Combustion device and combustion system

Abstract

The utility model provides a combustion device and a combustion system, which relate to the field of chemical equipment. Gasified fine slag is introduced into a circulating fluidized combustion furnace for fluidized combustion. The bottom dense phase zone and the middle dilute phase zone of the circulating fluidized combustion furnace adopt an insulated furnace without water-cooled walls, and only the furnace body of the top dilute phase zone is provided with a water-cooled wall, which can ensure that the temperature of the gasified fine slag is maintained at a high level during combustion, thereby improving the stability of combustion; the residual carbon of the gasified fine slag after combustion in the circulating fluidized combustion furnace can be further fully burned in the reburner, thereby minimizing the carbon content of the fly ash and improving the combustion efficiency of the system.

Description

Technical Field

[0001] The utility model relates to the field of chemical equipment, in particular to a combustion device and a combustion system. Background Art

[0002] In recent years, in order to achieve the goal of "dual carbon", the transformation and upgrading of the coal industry has accelerated, and the solid waste emissions of coal gasification processes have increased significantly, resulting in a large amount of gasification fine slag. The open-air stacking and landfill treatment of a large amount of gasification fine slag will occupy land resources, cause environmental problems such as soil, water and dust pollution, and easily create safety hazards. Therefore, it is necessary to comprehensively treat and utilize gasification fine slag.

[0003] The carbon content of gasified fine slag is about 10%-30%, which is difficult to be used directly to make building materials. Due to the characteristics of high moisture content (50%-60%), low volatile matter (<5%), and low calorific value (600-2200kcal / kg), the combustion of gasified fine slag is difficult and unstable. Therefore, it is of great significance to develop a gasification system and method for gasified fine slag with low calorific value, fine particles, and high moisture content: it can fully utilize the calorific value of gasified fine slag to produce steam for power generation or heating; at the same time, the low carbon ash produced after combustion is easier to prepare building materials.

[0004] Existing suspension combustion furnaces are mostly suitable for fine-particle coal powder, which has the advantages of high combustion temperature and high burnout rate, but the moisture content of the fuel is generally not more than 20%, or even less than 10%, and the calorific value and volatile matter of the fuel cannot be too low (required to be higher than 4500Kcal / kg). The gasified fine slag with low calorific value is difficult to ignite in the coal powder combustion furnace, and self-stabilizing combustion cannot be achieved.

[0005] Existing circulating fluidized bed combustion furnaces have good adaptability to low calorific value fuels. However, circulating fluidized bed combustion furnaces require that the particle size of the fuel cannot be too small. The particle size of gasified fine slag is generally less than 0.1 mm, which is very easy to escape directly under the action of fluidizing wind and cause incomplete combustion.

[0006] In existing pulverized coal combustion furnaces or circulating fluidized bed combustion furnaces, membrane water-cooled walls are usually arranged from bottom to top to absorb heat and vaporize feed water. The water in the water-cooled walls in the fuel ignition and initial combustion areas absorbs a large amount of heat, which can easily lead to a decrease in furnace temperature and poor combustion stability when burning low calorific value fuels.

[0007] Therefore, there is an urgent need to improve the combustion equipment so that low calorific value fuels can burn stably in the furnace and meet the requirements of full combustion of the fuel.

[0008] In view of this, this application is hereby filed. Utility Model Content

[0009] The utility model aims to provide a combustion device and a combustion system, which can make low calorific value fuel burn more stably in a furnace and make full use of residual carbon in gasified fine slag.

[0010] The embodiment of the utility model is achieved as follows:

[0011] In a first aspect, the utility model provides a combustion device, including a circulating fluidized combustion furnace, a gas-solid separation device and a reburner, wherein the circulating fluidized combustion furnace is provided with a bottom dense phase zone, a middle dilute phase zone and a top dilute phase zone from bottom to top, and the circulating fluidized combustion furnace is provided with a water-cooled wall only on the furnace body of the top dilute phase zone;

[0012] A fluidized material feed port and a gasified fine slag feed port are provided in the middle dilute phase zone, and a flue gas outlet is provided in the top dilute phase zone. The flue gas outlet is connected to the inlet of the gas-solid separation device, the gas phase outlet of the gas-solid separation device is connected to the reburner, and the solid phase outlet of the gas-solid separation device is connected to the bottom dense phase zone of the circulating fluidized combustion furnace.

[0013] In an optional embodiment, it also includes a primary fan, a secondary fan, a first-level air preheater and a second-level air preheater, and the first-level air preheater and the second-level air preheater are both provided with a primary air preheating duct and a secondary air preheating duct. The gas output by the primary fan passes through the primary air preheating duct on the first-level air preheater and the primary air preheating duct on the second-level air preheater in sequence, and then is connected to the bottom dense phase area of ​​the circulating fluidized combustion furnace. The gas output by the secondary fan passes through the secondary air preheating duct on the first-level air preheater and the secondary air preheating duct on the second-level air preheater in sequence, and then is connected to the middle dilute phase area of ​​the circulating fluidized combustion furnace.

[0014] In an optional embodiment, a reburning fan and a reburning air preheater are further included, wherein the outlet of the reburning fan is connected to the inlet of the reburning air preheater, and the outlet of the reburning air preheater is connected to the reburner.

[0015] In an optional embodiment, a superheater and an economizer are also included, and the flue gas output from the flue gas outlet of the reburner is cooled and heat-exchanged through the superheater, the reburning air preheater, the economizer, the secondary air preheater and the primary air preheater in sequence.

[0016] In an optional embodiment, it also includes a flue gas purification device, an induced draft fan and a smoke exhaust device, the flue gas outlet on the first-stage air preheater is connected to the inlet of the flue gas purification device, the outlet of the flue gas purification device is connected to the inlet of the induced draft fan, and the outlet of the induced draft fan is connected to the smoke exhaust device.

[0017] In an optional embodiment, a steam drum is also included, and an external feed water inlet and an external feed water outlet are provided on the economizer, the external feed water outlet is connected to the steam drum, the bottom outlet of the steam drum is connected to the bottom inlet of the water-cooled wall on the top dilute phase zone, and the top outlet of the water-cooled wall is connected to the steam drum.

[0018] In an optional embodiment, the top outlet of the steam drum is connected to a superheater, and the steam outlet of the superheater is connected to a steam turbine.

[0019] In an optional embodiment, it also includes a return device and a return fan, the return device has a feed chamber and a return chamber connected to the feed chamber, the feed chamber is connected to the solid phase outlet of the gas-solid separation device, the return chamber is connected to the bottom dense phase area of ​​the circulating fluidized combustion furnace, and the feed chamber and the return chamber are both connected to the return fan.

[0020] In an optional embodiment, the furnace body of the bottom dense phase zone and the middle rarefied phase zone is formed of high temperature refractory material;

[0021] It also includes a gasification fine slag feeding device and a fluidized material feeding device. The gasification fine slag feeding device is connected to the gasification fine slag feed port, and the fluidized material feeding device is connected to the fluidized material feed port. The fluidized material feed port is located above the gasification fine slag feed port.

[0022] In a second aspect, the utility model provides a combustion system, comprising a combustion device according to any one of the aforementioned embodiments.

[0023] The beneficial effects of the embodiments of the utility model are as follows: the gasified fine slag is introduced into the circulating fluidized combustion furnace for fluidized combustion, the bottom dense phase zone and the middle dilute phase zone of the circulating fluidized combustion furnace adopt an insulated furnace without water-cooled walls, and only the furnace body in the top dilute phase zone is provided with water-cooled walls, which can ensure that the temperature of the gasified fine slag is maintained at a high level during combustion, thereby improving the stability of combustion; the residual carbon of the gasified fine slag after combustion in the circulating fluidized combustion furnace can be further fully burned in the reburner, thereby minimizing the carbon content of the fly ash and improving the combustion efficiency of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the utility model and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 A schematic structural diagram of a combustion device provided in an embodiment of the utility model.

[0026] Icons: 100-combustion device; 110-circulating fluidized bed combustion furnace; 001-fluidized material feed port; 002-gasified fine slag feed port; 003-smoke outlet; 111-bottom dense phase area; 112-middle dilute phase area; 113-top dilute phase area; 114-water cooling wall; 115-returner; 116-return fan; 117-gasified fine slag feeding device; 118-fluidized bed Material feeding device; 120-gas-solid separation device; 130-reburner; 131-reburner fan; 132-reburner air preheater; 141-primary fan; 142-secondary fan; 151-first-stage air preheater; 152-secondary air preheater; 160-superheater; 170-economizer; 181-flue gas purification device; 182-induced draft fan; 183-smoke exhaust device; 190-steam drum. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Generally, the components of the embodiments of the utility model described and shown in the drawings here can be arranged and designed in various different configurations.

[0028] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the present invention to be protected, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0030] In the description of the present utility model, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate the orientation or position relationship based on the orientation or position relationship shown in the accompanying drawings, or the orientation or position relationship in which the utility model product is usually placed when in use, which is only for the convenience of describing the utility model and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present utility model. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0031] In addition, the terms "horizontal", "vertical" and the like do not mean that the components are required to be absolutely horizontal or suspended, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0032] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" 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 or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0033] Please refer to Figure 1 The embodiment of the utility model provides a combustion device 100, including a circulating fluidized combustion furnace 110, a gas-solid separation device 120 and a reburner 130. The gasified fine slag first enters the circulating fluidized combustion furnace 110 for fluidized combustion. After combustion, the hot flue gas containing particulate matter is output at the top and enters the gas-solid separation device 120 for gas-solid separation. Then, the flue gas carries a small amount of solid particles and enters the reburner 130 for further suspended combustion, thereby further burning the residual carbon to achieve the purpose of sufficient combustion.

[0034] The circulating fluidized combustion furnace 110 is provided with a bottom dense phase zone 111, a middle dilute phase zone 112 and a top dilute phase zone 113 from bottom to top, and the circulating fluidized combustion furnace 110 is provided with a water-cooled wall 114 only on the furnace body of the top dilute phase zone 113. The bottom dense phase zone 111 and the middle dilute phase zone 112 are insulated furnaces formed of high-temperature insulation materials, which can greatly alleviate the wear problem of the water-cooled wall. The water-cooled wall is only provided in the top dilute phase zone 113, and the bottom dense phase zone 111 and the middle dilute phase zone 112 adopt an insulated furnace, without water-cooled walls and other heating surfaces. Therefore, it can ensure that the temperature of the gasified fine slag is maintained at a high level during combustion, improve the stability of combustion, and prevent the occurrence of bed flameout.

[0035] It should be noted that conventional circulating fluidized combustion furnaces are mostly equipped with water pipes for heat exchange on the entire furnace wall, which heats the water pipes to generate gas while burning, which can easily cause the bed layer to extinguish for the refined slag with low calorific value. By setting the circulating fluidized combustion furnace 110 as a three-stage structure, only water-cooled walls are set in the top dilute phase zone 113, and adiabatic combustion is performed in the bottom dense phase zone 111 and the middle dilute phase zone 112, the combustion stability is improved.

[0036] Specifically, the "low calorific value gasification fine slag" mentioned in the embodiment of the utility model means that the water content of the gasification fine slag is less than 40wt%, the calorific value is greater than 4200kJ / kg, and the particle size range is 0.01mm-0.3mm. Before entering the circulating fluidized combustion furnace 110, it needs to be pre-dried until the moisture meets the requirements.

[0037] Specifically, the furnace bodies of the bottom dense phase zone 111 and the middle dilute phase zone 112 are formed of high-temperature refractory materials, and the types of high-temperature refractory materials are not limited, such as high-temperature refractory bricks and high-temperature castables. The heights of the bottom dense phase zone, the middle dilute phase zone and the top dilute phase zone are 0.5m-2m, 1m-3m and 2m-10m respectively. The operating temperature of the bottom dense phase zone of the circulating fluidized combustion furnace is 850℃-1000℃, and the operating wind speed is 0.5m / s-3.0m / s; the operating temperature of the middle dilute phase zone is 850℃-1000℃, and the operating wind speed is 0.5m / s-2.0m / s; the operating temperature of the top dilute phase zone is 800℃-950℃, and the operating wind speed is 0.5m / s-1.0m / s, and the fuel residence time is 10s-20s. The fluidized material feeding device 118 is located above the gasification fine slag feeding device 117, and the operating wind speed in the combustion furnace is always lower than 3m / s, so the sufficient combustion time of the gasification fine slag in the circulating fluidized combustion furnace is guaranteed. In addition, the operating wind speed in the circulating fluidized combustion furnace is low, and the middle and lower parts of the insulated furnace are made of refractory materials, which can greatly alleviate the wear problem of the water-cooled wall.

[0038] Furthermore, a fluidized material feed inlet 001 and a gasified fine slag feed inlet 002 are provided in the middle dilute phase zone 112, and a flue gas outlet 003 is provided in the top dilute phase zone 113. The flue gas outlet 003 is connected to the inlet of the gas-solid separation device 120, the gas phase outlet of the gas-solid separation device 120 is connected to the reburner 130, and the solid phase outlet of the gas-solid separation device 120 is connected to the bottom dense phase zone 111 of the circulating fluidized combustion furnace 110. The fluidized material and gasified fine slag enter the middle dilute phase zone 112 from the fluidized material feed port 001 and the gasified fine slag feed port 002 for fluidized combustion respectively. After combustion, the hot flue gas containing particulate matter is output at the top and enters the gas-solid separation device 120 for gas-solid separation. The solid particles obtained by the gas-solid separation return to the bottom dense phase zone 111 of the circulating fluidized combustion furnace 110 for continued combustion; the flue gas obtained by the gas-solid separation carries a small amount of solid particles into the reburner 130 for further suspended combustion, further burning the residual carbon to achieve the purpose of sufficient combustion.

[0039] In some embodiments, a gasification fine slag feeding device 117 and a fluidization material feeding device 118 are provided at the corresponding fluidization material feed port 001 and the gasification fine slag feed port 002, the gasification fine slag feeding device 117 is connected with the gasification fine slag feed port 002, the fluidization material feeding device 118 is connected with the fluidization material feed port 001, and the fluidization material feed port 001 is located above the gasification fine slag feed port 002, that is, the fluidization material feeding device 118 is located above the gasification fine slag feeding device 117. The gasification fine slag enters the middle dilute phase zone 112 from the gasification fine slag feed port 002 through the gasification fine slag feeding device 117, and the fluidized material enters the middle dilute phase zone 112 from the fluidization material feed port 001 through the fluidization material feeding device 118, and the fluidized material is kept fluidized in the bottom dense phase zone 111 by bottom blasting.

[0040] Specifically, the type of fluidized material is not limited, and can be 0-2 mm quartz sand, coal slag, etc. The density of the fluidized material is relatively large and will not enter the rear end. Only under the blast condition, the height of 0.5-2 meters is reached in the bottom dense phase area 111. The fluidized material transfers heat to the gasified fine slag. The ash density generated by the slag heating combustion is relatively small and will enter the rear end gas-solid separation device 120. The working principle of the circulating fluidized combustion furnace 110 and the structure not mentioned can refer to the prior art.

[0041] Specifically, the gas-solid separation device 120 can be a general high-temperature cyclone separator, which is composed of high-temperature refractory materials as a whole, has an operating temperature of 800°C-1000°C, an inlet wind speed of 20m / s-30m / s, and a conical lower portion of the central tube.

[0042] In some embodiments, the solid particles obtained by gas-solid separation are returned to the bottom dense phase zone 111 of the circulating fluidized combustion furnace 110 through a return device 115. The return device 115 has a feed chamber and a return chamber connected to the feed chamber. The feed chamber is connected to the solid phase outlet of the gas-solid separation device 120, and the return chamber is connected to the bottom dense phase zone 111 of the circulating fluidized combustion furnace 110. The feed chamber and the return chamber are both connected to a return fan 116, and the wind speed of the feed chamber and the return chamber is controlled by the return fan 116.

[0043] Specifically, the returner 115 can be a high-temperature returner, which is also made of high-temperature refractory materials, with an operating temperature of 700°C-1000°C, a wind speed of 0.1m / s-0.5m / s in the feed chamber, and a wind speed of 0.5m / s-1m / s in the return chamber. The return blower 116 can be a general Roots blower, which is used to control the wind speed of the feed chamber and the return chamber.

[0044] In some embodiments, preheated gas is blown into the bottom dense phase zone 111 and the middle dilute phase zone 112, and the preheated gas is formed by the primary air fan 141, the secondary air fan 142, the first-stage air preheater 151 and the second-stage air preheater 152. The first-stage air preheater 151 and the second-stage air preheater 152 are both provided with a primary air preheating pipeline and a secondary air preheating pipeline, and the gas output by the primary air fan 141 passes through the primary air preheating pipeline on the first-stage air preheater 151 and the primary air preheating pipeline on the second-stage air preheater 152 in sequence, and then communicates with the bottom dense phase zone 111 of the circulating fluidized combustion furnace 110; similarly, the gas output by the secondary air fan 142 passes through the secondary air preheating pipeline on the first-stage air preheater 151 and the secondary air preheating pipeline on the second-stage air preheater 152 in sequence, and then communicates with the middle dilute phase zone 112 of the circulating fluidized combustion furnace 110. The first-stage air preheater 151 and the second-stage air preheater 152 are used for two-stage preheating, so that the air input into the circulating fluidized bed combustion furnace 110 has a higher initial temperature to meet the process requirements.

[0045] Specifically, the temperature of the primary air input into the bottom dense phase zone 111 is 150° C.-300° C., and the temperature of the secondary air input into the middle dilute phase zone is 200° C.-350° C. The gasified fine slag and the large-particle fluidized material are fully mixed and fluidized under the action of the primary air, and are initially burned in the dense phase zone at the bottom of the circulating fluidized combustion furnace 110, and continue to burn in the middle dilute phase zone with the secondary air.

[0046] Specifically, the reburner 130 is used to further burn the residual carbon after combustion in the circulating fluidized combustion furnace 110, thereby minimizing the carbon content of the fly ash and improving the combustion efficiency of the system.

[0047] In some embodiments, a reburning fan 131 and a reburning air preheater 132 are further provided, the outlet of the reburning fan 131 is connected to the inlet of the reburning air preheater 132, and the outlet of the reburning air preheater 132 is connected to the reburner 130. The air is outputted from the reburning fan 131 to the reburning air preheater 132 for preheating, and the preheated air enters the reburner 130.

[0048] Specifically, the entire reburner is composed of high-temperature refractory materials, the temperature of the reburner air introduced into the reburner is 300℃-400℃, the operating temperature of the reburner is controlled to be 700℃-1000℃, the fuel residence time is 5s-10s, the outlet oxygen content of the reburner is 2%-6%, and the inlet smoke velocity of the reburner is 0.3m / s-1m / s.

[0049] In some embodiments, a superheater 160 and an economizer 170 are also provided, and the flue gas output from the flue gas outlet of the reburner 130 is cooled and heat-exchanged sequentially through the superheater 160, the reburner air preheater 132, the economizer 170, the secondary air preheater 152, and the primary air preheater 151, so as to make full use of the heat and improve the energy utilization rate. The flue gas output from the reburner 130 is used as the heat source of the superheater 160, the reburner air preheater 132, the economizer 170, the secondary air preheater 152, and the primary air preheater 151 in sequence. The superheater 160 has the highest temperature requirement for the heat source, and the order in which the flue gas passes is set according to the different temperature requirements of each component for the heat source.

[0050] Specifically, superheaters and economizers are also commonly used heat transfer equipment, and their structures and working principles are not described in detail here.

[0051] In some embodiments, a drum 190 is provided for heat exchange with the top freeboard zone 113, and an external water supply inlet and an external water supply outlet are provided on the economizer 170. The external water supply outlet is connected to the drum 190, and the bottom outlet of the drum 190 is connected to the bottom inlet of the water-cooled wall 114 on the top freeboard zone 113, and the top outlet of the water-cooled wall 114 is connected to the drum 190. The external water supply is heated by the economizer 170 and then sent to the drum 190. The main function of the drum 190 is to separate steam and water. The saturated water at the lower end of the drum 190 is sent to the lower end inlet of the water-cooled wall 114 by an unheated downcomer. The saturated water absorbs heat and vaporizes in the water-cooled wall 114 arranged at the upper part of the circulating fluidized combustion furnace 110, and the generated steam-water mixture returns to the drum 190 from the upper end.

[0052] Furthermore, the top outlet of the drum 190 is connected to the superheater 160, and the steam outlet of the superheater 160 is connected to the steam turbine. The saturated steam generated by the drum 190 is transported from the upper outlet to the superheater 160 for further superheating, and the steam at the outlet of the superheater 160 is transported to the steam turbine for work.

[0053] In some embodiments, a flue gas purification device 181, an induced draft fan 182 and a smoke exhaust device 183 are further provided, the flue gas outlet on the primary air preheater 151 is connected to the inlet of the flue gas purification device 181, the outlet of the flue gas purification device 181 is connected to the inlet of the induced draft fan 182, and the outlet of the induced draft fan 182 is connected to the smoke exhaust device 183. After the flue gas output from the primary air preheater 151 passes through the flue gas purification device 181 for dust removal, it enters the smoke exhaust device 183 through the induced draft fan 182 for discharge.

[0054] The embodiment of the utility model provides a combustion system, including a combustion device 100, and may also include a coal gasification device. The coal gasification device is used to implement a coal gasification process. The combustion device 100 is used to further burn the gasified fine slag produced by the coal gasification process, so that the gasified fine slag can be reasonably utilized. Specific embodiments

[0056] The selected raw material 1 is the fine slag from the third phase of Weihua gasification, with a particle size of 0.01-0.3mm; the fluidized material is river sand, with a particle size of 0.1-2mm.

[0057] use Figure 1 The combustion device 100 in the 2MWt pilot platform was operated stably for 6 hours, during which sampling and analysis tests were performed. The industrial analysis, elemental analysis and calorific value of the raw material 1 are shown in Table 1. The water content of the raw material is 31.09% and the calorific value is 1669 kcal / kg.

[0058] Table 1 Analytical data of raw material 1

[0059]

[0060] The heights of the bottom dense phase zone 111, the middle dilute phase zone 112 and the top dilute phase zone 113 are 50 cm, 200 cm and 500 cm respectively.

[0061] During the stable operation of the system, the feed rate of raw material 1 is 254.4 kg / h.

[0062] During the stable operation of the system, the operating parameters of the main parts are as follows:

[0063] The temperature of the dense phase zone 111 at the bottom of the circulating fluidized combustion furnace ranges from 939-976°C, with an average of 955°C and an operating wind speed of 1m / s; the temperature of the dilute phase zone in the middle of the circulating fluidized combustion furnace ranges from 910-958°C, with an average of 936°C and an operating wind speed of 0.5m / s; the temperature of the dilute phase zone 113 at the top of the circulating fluidized combustion furnace ranges from 853-892°C, with an average of 867°C and an operating wind speed of 0.5m / s. The primary air temperature is 150°C and the secondary air temperature is 200°C.

[0064] The operating temperature of the high temperature cyclone separator is 950°C and the inlet wind speed is 25m / s.

[0065] The operating temperature of the high temperature return device 115 is 900° C., the wind speed in the feed chamber is 0.2 m / s, and the wind speed in the return chamber is 0.5 m / s.

[0066] The reburner temperature range is 702-768℃, with an average value of 735℃; the inlet smoke velocity is 0.5m / s, the reburner air temperature is 300℃, the fuel residence time is 10s, and the reburner outlet oxygen concentration range is 2.2%-4.3%, with an average value of 3.1%.

[0067] According to DL / T 567.6-2016 "Test Methods for Fuels in Thermal Power Plants (Part 6: Determination of Combustible Matter in Fly Ash and Slag)", the fly ash and bottom ash sampled during the stable operation of the system were tested for combustible content. The test results showed that the carbon content of the fly ash was 3.03% and the carbon content of the bottom ash was 0.20%.

[0068] According to calculations in accordance with GB / T 10184-2015 "Power Plant Boiler Performance Test Procedure", the combustion efficiency of the raw material 1 in this embodiment is 93%.

[0069] During the stable operation of the system, when no denitrification device is working, the NO x The average value of the original emission concentration is 16.5ppm, and the average oxygen content in the flue gas is 8.47%, which is converted to NO under the standard oxygen content of 6%. x The emission concentration is 40.6mg / Nm 3 , better than NO x National ultra-low emission standard concentration 50mg / Nm 3 limit.

[0070] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may be subject to various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A combustion device, characterized in that: The circulating fluidized combustion furnace comprises a circulating fluidized combustion furnace, a gas-solid separation device and a reburner, wherein the circulating fluidized combustion furnace is provided with a bottom dense phase zone, a middle dilute phase zone and a top dilute phase zone from bottom to top, and the circulating fluidized combustion furnace is provided with a water-cooled wall only on the furnace body of the top dilute phase zone; A fluidized material feed port and a gasified fine slag feed port are provided in the middle dilute phase zone, and a flue gas outlet is provided in the top dilute phase zone. The flue gas outlet is connected to the inlet of the gas-solid separation device, the gas phase outlet of the gas-solid separation device is connected to the reburner, and the solid phase outlet of the gas-solid separation device is connected to the bottom dense phase zone of the circulating fluidized combustion furnace.

2. The combustion device according to claim 1, characterized in that: It also includes a primary air fan, a secondary air fan, a first-level air preheater and a second-level air preheater. The first-level air preheater and the second-level air preheater are both provided with a primary air preheating pipe and a secondary air preheating pipe. The gas output by the primary air fan passes through the primary air preheating pipe on the first-level air preheater and the primary air preheating pipe on the second-level air preheater in sequence, and then is connected to the bottom dense phase area of ​​the circulating fluidized combustion furnace. The gas output by the secondary air fan passes through the secondary air preheating pipe on the first-level air preheater and the secondary air preheating pipe on the second-level air preheater in sequence, and then is connected to the middle dilute phase area of ​​the circulating fluidized combustion furnace.

3. The combustion device according to claim 2, characterized in that: It also includes a reburning fan and a reburning air preheater, wherein the outlet of the reburning fan is connected to the inlet of the reburning air preheater, and the outlet of the reburning air preheater is connected to the reburner.

4. The combustion device according to claim 3, characterized in that: It also includes a superheater and an economizer. The flue gas output from the flue gas outlet of the reburner is cooled and heat-exchanged through the superheater, the reburning air preheater, the economizer, the secondary air preheater and the primary air preheater in sequence.

5. The combustion device according to claim 4, characterized in that: It also includes a flue gas purification device, an induced draft fan and a smoke exhaust device. The flue gas outlet on the first-stage air preheater is connected to the inlet of the flue gas purification device, the outlet of the flue gas purification device is connected to the inlet of the induced draft fan, and the outlet of the induced draft fan is connected to the smoke exhaust device.

6. The combustion device according to claim 4, characterized in that: It also includes a steam drum, and the economizer is provided with an external water supply inlet and an external water supply outlet, the external water supply outlet is connected to the steam drum, the bottom outlet of the steam drum is connected to the bottom inlet of the water-cooled wall on the top freeboard zone, and the top outlet of the water-cooled wall is connected to the steam drum.

7. The combustion device according to claim 6, characterized in that: The top outlet of the steam drum is communicated with the superheater, and the steam outlet of the superheater is communicated with the steam turbine.

8. The combustion device according to claim 1, characterized in that: It also includes a return device and a return blower, wherein the return device has a feed chamber and a return chamber connected to the feed chamber, the feed chamber is connected to the solid phase outlet of the gas-solid separation device, the return chamber is connected to the bottom dense phase area of ​​the circulating fluidized combustion furnace, and the feed chamber and the return chamber are both connected to the return blower.

9. The combustion device according to claim 1, characterized in that: The furnace bodies of the bottom dense phase zone and the middle rarefied phase zone are formed of high temperature refractory materials; It also includes a gasification fine slag feeding device and a fluidized material feeding device, the gasification fine slag feeding device is connected to the gasification fine slag feed port, the fluidized material feeding device is connected to the fluidized material feed port, and the fluidized material feed port is located above the gasification fine slag feed port.

10. A combustion system, characterized in that: A combustion device comprising the combustion device according to any one of claims 1 to 9.

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