Steam two-stage sludge drying system for thermal power plant

Abstract

The utility model provides a steam secondary sludge drying system of thermal power plant, including drying machine, water mixer, drying tower, heat exchanger, drying machine's exhaust end is connected with heat exchanger through integrated dust catcher, drying machine's hot water export end is connected with water mixer, water mixer's water outlet is connected with drying tower, drying tower's water outlet is connected with heat exchanger's second water inlet, heat exchanger's water outlet is connected with water mixer, and one end of heat exchanger is connected with waste gas treatment system through exhaust steam fan. The system can effectively recycle the exhaust steam heat energy generated by sludge heat drying, reduces the sludge heat drying steam consumption, recycles the heat of the steam changed into hot water after sludge heat drying technology drying, reduces the circulating water consumption. Very good reduction sludge disposal cost. The whole system is negative pressure operation, and the waste gas does not leak, is favorable to environmental protection, is not easy to cause pollution. Conform to the guiding direction of national energy saving and emission reduction, waste heat recycling and other policies, can long -term development.

Description

Technical Field

[0001] This utility model belongs to the field of sludge treatment technology, specifically relating to a two-stage steam sludge drying system for thermal power plants. Background Technology

[0002] Secondary sludge from thermal power plants mainly refers to solid waste with high water content generated during the production process of thermal power plants. It primarily originates from wastewater treatment processes, including ash flushing wastewater (accounting for approximately 50% of the total wastewater, containing high concentrations of suspended solids), desulfurization wastewater (containing pollutants such as sulfites and heavy metals), industrial wastewater (containing oils, acids, and alkalis), and domestic sewage (containing organic pollutants). These wastes are typically utilized through thermal treatment processes such as sludge drying and incineration. For example, a dryer can be used to heat the wet sludge using steam, hot oil, or electricity. The resulting dry sludge is then disposed of independently or in conjunction with other treatments. The exhaust steam is treated by a dust collector and condenser, condensate is sent to the wastewater treatment system, and the exhaust gas is sent to the exhaust gas treatment system or fed into the boiler as primary and secondary air for combustion. However, in this method, the exhaust gas is directly cooled by circulating water, resulting in ineffective heat utilization. Furthermore, the steam used in the drying process is typically converted into hot water and then directly discharged, further hindering heat utilization and leading to energy waste. Utility Model Content

[0003] To address the shortcomings of existing technologies, this utility model provides a steam-based secondary sludge drying system for thermal power plants.

[0004] The objective of this utility model is achieved through the following technical solution: A secondary steam sludge drying system for a thermal power plant includes a dryer, a mixer, a drying tower, and a heat exchanger. The exhaust steam end of the dryer is connected to the heat exchanger via an integrated dust collector. The hot water outlet end of the dryer is connected to the mixer. The water outlet end of the mixer is connected to the drying tower. The water outlet end of the drying tower is connected to the second water inlet end of the heat exchanger. The water outlet end of the heat exchanger is connected to the mixer. One end of the heat exchanger is connected to a waste gas treatment system via an exhaust steam fan.

[0005] Preferably, an electric valve assembly is provided between the heat exchanger and the integrated dust collector.

[0006] Preferably, the mixer is provided with a steam end, and a level gauge is installed inside the mixer. The level gauge is electrically connected to a condensate valve connected to the outlet end of the drying tower.

[0007] Preferably, the upper end of the drying tower is provided with a mud inlet, and one side of the mud inlet of the drying tower is connected to the exhaust steam treatment system through a pipeline.

[0008] Preferably, the drying tower is connected to a heat exchanger via a hot water circulation pump.

[0009] Preferably, a sludge drying coil is provided at the bottom of the drying tower.

[0010] The beneficial effects of this invention are as follows: This system can effectively recover and utilize the waste steam heat energy generated during sludge thermal drying, reducing the steam consumption for sludge thermal drying. It also recovers the heat from converting the steam used in sludge thermal drying into hot water, reducing the consumption of circulating water. This significantly reduces sludge disposal costs. The entire system operates under negative pressure, preventing waste gas leakage, which is beneficial to environmental protection and less likely to cause pollution. It aligns with national policies on energy conservation, emission reduction, and waste heat reuse, and has long-term development potential. Attached Figure Description

[0011] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0012] Figure 1 : A schematic diagram of the structure of this utility model. Detailed Implementation

[0013] This utility model discloses a secondary steam sludge drying system for thermal power plants, combined with... Figure 1 As shown, the system includes a dryer 1, a water mixer 4, a drying tower 5, and a heat exchanger 3.

[0014] The dryer 1 can be a disc dryer, a thin-layer dryer, or a paddle dryer, etc. The upper end of the dryer 1 has a sludge inlet 11, and the lower end of the dryer 1 has a sludge outlet 12. To ensure the vacuum level of the system, the sludge outlet of the dryer 1 is equipped with a double-flip airlock.

[0015] The upper end of the dryer 1 is provided with a waste steam end, which is connected to the heat exchanger 3 through an integrated dust collector 2. For better automated control, an electric valve assembly 23 is provided between the heat exchanger 3 and the integrated dust collector 2. Steam inlets and hot water outlets are respectively provided on the two end sides of the dryer 1.

[0016] The hot water outlet 13 is connected to the mixer 4. To ensure timely heat replenishment in case of insufficient secondary heat, the mixer 4 is equipped with a steam end 41, which is connected to an external steam device. The mixer 4 also contains a level gauge, which is electrically connected to a steam trap 6 connected to the outlet of the drying tower.

[0017] The outlet of the mixing device 4 is connected to the drying tower 5. A sludge drying coil is installed at the bottom of the drying tower 5. A sludge inlet 51 is installed at the top of the drying tower 5, and one side of the sludge inlet of the drying tower 5 is connected to the exhaust steam treatment system through a pipeline.

[0018] The outlet of the drying tower 5 is connected to the second inlet 32 ​​of the heat exchanger 3. To provide stable circulation power, the outlet of the drying tower 5 is connected to the second inlet of the heat exchanger 3 via a hot water circulation pump 67. The first outlet 31 of the heat exchanger 3 is connected to the first heat exchange end of the mixing device 4. One end of the heat exchanger 3 is connected to the waste gas treatment system via a waste steam blower 7.

[0019] During operation, the wet sludge to be treated enters through the sludge inlet of the dryer 1. Steam introduced through the steam inlet of the dryer 1 heats the wet sludge inside the dryer. The resulting dry sludge first passes through a double-flip airlock (maintaining vacuum) and is then transported through the sludge outlet 12 for individual or co-processing. The generated exhaust steam undergoes dust removal through the integrated dust collector 2, and the exhaust steam flow is regulated by the electric valve group 23. After heat exchange and condensation of wastewater through the heat exchanger 3, the exhaust steam is sent to the exhaust steam blower 7 and enters the waste gas treatment system.

[0020] After the wet sludge is fed into the drying tower 5 through the sludge inlet of the drying tower 5, the sludge drying coil at the bottom of the drying tower heats and dries the wet sludge. The dried semi-dry sludge is then discharged from the sludge inlet of the drying tower, and the generated exhaust steam enters the exhaust steam treatment system.

[0021] The steam used for drying is converted into hot water after the wet sludge is dried in the dryer. The hot water enters the mixing tank 4 from the hot water outlet 13 for storage and then enters the drying tower for heat utilization. Since the mixing tank is connected to a steam end 41, it is easy to replenish steam in time when the secondary heat is insufficient for the use of the drying tower. Under the pressure of the hot water circulation pump 67, the water that enters the drying coil to heat the wet sludge is circulated to the heat exchanger 3 for reheating. The low-temperature water entering the heat exchanger absorbs the phase change heat of the exhaust steam and then returns to the mixing tank 4, thus achieving a continuous cycle.

[0022] The mixing valve 4 is equipped with a level gauge, which can control the opening and closing of the steam trap 6. When the liquid level reaches the set height, the steam trap 6 opens to drain the water. When the liquid level drops below the set height, the steam trap 6 closes.

[0023] Finally, it should be noted that the terms "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used solely for the convenience of describing this utility model and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0024] Furthermore, the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it; although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A steam-based secondary sludge drying system for thermal power plants, characterized in that: The system includes a dryer (1), a water mixer (4), a drying tower (5), and a heat exchanger (3). The exhaust steam end of the dryer (1) is connected to the heat exchanger (3) through an integrated dust collector (2). The hot water outlet end (13) of the dryer (1) is connected to the water mixer (4). The water outlet end of the water mixer (4) is connected to the drying tower (5). The water outlet end of the drying tower (5) is connected to the second water inlet end (32) of the heat exchanger (3). The water outlet end (31) of the heat exchanger (3) is connected to the water mixer. One end of the heat exchanger (3) is connected to the waste gas treatment system through an exhaust steam fan (7).

2. The secondary steam sludge drying system for thermal power plants as described in claim 1, characterized in that: An electric valve assembly (23) is provided between the heat exchanger (3) and the integrated dust collector (2).

3. The secondary steam sludge drying system for thermal power plants as described in claim 2, characterized in that: The mixer (4) is provided with a steam end (41), and a level gauge is provided inside the mixer (4). The level gauge is electrically connected to a drain valve (6) connected to the outlet of the drying tower.

4. The secondary steam sludge drying system for thermal power plants as described in claim 3, characterized in that: The drying tower (5) is provided with a mud inlet at the upper end, and the mud inlet side of the drying tower (5) is connected to the exhaust steam treatment system through a pipeline.

5. The secondary steam sludge drying system for thermal power plants as described in claim 4, characterized in that: The drying tower (5) is connected to the heat exchanger (3) via a hot water circulation pump (67).

6. The secondary steam sludge drying system for thermal power plants as described in claim 5, characterized in that: The bottom of the drying tower (5) is equipped with a sludge drying coil.

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