CN1302828C - Apparatus for heat recoverin multigrade flash desalting of sea water - Google Patents

Abstract

The heat recovery type multi-stage flash seawater desalination device includes circulating brine pipelines in the heat discharge section, several sets of interconnected flash chambers in the heat recovery section and flash chambers in the heat discharge section, and the circulating brine pipeline in the heat discharge section is flashed from the heat discharge section. The upper end of the chamber passes through, the outlet of the circulating brine pipeline in the heat discharge section is connected to the bottom end of the final flash chamber in the heat discharge section, and the steam outlet of the flash chamber in the upper heat discharge section is connected to the flash chamber in the next heat discharge section. The lower end of the steaming chamber is connected, and the flash brine at the bottom of the final flash chamber of the heat discharge section is connected with the circulating brine pipeline of the heat recovery section provided with a condenser through the upper end of the flash chamber of the heat recovery section, and the circulating brine pipeline of the heat recovery section is A brine heater is also installed on the pipeline, and the circulating brine coming out of the circulating brine pipeline in the heat recovery section is heated by the brine heater and then communicated with the lower part of the first-stage flash chamber of the heat recovery section flash chamber, and the upper stage heat recovery The steam outlet of the flash chamber of the first stage is connected with the lower end of the flash chamber of the next heat recovery stage through pipelines.

Description

Regeneration type multi-stage flash seawater desalination device

technical field

The invention belongs to the technical field of water, waste water, sewage or sludge treatment, and in particular relates to a recuperating type multi-stage flash seawater desalination device for multiple recovery and utilization of heat energy.

Background technique

The multi-stage flash seawater desalination system is to make the hot brine flow through several flash chambers in which the pressure is gradually reduced. Since the ambient pressure is lower than the saturated vapor pressure corresponding to the temperature of the hot brine, the hot brine is rapidly partially vaporized, resulting in Steam, condensed into fresh water. It has the advantages of simple and reliable equipment, easy large-scale operation, high operating flexibility, and the ability to utilize low-level heat energy and waste heat, etc., and has broad application prospects. However, in practical applications, since the latent heat released by the flash steam is all used to heat the circulating brine in the condensation pipe of the current stage, the existing multi-stage flash seawater desalination system has a relatively small water production ratio and a low concentration of flash brine at each stage. Too high a problem. If the water production ratio of the device is too small, the thermal economy of the system will be weakened; if the concentration of flash brine at each level is too high, the corrosion and scaling of the system will be aggravated, which will affect the safety of system operation.

Contents of the invention

The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art, to provide a system that can increase the water production ratio, reduce the concentration of flash brine at all levels of the system, and avoid the decrease of the water production ratio caused by the temperature change of the supplementary water. Thereby making the water production of the system more stable and reliable regenerative multi-stage flash seawater desalination device.

In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: comprising heat discharge section circulating brine pipeline, and several groups of interconnected heat recovery section flash chambers and heat discharge section flash chambers with condensing pipes and fresh water tanks. The characteristic is that the circulating brine pipeline in the heat discharge section is connected with the condenser and passes through the upper end of the flash chamber in the heat discharge section, and the outlet of the circulating brine pipeline in the heat discharge section is connected with the bottom end of the final flash chamber in the heat discharge section , and the steam outlet of the flash chamber of the upper heat discharge section is connected to the lower end of the flash chamber of the next heat discharge section through a pipeline, and the flash brine at the bottom of the flash chamber of the final stage of the heat discharge section is connected to The upper end of the flash chamber in the superheat recovery section is connected to the circulating brine pipeline in the heat recovery section with a condensing pipe. A brine heater is also installed on the pipeline of the circulating brine pipeline in the heat recovery section. The circulating brine coming out of the circulating brine pipeline in the heat recovery section passes through After the brine heater is heated, it is connected to the lower part of the first-stage flash chamber of the heat recovery section flash chamber, and the steam outlet of the upper-stage heat recovery section flash chamber is connected to the lower end of the next-stage heat recovery section flash chamber through the pipeline. connected.

Another feature of the present invention is: the outlet of the fresh water tank is also provided with a product water pump; the bottom of the final flash chamber in the heat discharge section is also provided with a brine sewage pump connected with the brine sewage pump; the heat recovery section flash chamber There is also a surface heater in the flash brine at the lower end of the flash chamber of the heat discharge section; a wire mesh defoamer is also provided at the lower end of the fresh water tank in the flash chamber of the heat recovery section and the flash chamber of the heat discharge section.

On the basis of the existing multi-stage flash seawater desalination system, the present invention introduces part of the secondary steam flashed out of the flash chambers of each stage to the next stage flash chamber to heat the flash brine, and at the same time The circulating seawater in the condenser of the power plant replaces the original seawater as the supplementary water of the system, thereby increasing the water production ratio of the system, reducing the flash brine concentration at all levels of the system, and avoiding the disadvantage of the decrease in the water production ratio due to the temperature change of the supplementary water, so that The water production of the system is more stable and reliable.

Description of drawings

Fig. 1 is a schematic diagram of the system of the present invention;

Fig. 2 is a structural schematic diagram of the flash chamber of the present invention.

Detailed ways

The structural principle and working principle of the present invention will be further described in detail below in conjunction with the accompanying drawings.

Referring to Fig. 1, 2, the present invention includes the heat discharge section circulation brine pipeline 12 that the inlet is connected with the condenser 11, the heat discharge section circulation brine pipeline 12 passes through the upper end of the heat discharge section flash chamber 2, and in the heat discharge section Condensers 3 are also respectively arranged on the circulating brine pipeline 12 in the section flash chamber 2, and the outlet of the circulating brine pipeline 12 in the heat discharge section is connected with the bottom end of the final stage flash chamber 2-1 in the heat discharge section, and the upper The steam outlet of the flash chamber 2 in the heat discharge section of the first stage is connected to the lower end of the flash chamber 2 of the next heat discharge section through a pipeline, and the flash brine at the bottom of the flash chamber 2-1 in the final stage of the heat discharge section passes through the brine circulation pump 6 It communicates with the circulating brine pipeline 13 of the heat recovery section provided with a condensation pipe 3-1 passing through the upper end of the flash chamber 1 of the heat recovery section, and is also provided with a brine at the bottom of the final flash chamber 2-1 of the heat discharge section. The brine sewage pump 5 connected to the sewage pump is also provided with a brine heater 9 on the outlet pipeline of the circulating brine pipeline 13 in the heat recovery section. The lower part of the first-stage flash chamber of the recovery section flash chamber 1 is connected, and a surface heater 7 is also arranged in the flash brine at the lower end of the heat recovery section flash chamber 1 and the heat discharge section flash chamber 2, and the upper one The steam outlet of the flash chamber 1 of the first-stage heat recovery section is connected to the lower end of the flash chamber of the next heat recovery section through a pipeline, and there are also set in the flash chamber 1 of each heat recovery section and the flash chamber 2 of the heat discharge section There is a fresh water tank 10 communicated with the product water pump 4, and a wire mesh demister 8 is also arranged at the lower end of the fresh water tank 10.

In the flash chamber 2 of the heat discharge section, the circulating seawater of the condenser 11 of the heat supply unit first passes through the circulating brine pipeline 12 of the heat discharge section through the condenser pipe 3 to condense a part of the flash steam generated in the flash chamber 2 of the heat discharge section, At the same time, the circulating seawater is heated, and another part of the flash steam in the flash chamber 2 of the heat discharge section is led to the flash chamber 2 of the next heat discharge section to exchange heat with the surface heater 7 to heat the flash brine and condense it. Fresh water for the product. Part of the seawater coming out of the flash chamber 2 in the heat discharge section returns to the sea, and the other part is mixed with the flash brine in the final flash chamber 2-1 of the heat discharge section after adding acid and antifoaming agent, and passed through the brine circulation pump 6 It is fed into the circulating brine pipeline 13 of the heat recovery section through the flash chamber 1 of the heat recovery section, and sequentially condenses part of the steam flashed out of the flash chamber 1 of each heat recovery section. Similarly, another part of the flash steam is led to the lower The primary flash chamber is used to heat the flash brine. After the circulating brine recovers part of the heat of the flash steam, it enters the brine heater 9 and is further heated to reach the maximum temperature required by the process, and then enters the lower part of the first-stage flash chamber in the heat recovery section, because its temperature is higher than that of the first-stage At the saturation temperature corresponding to the vacuum in the flash chamber, the flash brine begins to flash, and the flash steam goes upward through the wire mesh demister 8 to remove brine droplets and foam, and then enters the condensation zone to condense into product fresh water. Repeat the above process step by step to the last stage, a part of the flash salt water is discharged by the salt water sewage pump 5, and the product fresh water is sent into the product water tank by the product water pump 4.

In the present invention, part of the secondary steam flashed out of the flash chambers of each level is led to the next level of flash chambers to heat flash brine. According to the principle of conservation of mass, momentum and energy, the water production ratio of the device is significantly increased. big.

Claims (5)

1, apparatus for heat recoverin multigrade flash desalting of sea water, comprise heat-discharging section circulating brine pipeline [12], and some groups of heat-recovery section flash chamber [1] and the heat-discharging section flash chambers [2] that have condenser pipe [3] and fresh-water tank [10] that are interconnected, it is characterized in that: heat-discharging section circulating brine pipeline [12] is connected with condenser [11] and passes from the upper end of heat-discharging section flash chamber [2], the outlet of heat-discharging section circulating brine pipeline [12] is connected with the bottom of heat-discharging section final stage flash chamber [2-1], and the steam (vapor) outlet of upper level heat-discharging section flash chamber [2] is connected with next stage heat-discharging section flash chamber [2] lower end by pipeline, the flash distillation salt solution of heat-discharging section final stage flash chamber [2-1] bottom is connected with the heat-recovery section circulating brine pipeline [13] that is provided with condenser pipe [3-1] that passes heat-recovery section flash chamber [1] upper end by salt water circulating pump [6], also be provided with brine heater [9] on the pipeline of heat-recovery section circulating brine pipeline [13], be connected with the first order flash chamber bottom of heat-recovery section flash chamber [1] after brine heater [9] heating from the circulating brine that heat-recovery section circulating brine pipeline [13] comes out, and the steam (vapor) outlet of upper level heat-recovery section flash chamber [1] is connected with next stage heat-recovery section flash chamber [1] lower end by pipeline.

2, apparatus for heat recoverin multigrade flash desalting of sea water according to claim 1 is characterized in that: the exit of said fresh-water tank [10] also is provided with product water pump [4].

3, apparatus for heat recoverin multigrade flash desalting of sea water according to claim 1 is characterized in that: the bottom of said heat-discharging section final stage flash chamber [2-1] also is provided with a salt solution dredge pump [5] that is connected with the salt solution dredge pump.

4, apparatus for heat recoverin multigrade flash desalting of sea water according to claim 1 is characterized in that: also be provided with face formula heater [7] in the lower end flash distillation salt solution of said heat-recovery section flash chamber [1] and heat-discharging section flash chamber [2].

5, apparatus for heat recoverin multigrade flash desalting of sea water according to claim 1 is characterized in that: the lower end of said heat-recovery section flash chamber [1] and the interior fresh-water tank of heat-discharging section flash chamber [2] [10] also is provided with Si Wang Chu Droplets device [8].

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