High-salt ash pretreatment drying system

Abstract

The utility model discloses a high-salt ash pretreatment drying system, which belongs to the technical field of pollutant control, and comprises a wastewater drying subsystem, the high-salt ash drying subsystem comprises a boiling fluidized drying bed, the boiling fluidized drying bed is connected with the wastewater drying subsystem and is used for carrying out secondary drying on the high-salt ash output by the wastewater drying subsystem, and the boiling fluidized drying bed is connected with the wastewater drying subsystem and is used for carrying out secondary drying on the high-salt ash output by the wastewater drying subsystem; the cyclone separator is connected with the boiling fluidized drying bed and is used for separating high-salt ash and flue gas discharged by the boiling fluidized drying bed and inputting the separated high-salt ash into the boiling fluidized drying bed again; according to the system, the wastewater drying subsystem is connected with the high-salt ash drying subsystem, the high-salt ash is subjected to secondary drying through the boiling fluidized drying bed, crystal water is removed, and the technical problem that in the related technology, the crystal water contained in the high-salt ash can affect follow-up resource utilization production of the high-salt ash is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of pollutant control, and more specifically, particularly to a high-salt ash pretreatment drying system. Background Art

[0002] Due to the characteristics of my country's energy structure, the role of coal-fired power plants in the supply of electric energy is still very important. With the continuous improvement of my country's environmental protection standards and the increasingly stringent environmental protection policies, the waste gas and wastewater treatment of coal-fired power plants has received unprecedented attention. In this context, limestone wet desulfurization technology is widely used in coal-fired power plants due to its significant advantages. However, in order to maintain the normal operation of the desulfurization tower and maintain salt balance, a certain amount of desulfurization wastewater needs to be discharged. The desulfurization wastewater contains a high concentration of fly ash, gypsum and dissolved salt. The national environmental protection department has made it clear that this part of the wastewater shall not be discharged. In order to solve this problem, various desulfurization wastewater zero emission technologies have emerged. At present, the most widely used process in domestic coal-fired power plants is the high-temperature flue gas bypass evaporation process. The desulfurization wastewater concentrated by the wastewater concentration system is evaporated by high-temperature flue gas to form high-salt ash containing fly ash, gypsum, dissolved salt and other components.

[0003] However, the high-salt ash after the desulfurization wastewater is dried by high-temperature flue gas still contains 4% of crystal water. The crystal water in the high-salt ash will cause the mechanical properties of the crystal plastic profiles produced by its resource utilization to decrease, affecting the reliability of the crystal plastic profiles. Therefore, it is necessary to remove the crystal water in the high-salt ash. Utility Model Content

[0004] The utility model aims to solve the technical problem that the high-salt ash obtained by drying in the prior art contains crystal water, which affects its subsequent resource utilization, and proposes a high-salt ash pretreatment drying system.

[0005] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0006] A high-salt ash pretreatment drying system, the high-salt ash pretreatment drying system is connected to a wastewater concentration system of a boiler flue gas desulfurization system bypass, and the high-salt ash pretreatment drying system comprises:

[0007] A wastewater drying subsystem, wherein the wastewater drying subsystem is used to dry the desulfurized wastewater outputted from the wastewater concentration system into high-salt ash;

[0008] A high-salt ash drying subsystem, the high-salt ash drying subsystem comprising:

[0009] A boiling fluidized bed dryer, the boiling fluidized bed dryer is connected to the wastewater drying subsystem and is used for secondary drying of high-salt ash output from the wastewater drying subsystem;

[0010] A cyclone separator is connected to the boiling fluidized bed dryer and is used to separate the high-salt ash and flue gas discharged from the boiling fluidized bed dryer, and to input the separated high-salt ash into the boiling fluidized bed dryer again.

[0011] Furthermore, the wastewater drying subsystem includes: a drying tower, a rotary atomizer disposed on the top of the drying tower, and an electrostatic precipitator connected to the air outlet of the drying tower;

[0012] The rotary atomizer is connected to the wastewater concentration system and is used to atomize the desulfurization wastewater into liquid particles and then input them into the drying tower.

[0013] Furthermore, the air inlet of the cyclone separator is connected to the gas outlet of the boiling fluidized bed dryer, the air outlet of the cyclone separator is connected to the air inlet of the electrostatic precipitator, and the material outlet of the cyclone separator is connected to the material inlet of the boiling fluidized bed dryer.

[0014] Furthermore, a first silo pump is provided at the bottom of the drying tower, and the outlet of the first silo pump is connected to the feed port of the boiling fluidized bed dryer; a second silo pump is provided at the bottom of the electrostatic precipitator, and the outlet of the second silo pump is connected to the feed port of the boiling fluidized bed dryer; the discharge port of the boiling fluidized bed is connected to a third silo pump, and the outlet of the third silo pump is connected to the high-salt ash raw material silo.

[0015] Furthermore, the air inlet of the drying tower is connected to a hot secondary fan for introducing hot air for drying desulfurization wastewater into the drying tower; the air inlet of the boiling fluidized bed drying bed is connected to a hot primary fan for introducing hot air for drying high-salt ash into the boiling fluidized bed drying bed; the air outlet of the electrostatic precipitator is connected to an electrostatic precipitator fan for extracting the dedusted flue gas from the electrostatic precipitator.

[0016] Furthermore, the air inlet of the hot secondary air fan is connected to the hot secondary air flue gas duct at the outlet of the air preheater in the boiler flue gas desulfurization system.

[0017] Furthermore, the air inlet of the hot primary air fan is connected to the hot primary air flue gas duct at the outlet of the air preheater in the boiler flue gas desulfurization system.

[0018] The beneficial effects of the utility model are:

[0019] The present application provides a high-salt ash pretreatment drying system that connects a wastewater drying subsystem with a high-salt ash drying subsystem, and performs secondary drying on the high-salt ash through a boiling fluidized drying bed to remove crystal water, thereby solving the technical problem in the related art that the crystal water in high-salt ash will affect its subsequent resource utilization and production. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1A schematic diagram of a high-salt ash pretreatment drying system provided in an embodiment of the utility model;

[0021] The markings in the figure are as follows:

[0022] 1. Wastewater drying subsystem;

[0023] 11. Drying tower; 111. Hot secondary fan; 112. First bin pump; 12. Rotary atomizer; 13. Electrostatic precipitator; 131. Electrostatic precipitator fan; 132. Second bin pump;

[0024] 2. High salt ash drying subsystem;

[0025] 21. Boiling fluidized bed drying bed; 211. Hot primary fan; 212. Third bin pump; 22. Cyclone separator. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0027] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back...) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0028] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0029] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the utility model, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the meaning of "and / or" appearing in the full text includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme that satisfies both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the utility model.

[0030] Example

[0031] See also Figure 1 The illustrated embodiment of the present application provides a high-salt ash pretreatment drying system, which is used as one of the bypass systems of the boiler flue gas desulfurization system in actual applications, and is used to dry the desulfurized wastewater generated by the boiler flue gas desulfurization system to obtain high-salt ash and remove the crystallized water in the high-salt ash; the present application provides a high-salt ash pretreatment drying system including: a wastewater drying subsystem 1 and a high-salt ash drying subsystem 2; wherein the wastewater drying subsystem 1 is connected to the bypass wastewater concentration system of the boiler flue gas desulfurization system, and is used to dry the desulfurized wastewater output by the wastewater concentration system after concentration into high-salt ash; the desulfurized wastewater generated by the boiler flue gas desulfurization system first enters the wastewater concentration system for concentration to form a concentrated slurry. This design can reduce the total water volume of the desulfurized wastewater and reduce the heat required for the wastewater drying subsystem 1 to dry the desulfurized wastewater; the high-salt ash drying subsystem 2 is connected to the wastewater drying subsystem 1, and is used to perform secondary drying on the high-salt ash output by the wastewater drying subsystem 1 to remove the crystallized water in the high-salt ash.

[0032] In this embodiment, the wastewater drying subsystem 1 includes: a drying tower 11, a rotary atomizer 12 and an electrostatic precipitator 13; wherein, the air inlet of the drying tower 11 is connected to a hot secondary fan 111, and hot air is transported to the inside thereof through the hot secondary fan 111; the rotary atomizer 12 is connected to the wastewater concentration system and is arranged at the top of the drying tower 11, and the desulfurized wastewater discharged from the wastewater concentration system enters the rotary atomizer 12, and is atomized into fine liquid particles by the rotary atomizer 12 and then enters the drying tower 11, where it is contacted with the hot air and evaporated and dried to form high-salt ash, which is collected at the bottom of the drying tower 11; the air inlet of the electrostatic precipitator 13 is connected to the air outlet of the drying tower 11, and the air outlet of the electrostatic precipitator 13 is connected to the electrostatic precipitator fan 131, and the high The salt-ash mixed flue gas enters the electrostatic precipitator 13 through the air outlet of the drying tower 11, and the dedusted gas is then extracted from the electrostatic precipitator 13 by the electrostatic precipitator fan 131, and the high-salt ash captured by the electrostatic precipitator 13 is collected at the bottom of the electrostatic precipitator 13; the design of the electrostatic precipitator 13 can separate the high-salt ash in the mixed flue gas, on the one hand, so that the high-salt ash carried out by the flue gas can be collected, and on the other hand, the flue gas containing high-salt ash is prevented from entering other systems and causing impact; in the above technical scheme, a first bin pump 112 is provided at the bottom of the drying tower 11, which is used to pump the high-salt ash at the bottom of the drying tower 11 into the high-salt ash drying subsystem 2; a second bin pump 132 is provided at the bottom of the electrostatic precipitator 13, which is used to pump the high-salt ash captured by the electrostatic precipitator 13 into the high-salt ash drying subsystem 2.

[0033] The high-temperature flue gas bypass evaporation process in the related art is to extract 3% to 5% of the high-temperature flue gas as the heat source medium for drying the desulfurized wastewater. Since the high-temperature flue gas has an extremely high dust content, it will cause wear and blockage of the rotary atomizer 12, which will have an adverse effect on the entire system. As a preferred embodiment of the present application, the air inlet of the hot secondary air fan 111 is connected to the hot secondary air flue gas duct at the outlet of the air preheater in the boiler flue gas desulfurization system, so that the desulfurized wastewater is dried using the 350°C to 400°C hot secondary air output by the air preheater. With this technical solution, since the dust content in the hot secondary air is extremely low, the rotary atomizer 12 can be effectively avoided from being damaged, and the high-salt ash formed after drying the desulfurized wastewater with the hot secondary air has a low chloride ion content, which can reduce the adverse effects of the high-salt ash in subsequent comprehensive utilization. At the same time, since the extracted flue gas comes from the outlet of the air preheater, it can also reduce the impact of the boiler efficiency caused by the reduction in the amount of smoke entering the air preheater due to excessive smoke extraction.

[0034] In this embodiment, in order to perform secondary drying on the high-salt ash output by the wastewater drying subsystem 1, the high-salt ash drying subsystem 2 includes: a boiling fluidized bed dryer 21 and a cyclone separator 22; wherein the air inlet of the boiling fluidized bed dryer 21 is connected to a hot primary air blower 211, and hot air is delivered to the interior thereof through the hot primary air blower 211; the feed inlet of the boiling fluidized bed dryer 21 is connected to the first bin pump 112 and the second bin pump 132; the discharge port of the boiling fluidized bed dryer 21 is connected to the third bin pump 212, and the third bin pump 212 is used to discharge the high-salt ash output by the wastewater drying subsystem 1. 212 is connected to the high-salt ash raw material bin; by adopting the above technical scheme, the high-salt ash is pumped into the boiling fluidized bed 21 through the first bin pump 112 and the second bin pump 132, and is contacted with the hot air rising from the bottom of the boiling fluidized bed 21 for secondary drying to remove the crystal water in the high-salt ash. The dry high-salt ash obtained after the secondary drying is collected around the discharge port of the boiling fluidized bed 21. The dry high-salt ash can be pumped to the high-salt ash bin for centralized storage by the third bin pump 212, so as to facilitate the subsequent resource utilization to prepare crystal plastic profiles;

[0035] The air inlet of the cyclone separator 22 is connected to the gas outlet at the top of the boiling fluidized drying bed 21, the air outlet of the cyclone separator 22 is connected to the air inlet of the electrostatic precipitator 13, and the discharge port of the cyclone separator 22 is connected to the feed port of the boiling fluidized drying bed 21; when drying high-salt ash, the hot air in the boiling fluidized drying bed 21 dries the high-salt ash to form flue gas, which is discharged into the cyclone separator 22 through the gas outlet at the top of the boiling fluidized drying bed 21, and part of the gas carried by the flue gas is discharged into the cyclone separator 22. The high-salt ash brought into the cyclone separator 22 is separated from the flue gas in the cyclone separator 22, and is collected at the discharge port at the bottom of the cyclone separator 22, and returns to the boiling fluidized bed 21 again; the flue gas is transported to the electrostatic precipitator 13 to further remove the high-salt ash; this technical solution can effectively remove the crystal water in the high-salt ash, and implement two-stage filtration on the flue gas leaving the boiling fluidized bed 21, so as to fully capture the high-salt ash carried in the flue gas and ensure the yield of dry high-salt ash.

[0036] As a preferred embodiment of the present application, the air inlet of the hot primary air fan 211 is connected to the hot primary air flue gas duct at the outlet of the air preheater in the boiler flue gas desulfurization system, so that the hot primary air at 300-340°C output by the air preheater is used to carry out secondary drying of the high-salt ash; the temperature of the hot primary air is lower than that of the hot secondary air, and it has the characteristics of high wind pressure and large flow, and has good drying performance, which can meet the air volume requirement of the boiling fluidized bed drying bed 21, fully dry the high-salt ash, and remove the crystallized water in the high-salt ash.

[0037] A high-salt ash pretreatment drying system provided by the present application connects a wastewater drying subsystem 1 with a high-salt ash drying subsystem 2, and performs secondary drying on the high-salt ash through a boiling fluidized drying bed 21 to remove crystal water, thereby solving the technical problem in the related art that high-salt ash containing crystal water will affect its subsequent resource utilization and production; at the same time, the technical solution of the present application adopts hot air to replace high-temperature flue gas as the drying heat source medium, which can effectively avoid the wear and blockage of the rotary atomizer 12 caused by impurities in the high-temperature flue gas, and all hot air used for drying comes from the flue gas duct at the outlet of the air preheater, making full use of the waste heat of the boiler flue gas desulfurization system, reducing energy waste, and having good energy-saving and environmental protection properties.

[0038] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes within the technical scope disclosed by the present invention according to the technical scheme and the utility model concept of the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A high-salt ash pretreatment drying system, which is connected to a wastewater concentration system of a boiler flue gas desulfurization system bypass, characterized in that: The high-salt ash pretreatment drying system comprises: A wastewater drying subsystem, wherein the wastewater drying subsystem is used to dry the desulfurized wastewater output after concentration by the wastewater concentration system into high-salt ash; A high-salt ash drying subsystem, the high-salt ash drying subsystem comprising: A boiling fluidized bed dryer, the boiling fluidized bed dryer is connected to the wastewater drying subsystem and is used for secondary drying of high-salt ash output from the wastewater drying subsystem; A cyclone separator is connected to the boiling fluidized bed dryer and is used to separate the high-salt ash and flue gas discharged from the boiling fluidized bed dryer, and to input the separated high-salt ash into the boiling fluidized bed dryer again.

2. A high-salt ash pretreatment drying system according to claim 1, characterized in that: The wastewater drying subsystem comprises: a drying tower, a rotary atomizer arranged on the top of the drying tower, and an electric precipitator connected to the air outlet of the drying tower; The rotary atomizer is connected to the wastewater concentration system and is used to atomize the desulfurization wastewater into liquid particles and then input them into the drying tower.

3. A high-salt ash pretreatment drying system according to claim 2, characterized in that: The air inlet of the cyclone separator is connected to the gas outlet of the boiling fluidized bed dryer, the air outlet of the cyclone separator is connected to the air inlet of the electrostatic precipitator, and the material outlet of the cyclone separator is connected to the material feed inlet of the boiling fluidized bed dryer.

4. A high-salt ash pretreatment drying system according to claim 2, characterized in that: A first silo pump is provided at the bottom of the drying tower, and the outlet of the first silo pump is connected to the feed port of the boiling fluidized bed dryer; a second silo pump is provided at the bottom of the electrostatic precipitator, and the outlet of the second silo pump is connected to the feed port of the boiling fluidized bed dryer; a third silo pump is connected to the discharge port of the boiling fluidized bed dryer, and the outlet of the third silo pump is connected to the high-salt ash raw material silo.

5. The high-salt ash pretreatment drying system according to claim 2, characterized in that: The air inlet of the drying tower is connected to a hot secondary fan for introducing hot air for drying desulfurization wastewater into the drying tower; the air inlet of the boiling fluidized bed drying bed is connected to a hot primary fan for introducing hot air for drying high-salt ash into the boiling fluidized bed drying bed; the air outlet of the electrostatic precipitator is connected to an electrostatic precipitator fan for extracting the dedusted flue gas from the electrostatic precipitator.

6. A high-salt ash pretreatment drying system according to claim 5, characterized in that: The air inlet of the hot secondary air fan is communicated with the hot secondary air flue gas pipeline at the outlet of the air preheater of the boiler flue gas desulfurization system.

7. The high-salt ash pretreatment drying system according to claim 5, characterized in that: The air inlet of the hot primary air fan is communicated with the hot primary air flue gas pipeline at the outlet of the air preheater of the boiler flue gas desulfurization system.

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