Energy-saving two-stage forward osmosis coupled two-effect membrane distillation wastewater high-concentration treatment system

Abstract

The invention discloses an energy-saving two-stage forward osmosis coupled two-effect membrane distillation wastewater high-concentration treatment system which comprises a first-stage forward osmosis membrane assembly, a second-stage forward osmosis membrane assembly, a first-effect membrane distillation assembly and a second-effect membrane distillation assembly; and a heat exchanger, a pump, a condenser and an evaporator. The draw solution is concentrated to a near-saturation state through the membrane distillation assembly, higher osmotic pressure is provided for forward osmosis, the concentration ratio of salt-containing wastewater is higher, the forward osmosis process is coupled with the membrane distillation process, and the concentration efficiency is higher. The heat recovery system (composed of the condenser, the evaporator, the compressor, the throttling valve and the like) is added to recycle energy, so that energy circulation of the system is achieved, the total energy consumption of the system is reduced, and energy is saved. According to the two-effect membrane distillation, the draw solution is concentrated through evaporation, steam obtained through evaporation is condensed to form fresh water, and the high water production quality is achieved. The system is free of high-pressure working conditions, low in equipment mechanical strength requirement, easy and convenient to operate, environmentally friendly and low in cost.

Description

technical field [0001] The invention belongs to the technical field of wastewater treatment, and in particular relates to an energy-saving two-stage forward osmosis coupled two-effect membrane distillation wastewater high-concentration treatment system. Background technique [0002] At present, with the rapid development of economy and society, the discharge of saline wastewater in industrial production is increasing. These saline wastewater also contain a large amount of organic matter. Direct discharge will cause serious damage to the ecological environment. Therefore, the treatment of saline wastewater has become an urgent industrial problem to be solved. [0003] There are many technical methods currently available for the treatment of saline wastewater, mainly including chemical methods, physical methods, and biological methods. The chemical method generally adopts measures such as adding chemical agents to adjust the acidity and alkalinity, carrying out chemical react...

AI Technical Summary

Problems solved by technology

At present, the simple coupling of single-stage forward osmosis and single-effect membrane distillation is commonly used in the treatment of saline wastewater. Although this method can also reduce energy consumption and regenerate the draw solution, the energy-saving efficiency and concentration efficiency need to be further improved.

Images