A bypassed ash precipitation system

Abstract

The utility model relates to a bypass fly ash discharging and crystal precipitation system, first water washing liquid is heated through multistage preheating device, makes the temperature of water washing liquid rise to evaporation temperature, then passes through at least two evaporation crystallization devices, the evaporation crystallization device includes first entering evaporator and evaporating concentration, then enters crystallization separator and carries out crystallization separation, the concentrated solution in evaporation crystallization device reaches the concentration ratio required after discharging, and the concentrated solution is sent to the thick thickener and is concentrated, then the centrifuge is separated out crystalline salt, and the separated mother liquor returns to the evaporation crystallization device, under the premise that the bypass fly ash treatment process realizes the reduction, the resource, the harmlessness, according to the main component of raw material is soluble chloridion and silica etc, the chloridion can be high-temperature fused glass body through evaporation and separation of salt, water insoluble substance, realizes zero discharge of wastewater and resource utilization, still through the whole process adopts micro negative pressure closed type processing, and the tail gas is treated through condensation separation, and is discharged after reaching the standard.

Description

Technical Field

[0001] This utility model relates to the field of packaging cleaning technology, specifically to a bypass ventilation system for removing ash crystals. Background Technology

[0002] For a large-scale bypass vent ash harmless treatment system to operate stably, a sound process flow is essential; this is crucial to the success of the entire system project. Process design primarily addresses the compatibility and rationality of the overall process flow. It considers both the appropriateness of equipment selection and the standardization of equipment to minimize unnecessary non-standard factors, thereby preventing immature process steps and equipment failures that could affect the overall stable operation of the system. In bypass vent ash projects, common problems are concentrated in the evaporation and salt extraction stage, such as low salt extraction rates and toxic gas leaks. Therefore, a highly efficient and environmentally friendly bypass vent ash crystal precipitation system is needed. Utility Model Content

[0003] Therefore, this utility model provides a bypass ventilation ash crystal precipitation system to solve the problems of low salt extraction rate and toxic gas leakage caused by unreasonable system design in the prior art.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] A bypass venting system for precipitating ash crystals involves first heating the washing liquid through a multi-stage preheating device to raise its temperature to the evaporation temperature, and then passing it through at least two evaporation crystallization devices. Each evaporation crystallization device includes an evaporator for evaporation and concentration, followed by a crystallization separator for crystallization separation. Once the concentrated liquid in the evaporation crystallization device reaches the required concentration ratio, it is discharged and sent to a thickener for further concentration. Then, it is separated into crystalline salts by a centrifuge, and the separated mother liquor is returned to the evaporation crystallization device.

[0006] Furthermore, the multi-stage preheating device includes a condensate preheater, a distilled water preheater, and a live steam preheater arranged sequentially from the inlet to the outlet. The heat source distilled water in the distilled water preheater comes from the distilled water after heat exchange in the evaporation and crystallization device.

[0007] Furthermore, the number of evaporation crystallization devices is three, and from the inlet to the outlet, there are sequentially arranged a first-effect evaporator, a first-stage crystallization separator, a second-effect evaporator, a second-stage crystallization separator, a third-effect evaporator, and a third-stage crystallization separator. The mother liquor flowing out of the third-stage crystallization separator is returned to the third-effect evaporator.

[0008] Furthermore, the condensate from the double-effect evaporator and the triple-effect evaporator flows back to the condensate preheater.

[0009] Furthermore, the non-condensable gas generated during the evaporation crystallization process in the evaporation crystallization device enters the non-condensable gas heat exchanger for heat exchange, then enters the gas-liquid separator for separation, and finally is discharged by the vacuum pump group.

[0010] This utility model has the following advantages:

[0011] This utility model discloses a bypass venting ash crystal precipitation system. Under the premise of reducing volume, recycling resources, and rendering harmless, the bypass venting ash treatment process is based on the fact that the main components of the raw material bypass venting ash are soluble chloride salts and water-insoluble substances such as silica. The chloride salts are separated by evaporation, and the water-insoluble substances can be melted at high temperature to make glass, etc., thus realizing zero discharge of wastewater and resource utilization. Furthermore, the entire process adopts a micro-negative pressure closed treatment, and the exhaust gas is treated by condensation separation and discharged after meeting the standards. Attached Figure Description

[0012] To more clearly illustrate the embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0013] The structures, proportions, sizes, etc. illustrated in this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed herein, and are not intended to limit the implementation conditions of this utility model. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that this utility model can produce, should still fall within the scope of the technical content disclosed in this utility model.

[0014] Figure 1 A system structure diagram of a bypass ventilation gray crystal precipitation system provided for an embodiment of this utility model.

[0015] In the picture:

[0016] 1. Condensate preheater; 2. Distilled water preheater; 3. Live steam preheater; 4. First-effect evaporator; 5. First-stage crystallizer; 6. Second-effect evaporator; 7. Second-stage crystallizer; 8. Third-effect evaporator; 9. Third-stage crystallizer; 10. Condensate tank; 11. Distilled water tank; 12. Non-condensable gas heat exchanger; 13. Gas-liquid separator; 14. Thickener; 15. Centrifuge; 16. Mother liquor tank. Detailed Implementation

[0017] The following specific embodiments illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0018] like Figure 1 As shown, a bypass venting ash crystal precipitation system first heats the washing liquid through a multi-stage preheating device to raise its temperature to the evaporation temperature. Specifically, the multi-stage preheating device includes a condensate preheater 1, a distilled water preheater 2, and a live steam preheater 3, arranged sequentially from inlet to outlet. The heat source condensate in the condensate preheater 1 comes from the condensate after heat exchange; the heat source distilled water in the distilled water preheater 2 comes from the distilled water after heat exchange in the evaporation crystallization device; and the heat source live steam in the live steam preheater 3 comes from live steam generated by a boiler or other high-temperature device.

[0019] The washing liquid, heated to its evaporation temperature, passes through at least two evaporation crystallization devices. Each device includes an evaporator for initial concentration and a crystallization separator for final separation. Therefore, the evaporation crystallization device comprises an evaporator and a crystallization separator. The evaporator is a unit operation that increases the solute concentration by heating a portion of the solvent (usually water) in the solution to obtain a concentrated or saturated solution. Its main purpose is concentration, preparing for the subsequent crystallization process. The crystallization separator includes a crystallizer and a solid-liquid separation device, used to precipitate the solute from the saturated or supersaturated solution from the evaporator in crystalline form and efficiently separate the formed crystals from the mother liquor (residual liquid), ultimately obtaining a pure solid product.

[0020] The number of evaporation crystallization devices is preferably three, namely, a first-effect evaporator 4, a first-stage crystallization separator 5, a second-effect evaporator 6, a second-stage crystallization separator 7, a third-effect evaporator 8, and a third-stage crystallization separator 9 are arranged sequentially from the inlet to the outlet. The mother liquor flowing out of the third-stage crystallization separator 9 is returned to the third-effect evaporator 8. Specifically, the washing liquid heated to the evaporation temperature enters the first-effect evaporator 4 for evaporation, with the first-effect evaporation temperature being 135℃. The first-effect evaporated solution enters the first-stage crystallizer 5 for crystallization treatment, followed by solid-liquid separation treatment to separate the crystals. The separated liquid then enters the second-effect evaporator 6 for secondary evaporation, with the second-effect evaporation temperature being 95℃. The second-effect evaporated solution enters the second-stage crystallizer 7 for crystallization treatment, followed by solid-liquid separation treatment to separate the crystals. The separated liquid then enters the third-effect evaporator 8 for tertiary evaporation, with the third-effect evaporation temperature being 65℃. The third-effect evaporated solution enters the third-stage crystallizer 9 for crystallization treatment, followed by solid-liquid separation treatment to separate the crystals. Through three stages of evaporation, crystallization, and separation, the crystals are basically precipitated.

[0021] To save thermal energy, and because the temperature of the subsequent evaporation stage is lower than that of the preceding stage, the condensate from the second-effect evaporator 6 and the third-effect evaporator 8 flows back to the condensate preheater 1, and the condensate from the first-effect evaporator 4 flows back to the distillation water preheater 2. In this technology, a water tank is added between the evaporator and the preheater. Specifically, the condensate from the second-effect evaporator 6 and the third-effect evaporator 8 first flows into the condensate tank 10, and then the condensate in the condensate tank 10 flows into the condensate preheater 1; the condensate from the first-effect evaporator 4 first flows into the distillation water tank 11, and then the distillation water in the distillation water tank 11 flows into the distillation water preheater 2. This design separates the various steps in the process, avoiding system shutdowns due to equipment failure or leakage.

[0022] The non-condensable gas generated during the evaporation and crystallization process enters the non-condensable gas heat exchanger 12 for heat exchange and cooling, further condensing the gas in the non-condensable gas. Then it enters the gas-liquid separator 13 for separation, turning most of the condensed gas into liquid before separation. Finally, the gas that meets the emission conditions is discharged from the system via a vacuum pump group.

[0023] After passing through a multi-stage evaporation and crystallization unit, the concentrated liquid reaches the required concentration ratio and is discharged. The concentrated liquid is then sent to a thickener 14 for further concentration, and then centrifuged 15 to separate the crystalline salts. The separated mother liquor is returned to the final stage of the evaporation and crystallization unit, such as a triple-effect evaporator 8. The crystalline salts precipitated in this technology are mostly potassium chloride, which meets the Class I qualified product standard in Table 1 of GB6549-2011. A mother liquor tank 16 can be installed between the centrifuge 15 and the evaporation and crystallization unit to separate the system and prevent system shutdown due to malfunction or leakage of any equipment.

[0024] Although the present invention has been described in detail above with general descriptions and specific embodiments, some modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A bypass ventilation ash crystal precipitation system, characterized in that: The washing liquid is first heated by a multi-stage preheating device to raise its temperature to the evaporation temperature, and then passes through at least two evaporation crystallization devices. The evaporation crystallization devices include an evaporator for evaporation and concentration, and a crystallization separator for crystallization and separation. After the concentrated liquid in the evaporation crystallization device reaches the required concentration ratio, it is discharged. The concentrated liquid is sent to a thickener for further concentration, and then separated into crystallized salt by a centrifuge. The separated mother liquor is returned to the evaporation crystallization device.

2. A bypassed blowdown ash crystallization system as defined in claim 1, wherein: The multi-stage preheating device includes a condensate preheater, a distilled water preheater, and a live steam preheater arranged sequentially from the inlet to the outlet. The heat source distilled water in the distilled water preheater comes from the distilled water after heat exchange in the evaporation and crystallization device.

3. The bypass ventilation ash crystal precipitation system according to claim 2, characterized in that: The evaporation crystallization device consists of three units, arranged sequentially from inlet to outlet: a first-effect evaporator, a first-stage crystallization separator, a second-effect evaporator, a second-stage crystallization separator, a third-effect evaporator, and a third-stage crystallization separator. The mother liquor flowing out of the third-stage crystallization separator is returned to the third-effect evaporator.

4. A bypass venting ash crystallization system according to claim 3, wherein: The condensate from the double-effect evaporator and the triple-effect evaporator flows back to the condensate preheater.

5. The bypass ventilation ash crystal precipitation system according to claim 1, characterized in that: The non-condensable gas generated during the evaporation and crystallization process in the evaporation crystallization device enters the non-condensable gas heat exchanger for heat exchange, then enters the gas-liquid separator for separation, and finally is discharged by the vacuum pump group.

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