Oxygen delignification tail gas waste heat utilization system

Abstract

The utility model discloses an oxygen delignification tail gas waste heat utilization system, and belongs to the technical field of waste heat utilization. Comprising a spraying slurry tank, a gas-liquid heat exchanger, a water tank, a slurry washer, a light sewage pool, a tail gas pipe, an exhaust pipe, a first water pipe and a second water pipe, a tail gas pipe for sucking tail gas of the spouting slurry is arranged on the spouting slurry tank, the tail gas pipe is connected with a gas inlet of the gas-liquid heat exchanger, and a gas outlet of the gas-liquid heat exchanger is connected with an exhaust pipe; a liquid inlet of the gas-liquid heat exchanger is used for feeding liquid, and a liquid outlet of the gas-liquid heat exchanger is connected with the water tank; one end of the first water pipe is connected with the pulp washer, the other end of the first water pipe is connected with the light sewage pool and supplies light sewage, and one end of the second water pipe is connected with the water tank and the other end of the second water pipe is connected with the light sewage pool and supplies light sewage. The problems that according to a traditional waste heat utilization scheme, how to heat washing water of the pulp washer through oxygen desorption spraying tail steam, how to fully utilize waste heat and save the steam amount cannot be solved, and operation is affected due to the fact that the tail steam enters the third washing and bleaching floor are solved.

Description

Technical Field

[0001] The utility model relates to the technical field of waste heat utilization, in particular to a waste heat utilization system of oxygen delignification tail steam. Background Art

[0002] The oxygen delignification section uses medium-pressure steam to heat the pulp to 95-105°C to remove lignin. After the reaction in the oxygen delignification tower is completed, the pulp is sprayed from the top into the spray trough. Excess tail steam is discharged from the top of the spray trough. The tail steam temperature is about 90°C. Direct discharge wastes heat. In addition, when the north wind blows, the tail steam enters the third washing and bleaching floor, blocking the view, hindering employee operations, and corroding equipment. The pulp washer uses plate steam light sewage for washing. When light sewage is insufficient, plate steam warm water is added to the light sewage tank and heated with low-pressure steam. The incoming water temperature is 58-62°C, and after passing through the low-pressure steam heater of the pulp washer spray water, it is about 64-68°C, which is lower than the process requirement of 70-75°C. The low washing water temperature affects the cleanliness of the pulp and reduces the pulp outlet temperature of the machine. It is necessary to use medium-pressure steam (1.0MPa) to supplement heating in the pulp washer riser to ensure the reaction temperature, which increases steam consumption. Publication No. CN220624945U discloses a lime kiln exhaust waste heat recovery system comprising: a lime kiln connected to a flue gas duct; a first waste heat recovery assembly comprising a waste heat recovery unit and a heating unit; the waste heat recovery unit being provided with a smoke inlet, a smoke outlet, a return water inlet, and a return water outlet; the smoke inlet being connected to the end of the flue gas duct remote from the lime kiln, and the smoke outlet being connected to a flue gas exhaust duct; a heating unit filled with water and provided with a water inlet and a water outlet; the water inlet being connected to the return water outlet via the water inlet duct, and the water outlet being connected to the return water inlet via the return water duct; and a bypass duct, the ends of the bypass duct being connected to the flue gas duct and the flue gas exhaust duct, respectively, and the end of the flue gas exhaust duct remote from the smoke outlet being connected to the second waste heat recovery assembly. This application not only reduces energy waste but also lowers heating costs, thereby achieving the goals of efficient waste gas utilization and energy conservation. However, the above solution cannot directly use exhaust gas from the oxygen delignification stage to heat the washer spray water. Therefore, it is urgent to use the tail steam released by oxygen degassing to heat the washing water of the pulp washer, make full use of the waste heat and save steam consumption, and solve the problem of tail steam entering the third washing and rinsing floor affecting operations. Summary of the Invention

[0003] The purpose of this utility model is to provide a waste heat utilization system for oxygen delignification tail steam in response to the above problems, so as to solve the problem that traditional waste heat utilization solutions cannot solve the problem of how to use the tail steam sprayed by oxygen delignification to heat the washing water of the pulp washer, make full use of the waste heat and save steam consumption, and the problem that the tail steam enters the third washing and bleaching floor and affects the operation.

[0004] In order to achieve the above-mentioned purpose, the technical solution adopted by the present utility model is:

[0005] A system for utilizing waste heat from oxygen delignification tail gas, comprising a pulp spraying trough, an air-liquid heat exchanger, a water tank, a pulp washer, a light sewage pool, a tail gas pipe, an exhaust pipe, a first water pipe, and a second water pipe; the pulp spraying trough is provided with a tail gas pipe for sucking in the sprayed pulp tail gas, the tail gas pipe is connected to the air inlet of the gas-liquid heat exchanger, and the air outlet of the gas-liquid heat exchanger is connected to the exhaust pipe; the liquid inlet of the gas-liquid heat exchanger is used for liquid intake, and the liquid outlet of the gas-liquid heat exchanger is connected to the water tank; one end of the first water pipe is connected to the pulp washer, and the other end is connected to the light sewage pool and supplies light sewage, and one end of the second water pipe is connected to the water tank, and the other end is connected to the light sewage pool and supplies light sewage.

[0006] Furthermore, it also includes a third water pipe, one end of which is connected to the liquid inlet of the gas-liquid heat exchanger, and the other end is connected to the light sewage pool.

[0007] Furthermore, a first valve is provided on the third water pipe.

[0008] Furthermore, an overflow port is provided on the upper portion of the water tank, and the overflow port is connected to an overflow pipe.

[0009] Furthermore, the second water pipe is connected to the lower part of the water tank, and a water pump, a second valve and a third valve are provided in the middle of the second water pipe. The second valve is located between the water pump and the pulp washer, and the third valve is located between the water pump and the water tank.

[0010] Furthermore, a fourth valve and a fifth valve are provided on the first water pipe, the fourth valve is closer to the light sewage pool than the fifth valve, and the connection between the first water pipe and the second water pipe is located between the fourth valve and the fifth valve.

[0011] Due to the adoption of the above technical solution, the beneficial effects of the utility model are:

[0012] 1. When the present invention is used, the hot exhaust gas is introduced into the gas-liquid heat exchanger through the exhaust pipe above the pulp spraying tank, and converted into hot water in the water tank, thereby collecting the heat of the hot exhaust gas. The hot water is mixed with light sewage to increase the temperature of the light sewage, and then the light sewage is used in the pulp washer. Based on the above, the present invention can realize the utilization of the waste heat of the oxygen delignification tail gas. At the same time, the tail gas is led to a place far away from the washing and bleaching building or to the air treatment system through the exhaust pipe, solving the problem that the traditional waste heat utilization solution cannot solve how to use the oxygen delignification spray tail gas to heat the washing water of the pulp washer, fully utilize the waste heat and save steam consumption, and the problem that the tail gas enters the third washing and bleaching building and affects the operation.

[0013] 2. The utility model is provided with a first valve, a second valve, a third valve, a fourth valve and a fifth valve, so that the flow of the first water pipe, the second water pipe and the third water pipe can be adjusted according to actual usage, which is convenient for flexible use.

[0014] 3. The utility model is provided with a third water pipe, which can introduce part of the light sewage into the switch, and realize that the part of the light sewage is heated and mixed with the light sewage in the first water pipe to increase the temperature of the light sewage in the first water pipe, which can achieve full light sewage and further improve the environmental protection effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is the system structure diagram of the utility model;

[0016] In the attached figure, 1-spraying trough, 2-gas-liquid heat exchanger, 3-water tank, 4-pulp washer, 5-light sewage pool, 6-tail gas pipe, 7-exhaust pipe, 8-first water pipe, 9-second water pipe, 10-third water pipe, 11-first valve, 12-second valve, 13-third valve, 14-fourth valve, 15-fifth valve, 16-water pump, 17-overflow pipe. DETAILED DESCRIPTION

[0017] The specific implementation of the utility model is further described below with reference to the accompanying drawings.

[0018] In the description of the present invention, it should be understood that the terms "center", "length", "width", "up", "down", "vertical", "horizontal", "top", "bottom", "inside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0019] In this utility model, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; they can refer to direct connection or indirect connection through an intermediate medium; they can refer to internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on specific circumstances.

[0020] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0021] See Figure 1 A system for utilizing waste heat from oxygen delignification tail gas comprises a pulp spraying trough 1, an air-liquid heat exchanger 2, a water tank 3, a pulp washer 4, a light sewage pool 5, a tail gas pipe 6, an exhaust pipe 7, a first water pipe 8 and a second water pipe 9; the pulp spraying trough 1 is provided with a tail gas pipe 6 for inhaling the spray pulp tail gas, the tail gas pipe 6 is connected to the air inlet of the gas-liquid heat exchanger 2, and the air outlet of the gas-liquid heat exchanger 2 is connected to the exhaust pipe 7; the liquid inlet of the gas-liquid heat exchanger 2 is used for liquid intake, and the liquid outlet of the gas-liquid heat exchanger 2 is connected to the water tank 3; one end of the first water pipe 8 is connected to the pulp washer 4, and the other end is connected to the light sewage pool 5 and supplies light sewage, and one end of the second water pipe 9 is connected to the water tank 3, and the other end is connected to the second water pipe 9 to the light sewage pool 5 and supplies light sewage. When in use, the hot exhaust gas is introduced into the gas-liquid heat exchanger 2 through the exhaust pipe 6 above the pulp spraying tank 1, and converted into hot water in the water tank 3, so as to collect the heat of the hot exhaust gas. The hot water is mixed with the light sewage to increase the temperature of the light sewage, and then the light sewage is used in the pulp washer 4.

[0022] This embodiment also includes a third water pipe 10, one end of which is connected to the liquid inlet of the gas-liquid heat exchanger 2 and the other end to the light sewage tank 5. A first valve 11 is provided on the third water pipe 10. This third water pipe 10 allows for the introduction of some light sewage into the heat exchanger. This heated light sewage is then mixed with the light sewage in the first water pipe 8, raising the temperature of the light sewage in the first water pipe 8. This allows for complete light sewage treatment, further enhancing environmental protection.

[0023] In this embodiment, an overflow port is provided on the upper portion of the water tank 3 , and the overflow port is connected to the overflow pipe 17 .

[0024] In this embodiment, the second water pipe 9 is connected to the lower part of the water tank 3, and a water pump 16, a second valve 12 and a third valve 13 are provided in the middle of the second water pipe 9. The second valve 12 is located between the water pump 16 and the pulp washer 4, and the third valve 13 is located between the water pump 16 and the water tank 3.

[0025] In this embodiment, a fourth valve 14 and a fifth valve 15 are provided on the first water pipe 8. The fourth valve 14 is closer to the light sewage pool 5 than the fifth valve 15. The connection between the first water pipe 8 and the second water pipe 9 is located between the fourth valve 14 and the fifth valve 15.

[0026] In this embodiment, the first valve 11, the second valve 12, the third valve 13, the fourth valve 14 and the fifth valve 15 can be selected as flow regulating valves. By providing the first valve 11, the second valve 12, the third valve 13, the fourth valve 14 and the fifth valve 15, the flow of the first water pipe 8, the second water pipe 9 and the third water pipe 10 can be regulated. The flow can be adjusted according to actual usage, which is convenient for flexible use.

[0027] The above description is a detailed description of the preferred embodiments of the present invention, but the embodiments are not intended to limit the scope of the patent application of the present invention. All equivalent changes or modifications completed under the technical spirit suggested by the present invention should fall within the patent scope covered by the present invention.

Claims

1. An oxygen delignification tail steam waste heat utilization system, characterized by: It includes a pulp spraying trough, an air-liquid heat exchanger, a water tank, a pulp washer, a light sewage pool, a tail gas pipe, an exhaust pipe, a first water pipe and a second water pipe; the pulp spraying trough is provided with the tail gas pipe for sucking the spray pulp tail gas, the tail gas pipe is connected to the air inlet of the gas-liquid heat exchanger, and the air outlet of the gas-liquid heat exchanger is connected to the exhaust pipe; the liquid inlet of the gas-liquid heat exchanger is used for liquid intake, and the liquid outlet of the gas-liquid heat exchanger is connected to the water tank; one end of the first water pipe is connected to the pulp washer, and the other end is connected to the light sewage pool and supplies light sewage, one end of the second water pipe is connected to the water tank, and the other end is connected to the light sewage pool and supplies light sewage.

2. The oxygen delignification tail steam waste heat utilization system according to claim 1, characterized in that: It also includes a third water pipe, one end of which is connected to the liquid inlet of the gas-liquid heat exchanger, and the other end is connected to the light sewage pool.

3. The oxygen delignification tail steam waste heat utilization system according to claim 2, characterized in that: The third water pipe is provided with a first valve.

4. The oxygen delignification tail steam waste heat utilization system according to claim 1, characterized in that: An overflow port is provided on the upper portion of the water tank, and the overflow port is connected to an overflow pipe.

5. The oxygen delignification tail steam waste heat utilization system according to claim 1, characterized in that: The second water pipe is connected to the lower part of the water tank. A water pump, a second valve and a third valve are provided in the middle of the second water pipe. The second valve is located between the water pump and the pulp washer, and the third valve is located between the water pump and the water tank.

6. The oxygen delignification tail steam waste heat utilization system according to claim 1, characterized in that: The first water pipe is provided with a fourth valve and a fifth valve. The fourth valve is closer to the light sewage pool than the fifth valve. The connection between the first water pipe and the second water pipe is located between the fourth valve and the fifth valve.

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