Flue gas heat recycling system and method for heat conduction oil boiler

Abstract

The invention relates to the technical field of boiler flue gas recycling, and discloses a heat conduction oil boiler flue gas heat recycling system and method.The heat conduction oil boiler flue gas heat recycling system comprises a heat conduction oil boiler, a hot water pool and a living water pool, the heat conduction oil boiler is connected with a flue gas pipeline, and a first-stage energy saver and a second-stage energy saver are sequentially arranged on the flue pipeline; the second-stage energy saver is connected with the hot water pool through a water inlet pipeline, the second-stage energy saver is connected with the first-stage energy saver through a first pipeline, and the first-stage energy saver is connected with the hot water pool through a water return pipeline; the hot water tank is connected with the living water tank through a second pipeline, and the living water tank is connected with the reverse osmosis unit; the secondary energy saver is additionally arranged in the flue gas pipeline, and the pipeline structure is transformed, so that the purpose of improving the flue gas heat utilization efficiency is achieved; meanwhile, a heat conduction oil boiler flue gas heat recycling system is combined with the reverse osmosis unit, so that the water inlet temperature of the reverse osmosis unit can be increased, the water yield of reverse osmosis equipment is improved, and the operation conditions of the steam boiler are ensured.

Description

Technical Field

[0001] The invention relates to the technical field of boiler flue gas recycling, and in particular to a system and method for recycling heat of flue gas from a thermal oil boiler. Background Art

[0002] At present, most boilers use post-economizers, in which the waste heat of flue gas is recycled by exchanging heat between high-temperature flue gas and water. The economizer is generally arranged on the flue gas pipe between the boiler and the chimney. The water heated by heat exchange returns to the hot water pool and can be used as water for workshop cleaning. The inventor found that the exhaust temperature of the thermal oil boiler is still high after passing through the first-level economizer, higher than 120°C, and there is a problem of heat waste; in addition, the water source of the current reverse osmosis equipment is the cold water in the domestic water pool. In winter, the reverse osmosis equipment is affected by the water temperature of the domestic water pool. The lowest temperature of the water in the domestic water pool in winter is nearly 2°C, and the filtration of the reverse osmosis unit is reduced by 50%. If the water temperature is too low, it is easy to have a low water production problem, which cannot meet the water needs of the steam boiler. Summary of the invention

[0003] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a system and method for recycling the heat of flue gas from a thermal oil boiler. A secondary economizer is added to the flue gas pipeline and the pipeline structure is modified to achieve the purpose of improving the efficiency of flue gas heat utilization. At the same time, the heat recycling system for the flue gas from the thermal oil boiler is combined with a reverse osmosis unit to increase the water inlet temperature of the reverse osmosis unit and increase the water output of the reverse osmosis equipment, thereby ensuring the operating conditions of the steam boiler.

[0004] In order to achieve the above object, the present invention is implemented through the following technical solutions:

[0005] In a first aspect, a heat recycling system for flue gas from a thermal oil boiler comprises a thermal oil boiler, a hot water tank and a domestic water tank, wherein the thermal oil boiler is connected to a flue gas duct, and a primary economizer and a secondary economizer are sequentially arranged on the flue duct; the secondary economizer is connected to the hot water tank via an inlet pipe, the secondary economizer is connected to the primary economizer via a first pipe, and the primary economizer is connected to the hot water tank via a return pipe; the hot water tank is connected to an outlet pipe of a domestic water tank via a second pipe, and the outlet pipe of the domestic water tank is connected to a reverse osmosis unit.

[0006] As a further implementation method, the end of the flue gas duct extends to the top of the roof to connect to the chimney, and the secondary economizer is arranged between the primary economizer and the chimney, and the secondary economizer is arranged close to the bottom of the chimney.

[0007] As a further implementation method, the water inlet pipe is connected to the secondary energy saver through a water pump in a pump room, and a first valve is provided on the water inlet pipe near the inlet of the secondary energy saver.

[0008] As a further implementation, the water inlet pipe is connected to the primary economizer via a first branch pipe with a second valve.

[0009] As a further implementation, a third valve is provided on the first pipeline near the inlet of the first-stage economizer.

[0010] As a further implementation method, the first pipeline is also connected to the return pipeline through a second branch pipeline with a fourth valve; the switching of the first-stage energy saver and the second-stage energy saver in series and in parallel is achieved through the combined opening and closing of the first valve, the second valve, the third valve and the fourth valve.

[0011] As a further implementation, the water outlet from the second pipeline is used for cleaning the workshop, and the second pipeline is also connected to the water outlet pipeline of the domestic water pool via a third branch pipeline provided with a fifth valve.

[0012] As a further implementation method, the outlet pipe of the domestic water pool is connected to the reverse osmosis unit through a water pump in a pump room. The reverse osmosis unit includes a reverse osmosis device, a reverse osmosis water pool, and a reverse osmosis water tank arranged in sequence. The reverse osmosis water tank is used to supply water to the steam boiler.

[0013] As a further implementation method, a group of flue gas ducts are connected to both sides of the chimney end, and two groups of the thermal oil boiler, the first-level economizer and the second-level economizer are correspondingly arranged.

[0014] In a second aspect, a method for recycling heat from flue gas of a thermal oil boiler adopts any of the above-described systems for recycling heat from flue gas of a thermal oil boiler, comprising the following steps:

[0015] When the economizers are used in series, the second valve and the fourth valve are closed, and the third valve and the first valve are opened. The water in the hot water pool enters the secondary economizer and the primary economizer in turn through the water inlet pipe to heat up with the flue gas discharged by the thermal oil boiler, and then returns to the hot water pool through the return water pipe; the hot water pool provides hot water to the outlet pipe of the domestic water pool through the second pipe, which can increase the inlet water temperature of the reverse osmosis unit;

[0016] When the energy savers are used in parallel, close the third valve, open the first valve, the second valve, and the fourth valve, and the water in the hot water pool enters the first-level energy saver and the second-level energy saver through the water inlet pipe respectively. The water after heat exchange in the second-level energy saver enters the return pipe through the second branch pipe, and then merges with the hot water exchanged by the first-level energy saver discharged into the return pipe and flows back to the hot water pool.

[0017] The beneficial effects of the present invention are as follows:

[0018] 1. The present invention optimizes the project on the basis of the existing technology, by adding a secondary economizer in the flue gas pipeline and modifying the pipeline structure to achieve the purpose of improving the flue gas heat utilization efficiency; at the same time, the thermal oil boiler flue gas heat recycling system is combined with the reverse osmosis unit, and the hot water after heat exchange is mixed with the cold water from the outlet pipe of the domestic water pool. On the basis of improving the utilization rate of the thermal oil boiler flue gas heat, the reverse osmosis unit inlet water temperature can be increased, and the water output of the reverse osmosis equipment can be increased, thereby ensuring the operating conditions of the steam boiler and greatly reducing the operating costs of the enterprise.

[0019] 2. The heat recycling system of the flue gas of the thermal oil boiler of the present invention comprises two groups of thermal oil boilers and two corresponding groups of flue gas pipes, economizers and corresponding valves. The switching of the first-stage economizer and the second-stage economizer in series and in parallel can be realized through the combined opening and closing of the first valve, the second valve, the third valve and the fourth valve; the different heat exchange modes of the flue gas at the end of the two groups of thermal oil boilers can also be realized, and the heat exchange mode is more flexible. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0021] Figure 1 2 is a schematic structural diagram of a heat recycling system for flue gas from a thermal oil boiler according to an embodiment of the present invention;

[0022] Figure 2 It is a structural schematic diagram of an existing thermal oil boiler flue gas heat recycling system;

[0023] Figure 3 Schematic diagram of valve arrangement in an embodiment of the present invention.

[0024] In the figure: the distances or sizes between parts are exaggerated to show the positions of various parts, and the schematic diagram is for reference only.

[0025] Among them: 1. Hot water pool, 2. Thermal oil boiler, 3. Primary energy saver, 4. Flue gas duct, 5. Chimney, 6. Water inlet pipe, 7. Return pipe, 8. Water pump in pump room, 9. Domestic water pool, 10. Reverse osmosis equipment, 11. Reverse osmosis water pool, 12. Reverse osmosis water tank, 13. Steam boiler, 14. Secondary energy saver; 61. First valve, 62. Second valve, 63. Third valve, 64. Fourth valve, 65. Fifth valve. DETAILED DESCRIPTION

[0026] It should be noted that the following detailed description is illustrative and aims to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention pertains.

[0027] As shown in the prior art Figure 2 Two top ends of two heat-conducting oil boilers 2 are respectively connected to a chimney 5 through a flue gas pipeline 4, and the end of the flue gas pipeline 4 extends above the roof to connect to the chimney. A primary economizer 3 is provided at one end of the flue gas pipeline 4 close to the heat-conducting oil boiler 2. A hot water tank 1 is connected to the water inlet end of the primary economizer 3 through a water inlet pipeline 6. The water inlet pipeline 6 also needs to be pressurized by a water pump in a pump house 8 in the pump house. The water inlet pipeline 6 needs to be divided into two paths to enter the primary economizers 3 on the left and right sides respectively. The primary economizer 3 is connected to the hot water tank 1 through a return water pipeline 7. The hot water after heat exchange in the primary economizer 3 returns to the hot water tank 1. The hot water in the hot water tank 1 can be used for workshop cleaning. In addition, the cold water in a domestic water tank 9 comes out from a water outlet pipeline and enters a reverse osmosis unit after being pressurized by a water pump in the pump house. However, the problem with this solution is that the flue gas temperature after the heat-conducting oil boiler passes through the primary economizer is still relatively high, higher than 120 °C, resulting in heat waste; and in winter, the reverse osmosis equipment is affected by the water temperature in the domestic water tank. When the water temperature is too low, the water production volume is likely to be low, which cannot meet the water demand for the steam boiler.

[0028] Embodiment 1

[0029] In a typical implementation manner of the present invention, referring to Figure 1 and Figure 3 As shown, a heat-conducting oil boiler flue gas heat recycling system includes a heat-conducting oil boiler 2, a hot water tank, and a domestic water tank. The heat-conducting oil boiler is connected to a flue gas pipeline. A primary economizer 3 and a secondary economizer 14 are successively provided on the flue gas pipeline; the secondary economizer 14 is connected to the hot water tank 1 through a water inlet pipeline 6. The secondary economizer 14 is connected to the primary economizer 3 through a first pipeline. The primary economizer 3 is connected to the hot water tank 1 through a return water pipeline 7; the hot water tank 1 is connected to the water outlet pipeline of the domestic water tank 9 through a second pipeline, and the water outlet pipeline of the domestic water tank 9 is connected to a reverse osmosis unit.

[0030] This embodiment optimizes the project transformation on the basis of the prior art to achieve the purpose of improving the utilization efficiency of flue gas heat. At the same time, the hot water after heat exchange is mixed with the cold water in the domestic water tank to be used as the water source of the reverse osmosis unit, thereby increasing the water production volume of the reverse osmosis unit.

[0031] As Figure 1As shown, based on two thermal oil boilers 2, two groups of flue gas ducts 4, one group of chimneys 5, and two groups of primary economizers 3, in order to reduce flue gas heat waste, a secondary economizer 14 is arranged at a position near the bottom end of each flue gas duct 4, so that the secondary economizer 14 is arranged between the primary economizer 3 and the chimney 5.

[0032] By disconnecting the original flue gas duct at the roof, cutting off a set length of the flue gas duct 4, and then sealing the inlet and outlet flues of the secondary economizer 14 with the disconnected part of the flue gas duct, it is possible to add a secondary economizer 14 on the original basis, thereby reducing the waste of flue gas heat.

[0033] like Figure 1 As shown, the hot water pool is connected to the secondary energy saver 14 via the water inlet pipe 6, wherein the water inlet pipe 6 at the outlet end of the hot water pool 1 needs to be connected to the water pump in the water pump room 8, and the water pump in the water pump room provides the power required for water circulation.

[0034] like Figure 1 As shown, a first valve 61 is provided on the water inlet pipe 6 near the water inlet of the secondary energy saver 14, and the water inlet pipe is also connected to the water inlet of the primary energy saver through a first branch pipe with a second valve 62. When the first valve 61 and the second valve 62 are both opened, the water in the hot water pool 1 can enter the primary energy saver 3 and the secondary energy saver 14 respectively through the water inlet pipe 6. When only one of the first valve 61 and the second valve 62 is opened, the water in the hot water pool 1 only enters the energy saver with the corresponding valve opened.

[0035] Furthermore, the secondary energy saver 14 is connected to the primary energy saver 3 through a first pipeline, a third valve 63 is provided on the first pipeline near the water inlet of the primary energy saver 3, and the first pipeline is also connected to the return water pipeline 7 through a second branch pipeline with a fourth valve 64, such as Figure 1 The switching of the first-stage economizer and the second-stage economizer in series and in parallel is realized by the combined opening and closing of the first valve, the second valve, the third valve and the fourth valve.

[0036] Specifically, when the second valve 62 and the fourth valve 64 are closed, and the first valve 61 and the third valve are opened, the water in the hot water pool 1 passes through the water inlet pipe 6, first passes through the first valve 61, enters the secondary economizer 14 for heat exchange and temperature rise, and then passes through the first pipe and the third valve 63 to enter the primary economizer 3 for heat exchange, realizing two-stage heat exchange and reducing flue gas heat loss. The hot water after the two-stage heat exchange is discharged from the outlet of the primary economizer 3 and returns to the hot water pool 1 through the return pipe 7, thereby increasing the water temperature in the hot water pool 1. The above process is the case where the two-stage economizers are used in series.

[0037] When two-stage energy savers need to be used in parallel under special conditions, the third valve 63 is closed, and the first valve 61, the second valve 62 and the fourth valve 64 are opened. The water in the hot water pool enters the secondary energy saver 14 through the water inlet pipe under the action of the water pump in the pump room, and enters the primary energy saver 3 through the first branch pipe for heat exchange. The water after heat exchange in the primary energy saver 3 returns to the hot water pool through the return pipe 7. The water after heat exchange in the secondary energy saver 14 enters the return pipe 7 through the first pipe and the second branch pipe with the fourth valve 64, merges with the exchanged water after the primary energy saver, and returns to the hot water pool. The above process is the case of two-stage energy savers being used in parallel.

[0038] When two stages of economizers are connected in parallel, it is also possible that when one of the stages of economizers is damaged, the parallel mode is started, and the inlet valve corresponding to the damaged economizer is closed. The flue gas heat recycling system of the thermal oil boiler of this embodiment includes two groups of thermal oil boilers, and two groups of corresponding economizers and valve structures are also set. The pipeline structure corresponds to the symmetrical distribution of the heat exchange structures at the output ends of the two groups of thermal oil boilers through branches. Therefore, different heat exchange mode switching can be achieved. For example, the first thermal oil boiler adopts a two-stage economizer series working mode, and the second thermal oil boiler 2 adopts a two-stage economizer parallel working mode, and so on. By applying the above-mentioned flue gas heat recycling system to two groups of thermal oil boilers, flexible switching of heat exchange modes can be achieved.

[0039] After heat exchange in the two-stage heat exchanger, the flue gas heat is recovered for the second time, reducing heat waste and increasing the water temperature in the original hot water pool by more than 10°C.

[0040] like Figure 1 and Figure 2 As shown, the hot water pool 1 is connected to the outlet pipe of the living water pool 9 through the second pipe. The water from the second pipe is used for cleaning the workshop. Specifically, the second pipe is pressurized by the water pump in the pump room and the heated hot water is provided to the workshop for cleaning. The second pipe is also connected to the outlet pipe of the living water pool 9 through a third branch pipe with a fifth valve 65. The second pipe near the cleaning station of the workshop is also provided with a corresponding sixth valve. When the sixth valve is closed and the fifth valve 65 is opened, the hot water in the hot water pool can enter the outlet pipe of the living water pool through the third branch pipe and the fifth valve 65, thereby increasing the water temperature supplied from the living water pool to the reverse osmosis unit.

[0041] Since the cold water in the domestic water pool 9 is used as the water source of the reverse osmosis unit, the cold water in the domestic water pool flows out through the outlet pipe and mixes with the hot water in the hot water pool. After the water temperature is increased, the inlet water temperature of the reverse osmosis unit is increased, and the reverse osmosis water production is increased, avoiding the problem of reduced water production due to the influence of the reverse osmosis inlet water temperature, which cannot meet the use of the steam boiler.

[0042] This embodiment combines the heat recycling system of the flue gas of the thermal oil boiler with the reverse osmosis unit. On the basis of improving the utilization rate of the heat of the flue gas of the thermal oil boiler, it can also increase the water inlet temperature of the reverse osmosis unit and increase the water output of the reverse osmosis equipment, thereby ensuring the operating conditions of the steam boiler and greatly reducing the operating costs of the enterprise.

[0043] like Figure 1 As shown, the outlet pipe of the domestic water pool is connected to the reverse osmosis unit through the water pump in the water pump room 8, and the reverse osmosis unit includes a reverse osmosis device 10, a reverse osmosis water pool 11, and a reverse osmosis water tank 12 connected in sequence, and the water outlet of the reverse osmosis water tank 12 is supplied to the steam boiler 13. The reverse osmosis unit is a prior art.

[0044] It can be understood that the water pumps in this embodiment are all arranged in a water pump room, and different pipelines are connected to different water pumps in the water pump room.

[0045] Embodiment 2

[0046] In a typical embodiment of the present invention, reference is made to Figure 1 and Figure 3 As shown, a method for recycling heat of flue gas from a thermal oil boiler adopts the system for recycling heat of flue gas from a thermal oil boiler described in Example 1, comprising the following steps:

[0047] When the primary economizer 3 and the secondary economizer 14 are used in series, the second valve 62 and the fourth valve 64 are closed, and the first valve 61 and the third valve are opened, the water in the hot water pool 1 passes through the water inlet pipe 6 and first passes through the first valve 61 to enter the secondary economizer 14 for heat exchange and temperature rise, and then passes through the first pipe and the third valve 63 to enter the primary economizer 3 for heat exchange, realizing two-stage heat exchange and reducing flue gas heat loss. The hot water after the two-stage heat exchange is discharged from the outlet of the primary economizer 3 and returns to the hot water pool 1 through the return pipe 7, thereby increasing the water temperature in the hot water pool 1.

[0048] When two-stage economizers are used in parallel, the third valve 63 is closed, and the first valve 61, the second valve 62 and the fourth valve 64 are opened. The water in the hot water pool enters the secondary economizer 14 through the water inlet pipe under the action of the water pump in the pump room, and enters the primary economizer 3 through the first branch pipe for heat exchange. The water after heat exchange in the primary economizer 3 returns to the hot water pool through the return pipe 7. The water after heat exchange in the secondary economizer 14 enters the return pipe 7 through the first pipe and the second branch pipe with the fourth valve 64, merges with the hot water after the primary economizer, and returns to the hot water pool.

[0049] When the fifth valve 65 is opened and the sixth valve is closed, the hot water in the hot water pool 1 enters the outlet pipe of the domestic water pool under the action of the water pump in the pump room, thereby increasing the water temperature in the outlet pipe of the domestic water pool, increasing the water inlet temperature of the reverse osmosis unit, and increasing the water production rate of the reverse osmosis unit.

[0050] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A thermal oil boiler flue gas heat recycling system, characterized in that: It includes a thermal oil boiler, a hot water pool and a domestic water pool. The thermal oil boiler is connected to the flue gas duct. The flue duct is provided with a primary energy saver and a secondary energy saver in sequence. The secondary energy saver is connected to the hot water pool through an inlet pipe, the secondary energy saver is connected to the primary energy saver through a first pipe, and the primary energy saver is connected to the hot water pool through a return pipe. The hot water pool is connected to the outlet pipe of the domestic water pool through a second pipe, and the domestic water pool is connected to a reverse osmosis unit through the outlet pipe.

2. A thermal oil boiler flue gas heat recycling system according to claim 1, characterized in that: The end of the flue gas duct extends to the top of the roof and is connected to the chimney. The secondary economizer is arranged between the primary economizer and the chimney, and the secondary economizer is arranged close to the bottom of the chimney.

3. A thermal oil boiler flue gas heat recycling system according to claim 1, characterized in that: The water inlet pipeline is connected to the secondary energy saver through a water pump in a pump room, and a first valve is provided on the water inlet pipeline near the entrance of the secondary energy saver.

4. A thermal oil boiler flue gas heat recycling system according to claim 3, characterized in that: The water inlet pipeline is connected to the primary energy saver through a first branch pipeline with a second valve.

5. A thermal oil boiler flue gas heat recycling system according to claim 4, characterized in that: A third valve is provided on the first pipeline near the inlet of the first-stage economizer.

6. A thermal oil boiler flue gas heat recycling system according to claim 5, characterized in that: The first pipeline is also connected to the return pipeline through a second branch pipeline with a fourth valve; the switching of the first-stage energy saver and the second-stage energy saver in series and in parallel is achieved through the combined opening and closing of the first valve, the second valve, the third valve and the fourth valve.

7. The heat circulation system of flue gas from a thermal oil boiler according to claim 1 is characterized in that: The water outlet of the second pipeline is used for cleaning the workshop, and the second pipeline is also connected to the water outlet pipeline of the living water pool through a third branch pipeline provided with a fifth valve.

8. A thermal oil boiler flue gas heat recycling system according to claim 7, characterized in that: The outlet pipe of the domestic water pool is connected to the reverse osmosis unit through a water pump in a pump room. The reverse osmosis unit includes a reverse osmosis device, a reverse osmosis water pool, and a reverse osmosis water tank which are arranged in sequence. The reverse osmosis water tank is used to supply water to the steam boiler.

9. The heat circulation system of flue gas from a thermal oil boiler according to claim 2, characterized in that: A group of flue gas pipes are connected to both sides of the end of the chimney, and two groups of the thermal oil boiler, the first-level economizer and the second-level economizer are correspondingly arranged.

10. A method for recycling heat from flue gas of a thermal oil boiler, characterized in that: The heat recycling system for flue gas from a thermal oil boiler as claimed in claim 5 comprises the following steps: When the energy savers are used in series, the second valve and the fourth valve are closed, and the third valve and the first valve are opened. The water in the hot water pool enters the secondary energy saver and the primary energy saver in turn through the water inlet pipe to exchange heat with the flue gas discharged by the thermal oil boiler and heat up the temperature, and then returns to the hot water pool through the return water pipe; the hot water pool provides hot water to the outlet pipe of the domestic water pool through the second pipe, which can increase the inlet water temperature of the reverse osmosis unit; when the energy savers are used in parallel, the third valve is closed, and the first valve, the second valve, and the fourth valve are opened. The water in the hot water pool enters the primary energy saver and the secondary energy saver respectively through the water inlet pipe, and the water after heat exchange in the secondary energy saver enters the return water pipe through the second branch pipe, and flows back to the hot water pool after merging with the heat exchange water discharged from the primary energy saver to the return water pipe; after the medium-heated water in the hot water pool enters the domestic water pool through the second pipe, the water temperature in the domestic water pool is increased, the inlet water temperature of the reverse osmosis unit is increased, and the water production rate of the reverse osmosis unit is increased.

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