Papermaking drying cylinder exhaust gas waste heat recovery device

Abstract

The utility model discloses a papermaking drying cylinder waste gas waste heat recovery device which comprises a heat energy absorption unit, a heat energy conversion unit, a heat energy upgrading unit and a heat energy utilization unit, the heat energy absorption unit is used for conducting heat and mass transfer on tail gas exhausted by a drying system so as to recover heat in the tail gas, and water vapor and suspended solids in the tail gas are reduced; the heat energy conversion unit is connected with the heat energy absorption unit and used for converting the heat recovered by the heat energy absorption unit into low-temperature low-pressure water vapor; the heat energy upgrading unit is connected with the heat energy conversion unit and is used for heating and boosting the low-temperature and low-pressure water vapor so as to improve the heat energy quality; and the heat energy utilization unit is connected with the heat energy upgrading unit and is used for applying the high-quality heat energy to hot air heating or a drying cylinder in a production process.

Description

Technical Field

[0001] This utility model relates to a heat recovery device in the papermaking process, and more particularly to a waste heat recovery device for waste gas from papermaking drying cylinders. Background Technology

[0002] In traditional light industry, paper manufacturing has always been recognized as a major consumer of steam. To date, industrial steam generation relies on electricity or coal, resulting in significant consumption of both. Compared to international advanced levels, my country's technological level still lags considerably. Currently, steam energy consumption in the paper industry varies considerably. For commonly used packaging paper, steam consumption can reach 1.05~1.8t / t, meaning that producing one ton of paper can consume up to 1.8 tons of steam. With the development of production technology, paper machines with enclosed hoods have become the mainstream, more energy-efficient production equipment. Enclosed hoods can recover some of the heat generated during drying and also recover waste heat from condensate. However, heat recovery is incomplete, and a large amount of heat is still emitted. Most drying systems suffer from low heat exchange efficiency and insufficient heat release, which also greatly affects steam energy consumption. Furthermore, the exhaust gas contains suspended water vapor, which has a certain impact on the environment. Utility Model Content

[0003] This utility model discloses a waste heat recovery device for waste gas from a paper drying cylinder, comprising: a heat energy absorption unit, a heat energy conversion unit, a heat energy upgrading unit, and a heat energy utilization unit. The heat energy absorption unit is used to transfer heat and mass to the exhaust gas discharged from the drying system to recover heat from the exhaust gas and reduce water vapor and suspended solids in the exhaust gas. The heat energy conversion unit is connected to the heat energy absorption unit and is used to convert the heat recovered by the heat energy absorption unit into low-temperature, low-pressure water vapor. The heat energy upgrading unit is connected to the heat energy conversion unit and is used to raise the temperature and pressure of the low-temperature, low-pressure water vapor to improve its thermal quality. The heat energy utilization unit is connected to the heat energy upgrading unit and is used to apply the high-quality thermal energy to hot air heating or the drying cylinder in the production process. This utility model solves the problems of incomplete heat recovery, low heat exchange efficiency, insufficient heat release, and the environmental impact caused by water vapor containing suspended solids in the exhaust gas in existing papermaking equipment by connecting the heat energy absorption unit, heat energy conversion unit, heat energy upgrading unit, and heat energy utilization unit in series.

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

[0005] A waste heat recovery device for paper drying cylinder exhaust gas includes: a heat energy absorption unit, a heat energy conversion unit, a heat energy upgrading unit, and a heat energy utilization unit.

[0006] The heat absorption unit is used to transfer heat and mass to the exhaust gas discharged from the drying system to recover heat from the exhaust gas and reduce water vapor and suspended matter in the exhaust gas.

[0007] The heat energy conversion unit is connected to the heat energy absorption unit and is used to convert the heat recovered by the heat energy absorption unit into low-temperature, low-pressure water vapor.

[0008] The thermal energy upgrading unit is connected to the thermal energy conversion unit and is used to heat and pressurize low-temperature and low-pressure steam to improve the quality of thermal energy.

[0009] The thermal energy utilization unit is connected to the thermal energy upgrading unit and is used to apply high-quality thermal energy to hot air heating or drying cylinders in the production process.

[0010] Further configuration: The heat energy absorption unit includes: exhaust gas inlet, exhaust gas outlet, gas distributor, packing layer, scrubbing absorption inlet, scrubbing distributor, liquid level controller, and hot water outlet. The exhaust gas discharged from the drying system enters the heat energy absorption unit through the exhaust gas inlet and diffuses through the gas distributor. The diffused exhaust gas rises and enters the packing layer. The scrubbing absorption inlet introduces external water into the heat energy absorption unit, which then flows down through the scrubbing distributor. The water that flows down enters the packing layer and exchanges heat with the exhaust gas before continuing to fall and deposit at the bottom of the heat energy absorption unit. The water deposited at the bottom of the heat energy absorption unit is then transferred from the hot water outlet to the heat energy conversion unit.

[0011] Further configuration includes a low-pressure steam generator for converting recovered heat energy into low-temperature, low-pressure steam.

[0012] Further, the heat energy enhancement unit includes a steam compressor.

[0013] Further configuration includes a steam distributor for the thermal energy utilization unit.

[0014] This invention addresses the problems of incomplete heat recovery, low heat exchange efficiency, insufficient heat release, and environmental impact caused by suspended solids and water vapor in the exhaust gas from the drying system in existing papermaking equipment by connecting a heat absorption unit, a heat conversion unit, a heat quality improvement unit, and a heat utilization unit in series. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the present invention;

[0016] Figure 2 This is a cross-sectional view of the heat energy absorption unit of this utility model;

[0017] In the diagram: Heat absorption unit 1, exhaust gas inlet 11, exhaust gas outlet 12, gas distributor 13, packing layer 14, scrubbing absorption inlet 15, scrubbing distributor 16, liquid level controller 17, hot water outlet 18.

[0018] 2. Thermal energy conversion unit; 3. Thermal energy quality improvement unit; 4. Thermal energy utilization unit. Detailed Implementation

[0019] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings.

[0020] Many specific details are set forth in the following description in order to provide a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0021] Secondly, this utility model is described in detail with reference to the schematic diagrams. When describing the embodiments of this utility model, for ease of explanation, the cross-sectional views showing the device structure may be partially enlarged, not according to the usual scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of this utility model. In addition, in actual manufacturing, the three-dimensional spatial dimensions of length, width, and depth should be included.

[0022] To make the objectives, technical solutions, and advantages of this utility model clearer, the embodiments of this utility model will be described in further detail below with reference to the accompanying drawings.

[0023] Detailed implementation methods: such as Figure 1 and Figure 2 As shown, this utility model provides a waste heat recovery device for waste gas from paper drying cylinders, including a heat energy absorption unit 1, a heat energy conversion unit 2, a heat energy upgrading unit 3, and a heat energy utilization unit 4. These units are interconnected through pipes and interfaces to form an integrated heat energy recovery and utilization system.

[0024] The heat absorption unit 1 is installed on the exhaust gas pipeline of the drying system to transfer heat and mass to the exhaust gas discharged from the drying system. After entering from the exhaust gas inlet 11, the exhaust gas is evenly diffused by the gas distributor 13. The diffused exhaust gas flows upward and enters the packing layer 14, which is filled with a high-efficiency heat and mass transfer material to increase the gas-liquid contact area and thus improve the heat exchange efficiency.

[0025] Meanwhile, external cooling water is introduced into the heat energy absorption unit 1 through the scrubbing absorption inlet 15. The cooling water is evenly sprayed onto the packing layer 14 via the scrubbing distributor 16, allowing it to fully contact the exhaust gas for heat exchange. The heat and some water vapor in the exhaust gas are absorbed by the water, forming a hot water flow that exits through the hot water outlet 18 and is then transferred to the heat energy conversion unit 2. After heat exchange, the exhaust gas temperature is significantly reduced, and it is discharged from the exhaust gas outlet 12, reducing thermal pollution and suspended solids emissions. A liquid level controller 17 is installed at the accumulation point of the hot water flow in the heat energy absorption unit 1. The liquid level controller 17 is linked to the solenoid valve at the scrubbing absorption inlet 15. When the liquid level controller 17 detects that the liquid level is too high, it closes the solenoid valve to prevent the water level from submerging the gas distributor 13.

[0026] The thermal energy conversion unit 2 includes a low-pressure steam generator, which heats the hot water recovered from the thermal energy absorption unit 1 to generate low-temperature, low-pressure steam. The hot water transfers heat through a heat exchanger, evaporating into low-temperature, low-pressure saturated steam at specific temperature and pressure. The low-pressure steam generator efficiently converts the thermal energy of the hot water into steam, improving energy utilization.

[0027] The thermal energy upgrading unit 3 is connected to the thermal energy conversion unit 2 via pipelines and is used to heat and pressurize low-temperature, low-pressure steam. This unit uses a steam compressor as its core equipment to compress and heat the low-temperature, low-pressure steam, thereby improving its enthalpy and quality. The upgraded steam can meet the high-quality thermal energy requirements of the production process.

[0028] The thermal energy utilization unit 4 is connected after the thermal energy upgrading unit 3 and is used to rationally distribute high-quality hot steam and apply it to the production process. Specifically, this includes delivering steam to the hot air heating system of papermaking production or directly using it for heating the drying cylinder via a steam distributor. The steam distributor can flexibly adjust the steam distribution ratio according to process requirements to ensure efficient utilization of thermal energy and further reduce steam energy consumption.

[0029] This invention recovers waste heat from exhaust gas through a heat absorption unit 1, converting it into low-temperature, low-pressure steam via a heat conversion unit. The steam quality is further enhanced by a heat quality improvement unit 3, and finally, the high-quality heat energy is used in the heating process of papermaking by a heat utilization unit 4. Through the organic coordination of its various units, the entire system not only improves heat utilization efficiency but also significantly reduces the environmental impact of exhaust gas emissions, achieving the goals of energy conservation and emission reduction.

[0030] Although the present invention has been described above with reference to embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of the present invention. In particular, as long as there is no structural conflict, the features in the embodiments disclosed in this invention can be combined with each other in any way. The lack of an exhaustive description of these combinations in this specification is merely for the sake of brevity and resource conservation. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A waste heat recovery device for waste gas from paper drying cylinders, characterized in that, The application relates to a heat energy recovery system for a drying system. The heat energy recovery system comprises a heat energy absorption unit (1), a heat energy conversion unit (2), a heat energy upgrading unit (3) and a heat energy utilization unit (4). The heat energy absorption unit (1) is used for heat and mass transfer of tail gas discharged from the drying system to recover heat in the tail gas and reduce water vapor and suspended solids in the tail gas. The heat energy conversion unit (2) is connected with the heat energy absorption unit (1) and is used for converting the recovered heat into low-temperature and low-pressure water vapor. The heat energy upgrading unit (3) is connected with the heat energy conversion unit (2) and is used for increasing the temperature and pressure of the low-temperature and low-pressure water vapor to improve the quality of the heat energy. The heat energy utilization unit (4) is connected with the heat energy upgrading unit (3) and is used for using the high-quality heat energy for hot air heating or drying cylinder in a production process.

2. A papermaking dryer exhaust heat recovery device according to claim 1, characterized in that, The heat energy absorption unit (1) comprises a tail gas inlet (11), a tail gas outlet (12), a gas distributor (13), a filler layer (14), a leaching absorption inlet (15), a leaching distributor (16), a liquid level controller (17) and a hot water outlet (18).

3. A papermaking dryer exhaust heat recovery device according to claim 1, characterized in that, The tail gas discharged from the drying system enters the heat energy absorption unit (1) from the tail gas inlet (11), is diffused by the gas distributor (13), and then is transpired upwards into the filler layer (14).

4. A papermaking dryer exhaust heat recovery device according to claim 1, characterized by The leaching absorption inlet (15) introduces water from outside into the heat energy absorption unit (1), and then the water is leached downwards by the leaching distributor (16).

5. A papermaking dryer exhaust heat recovery device according to claim 1, characterized by The leached water enters the filler layer (14), exchanges heat with the tail gas, and then continues to fall and deposit at the lower part of the heat energy absorption unit (1). The water deposited at the lower part of the heat energy absorption unit (1) is transferred to the heat energy conversion unit (2) from the hot water outlet (18). The heat energy conversion unit (2) comprises a low-pressure steam generator used for converting the recovered heat into low-temperature and low-pressure water vapor. The heat energy upgrading unit (3) comprises a steam compressor. The heat energy utilization unit (4) comprises a steam distributor.

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