Distillation seawater desalting system using expander and compressor

Abstract

The invention discloses a distillation seawater desalting system using an expander and a compressor. The distillation seawater desalting system comprises a condenser, an expander and a compressor, wherein the condenser is used for performing heat exchange to influent raw seawater and secondary vapour, and then respectively discharging the heat-exchanged pre-heated seawater and condensed water, and discharging the seawater; an evaporator is provided with a primary effect evaporator, a plurality of middle effect evaporators and tail effect evaporators, which are arranged in series in sequence, wherein the tail effect evaporators are connected with the condenser, and the primary effect evaporator is provided with an inlet of mixed vapour; the expander is connected with the primary effect evaporator of the evaporator; and the compressor is respectively connected with the middle effect evaporators or the tail effect evaporators of the evaporator and the expander, respectively. The distillation seawater desalting system can improve the utilization efficiency of the vapour, so that the energy utilization efficiency of the seawater desalting system can be improved to more than 50% from the current about 25%, thus higher water making ratio is acquired and high efficiency utilization of the energy is achieved to achieve the energy-saving and environment-friendly purpose. The distillation seawater desalting system not only can be used for desalting seawater, but also can be used for concentrating feed liquid in the industries such as chemical engineering, food, pharmacy and the like.

Description

technical field [0001] The invention relates to a distillation seawater desalination system. In particular, it relates to a distillation seawater desalination system using an expander and a compressor with steam as energy input. Background technique [0002] Low-temperature multi-effect distillation seawater desalination is one of the mainstream commercial seawater desalination technologies at present. Its process system is mainly composed of evaporator, condenser and steam jet pump (TVC), such as figure 1 As shown, the working steam is input into the heat transfer tube of the evaporator, and the steam is condensed to obtain fresh water, and at the same time, the latent heat is released to heat the seawater outside the tube to evaporate to obtain secondary steam, and the secondary steam is gradually condensed to obtain fresh water that is many times that of the input steam. In order to improve the utilization rate of steam, the traditional low-temperature multi-effect disti...

AI Technical Summary

Problems solved by technology

During the whole process, throttling, mixing and collision of steam in the steam jet pump will cause a lot of energy loss

Therefore, the energy utilization efficiency of the steam jet pump is low, only about 25%

[0005] In addition, the steam jet pump has a fixed structure and poor adjustability, and can only work within a narrow range near the design point. If the pressure of the working steam deviates from the design point, the system will be in an unstable operating state, and even cause the system to fail. water

Therefore, in the traditional low-temperature multi-effect distillation seawater desalination system, in order to adapt to the input working steam of different temperature and pressure, it is usually necessary to configure steam jet pumps of different specifications, which increases equipment investment

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