A calcium carbide waste heat coupled gas boiler power generation system and method

Abstract

The present invention discloses a calcium carbide waste heat coupled gas boiler power generation system and method, wherein the calcium carbide furnace exhaust gas outlet is connected to the calcium carbide tail gas treatment system inlet, the calcium carbide tail gas treatment system outlet is connected to the gas boiler; the calcium carbide furnace outlet is connected to the calcium carbide liquid high temperature heat exchanger inlet, the high temperature inert gas circulation system is connected to the calcium carbide liquid high temperature heat exchanger and the steam reheater, the steam reheater is connected to the steam turbine, the steam turbine is connected to the gas boiler; the calcium carbide liquid high temperature heat exchanger outlet is connected to the calcium carbide crusher molten calcium carbide liquid inlet, the boiler blower outlet is respectively connected to the air preheater and the calcium carbide crusher cooling air inlet, the calcium carbide crusher outlet is connected to the air preheater outlet; the calcium carbide crusher outlet is connected to the calcium carbide slag low temperature heat exchanger calcium carbide slag inlet, and the low temperature inert gas circulation system is connected to the calcium carbide slag low temperature heat exchanger and the air preheater. The present invention can realize the comprehensive utilization of waste heat of the calcium carbide furnace-gas boiler coupled power generation system.

Description

Technical Field

[0001] The present invention belongs to the technical field of boiler energy conservation, and relates to a waste heat utilization system, and in particular to a calcium carbide waste heat coupled gas boiler power generation system and method. Background Art

[0002] With the deepening of energy-saving and environmental protection concepts, the waste heat utilization technology of boiler systems has become increasingly perfect. However, in some joint production processes, there is still a lot of room for optimization in the comprehensive utilization of waste heat in the entire system. In the production process of calcium carbide, the temperature of molten calcium carbide out of the furnace is as high as 2200℃. In the existing production process, the molten calcium carbide is usually naturally cooled to 60℃, which wastes a lot of waste heat in the process.

[0003] Since the main by-product of the calcium carbide production process is calcium carbide tail gas, which contains a large amount of CO and H 2 The combustible components of molten calcium carbide are therefore combined with gas boiler power generation to form a relatively mature cogeneration system. However, this system does not incorporate the waste heat utilization of molten calcium carbide. Summary of the invention

[0004] In order to solve the problems existing in the prior art, the purpose of the present invention is to provide a calcium carbide waste heat coupled gas boiler power generation system and method. The system divides calcium carbide into high-temperature heat source and low-temperature heat source, and utilizes them respectively in a targeted manner to realize the comprehensive utilization of waste heat from the calcium carbide furnace-gas boiler coupled power generation system.

[0005] The technical solution adopted by the present invention is as follows:

[0006] A calcium carbide waste heat coupled gas boiler power generation system, comprising a calcium carbide furnace, a calcium carbide liquid high-temperature heat exchanger, a calcium carbide crusher, a calcium carbide slag low-temperature heat exchanger, a low-temperature inert gas circulation system, an air preheater, a boiler blower, a high-temperature inert gas circulation system, a steam reheater, a calcium carbide tail gas treatment system, a gas boiler and a steam turbine;

[0007] The exhaust gas outlet of the calcium carbide furnace is connected to the inlet of the calcium carbide tail gas treatment system, and the air outlet of the calcium carbide tail gas treatment system is connected to the gas boiler;

[0008] The liquid outlet of the calcium carbide furnace is connected to the inlet of the calcium carbide liquid high-temperature heat exchanger, the high-temperature inert gas circulation system is connected to the calcium carbide liquid high-temperature heat exchanger and the steam reheater, the high-temperature inert gas circulation system can transfer the heat in the calcium carbide liquid high-temperature heat exchanger to the steam reheater, the steam reheater is connected to the steam turbine, and the steam turbine is connected to the gas boiler;

[0009] The liquid outlet of the calcium carbide liquid high-temperature heat exchanger is connected to the molten calcium carbide liquid inlet of the calcium carbide crusher, and the air outlet of the boiler blower is divided into two paths, one of which is connected to the air preheater, and the other is connected to the cooling air inlet of the calcium carbide crusher and cools and solidifies the molten calcium carbide liquid entering the calcium carbide crusher, and the air outlet of the calcium carbide crusher is connected to the air outlet of the air preheater;

[0010] The outlet of the calcium carbide crusher is connected to the calcium carbide slag inlet of the calcium carbide slag low-temperature heat exchanger, and the low-temperature inert gas circulation system is connected to the calcium carbide slag low-temperature heat exchanger and the air preheater. The low-temperature inert gas circulation system is used to exchange heat in the calcium carbide slag low-temperature heat exchanger to the air preheater.

[0011] Preferably, the liquid outlet of the calcium carbide furnace is provided with a calcium carbide pot for containing molten calcium carbide liquid, and the liquid outlet of the calcium carbide pot is connected to the inlet of the calcium carbide liquid high-temperature heat exchanger.

[0012] Preferably, the high-temperature inert gas circulation system is a closed cycle and is equipped with a high-temperature inert gas circulation fan.

[0013] Preferably, the low-temperature inert gas circulation system is a closed cycle and is equipped with a low-temperature inert gas circulation fan.

[0014] Preferably, an air preheater air inlet regulating valve is provided along the connection between the air outlet of the boiler blower and the air preheater.

[0015] Preferably, a cooling air flow regulating valve is provided along the way where the air outlet of the boiler blower is connected to the calcium carbide crusher.

[0016] Preferably, the slag outlet of the carbide slag low-temperature heat exchanger is connected to a carbide slag recovery device.

[0017] Preferably, the cold inlet of the steam reheater is connected to the outlet of the high-pressure cylinder of the steam turbine, and the hot outlet of the steam reheater is connected to the low-pressure cylinder of the steam turbine.

[0018] The present invention also provides a method for generating electricity by coupling calcium carbide waste heat to a gas-fired boiler. The method is performed by using the calcium carbide waste heat coupled to a gas-fired boiler generating electricity system as described above, and includes the following steps:

[0019] The combustible waste gas generated in the calcium carbide furnace is discharged from the top, enters the calcium carbide tail gas treatment system, and then is sent to the gas boiler for combustion;

[0020] The molten calcium carbide liquid in the calcium carbide furnace is discharged into the calcium carbide liquid high-temperature heat exchanger, and the high-temperature inert gas circulation system transfers the heat of the molten calcium carbide liquid in the calcium carbide liquid high-temperature heat exchanger to the steam reheater; the steam reheater heats the steam and sends it to the steam turbine for power generation;

[0021] The molten calcium carbide liquid cooled by heat exchange in the high-temperature heat exchanger of the calcium carbide liquid enters the calcium carbide crusher, and the cooling air sent in by the boiler blower exchanges heat with the molten calcium carbide liquid to cool and solidify the molten calcium carbide liquid. The heated air after heat exchange is combined with the outlet air of the air preheater and sent to the gas boiler for combustion. The calcium carbide crusher crushes the solidified calcium carbide into slag, and the calcium carbide slag processed in the calcium carbide crusher enters the calcium carbide slag low-temperature heat exchanger, and the low-temperature inert gas circulation system exchanges the heat in the low-temperature heat exchanger of the calcium carbide slag to the air preheater.

[0022] Preferably, after the inert gas in the high-temperature inert gas circulation system absorbs heat in the calcium carbide liquid high-temperature heat exchanger, the temperature rises from 600-800°C to 1500-1700°C; after the inert gas in the low-temperature inert gas circulation system absorbs heat in the calcium carbide slag low-temperature heat exchanger, the temperature rises from 50-100°C to 300-400°C.

[0023] Compared with the prior art, the present invention has at least the following beneficial effects:

[0024] This system makes full use of the waste heat of molten calcium carbide. According to the quality of the waste heat, the waste heat of calcium carbide is divided into high-temperature heat source and low-temperature heat source. The high-temperature heat source is the molten calcium carbide liquid in the calcium carbide liquid high-temperature heat exchanger. The heat in the calcium carbide liquid is exchanged through the high-temperature inert gas circulation system and used to heat the steam in the steam reheater, thereby realizing steam reheating in the high-temperature section; the low-temperature heat source is the calcium carbide slag in the calcium carbide slag low-temperature heat exchanger. The heat in the calcium carbide slag is exchanged through the low-temperature inert gas circulation system and used to heat the air in the air preheater, thereby realizing air preheating in the low-temperature section; in the calcium carbide crusher, the cooling air transported by the boiler blower is heated by the molten calcium carbide liquid, and then combined with the hot air at the outlet of the air preheater and sent to the gas boiler to participate in combustion.

[0025] Furthermore, both air and water will react chemically with calcium carbide, reducing its quality and creating safety hazards. Therefore, the present invention designs a closed cycle of inert gas (i.e., the high-temperature inert gas circulation system is a closed cycle, and the low-temperature inert gas circulation system is a closed cycle) as a heat transfer medium to improve the safety of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the calcium carbide waste heat coupled gas boiler power generation system of the present invention.

[0027] Among them, 1 is a calcium carbide furnace, 2 is a calcium carbide pot, 3 is a calcium carbide liquid high-temperature heat exchanger, 4 is a calcium carbide crusher, 5 is a calcium carbide slag low-temperature heat exchanger, 6 is a calcium carbide slag recovery device, 7 is a low-temperature inert gas circulation fan, 8 is a low-temperature inert gas circulation system, 9 is an air preheater, 10 is a boiler blower, 11 is a high-temperature inert gas circulation fan, 12 is a high-temperature inert gas circulation system, 13 is a steam reheater, 14 is a calcium carbide tail gas treatment system, 15 is a gas boiler, 16 is a steam turbine, 16-1 is a steam turbine high-pressure cylinder, 16-2 is a steam turbine low-pressure cylinder, 17 is a cooling air flow regulating valve, and 18 is an air preheater inlet regulating valve. DETAILED DESCRIPTION

[0028] The present invention is further described in detail below with reference to the accompanying drawings.

[0029] Example

[0030] refer to Figure 1The calcium carbide waste heat coupled power generation system of this embodiment includes a calcium carbide furnace 1, a calcium carbide pot 2, a calcium carbide liquid high-temperature heat exchanger 3, a calcium carbide crusher 4, a calcium carbide slag low-temperature heat exchanger 5, a calcium carbide slag recovery device 6, a low-temperature inert gas circulation system 8, an air preheater 9, a high-temperature inert gas circulation system 12, a steam reheater 13, a calcium carbide tail gas treatment system 14, a gas boiler 15, and a steam turbine 16. The exhaust gas outlet of the calcium carbide furnace 1 is connected to the inlet of the calcium carbide tail gas treatment system 14, and the air outlet of the calcium carbide tail gas treatment system 14 is connected to the gas boiler 15; the liquid outlet of the calcium carbide furnace 1 is connected to the inlet of the calcium carbide liquid high-temperature heat exchanger 3, and the high-temperature inert gas circulation system 12 is connected to the calcium carbide liquid high-temperature heat exchanger 3 and the steam reheater 13. The high-temperature inert gas circulation system 12 can transfer the heat in the calcium carbide liquid high-temperature heat exchanger 3 to the steam reheater 13, and the steam reheater 13 is connected to the steam turbine 16, and the steam turbine 16 is connected to the gas boiler 15; the liquid outlet of the calcium carbide liquid high-temperature heat exchanger 3 is connected to the inlet of the calcium carbide crusher 4. The molten calcium carbide liquid inlet is connected, and the air outlet of the boiler blower 10 is divided into two paths, one of which is connected to the air preheater 9, and the other is connected to the cooling air inlet of the calcium carbide crusher 4 and cools and solidifies the molten calcium carbide liquid entering the calcium carbide crusher 4. The air outlet of the calcium carbide crusher 4 is connected to the air outlet of the air preheater 9; the outlet of the calcium carbide crusher 4 is connected to the calcium carbide slag inlet of the calcium carbide slag low-temperature heat exchanger 5, and the low-temperature inert gas circulation system 8 is connected to the calcium carbide slag low-temperature heat exchanger 5 and the air preheater 9. The low-temperature inert gas circulation system 8 is used to heat the heat in the calcium carbide slag low-temperature heat exchanger 5 to the air preheater 9. The high-temperature inert gas circulation system 12 is a closed cycle and is equipped with a high-temperature inert gas circulation fan 11. The low-temperature inert gas circulation system 8 is a closed cycle and is equipped with a low-temperature inert gas circulation fan 7. An air preheater air inlet regulating valve 18 is provided on the way where the air outlet of the boiler blower 10 is connected to the air preheater 9. A cooling air flow regulating valve 17 is provided along the way where the air outlet of the boiler blower 10 is connected to the calcium carbide crusher 4. The slag outlet of the calcium carbide slag low-temperature heat exchanger 5 is connected to the calcium carbide slag recovery device 6. The cold inlet of the steam reheater 13 is connected to the outlet of the steam turbine high-pressure cylinder 16-1, and the hot outlet of the steam reheater 13 is connected to the steam turbine low-pressure cylinder 16-2.

[0031] The molten calcium carbide liquid in the calcium carbide furnace 1 is discharged into the calcium carbide pot 2 below, and is transferred to the calcium carbide liquid high-temperature heat exchanger 3 through the calcium carbide pot 2 to exchange heat with the inert gas in the high-temperature inert gas circulation system 12. After the heat exchange, the calcium carbide liquid enters the calcium carbide crusher 4, where the calcium carbide liquid is cooled and solidified by cooling air and crushed into slag to form calcium carbide slag. The calcium carbide slag enters the calcium carbide slag low-temperature heat exchanger 5 to exchange heat with the inert gas in the low-temperature inert gas circulation system 8, and then enters the calcium carbide slag recovery device 6.

[0032] The byproduct combustible waste gas in the calcium carbide furnace 1 is discharged from the top, enters the calcium carbide tail gas treatment system 14, and is then sent to the gas boiler 15 for combustion to generate steam for power generation.

[0033] The heat source medium of the calcium carbide liquid high-temperature heat exchanger 3 is the molten calcium carbide liquid from the calcium carbide pot 2, and the cold source medium is the inert gas in the high-temperature inert gas circulation system 12.

[0034] The calcium carbide crusher 4 is cooled by a channel of cold air branched off by the boiler blower 10. The calcium carbide liquid that has been cooled from the calcium carbide liquid high-temperature heat exchanger 3 solidifies after cooling and is further crushed into calcium carbide slag. The cooling air flow rate can be coordinated by the cooling air flow rate regulating valve 17 and the air preheater air inlet regulating valve 18 to ensure that there is always enough cooling air to solidify the calcium carbide liquid when the operating conditions change. After absorbing heat in the calcium carbide crusher 4, the cooling air is mixed with the hot air at the outlet of the air preheater 9 and then sent to the gas boiler 15 to support combustion.

[0035] The heat source medium of the carbide slag low-temperature heat exchanger 5 is the carbide slag from the carbide crusher 4 , and the cold source medium is the inert gas in the low-temperature inert gas circulation system 8 .

[0036] After the inert gas in the closed cycle absorbs heat in the calcium carbide liquid high-temperature heat exchanger 3, the temperature rises from 600-800°C to 1500-1700°C and enters the steam reheater 13 for heat exchange.

[0037] The heat source medium of the steam reheater 13 is high-temperature inert gas, and the cold source medium is steam from the outlet of the steam turbine high-pressure cylinder 16-1; the steam is heated by heat exchange and sent to the steam turbine low-pressure cylinder 16-2 for power generation, and the inert gas is cooled by heat exchange and sent to the calcium carbide liquid high-temperature heat exchanger 3 for heat absorption.

[0038] After the inert gas in the closed cycle absorbs heat in the carbide slag low-temperature heat exchanger 5, the temperature rises from 50-100°C to 300-400°C and enters the air preheater 9 for heat exchange.

[0039] The heat source medium of the air preheater 9 is high-temperature inert gas, and the cold source medium is air from the boiler blower 10; the air is heated by heat exchange and sent to the gas boiler 15 to support combustion, and the inert gas is cooled by heat exchange and sent to the calcium carbide slag low-temperature heat exchanger 5 to absorb heat.

[0040] The gas boiler 15 receives the calcium carbide tail gas after cooling, purification and pressurization from the calcium carbide tail gas treatment system 14 as fuel, and at the same time receives hot air from the air preheater 9, burns and generates steam that enters the steam turbine 16 to generate power.

[0041] In summary, the present invention achieves efficiency improvement of the calcium carbide furnace-gas boiler coupled power generation system by using the high temperature section to reheat steam and the low temperature section to preheat air through graded utilization of calcium carbide waste heat. In addition, the system uses an inert gas closed cycle as a heat transfer medium to prevent chemical reactions between calcium carbide and air and water, thereby improving the safety of the system.

Claims

1. A calcium carbide waste heat coupled gas boiler power generation system, characterized in that: It comprises a calcium carbide furnace (1), a calcium carbide liquid high-temperature heat exchanger (3), a calcium carbide crusher (4), a calcium carbide slag low-temperature heat exchanger (5), a low-temperature inert gas circulation system (8), an air preheater (9), a boiler blower (10), a high-temperature inert gas circulation system (12), a steam reheater (13), a calcium carbide tail gas treatment system (14), a gas boiler (15) and a steam turbine (16); The exhaust gas outlet of the calcium carbide furnace (1) is connected to the inlet of the calcium carbide tail gas treatment system (14), and the air outlet of the calcium carbide tail gas treatment system (14) is connected to the gas boiler (15); The liquid outlet of the calcium carbide furnace (1) is connected to the inlet of the calcium carbide liquid high-temperature heat exchanger (3), the high-temperature inert gas circulation system (12) is connected to the calcium carbide liquid high-temperature heat exchanger (3) and the steam reheater (13), the high-temperature inert gas circulation system (12) can transfer heat in the calcium carbide liquid high-temperature heat exchanger (3) to the steam reheater (13), the steam reheater (13) is connected to the steam turbine (16), and the steam turbine (16) is connected to the gas boiler (15); The liquid outlet of the calcium carbide liquid high-temperature heat exchanger (3) is connected to the molten calcium carbide liquid inlet of the calcium carbide crusher (4); the air outlet of the boiler blower (10) is divided into two paths, one of which is connected to the air preheater (9) and the other is connected to the cooling air inlet of the calcium carbide crusher (4) and cools and solidifies the molten calcium carbide liquid entering the calcium carbide crusher (4); the air outlet of the calcium carbide crusher (4) is connected to the air outlet of the air preheater (9); The outlet of the carbide crusher (4) is connected to the carbide slag inlet of the carbide slag low-temperature heat exchanger (5), the low-temperature inert gas circulation system (8) is connected to the carbide slag low-temperature heat exchanger (5) and the air preheater (9), and the low-temperature inert gas circulation system (8) is used to transfer heat in the carbide slag low-temperature heat exchanger (5) to the air preheater (9); An air preheater air inlet regulating valve (18) is provided along the path connecting the air outlet of the boiler blower (10) and the air preheater (9); A cooling air flow regulating valve (17) is provided on the path connecting the air outlet of the boiler blower (10) and the calcium carbide crusher (4).

2. The calcium carbide waste heat coupled gas boiler power generation system according to claim 1 is characterized in that: The liquid outlet of the calcium carbide furnace (1) is provided with a calcium carbide pot (2) for containing molten calcium carbide liquid, and the liquid outlet of the calcium carbide pot (2) is connected to the inlet of the calcium carbide liquid high-temperature heat exchanger (3).

3. The calcium carbide waste heat coupled gas boiler power generation system according to claim 1 is characterized in that: The high-temperature inert gas circulation system (12) is a closed cycle and is equipped with a high-temperature inert gas circulation fan (11).

4. The calcium carbide waste heat coupled gas boiler power generation system according to claim 1 is characterized in that: The low-temperature inert gas circulation system (8) is a closed cycle and is equipped with a low-temperature inert gas circulation fan (7).

5. The calcium carbide waste heat coupled gas boiler power generation system according to claim 1 is characterized in that: The slag outlet of the carbide slag low-temperature heat exchanger (5) is connected to the carbide slag recovery device (6).

6. The calcium carbide waste heat coupled gas boiler power generation system according to claim 1 is characterized in that: The cold inlet of the steam reheater (13) is connected to the outlet of the high-pressure cylinder (16-1) of the steam turbine, and the hot outlet of the steam reheater (13) is connected to the low-pressure cylinder (16-2) of the steam turbine.

7. A method for generating electricity by coupling calcium carbide waste heat with a gas boiler, characterized in that: The method is carried out using the stone waste heat coupled gas boiler power generation system according to any one of claims 1 to 6, and the method includes the following process: The combustible waste gas generated in the calcium carbide furnace (1) is discharged from the top thereof, enters the calcium carbide tail gas treatment system (14), and is then sent to the gas boiler (15) for combustion; The molten calcium carbide liquid in the calcium carbide furnace (1) is discharged into the calcium carbide liquid high-temperature heat exchanger (3), and the high-temperature inert gas circulation system (12) transfers the heat of the molten calcium carbide liquid in the calcium carbide liquid high-temperature heat exchanger (3) to the steam reheater (13); the steam reheater (13) heats the steam and then sends it to the steam turbine (16) for power generation; The molten calcium carbide liquid cooled by heat exchange in the calcium carbide liquid high-temperature heat exchanger (3) enters the calcium carbide crusher (4), and the cooling air sent in by the boiler blower (10) exchanges heat with the molten calcium carbide liquid to cool and solidify the molten calcium carbide liquid. The heated air after heat exchange is combined with the outlet air of the air preheater (9) and sent to the gas boiler (15) for combustion. The calcium carbide crusher (4) crushes the solidified calcium carbide into slag. The calcium carbide slag processed in the calcium carbide crusher (4) enters the calcium carbide slag low-temperature heat exchanger (5), and the low-temperature inert gas circulation system (8) exchanges the heat in the calcium carbide slag low-temperature heat exchanger (5) to the air preheater (9).

8. The method for generating electricity by coupling calcium carbide waste heat with a gas boiler according to claim 7 is characterized in that: After the inert gas in the high-temperature inert gas circulation system (12) absorbs heat in the calcium carbide liquid high-temperature heat exchanger (3), the temperature rises from 600~800°C to 1500~1700°C; after the inert gas in the low-temperature inert gas circulation system (8) absorbs heat in the calcium carbide slag low-temperature heat exchanger (5), the temperature rises from 50~100°C to 300~400°C.

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