Calcium oxide exhaust gas treatment system

Abstract

This utility model discloses a calcium oxide tail gas treatment system. The system includes a first condenser with a tail gas inlet and a first water outlet; a primary heater connected to the first condenser and having a first water inlet; a secondary heater connected to the primary heater and having a second water inlet and a second water outlet; and a low-temperature absorption heating device with a cooling end and a heating end. The cooling end is connected to the first water outlet and the first water inlet, and the heating end is connected to the second water inlet and the second water outlet. In this application, the low-temperature absorption heating device can fully utilize the heat generated after the tail gas is condensed, achieving secondary heating of the tail gas. The generated heat is fully utilized, thus eliminating the need for additional heat sources and reducing the energy consumption of the calcium oxide tail gas treatment system.

Description

Technical Field

[0001] This utility model relates to the technical field of calcium oxide production equipment, and in particular to a calcium oxide tail gas treatment system. Background Technology

[0002] Calcium oxide is widely used in metallurgy, construction, water treatment, and chemical industries, such as desulfurization in steel production, acid neutralization in wastewater treatment, and limestone cement production. With the continuous optimization of the structure of my country's calcium oxide industry, the market for low-end products is gradually shrinking, while the market for mid-to-high-end products is expanding rapidly, further driving the growth of my country's calcium oxide industry. Currently, the digestion process of calcium oxide generates a large amount of high-temperature water vapor, and the sludge drying process also produces high-temperature, high-humidity, and odorous waste gases. How to treat these exhaust gases is increasingly becoming a concern for society and enterprises.

[0003] In related technologies, the treatment of calcium oxide exhaust gas typically employs a two-stage condensation process. Simply put, this involves using two connected first condensers to treat the high-temperature, high-humidity exhaust gas. Through two-stage condensation, water vapor is removed from the exhaust gas, resulting in a low-temperature, low-humidity gas. The main drawbacks of this method are: in winter or at low temperatures, it can create noticeable hazy trailing phenomena; even tiny aerosol particles can form an aerosol effect; or moisture can freeze and accumulate at the exhaust port, easily causing poor exhaust gas discharge; simultaneously, the heat released during the conversion of high-temperature exhaust gas to low-temperature exhaust gas cannot be fully utilized, leading to high energy consumption in exhaust gas treatment. Summary of the Invention

[0004] The main purpose of this invention is to provide a calcium oxide exhaust gas treatment system, which aims to reduce the occurrence of mist or water vapor condensation at the exhaust port during calcium oxide production in low-temperature environments, while also reducing the energy consumption of exhaust gas treatment.

[0005] To achieve the above objectives, the present invention proposes a calcium oxide tail gas treatment system, comprising:

[0006] The first condenser is equipped with an exhaust gas inlet and a first water outlet;

[0007] A primary heater is connected to the first condenser pipeline and is provided with a first water inlet;

[0008] A secondary heater, connected to the primary heater pipeline, is equipped with a second water inlet, a second water outlet, and an exhaust gas outlet; and

[0009] The low-temperature absorption heating device has a cooling end and a heating end. The cooling end pipeline is connected to the first water outlet and the first water inlet, and the heating end pipeline is connected to the second water inlet and the second water outlet.

[0010] In an optional embodiment, the calcium oxide tail gas treatment system further includes a refrigerant return pipe, the first condenser is provided with a refrigerant inlet, the first-stage heater is provided with a refrigerant outlet, and the refrigerant return pipe connects the refrigerant inlet and the refrigerant outlet.

[0011] In an optional embodiment, the first condenser includes a tube box, condenser tubes, and a plurality of baffles. The tube box forms the exhaust gas inlet, exhaust gas outlet, first water outlet, and refrigerant inlet. The plurality of baffles are spaced apart and installed inside the tube box, forming a condensation channel with the tube box. The condensation channel connects the exhaust gas inlet and the exhaust gas outlet. The condenser tubes are disposed in the condensation channel and connected to the refrigerant inlet and the first water outlet.

[0012] In an optional embodiment, the pipe box is further provided with a condensate return port, which is connected to the condensation channel.

[0013] In an optional embodiment, the low-temperature absorption heating device further includes a first makeup air fan, which is connected to the primary heater and is used to supply air to the primary heater.

[0014] In an optional embodiment, the low-temperature absorption heating device further includes a second makeup air fan connected to the secondary heater for supplying air to the secondary heater.

[0015] In the technical solution of this utility model, the first condenser is provided with an exhaust gas inlet and a first water outlet; the first-stage heater is connected to the first condenser pipeline and is provided with a first water inlet; the second-stage heater is connected to the first-stage heater pipeline and is provided with a second water inlet and a second water outlet; the low-temperature absorption heating device has a cooling end and a heating end, the cooling end pipeline is connected to the first water outlet and the first water inlet, and the heating end pipeline is connected to the second water inlet and the second water outlet.

[0016] In one embodiment, the high-temperature and high-humidity exhaust gas enters the first condenser through the exhaust gas inlet. Under the action of the first condenser, the temperature of the exhaust gas decreases, and the moisture in it condenses and precipitates out, forming a low-temperature and low-humidity exhaust gas. The exhaust gas continues to flow to the primary heater and the secondary heater, which continuously heat the exhaust gas to form a high-temperature and low-humidity exhaust gas. The exhaust gas is then discharged from the exhaust gas outlet of the secondary heater. Since the discharged exhaust gas is high-humidity and low-humidity, the situation of fog or water vapor condensing at the exhaust outlet under low-temperature conditions, which would otherwise lead to poor exhaust, can be avoided. Furthermore, in this application, the high-temperature condensate from the first condenser can flow from the first outlet to the cooling end of the low-temperature absorption heating device. After cooling, it flows into the primary heater through the second inlet, serving as a heating medium to heat the low-temperature, low-humidity exhaust gas. At the high-temperature end, the second inlet, the second outlet, and the low-temperature absorption heating device form a closed water circuit. The high-temperature water further heats the exhaust gas, and the cooled heating medium flows back into the high-temperature end, where it is reheated by the heat released from the cooling end. This cycle repeats continuously. Therefore, it can be seen that in this application, the low-temperature absorption heating device can fully utilize the heat generated after the exhaust gas condenses, achieving secondary heating of the exhaust gas. The generated heat is fully utilized, thus eliminating the need for additional heat sources, resulting in lower energy consumption for the calcium oxide exhaust gas treatment system. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the structure of an embodiment of the calcium oxide tail gas treatment system of this utility model;

[0019] Figure 2 for Figure 1 The diagram shows the working principle of the calcium oxide exhaust gas treatment system.

[0020] Explanation of icon numbers:

[0021] label name label name 100 Calcium oxide exhaust gas treatment system 40 Low-temperature absorption heating equipment 10 First condenser 40a Cooling end 10a Exhaust gas inlet 40b heating end 10b First water outlet 41 generator 10c Condensate return port 42 absorber 20 Primary heater 43 Evaporator 20a First water inlet 44 Second condenser 20b Refrigerant Export 45 pump 30 Secondary heater 50 Refrigerant return pipe 30a Second water inlet 60 First supplementary air unit 30b Second water outlet 70 Second make-up air fan 30c exhaust outlet

[0022] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0023] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0024] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in this utility model embodiment are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0025] Furthermore, the use of terms such as "first" and "second" in this utility model is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this utility model.

[0026] Reference Figure 1 and Figure 2 This utility model proposes a calcium oxide exhaust gas treatment system 100.

[0027] In this embodiment of the utility model, the calcium oxide tail gas treatment system 100 includes: a first condenser 10, which is provided with a tail gas inlet 10a and a first water outlet 10b; a primary heater 20, which is connected to the first condenser 10 by a pipeline and is provided with a first water inlet 20a; a secondary heater 30, which is connected to the primary heater 20 by a pipeline and is provided with a second water inlet 30a, a second water outlet 30b and a tail gas discharge outlet 30c; and a low-temperature absorption heating device 40, which has a cooling end 40a and a heating end 40b, wherein the cooling end 40a is connected by a pipeline to the first water outlet 10b and the first water inlet 20a, and the heating end 40b is connected by a pipeline to the second water inlet 30a and the second water outlet 30b.

[0028] Specifically, in this embodiment, the first condenser 10 includes a tube box, condenser tubes, and multiple baffles. The tube box is a cavity structure made of metal profiles, forming an exhaust gas inlet 10a, an exhaust gas outlet, a first water outlet 10b, and a refrigerant inlet. Multiple baffles are spaced apart and installed inside the tube box, forming a condensation channel. This condensation channel extends in an "S" shape, connecting the exhaust gas inlet 10a and the exhaust gas outlet. The condenser tubes are located within the condensation channel and connected to the refrigerant inlet and the first water outlet 10b. In actual use, exhaust gas enters the condensation channel through the exhaust gas inlet 10a, and refrigerant enters the refrigerant tubes through the refrigerant inlet, exchanging heat with the exhaust gas in the condensation channel. The moisture in the exhaust gas condenses, forming condensate. The refrigerant, now at a higher temperature, flows out through the first water outlet 10b, and the condensed exhaust gas flows from the exhaust gas outlet to the primary heater 20. The condensate flows from the first water outlet 10b to the cooling end 40a of the low-temperature absorption heating device 40. The structure of the first condenser 10 is already a relatively mature existing technology, so it will not be described in detail here.

[0029] The structure of the primary heater 20 and the secondary heater 30 is the same as that of the first condenser 10. The difference is that the primary heater 20 and the secondary heater 30 use a heat medium to exchange heat with the exhaust gas entering them, thereby heating the exhaust gas.

[0030] The low-temperature absorption heating device 40 mainly includes an evaporator 43, an absorber 42, a second condenser 44, and a generator 41. The upper cylinder consists of the evaporator 43 and absorber 42, the lower cylinder consists of the condenser and generator 41, and it also includes a solution heat exchanger, a solution pump, a refrigerant pump, and a vacuum system. During operation, the main body of the low-temperature absorption heating device 40 is under vacuum. Its working principle is as follows: The lithium bromide solution in the generator 41 is heated and concentrated into a concentrated solution. Simultaneously, the generated refrigerant vapor enters the condenser, is cooled by cooling water and condenses into refrigerant water. The refrigerant water is then pumped into the evaporator 43, where it absorbs residual heat from the heat transfer tubes and evaporates, generating refrigerant vapor that enters the absorber 42. The concentrated solution is pumped by the solution pump, absorbs heat in the heat exchanger, and then enters the absorber 42, where it absorbs heat from the concentrated solution cooled by the heat exchanger in the generator 41. The concentrated solution becomes a dilute solution and its temperature rises; the resulting heat is absorbed by the hot water in the heat transfer tubes. This cycle completes the hot water heating process. That is, the heating end 40b is heated by the absorber 42, and the cooling end 40a is cooled by the generator 41, the second condenser 44, and the evaporator 43. The low-temperature absorption heating device 40 is also a relatively mature existing technology, and will not be described in detail here.

[0031] In practical use, the high-temperature and high-humidity exhaust gas enters the first condenser 10 through the exhaust gas inlet 10a. Under the action of the first condenser 10, the temperature of the exhaust gas decreases, and the moisture in it condenses and precipitates out, forming a low-temperature and low-humidity exhaust gas. The exhaust gas continues to flow to the primary heater 20 and the secondary heater 30, which continuously heat the exhaust gas to form a high-temperature and low-humidity exhaust gas. The exhaust gas is then discharged from the exhaust gas outlet 30c of the secondary heater 30. Since the discharged exhaust gas is a high-humidity and low-humidity exhaust gas, it can avoid the situation where fog or water vapor condenses at the exhaust outlet in a low-temperature environment, which would lead to poor exhaust. Furthermore, in this application, the high-temperature condensate from the first condenser 10 can flow from the first outlet 10b to the cooling end 40a of the low-temperature absorption heating device 40. After cooling, it flows into the primary heater 20 through the second inlet 30a, serving as a heating medium to heat the low-temperature, low-humidity exhaust gas. At the high-temperature end, the second inlet 30a, the second outlet 30b, and the low-temperature absorption heating device 40 form a closed water circuit. The high-temperature water further heats the exhaust gas, and the cooled heating medium flows back into the high-temperature end, where it is reheated by the heat released from the cooling end 40a. This cycle repeats continuously. Thus, it can be seen that in this application, the low-temperature absorption heating device 40 can fully utilize the heat generated after the exhaust gas condenses, achieving secondary heating of the exhaust gas. The generated heat is fully utilized, eliminating the need for additional heat sources, thereby reducing the energy consumption of the calcium oxide exhaust gas treatment system 100.

[0032] Furthermore, the calcium oxide tail gas treatment system 100 also includes a refrigerant return pipe 50. The pipe box of the first condenser 10 is provided with a refrigerant inlet, and the primary heater 20 is provided with a refrigerant outlet 20b. The refrigerant return pipe 50 connects the refrigerant inlet and the refrigerant outlet 20b. It should be noted that the refrigerant in this application is water. That is, after heat exchange, the temperature of the hot water in the primary heater 20 decreases, and the lower-temperature hot water can be used as the refrigerant for the first condenser 10, which can significantly reduce the operating cost.

[0033] Furthermore, the pipe box is also equipped with a condensate return port 10c, which is connected to the condensation channel and extends outward. The condensate can flow through the pipe to the calcium oxide production process for recycling.

[0034] In this application, the low-temperature absorption heating device 40 also includes a first make-up air fan 60 and a second make-up air fan 70. The first make-up air fan 60 is connected to the primary heater 20, and the second make-up air fan 70 is connected to the secondary heater 30. The first make-up air fan 60 and the second make-up air fan 70 are used to make up air into the primary heater 20 and the secondary heater 30, respectively. The purpose of making up air is to adjust the relative temperature in the exhaust gas, so as to further avoid the situation where fog or water vapor condenses at the exhaust port in a low-temperature environment, which would lead to poor exhaust.

[0035] Please see again Figure 2 To further illustrate the technical effects of this utility model, the following explanation is provided in conjunction with its specific practical applications.

[0036] Calcium oxide, when mixed with water, undergoes a hydration reaction inside the digester, releasing a large amount of heat and evaporating the water into steam. Under the action of the pump 45, the high-temperature, high-humidity exhaust gas is discharged from the digester and flows through pipelines to the first condenser 10. At this point, the exhaust gas temperature is approximately 80°C. Under the action of the first condenser 10, the exhaust gas temperature drops to approximately 40°C, heat is transferred, and the water in the gas condenses and liquefies. This condensate returns to the digester through the condensate return port 10c for further digestion. The exhaust gas continues to flow to the primary heater 20, where it is heated to approximately 6°C by the heat exchanger. At 5℃, a humidity sensor can be installed in the primary heater 20. This temperature sensor is connected to the first makeup air fan 60 to detect the relative humidity of the exhaust gas in the primary heater 20 in real time. Based on the relative humidity, the makeup air volume and the speed at which the exhaust gas is injected into the first condenser 10 are adjusted. The exhaust gas then enters the secondary heater 30 to continue heating and raising the temperature to about 100℃. After such treatment, the high-temperature and high-humidity exhaust gas is transformed into high-temperature and low-humidity exhaust gas. A temperature sensor can also be installed in the secondary heater 30 to supply air to the secondary heater 30 in real time through the second makeup air fan 70.

[0037] The temperature change during the above-mentioned exhaust gas conversion process is as follows: the water temperature in the first condenser 10 is 40°C. After exchanging heat with the 80°C exhaust gas, the temperature rises to approximately 75°C. After flowing to the cooling end 40a, the temperature drops to 65°C and flows back to the primary heater 20 to become a heat exchanger, reheating the cooled exhaust gas. The secondary heater 30 uses hot water with an initial temperature of 90°C as the heat medium. After passing through the lifting end, i.e., the absorber 42, the water is heated to 100°C and enters the secondary heater 30 to exchange heat with the exhaust gas. Then, it flows back to the absorber 42 for further heating, and so on. As can be seen from the above process, in this application, the low-temperature absorption heating device 40 can fully utilize the heat generated after the exhaust gas is condensed to achieve secondary heating of the exhaust gas. The generated heat can be fully utilized, so there is no need to set up other heat sources. As a result, the calcium oxide exhaust gas treatment system 100 consumes less energy.

[0038] The above description is only a preferred embodiment of the present utility model and does not limit the patent scope of the present utility model. All equivalent structural transformations made under the inventive concept of the present utility model using the contents of the present utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present utility model.

Claims

1. A calcium oxide tail gas treatment system, characterized by, include: The first condenser is equipped with an exhaust gas inlet and a first water outlet; A primary heater is connected to the first condenser pipeline and is provided with a first water inlet; A secondary heater is connected to the pipeline of the primary heater and is provided with a second water inlet, a second water outlet and an exhaust gas outlet; as well as The low-temperature absorption heating device has a cooling end and a heating end. The cooling end pipeline is connected to the first water outlet and the first water inlet, and the heating end pipeline is connected to the second water inlet and the second water outlet.

2. The calcium oxide tail gas treatment system as described in claim 1, characterized in that, The calcium oxide tail gas treatment system also includes a refrigerant return pipe, the first condenser is provided with a refrigerant inlet, the first-stage heater is provided with a refrigerant outlet, and the refrigerant return pipe connects the refrigerant inlet and the refrigerant outlet.

3. The calcium oxide tail gas treatment system as described in claim 2, characterized in that, The first condenser includes a tube box, condenser tubes, and multiple baffles. The tube box forms the exhaust gas inlet, exhaust gas outlet, first water outlet, and refrigerant inlet. The multiple baffles are spaced apart and installed inside the tube box, forming a condensation channel with the tube box. The condensation channel connects the exhaust gas inlet and the exhaust gas outlet. The condenser tubes are disposed inside the condensation channel and connected to the refrigerant inlet and the first water outlet.

4. The calcium oxide tail gas treatment system as described in claim 3, characterized in that, The pipe box is also provided with a condensate return port, which is connected to the condensation channel.

5. The calcium oxide tail gas treatment system according to any one of claims 1 to 4, characterized in that, The low-temperature absorption heating equipment also includes a first makeup air fan, which is connected to the first-stage heater and is used to supply air to the first-stage heater.

6. The calcium oxide tail gas treatment system according to any one of claims 1 to 4, characterized in that, The low-temperature absorption heating equipment also includes a second makeup air fan, which is connected to the secondary heater and is used to supply air to the secondary heater.

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