Combined heat and power generation system of organic heat carrier furnace

Abstract

According to the combined heat and power generation system of the organic heat carrier furnace, a micro heat conduction oil furnace system is adopted for recovering flue gas waste heat, an organic Rankine cycle unit is adopted for achieving thermal power generation of the flue gas waste heat, flue gas low-temperature corrosion is effectively avoided, meanwhile, efficient recycling and combined heat and power generation of the flue gas waste heat are achieved, operation and adjustment are flexible and convenient, and the combined heat and power generation efficiency is improved. The problems that waste heat of the organic heat carrier furnace is difficult to recycle, and energy-quality matching and utilization are difficult are solved, and implementation and popularization of the organic heat carrier furnace have good economic and social significance.

Description

Technical Field

[0001] The invention belongs to the technical field of boilers, and in particular relates to an organic heat carrier furnace cogeneration system adopting a micro thermal oil furnace and an organic Rankine cycle power generation technology. Background Art

[0002] An organic heat carrier boiler is a special boiler that uses an organic heat carrier as the working medium. The high-temperature flue gas generated by fuel combustion heats the organic heat carrier, i.e., the heat transfer oil. After the temperature of the heat transfer oil is increased, it provides the required heat for the heat-using equipment. When the flue gas generated by fuel combustion is discharged through the chimney, the exhaust gas temperature is related to the temperature of the heat transfer oil entering the furnace. The exhaust gas temperature is generally higher than 230°C, and some are even as high as 350°C, which not only wastes heat but also causes thermal pollution to the environment.

[0003] Most thermal oil boilers do not recover waste heat or only add air preheaters to recover part of the flue gas waste heat. Some processes are equipped with waste heat recovery devices with steam generators such as heat pipe boilers. For example, ZL200420027889.4 provides a thermal oil boiler tail gas waste heat recovery device with a steam generator to recover a certain amount of steam. However, the amount of steam generated by the steam generator is difficult to match the steam load of the steam-using equipment, and the common phenomenon of excess steam venting of the evaporator generator will occur.

[0004] At present, the patented technologies for heat and power cogeneration of thermal oil furnace or organic heat carrier furnace in China are CN201110088264.3-System and method for realizing heat and power cogeneration using thermal oil furnace and semiconductor power generation device, and CN201110088266.2-System and method for realizing heat and power cogeneration of thermal oil furnace using semiconductor power generation device. It is theoretically feasible to realize heat and power cogeneration by combining semiconductor power generation device with thermal oil furnace, but it is difficult to implement. However, organic Rankine cycle power generation technology has matured in waste heat recovery in the medium and low temperature range, and the unit has been miniaturized and can be installed and applied quickly.

[0005] Therefore, how to use organic Rankine cycle power generation technology to reasonably recover the flue gas waste heat of the organic heat carrier furnace, effectively avoid low-temperature corrosion, realize cogeneration of the organic heat carrier furnace, and thus improve the overall thermal efficiency of the organic heat carrier furnace has become a difficult point in research in this field. Summary of the invention

[0006] The purpose of the present invention is to solve the shortcomings of the above-mentioned prior art, adopt organic Rankine cycle power generation technology to achieve efficient recovery of waste heat from flue gas in organic heat carrier furnace, and effectively avoid low-temperature corrosion of flue gas on oil-gas heat exchanger, so as to achieve cogeneration of heat and power in organic heat carrier furnace and achieve the purpose of energy saving and consumption reduction.

[0007] The purpose of the present invention is achieved by the following measures:

[0008] An organic heat carrier furnace cogeneration system, characterized in that the organic heat carrier furnace cogeneration system comprises a high-temperature side heat transfer oil furnace, a low-temperature side micro heat transfer oil furnace and an organic Rankine cycle device,

[0009] The high-temperature side thermal oil furnace comprises a thermal oil furnace body 1, a burner 2, a hot oil pump 7, a heat-using device 3, an oil-gas separator 5, a filter 6 and a connecting pipeline. The thermal oil is sequentially passed through the hot oil pump 7, the thermal oil furnace body 1, the heat-using device 3, the oil-gas separator 5, the filter 6 connected by the pipeline, and then returns to the hot oil pump 7. The high-temperature side thermal oil furnace is provided with a high-level expansion tank 4 and a low-level oil storage tank 8. The separated gas in the oil-gas separator 5 enters the high-level expansion tank 4. The high-level expansion tank 4 is connected to the low-level oil storage tank 8 through an overflow pipe.

[0010] The low-temperature side micro thermal oil furnace comprises a heat storage oil tank 11, a micro thermal oil pump 12, an oil and gas heater 13, an evaporator 15 and connecting pipes thereof.

[0011] The organic Rankine cycle device includes an evaporator 15, an organic working medium gas turbine 17, an organic working medium generator 18, a condenser 20, an organic working medium circulation pump 24 and connecting pipes thereof.

[0012] The oil-gas heater 13 is arranged on the flue 9 of the high-temperature side thermal oil furnace. The flue gas with higher temperature in the flue 9 is discharged after the temperature is reduced by the oil-gas heater 13. The heat-conducting oil drawn from the thermal storage oil tank 11 absorbs the heat of the flue gas in the flue 9 through the micro thermal oil pump 12 and the oil-gas heater 13, and is sent to the evaporator 15 to heat the liquid organic working medium 23 sent by the organic working medium circulation pump 24, and then returns to the thermal storage oil tank 11. The liquid organic working medium 23 sent by the organic working medium circulation pump 24 is heated by the evaporator 15 to generate high-pressure gaseous organic working medium 16, which enters the organic working medium gas turbine 17 to drive the organic working medium generator 18 to generate electricity. The low-pressure and low-temperature gaseous organic working medium 19 coming out of the organic working medium gas turbine 17 enters the condenser 20 and is cooled by the refrigerant 21 to form a liquid organic working medium 23, which enters the organic working medium circulation pump 24, thereby forming an organic heat carrier furnace cogeneration system. The refrigerant 21 with increased temperature forms a heat medium 22 and is discharged.

[0013] The refrigerant of the condenser 20 in the organic Rankine cycle device is air or water.

[0014] The low-level oil storage tank 8 and the heat storage oil tank 11 can be integrated into one.

[0015] When the low-level oil storage tank 8 and the heat storage oil tank 11 are combined into one, nitrogen sealing and heat preservation measures are adopted.

[0016] An external air preheater 14 is provided: the heat transfer oil drawn from the heat storage oil tank 11 passes through a micro heat transfer oil pump 12 and an oil-gas heater 13, absorbs the heat of the flue gas in the flue 9, and is sent to the external air preheater 14 to heat the air sent by the blower 10, and then returns to the heat storage oil tank 11. The air sent by the blower 10 is heated by the external air preheater 14 and then sent to the burner 2 of the high-temperature side heat transfer oil furnace as combustion-supporting air, thereby forming a new type of organic heat carrier furnace in which the high-temperature side heat transfer oil furnace and the low-temperature side micro heat transfer oil furnace are operated in a combined cycle.

[0017] A superheater 25 is provided:

[0018] The heat transfer oil of the high temperature side heat transfer oil furnace is sequentially passed through the hot oil pump 7, the heat transfer oil furnace body 1, the superheater 25, the heat using equipment 3, the oil-gas separator 5, the filter 6 connected by pipelines, and then returned to the hot oil pump 7.

[0019] Or the heat transfer oil of one path of the heat transfer oil furnace at the high temperature side is returned to the heat transfer oil pump 7 through the hot oil pump 7, the heat transfer oil furnace body 1, the heat-using equipment 3, the oil-gas separator 5, and the filter 6 connected by pipelines, and the heat transfer oil of another path of the heat transfer oil furnace at the high temperature side is returned to the hot oil pump 7 through the hot oil pump 7, the heat transfer oil furnace body 1, the superheater 25, the oil-gas separator 5, and the filter 6 connected by pipelines,

[0020] The flue gas with higher temperature in the flue 9 of the high-temperature side thermal oil furnace is discharged after the temperature is reduced by the oil-gas heater 13. The heat-conducting oil drawn from the thermal storage oil tank 11 absorbs the heat of the flue gas in the flue 9 through the micro thermal oil pump 12 and the oil-gas heater 13, and is sent to the evaporator 15 to heat the liquid organic working medium 23 sent by the organic working medium circulation pump 24, and then returns to the thermal storage oil tank 11. The liquid organic working medium 23 sent by the organic working medium circulation pump 24 is heated by the evaporator 15 and the superheater 25 to generate high-pressure gaseous organic working medium 16, which enters the organic working medium gas turbine 17 to drive the organic working medium generator 18 to generate electricity. The low-pressure and low-temperature gaseous organic working medium 19 coming out of the organic working medium gas turbine 17 enters the condenser 20 and is cooled by the refrigerant 21 to form the liquid organic working medium 23. The refrigerant 21 with increased temperature forms the heat medium 22 and is discharged, thereby forming an organic heat carrier furnace cogeneration system.

[0021] The burner 2 of the high temperature side thermal oil furnace uses coal, oil or gas as fuel.

[0022] The oil-gas heater 13 and the flue gas adopt an indirect heat exchange method, and the hot air heated by the oil-gas heater 13 is sent to the thermal oil furnace 1 for use as combustion-supporting air.

[0023] The heat exchange tubes of the oil-gas heater 13 may be plain tubes, finned tubes, serpentine tubes or spiral grooved tubes.

[0024] The oil-gas heater 13 may be a shell and tube heat exchanger, a plate heat exchanger or other types of heat exchangers.

[0025] By controlling the oil inlet temperature of the oil-gas heater 13 (for example, above 90°C), low-temperature corrosion of the oil-gas heater 13 can be effectively avoided. Under the premise of avoiding condensation, the purpose of maximizing the use of flue gas waste heat can be achieved, so that the thermal oil furnace can operate economically and with high thermal efficiency, achieving the purpose of energy saving and consumption reduction.

[0026] The unspecified facilities in the organic heat carrier furnace cogeneration system are matched with reference to or according to the reliable and mature technologies in the known organic heat carrier furnaces.

[0027] Compared with the prior art, the present invention has the following advantages:

[0028] 1. Compared with the prior art, the present invention proposes an organic heat transfer medium furnace cogeneration system, which adds a micro heat transfer medium furnace system and an organic Rankine cycle power generation device to the traditional heat transfer medium furnace system to form a composite organic heat transfer medium furnace combined cycle operation mode cogeneration system, and uses the micro heat transfer medium furnace system to realize organic Rankine cycle power generation of flue gas waste heat, while effectively avoiding low-temperature corrosion of the oil and gas heater, and the flue gas emission temperature can reach about 130°C, which meets the requirements of energy saving and environmental protection;

[0029] 2. Compared with the prior art, the organic heat carrier furnace cogeneration system of the present invention is flexible and convenient in operation and regulation, and utilizes an organic Rankine cycle generator set to facilitate variable load operation condition regulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a structural schematic diagram of a heat and power cogeneration system of an organic heat carrier furnace of the present invention.

[0031] Figure 1 Among them, 1-thermal oil furnace body, 2-burner, 3-heat-using equipment, 4-high-level expansion tank, 5-oil-gas separator, 6-filter, 7-hot oil pump, 8-low-level oil storage tank, 9-flue, 10-blower, 11-thermal storage oil tank, 12-micro thermal oil pump, 13-oil-gas heater, 14-outside air preheater, 15-evaporator, 16-high-pressure gaseous organic working fluid, 17-organic working fluid gas turbine, 18-organic working fluid generator, 19-low-pressure and low-temperature gaseous organic working fluid, 20-condenser, 21-refrigerant, 22-heat medium, 23-liquid organic working fluid, 24-organic working fluid circulation pump, 25-superheater. DETAILED DESCRIPTION

[0032] The following is combined with Figure 1 The present invention is further described in detail with reference to the accompanying drawings and specific examples.

[0033] Embodiment 1:

[0034] An organic heat carrier furnace cogeneration system includes a high-temperature side thermal oil furnace, a low-temperature side micro thermal oil furnace and an organic Rankine cycle device.

[0035] The high-temperature side thermal oil furnace comprises a thermal oil furnace body 1, a burner 2, a hot oil pump 7, a heat-using device 3, an oil-gas separator 5, a filter 6 and a connecting pipeline. The thermal oil is sequentially passed through the hot oil pump 7, the thermal oil furnace body 1, the heat-using device 3, the oil-gas separator 5, the filter 6 connected by the pipeline, and then returns to the hot oil pump 7. The high-temperature side thermal oil furnace is provided with a high-level expansion tank 4 and a low-level oil storage tank 8. The separated gas in the oil-gas separator 5 enters the high-level expansion tank 4. The high-level expansion tank 4 is connected to the low-level oil storage tank 8 through an overflow pipe.

[0036] The low-temperature side micro thermal oil furnace comprises a heat storage oil tank 11, a micro thermal oil pump 12, an oil and gas heater 13, an evaporator 15 and connecting pipes thereof.

[0037] The organic Rankine cycle device includes an evaporator 15, an organic working medium gas turbine 17, an organic working medium generator 18, a condenser 20, an organic working medium circulation pump 24 and connecting pipes thereof.

[0038] The oil-gas heater 13 is arranged on the flue 9 of the high-temperature side thermal oil furnace. The flue gas with higher temperature in the flue 9 is discharged after the temperature is reduced by the oil-gas heater 13. The heat-conducting oil drawn from the thermal storage oil tank 11 absorbs the heat of the flue gas in the flue 9 through the micro thermal oil pump 12 and the oil-gas heater 13, and is sent to the evaporator 15 to heat the liquid organic working medium 23 sent by the organic working medium circulation pump 24, and then returns to the thermal storage oil tank 11. The liquid organic working medium 23 sent by the organic working medium circulation pump 24 is heated by the evaporator 15 to generate high-pressure gaseous organic working medium 16, which enters the organic working medium gas turbine 17 to drive the organic working medium generator 18 to generate electricity. The low-pressure and low-temperature gaseous organic working medium 19 coming out of the organic working medium gas turbine 17 enters the condenser 20 and is cooled by the refrigerant 21 to form a liquid organic working medium 23, which enters the organic working medium circulation pump 24, thereby forming an organic heat carrier furnace cogeneration system. The refrigerant 21 with increased temperature forms a heat medium 22 and is discharged.

[0039] The refrigerant of the condenser 20 in the organic Rankine cycle device is air or water.

[0040] The low-level oil storage tank 8 and the heat storage oil tank 11 can be integrated into one.

[0041] When the low-level oil storage tank 8 and the heat storage oil tank 11 are combined into one, nitrogen sealing and heat preservation measures are adopted.

[0042] An external air preheater 14 is provided: the heat transfer oil drawn from the heat storage oil tank 11 passes through a micro heat transfer oil pump 12 and an oil-gas heater 13, absorbs the heat of the flue gas in the flue 9, and is sent to the external air preheater 14 to heat the air sent by the blower 10, and then returns to the heat storage oil tank 11. The air sent by the blower 10 is heated by the external air preheater 14 and then sent to the burner 2 of the high-temperature side heat transfer oil furnace as combustion-supporting air, thereby forming a new type of organic heat carrier furnace in which the high-temperature side heat transfer oil furnace and the low-temperature side micro heat transfer oil furnace are operated in a combined cycle.

[0043] A superheater 25 is provided:

[0044] The heat transfer oil of the high temperature side heat transfer oil furnace is sequentially passed through the hot oil pump 7, the heat transfer oil furnace body 1, the superheater 25, the heat using equipment 3, the oil-gas separator 5, the filter 6 connected by pipelines, and then returned to the hot oil pump 7.

[0045] The flue gas with higher temperature in the flue 9 of the high-temperature side thermal oil furnace is discharged after the temperature is reduced by the oil-gas heater 13. The heat-conducting oil drawn from the thermal storage oil tank 11 absorbs the heat of the flue gas in the flue 9 through the micro thermal oil pump 12 and the oil-gas heater 13, and is sent to the evaporator 15 to heat the liquid organic working medium 23 sent by the organic working medium circulation pump 24, and then returns to the thermal storage oil tank 11. The liquid organic working medium 23 sent by the organic working medium circulation pump 24 is heated by the evaporator 15 and the superheater 25 to generate high-pressure gaseous organic working medium 16, which enters the organic working medium gas turbine 17 to drive the organic working medium generator 18 to generate electricity. The low-pressure and low-temperature gaseous organic working medium 19 coming out of the organic working medium gas turbine 17 enters the condenser 20 and is cooled by the refrigerant 21 to form the liquid organic working medium 23. The refrigerant 21 with increased temperature forms the heat medium 22 and is discharged, thereby forming an organic heat carrier furnace cogeneration system.

[0046] The burner 2 of the high-temperature side thermal oil furnace uses coal as fuel.

[0047] The oil-gas heater 13 and the flue gas adopt an indirect heat exchange method, and the hot air heated by the oil-gas heater 13 is sent to the thermal oil furnace 1 for use as combustion-supporting air.

[0048] The heat exchange tubes of the oil-gas heater 13 may be plain tubes, finned tubes, serpentine tubes or spiral grooved tubes.

[0049] The oil-gas heater 13 may be a shell and tube heat exchanger, a plate heat exchanger or other types of heat exchangers.

[0050] By controlling the oil inlet temperature of the oil-gas heater 13 (for example, above 90°C), low-temperature corrosion of the oil-gas heater 13 can be effectively avoided. Under the premise of avoiding condensation, the purpose of maximizing the use of flue gas waste heat can be achieved, so that the thermal oil furnace can operate economically and with high thermal efficiency, achieving the purpose of energy saving and consumption reduction.

[0051] The unspecified facilities in the organic heat carrier furnace cogeneration system are matched with reference to or according to the reliable and mature technologies in the known organic heat carrier furnaces.

[0052] Although the present invention has been disclosed as above with preferred embodiments, they are not intended to limit the present invention. Anyone familiar with the art can make various changes or modifications without departing from the spirit and scope of the present invention, which also belong to the protection scope of the present invention. For example, the present invention can use heat transfer oil to recover waste heat, preheat air, and form a closed-loop circulation of heat transfer oil, which can also achieve efficient recovery of flue gas waste heat. Therefore, the protection scope of the present invention shall be based on the definition of the claims of this application.

Claims

1. An organic heat carrier furnace cogeneration system, characterized in that: The organic heat carrier furnace cogeneration system comprises a high-temperature side thermal oil furnace, a low-temperature side micro thermal oil furnace and an organic Rankine cycle device. The high-temperature side thermal oil furnace comprises a thermal oil furnace body (1), a burner (2), a hot oil pump (7), a heat-using device (3), an oil-gas separator (5) and connecting pipelines. The thermal oil passes through the hot oil pump (7), the thermal oil furnace body (1), the heat-using device (3), the oil-gas separator (5) connected by the pipelines in sequence, and then returns to the hot oil pump (7). The high-temperature side thermal oil furnace is provided with a high-position expansion tank (4) and a low-position oil storage tank (8). The gas separated in the oil-gas separator (5) enters the high-position expansion tank (4). The high-position expansion tank (4) is connected to the low-position oil storage tank (8) through an overflow pipe. The low-temperature side micro thermal oil furnace comprises a heat storage oil tank (11), a micro thermal oil pump (12), an oil and gas heater (13), an evaporator (15) and connecting pipes thereof, The organic Rankine cycle device comprises an evaporator (15), an organic working fluid gas turbine (17), an organic working fluid generator (18), a condenser (20), an organic working fluid circulation pump (24) and connecting pipes thereof, The oil-gas heater (13) is arranged on the flue (9) of the high-temperature side thermal oil furnace. The flue gas with a relatively high temperature in the flue (9) is discharged after its temperature is reduced by the oil-gas heater (13). The heat-conducting oil drawn from the thermal oil tank (11) passes through the micro thermal oil pump (12) and the oil-gas heater (13), absorbs the heat of the flue gas in the flue (9), and is then sent to the evaporator (15) to heat the liquid organic working medium (23) sent by the organic working medium circulation pump (24). The heat-conducting oil then returns to the thermal oil tank (11). The liquid organic working medium sent by the organic working medium circulation pump (24) is heated by the evaporator (15). The working fluid (23) is heated by the evaporator (15), and the high-pressure gaseous organic working fluid (16) is generated, which enters the organic working fluid gas turbine (17) to drive the organic working fluid generator (18) to generate electricity. The low-pressure and low-temperature gaseous organic working fluid (19) coming out of the organic working fluid gas turbine (17) enters the condenser (20) and is cooled by the refrigerant (21). The formed liquid organic working fluid (23) enters the organic working fluid circulation pump (24), thereby forming an organic heat carrier furnace cogeneration system. The refrigerant (21) with increased temperature forms a heat medium (22) and is discharged.

2. The organic heat carrier furnace cogeneration system according to claim 1 is characterized in that: The low-level oil storage tank (8) and the heat storage oil tank (11) are integrated into one.

3. The organic heat carrier furnace cogeneration system according to claim 1 is characterized in that: An external air preheater (14) is provided: the heat transfer oil drawn from the heat storage oil tank (11) passes through a micro heat transfer oil pump (12) and an oil-gas heater (13), absorbs the heat of the flue gas in the flue (9), is sent to the external air preheater (14) to heat the air sent by the blower (10), and then returns to the heat storage oil tank (11); the air sent by the blower (10) is heated by the external air preheater (14) and then sent to the burner (2) of the high-temperature side heat transfer oil furnace as combustion-supporting air, thereby forming a combined circulation operation mode of the high-temperature side heat transfer oil furnace and the low-temperature side micro heat transfer oil furnace.

4. The organic heat carrier furnace cogeneration system according to claim 1 is characterized in that: The oil-gas heater (13) is a shell and tube heat exchanger, a plate heat exchanger or other types of heat exchangers.

5. The organic heat carrier furnace cogeneration system according to claim 1 is characterized in that: With superheater (25): The heat transfer oil of the heat transfer oil furnace at the high temperature side is sequentially passed through a hot oil pump (7) connected by pipelines, a heat transfer oil furnace body (1), a superheater (25), a heat-using device (3), an oil-gas separator (5), and a filter (6), and then returns to the hot oil pump (7).

6. The organic heat carrier furnace cogeneration system according to claim 1 is characterized in that: With superheater (25): One path of the heat transfer oil of the high-temperature side heat transfer oil furnace is returned to the heat transfer oil pump (7) via a pipeline-connected heat transfer oil pump (7), a heat transfer oil furnace body (1), a heat-using device (3), an oil-gas separator (5), and a filter (6), and the other path of the heat transfer oil is returned to the heat transfer oil pump (7) via a pipeline-connected heat transfer oil pump (7), a heat transfer oil furnace body (1), a superheater (25), an oil-gas separator (5), and a filter (6).

7. The organic heat carrier furnace cogeneration system according to claim 1 is characterized in that: The burner (2) of the high-temperature side thermal oil furnace uses coal, oil or gas as fuel.

8. The organic heat carrier furnace cogeneration system according to claim 2 is characterized in that: The low-level oil storage tank (8) adopts nitrogen sealing and heat preservation measures.

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