Energy-saving sludge reduction system

Abstract

The utility model provides an energy-saving sludge reduction system, which belongs to the field of sludge dewatering and is used for sludge reduction. Water vapor in the drying machine is condensed into a liquid state through the condenser and then releases heat to heat the sludge before dehydration, the viscosity of the heated sludge is reduced, the temperature is increased, the hydrophilicity of polysaccharide and protein components in the sludge is changed, and meanwhile, due to the fact that a conditioner is added into the sludge, the sludge can be recycled. The reaction efficiency of the conditioner and the sludge is improved through heating, the dehydration performance of the sludge is improved through the factors, the dehydration efficiency in the dehydration process is improved, and more water is removed from the sludge through dehydration. Therefore, in the subsequent drying process, water needing to be further removed through drying is reduced, the energy consumption in the drying process is reduced, and the systematic energy consumption of dehydration and drying is reduced.

Description

Technical Field

[0001] The utility model relates to the field of sludge dehydration, in particular to an energy-saving sludge reduction system. Background Art

[0002] Sewage treatment plants produce large amounts of flocculent sludge, a mixture of solids and liquids, during the sewage treatment process. This sludge primarily originates from the sedimentation process during treatment. For every 10,000 tons of treated sewage, approximately 10-20 tons of sludge is produced. This sludge also has a high water content, typically around 90%. This sludge has a high water content, a foul odor, is easily corrupted, and contains heavy metals, as well as toxic chemicals such as organic pollutants and pathogenic microorganisms. This solid waste, when randomly dumped, poses a high risk of secondary pollution. Without effective treatment and disposal, it can easily cause secondary contamination of groundwater and soil, posing a direct threat to environmental safety and public health. Therefore, sludge treatment is essential.

[0003] CN104436796A discloses a sludge dewatering machine that can effectively dewater sewage and sludge and reduce energy consumption. The sludge dewatering machine is mainly composed of the following parts: a housing, a motor, a filtrate recovery tank, a rotating shaft with spiral blades, a dewatering chamber with holes, and a fender. The sludge dewatering machine of the present invention achieves higher dewatering efficiency and reduces energy consumption, which can reduce pollution and save energy. The mechanical dewatering process of sludge can remove 10-30% of the water content and consumes less energy. However, mechanical dewatering alone cannot meet the sludge treatment standards. Therefore, mechanical dewatering and drying are often combined to reduce the sludge.

[0004] CN105712606A discloses an integrated sludge dewatering and drying device and a sludge dewatering and drying method, comprising a sludge screw pump, a screw stack, a sludge dewatering machine, a screw conveyor, an automatic dosing device and a drying device: the sludge screw pump, the screw stack sludge dewatering machine, the screw conveyor and the automatic dosing device of the drying device are connected in sequence through pipelines, and the automatic dosing device is connected to the screw stack sludge dewatering machine: the drying device comprises a heat pump low-temperature dryer, an induced draft fan, a first heat exchanger, a second heat exchanger, a heat pump, a water circulation pump and an electric heater, the heat pump low-temperature dryer, the induced draft fan, the first heat exchanger, the second heat exchanger, the heat pump and the electric heater are connected in sequence through ventilation ducts, and the electric heater is also connected to the heat pump low-temperature dryer through the ventilation duct. The energy consumption of sludge drying process is about 30-300 times that of mechanical dehydration. The energy consumption is extremely high, and a large amount of water vapor is generated during the drying process. In order to meet the requirements of energy conservation and environmental protection, the heat generated during the drying process is generally recovered, but this does not solve the problem of high energy consumption in the drying process.

[0005] To sum up, the sludge precipitated from the sedimentation tank needs to be dehydrated and dried, but the dehydration rate of mechanical dehydration is low and the energy consumption of the drying process is high. Although the heat energy of the drying process can be recovered, the high energy consumption of the drying process is still a problem that needs to be solved urgently. Utility Model Content

[0006] In response to the above problems, the utility model provides an energy-saving sludge reduction system. On the basis of the conventional mechanical dehydration and drying combination, the system adds a condensation system. While ensuring the sludge dehydration rate, the heat energy of the drying process is recovered and reused, saving energy consumption in the drying process.

[0007] The utility model provides an energy-saving sludge reduction system. According to the transportation direction of the sludge, the system includes a dehydration system, a drying system, a condensation system and a recovery system. The dehydration system includes a sludge bin, a conditioning agent bin and a dehydrator. The drying system includes a drying machine and a heating unit. The condensation system includes a condenser. The recovery system includes a recovery bin.

[0008] The condenser includes an indirect condenser or a direct contact condenser.

[0009] Furthermore, the condensation system also includes a sludge heater.

[0010] Furthermore, a water inlet is provided on the top of the sludge bin, a discharge port is provided on the side, and a stirring device is also installed in the sludge bin.

[0011] Furthermore, the dehydrator is provided with a feed port, a discharge port and a separation liquid outlet.

[0012] Furthermore, the dewatering machine includes one of a belt dewatering machine, a centrifugal dewatering machine, a plate and frame filter press, a screw dewatering machine and a laminated spiral sludge dewatering machine.

[0013] Furthermore, the conditioning agent bin is arranged on the pipeline in front of the feed port of the dewatering machine, and the conditioning agent bin is provided with a discharge port. The discharge port of the conditioning agent bin is connected to the pipeline in front of the feed port of the dewatering machine through a feed pipe, and the conditioning agent in the conditioning agent bin enters the dewatering machine together with the sludge in the pipeline in front of the feed port of the dewatering machine.

[0014] Furthermore, a mixer is provided at the connection between the discharge port of the conditioning agent bin and the pipeline in front of the feed port of the dehydrator through the feed pipe to mix the sludge with the conditioning agent in the conditioning agent bin.

[0015] Furthermore, a metering pump is installed on the feed pipe at the outlet of the conditioning agent bin.

[0016] Furthermore, the conditioning agent tank includes one or more of an inorganic conditioning agent tank and an organic conditioning agent tank.

[0017] Furthermore, the sludge heater is provided with a feed port, a discharge port, a circulating water inlet and a circulating water outlet. The feed port of the sludge heater is connected to the discharge port of the sludge bin through a pipeline, and the discharge port of the sludge heater is connected to the feed port of the dehydrator through a pipeline.

[0018] Furthermore, a pump is installed on the pipeline connecting the feed port of the sludge heater and the discharge port of the sludge bin.

[0019] Furthermore, the sludge heater is a shell and tube heat exchanger or a spiral plate heat exchanger.

[0020] Furthermore, the drying machine is provided with a feed port, a discharge port, a steam outlet, a heat medium inlet and a heat medium outlet, and the feed port of the drying machine is connected to the discharge port of the dehydrator through a pipeline or a conveyor.

[0021] Furthermore, the dryer includes one of a thin layer dryer, a rotary disk dryer, a paddle dryer and a spiral dryer.

[0022] Furthermore, the heating unit is provided with a heat medium outlet and a heat medium inlet, the heat medium outlet of the heating unit is connected to the heat medium inlet of the dryer through a pipeline; the heat medium inlet of the heating unit is connected to the heat medium outlet of the dryer through a pipeline.

[0023] Furthermore, the heat medium in the heating unit heats the sludge in the dryer.

[0024] Furthermore, the heating unit includes one of a steam station, a steam boiler or a thermal oil heating furnace.

[0025] Furthermore, the indirect condenser is provided with a steam inlet, a water outlet, a circulating water inlet and a circulating water outlet. The steam inlet of the indirect condenser is connected to the steam outlet of the dryer through a pipe, the water outlet of the indirect condenser is connected to the water inlet of the sludge bin through a pipe, the circulating water inlet of the indirect condenser is connected to the circulating water outlet of the sludge heater through a pipe, and the circulating water outlet of the indirect condenser is connected to the circulating water inlet of the sludge heater through a pipe.

[0026] Furthermore, a pump is installed on the pipe connecting the water outlet of the indirect condenser and the water inlet of the sludge bin, and on the pipe connecting the circulating water inlet of the indirect condenser and the circulating water outlet of the sludge heater.

[0027] Furthermore, the indirect condenser is one or more of a shell and tube condenser or a spiral plate condenser.

[0028] Furthermore, when the hardness of the sludge is less than 150 mg / L, the condenser is an indirect condenser or a direct contact condenser, and the direct contact condenser is provided with a steam inlet, a sludge inlet and a sludge outlet. The steam inlet of the direct contact condenser is connected to the steam outlet of the dryer through a pipeline, the sludge inlet of the direct contact condenser is connected to the discharge port of the sludge bin through a pipeline, the sludge outlet of the direct contact condenser is connected to the feed port of the dehydrator through a pipeline, and the discharge port of the conditioning agent bin is connected to the pipeline connecting the sludge outlet of the direct contact condenser and the feed port of the dehydrator through a feed pipe.

[0029] Furthermore, a mixer is provided at the pipe connecting the discharge port of the conditioning agent bin to the sludge outlet of the direct contact condenser and the feed port of the dehydrator through a feed pipe to mix the sludge with the conditioning agent in the conditioning agent bin.

[0030] Furthermore, the direct contact condenser is also equipped with a spraying device, which sprays the sludge to disperse it into droplets, and the sprayed sludge is heated and mixed with water vapor entering from the steam inlet of the direct contact condenser.

[0031] Furthermore, a pump is installed on the pipeline connecting the sludge inlet of the direct contact condenser and the discharge port of the sludge bin, and on the pipeline connecting the sludge outlet of the direct contact condenser and the feed port of the dehydrator.

[0032] Furthermore, the recovery bin is provided with a feed port, and the feed port of the recovery bin is connected to the discharge port of the drying machine through a pipeline or a conveyor.

[0033] Furthermore, the moisture content of the sludge in the sludge bin is greater than 90%.

[0034] Beneficial effects of the utility model:

[0035] 1. The commonly used sludge reduction method is a combination of mechanical dehydration and drying. However, due to the low dehydration rate in the mechanical dehydration process, the energy consumption required in the drying process is high, and the heat energy of the evaporated water vapor generated in the drying process is wasted. The utility model recycles the heat energy of the evaporated water vapor in the drying process and heats the sludge first, thereby improving the dehydration rate of the dehydrator in the system, thereby reducing the energy consumption of the dryer. The system of the utility model is applicable to general dehydrators and dryers sold on the market and is widely used. The utility model can select an indirect or direct condenser to condense the steam in the dryer according to the hardness of the sludge, and recycle the heat energy in the drying process, saving energy and reducing the system performance consumption of the dehydration and drying processes.

[0036] 2. The condenser in the present invention can be an indirect or direct condenser to condense the steam in the dryer. The indirect condenser can be used in all sludge reduction processes without limitation to the hardness or other properties of the sludge. When the hardness of the sludge is less than 150 mg / L, an indirect condenser or a direct contact condenser can be selected to recycle the heat energy in the drying process. When the hardness is too high, the sludge in the direct contact condenser may precipitate with the condensate, thereby clogging the circuit.

[0037] 3. The evaporated water vapor in the dryer of the utility model is condensed into liquid through the condenser and releases heat energy to heat the sludge before dehydration. The viscosity of the heated sludge is reduced, and the increase in temperature changes the hydrophilicity of the polysaccharide and protein components in the sludge. At the same time, since a conditioner is added to the sludge, heating improves the reaction efficiency of the conditioner and the sludge. These factors improve the dehydration performance of the sludge, improve the dehydration efficiency during the dehydration process, and remove more water from the sludge through dehydration. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a schematic structural diagram of the energy-saving sludge reduction system described in Example 1;

[0039] Figure 2 This is a schematic structural diagram of the energy-saving sludge reduction system described in Example 2;

[0040] Figure 3 This is a schematic structural diagram of the energy-saving sludge reduction system described in Comparative Example 1;

[0041] The numbers in the figure are 1, sludge bin; 2a, inorganic conditioning agent bin; 2b, organic conditioning agent bin; 3, sludge heater; 4, dehydrator; 5, dryer; 6, heating unit; 7, recovery bin; 8, direct contact condenser; 9, indirect condenser. DETAILED DESCRIPTION

[0042] The utility model is described in detail below with reference to the embodiments:

[0043] The utility model provides an energy-saving sludge reduction system, which recovers the evaporated steam in the dryer and then passes the recovered heat energy into the sludge to heat the sludge, thereby greatly reducing the energy consumption of the dryer.

[0044] Example 1

[0045] This embodiment provides an energy-saving sludge reduction system. The system includes a dehydration system, a drying system, a condensation system, and a recovery system according to the sludge transportation direction. The dehydration system includes a sludge bin 1, a conditioning agent bin, and a dehydrator 4. The drying system includes a drying machine 5 and a heating unit 6. The condensation system includes a condenser. The recovery system includes a recovery bin 7.

[0046] The condenser includes an indirect condenser 9 .

[0047] In this embodiment, the condensation system further includes a sludge heater 3;

[0048] The sludge bin 1 is provided with a water inlet on the top and a discharge port on the side, and a stirring device is also installed in the sludge bin 1;

[0049] The dehydrator 4 is provided with a feed port, a discharge port and a separation liquid outlet; the dehydrator 4 dehydrates the sludge mechanically; the dehydrator 4 is a centrifugal dehydrator;

[0050] The conditioning agent bin is arranged on the pipeline in front of the feed port of the dewatering machine 4, and the conditioning agent bin is provided with a discharge port. The discharge port of the conditioning agent bin is connected to the pipeline in front of the feed port of the dewatering machine 4 through a feed pipe, and the conditioning agent in the conditioning agent bin enters the dewatering machine 4 together with the sludge in the pipeline in front of the feed port of the dewatering machine 4; a mixer is provided at the connection between the discharge port of the conditioning agent bin and the pipeline in front of the feed port of the dewatering machine 4 through the feed pipe, to mix the sludge with the conditioning agent in the conditioning agent bin, and a metering pump is installed on the feed pipe at the discharge port of the conditioning agent bin;

[0051] The conditioning agent bin includes an organic conditioning agent bin 2b;

[0052] The organic conditioning agent tank 2b includes an organic conditioning agent, the mass ratio of the organic conditioning agent to the solids in the sludge is 7:1000, and the organic conditioning agent is polyacrylamide (PAM);

[0053] The sludge heater 3 is provided with a feed port, a discharge port, a circulating water inlet and a circulating water outlet. The feed port of the sludge heater 3 is connected to the discharge port of the sludge bin 1 through a pipeline, and the discharge port of the sludge heater 3 is connected to the feed port of the dehydrator 4 through a pipeline; a pump is also installed on the pipeline connecting the feed port of the sludge heater 3 and the discharge port of the sludge bin 1; the sludge heater is a shell and tube heat exchanger;

[0054] The drying machine 5 is provided with a feed port, a discharge port, a steam outlet, a heat medium inlet and a heat medium outlet. The feed port of the drying machine 5 is connected to the discharge port of the dehydrator 4 through a pipeline; the drying machine 5 is a thin layer drying machine;

[0055] The heating unit 6 is provided with a heat medium outlet and a heat medium inlet. The heat medium outlet of the heating unit 6 is connected to the heat medium inlet of the dryer 5 via a pipeline; the heat medium inlet of the heating unit 6 is connected to the heat medium outlet of the dryer 5 via a pipeline; the heat medium in the heating unit 6 heats the sludge in the dryer 5; the heating unit 6 is a steam boiler;

[0056] The indirect condenser 9 is provided with a steam inlet, a water outlet, a circulating water inlet and a circulating water outlet. The steam inlet of the indirect condenser 9 is connected to the steam outlet of the dryer 5 through a pipeline, the water outlet of the indirect condenser 9 is connected to the water inlet of the sludge bin 1 through a pipeline, the circulating water inlet of the indirect condenser 9 is connected to the circulating water outlet of the sludge heater 3 through a pipeline, and the circulating water outlet of the indirect condenser 9 is connected to the circulating water inlet of the sludge heater 3 through a pipeline.

[0057] A pump is also installed on the pipe connecting the water outlet of the indirect condenser 9 and the water inlet of the sludge bin 1, as well as on the pipe connecting the circulating water inlet of the indirect condenser 9 and the circulating water outlet of the sludge heater 3; the indirect condenser 9 is a shell and tube condenser;

[0058] The recovery bin 7 is provided with a feed port, and the feed port of the recovery bin 7 is connected to the discharge port of the drying machine 5 through a pipeline.

[0059] In this embodiment, the method for dehydrating and drying sludge using the energy-saving sludge reduction system is as follows:

[0060] First, the sludge in the sludge bin 1 is pumped to the sludge heater 3, and then enters the dehydrator 4 through the sludge heater 3 for mechanical dehydration. Before entering the dehydrator 4, the organic conditioning agent in the organic conditioning agent bin 2b is added to the transported sludge. The removed water is discharged from the separation liquid outlet of the dehydrator 4. The dehydrated sludge enters the drying machine 5 from the dehydrator 4. At this time, no water vapor is generated in the system.

[0061] When the dehydrated sludge enters the dryer 5, the heat supply unit 6 introduces heat medium into the dryer 5, and the heat medium heats and dries the dehydrated sludge in the dryer 5. The heated heat medium returns to the heat supply unit 6 from the dryer 5 for circulation. The dehydrated sludge is dried in the dryer 5 to generate water vapor, which is condensed into liquid condensed water in the indirect condenser 9. The condensed water enters the sludge bin 1 through a pump and is mixed with the undehydrated sludge. The mixed sludge is transported to the sludge heater 3 through a pump for heating. The heated sludge enters the dehydrator 4 for further mechanical dehydration. The dehydrated sludge enters the dryer 5 from the dehydrator 4 for further drying to generate water vapor. The water vapor continues to enter the indirect condenser 9 to heat the circulating water and enters the sludge bin 1 for circulation. The sludge dried in the dryer 5 enters the recovery bin 7 for recovery.

[0062] Circulating water is passed between the circulating water inlet and outlet of the sludge heater 3 and the circulating water inlet and outlet of the indirect condenser 9. The circulating water is heated by the heat energy in the water vapor condensation process in the indirect condenser 9 and then passes into the sludge heater 3, heats the sludge in the sludge heater 3, and then is pumped back to the indirect condenser 9 by the sludge heater 3 for heating.

[0063] In this embodiment, the initial temperature of the sludge is 15°C, the sludge hardness is 150 mg / L, the water vapor temperature in the dryer 5 is 100°C, the temperature of the liquid after condensation by the indirect condenser 9 is 85°C, the temperature of the circulating water between the circulating water outlet of the indirect condenser 9 and the circulating water inlet of the sludge heater 3 is 80°C, the temperature of the sludge transported by the sludge heater 3 to the dehydrator 4 is 65°C, the mass of the sludge in the sludge bin 1 is 100t, and the moisture content is 95%, the mass of the sludge after dehydration by the dehydrator 4 is 20t, and the moisture content is 75%, the mass of the sludge after drying by the dryer 5 is 8.3t, and the moisture content is 40%, the energy consumption of the dehydrator 4 is 16kWh, the energy consumption of the dryer 5 is 375kWh, and the system energy consumption of dehydration and drying is 391kWh.

[0064] Example 2

[0065] This embodiment provides an energy-saving sludge reduction system. The system includes a dehydration system, a drying system, a condensation system, and a recovery system according to the sludge transportation direction. The dehydration system includes a sludge bin 1, a conditioning agent bin, and a dehydrator 4. The drying system includes a drying machine 5 and a heating unit 6. The condensation system includes a condenser. The recovery system includes a recovery bin 7.

[0066] The condenser comprises a direct contact condenser 8 .

[0067] In this embodiment, the sludge bin 1 is provided with a water inlet on the top and a discharge port on the side, and the sludge bin 1 is also equipped with a stirring device;

[0068] The dehydrator 4 is provided with a feed port, a discharge port and a separation liquid outlet; the dehydrator 4 dehydrates the sludge mechanically; the dehydrator 4 is a centrifugal dehydrator;

[0069] The conditioning agent bin is arranged on the pipeline in front of the feed port of the dewatering machine 4, and the conditioning agent bin is provided with a discharge port. The discharge port of the conditioning agent bin is connected to the pipeline in front of the feed port of the dewatering machine 4 through a feed pipe, and the conditioning agent in the conditioning agent bin enters the dewatering machine 4 together with the sludge in the pipeline in front of the feed port of the dewatering machine 4; a mixer is provided at the connection between the discharge port of the conditioning agent bin and the pipeline in front of the feed port of the dewatering machine 4 through the feed pipe, to mix the sludge with the conditioning agent in the conditioning agent bin, and a metering pump is installed on the feed pipe at the discharge port of the conditioning agent bin;

[0070] The conditioning agent bin includes an organic conditioning agent bin 2b;

[0071] The organic conditioning agent tank 2b includes an organic conditioning agent, the mass ratio of the organic conditioning agent to the solids in the sludge is 7:1000, and the organic conditioning agent is polyacrylamide (PAM);

[0072] The sludge heater 3 is provided with a feed port, a discharge port, a circulating water inlet and a circulating water outlet. The feed port of the sludge heater 3 is connected to the discharge port of the sludge bin 1 through a pipeline, and the discharge port of the sludge heater 3 is connected to the feed port of the dehydrator 4 through a pipeline; a pump is also installed on the pipeline connecting the feed port of the sludge heater 3 and the discharge port of the sludge bin 1; the sludge heater is a shell and tube heat exchanger;

[0073] The drying machine 5 is provided with a feed port, a discharge port, a steam outlet, a heat medium inlet and a heat medium outlet. The feed port of the drying machine 5 is connected to the discharge port of the dehydrator 4 through a pipeline; the drying machine 5 is a thin layer drying machine;

[0074] The heating unit 6 is provided with a heat medium outlet and a heat medium inlet. The heat medium outlet of the heating unit 6 is connected to the heat medium inlet of the dryer 5 via a pipeline; the heat medium inlet of the heating unit 6 is connected to the heat medium outlet of the dryer 5 via a pipeline; the heat medium in the heating unit 6 heats the sludge in the dryer 5; the heating unit 6 is a natural gas boiler;

[0075] The direct contact condenser 8 is provided with a steam inlet, a sludge inlet and a sludge outlet. The steam inlet of the direct contact condenser 8 is connected to the steam outlet of the dryer 5 through a pipeline. The sludge inlet of the direct contact condenser 8 is connected to the discharge port of the sludge bin 1 through a pipeline. The sludge outlet of the direct contact condenser 8 is connected to the feed port of the dehydrator 4 through a pipeline. The pipeline connecting the sludge outlet of the direct contact condenser 8 to the feed port of the dehydrator 4 is connected to the discharge port of the conditioning agent bin through a feed pipe.

[0076] A mixer is provided at the pipe connecting the discharge port of the conditioning agent bin to the sludge outlet of the direct contact condenser 8 and the feed port of the dehydrator 4 through a feed pipe to mix the sludge with the conditioning agent in the conditioning agent bin;

[0077] The direct contact condenser 8 is also equipped with a spraying device, which sprays the sludge into droplets, and the sprayed sludge is heated and mixed with the water vapor entering from the steam inlet of the direct contact condenser 8;

[0078] A pump is also installed on the pipe connecting the sludge inlet of the direct contact condenser 8 and the discharge port of the sludge bin 1, and on the pipe connecting the sludge outlet of the direct contact condenser 8 and the feed port of the dehydrator 4;

[0079] The recovery bin 7 is provided with a feed port, and the feed port of the recovery bin 7 is connected to the discharge port of the drying machine 5 through a pipeline.

[0080] In this embodiment, the method for dehydrating and drying sludge using the energy-saving sludge reduction system is as follows:

[0081] First, the sludge in the sludge bin 1 is pumped into the direct contact condenser 8, sprayed by the spraying device in the direct contact condenser 8, and then pumped into the dehydrator 4 for mechanical dehydration. Before entering the dehydrator 4, the organic conditioning agent in the organic conditioning agent bin 2b is added to the transported sludge. The removed water is discharged from the separation liquid outlet of the dehydrator 4. The dehydrated sludge enters the drying machine 5 from the dehydrator 4. At this time, no water vapor is generated in the system.

[0082] When the dehydrated sludge enters the dryer 5, the heat supply unit 6 introduces heat medium into the dryer 5, and the heat medium heats and dries the dehydrated sludge in the dryer 5. The heated heat medium returns to the heat supply unit 6 from the dryer 5 for circulation. The dehydrated sludge is dried in the dryer 5 to produce water vapor, which is condensed into liquid condensed water in the direct contact condenser 8 and mixed with the sludge sprayed in the direct contact condenser 8 and heated by the heat medium. The mixed and heated sludge is discharged from the direct contact condenser 8 through the The sludge is pumped to the dehydrator 4, and during the transportation process, an organic conditioner is added through the organic conditioner bin 2b. The sludge is mechanically dehydrated in the dehydrator 4, and the removed water is discharged from the separation liquid outlet of the dehydrator 4. The dehydrated sludge enters the dryer 5 from the dehydrator 4. The sludge is heated by the heat medium provided by the heating unit 6 in the dryer 5 to generate water vapor. The water vapor continues to enter the direct contact condenser 8 to mix with the undehydrated sludge and circulate. The sludge dried in the dryer 5 enters the recovery bin 7 for recovery.

[0083] In this embodiment, the initial sludge temperature is 15°C, the sludge hardness is 100 mg / L, the evaporated water vapor temperature in the dryer 5 is 100°C, the temperature of the liquid after condensation by the direct contact condenser 8 is 60°C, the temperature of the sludge transported to the dehydrator 4 is 60°C, the mass of the sludge in the sludge bin 1 is 100t, and the moisture content is 95%, the mass of the sludge after dehydration by the dehydrator 4 is 20.4t, and the moisture content is 75.5%, the mass of the sludge after drying by the dryer 5 is 8.3t, and the moisture content is 40%, the energy consumption of the dehydrator 4 is 16kWh, the energy consumption of the dryer 5 is 390kWh, and the system energy consumption of dehydration and drying is 406kWh.

[0084] Comparative Example 1

[0085] This comparative example provides a sludge dehydration and drying system. According to the sludge transportation direction, the system includes a sludge bin 1, an organic conditioning agent bin 2b, a dehydrator 4, a drying machine 5, a heating unit 6 and a recovery bin 7.

[0086] In this comparative example, the sludge bin 1 is provided with a water inlet on the top and a discharge port on the side, and the sludge bin 1 is also equipped with a stirring device;

[0087] The dehydrator 4 is provided with a feed port, a discharge port and a separation liquid outlet; the dehydrator 4 dehydrates the sludge mechanically; the dehydrator 4 is a centrifugal dehydrator; the dehydrator 4 dehydrates the sludge mechanically;

[0088] The organic conditioning agent bin 2b is arranged on the pipeline in front of the feed port of the dehydrator 4, and the organic conditioning agent bin 2b is provided with a discharge port. The discharge port of the organic conditioning agent bin 2b is connected to the pipeline in front of the feed port of the dehydrator 4 through a feed pipe, and the organic conditioning agent in the organic conditioning agent bin 2b enters the dehydrator 4 together with the sludge in the pipeline in front of the feed port of the dehydrator 4; a mixer is provided at the connection between the discharge port of the organic conditioning agent bin 2b and the pipeline in front of the feed port of the dehydrator 4 through the feed pipe, to mix the sludge with the organic conditioning agent in the organic conditioning agent bin 2b, and a metering pump is installed on the feed pipe at the discharge port of the organic conditioning agent bin 2b;

[0089] The organic conditioning agent tank 2b includes an organic conditioning agent, the mass ratio of the organic conditioning agent to the solids in the sludge is 7:1000, and the organic conditioning agent is polyacrylamide (PAM);

[0090] The dryer 5 is provided with a feed inlet, a discharge port, a steam outlet, a heat medium inlet and a heat medium outlet. The feed inlet of the dryer 5 is connected to the discharge port of the dehydrator 4 through a pipeline; the dryer 5 is a thin layer dryer; the air outlet of the dryer 5 is connected to the exhaust gas treatment system;

[0091] The heating unit 6 is provided with a heat medium outlet and a heat medium inlet. The heat medium outlet of the heating unit 6 is connected to the heat medium inlet of the dryer 5 via a pipeline; the heat medium inlet of the heating unit 6 is connected to the heat medium outlet of the dryer 5 via a pipeline; the heat medium in the heating unit 6 heats the sludge in the dryer 5; the heating unit 6 is a natural gas boiler;

[0092] The recovery bin 7 is provided with a feed port, and the feed port of the recovery bin 7 is connected to the discharge port of the drying machine 5 through a pipeline.

[0093] This comparative example also provides a dehydration and drying method using the sludge dehydration and drying system, and the method is specifically as follows:

[0094] The organic conditioner in the organic conditioner bin 2b enters the feed port of the sludge bin 1 through the feed pipe from the discharge port of the organic conditioner bin 2b, and is stirred and mixed with the sludge in the sludge bin 1. The mixed sludge enters the dewatering machine 4 from the feed port through the conveyor for dehydration. The dehydrated sludge enters the feed port of the dryer 5 from the discharge port of the dewatering machine 4 through the conveyor. In the dryer 5, a heat medium is provided to the dryer 5 through the heating unit 6 to heat and dry the sludge in the dryer 5. The water vapor generated during the drying process is introduced into the exhaust gas treatment system. The dried sludge enters the recovery bin 7 from the discharge port of the dryer 5 through the conveyor and the feed port of the recovery bin 7 for recovery.

[0095] In this comparative example, the initial temperature of the sludge is 15°C, the evaporation temperature of the water vapor in the dryer 5 is 100°C, the mass of the sludge in the sludge bin 1 is 100t, and the moisture content is 95%. The mass of the sludge after dehydration by the dehydrator 4 is 25t, and the moisture content is 80%. The mass of the sludge after drying by the dryer 5 is 8.3t, and the moisture content is 40%. The energy consumption of the dehydrator 4 is 16kWh, the energy consumption of the dryer 5 is 565kWh, and the system energy consumption of dehydration and drying is 581kWh.

[0096] Comparative Example 2

[0097] This comparative example provides a sludge dehydration and drying system. According to the sludge transportation direction, the system includes a sludge bin 1, an organic conditioning agent bin 2b, a dehydrator 4, a drying machine 5 and a recovery bin 7.

[0098] In this comparative example, the sludge bin 1 is provided with a water inlet on the top and a discharge port on the side, and the sludge bin 1 is also equipped with a stirring device;

[0099] The dehydrator 4 is provided with a feed port, a discharge port and a separation liquid outlet; the dehydrator 4 dehydrates the sludge mechanically; the dehydrator 4 is a centrifugal dehydrator; the dehydrator 4 dehydrates the sludge mechanically;

[0100] The organic conditioning agent bin 2b is arranged on the pipeline in front of the feed port of the dehydrator 4, and the organic conditioning agent bin 2b is provided with a discharge port. The discharge port of the organic conditioning agent bin 2b is connected to the pipeline in front of the feed port of the dehydrator 4 through a feed pipe, and the organic conditioning agent in the organic conditioning agent bin 2b enters the dehydrator 4 together with the sludge in the pipeline in front of the feed port of the dehydrator 4; a mixer is provided at the connection between the discharge port of the organic conditioning agent bin 2b and the pipeline in front of the feed port of the dehydrator 4 through the feed pipe, to mix the sludge with the organic conditioning agent in the organic conditioning agent bin 2b, and a metering pump is installed on the feed pipe at the discharge port of the organic conditioning agent bin 2b;

[0101] The organic conditioning agent tank 2b includes an organic conditioning agent, the mass ratio of the organic conditioning agent to the solids in the sludge is 7:1000, and the organic conditioning agent is polyacrylamide (PAM);

[0102] The dryer 5 is provided with a feed inlet, a discharge port, a steam outlet, a heat medium inlet and a heat medium outlet. The feed inlet of the dryer 5 is connected to the discharge port of the dehydrator 4 through a pipeline; the dryer 5 is a thin layer dryer; the air outlet of the dryer 5 is connected to the exhaust gas treatment system;

[0103] The heating unit 6 is provided with a heat medium outlet and a heat medium inlet. The heat medium outlet of the heating unit 6 is connected to the heat medium inlet of the dryer 5 via a pipeline; the heat medium inlet of the heating unit 6 is connected to the heat medium outlet of the dryer 5 via a pipeline; the heat medium in the heating unit 6 heats the sludge in the dryer 5; the heating unit 6 is a natural gas boiler;

[0104] The recovery bin 7 is provided with a feed port, and the feed port of the recovery bin 7 is connected to the discharge port of the drying machine 5 through a pipeline.

[0105] This comparative example also provides a dehydration and drying method using the sludge dehydration and drying system, and the method is specifically as follows:

[0106] The organic conditioner in the organic conditioner bin 2b enters the feed port of the sludge bin 1 through the feed pipe from the discharge port of the organic conditioner bin 2b, and is stirred and mixed with the sludge in the sludge bin 1. The mixed sludge enters the dewatering machine 4 from the feed port through the conveyor for dehydration. The dehydrated sludge enters the feed port of the dryer 5 from the discharge port of the dewatering machine 4 through the conveyor. In the dryer 5, a heat medium is provided to the dryer 5 through the heating unit 6 to heat and dry the sludge in the dryer 5. The water vapor generated during the drying process is introduced into the exhaust gas treatment system. The dried sludge enters the recovery bin 7 from the discharge port of the dryer 5 through the conveyor and the feed port of the recovery bin 7 for recovery.

[0107] In this comparative example, the water vapor temperature in the dryer 5 is 100°C, the mass of the sludge in the sludge bin 1 is 100t, and the moisture content is 95%. The mass of the sludge after dehydration by the dehydrator 4 is 27.8t, and the moisture content is 82%. The mass of the sludge after drying by the dryer 5 is 8.3t, and the moisture content is 40%. The energy consumption of the dehydrator 4 is 5kWh, the energy consumption of the dryer 5 is 660kWh, and the system energy consumption of dehydration and drying is 665kWh.

[0108] Table 1

[0109]

[0110] As shown in Table 1, the sludge is dehydrated and dried by the system in Examples 1-2 of the present invention, and the heat energy in the drying process is recovered and reused to heat the sludge, thereby greatly reducing the energy consumption of the drying process.

[0111] Based on the above, it can be seen that the energy-saving sludge reduction system described in the utility model has a wide range of applications, low cost, and high market prospects.

[0112] The above description is merely a preferred embodiment of the present invention and does not constitute any other limitation to the present invention. Any modification or equivalent variation based on the technical essence of the present invention shall still fall within the scope of protection claimed by the present invention.

Claims

1. An energy-saving sludge reduction system, characterized in that: The system comprises a dehydration system, a drying system, a condensation system and a recovery system, wherein the dehydration system comprises a sludge bin (1), a conditioning agent bin and a dehydrator (4), the drying system comprises a drying machine (5) and a heating unit (6), the condensation system comprises a condenser, and the recovery system comprises a recovery bin (7); The condenser comprises an indirect condenser (9) or a direct contact condenser (8).

2. The energy-saving sludge reduction system according to claim 1 is characterized in that: The condensation system also includes a sludge heater (3).

3. The energy-saving sludge reduction system according to claim 1 is characterized in that: The sludge bin (1) is provided with a water inlet on the top and a discharge port on the side. The sludge bin (1) is also provided with a stirring device.

4. The energy-saving sludge reduction system according to claim 2 is characterized in that: The sludge heater (3) is provided with a feed port, a discharge port, a circulating water inlet and a circulating water outlet. The feed port of the sludge heater (3) is connected to the discharge port of the sludge bin (1) through a pipeline, and the discharge port of the sludge heater (3) is connected to the feed port of the dehydrator (4) through a pipeline.

5. The energy-saving sludge reduction system according to claim 4 is characterized in that: A pump is also installed on the pipeline connecting the feed port of the sludge heater (3) and the discharge port of the sludge bin (1).

6. The energy-saving sludge reduction system according to claim 1, characterized in that: The drying machine (5) is provided with a feed port, a discharge port, a steam outlet, a heat medium inlet, and a heat medium outlet. The feed port of the drying machine (5) is connected to the discharge port of the dehydrator (4) through a pipeline.

7. The energy-saving sludge reduction system according to claim 1, characterized in that: The heating unit (6) is provided with a heat medium outlet and a heat medium inlet. The heat medium outlet of the heating unit (6) is connected to the heat medium inlet of the drying machine (5) through a pipeline; the heat medium inlet of the heating unit (6) is connected to the heat medium outlet of the drying machine (5) through a pipeline.

8. The energy-saving sludge reduction system according to claim 2, characterized in that: The indirect condenser (9) is provided with a steam inlet, a water outlet, a circulating water inlet and a circulating water outlet. The steam inlet of the indirect condenser (9) is connected to the steam outlet of the dryer (5) through a pipeline, the water outlet of the indirect condenser (9) is connected to the water inlet of the sludge bin (1) through a pipeline, the circulating water inlet of the indirect condenser (9) is connected to the circulating water outlet of the sludge heater (3) through a pipeline, and the circulating water outlet of the indirect condenser (9) is connected to the circulating water inlet of the sludge heater (3) through a pipeline.

9. The energy-saving sludge reduction system according to claim 2, characterized in that: A pump is also installed on the pipe connecting the water outlet of the indirect condenser (9) and the water inlet of the sludge bin (1), and on the pipe connecting the circulating water inlet of the indirect condenser (9) and the circulating water outlet of the sludge heater (3).

10. The energy-saving sludge reduction system according to claim 1, characterized in that: The recovery bin (7) is provided with a feed port, and the feed port of the recovery bin (7) is connected to the discharge port of the drying machine (5) via a pipeline or a conveyor.

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