Drying machine steam supply device and process based on drying tail gas waste heat

Abstract

The invention discloses a drying machine steam supply device and process based on drying tail gas waste heat, and belongs to the technical field of drying machine steam supply. The drying machine steam supply device comprises a dust remover connected with a drying machine tail gas discharge pipe, a heat exchange assembly is arranged on one side of the dust remover, and the heat exchange assembly comprises a heat exchanger connected with the dust remover; tail gas treated by the dust remover exchanges heat with water through a gas inlet pipe mounted on the heat exchanger, and a circulating water tank communicated with the heat exchanger is assembled on one side of the dust remover; through the arrangement of the heat exchange assembly, the heat pump and the flow control assembly, the heat of water vapor in the drying tail gas is recycled to heat circulating water, the circulating water is used as a heat source of the heat pump to generate the steam with the temperature of 140 DEG C or above to be used by the drying machine, the operation cost is greatly saved, and the cost is saved by 40% or above compared with the traditional cost; and condensate water of the drying machine is discharged into the hot water tank through a drain pipe and a drain valve and is recycled as a heat source medium of the drying machine.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of steam supply of drying machine, and particularly relates to a steam supply device and process of drying machine based on drying tail gas waste heat. BACKGROUND

[0002] In the sludge drying process, the wet sludge with high water content is heated by a drying machine under the heating of a heat source to heat the water and organic matter in the wet sludge, to generate water vapor containing a small amount of volatile organic matter, which is called drying waste steam or drying tail gas, and is discharged from the waste gas outlet of the drying machine, and the dry sludge is discharged from the sludge outlet to realize the drying of the sludge.

[0003] The conventional sludge drying machine uses purchased steam or natural gas boiler or electric boiler to generate steam, and uses the steam to heat and dry the water in the sludge in the drying machine. The steam source is relatively high in price (for example, the purchased steam is about 250 yuan / ton), and in the conventional technology, the condensate water of the directly condensed drying tail gas is sent to a water treatment system, and the non-condensable gas is sent to a tail gas treatment device. A large amount of latent heat of the water vapor in the drying tail gas is not effectively recovered, resulting in a great waste. SUMMARY

[0004] The present application aims at solving the problem that in the conventional technology, the latent heat of the vaporization of a large amount of water vapor is not effectively recovered after the directly condensed drying tail gas is sent to a water treatment system and a tail gas treatment system, and proposes a steam supply device and process of drying machine based on drying tail gas waste heat.

[0005] In order to achieve the above-mentioned purpose, the present application adopts the following technical scheme: A steam supply device of drying machine based on drying tail gas waste heat, comprising a dust collector connected with a drying machine tail gas discharge pipe, a heat exchange assembly is arranged on one side of the dust collector, the heat exchange assembly comprises a heat exchanger connected with the dust collector, the tail gas treated by the dust collector is subjected to heat exchange with water through a gas inlet pipe installed on the heat exchanger, and a circulating water tank in communication with the heat exchanger is arranged on one side of the dust collector. A heat pump is arranged on one side of the circulating water tank, and the heated water is sent into the heat pump as a heat source through a circulating pump installed on the circulating water tank to generate steam for the drying machine.

[0006] Further description of the above-mentioned technical scheme: The output end of the heat pump is connected with a water vapor compressor, and the output end of the water vapor compressor is connected with the steam inlet end of the drying machine through a flow control assembly.

[0007] Further description of the above-mentioned technical scheme: The flow control assembly comprises a support and a control box assembled on the support, and a motor with an output end connected with a valve seat is installed on the top of the control box.

[0008] As a further description of the above technical solution: The valve seat is provided with an L-shaped channel and a V-shaped channel, and a junction channel is provided at the center of the valve seat and communicates with the L-shaped channel and the V-shaped channel, and the outlet end of the junction channel is connected with a conveying pipe having one end communicating with the air inlet end of the drying machine through a rotary joint.

[0009] As a further description of the above technical solution: Two inlets are provided on the inner wall of the control box and communicate with the L-shaped channel, and the output end of the water vapor compressor is connected with one of the inlets through a first air supply pipe, and a second air supply pipe is installed in the other inlet.

[0010] As a further description of the above technical solution: The outlet end of the condensate water of the drying machine is connected with a hot water tank through a drain pipe, and the hot water tank is connected with the heat pump through a water supply pipe.

[0011] As a further description of the above technical solution: One end of the heat pump is connected with the heat exchanger through a heat source return water pipe, and the output end of the circulating pump is connected with the heat pump through a heat source water supply pipe.

[0012] A drying machine steam supply process based on drying tail gas waste heat, comprising the following steps: S1, the drying machine uses saturated steam as a heat source to indirectly contact with the sludge to achieve the effect of drying the sludge, and in this process, the water in the sludge is evaporated into water vapor to form drying tail gas; S2, the drying tail gas discharged by the drying machine has a temperature of about 100 DEG C, and after dust removal by a dust remover, the tail gas is subjected to heat exchange with water through a heat exchanger; S3, the heated water flows into the circulating water tank and is sent into the heat pump by the circulating pump to produce 140-180 DEG C steam as a heat source for the drying machine, and in this process, the heat pump can directly produce 140-150 DEG C steam, or 100-130 DEG C steam, which is then heated and pressurized to 150-180 DEG C by a water vapor compressor.

[0013] As described above, due to the adoption of the above technical solution, the beneficial effects of the present application are: By setting the heat exchange assembly, the heat pump and the flow control assembly, the heat of the water vapor in the drying tail gas (about 80% of the steam heat entering the drying machine enters the evaporated tail gas, which has great recycling value) is recovered to heat the circulating water, and the circulating water is used as a heat source for the heat pump to generate steam above 140 DEG C for the drying machine, greatly saving the operating cost, which is more than 40% lower than the traditional method; And the condensate water of the drying machine is discharged into the hot water tank through the drain pipe and the drain valve, and is used as the drying medium for circulation, thereby improving the energy utilization efficiency. At the same time, through the adjustment of the L-shaped channel and the V-shaped channel of the valve seat, five matching modes (only outsourcing, only heat pump, mixed matching, etc.) of outsourcing steam and heat pump steam are realized, which adapt to the dynamic demand when the heat pump capacity fluctuates. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 A schematic diagram of a first perspective of an overall state is shown according to an embodiment of the present application; Figure 2 A schematic diagram of a second perspective of an overall state is shown according to an embodiment of the present application; Figure 3 A schematic diagram of the overall structure of a flow control assembly is shown according to an embodiment of the present application; Figure 4 A schematic diagram of the structure inside the valve seat is shown according to an embodiment of the present application; Figure 5 A schematic diagram of the structure of a control box is shown according to an embodiment of the present application; Figure 6 A schematic diagram of a top view of an overall state is shown according to an embodiment of the present application; Figure 7 A first example flow chart is shown according to an embodiment of the present application; Figure 8 A schematic diagram of the L-shaped channel and the full communication of the inlet is shown according to an embodiment of the present application; Figure 9 A schematic diagram of the L-shaped channel and the half communication of the inlet is shown according to an embodiment of the present application; Figure 10 A schematic diagram of the V-shaped channel and full communication with one of the inlets is shown according to an embodiment of the present application; Figure 11 A schematic diagram of the V-shaped channel and communication with two inlets is shown according to an embodiment of the present application; Figure 12 A schematic diagram of the V-shaped channel and full communication with the other inlet is shown according to an embodiment of the present application; Figure 13 A second example flow chart is shown according to an embodiment of the present application.

[0015] LEGEND: 10, dust collector; 20, heat exchange assembly; 21, heat exchanger; 22, circulating water tank; 23, air inlet pipe; 24, circulating pump; 30, heat pump; 31, water vapor compressor; 40, flow control assembly; 41, bracket; 42, control box; 43, valve seat; 44, L-shaped channel; 45, V-shaped channel; 46, intersection channel; 47, delivery pipe; 48, motor; 50, hot water tank; 51, drain pipe. DETAILED DESCRIPTION

[0016] The technical solutions in the embodiments of the present application will be apparently and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0017] As shown in Figure 1 , Figure 13 As shown in The present application provides a drier steam supply device based on dried tail gas waste heat, which comprises a dust collector 10 connected with a drier tail gas discharge pipe. Preferably, the dust collector 10 is a water film dust collector. The drier is a disc drier, a paddle drier or a thin layer drier. In use, the drier indirectly contacts the sludge with saturated steam as a heat source to achieve the effect of drying the sludge. In this process, the water in the sludge is evaporated into water vapor to form dried tail gas. The temperature of the dried tail gas discharged from the drier is about 100°C (most of which is water vapor, and a small amount is air and odor gas volatilized from the sludge). The dried tail gas needs to be first dedusted by the dust collector 10. At the same time, the dust collector 10 can also maintain the temperature of the tail gas and prevent condensation. In order to use the treated tail gas for heat exchange, a heat exchange assembly 20 is arranged on one side of the dust collector 10. The heat exchange assembly 20 comprises a heat exchanger 21 connected with the dust collector 10. The treated tail gas of the dust collector 10 is heat exchanged with water through an air inlet pipe 23 installed on the heat exchanger 21. A circulating water tank 22 is arranged on one side of the dust collector 10 and is in communication with the heat exchanger 21.

[0018] As shown in Figure 1 , Figure 2 , Figure 6 and Figure 7 In order to use the heat-exchanged hot water as a heat source to produce steam, a heat pump 30 is arranged on one side of the circulating water tank 22. The heat-exchanged hot water is sent into the heat pump 30 through a circulating pump 24 arranged on the circulating water tank 22 as a heat source to produce steam for the drier. In particular, the condensate outlet end of the drier is connected with a hot water tank 50 through a drain pipe 51. Preferably, a drain valve is arranged on the drain pipe 51. The drain valve automatically discharges the steam condensate and non-condensable gases such as air in the drain pipe 51 without leaking steam. The hot water tank 50 is connected to the heat pump 30 through a water supply pipe. Meanwhile, one end of the heat pump 30 is connected to the heat exchanger 21 through a heat source return water pipe, and the output end of the circulating pump 24 is connected to the heat pump 30 through a heat source supply water pipe. The output of heat pump 30 is connected to steam compressor 31. Specifically, the exhaust gas, after dust removal (dust content less than...), The water undergoes heat exchange with heat exchanger 21, and the hot water flows into circulating water tank 22 and is then sent by circulating pump 24 to heat pump 30 as a heat source to produce steam at 140-180℃ as a heat source for the dryer (at this time, the COP of heat pump 30 can reach 2.13 or above). It is worth noting that in this process, heat pump 30 can directly produce steam at 140-150℃ or steam at 100-130℃, which is then heated and pressurized to 150-180℃ by steam compressor 31. It should be noted that the dotted line in the flowchart represents the circulation of low-temperature hot water entering heat exchanger 21, heating up, and then entering heat pump 30. After releasing heat and cooling down at the cold end, it re-enters heat exchanger 21, forming a cycle. The dashed line represents the circulation of steam generated by heat pump 30, which releases heat and condenses into water in the dryer before being sent back to heat pump 30 to generate steam. Heat pump 30 transfers the heat absorbed at the cold end from heat exchanger 21 to the hot end to generate steam, which is then provided as a heat source to the dryer. like Figure 1 , Figure 3 , Figure 4 and Figure 5 As shown, in order to control the steam flow rate into the dryer, the output end of the steam compressor 31 is connected to the steam inlet end of the dryer by installing a flow control component 40. The flow control assembly 40 includes a bracket 41 and a control box 42 mounted on the bracket 41. In particular, the control box 42 includes a housing with a sealing cover installed on the housing. A valve seat 43 is rotatably connected inside the control box 42. Preferably, the valve seat 43 is composed of an upper seat body and a lower seat body spliced ​​together. A motor 48 with its output end connected to the valve seat 43 is installed on the top of the control box 42. like Figure 8 - Figure 12 As shown, an L-shaped channel 44 and a V-shaped channel 45 are provided inside the valve seat 43. A confluence channel 46 connected to the L-shaped channel 44 and the V-shaped channel 45 is provided at the center of the valve seat 43. The outlet end of the confluence channel 46 is connected to a conveying pipe 47 with one end connected to the air inlet end of the dryer through a rotary joint. The control box 42 has two inlets on its inner wall that are connected to the L-shaped channel 44. The output end of the steam compressor 31 is connected to one of the inlets through the first air supply pipe. The other inlet is equipped with a second air supply pipe. Preferably, both the first and second air supply pipes are equipped with solenoid valves. The valve seat 43 is used to control the amount of external steam and heat pump 30 steam supplied into the confluence channel 46 when the solenoid valve is open. This enables five different scenarios: the amount of external steam supplied is the same as the amount of heat pump 30 steam supplied; the amount of external steam supplied is greater than the amount of heat pump 30 steam supplied; the amount of external steam supplied is less than the amount of heat pump 30 steam supplied; only external steam is supplied; or only heat pump 30 steam is supplied. Specifically, the second steam supply pipe is used to transport external steam (specifically, purchased steam, steam generated by an electric boiler, or steam generated by a gas boiler). In particular, the two inlets are also arranged in an L-shape and can be connected to the L-shaped channel 44. At the same time, when the L-shaped channel 44 is fully connected to the two inlets, when the valve seat 43 is driven by the motor 48 to rotate counterclockwise or clockwise, the connection state between the two ports of the L-shaped channel 44 and the two inlets remains the same. It is worth noting that the rotation angle must be less than 30°. When the counterclockwise rotation exceeds 30°, one end of the V-shaped channel 45 will gradually rotate to connect with the second air supply pipe. When the V-shaped channel 45 is fully connected with the second air supply pipe, the first air supply pipe is not connected to the port of any channel. In this state, only external steam can enter the valve seat 43. When the valve seat 45 continues to rotate counterclockwise, the other end of the V-shaped channel 45 will begin to connect with the first container pipe, and the degree of connection will gradually increase. During this process, the degree of connection between the V-shaped channel 45 and the second gas supply pipe will gradually decrease. When it is fully connected with the first gas supply pipe, the second gas supply pipe will not connect with any port of the channel. This allows for five different scenarios to be achieved by rotating the valve seat 43 to different angles: the external steam supply is the same as the steam supply of the heat pump 30, the external steam supply is greater than the steam supply of the heat pump 30, the external steam supply is less than the steam supply of the heat pump 30, only external steam is supplied, or only the steam supply of the heat pump 30 is supplied. These scenarios are designed to meet different steam supply requirements. It is particularly important to note that when the steam supply of the heat pump 30 cannot meet the supply demand, the ratio of the external steam supply to the steam supply of the heat pump 30 needs to be adjusted. Finally, it should be noted that during use, the condensate from the dried exhaust gas must be treated to meet standards before being discharged (not shown in the figure), while the non-condensable gas must be treated to meet standards before being discharged.

[0019] Specifically, the steam supply device for this dryer, based on the waste heat from the drying exhaust gas, operates as follows: 1. Exhaust Gas Treatment Stage: The 100℃ exhaust gas (containing 95% water vapor + 5% air / odor gas) discharged from the dryer enters the dust collector for 10 minutes for dust removal, maintaining the temperature to prevent condensation, and reducing the dust content to < ; 2. Heat exchange and recovery stage: The exhaust gas after dust removal enters the heat exchanger 21 through the air inlet pipe 23 and exchanges heat with the circulating water. The hot water flows into the circulating water tank 22 and is transported to the heat pump 30 by the circulating pump 24 as a heat source. 3. Steam generation stage: Heat pump 30 uses the heat of circulating water to generate steam at 100-150℃. If higher parameters are required, the steam is pressurized to above 150℃ by steam compressor 31 and delivered to flow control component 40. 4. Flow regulation stage: The valve seat 43 is rotated by the motor 48 to adjust the connection between the L-shaped channel 44 and the V-shaped channel 45. Rotate counterclockwise <30°: L-shaped channel 44 connects the first gas supply pipe (heat pump steam) and the second gas supply pipe (purchased steam) to achieve mixing ratio; Rotate counterclockwise >30°: The V-shaped channel 45 is gradually connected to the second gas supply pipe, enabling the supply of only externally purchased steam; Continue rotating until the V-shaped channel 45 is fully connected to the first gas supply pipe: achieving heat pump steam supply only; 5. Steam supply stage: The regulated steam is sent to the dryer through the conveying pipe 47, and serves as a heat source to indirectly contact the sludge to achieve drying. 6. Condensate circulation stage: The condensate from the dryer is discharged into the hot water tank 50 through the drain pipe 51 and the steam trap, and is used as a heat source medium for the dryer in a circulating manner, which reduces the consumption of softened water and improves energy utilization efficiency. 7. Emission treatment stage: The exhaust gas condensate is treated by the water treatment system to meet the standards before being discharged, and the non-condensable gas is purified by the exhaust gas treatment device before being discharged to ensure environmental compliance.

[0020] A steam supply process for a dryer based on waste heat from the drying exhaust gas includes the following steps: S1. The dryer uses saturated steam as a heat source to indirectly contact the sludge to achieve the effect of drying the sludge. During this process, the water in the sludge is evaporated into water vapor to form drying exhaust gas. S2. The temperature of the drying exhaust gas discharged from the dryer is about 100℃. After the exhaust gas is removed by the dust collector 10, it exchanges heat with water through the heat exchanger 21. S3. After heat exchange, the hot water flows into the circulating water tank 22 and is then sent by the circulating pump 24 to the heat pump 30 as a heat source to produce steam at 140-180℃ as a heat source for the dryer. In this process, the heat pump 30 can directly produce steam at 140-150℃ or steam at 100-130℃, which is then heated and pressurized to 150-180℃ by the steam compressor 31.

[0021] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A steam supply device for a dryer based on waste heat from the dryer exhaust gas, comprising a dust collector (10) connected to the exhaust gas discharge pipe of the dryer, characterized in that, A heat exchange assembly (20) is provided on one side of the dust collector (10). The heat exchange assembly (20) includes a heat exchanger (21) connected to the dust collector (10). The exhaust gas treated by the dust collector (10) exchanges heat with water through an air inlet pipe (23) installed on the heat exchanger (21). A circulating water tank (22) connected to the heat exchanger (21) is installed on one side of the dust collector (10). A heat pump (30) is provided on one side of the circulating water tank (22). The hot water after heat exchange is sent into the heat pump (30) by the circulating pump (24) installed on the circulating water tank (22) as a heat source to generate steam for supplying the dryer.

2. The steam supply device for a dryer based on waste heat from drying exhaust gas according to claim 1, characterized in that, The output end of the heat pump (30) is connected to a steam compressor (31), and the output end of the steam compressor (31) is connected to the steam inlet of the dryer through a flow control assembly (40).

3. A steam supply device for a dryer based on waste heat from drying exhaust gas according to claim 2, characterized in that, The flow control assembly (40) includes a bracket (41) and a control box (42) mounted on the bracket (41). A motor (48) with its output end connected to the valve seat (43) is mounted on the top of the control box (42).

4. A steam supply device for a dryer based on waste heat from drying exhaust gas according to claim 3, characterized in that, The valve seat (43) is provided with an L-shaped channel (44) and a V-shaped channel (45). A confluence channel (46) connected to the L-shaped channel (44) and the V-shaped channel (45) is provided at the center of the valve seat (43). The outlet end of the confluence channel (46) is connected to a conveying pipe (47) with one end connected to the air inlet end of the dryer through a rotary joint.

5. A steam supply device for a dryer based on waste heat from drying exhaust gas according to claim 4, characterized in that, The control box (42) has two inlets connected to the L-shaped channel (44) on its inner wall, and the output end of the steam compressor (31) is connected to one of the inlets through the first air supply pipe, and the other inlet is equipped with a second air supply pipe.

6. A steam supply device for a dryer based on waste heat from drying exhaust gas according to claim 1, characterized in that, The condensate outlet of the dryer is connected to a hot water tank (50) via a drain pipe (51), and the hot water tank (50) is connected to a heat pump (30) via a water supply pipe.

7. A steam supply device for a dryer based on waste heat from drying exhaust gas according to claim 6, characterized in that, One end of the heat pump (30) is connected to the heat exchanger (21) through a heat source return water pipe, and the output end of the circulating pump (24) is connected to the heat pump (30) through a heat source supply water pipe.

8. The steam supply process of a steam supply device for a dryer based on waste heat from drying exhaust gas according to any one of claims 1-7, characterized in that, Includes the following steps: S1. The dryer uses saturated steam as a heat source to indirectly contact the sludge to achieve the effect of drying the sludge. During this process, the water in the sludge is evaporated into water vapor to form drying exhaust gas. S2. The temperature of the drying exhaust gas discharged from the dryer is about 100℃. After the exhaust gas is removed by the dust collector (10), it exchanges heat with water through the heat exchanger (21). S3. After heat exchange, the hot water flows into the circulating water tank (22) and is then sent by the circulating pump (24) to the heat pump (30) as a heat source to produce 140-180℃ steam as a heat source for the dryer. In this process, the heat pump (30) can directly produce 140-150℃ steam or 100-130℃ steam, which is then heated and pressurized to 150-180℃ by the steam compressor (31).

Images