阅读说明：本技术 一种用于燃煤电厂脱硫废水浓缩减量的薄膜蒸发装置与方法 (Thin film evaporation device and method for concentration and reduction of desulfurization wastewater of coal-fired power plant ) 是由 陈彪 高强生 刘春红 叶青 冯向东 吴永法 徐浩然 黄斐鹏 张贺 徐威 于 2020-04-09 设计创作，主要内容包括：本发明涉及用于燃煤电厂脱硫废水浓缩减量的薄膜蒸发装置,包括原水泵、循环泵、冷凝水排放泵、增压风机、预热器、蒸发器和冷凝水箱；预热器进口处设有原水泵,预热器出口与蒸发器进口连接,蒸发器内上部设置喷淋盘,喷淋盘下方布置若干个薄膜物袋,喷淋盘上方布置蒸汽母管,每个薄膜物袋上部的管道与蒸汽母管连接,每个薄膜物袋下部的管道与冷凝水母管连接,冷凝水母管与冷凝水箱相通。本发明的有益效果是：本装置利用高分子薄膜作为热交换元件,发挥薄膜热交换性能好、导热系数高的特点,具有高于其他材质的热利用率；同时利用高分子薄膜蒸发系统蒸发浓缩,能最大限度的减小蒸发系统处理规模和结垢倾向。(The invention relates to a thin film evaporation device for concentration and decrement of desulfurization wastewater of a coal-fired power plant, which comprises a raw water pump, a circulating pump, a condensate water discharge pump, a booster fan, a preheater, an evaporator and a condensate water tank, wherein the raw water pump is connected with the circulating pump; the raw water pump is arranged at the inlet of the preheater, the outlet of the preheater is connected with the inlet of the evaporator, the spraying disc is arranged at the upper part in the evaporator, the film bags are arranged below the spraying disc, the steam main pipe is arranged above the spraying disc, the pipeline at the upper part of each film bag is connected with the steam main pipe, the pipeline at the lower part of each film bag is connected with the condensate water main pipe, and the condensate water main pipe is communicated with the condensate water tank. The invention has the beneficial effects that: the device utilizes the polymer film as a heat exchange element, exerts the characteristics of good heat exchange performance and high heat conductivity coefficient of the film, and has higher heat utilization rate than other materials; meanwhile, the polymer film evaporation system is used for evaporation and concentration, so that the treatment scale and the scaling tendency of the evaporation system can be reduced to the maximum extent.)

1. The utility model provides a film evaporation plant that is used for concentrated decrement of coal fired power plant's desulfurization waste water which characterized in that: comprises a raw water pump (1), a circulating pump (2), a condensed water discharge pump (3), a booster fan (4), a preheater (5), an evaporator (6) and a condensed water tank (7); a raw water pump (1) is arranged at the inlet of the preheater (5), the outlet of the preheater (5) is connected with the inlet of an evaporator (6), a spray tray is arranged at the upper part in the evaporator (6), a plurality of film bags are arranged below the spray tray, a steam main pipe is arranged above the spray tray, a pipeline at the upper part of each film bag is connected with the steam main pipe, a pipeline at the lower part of each film bag is connected with a condensate water main pipe, and the condensate water main pipe is communicated with a condensate water tank (7); a discharge port at the bottom of the evaporator (6) is connected with an inlet of the circulating pump (2), and an outlet of the circulating pump (2) is connected with a spraying disc at the upper part of the evaporator (6); the booster fan (4) is respectively connected with a pipeline led out from the middle part of the evaporator (6) and a steam main pipe in the evaporator (6); the outlet of the condensed water tank (7) is connected with the inlet of the condensed water discharge pump (3), and the outlet of the condensed water discharge pump (3) is connected with the preheater (5).

2. The thin film evaporation device for concentration and reduction of desulfurization wastewater of coal-fired power plant according to claim 1, characterized in that: and round holes are uniformly distributed on the spray disc.

3. The thin film evaporation device for concentration and reduction of desulfurization wastewater of coal-fired power plant according to claim 1, characterized in that: the film bag is a high polymer material bag-shaped object made of PPS or PAR, and is formed by pressing two high polymer material films, the film bag is hollow inside, and the upper end and the lower end of the film bag are respectively provided with a pipeline.

4. The thin film evaporation device for concentration and reduction of desulfurization wastewater of coal-fired power plant according to claim 1, characterized in that: and the outlet of the circulating pump (2) is provided with a conductivity meter (8).

5. The thin film evaporation device for concentration and reduction of desulfurization wastewater of coal-fired power plant according to claim 1, characterized in that: and temperature sensors and pressure sensors are respectively arranged at the upper part, the middle part and the lower part of the evaporator (6).

6. The thin film evaporation device for concentration and reduction of desulfurization wastewater of coal-fired power plant according to claim 1, characterized in that: the bottom of the evaporator (6) is provided with a water level gauge.

7. The thin film evaporation device for concentration and reduction of desulfurization wastewater of coal-fired power plant according to claim 1, characterized in that: one path of an outlet of the circulating pump (2) is connected to the spray disc, and the other path of the outlet is connected to a subsequent wastewater zero-discharge curing system.

8. The concentration and reduction method of the thin film evaporation device for concentration and reduction of desulfurization wastewater of coal-fired power plant according to claim 1, characterized by comprising the following steps:

1) raw liquid of power plant desulfurization wastewater after being subjected to turbidity removal and most of divalent scaling factors is lifted by a raw water pump (1) and enters a preheater (5), the raw liquid is preheated by the preheater (5) and then is conveyed to a spray disc at the upper part in an evaporator (6) and is uniformly sprayed onto the outer surface of a film bag, meanwhile, steam pressurized by a booster fan (4) is introduced into the film bag, and the raw liquid and the steam are isolated by a film and perform heat exchange on the surface of the film;

2) the stock solution is evaporated under the negative pressure environment to form steam after heat exchange, the steam is sucked by a booster fan (4) and increases latent heat of the steam after compression, and the pressurized steam is injected into the inner side of the film and is continuously used for the stock solution evaporation, so that heat circulation is established;

3) steam in the film bag is condensed into water drops after heat exchange, condensed water collected by a condensed water main pipe enters a condensed water tank (7), is discharged by a condensed water pump (3) and is used for supplementing stock solution for preheating by a preheater (5) before being discharged;

4) the raw liquid which is not evaporated after heat exchange in the evaporator (6) through the film bag is collected at the bottom of the evaporator (6) and is conveyed to a spraying disc at the upper part in the evaporator (6) through a circulating pump (2) for circulating evaporation.

Technical Field

The invention can be used for concentration and decrement of desulfurization wastewater of a power plant, belongs to the field of wastewater treatment of the power plant, and particularly relates to a process and a device for concentration and decrement of desulfurization wastewater of the power plant by a polymer film evaporation process.

Background

The water quality of the desulfurization waste water is mainly characterized by the pH value of 4-6.5, acidity, high suspended matter content, generally 10000-15000 mg/L, containing trace mercury, lead, chromium and other heavy metal ions and pollutants such as arsenic, selenium, cyanide and the like, and containing a large amount of Ca²⁺、Mg²⁺Cation and Cl^-、HS0₃ ^-、HC0₃ ^-The total amount of dissolved solids (TDS) is 25000-60000 mg/L, and the chloride ion content is 5000-20000 mg/L, so that the desulfurized wastewater has high salt content, high hardness and high chloride ion contentCharacterized by strong corrosivity and scaling property.

With the stricter and stricter restriction on the pollutant discharge of coal-fired power generating sets and the continuous shortage of fresh water resources by national environmental protection policies, the zero discharge of desulfurization wastewater is promoted. And in order to realize the zero discharge of the wastewater of the whole plant, evaporation treatment is required, and the mainstream technology is to separate the desulfurization wastewater into steam and solid waste through a bypass flue evaporation or evaporation crystallization device. If the entire desulfurization waste water is evaporated, high operation costs are inevitably incurred. Therefore, the desulfurization wastewater needs to be subjected to reduction treatment, so that the treatment cost of subsequent evaporation and solidification is reduced.

The main process for desulfurization wastewater decrement treatment adopts a membrane method and a thermal method. The membrane method generally adopts a reverse osmosis method, because the desulfurization wastewater has high salt content and is rich in scaling substances, reverse osmosis is adopted for concentration and decrement, a double-alkali method is firstly adopted for softening, the operation cost is increased, the recovery rate of the system is generally about 50%, the operation pressure is high, the service life of the membrane is also tested, and the maintenance cost is increased. The thermal method adopts an evaporation process which is generally divided into a single-effect evaporation process, a multi-effect evaporation process, a mechanical vapor compression evaporation system and the like, and generally has the problems of easy scaling, high investment cost and high operation cost.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provides a thin film evaporation device and a thin film evaporation method for concentration and decrement of desulfurization wastewater of a coal-fired power plant.

The thin film evaporation device for concentrating and reducing the desulfurization wastewater of the coal-fired power plant comprises a raw water pump, a circulating pump, a condensed water discharge pump, a booster fan, a preheater, an evaporator and a condensed water tank; a raw water pump is arranged at the inlet of the preheater, the outlet of the preheater is connected with the inlet of the evaporator, a spray tray is arranged at the upper part in the evaporator, a plurality of film bags are arranged below the spray tray, a steam main pipe is arranged above the spray tray, a pipeline at the upper part of each film bag is connected with the steam main pipe, a pipeline at the lower part of each film bag is connected with a condensate water main pipe, and the condensate water main pipe is communicated with a condensate water tank; the outlet of the evaporator is connected with the inlet of the circulating pump, and the outlet of the circulating pump is connected with the spray disc on the upper part of the evaporator; the booster fan is respectively connected with a pipeline led out from the middle part of the evaporator and a steam main pipe in the evaporator; the outlet of the condensed water tank is connected with the inlet of a condensed water discharge pump, and the outlet of the condensed water discharge pump is connected with a preheater.

Preferably, the method comprises the following steps: and round holes are uniformly distributed on the spray disc.

Preferably, the method comprises the following steps: the film bag is a high polymer material bag-shaped object made of PPS or PAR, and is formed by pressing two high polymer material films, the film bag is hollow inside, and the upper end and the lower end of the film bag are respectively provided with a pipeline.

Preferably, the method comprises the following steps: and the outlet of the circulating pump is provided with a conductivity meter.

Preferably, the method comprises the following steps: and the upper part, the middle part and the lower part of the evaporator are respectively provided with a temperature sensor and a pressure sensor.

Preferably, the method comprises the following steps: the bottom of the evaporator is provided with a water level gauge.

Preferably, the method comprises the following steps: one path of the outlet of the circulating pump is connected to the spraying disc, and the other path of the outlet of the circulating pump is connected to a subsequent wastewater zero-discharge curing system.

The concentration and decrement method of the thin film evaporation device for concentrating and decrementing the desulfurization wastewater of the coal-fired power plant comprises the following steps:

1) the method comprises the following steps that (1) raw liquid of power plant desulfurization wastewater after turbidity removal and most of divalent scaling factors removal is lifted by a raw water pump to enter a preheater, is preheated by the preheater and then is conveyed to a spraying disc at the upper part in an evaporator, and is uniformly sprayed onto the outer surface of a film bag, meanwhile, steam pressurized by a booster fan is introduced into the film bag, and the raw liquid and the steam are isolated by a film and carry out heat exchange on the surface of the film;

2) the stock solution is evaporated under the negative pressure environment to form steam after heat exchange, the steam is sucked by a booster fan and compressed to increase the latent heat of the steam, and the pressurized steam is injected into the inner side of the film and is continuously used for the stock solution evaporation, so that the heat cycle is established;

3) steam in the film bag is condensed into water drops after heat exchange, condensed water collected by a condensed water main pipe enters a condensed water tank, is discharged by a condensed water pump and is used for supplementing stock solution for preheating by a preheater before being discharged;

4) the raw liquid which is not evaporated after heat exchange in the evaporator through the film bag is collected at the bottom of the evaporator and is conveyed to a spraying disc at the upper part in the evaporator through a circulating pump for circulating evaporation.

The invention has the beneficial effects that:

1. the device utilizes the polymer film as a heat exchange element, exerts the characteristics of good heat exchange performance and high heat conductivity coefficient of the film, and has higher heat utilization rate than other materials; meanwhile, the polymer film evaporation system is used for evaporation and concentration, so that the treatment scale and the scaling tendency of the evaporation system can be reduced to the maximum extent.

2. The device is not easy to scale and corrode, is easy to clean, saves investment, obviously reduces the operation cost of wastewater, and effectively reduces the cost of zero discharge of wastewater of a power plant while realizing concentration and reduction of desulfurization wastewater.

Drawings

FIG. 1 is a process flow diagram of a thin film evaporation device for concentration and reduction of desulfurization wastewater of a coal-fired power plant.

Description of reference numerals: the device comprises a raw water pump 1, a circulating pump 2, a condensed water discharge pump 3, a booster fan 4, a preheater 5, an evaporator 6, a condensed water tank 7 and a conductivity meter 8.

Detailed Description

The present invention will be further described with reference to the following examples. The following examples are set forth merely to aid in the understanding of the invention. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.

This patent is a concentrated decrement device that is fit for desulfurization waste water that limestone wet flue gas desulfurization of power plant produced, its structure includes: the system comprises a raw water pump 1, a circulating pump 2, a condensed water discharge pump 3, a booster fan 4, a preheater 5, an evaporator 6 and a condensed water tank 7. The evaporator 6 is a core component of the device, a spray disc is arranged on the upper portion of the evaporator 6, the evaporator is divided into an upper portion and a lower portion, a plurality of film bags are arranged below the spray disc, a steam main pipe is arranged above the spray disc, a pipeline on the upper portion of each film bag is connected with the steam main pipe, a pipeline on the lower portion of each film bag is connected with a condensate water main pipe, and the condensate water main pipe is communicated with a condensate water tank 7. The outlet of the bottom of the evaporator 6 is connected with the inlet of the circulating pump 2, the outlet of the circulating pump 2 is connected with the spray tray on the upper part of the evaporator 6, the bottom stock solution is sprayed to the upper spray tray, and the spray tray has the function of uniformly spraying the sprayed stock solution to the outer surface of the film bag. The booster fan 4 is respectively connected with a pipeline led out from the middle part of the evaporator 6 and a steam main pipe in the evaporator 6. 7 exports of condensate water tank and the 3 access connection of comdenstion water drainage pump, and 3 exports of comdenstion water drainage pump and 5 access connection of pre-heater utilize the comdenstion water waste heat to preheat the stoste of raw water pump 1 beating, and the comdenstion water discharges to the desulfurization water tank retrieval and utilization.

Round holes with small diameters are uniformly distributed on the spray disc, so that water can be uniformly sprayed to the outer surface of the film bag below.

The film bag is a high polymer material bag made of PPS or PAR, is formed by pressing two high polymer material films, is hollow inside, is communicated with each other by a pipeline at the upper end and the lower end, and is tightly and tightly connected without leakage. The film bag modules are formed by a plurality of film bags, one group or a plurality of groups of film bag modules are arranged in the horizontal cylindrical container (namely the evaporator 6), and the quantity and the size can be selected according to the size of the treated water.

The evaporator adopts the film bag, has the characteristics of high heat exchange coefficient and sufficient heat exchange, has smooth surface and is not easy to adhere, so scaling is not easy to occur, and the corrosion resistance of the polymer film ensures that the evaporator has the characteristics of corrosion resistance and easy cleaning. Meanwhile, the booster fan can continuously swing the film bag due to the suction effect of the steam in the evaporator, and the film bag is also one of the reasons for being not easy to scale.

And a conductivity meter 8 is arranged at an outlet of the circulating pump 2 and used for controlling the concentration rate of the stock solution in the evaporator and discharging the stock solution to a subsequent wastewater zero-discharge evaporation system after the certain conductivity is achieved by 80000-.

The booster fan 4 makes the inside of the evaporator 6 become a micro-negative pressure environment, the steam generated after the stock solution is subjected to heat exchange by the film bag is sucked into the booster fan 4, the stock solution enters the inner side of the film bag after being pressurized and heated by the booster fan 4 to be used as a steam heat source for heat exchange, the working temperature of the evaporator 6 is maintained at 55-60 ℃, the micro-negative pressure inside the evaporator is maintained through the suction of the booster fan, and the working pressure inside the evaporator is as follows: -0.85 KPa to-0.75 KPa, and the temperature difference between the outlet of the booster fan and the interior of the evaporator is 2-3 ℃.

The preheating steam is mainly used for preheating the device when the device is started, and after the steam is generated, the steam is mainly recycled by means of the steam.

The steam pipeline in the evaporator 6 is mainly used for preheating the system during starting and supplementing a small amount during normal operation.

And temperature sensors and pressure sensors are respectively arranged at the upper part, the middle part and the lower part of the evaporator 6 and are used for monitoring the temperature and the pressure in the evaporator.

The bottom of the evaporator 6 is provided with a water level gauge for monitoring the water level, and the normal heat exchange of the film bag can be influenced by the overhigh water level.

One path of an outlet of the circulating pump 2 is connected with the upper spraying disc, and the other path of the outlet is discharged to a subsequent wastewater zero-discharge curing system.

After concentration and decrement of the evaporator, the water quantity can be reduced by 1/4, and the subsequent operation cost of zero discharge of wastewater can be greatly reduced.

The concentration and decrement method of the thin film evaporation device for concentrating and decrementing the desulfurization wastewater of the coal-fired power plant comprises the following steps:

1) the method comprises the following steps that (1) stock solution of power plant desulfurization wastewater subjected to turbidity removal and most of divalent scaling factors removal is lifted by a stock pump 1 to enter a preheater 5, is preheated by the preheater 5 and then is conveyed to a spray disc at the upper part in an evaporator 6 and is uniformly sprayed onto the outer surface of a film bag, meanwhile, steam pressurized by a booster fan 4 is introduced into the film bag, and the stock solution and the steam are isolated by a film and subjected to heat exchange on the surface of the film;

2) the stock solution is evaporated under the negative pressure environment to form steam after heat exchange, the steam is sucked by the booster fan 4 and increases the latent heat of the steam after compression, and the pressurized steam is injected into the inner side of the film and is continuously used for the stock solution evaporation, thereby establishing heat circulation;

3) steam in the film bag is condensed into water drops after heat exchange, condensed water collected by a condensed water main pipe enters a condensed water tank 7, is discharged by a condensed water pump 3 and is used for supplementing stock solution for preheating by a preheater 5 before being discharged;

4) the raw liquid which is not evaporated after heat exchange in the evaporator 6 through the film bag is collected at the bottom of the evaporator 6 and is conveyed to a spraying disc at the upper part in the evaporator 6 through the circulating pump 2 for circulating evaporation.