Forward osmosis sea water desalination system

Abstract

The invention discloses a forward osmosis sea water desalination system which comprises a forward osmosis device, a hydraulic turbine, a speed increaser, a pressure transducer, a heat pump system, a turbine generator and an absorption tower. According to the forward osmosis sea water desalination system, a drawing solution absorbs water molecules through the forwards osmosis device and obtains osmosis energy, and redundant osmosis energy is output through the hydraulic turbine to drive the heat pump system to work. A solute of the drawing solution volatilizes steam or is thermally decomposed into a gas after absorbing heat in a condenser of the heat pump system, and drives the turbine generator to generate electricity. A fresh water solution obtained after separation of the drawing solution releases heat in an evaporator of the heat pump system to form cooling water, one part of cooling water enters an absorbing tower for spraying, and absorbing steam and gas to re-generate a concentrated drawing solution, and the other part of cooling water is output as product water. The forward osmosis sea water desalination system has the characteristics of high osmosis energy utilization rate, low energy consumption of a device, wide application range and the like, is greatly promoted in an application progress of a forward osmosis technology in the field of sea water desalination, and is wide in application prospect in the future development.

Description

technical field [0001] The invention belongs to the technical field of seawater or brackish water desalination, in particular to a forward osmosis seawater desalination system. Background technique [0002] Desalination of seawater or brackish water is an effective strategic approach to solve the shortage of freshwater resources. How to achieve water purification and desalination at low cost is an important scientific and technological issue that people are concerned about. At present, seawater desalination methods are mainly thermal methods (multi-effect evaporation, multi-stage flash evaporation, pressure steam distillation) and membrane methods (reverse osmosis, electrodialysis). Since thermal desalination is a phase change process, generally heating is required, and the energy consumption is relatively high, while the process of reverse osmosis is simple and the energy consumption is low, so reverse osmosis has been developed rapidly and widely used in recent years. Alt...

AI Technical Summary

Problems solved by technology

This technology realizes the separation of product water and the recycling of solutes through the method of thermal volatilization and condensation, but there are still the following disadvantages: First, it needs to be driven by external heat, and the application range is limited. In addition, it involves coupling with the heating system. It is easy to cause problems such as increased investment and increased operating costs. Second, the external heat source is generally renewable energy or low-grade heat energy, and the energy utilization rate is not high. In addition, the heat recovery rate of the low-temperature waste heat of the product water is low, which will inevitably lead to energy consumption of the entire system. The higher problem seriously weakens the advantage of low energy consumption of the principle of forward osmosis seawater desalination, so that forward osmosis technology has no energy-saving advantages compared with reverse osmosis technology or thermal distillation technology

Therefore, the technology is not yet mature, and the energy system of the draw solution still needs to be further optimized to obtain significant economic benefits.

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