Dry quenching flue gas waste heat recovery and power circulation device based on inert gas working medium

Abstract

The utility model discloses a dry quenching flue gas waste heat recovery and power circulation device based on an inert gas working medium, and belongs to the technical field of coking production. The device comprises a dry quenching furnace, a primary dust remover, a secondary dust remover, a gas circulating fan, a high-temperature flue gas heat exchanger, a low-temperature flue gas heat exchanger, an auxiliary flue gas heat exchanger, a turbine, a heat regenerator, a precooler and a main compressor. According to the utility model, the high-temperature flue gas heat exchanger and the low-temperature flue gas heat exchanger which take inert gas as a working medium are used for sequentially exchanging heat for high-temperature flue gas of dry quenching, and the flue gas temperature at the inlet of the main flue gas heat exchanger is accurately controlled by adopting a dry quenching afterburning process technology, so that the characteristics of load fluctuation of dry quenching production can be obviously adapted; the inert gas working medium absorbing the waste heat is then used for the turbine to do work, the power circulation process with the inert gas as the working medium instead of water as the working medium is achieved, and the potential safety hazard of a dry quenching boiler system is solved.

Description

TECHNICAL FIELD

[0001] The utility model belongs to coking production technical field, concretely relates to a kind of dry quenching flue gas waste heat recovery and power cycle device based on inert gas working substance. BACKGROUND

[0002] Dry quenching waste heat power generation technology is to use nitrogen and other inert gases to cool coke in dry quenching furnace, and recover high-temperature flue gas heat from dry quenching furnace, and through dry quenching waste heat boiler to absorb heat and generate high-temperature and high-pressure steam, to send steam turbine generator set to generate electricity or industrial heating, to convert heat energy into electric energy and mechanical energy.

[0003] Traditional dry quenching process waste heat recovery is through dry quenching boiler heat exchange and drives steam turbine to generate electricity. Once dry quenching boiler fails, dry quenching production can only be stopped, and serious production failure or safety accident may occur. Solving the production accident of dry quenching boiler "pipe explosion" and minimizing the operation risk is a big technical problem in the current dry quenching industry. Secondly, the traditional dry quenching boiler power generation system uses water-steam as working medium for Rankine cycle. The key equipment of this system includes boiler, steam turbine generator set, condensate pump, deaerator, boiler feed water pump, etc., and supporting chemical water treatment equipment, circulating cooling water facilities or air cooling heat exchange equipment. It has the disadvantages of low power generation efficiency, long process, complex structure, poor unit peak shaving capacity, large space occupation, etc. In addition, due to the influence of coke oven coking and downstream coke screening and conveying system equipment, the non-planned start-stop machine has uncertainty, the dry quenching production fluctuates greatly, and often causes irreversible damage to the service life of dry quenching refractory materials and boiler. Therefore, in order to solve the many drawbacks of traditional dry quenching production process and change the traditional dry quenching waste heat recovery process, it is the focus of current research to use higher power generation efficiency, more compact equipment and more safe and reliable production working medium.

[0004] In the prior art, a method for realizing maintenance without shutdown of dry quenching boiler is reported in Chinese patent CN106867549B. The method introduces a heat exchange device in the flue gas circulation system of original dry quenching furnace, primary dust collector, dry quenching boiler, secondary dust collector, gas circulation fan and feed water preheater. When the dry quenching process system is in normal production, the heat exchange device does not participate in dry quenching production. When the dry quenching boiler needs to be repaired, the dry quenching furnace is in normal operation, the dry quenching boiler is isolated from the dry quenching process system for repair, and the inert gas after primary dust removal is sent into the heat exchange device for heat exchange and then enters the secondary dust collector. The influence of dry quenching boiler maintenance shutdown on dry quenching production is avoided. However, this method can only temporarily solve the influence of dry quenching boiler shutdown on dry quenching production. The heat exchange device using water-steam as working medium still has the risk of "pipe explosion", and the drawbacks of dry quenching boiler steam power cycle generation have not been fundamentally solved. UTILITY MODEL CONTENTS

[0005] The utility model discloses a kind of inert gas working medium-based coke dry quenching flue gas waste heat recovery and power cycle device, the high-temperature flue gas heat exchanger and low-temperature flue gas heat exchanger of inert gas as working medium are utilized by the device, high-temperature flue gas of coke dry quenching is sequentially heat exchanged, can significantly adapt to the characteristics of coke dry quenching production load fluctuation, inert gas working medium after absorbing waste heat is used in turbine again, realize inert gas as working medium to replace water as working medium power cycle process, solve the security risk of coke dry quenching boiler system.

[0006] The utility model discloses a kind of inert gas working medium-based coke dry quenching flue gas waste heat recovery and power cycle device, including dry quenching furnace, primary dust collector and secondary dust collector, further including high-temperature flue gas heat exchanger, low-temperature flue gas heat exchanger, vice flue gas heat exchanger, turbine, regenerator, pre-cooler and main compressor,

[0007] The dry quenching furnace, primary dust collector, high-temperature flue gas heat exchanger, low-temperature flue gas heat exchanger, secondary dust collector and vice flue gas heat exchanger are sequentially connected, and the vice flue gas heat exchanger is connected to the dry quenching furnace.

[0008] The turbine, regenerator, pre-cooler and main compressor are sequentially connected, the high-temperature flue gas heat exchanger, low-temperature flue gas heat exchanger and vice flue gas heat exchanger all use inert gas as working medium, the gas inlet of turbine is connected to the working medium outlet of high-temperature flue gas heat exchanger, the gas outlet of turbine is connected to the hot side of regenerator, two circulating pipelines are provided on the gas outlet of main compressor, one circulating pipeline is connected to the working medium inlet of high-temperature flue gas heat exchanger through the cold side of regenerator, and the other circulating pipeline is sequentially connected to the working medium inlet of high-temperature flue gas heat exchanger through vice flue gas heat exchanger and low-temperature flue gas heat exchanger.

[0009] A temperature and pressure reducing device is arranged between the working medium outlet of the high-temperature flue gas heat exchanger and the pre-cooler, and a compressor is arranged between the pre-cooler and the vice flue gas heat exchanger.

[0010] A fuel supply mechanism for adjusting the temperature of flue gas is arranged between the dry quenching furnace and the primary dust collector, and a flue gas temperature sensor is arranged in front of the flue gas inlet of the high-temperature flue gas heat exchanger.

[0011] The high-temperature flue gas heat exchanger and the low-temperature flue gas heat exchanger are arranged in an up-down manner.

[0012] The bottom of the primary dust collector and the secondary dust collector is respectively connected to the inlet of a gas ash conveying device, and the outlet of the gas ash conveying device is connected to an ash bin.

[0013] A gas circulating fan is arranged between the secondary dust collector and the vice flue gas heat exchanger.

[0014] The vice flue gas heat exchanger is connected to the cooling chamber of the dry quenching furnace.

[0015] It should be noted that the inert gas working medium includes but is not limited to carbon dioxide gas, helium and the like.

[0016] Compared with the prior art, the present application has the following advantages and beneficial effects:

[0017] (1) The present application adopts dry quenching combustion supplement process technology, and the inlet temperature of the high-temperature flue gas heat exchanger in the system can be improved and stabilized by the fuel supply mechanism, so that the flue gas temperature is stabilized at 950-1000 DEG C, and the dry quenching production load fluctuation is smaller, and the equipment thermal efficiency is precisely controlled and improved.

[0018] (2) The present application utilizes the inert gas working medium to heat the high-temperature flue gas heat exchanger, the low-temperature flue gas heat exchanger and the auxiliary flue gas heat exchanger, realizes the process flow of the inert gas working medium as a new type of power cycle generation or other industrial driving system applied in the dry quenching waste heat recovery system, and the high-temperature flue gas heat exchanger and the low-temperature flue gas heat exchanger arranged in upper and lower positions can reduce the equipment floor area, so that the overall device has the characteristics of simple structure, short process chain, high recovery thermal efficiency and significant adaptation to dry quenching production load fluctuation.

[0019] (3) The present application circulates the inert gas working medium in the dry quenching flue gas heat exchanger, obviously reduces the explosion, combustion and other serious accidents caused by the dry quenching furnace and the dust removal system after the traditional boiler pipe of the dry quenching is exploded, has small influence range and makes the dry quenching production more safe.

[0020] (4) The present application designs a temperature and pressure reducing device in the power cycle system with the inert gas as the working medium, fully considers the characteristics of the dry quenching production, and when the main equipment such as the turbine unit and the main compressor fails or is overhauled, the high-temperature and high-pressure inert gas working medium can be reduced in temperature and pressure to low-temperature and low-pressure gas working medium entering the pre-cooler, and then the working medium circulation is realized through the standby compressor, so that the continuity of the dry quenching production is ensured.

[0021] (5) The primary dust collector of the present application adopts the dust collector based on the cyclone separation principle, improves the dust removal efficiency and reduces the pipe wear risk of the dry quenching main flue gas heat exchanger. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 It is a process flow schematic diagram of the present application system.

[0023] Among them, 1 is a dry quenching furnace, 2 is a primary dust collector, 3 is a high-temperature flue gas heat exchanger, 4 is a low-temperature flue gas heat exchanger, 5 is a secondary dust collector, 6 is an auxiliary flue gas heat exchanger, 7 is a turbine, 8 is a regenerator, 9 is a pre-cooler, 10 is a main compressor, 11 is a temperature and pressure reducing device, 12 is a standby compressor, 13 is a fuel supply mechanism, 14 is a gas ash conveying device, 15 is an ash bin, and 16 is a gas circulating fan. DETAILED DESCRIPTION

[0024] The utility model will be further explained in detail in combination with the embodiments, but the implementation mode of the utility model is not limited to this.

[0025] Embodiment 1:

[0026] This embodiment is a kind of inert gas working medium-based coke dry quenching flue gas waste heat recovery and power cycle device. Referring to the structure shown in Figure 1, the device mainly includes two circulation routes, flue gas waste heat recovery cycle and inert gas working medium power cycle. Figure 1

[0027] In the flue gas waste heat recovery cycle, it includes primary dust collector 2, high-temperature flue gas heat exchanger 3, low-temperature flue gas heat exchanger 4, secondary dust collector 5 and auxiliary flue gas heat exchanger 6 connected in turn, primary dust collector 2 is connected to the flue gas pipeline of dry quenching furnace 1, auxiliary flue gas heat exchanger 6 is connected to the cooling chamber of dry quenching furnace 1. Among them, high-temperature flue gas heat exchanger 3, low-temperature flue gas heat exchanger 4 all take inert gas as working medium, inert gas working medium can be supercritical carbon dioxide gas, carbon dioxide gas or helium.

[0028] In this embodiment, the process flow of flue gas waste heat recovery cycle is as follows:

[0029] Dry quenching furnace 1-primary dust collector 2-high-temperature flue gas heat exchanger 3-low-temperature flue gas heat exchanger 4-secondary dust collector 5-gas circulating fan 16-auxiliary flue gas heat exchanger 6-dry quenching furnace 1.

[0030] Specifically, dry quenching furnace 1 sends high-temperature flue gas into primary dust collector 2, after removing particulate impurities, flue gas passes through high-temperature flue gas heat exchanger 3 and low-temperature flue gas heat exchanger 4 twice to release heat, and then enters secondary dust collector 5, after secondary dust collector 5 captures smaller particles of dust in flue gas, gas circulating fan 16 is used to send flue gas into auxiliary flue gas heat exchanger 6, flue gas temperature is further reduced, and finally sent into the cooling chamber of dry quenching furnace 1, to realize flue gas waste heat recovery cycle.

[0031] In specific application, the bottom of primary dust collector 2 and secondary dust collector 5 can be connected to the inlet of gas ash conveying device 14 respectively, and the outlet of gas ash conveying device 14 is connected to ash bin 15, to realize the collection of particulate impurities and dust in flue gas. Fuel supply mechanism 13 for adjusting flue gas temperature can also be arranged on the flue gas pipeline of dry quenching furnace 1, and flue gas temperature sensor is arranged before the flue gas inlet of high-temperature flue gas heat exchanger 3, which can detect the temperature of flue gas sucked into high-temperature flue gas heat exchanger 3, and when dry quenching production load fluctuates, fuel supply mechanism 13 can be controlled according to the detected temperature, to stabilize the temperature of sucked flue gas in the preset temperature range, such as 950-1000℃. Figure 1 ​The fuel supply mechanism 13 shown in the figure is only a simple schematic, in specific applications, the fuel supply mechanism 13 usually includes a gas fuel pipe, an ignition device and the like to ensure the adjustment of the flue gas temperature when the gas is burned.

[0032] In the inert gas working medium power cycle, including sequentially connected turbine 7, regenerator 8, pre-cooler 9 and main compressor 10, the gas inlet of turbine 7 is connected to the working medium outlet of the main flue gas heat exchanger, the gas outlet of turbine 7 is connected to the hot side of regenerator 8, and the gas outlet of main compressor 10 is provided with two circulating pipelines, one of which is connected to the working medium inlet of high-temperature flue gas heat exchanger 3 through the cold side of regenerator 8, and the other is connected to the working medium inlet of high-temperature flue gas heat exchanger 3 through vice flue gas heat exchanger 6 and low-temperature flue gas heat exchanger 4 in sequence.

[0033] In normal production, the working process of the inert gas working medium power cycle is as follows:

[0034] a. High-temperature and high-pressure inert gas working medium - turbine 7 - regenerator 8 (hot side) - pre-cooler 9 - main compressor 10 - regenerator 8 (cold side) - high-temperature flue gas heat exchanger 3 - high-temperature and high-pressure inert gas working medium;

[0035] b. High-temperature and high-pressure inert gas working medium - turbine 7 - regenerator 8 (hot side) - pre-cooler 9 - main compressor 10 - vice flue gas heat exchanger 6 - low-temperature flue gas heat exchanger 4 - high-temperature flue gas heat exchanger 3 - high-temperature and high-pressure inert gas working medium.

[0036] Specifically, the high-temperature flue gas from the once-through dust collector 2 of the dry quenching furnace 1 first enters the high-temperature flue gas heat exchanger 3, which uses inert gas working medium for heat exchange, and obtains high-temperature and high-pressure inert gas working medium, which is discharged from the outlet of the high-temperature flue gas heat exchanger 3 and connected to the turbine 7 for power generation or other industrial driving. The inert gas working medium is adiabatically expanded in the turbine 7 to do work, and the working medium pressure and temperature are reduced, and then enters the regenerator 8 through the pipeline, and exchanges heat with the countercurrent cold side inert gas working medium, so that the cold side working medium temperature is raised and the heat of the hot side working medium is utilized. The working medium after heat exchange in the regenerator 8 enters the pre-cooler 9 and is cooled by external cooling water or air, and then obtains low-temperature and low-pressure inert gas working medium, which is then sent to the main compressor 10 for pressure increase, and obtains high-pressure and low-temperature inert gas working medium. Part of the high-pressure and low-temperature inert gas working medium flows into the regenerator 8 from the inlet of the cold side of the regenerator 8, absorbs heat, and then is sent to the high-temperature flue gas heat exchanger 3 through the outlet of the cold side of the regenerator 8, and is used for recovering the heat of the high-temperature flue gas. Another part of the high-pressure and low-temperature inert gas working medium is sent to the auxiliary flue gas heat exchanger 6 through the pipeline, absorbs the heat of the flue gas from the outlet of the gas circulating fan 16 in the auxiliary flue gas heat exchanger 6, and then enters the low-temperature flue gas heat exchanger 4, and the temperature of the inert gas working medium is further raised, and then is combined with the working medium from the outlet of the cold side of the regenerator 8, and finally enters the high-temperature heat exchanger, and the inert gas working medium reaches the high-temperature and high-pressure outlet parameters, and then enters the turbine 7 for power generation or other industrial driving.

[0037] In a specific embodiment, during normal operation, high-temperature flue gas at 950-1000°C enters the high-temperature flue gas heat exchanger 3, and the inert gas working medium discharged from the cold side outlet of the regenerator 8 has a temperature and pressure of about 240°C and 21.9 MPa. The working medium mixed with the working medium (having a temperature and pressure of about 240°C and 21.9 MPa) discharged from the outlet of the low-temperature flue gas heat exchanger 4 enters the high-temperature flue gas heat exchanger 3, exchanges heat with the high-temperature flue gas entering the high-temperature flue gas heat exchanger 3, and the inert gas working medium is heated to a temperature of 566°C or higher and a pressure of 21.9 MPa, and enters the turbine 7. The main compressor 10 sucks in low-temperature and low-pressure inert gas working medium (8 MPa, 35°C) and compresses it to obtain low-temperature and high-pressure inert gas working medium (22 MPa, 35°C). Part of the low-temperature and high-pressure inert gas working medium enters the secondary flue gas heat exchanger 6, absorbs heat from the dry quenching flue gas in the secondary flue gas heat exchanger 6, and the dry quenching flue gas has an outlet temperature of about 120°C. The working medium (104°C / 22 MPa) discharged from the outlet of the secondary flue gas heat exchanger 6 enters the low-temperature flue gas heat exchanger 4, exchanges heat with the flue gas, and the high-temperature and high-pressure working medium (240°C / 21.9 MPa) is mixed with part of the working medium (240°C / 21.9 MPa) from the regenerator 8, and then enters the high-temperature flue gas heat exchanger 3. The high-temperature flue gas after heat exchange in the high-temperature flue gas heat exchanger 3 has an outlet flue gas temperature of about 270°C, and the flue gas temperature is about 150°C after passing through the low-temperature flue gas heat exchanger 4, enters the dry quenching secondary dust collector 5, is pressurized by the gas circulating fan 16, and then enters the dry quenching furnace 1 after being cooled in the secondary flue gas heat exchanger 6.

[0038] Further, the present embodiment can solve the power circulation of the inert gas working medium during unit failure or overhaul by providing the temperature and pressure reducing device 11 and the standby compressor 12. The temperature and pressure reducing device 11 is arranged between the working medium outlet of the high-temperature flue gas heat exchanger 3 and the precooler 9, and the standby compressor 12 is arranged between the precooler 9 and the secondary flue gas heat exchanger 6. The inert gas working medium absorbing residual heat in the high-temperature flue gas heat exchanger 3 is sequentially sent to the temperature and pressure reducing device 11, the precooler 9, the standby compressor 12, the secondary flue gas heat exchanger 6, and then to the low-temperature flue gas heat exchanger 4, and finally to the high-temperature flue gas heat exchanger 3, thereby realizing the circulation of the inert gas working medium during dry quenching shutdown. The working process is as follows:

[0039] High-temperature and high-pressure inert gas working medium—temperature and pressure reducing device 11—precooler 9—standby compressor 12—secondary flue gas heat exchanger 6—low-temperature flue gas heat exchanger 4—high-temperature flue gas heat exchanger 3—high-temperature and high-pressure inert gas working medium.

[0040] Since dry quenching production must be continuous, dry quenching circulating flue gas is operated in a closed cycle system. When any equipment in the dry quenching system fails and stops, dry quenching needs to stop production. Therefore, the dry quenching flue gas heat exchanger needs to be very safe and reliable. The equipment in the new type of power cycle system using inert gas as the working medium also needs to be safe and reliable. Since dry quenching is mainly for quenching and auxiliary waste heat recovery, in order to ensure the safety temperature of the system, so that the equipment in the system can also ensure the continuous production of dry quenching when it fails or overhauls. The present embodiment specially designs a temperature and pressure reducing device 11, which can reduce the high temperature and high pressure inert gas to low temperature and low pressure gas working medium into the pre-cooler 9, and then realize the working medium cycle through the standby compressor 12.

[0041] The above is only a preferred embodiment of the present application, and does not limit the present application in any form. Any simple modification or equivalent change made according to the technical essence of the present application to the above embodiment falls within the protection scope of the present application.

Claims

1. A dry quenching flue gas waste heat recovery and power cycle device based on inert gas working medium, comprising a dry quenching furnace (1), a primary dust collector (2) and a secondary dust collector (5), characterized in that: It also includes a high-temperature flue gas heat exchanger (3), a low-temperature flue gas heat exchanger (4), a secondary flue gas heat exchanger (6), a turbine (7), a regenerator (8), a precooler (9), and a main compressor (10). The dry quenching furnace (1), primary dust collector (2), high-temperature flue gas heat exchanger (3), low-temperature flue gas heat exchanger (4), secondary dust collector (5) and auxiliary flue gas heat exchanger (6) are connected in sequence, and the auxiliary flue gas heat exchanger (6) is connected to the dry quenching furnace (1). The turbine (7), regenerator (8), precooler (9) and main compressor (10) are connected in sequence. The high-temperature flue gas heat exchanger (3), low-temperature flue gas heat exchanger (4) and auxiliary flue gas heat exchanger (6) all use inert gas as working fluid. The inlet of the turbine (7) is connected to the working fluid outlet of the high-temperature flue gas heat exchanger (3). The outlet of the turbine (7) is connected to the hot side of the regenerator (8). Two circulation pipelines are provided on the outlet of the main compressor (10). One circulation pipeline is connected to the working fluid inlet of the high-temperature flue gas heat exchanger (3) through the cold side of the regenerator (8). The other circulation pipeline is connected to the working fluid inlet of the high-temperature flue gas heat exchanger (3) through the auxiliary flue gas heat exchanger (6) and the low-temperature flue gas heat exchanger (4) in sequence.

2. The inert gas working fluid based coke dry quenching flue gas waste heat recovery and power cycle apparatus as claimed in claim 1 wherein: A de-heating and pressure reducing device (11) is provided between the working fluid outlet of the high-temperature flue gas heat exchanger (3) and the precooler (9), and a compressor (12) is provided between the precooler (9) and the auxiliary flue gas heat exchanger (6).

3. The inert gas working fluid based coke dry quenching flue gas waste heat recovery and power cycle apparatus as claimed in claim 1 wherein: A fuel supply mechanism (13) for adjusting flue gas temperature is provided between the dry quenching furnace (1) and the primary dust collector (2), and a flue gas temperature sensor is provided before the flue gas inlet of the high-temperature flue gas heat exchanger (3).

4. The inert gas working fluid based coke dry quenching flue gas waste heat recovery and power cycle apparatus as claimed in claim 1 wherein: The high-temperature flue gas heat exchanger (3) and the low-temperature flue gas heat exchanger (4) are arranged one above the other.

5. The inert gas working fluid based coke dry quenching flue gas waste heat recovery and power cycle apparatus as claimed in claim 1 wherein: The bottom of the primary dust collector (2) and the secondary dust collector (5) are respectively connected to the inlet of the gas ash conveying device (14), and the outlet of the gas ash conveying device (14) is connected to the ash silo (15).

6. The inert gas working fluid based coke dry quenching flue gas waste heat recovery and power cycle apparatus as claimed in claim 1 wherein: A gas circulation fan (16) is provided between the secondary dust collector (5) and the auxiliary flue gas heat exchanger (6).

7. The inert gas working fluid based coke dry quenching flue gas waste heat recovery and power cycle apparatus as claimed in claim 1 wherein: The auxiliary flue gas heat exchanger (6) is connected to the cooling chamber of the dry quenching furnace (1).

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