater from the propylene oxide / styrene cogeneration unit (referred to as PO / SM unit) mainly comes from the water washing and alkali washing sections of ethylbenzene peroxidation, propylene epoxidation, phenylethyl alcohol dehydration and other units. It has large water volume, high COD, It is characterized by many benzene series and high salt content. Based on the PO output of 25t / h, the waste water volume is about 32~40t / h, CODcr is about 180000~200000mg / L, and the sodium salt content can reach more than 5%wt (mainly sodium benzoate, sodium acetate, sodium phenate, etc.), which is difficult to Direct treatment by conventional biochemical treatment processes. At present, the main treatment processes for high-salt ...

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Problems solved by technology

[0004] The current submerged quenching incineration process used in the treatment of high-salt wastewater in PO / SM units mainly has the following shortcomings: (1) The high-temperature flue gas in the incinerator directly enters the quenching box for cooling, basically no recovery of heat, high energy consumption and no by-products (2) There is easy sediment in the quench tank (sodium salt precipitation and slag produced by refractory lining peeling off), usually the furnace needs to be shut down for cleaning every 3 to 6 months, resulting in a short continuous operation period of the system; (3) The flue gas is cooled by the water in the quench box, and finally discharged into the atmosphere in the form of water vapor, consuming a large amount of industrial water; (4) NO in the flue gas X The content is high, it is difficult to use SNCR denitrification, and the use of SCR denitrification requires reheating the flue gas, which is economical; (5) Since the outlet temperature of the flue gas in the quenching process is only about 90 ° C, if the S content in the flue gas is high, it is easy to produce dew point corrosion Problem; In addition, water vapor is saturated in the flue gas, and "white smoke" is emitted from the chimney outlet, and the visual effect is poor; (6) Usually, the quench incinerator is designed with positive pressure, which does not meet the requirements of GB18484; if the design is negative pressure, it needs Add larger induced draft fans, increase project investment and energy consumption; (7) Since 2016, the "National Hazardous Waste List" has included the heavy waste produced in the process of co-oxidation of ethylbenzene and propylene (ie PO / SM process) to produce styrene The distillate is listed as 261-106-11 toxic and hazardous waste PO / SM in HW11

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