System for recycling sensible heat of calcium carbide furnace gas for ORC power generation

Abstract

The utility model discloses a system for recovering sensible heat of calcium carbide furnace gas for ORC power generation, which belongs to the field of waste heat recovery and comprises a calcium carbide furnace gas waste heat recovery system and an ORC organic Rankine cycle power generation system. In the calcium carbide furnace gas waste heat recovery system, the gas outlet end of a calcium carbide furnace, the gas side of a first heat pipe waste heat boiler, a dust remover and the gas side of a second heat pipe waste heat boiler are sequentially connected; the steam-water side of the evaporator, the condensate pump, the water tank, the feed pump, the steam-water side of the second heat pipe waste heat boiler and the steam pocket are sequentially connected; the steam pocket is connected with the steam-water side of the first heat pipe waste heat boiler; the organic working medium side of the evaporator, the expansion machine, the condenser and the working medium pump are sequentially connected; an output shaft of the expansion machine is connected with a driving shaft of the generator. On the basis that the existing production process is not changed, energy conservation and emission reduction can be achieved, the coal gas temperature can be stably reduced, implementation is easy, production is facilitated, and meanwhile the production and use cost is greatly reduced.

Description

Technical Field

[0001] The utility model relates to the field of waste heat recovery, in particular to a system for recovering the sensible heat of carbide furnace gas for ORC power generation. Background Technique

[0002] Calcium carbide, also known as silicon carbide CaC2, is one of the basic raw materials of the chemical industry and is also called the mother of chemical raw materials. For every ton of calcium carbide produced, about 400 Nm3 of by-product gas is generated. The main components of the gas are CO and H2. The gas is a high-temperature gas, generally at a temperature of 400-600 °C, and the dust content is generally 100 g / m3. Usually, a multi-stage surface air cooler is used to reduce the temperature of the high-temperature gas to below 200 °C before entering the bag filter. The surface air cooler is placed in the atmospheric environment, which is equivalent to dissipating the sensible heat of the high-temperature gas into the atmospheric environment, resulting in a great waste of energy. A heat pipe waste heat boiler is composed of several special heat pipe elements. The heating section of the heat pipe is placed in the waste gas duct, and the hot air sweeps across the heating section of the heat pipe. The heat release section of the heat pipe element is inserted into the water-steam system. Due to the existence of the heat pipe, the heating and circulation of the water-steam system are completely separated from the heat source and exist independently outside the waste gas duct. The water-steam system is not directly scoured by the hot fluid, so the heat release section of the heat pipe element is not easily damaged.

[0003] Existing carbide furnace gas waste heat recovery, such as the carbide furnace tail gas waste heat boiler with the application number 201320793752.9, uses a waste heat boiler to produce low-pressure saturated steam; the carbide furnace flue gas waste heat utilization system with the application number 201320789699.5 uses a heat pipe heat exchanger to produce steam for steam turbine power generation; a carbide furnace flue gas purification and waste heat recovery integrated treatment system with the application number 202221608402.6 uses a series of equipment such as a rising cooling flue, a falling cooling flue, an evaporator, and a water preheater to reduce the flue gas temperature to 50-80 °C; a heat pipe heat exchanger with the application number 201320797482.9 uses an inner and outer sleeve structure, with water flowing through the inner cylinder and gas flowing through the jacket between the inner and outer cylinders, which can be used to recover the waste heat of carbide furnace tail gas, etc., and all can recover waste heat, but the effect of waste heat recovery and utilization is not ideal, and the waste heat cannot be fully utilized reasonably. Content of the Utility Model

[0004] Regarding the above problems existing in the prior art, the purpose of the present utility model is to provide a system for recovering the sensible heat of carbide furnace gas for ORC power generation to solve the problems raised in the above background technique.

[0005] To achieve the above object, the present utility model provides the following technical solutions:

[0006] A system for recovering the sensible heat of carbide furnace gas for ORC power generation, comprising a carbide furnace gas waste heat recovery system and an ORC organic Rankine cycle power generation system; the carbide furnace gas waste heat recovery system includes a carbide furnace, a first heat pipe waste heat boiler, a steam drum, a dust collector, a second heat pipe waste heat boiler, a feed water pump, a water tank and a condensate pump;

[0007] The gas outlet end of the carbide furnace is connected to the gas side inlet end of the first heat pipe waste heat boiler through a pipeline, the gas side outlet end of the first heat pipe waste heat boiler is connected to the input end of the dust collector through a pipeline, and the output end of the dust collector is connected to the inlet end of the gas side of the second heat pipe waste heat boiler through a pipeline;

[0008] The ORC organic Rankine cycle power generation system includes an evaporator. The output end of the steam-water side of the evaporator is connected to the input end of the condensate pump through a pipeline. The output end of the condensate pump is connected to the input end of the water tank through a pipeline. The output end of the water tank is connected to the input end of the feed water pump through a pipeline. The output end of the feed water pump is connected to the steam-water side input end of the second heat pipe waste heat boiler through a pipeline. The steam-water side output end of the second heat pipe waste heat boiler is connected to the input end of the steam drum through a pipeline. The output end of the steam drum is connected to the input end of the steam-water side of the evaporator through a pipeline;

[0009] The downcomer at the bottom of the steam drum is connected to the steam-water side input end of the first heat pipe waste heat boiler; the riser at the top of the steam drum is connected to the steam-water side output end of the first heat pipe waste heat boiler;

[0010] The output end of the organic working fluid side of the evaporator is connected to the inlet of the expander. The outlet of the expander is connected to one end of the condenser. The other end of the condenser is connected to the input end of the working fluid pump. The output end of the working fluid pump is connected to the input end of the organic working fluid side of the evaporator;

[0011] The output shaft of the expander is connected to the drive shaft of the generator.

[0012] As a further solution of the present utility model: the heat pipes in the first heat pipe waste heat boiler and the second heat pipe waste heat boiler are finned heat pipes.

[0013] As a further solution of the present utility model: the furnace bottoms of the first heat pipe waste heat boiler and the second heat pipe waste heat boiler are provided with funnel-shaped ash hoppers.

[0014] As a further solution of the present utility model: the input end of the water tank is arranged at the top of the water tank, and the output end of the water tank is arranged at the bottom of the water tank.

[0015] As a further solution of the present utility model: the output end of the generator is connected to the power grid.

[0016] Compared with the prior art, the beneficial effects of the present utility model are:

[0017] The utility model can, without changing the existing production process, recover the sensible heat of the carbide furnace gas by paralleling the carbide furnace gas waste heat recovery system and the ORC organic Rankine cycle power generation system, reducing the sensible heat of the carbide furnace gas from about 600 °C to about 120 °C, achieving energy conservation and emission reduction, being beneficial to stabilizing the gas temperature at the inlet of the subsequent dust collector, and using a heat pipe waste heat boiler to greatly avoid the influence of the heat receiving section of the heat pipe damaged by the gas scouring on the stable operation of the system; the system has reasonable process design, is easy to implement, is beneficial to production, and greatly reduces the production cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a system structure diagram of a system for recovering the sensible heat of carbide furnace gas for ORC power generation disclosed in the embodiment.

[0019] In the figure, the reference numerals are: 1, carbide furnace; 2, first heat pipe waste heat boiler; 3, steam drum; 4, dust collector; 5, second heat pipe waste heat boiler; 6, feed water pump; 7, water tank; 8, condensate pump; 9, evaporator; 10, expander; 11, generator; 12, condenser; 13, working fluid pump. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model; obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present utility model.

[0021] In the description of the present utility model, it should be noted that, unless otherwise clearly defined and limited, the terms "installed", "provided with", "connected", and "connected" should be understood in a broad sense; for example, it can be a fixed connection, a detachable connection, or an integral connection, it can be a mechanical connection, an electrical connection, it can be directly connected, or indirectly connected through an intermediate medium, and it can be the internal communication of two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific situations.

[0022] Please refer to Figure 1 , a system for recovering the sensible heat of carbide furnace gas for ORC power generation, including a carbide furnace gas waste heat recovery system and an ORC organic Rankine cycle power generation system; the carbide furnace gas waste heat recovery system includes a carbide furnace 1, a first heat pipe waste heat boiler 2, a steam drum 3, a dust collector 4, a second heat pipe waste heat boiler 5, a feed water pump 6, a water tank 7, and a condensate pump 8;

[0023] The gas outlet end of the calcium carbide furnace 1 is connected to the gas-side inlet end of the first heat pipe waste heat boiler 2 through a pipeline. The gas-side outlet end of the first heat pipe waste heat boiler 2 is connected to the input end of the pipeline dust collector 4. The output end of the dust collector 4 is connected to the gas-side inlet end of the second heat pipe waste heat boiler 5 through a pipeline. The gas generated by the calcium carbide furnace 1 flows through the first heat pipe waste heat boiler 2, the dust collector 4, and the second heat pipe waste heat boiler 5 in sequence through the pipeline.

[0024] The ORC organic Rankine cycle power generation system includes an evaporator 9. The output end of the steam-water side of the evaporator 9 is connected to the input end of the condensate pump 8 through a pipeline. The output end of the condensate pump 8 is connected to the top input end of the water tank 7 through a pipeline. The bottom output end of the water tank 7 is connected to the input end of the feed water pump 6 through a pipeline. The output end of the feed water pump 6 is connected to the steam-water side input end of the second heat pipe waste heat boiler 5 through a pipeline. The steam-water side output end of the second heat pipe waste heat boiler 5 is connected to the input end of the steam drum 3 through a pipeline. The output end of the steam drum 3 is connected to the steam-water side input end of the evaporator 9 through a pipeline. The steam-water side of the evaporator 9, the condensate pump 8, the water tank 7, the feed water pump 6, the steam-water side of the second heat pipe waste heat boiler 5, and the steam drum 3 form a closed cycle, and the water vapor forms a closed cycle. The water / water vapor flows through the above-mentioned equipment in sequence.

[0025] The downcomer at the bottom of the steam drum 3 is connected to the steam-water side input end of the first heat pipe waste heat boiler 2. The riser at the top of the steam drum 3 is connected to the steam-water side output end of the first heat pipe waste heat boiler 2. The steam-water side of the steam drum 3 and the first heat pipe waste heat boiler 2 form a closed cycle through the downcomer and the riser.

[0026] The output end of the organic working fluid side of the evaporator 9 is connected to the inlet of the expander 10. The outlet of the expander 10 is connected to one end of the condenser 12. The other end of the condenser 12 is connected to the input end of the working fluid pump 13. The output end of the working fluid pump 13 is connected to the organic working fluid side input end of the evaporator 9.

[0027] The output shaft of the expander 10 is connected to the drive shaft of the generator 11. The output end of the generator 11 is connected to the power grid.

[0028] The waste heat in the tail gas generated by the calcium carbide furnace 1 conveniently heats the water flowing out of the water tank 7 into water vapor, which is transmitted to the evaporator 9 to heat the organic working fluid of the evaporator 9. After heating, the water vapor condenses into water and flows back to the water tank 7. After heating, the organic working fluid enters the expander 10, and electricity is generated through the coordinated work of the expander 10 and the generator 11, and then the electricity is transmitted to the power grid. The temperature of the organic working fluid passing through the expander 10 will decrease, and the temperature of the organic working fluid is further reduced through the condenser 12 and then flows back to the evaporator 9 for recycling.

[0029] The heat pipes in the first heat pipe waste heat boiler 2 and the second heat pipe waste heat boiler 5 are finned heat pipes; due to the scouring of the gas, local damage occurs in the heated section of the heat pipes in the heat pipe waste heat boiler, which does not affect the normal operation of the system and can be repaired or replaced during the major overhaul.

[0030] The bottoms of the first heat pipe waste heat boiler 2 and the second heat pipe waste heat boiler 5 are provided with funnel-shaped ash hoppers for the settlement of dust; the valves below the ash hoppers can be opened regularly to remove the dust, or a compressed air pipeline can be set up to convey the dust away. The gas contains dust, which may adhere to the outer surface of the heat pipes, so it is necessary to clean the ash regularly, such as using a shock wave ash cleaner.

[0031] The temperature of the gas generated from the calcium carbide furnace 1 is about 400 - 600 °C. After entering the first heat pipe waste heat boiler 2, the temperature drops to about 200 °C, then after entering the dust removal equipment 4, the temperature decreases somewhat, and after entering the second heat pipe waste heat boiler 5, the temperature can drop to about 110 °C.

[0032] The heat transfer medium used in the organic Rankine cycle process is an organic working fluid. Controlling the temperature of the steam produced at the outlet of the steam drum 3 at 120 - 150 °C can effectively prevent the chemical decomposition of the organic working fluid. The ORC organic Rankine cycle power generation technology can recover and utilize medium and low temperature waste heat resources for power generation, converting low-grade heat energy into high-grade electrical energy, which is an effective technical path for recovering medium and low temperature waste heat resources. Therefore, adopting the heat pipe waste heat boiler + ORC organic Rankine cycle power generation technology to recover the sensible heat of the calcium carbide furnace gas is an effective way to improve energy utilization efficiency, save energy and reduce pollutant emissions.

[0033] The utility model can, on the basis of not changing the existing production process, connect the evaporator of the calcium carbide furnace gas waste heat recovery system in parallel with the ORC organic Rankine cycle power generation system. The sensible heat of the calcium carbide furnace gas is collected by the heat pipe waste heat boiler to generate saturated steam, and then converted into high-quality electrical energy through the ORC organic Rankine cycle power generation technology. Through the calcium carbide furnace gas waste heat recovery system and the ORC power generation system, the sensible heat of the calcium carbide furnace gas is recovered from about 600 °C to about 120 °C, achieving energy conservation and emission reduction, which is beneficial to stabilizing the gas temperature at the inlet of the subsequent dust collector. Using the heat pipe waste heat boiler greatly avoids the influence of the damaged heated section of the heat pipe caused by gas scouring on the stable operation of the system; the system has a reasonable process design, is easy to implement and is beneficial to production.

[0034] For those skilled in the art, it is obvious that the present utility model is not limited to the details of the above-described exemplary embodiments, and the present utility model can be implemented in other specific forms without departing from the spirit or basic characteristics of the present utility model. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present utility model is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be embraced within the present utility model, and any reference signs in the claims should not be regarded as limiting the claims involved.

[0035] In addition, it should be understood that although this specification is described in terms of embodiments, not every embodiment only contains an independent technical solution. This narrative manner of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A system for recovering sensible heat of calcium carbide furnace gas for ORC power generation, characterized in that: It comprises a calcium carbide furnace gas waste heat recovery system and an ORC organic Rankine cycle power generation system; the calcium carbide furnace gas waste heat recovery system comprises a calcium carbide furnace (1), a first heat pipe waste heat boiler (2), a steam drum (3), a dust collector (4), a second heat pipe waste heat boiler (5), a feed water pump (6), a water tank (7) and a condensate pump (8); The gas outlet of the calcium carbide furnace (1) is connected to the gas inlet of the first heat pipe waste heat boiler (2) through a pipeline, the gas outlet of the first heat pipe waste heat boiler (2) is connected to the input end of the pipeline dust collector (4), and the output end of the dust collector (4) is connected to the gas inlet of the second heat pipe waste heat boiler (5) through a pipeline; The ORC organic Rankine cycle power generation system comprises an evaporator (9), wherein the output end of the steam-water side of the evaporator (9) is connected to the input end of a condensate pump (8) through a pipeline, the output end of the condensate pump (8) is connected to the input end of a water tank (7) through a pipeline, the output end of the water tank (7) is connected to the input end of a feed water pump (6) through a pipeline, the output end of the feed water pump (6) is connected to the steam-water side input end of a second heat pipe waste heat boiler (5) through a pipeline, the steam-water side output end of the second heat pipe waste heat boiler (5) is connected to the input end of a steam drum (3) through a pipeline, and the output end of the steam drum (3) is connected to the steam-water side input end of the evaporator (9) through a pipeline; The downcomer at the bottom of the drum (3) is connected to the steam-water side input end of the first heat pipe waste heat boiler (2); the upcomer at the bottom of the drum (3) is connected to the steam-water side output end of the first heat pipe waste heat boiler (2); The output end of the organic working fluid side of the evaporator (9) is connected to the inlet of the expander (10), the outlet of the expander (10) is connected to one end of the condenser (12), the other end of the condenser (12) is connected to the input end of the working fluid pump (13), and the output end of the working fluid pump (13) is connected to the input end of the organic working fluid side of the evaporator (9); The output shaft of the expander (10) is connected to the drive shaft of the generator (11).

2. A system for recovering sensible heat of calcium carbide furnace gas for ORC power generation according to claim 1, characterized in that: The heat pipes in the first heat pipe waste heat boiler (2) and the second heat pipe waste heat boiler (5) are fin-type heat pipes.

3. A system for recovering sensible heat of calcium carbide furnace gas for ORC power generation according to claim 2, characterized in that: Funnel-shaped ash hoppers are provided at the bottoms of the first heat pipe waste heat boiler (2) and the second heat pipe waste heat boiler (5).

4. A system for recovering sensible heat of calcium carbide furnace gas for ORC power generation according to claim 3, characterized in that: The input end of the water tank (7) is arranged at the top end of the water tank (7), and the output end of the water tank (7) is arranged at the bottom end of the water tank (7).

5. A system for recovering sensible heat of calcium carbide furnace gas for ORC power generation according to claim 4, characterized in that: The output end of the generator (11) is connected to the power grid.

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