CN210394055U - System for purifying potassium and sodium salts of fly ash water washing liquid according to quality - Google Patents

Abstract

The utility model relates to a system for separating and purifying potassium and sodium salts of fly ash water washing liquid. Evaporation system, the cooling kettle is also connected with a vacuum system and a MVR water supply tank, the decanter centrifuge is also connected with a fine salt tank, and the fine salt tank is connected with a sodium salt centrifuge. The system of the utility model can realize the effective separation of sodium chloride and potassium chloride in the fly ash water washing liquid, obtain high-purity potassium chloride product, the purity of potassium chloride can reach 92%, reduce the cost of fly ash disposal, alleviate the The enrichment degree of fine salt in the MVR system promotes the continuous and stable operation of the MVR system, and prolongs the period of the crystallization separator scarring and salt formation caused by the fine salt in the MVR system.

Description

A kind of fly ash water washing liquid potassium and sodium salt quality purification system

technical field

The utility model belongs to the technical field of hazardous waste treatment, in particular to a purification system for potassium and sodium salts of fly ash water washing solution.

Background technique

MVR is the abbreviation of mechanical vapor recompression technology. It uses the secondary steam and its energy generated by the evaporation system itself, and compresses the steam compressor to do work to increase the thermal energy of the secondary steam. An energy-saving technology that meets the needs of external energy, it is currently widely used in the fields of chemical industry, food, papermaking, medicine, seawater desalination and sewage treatment.

Waste fly ash refers to the residue collected in the flue gas purification system of waste incineration power plants, and contains soluble substances such as chloride ions, sodium chloride, potassium chloride, etc. In order to facilitate the disposal of waste fly ash in cement kilns, it is usually removed by washing with water. the above substances. The washing liquid produced after washing the waste fly ash needs to be further processed because it contains a relatively high concentration of chloride salts (mainly containing sodium chloride and potassium chloride). At present, the MVR system is used for the evaporation and desalination treatment of the fly ash water washing liquid. During the operation of the MVR system, the problems of wall formation, scarring and blockage due to the continuous enrichment of potassium chloride are likely to occur, resulting in shutdown and mother liquor emptying operations, which affect the MVR system. continuous operation.

In order to ensure the continuous operation of the MVR system and realize the classification and recovery of potassium chloride and sodium chloride resources in the fly ash washing solution, CN206793091U discloses a potassium-sodium salt separation system combined with the MVR system. And the main process of centrifugation, when potassium chloride treats the critical saturation point, the salt mother liquor is subjected to heat preservation filtration, cooling crystallization, centrifugal separation and other processes to achieve effective separation of potassium chloride and obtain high-purity potassium chloride products, However, there are problems such as the reflux of the potassium salt mother liquor affecting the evaporation of the MVR system, the difficulty in establishing the balance between the old and the new system, the low purity of the recovered potassium chloride, and the low recovery efficiency, which need to be further optimized.

In view of the above reasons, the present invention is proposed.

Utility model content

In order to solve the above problems existing in the prior art, the utility model provides a purification system for potassium and sodium salts of fly ash water washing solution. The system of the utility model can realize the effective separation of potassium chloride and obtain high-purity potassium chloride products. , reduce the cost of fly ash disposal, ease the concentration of fine salt in the MVR system, promote the continuous and stable operation of the MVR system, and prolong the period of the crystallization separator scarring and salt formation caused by the fine salt in the MVR system.

In order to achieve the above purpose, the utility model adopts the following technical solutions:

A system for purifying potassium and sodium salts of fly ash water washing liquid, comprising a thickener, a cooling kettle, a decanter centrifuge, a potash mother liquor tank, a potash mother liquor heat exchanger, and an MVR evaporation system connected in sequence, and the cooling kettle Also connected is the vacuum system and the MVR water supply tank.

The MVR water supply tank, thickener, sodium salt centrifuge and MVR evaporation system described in the utility model all belong to the existing structure of the MVR system.

The stock solution in the MVR water supply tank enters the cooling kettle, and the stock solution is unsaturated brine, which is used for the salt washing operation in the cooling kettle.

In addition, when the fine salt enrichment state of the MVR system is serious, the solid content of the penetrating mother liquor is 15-50%, which contains a large amount of fine salt. The system runs stably. At this time, the penetrating mother liquor in the sodium salt centrifuge is pumped into the decanter centrifuge to completely separate the fine salt and eliminate the influence of the fine salt circulation on the evaporation system.

Further, the vacuum pumping system includes a first gas-liquid separator, a steam condenser, a second gas-liquid separator and a double-ring vacuum pump which are connected in sequence.

Further, the first gas-liquid separator is connected with the cooling kettle.

The method of the utility model adopts the combination of flash evaporation and circulating water cooling under the vacuum condition in the cooling kettle, which can realize the rapid cooling of materials.

Further, the first gas-liquid separator is provided with a first liquid discharge port, the second gas-liquid separator is provided with a second liquid discharge port, the first liquid discharge port and the second liquid discharge port are provided. The liquid discharge ports are all connected with the described potassium salt mother liquor tank.

Further, the steam condenser is provided with a water inlet and a water outlet, and the steam condenser is cooled by circulating water.

Further, described potash mother liquor tank is also connected with MVR accident pool.

Further, the cooling kettle is provided with a cooling water inlet and a cooling water outlet, and the cooling kettle is cooled by circulating water.

Further, the potash mother liquor heat exchanger is provided with a steam inlet and a steam outlet, and the potash mother liquor heat exchanger heats the potash mother liquor by steam.

Further, the decanter centrifuge is also connected with a fine salt tank, and the fine salt tank is connected with the sodium salt centrifuge.

Further, the cooling kettle is an enamel kettle.

The utility model also provides a method for utilizing the system to purify potassium and sodium in the fly ash water washing solution, comprising the following steps:

First, the supernatant in the thickener is pumped into the cooling kettle, and then the unsaturated brine in the MVR water supply tank is pumped into the cooling kettle, and the supernatant in the thickener is washed and salted, through vacuum flashing and circulation The combined cooling method of cooling water realizes the rapid cooling and crystallization of materials to separate out potassium chloride crystals, then all enter the decanter centrifuge for separation to obtain potassium chloride crystals and potassium chloride mother liquor, and the potassium chloride mother liquor enters the potassium salt mother liquor The tank is then heated to 100 ℃ by the potassium salt mother liquor heat exchanger, and returned to the MVR evaporation system. In the salt tank, then pump into the decanter centrifuge to separate the fine salt and the fine salt mother liquor, and the fine salt mother liquor enters the potash mother liquor tank, then is heated to 100 ℃ by the potash mother liquor heat exchanger, and returns to the MVR Evaporation system.

Further, the cooling kettle was cooled to 38-42°C.

Preferably, the temperature is lowered to 40°C.

More preferably, the cooling kettle is evacuated by a vacuum system.

Further, when the fine salt enrichment state of the MVR system is serious, the solid content of the penetrating mother liquor is 15-50%.

Compared with the prior art, the beneficial effects of the present utility model are:

The system of the utility model can realize the effective separation of sodium chloride and potassium chloride in the fly ash washing liquid, obtain high-purity potassium chloride product, the purity of potassium chloride can reach 92%, reduce the cost of fly ash disposal, and alleviate the The enrichment degree of fine salt in the MVR system promotes the continuous and stable operation of the MVR system, and prolongs the period of the crystallization separator scarring and salt formation caused by the fine salt in the MVR system; potassium chloride and chloride are respectively extracted from the fly ash washing solution. Sodium resources, realizing the recycling of resources, making the cement kiln co-processing fly ash technology more perfect, and promoting its promotion and application nationwide; by adding potassium and sodium salt separation and fine salt elimination systems, not only can new potassium chloride products be obtained sales revenue, and significantly increase the amount of fly ash disposal.

Description of drawings

In order to more clearly illustrate the embodiments of the present utility model or the technical solutions in the prior art, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description These are just some embodiments of the present invention, and for those of ordinary skill in the art, other drawings can also be obtained from these drawings without creative effort.

Fig. 1 is the flow chart of the quality purification system of fly ash water washing liquid potassium and sodium salt of the present invention.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention more clear, the technical solutions of the present invention will be described in detail below. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other implementations obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present invention.

Example 1

As shown in Figure 1, a kind of fly ash water washing liquid potassium and sodium salt quality purification system, including thickener, cooling kettle, decanter centrifuge, potash mother liquor tank, potash mother liquor heat exchanger, MVR evaporation system connected in turn , the cooling kettle is also connected with a vacuum pumping system and an MVR water supply tank, the decanter centrifuge is also connected with a fine salt tank, and the fine salt tank is connected with a sodium salt centrifuge.

The vacuum pumping system includes a first gas-liquid separator, a steam condenser, a second gas-liquid separator and a double-ring vacuum pump which are connected in sequence, and the first gas-liquid separator is connected with the cooling kettle.

The described vacuuming system ensures that the cooling kettle is cooled under the condition of vacuum, and potassium chloride crystals are obtained through the separation of the decanter centrifuge. The heater adopts steam heat exchange.

The stock solution in the MVR water supply tank enters the cooling kettle, and the stock solution is unsaturated brine, which is used for the salt washing operation in the cooling kettle.

In addition, when the fine salt enrichment state of the MVR system is serious, the solid content of the penetrating mother liquor is 15-50%, which contains a large amount of fine salt. The system runs stably. At this time, the penetrating mother liquor in the sodium salt centrifuge is pumped into the decanter centrifuge to completely separate the fine salt and eliminate the influence of the fine salt circulation on the evaporation system.

The first gas-liquid separator is provided with a first liquid discharge port, the second gas-liquid separator is provided with a second liquid discharge port, the first liquid discharge port and the second liquid discharge port All are connected with the described potassium salt mother liquor tank. The liquid phase separated by the first gas-liquid separator and the second gas-liquid separator flows into the potassium salt mother liquor tank through the liquid discharge port for the next step, and the non-condensable gas is discharged through the double-ring vacuum pump.

The steam condenser is provided with a water inlet and a water outlet, and the steam condenser is cooled by circulating water.

Described potash mother liquor tank is also connected with MVR accident pool. In case of emergency, all the feed liquid in the potassium and sodium salt purification system can be discharged into the MVR accident pool for processing.

In a preferred solution, the cooling kettle is provided with a cooling water inlet and a cooling water outlet, and the cooling kettle is cooled by circulating water. The potash mother liquor heat exchanger is provided with a steam inlet and a steam outlet, the potash mother liquor heat exchanger heats the potash mother liquor by steam, and the cooling kettle described in this embodiment is an enamel kettle.

The purity of potassium chloride separated by the system of this embodiment can reach 92%.

It should be noted that the MVR water supply tank, thickener, sodium salt centrifuge, and MVR evaporation system described in this embodiment all belong to the MVR system, and the system of the present invention and the MVR system operate simultaneously. Sodium chloride is obtained from the salt production unit of the MVR system.

Example 2

The present embodiment utilizes the described system to purify the method for potassium and sodium in the fly ash water washing solution, comprising the following steps:

First, pump the supernatant in the thickener into the cooling kettle, and then pump the unsaturated brine in the MVR water supply tank into the cooling kettle to wash and salt the supernatant in the thickener, through vacuum flash evaporation and The combined cooling method of circulating cooling water realizes rapid cooling and crystallization of materials to separate out potassium chloride crystals, then all enter the decanter centrifuge for separation to obtain potassium chloride crystals and potassium chloride mother liquor, and the potassium chloride mother liquor enters the potassium salt The mother liquor tank is then heated to 100°C through the potassium salt mother liquor heat exchanger and returned to the MVR evaporation system. At the same time, when the fine salt enrichment state of the MVR system is serious, the fine salt and the fine salt mother liquor are obtained by separating the fine salt and the fine salt mother liquor by pumping the sodium salt centrifuge through the mother liquor into the fine salt tank, and then pumping into the decanter centrifuge. The salt mother liquor enters the potash mother liquor tank, then is heated to 100 ℃ through the potash mother liquor heat exchanger, and returns to the MVR evaporation system.

The vacuum pumping system includes a first gas-liquid separator, a steam condenser, a second gas-liquid separator and a double-ring vacuum pump which are connected in sequence, and the first gas-liquid separator is connected with the cooling kettle. The first gas-liquid separator is provided with a first liquid discharge port, the second gas-liquid separator is provided with a second liquid discharge port, the first liquid discharge port and the second liquid discharge port All are connected with the described potassium salt mother liquor tank.

The described vacuuming system ensures that the cooling kettle is cooled under the condition of vacuum, and potassium chloride crystals are obtained through the separation of the decanter centrifuge. The heater adopts steam heat exchange.

The method of the utility model adopts the technology of vacuum flash evaporation and circulating water cooling. The supernatant liquid in the thickener is extracted and pumped into a cooling kettle, and the temperature is lowered to 40 DEG C, and potassium chloride crystals are obtained through centrifugal separation, and the potassium salt mother liquor is passed through steam After heating and heating, it is refluxed into the MVR evaporation system.

The cooling process in the cooling kettle is flash cooling, which adopts the combination of vacuum flash evaporation and circulating water cooling to achieve rapid cooling of materials. The stock solution in the MVR water supply tank enters the cooling kettle, and the stock solution is unsaturated brine, which is used for the salt washing operation in the cooling kettle, which can redissolve a small amount of impurity NaCl and improve the purity of the potassium salt. In addition, when the fine salt enrichment state of the MVR system is serious, the solid content of the penetrating mother liquor is 15-50%, which contains a large amount of fine salt. The system runs stably. At this time, the penetrating mother liquor in the sodium salt centrifuge is pumped into the decanter centrifuge to completely separate the fine salt and eliminate the influence of the fine salt circulation on the evaporation system.

The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited to this. Replacement should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims (10)

1. The system is characterized by comprising a thickener, a cooling kettle, a horizontal screw centrifuge, a sylvite mother liquor tank, a sylvite mother liquor heat exchanger and an MVR evaporation system which are sequentially connected, wherein the cooling kettle is further connected with a vacuum pumping system and an MVR water supply tank.

2. The system for purifying the fly ash water washing liquid potassium sodium salt according to claim 1, wherein the vacuum pumping system comprises a first gas-liquid separator, a steam condenser, a second gas-liquid separator and a double-ring vacuum pump which are sequentially connected.

3. The system for purifying the fly ash water washing solution potassium sodium salt according to claim 2, wherein the first gas-liquid separator is connected with the cooling kettle.

4. The system for purifying potassium salt and sodium salt in fly ash washing liquid according to claim 3, wherein a first liquid discharge port is formed in the first gas-liquid separator, a second liquid discharge port is formed in the second gas-liquid separator, and the first liquid discharge port and the second liquid discharge port are both connected with the potassium salt mother liquid tank.

5. The system for purifying the fly ash water washing solution potassium sodium salt according to claim 3, wherein the steam condenser is provided with a water inlet and a water outlet, and the steam condenser is cooled by circulating water.

6. The system for purifying potassium salt and sodium salt of fly ash washing solution according to claim 1, wherein the potassium salt mother liquor tank is further connected with an MVR accident tank.

7. The system for purifying the fly ash water washing solution potassium sodium salt according to claim 1, wherein a cooling water inlet and a cooling water outlet are arranged on the cooling kettle, and the cooling kettle is cooled by circulating water.

8. The system for purifying potassium salt and sodium salt of fly ash washing liquid according to claim 1, wherein a steam inlet and a steam outlet are arranged on the potassium salt mother liquid heat exchanger, and the potassium salt mother liquid heat exchanger heats potassium salt mother liquid through steam.

9. The system for purifying the potassium salt and the sodium salt in the fly ash water washing liquid according to any one of claims 1 to 8, wherein the horizontal screw centrifuge is further connected with a fine salt tank, and the fine salt tank is connected with a sodium salt centrifuge.

10. The system for purifying the potassium sodium salt in the fly ash water washing liquid according to any one of claims 1 to 8, wherein the cooling kettle is an enamel kettle.

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