Novel boiler flue gas waste heat recycling system

Abstract

The utility model relates to a novel boiler flue gas waste heat recycling system, which aims to overcome the defects in the prior art and comprises a flue gas dust remover, a steam generator, a flue gas-water heat exchanger, a water ring vacuum pump and a flue spraying device. Spraying water is stored in the spraying water circulating water tank and is not discharged. And a corrosion-resistant heat exchange coil pipe is arranged in the spraying water circulation water tank to exchange heat for inlet water, so that the waste heat recovery effect is improved. And when the flue gas waste heat recovery heat exchanger needs to descale a heat exchange pipe after being used for a period of time, related pipeline valves are switched, the acid waste water is used for flushing the heat exchange coil pipe of the waste heat recovery heat exchanger, and the acid waste water is used for dissolving scale, so that a very good descaling effect is achieved, and the device is environment-friendly and energy-saving. The novel boiler flue gas waste heat recycling system is simple in structure, convenient to use, energy-saving, environment-friendly and suitable for various industrial boilers and civil boilers.

Description

Technical Field

[0001] The utility model relates to a novel boiler flue gas waste heat recovery and utilization system. Background Art

[0002] In the existing boiler flue gas waste heat recovery and utilization system, if the flue gas coming out of the flue gas dust collector is sprayed and purified, acidic wastewater will be produced. If the acidic wastewater is discharged directly, it will inevitably pollute the environment. In addition, when the existing boiler flue gas waste heat recovery and utilization system is working, the clean water flows through the tube side and the flue gas flows through the shell side. The heat exchange tubes are prone to scaling and clogging. In addition, most of the flue gas-water heat exchangers are located at the top of the boiler, making descaling inconvenient and requiring improvement. Summary of the Invention

[0003] The technical problem to be solved by the utility model is how to overcome the above-mentioned defects of the prior art and provide a new boiler flue gas waste heat recovery and utilization system which is simple in structure, easy to use, energy-saving and environmentally friendly.

[0004] In order to solve the above technical problems, the present invention relates to a new type of boiler flue gas waste heat recovery and utilization system, which includes a flue gas dust collector, a steam generator, a flue gas water heat exchanger and a water ring vacuum pump. The steam generator and the flue gas water heat exchanger both include a shell and a heat exchange tube arranged in the shell. The top of the shell is provided with an inlet pipe and an outlet pipe communicating with the two ends of the heat exchange tube. The heat exchange tube is composed of a plurality of U-shaped tubes. A plurality of baffles are arranged on the U-shaped tubes at intervals. Under the influence of the baffles, a shell side is formed in the internal space of the shell below the substrate. The shell is provided with a The air inlet and air outlet are characterized in that: it also includes a flue spray device, which includes a flue spray chamber, a circulating spray water tank and a spray water pump. The flue spray chamber is provided with an air inlet pipe and an air outlet pipe, and a water distribution plate is provided above the flue spray chamber. The water distribution plate separates a water distribution tank above the flue spray chamber, and the water distribution plate is densely covered with a plurality of spray through holes. The bottom of the flue spray chamber and the circulating spray water tank are both provided with a water outlet pipe. The water outlet pipe of the flue spray chamber is connected to the circulating spray water tank, and the water outlet pipe of the circulating spray water tank is connected to the inlet of the spray water pump. The outlet pipe of the spray water pump is connected with a main road with a spray water valve and a bypass with a descaling liquid inlet valve. The main road with a spray water valve leads to the water distribution tank. The air inlet pipe of the flue spray chamber is connected to the outlet of the flue gas dust collector. The air outlet pipe of the flue spray chamber is connected to the air inlet on the shell of the steam generator. The air outlet on the shell of the steam generator is connected to the air inlet on the shell of the smoke-water heat exchanger. The air outlet on the shell of the smoke-water heat exchanger is connected to the inlet of the water ring vacuum pump through a pipeline. A water inlet valve is provided on the water supply main pipe, and is connected to the bypass with a descaling liquid inlet valve. The bypass is connected to the inlet pipe of the smoke-water heat exchanger. The outlet pipe of the smoke-water heat exchanger is connected to two pipes. One pipe outputs hot water through a pipe with a hot water valve, and the other pipe is connected to the inlet pipe of the steam generator through a pipe with a steam generator inlet valve. The outlet pipe of the steam generator is provided with a steam valve to output steam; the circulating spray water tank is equipped with a water injection pipe with a water injection valve, and the pipe between the hot water valve and the outlet pipe of the steam generator is also provided with a return pipe, which is provided with a descaling return valve, and the lower end of the return pipe leads to the circulating spray water tank.

[0005] This design recycles the acid wastewater generated by the flue gas purification spray, storing it in a spray water circulation tank and preventing its discharge. The spray water circulation tank houses corrosion-resistant heat exchange coils for heat exchange with incoming water, enhancing waste heat recovery. When the heat exchanger tubes of the flue gas waste heat recovery heat exchanger require descaling after a period of use, the relevant pipeline valves are switched to flush the heat exchanger coils with acidic wastewater, dissolving scale with the acidic wastewater for optimal descaling, ensuring environmental protection and energy conservation.

[0006] As an optimization, the smoke-water heat exchanger includes N serially connected shell-and-tube heat exchangers, where N is a positive integer and N≤5. This design has a simple structure and is easy to install and maintain.

[0007] The novel boiler flue gas waste heat recovery and utilization system has a simple structure, is easy to use, energy-saving and environmentally friendly, and is suitable for use in various industrial boilers and civil boilers. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The following is a further description of the new boiler flue gas waste heat recovery and utilization system with reference to the accompanying drawings:

[0009] Figure 1 This is a schematic diagram of the equipment flow of the new boiler flue gas waste heat recovery and utilization system;

[0010] Figure 2 This is a schematic diagram of the process of generating hot water and steam by the new boiler flue gas waste heat recovery and utilization system;

[0011] Figure 3 This is a schematic diagram of the equipment flow of the flue spray device in the new boiler flue gas waste heat recovery and utilization system;

[0012] Figure 4 The present invention is a schematic diagram of a process for descaling heat exchange tubes by using spray water in a new boiler flue gas waste heat recovery and utilization system.

[0013] In the figure: 1 is a steam generator, 2 is a smoke-water heat exchanger, 3 is a water ring vacuum pump, 4 is a heat exchange tube, 5 is a partition, 6 is a base plate, 7 is an inlet pipe, 8 is an outlet pipe, 9 is a baffle, 10 is an air inlet, 11 is an air outlet, 12 is a flue spray chamber, 121 is an air inlet pipe, 122 is an air outlet pipe, 13 is a circulating spray water tank, 131 is a heat exchange coil, 14 is a spray water pump, 15 is a water distribution plate, 16 is a water distribution tank, 17 is a water outlet pipe, 18 is a spray water valve, 19 is a descaling liquid inlet valve, 20 is a water inlet valve, 21 is a sewage valve, 22 is a water injection valve, 23 is a hot water valve, 24 is a steam generator water inlet valve, 25 is a steam valve, and 26 is a descaling liquid return valve. DETAILED DESCRIPTION

[0014] Implementation method 1: Figure 1As shown, the novel boiler flue gas waste heat recovery and utilization system includes a flue gas dust collector (not shown in the figure), a steam generator 1, a flue gas water heat exchanger 2 and a water ring vacuum pump 3. The steam generator 1 and the flue gas water heat exchanger 2 both include a shell and a heat exchange tube 4 arranged in the shell. A partition 5 and a base plate 6 are provided on the top of the shell. The base plate 6 separates the top space of the shell from other internal spaces of the shell. The partition 5 separates the top space of the shell above the base plate 6 into an inlet area and an outlet area. An inlet pipe 7 and an outlet pipe 8 are provided on the top of the shell, which are respectively connected to the inlet area and the outlet area. The heat exchange tube 4 is composed of a plurality of U-shaped tubes. The two ends of each U-shaped tube pass through the base plate from bottom to top and are respectively connected to the inlet area and the outlet area. The U-shaped tube is provided with a plurality of tubes at intervals. A deflection baffle 9 is affected by the deflection baffle 9. A shell side is formed in the internal space of the shell below the substrate 6. The shell is provided with an air inlet 10 and an air outlet 11 which are communicated with the upper and lower ends of the shell side. The feature is that it also includes a flue spray device, which includes a flue spray chamber 12, a circulating spray water tank 13 and a spray water pump 14. The flue spray chamber 12 is provided with an air inlet pipe 121 and an air outlet pipe 122. A water distribution plate 15 is provided above the flue spray chamber 12. The water distribution plate 15 separates a water distribution tank 16 above the flue spray chamber 12, and a plurality of spray through holes are densely distributed on the water distribution plate 15. The bottom of the flue spray chamber 12 and the circulating spray water tank 13 are both provided with a water outlet pipe 17. The water outlet pipe 17 of the flue spray chamber 12 is connected to the circulating spray water tank 13. The water tank 13 and the water outlet pipe 17 of the circulating spray water tank 13 are connected to the inlet of the spray water pump 14. The outlet pipe of the spray water pump 14 is connected to the main road with a spray water valve 18 and a bypass with a descaling liquid inlet valve 19. The main road with the spray water valve 18 leads to the water distribution tank 16. The air inlet pipe of the flue spray chamber 12 is connected to the outlet of the flue gas dust collector. The air outlet pipe 122 of the flue spray chamber 12 is connected to the air inlet 10 on the shell of the steam generator 1. The air outlet 11 on the shell of the steam generator 1 is connected to the air inlet 10 on the shell of the smoke-water heat exchanger 2. The air outlet 11 on the shell of the smoke-water heat exchanger 2 is connected to the inlet of the water ring vacuum pump 3 through a pipeline. A water inlet valve 20 is provided on the water supply main pipe. A heat exchange coil is provided in the circulating spray water tank 13. 131, the water supply main is connected to one end of the heat exchange coil 131, and the other end of the heat exchange coil 131 is connected to the inlet pipe 7 of the smoke-water heat exchanger 2 together with the bypass with the descaling liquid inlet valve 19. The outlet pipe 8 of the smoke-water heat exchanger 2 is connected with two pipes, one of which outputs hot water through a pipe with a hot water valve 23, and the other is connected to the inlet pipe 7 of the steam generator 1 through a pipe with a steam generator water inlet valve 24. The outlet pipe 8 of the steam generator 1 is provided with a steam valve 25 to output steam; the circulating spray water tank 13 is equipped with a water injection pipe with a water injection valve 22, and a return pipe is also provided on the pipe between the hot water valve 23 and the outlet pipe 8 of the steam generator 1. The return pipe is provided with a descaling return valve 26, and the lower end of the return pipe is connected to the circulating spray water tank 13.A drain pipe is provided at the bottom of the steam generator 1 and the smoke-water heat exchanger 2 , the lower end of which leads to the circulating spray water tank 13 , and a drain valve 21 is provided on the drain pipe.

[0015] The smoke-water heat exchanger 2 includes N serially connected shell-and-tube heat exchangers, where N is a positive integer, N≤5, Figure 1 、 2 The flue gas-water heat exchanger 2 in 4 includes two shell-and-tube heat exchangers, the heat exchange tubes 4 and shell sides of the two are connected in series, and the water and flue gas flow in countercurrent to exchange heat.

[0016] The spray water valve 18, descaling liquid inlet valve 19, water inlet valve 20, drain valve 21, water injection valve 22, hot water valve 23, steam generator water inlet valve 24, steam valve 25, and descaling liquid return valve 26 all include manual valves and solenoid valves. The manual valves are usually open, and remote control is achieved by switching the solenoid valves. The relevant manual valves can be closed on site when necessary.

[0017] like Figure 2 As shown, when the novel boiler flue gas waste heat recovery and utilization system is in operation, the water inlet valve 20, the steam generator water inlet valve 24 and the steam valve 25 are opened, and the water from the water supply main first enters the heat exchange coil 131, and then enters the heat exchange tube 4 of the flue gas-water heat exchanger 2, exchanges heat with the flue gas from the steam generator to generate hot water. The hot water enters the heat exchange tube 4 of the steam generator 1 through the steam generator water inlet valve 24, exchanges heat with the flue gas from the flue spray chamber 12 to generate steam, and is output to the outside through the steam valve 25.

[0018] When hot water is needed, the hot water valve 23 can be opened to draw out some of the hot water for industrial or civilian use.

[0019] like Figure 3 As shown, before the flue spray device operates, the water filling valve 22 is opened to inject an appropriate amount of water into the circulating spray water tank 13. The bypass with the descaling inlet valve 19 is then closed, the spray water pump 14 is started, and the main circuit with the spray water valve 18 is opened. The water in the circulating spray water tank 13 flows through the spray water pump 14 and the main circuit with the spray water valve 18, enters the water distribution tank 16, and is sprayed out of the spray holes on the water distribution plate 15. During its fall, it comes into contact with the flue gas from the flue gas dust collector and absorbs gases such as nitrogen oxides in the flue gas. It then falls to the bottom of the flue spray chamber 12 and flows back to the circulating spray water tank 13 through the outlet pipe 17, where it circulates. After a period of circulation, the water in the circulating spray water tank 13 gradually becomes acidic. The water in the circulating spray water tank 13 is not directly discharged.

[0020] like Figure 4As shown, after a period of operation, scale gradually forms on the inner walls of the heat exchange tubes 4 in the steam generator 1 and the smoke-water heat exchanger 2. At this time, the water inlet valve 20, the hot water valve 23, the steam valve 25 and the spray water valve 18 are closed, and the descaling liquid inlet valve 19 and the descaling liquid return valve 26 are opened. The acidic water in the circulated spray water tank 13 enters the smoke-water heat exchanger 2 and the heat exchange tubes 4 of the steam generator 1 through the spray water pump 14, dissolving and flushing the scale on the inner walls of the heat exchange tubes 4. The descaling return valve 26 returns water to the circulating spray water tank 13, thereby reducing wastewater discharge and eliminating scale. After descaling is completed, first close the descaling inlet valve 19, open the water inlet valve 20, and use water from the main water supply to enter the steam generator 1, the heat exchange pipe 4 in the smoke-water heat exchanger 2, and the descaling return valve 26 for flushing. After 3 to 5 minutes, close the descaling return valve 26, open the hot water valve 23 and steam valve 25, and the production of hot water and steam can be resumed. Open the spray water valve 18 to restore the flue spray device.

[0021] When the novel boiler flue gas waste heat recovery system is working, water and smoke will accumulate at the bottom of the steam generator 1 and the smoke-water heat exchanger 2. At this time, the drain valve 21 is opened to introduce the accumulated water and smoke into the circulating spray water tank 13. The circulating spray water tank 13 is cleaned every once in a while.

Claims

1. A novel boiler flue gas waste heat recovery and utilization system comprises a flue gas dust collector, a steam generator, a flue gas water heat exchanger, and a water ring vacuum pump. The steam generator and flue gas water heat exchanger each comprise a housing and heat exchange tubes disposed within the housing. The top of the housing is provided with an inlet pipe and an outlet pipe communicating with each end of the heat exchange tube. The heat exchange tubes are composed of a plurality of U-shaped tubes, each of which is provided with a plurality of baffles at intervals. Under the influence of the baffles, the interior space of the housing below the base plate forms a shell side. The housing is provided with an air inlet and an air outlet communicating with the upper and lower ends of the shell side. The system is characterized by: It also includes a flue spray device, which includes a flue spray chamber, a circulating spray water tank and a spray water pump. The flue spray chamber is provided with an air inlet pipe and an air outlet pipe. A water distribution plate is provided above the flue spray chamber. The water distribution plate separates a water distribution tank above the flue spray chamber, and a plurality of spray through holes are densely distributed on the water distribution plate. Water outlet pipes are provided at the bottom of the flue spray chamber and the circulating spray water tank. The water outlet pipe of the flue spray chamber leads to the circulating spray water tank. The water outlet pipe of the circulating spray water tank is connected to the inlet of the spray water pump. The outlet pipe of the spray water pump is connected to a main line with a spray water valve and a bypass with a descaling liquid inlet valve. The main line with the spray water valve leads to the water distribution tank. The air inlet pipe of the flue spray chamber is connected to the outlet of the flue gas dust collector. The air outlet pipe of the flue spray chamber is connected to the air inlet on the shell of the steam generator. The air outlet on the shell of the steam generator is communicated with the air inlet on the shell of the smoke-water heat exchanger. The air outlet on the shell of the smoke-water heat exchanger is communicated with the inlet of the water ring vacuum pump through a pipe. The water supply main is provided with a water inlet valve, and is communicated with the inlet pipe of the smoke-water heat exchanger together with a bypass with a descaling liquid inlet valve. The outlet pipe of the smoke-water heat exchanger is connected with two pipes, one of which outputs hot water through a pipe with a hot water valve, and the other is communicated with the inlet pipe of the steam generator through a pipe with a steam generator water inlet valve. The outlet pipe of the steam generator is provided with a steam valve to output steam; the circulating spray water tank is provided with a water injection pipe with a water injection valve, and a return liquid pipe is also provided on the pipe between the hot water valve and the outlet pipe of the steam generator. The return liquid pipe is provided with a descaling return liquid valve, and the lower end of the return liquid pipe leads to the circulating spray water tank.

2. The novel boiler flue gas waste heat recovery and utilization system according to claim 1 is characterized in that: The smoke-water heat exchanger includes N serially connected shell-and-tube heat exchangers, where N is a positive integer and N≤5.

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