A process and device for deep recovery and treatment of synthetic leather wastewater

Abstract

The invention relates to advanced recycling treatment process and device for waste water generated from synthetic leather production. The advanced recycling treatment process includes the steps of subjecting clear liquid obtained by filtering waste water generated from synthetic leather production to heat exchange with vapor concentrate; partially dehydrating the waste water; subjecting vapor generated from a dehydration and distillation system to dehydration and distillation and then taking the vapor as a heating source for a second reboiler; feeding high-concentration waste water produced from a first reboiler into vaporization system to vaporize and then feeding the vapor into a refine distillation system; pressing distillation residues and filter residues in a pressing system to obtain liquid, returning the liquid obtained by pressing to a filtering system, feeding and drying solid residues in a drying system and then recycling DMF of the residues, feeding gas generated by drying into the refine distillation system and then purifying the gas, and burning or recycling solid residues obtained by drying; feeding the high-concentration waste water from the vaporization system into the refine distillation system, feeding vapor generated by means of distillation and separation into a condensation system and then condensing the vapor, and discharging the high-purity DMF obtained by distillation from the second reboiler. Thus, advanced recycling and utilizing of DMF-containing waste water is achieved.

Description

technical field [0001] The invention relates to a process and device for deep recovery and treatment of synthetic leather wastewater, belonging to the field of resource utilization of chemical wastewater. Background technique [0002] Dimethylformamide is a colorless transparent liquid at normal temperature and pressure. It is widely used as a solvent in the production of wet-process polyurethane synthetic leather. A large amount of DMF wastewater will be generated in the production of synthetic leather. DMF has low toxicity to the human body and can be inhaled in high concentrations. DMF can cause acute poisoning. Therefore, recycling DMF wastewater can not only reduce environmental pollution and environmental protection pressure, but also reduce production costs. [0003] At present, the recovery process of DMF wastewater mainly adopts a rectification tower to separate and recover DMF, but the rectification process consumes a lot of energy, the rectification time is long,...

AI Technical Summary

Problems solved by technology

Patents CN200510061857.5 and CN201310304564.X disclose a method for the recovery of DMF-containing wastewater by multi-effect distillation. Although these methods can save the recovery energy consumption of DMF wastewater, they only consider the recovery of DMF in wastewater, and do not consider the recovery of DMF. Deep Recovery of Distillation Residue

In addition, there are many equipments in multi-effect distillation, the residence time of materials in the equipment is long, and the possibility of DMF decomposition is increased; the process is complicated, and the overall process is difficult to operate and control; the temperature difference between each effect distillation tower is small, so that the heat transfer equipment needs more Large heat transfer area, large investment in equipment

Patent CN201310001454.6 discloses a synthetic leather DMF recovery residue treatment process and system, which uses an evaporator to recover DMF in the residue, but the high-viscosity residue in the evaporator cannot be heated evenly by a single agitator, and its heat transfer effect is as good as drying. The effect is far less than that of a rake dryer; and the distillation residue is directly evaporated, which contains a lot of water, and the energy consumption of the residue recovery process is high

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