CN-121974543-A - Sludge drying system based on absorption heat pump and control method thereof

CN121974543ACN 121974543 ACN121974543 ACN 121974543ACN-121974543-A

Abstract

The invention provides a sludge drying system based on an absorption heat pump and a control method thereof. The sludge drying system comprises a sludge drying chamber, an absorption heat pump and a closed cooling tower, wherein an air inlet and an air outlet of the sludge drying chamber are arranged in a sludge region of the sludge drying chamber, a first cooling water pipeline is arranged from a cooling water outlet of the absorption heat pump to a cooling water inlet of the closed cooling tower, a second cooling water pipeline is arranged from a cooling water outlet of the closed cooling tower to a cooling water inlet of the sludge drying chamber, a third cooling water pipeline is arranged from a cooling water outlet of the sludge drying chamber to a cooling water inlet of the absorption heat pump to form a first cooling water circulation, a first hot water pipeline is arranged from a hot water outlet of the absorption heat pump to a hot water inlet of the sludge drying chamber, a second hot water pipeline is arranged from a hot water outlet of the sludge drying chamber to a hot water inlet of the absorption heat pump to form a first hot water circulation, and the water inlet temperature of the absorption heat pump is 60-65 ℃. The sludge drying system and the control method can enable the absorption heat pump to stably operate, save the steam consumption and improve the energy efficiency of the heat pump.

Inventors

LV YANG
ZHANG HEQING
ZHANG FANG
LI XIAOJIN
CHANG SHAOYING
WANG ZHEXIAO
YANG TONG
XIA MAOCHUAN
XIAO BO
BI YONGWEI

Assignees

国能龙源环保有限公司
中建环能科技股份有限公司

Dates

Publication Date: 20260505
Application Date: 20260108

Claims (10)

1. A sludge drying system based on an absorption heat pump is characterized by comprising a sludge drying chamber (1), an absorption heat pump (2) and a closed cooling tower (3) which are communicated through pipelines, The sludge drying chamber (1) comprises a cooling water circulation zone, a hot water circulation zone and a sludge zone, wherein an air inlet and an air outlet of the sludge drying chamber (1) are arranged in the sludge zone and are used for air inlet from the sludge zone to dry and cool and humidify the sludge in the sludge zone, air outlet from the sludge zone and return air to the cooling water circulation zone to dehumidify and cool, and then the sludge is sent to the hot water circulation zone to heat, and then air is again inlet to the sludge zone to form air circulation; A first cooling water pipeline (6) is arranged from a cooling water outlet of the absorption heat pump (2) to a cooling water inlet of the closed cooling tower (3), a second cooling water pipeline (7) is arranged from the cooling water outlet of the closed cooling tower (3) to a cooling water inlet of the sludge drying chamber (1), a third cooling water pipeline (8) is arranged from the cooling water outlet of the sludge drying chamber (1) to a cooling water inlet of the absorption heat pump (2), and the sludge drying chamber (1) and the absorption heat pump (2) form a first cooling water circulation through the second cooling water pipeline (7), the third cooling water pipeline (8) and the first cooling water pipeline (6) so as to enable cooling water to exchange heat with return air from the sludge region in the cooling water circulation region and then circulate to the absorption heat pump (2) to provide heat; A first hot water pipeline (4) is arranged from a hot water outlet of the absorption heat pump (2) to a hot water inlet of the sludge drying chamber (1), a second hot water pipeline (5) is arranged from a hot water outlet of the sludge drying chamber (1) to a hot water inlet of the absorption heat pump (2), and the sludge drying chamber (1) and the absorption heat pump (2) form a first hot water circulation through the first hot water pipeline (4) and the second hot water pipeline (5) so as to exchange heat with return air from the cooling water circulation zone in the hot water circulation zone and then circulate to the absorption heat pump (2) to absorb heat; the water inlet temperature of the hot water inlet of the absorption heat pump (2) is 60-65 ℃.
2. A sludge drying system as claimed in claim 1, wherein, A third hot water pipeline (9) is arranged from the water inlet end of the second hot water pipeline (5) to the hot water inlet of the closed cooling tower (3); a fourth hot water pipeline (10) is arranged from the hot water outlet of the closed cooling tower (3) to the water outlet end of the second hot water pipeline (5); The sludge drying chamber (1) and the absorption heat pump (2) form a second hot water circulation through the third hot water pipeline (9), the closed cooling tower (3) and the fourth hot water pipeline (10), and the second hot water circulation is used for recycling hot water output by the sludge drying chamber (1) to the absorption heat pump (2) for hot water circulation after being cooled by the closed cooling tower (3) when the water inlet temperature of a hot water inlet of the absorption heat pump (2) is more than 65 ℃.
3. The sludge drying system according to claim 1 or 2, characterized in that the inlet water temperature of the cooling water inlet of the absorption heat pump (2) is 40-45 ℃.
4. A sludge drying system as claimed in claim 3, wherein, A fourth cooling water pipeline (11) is arranged from the water inlet end of the first cooling water pipeline (6) to the outlet end of the second cooling water pipeline (7); The sludge drying chamber (1) and the absorption heat pump (2) form a second cooling water circulation through the fourth cooling water pipeline (11) and the third cooling water pipeline (8), and the second cooling water circulation is used for directly sending cooling water output by the absorption heat pump (2) to the sludge drying chamber (1) to exchange heat with wind and raise the temperature when the water inlet temperature of a cooling water inlet of the absorption heat pump (2) is less than 40 ℃.
5. The sludge drying system as claimed in claim 4, wherein, The air inlet temperature of the sludge drying chamber (1) is 65-80 ℃; preferably, the relative humidity of the inlet air of the sludge drying chamber (1) is less than 30%.
6. The sludge drying system as claimed in claim 4, wherein, The first cooling water pipeline (6) is provided with a first cooling water circulating pump (61), and/or, The second cooling water pipeline (7) is provided with a second cooling water circulating pump (71), and/or, A third cooling water circulating pump (81) is arranged on the third cooling water pipeline (8), and/or, The first hot water pipeline (4) is provided with a first hot water circulating pump (41), and/or, A second hot water circulating pump (51) is arranged on the second hot water pipeline (5), and/or, A third hot water circulating pump (91) is arranged on the third hot water pipeline (9), and/or, A fourth hot water circulating pump (101) is arranged on the fourth hot water pipeline (10), and/or, A fourth cooling water circulating pump (111) is arranged on the fourth cooling water pipeline (11).
7. The sludge drying system as claimed in any one of claims 1 to 6, wherein, In the sludge drying chamber (1), an air inlet and/or an air outlet of the sludge drying chamber are/is provided with a temperature sensor and a humidity sensor, and/or, In the sludge drying chamber (1), a hot water inlet and/or a hot water outlet of the sludge drying chamber is/are provided with a temperature sensor and/or, A temperature sensor is arranged at a cooling water inlet and/or a cooling water outlet of the sludge drying chamber (1); in the absorption heat pump (2), a hot water inlet and/or a hot water outlet of the absorption heat pump is/are provided with a temperature sensor and/or, In the absorption heat pump (2), a cooling water inlet and/or a cooling water outlet of the absorption heat pump is/are provided with a temperature sensor and/or, In the closed cooling tower (3), a hot water inlet and/or a hot water outlet of the closed cooling tower is/are provided with a temperature sensor and/or, In the closed cooling tower (3), a cooling water inlet and/or a cooling water outlet of the closed cooling tower is/are provided with a temperature sensor.
8. The sludge drying system as claimed in any one of claims 1 to 7, wherein, The first hot water pipeline (4) is provided with a flow control valve and/or, The second hot water pipeline (5) is provided with a flow control valve and/or, The third hot water pipeline (9) is provided with a flow control valve and/or, The fourth cooling water pipeline (11) is provided with a flow control valve and/or, The first cooling water pipeline (6) is provided with a flow control valve and/or, A steam flow regulating valve is arranged at a steam inlet of the absorption heat pump (2).
9. A method for controlling a sludge drying system as claimed in any one of claims 1 to 8, Controlling the water inlet temperature of a hot water inlet of the absorption heat pump (2) to be 60-65 ℃; Preferably, the inlet water temperature of the cooling water inlet of the absorption heat pump (2) is 40-45 ℃.
10. The control method according to claim 9, wherein, Controlling the air inlet temperature of the sludge drying chamber (1) to be 65-80 ℃; preferably, the relative humidity of the inlet air of the sludge drying chamber (1) is controlled to be less than 30%.

Description

Sludge drying system based on absorption heat pump and control method thereof Technical Field The invention belongs to the technical field of sludge drying treatment, and particularly relates to a sludge drying system based on an absorption heat pump and a control method thereof. Background The sludge low-temperature drying adopts a heat pump as one of heat transfer core components, moisture in the air is taken away by cooling the air which comes out of the sludge drying chamber, and meanwhile, the dry and cold air is heated by heat generated by the operation of the heat pump, and the dry and hot air returns to the sludge drying chamber, so that the wet and heat exchange between the air and wet sludge is realized. The absorption heat pump can effectively utilize waste heat as a heat source, avoids the consumption of electric energy by the compressor, and is gradually popularized as a low-energy heat pump. However, the working principle of the absorption heat pump is more complex than that of the compression heat pump, so that the absorption heat pump is very important to combine with the system control logic of low-temperature drying, and the working conditions such as heat pump heating and air temperature of a sludge drying chamber are directly influenced. CN 118684409A discloses a low-grade waste heat driven sludge drying system, which comprises a sludge dryer, an absorption refrigeration cycle system and a second type absorption heat pump cycle system, wherein a fan is connected to a gas outlet of the sludge dryer, a refrigeration evaporator of the sludge dryer, the fan and a heat pump absorber of the second type absorption heat pump cycle system are sequentially and circularly connected to form an air circulation loop, the cold energy of the refrigeration evaporator is from the absorption refrigeration cycle system, the heat energy of the heat pump absorber is from the second type absorption heat pump cycle system, and a waste heat carrier is sequentially cooled step by step through a refrigeration reboiler of the absorption refrigeration cycle system and a heat pump reboiler of the second type absorption heat pump cycle system. The dehumidification of air is realized through the absorption refrigeration cycle, the temperature rise of air is realized through the second type absorption heat pump, and the waste heat carrier sequentially passes through the absorption refrigeration cycle system and the second type absorption heat pump cycle system, so that the grading utilization of the low-grade heat source is realized. Currently, in a sludge drying system adopting an absorption heat pump, the control logic of the absorption heat pump mostly takes the temperature of hot water outlet as a control target, so that the air inlet temperature of a sludge drying chamber is ensured to reach a set temperature. However, the temperature of hot water inlet of the absorption heat pump is higher because of the insufficient heat consumption of sludge drying and the small temperature reduction of hot water outlet of the absorption heat pump. Although the hot water outlet of the absorption heat pump still reaches the set temperature, the stability of the absorption heat pump and the whole sludge drying system is not facilitated, and the waste heat supply amount such as steam is not reduced, so that the COP value of the absorption heat pump is lower. Therefore, aiming at the current situation of a sludge drying system adopting an absorption heat pump, the problems of a system construction and control method need to be solved, and the advantage performance of the absorption heat pump in utilizing a low-grade heat source is exerted. Disclosure of Invention A first object of the present invention is to provide a sludge drying system based on an absorption heat pump, thereby solving at least one of the aforementioned technical problems. The second object of the invention is to provide a control method of the sludge drying system. In order to achieve the first object of the present invention, the following technical solutions are adopted: A sludge drying system based on an absorption heat pump comprises a sludge drying chamber, an absorption heat pump and a closed cooling tower which are communicated through pipelines, The sludge drying chamber comprises a cooling water circulation zone, a hot water circulation zone and a sludge zone, wherein an air inlet and an air outlet of the sludge drying chamber are arranged in the sludge zone and are used for air inlet from the sludge zone to dry and cool and humidify the sludge in the sludge zone, air outlet from the sludge zone and return air to the cooling water circulation zone to dehumidify and cool, and then the sludge is sent to the hot water circulation zone to heat and then air is again inlet to the sludge zone to form air circulation; The system comprises an absorption heat pump, a closed cooling tower, a sludge drying chamber, a first cooling water pipeline, a second cooling wa