CN114317035B - Gasification cold slag device and gasification cold slag method - Google Patents

Abstract

The invention provides a cold sediment device of gasification and cold sediment method, wherein above-mentioned cold sediment device of gasification includes: a gasification unit for carrying out a gasification reaction of the fuel and the gasifying agent in the gasification unit and producing slag in a first temperature range; and the slag cooling unit is provided with a fluidized cooling medium inlet, wherein the fluidized cooling medium inlet is used for introducing a fluidized cooling medium with a preset temperature and a preset wind speed, so that the slag in the first temperature range can form first-particle-size slag in the second temperature range and second-particle-size slag in the second temperature range under the action of fluidized transport and impact physical cooling of the fluidized cooling medium.

Description

Gasification cold slag device and gasification cold slag method

Technical Field

The disclosure relates to the technical field of hydrocarbon fuel energy chemical industry, in particular to a gasification cold slag device and a gasification cold slag method.

Background

Coal gasification is one of core technologies of clean and efficient utilization technologies of coal, and is the basis for developing coal-based chemical products, coal-based clean fuels, industrial gas, poly-generation systems and other coal chemical process industries. The fluidized bed gasification furnace adopts pulverized coal as a raw material, a gasification agent and the pulverized coal carry out gasification reaction in a fluidized form, and solid-state slag discharge is adopted. The fluidized bed gasification furnace has the advantages of strong coal adaptability, no tar in coal gas, high gasification strength and the like, and is widely applied to the reformation of coal-to-industrial gas and small and medium-sized synthetic ammonia gas sources.

At present, in a cold slag system of a fluidized bed gasification furnace, due to unreasonable cold slag structural design, the technical problems of low slag cooling efficiency, high carbon content of bottom slag and the like are caused.

Disclosure of Invention

In view of the above, the present disclosure provides a slag cooling device and a slag cooling method for gasification, so as to at least partially solve the above-mentioned technical problems.

In order to achieve the above objects, in one aspect, the present disclosure provides a gasification cold slag device, including:

a gasification unit for carrying out a gasification reaction of the fuel and the gasifying agent in the gasification unit and producing slag in a first temperature range;

and the slag cooling unit is provided with a fluidized cooling medium inlet, wherein the fluidized cooling medium inlet is used for introducing a fluidized cooling medium with a preset temperature and a preset wind speed, so that the slag in the first temperature range forms slag with a first particle size in the second temperature range and slag with a second particle size in the second temperature range under the action of fluidized transportation and impact physical cooling of the fluidized cooling medium.

According to the embodiment of the present disclosure, the cold slag unit is further provided with:

a discharge opening for discharging the slag of the first particle size in the second temperature range;

and the powder returning port is used for returning the second-particle-size slag in the second temperature range to the gasification unit so that the second-particle-size slag in the second temperature range can be subjected to gasification reaction in the gasification unit.

According to an embodiment of the present disclosure, a gasification unit is provided with:

the secondary air port is communicated with the powder return port, is arranged in a transition area of a dilute phase area and a dense phase area of the gasification unit and is used for introducing second-particle-size slag in a second temperature range into the transition area of the gasification unit, and the secondary air port is also used for introducing a secondary air gasifying agent;

and the primary air port is used for introducing a primary air gasifying agent.

According to an embodiment of the disclosure, the fluidizing cooling medium comprises at least one of: saturated water vapor, carbon dioxide;

the cold slag unit is also used for slag and fluidized cooling medium in a first temperature range, and a gasification reaction is carried out in the cold slag unit, so that the slag in the first temperature range is subjected to chemical cooling in an endothermic manner through the gasification reaction.

According to this disclosed embodiment, cold sediment device of gasification still includes:

and the slag conveying device is used for conveying the slag in the first temperature range into the cold slag unit, wherein the slag conveying device is a device with adjustable conveying capacity.

According to the embodiment of the disclosure, a descending pipe is arranged between the slag conveying device and the gasification unit and used for conveying the slag in the first temperature range into the slag conveying device, wherein a loosening air port is formed in the descending pipe and used for introducing loosening air into the descending pipe to loosen the slag and prevent the slag from carrying a gasification agent and entering the descending pipe to react to cause slagging.

According to the embodiment of the disclosure, the cold slag unit is further provided with a supplementary fluidized cooling medium inlet for introducing supplementary fluidized cooling medium into the cold slag unit, wherein the supplementary fluidized cooling medium is arranged on the side wall of the cold slag unit, and the fluidized cooling medium inlet is arranged at the bottom of the cold slag unit.

According to the embodiment of the disclosure, the cold slag unit adopts a spout fluidization device, wherein the spout fluidization device is provided with a spout and a fluidization port, and the spout and the fluidization port are used for introducing a fluidization cooling medium; a central guide cylinder is also arranged in the spouted fluidizing device, and a heat exchange tube is arranged in the area between the central guide cylinder and the inner wall of the spouted fluidizing device.

On the other hand, the disclosure also provides a method for gasifying cold slag by using the cold slag gasifying device, which comprises the following steps:

conveying the slag in the first temperature range from the gasification unit into a cold slag unit through a slag conveying device with adjustable conveying capacity;

feeding a fluidizing cooling medium with a preset temperature and a preset wind speed into the slag cooling unit so that the slag in the first temperature range forms slag with a first particle size in the second temperature range and slag with a second particle size in the second temperature range under the action of fluidizing transportation and impact physical cooling of the fluidizing cooling medium;

returning the second-size slag in the second temperature range to the gasification unit so that the second-size slag in the second temperature range undergoes a gasification reaction in the gasification unit.

According to an embodiment of the present disclosure, the fluidizing cooling medium comprises at least one of: saturated water vapor and carbon dioxide.

According to an embodiment of the disclosure, the method of gasifying cold slag further comprises: the slag and the fluidized cooling medium in the first temperature range are subjected to a gasification reaction in the cold slag unit, so that the slag in the first temperature range is chemically cooled in an endothermic manner by the gasification reaction.

Based on the technical scheme, compared with the prior art, the method has at least one or one part of the following beneficial effects:

according to this disclosed embodiment, the high temperature slag that gasification reaction produced in the gasification unit is in cold sediment unit, through the impact physics cooling effect of fluidization cooling medium, makes the in-process that high temperature slag upwards carries out fluidization transportation, constantly is cooled off, because of fluidization cooling medium has certain wind speed, and the impingement cooling effect is superior to conventional natural convection heat transfer effect, and the cooling effect is better. Meanwhile, in the process of upward conveying of the slag, under the action of the self large-particle and small-particle self-weight difference, automatic separation of materials is realized, low-temperature coarse-particle slag and low-temperature fine-particle slag are formed, and the follow-up process is convenient for returning the fine-particle slag with higher carbon content to the gasification unit to continuously participate in gasification reaction. In conclusion, by the method of the embodiment of the disclosure, the high-temperature slag is cooled by itself and simultaneously realizes material separation under the action of the fluidized cooling medium, so that a material separation device is omitted, and the cooling effect is improved.

Drawings

FIG. 1 schematically shows a structural diagram of a gasification cold slag device according to an embodiment of the disclosure;

FIG. 2 is a schematic structural diagram of a gasification cold slag device according to another embodiment of the disclosure;

FIG. 3 schematically shows a structural diagram of a cold slag unit according to an embodiment of the disclosure;

FIG. 4 is a schematic structural diagram of a cold slag unit according to another embodiment of the disclosure;

FIG. 5 schematically illustrates a cold slag unit structure according to yet another embodiment of the disclosure;

fig. 6 schematically shows a flow chart of a method for gasifying cold slag by using the gasification cold slag device in the embodiment of the disclosure.

Description of reference numerals:

1-a gasification unit; 11-secondary air port; 12-primary air port; 13-a vent; 14-a feed port; 15-a feed port; 16-a slag discharge port; 551-a feed zone; 552-a cooling zone; 553-powder return area; 2-a gas-solid separation unit; 3-a material returning unit; 4-a slag transport device; 41-a downcomer; 42-loosening the tuyere; 5-a slag cooling unit; 51-a fluidized cooling medium inlet; 52-a discharge outlet; 53-powder return port; 54-a slag inlet; 55-make-up fluidizing cooling medium inlet; 56-nozzle; 57-a fluidization port; 58-central draft tube.

Detailed Description

For the purpose of promoting a better understanding of the objects, aspects and advantages of the present disclosure, reference is made to the following detailed description taken in conjunction with the accompanying drawings.

Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. It should be understood that the description is illustrative only and is not intended to limit the scope of the present disclosure. In the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the embodiments of the disclosure. It may be evident, however, that one or more embodiments may be practiced without these specific details. Moreover, in the following description, descriptions of well-known structures and techniques are omitted so as to not unnecessarily obscure the concepts of the present disclosure.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. The terms "comprises," "comprising," and the like, as used herein, specify the presence of stated features, steps, operations, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, or components.

All terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art unless otherwise defined. It is noted that the terms used herein should be interpreted as having a meaning that is consistent with the context of this specification and should not be interpreted in an idealized or overly formal sense.

Where a convention analogous to "at least one of A, B and C, etc." is used, in general such a construction should be interpreted in the sense one having ordinary skill in the art would understand the convention (e.g., "a system having at least one of A, B and C" would include but not be limited to systems that have a alone, B alone, C alone, a and B, a and C, B and C, and/or A, B, C, etc.). Where a convention analogous to "A, B or at least one of C, etc." is used, in general such a construction should be interpreted in the sense one having ordinary skill in the art would understand the convention (e.g., "a system having at least one of A, B or C" would include but not be limited to systems that have a alone, B alone, C alone, a and B, a and C, B and C, and/or A, B, C, etc.).

At present, the slag cooling mode of the fluidized bed gasification furnace generally adopts an indirect heat exchange mode to cool bottom slag, for example, a mechanical roller slag cooler is adopted, or a moving bed serpentine heat exchange tube is adopted. The mechanical roller slag cooler is adopted, although the heat transfer between solid particles and the heat exchange tube can be enhanced through mechanical rotation, the heat transfer coefficient is still low, the problem of leakage often occurs in the sealing of a rotating part, and particularly on a pressurized fluidized bed, the problem of leakage of the sealing surface of the rotating part is more serious. The slag cooler of the snakelike heat exchange tube form of moving bed, because heat exchange tube and sediment, the coefficient of heat transfer between sediment and the sediment is little, appears the bias current easily moreover, leads to the slag cooler volume very huge, has increased fluidized bed gasifier device's construction cost, and slag cooler inner structure is very complicated moreover, is unfavorable for the later stage and overhauls.

In addition, the bottom of the traditional fluidized bed gasification furnace is seriously back-mixed, and a large amount of fine materials with higher carbon content returned by the material returning device are discharged out of the system along with the slag without having time to react, so that the carbon content of the bottom slag is higher.

Therefore, the disclosure provides a gasification cold slag device and a gasification cold slag method.

The following schematically illustrates a gasification cold slag apparatus of the present disclosure. It should be noted that the illustrated embodiments are only specific examples of the disclosure, and should not limit the scope of the disclosure.

Fig. 1 schematically shows a structural schematic diagram of a gasification cold slag device according to an embodiment of the disclosure.

As shown in fig. 1, the gasification cold slag device comprises: a gasification unit 1 and a cold slag unit 5.

The gasification unit 1 can be used for the gasification reaction of the fuel and the gasifying agent in the gasification unit 1 and generating slag in a first temperature range (i.e. high-temperature slag before cooling, the first temperature range is about 900-1000 ℃); wherein, the bottom of the gasification unit 1 is provided with an air distribution section which can be a cone structure with a small lower part and a big upper part, and the cone angle alpha can be 10-40 degrees.

The slag cooling unit 5 is provided with a fluidized cooling medium inlet 51 arranged at the bottom of the slag cooling unit 5, wherein the fluidized cooling medium inlet 51 is used for introducing a fluidized cooling medium with a preset temperature and a preset wind speed, so that the slag in the first temperature range forms first-particle-size slag in the second temperature range and second-particle-size slag in the second temperature range under the action of fluidized transport and impact physical cooling of the fluidized cooling medium. Wherein the cooled low temperature slag is in a second temperature range, which is approximately 200-450 ℃. The first size slag is a larger coarse grain slag. The second-size slag is a fine-grained slag having a relatively high carbon content compared to coarse grains. In addition, the fluidized cooling medium with the preset temperature needs to be introduced at the preset wind speed, and the fluidized cooling medium with the preset temperature can be a normal-temperature cooling medium (the temperature ranges from 0 ℃ to 200 ℃), such as saturated steam with the temperature of 115 ℃, or carbon dioxide, or nitrogen, and the like. The fluidized cooling medium is fed at a predetermined wind speed to achieve a predetermined cooling effect and achieve material separation. The predetermined wind speed may be between 4m/s and 8m/s, which is higher than the apparent wind speed inside the gasification unit 1.

According to the embodiment of the disclosure, high-temperature slag generated by gasification reaction in the gasification unit is continuously cooled in the process of upward fluidized transportation of the high-temperature slag in the slag cooling unit under the impact physical cooling effect of the fluidized cooling medium, and the impact cooling effect is better than the conventional natural convection heat exchange effect because the fluidized cooling medium has a certain wind speed, so that the cooling effect is better. Meanwhile, in the process of upward conveying of the slag, under the action of the self large-particle and small-particle self-weight difference, automatic separation of materials is realized, low-temperature coarse-particle slag and low-temperature fine-particle slag are formed, and the follow-up process is convenient for returning the fine-particle slag with higher carbon content to the gasification unit to continuously participate in gasification reaction. In conclusion, by the method of the embodiment of the disclosure, the high-temperature slag is cooled by itself and simultaneously realizes material separation under the action of the fluidized cooling medium, so that a material separation device is omitted, and the cooling effect is improved.

According to embodiments of the present disclosure, the fluidizing cooling medium may include at least one of: the saturated water vapor and the carbon dioxide may be, for example, saturated water vapor or carbon dioxide, or a mixed gas of saturated water vapor and carbon dioxide. The temperature of the carbon dioxide may range from 0 to 50 ℃.

According to an embodiment of the present disclosure, the above kind of gas may be used as a gasifying agent, and by limiting the kind of the fluidized cooling medium to the above kind, the slag and the fluidized cooling medium in the first temperature range, a gasification reaction may also occur in the cold slag unit 5 so as to chemically cool the slag in the first temperature range through a gasification reaction endothermically. Therefore, the cooling of the high-temperature slag can be further enhanced on the basis of the physical cooling of the high-temperature slag.

According to embodiments of the present disclosure, the cold slag unit 5 may include a feed section 551, a cooling section 552, and a return powder section 553. The feeding area 551 of the cold slag unit 5 can also be provided with a slag inlet 54, the cooling area 552 can be provided with a discharge opening 52, and the powder returning area 553 can be provided with a powder returning opening 53.

Wherein the discharge opening 52 is capable of discharging the slag of the first grain size in the second temperature range; the dust return port 53 may return the second-size slag in the second temperature range to the gasification unit 1 so that the second-size slag in the second temperature range undergoes a gasification reaction in the gasification unit 1. The cold slag unit 5 may be a differential fluidized bed, and the apparent wind speed at the section where the slag inlet 54 of the cold slag unit 5 is located may be 4m/s to 8m/s, which is higher than the apparent wind speed in the gasification unit 1. As the fluidized cooling medium enters from the fluidized cooling medium inlet 51 and is fluidized with the slag in the first temperature range entering from the slag inlet 54 upwards, the apparent wind speed of the cold slag unit 5 can be reduced, the apparent wind speed of the cross section where the discharge opening 52 is positioned can be reduced to 2 m/s-4 m/s, and the apparent wind speed of the cross section from the discharge opening 52 upwards to the powder returning area of the cold slag unit 5 can be reduced to 0.5 m/s-1 m/s. After entering the cold slag unit 5, the fluidized cooling medium is fluidized and transported upwards in the cold slag unit 5, and is influenced by the difference of apparent wind speeds of cross sections at different heights and under the action of impact physical cooling, so that the separation of the first-particle-size slag (large particle size) in the second temperature range and the second-particle-size slag (high carbon content and small particle size) in the second temperature range is completed while the cold slag unit 5 cools the hot slag from the gasification unit 1. The average residence time of the slag in the cold slag unit 5 may be, for example, 0.15s to 8s, and the temperature of the slag leaving the cold slag device may be < 450 ℃.

The gasification unit 1 may also be provided with a secondary tuyere 11, a primary tuyere 12.

The secondary tuyere 11 is communicated with the powder return port 53, is arranged in a transition area of a dilute phase area and a dense phase area of the gasification unit 1, and can be used for introducing second-particle-size slag in a second temperature range into the transition area of the gasification unit 1, and the secondary tuyere 11 can also be used for introducing a secondary air gasification agent. Specifically, a plurality of nozzles are uniformly distributed on the secondary tuyere 11, one of the nozzles is communicated with the powder return port 53 to form a combined nozzle, and the secondary-particle-size slag and the secondary air gasifying agent are introduced into a transition area of the gasification unit through the combined nozzle. For example, the secondary tuyere 11 may be provided as a multi-channel nozzle in which the central channel is a small-particle-size slag channel and the gas-solid flow rate of the small-particle-size slag channel may be 10m/s to 30m/s. The secondary air gasifying agent can be any mixed gas of air, oxygen, water vapor and carbon dioxide, wherein the oxygen-enriched concentration can be 21-80%, and the flow speed of the secondary air gasifying agent entering the nozzle can be 60-150 m/s.

It should be noted that, in the dilute phase zone of the gasification unit 1, the slag concentration is low, and the dilute phase zone is located in the upper part of the gasification unit 1; the dense phase zone of the gasification unit 1, which is high in slag concentration, is located in the lower part of the gasification unit 1.

The secondary tuyere 11 is communicated with the powder returning port 53 and is arranged in a transition area of a dilute phase area and a dense phase area of the gasification unit 1, so that the slag with the second particle size and the secondary air gasifying agent within a second temperature range discharged from the powder returning port 53 by the cold slag unit 5 smoothly enter the gasification unit 1 to generate gasification reaction. Because the second-particle-size slag flowing out of the powder returning opening 53 in the second temperature range has high carbon content and small particle size, if the second-particle-size slag enters the dense-phase region of the gasification unit 1, the second-particle-size slag in the second temperature range is influenced by slag resistance in the dense-phase region, so that the second-particle-size slag in the second temperature range is blocked from entering the gasification unit 1, and the slag returns to the cold slag unit 5, and the conditions of unstable operation of the nozzle, slag bonding and the like also occur; since the secondary tuyere 11 and the return dust port 53 need to be connected to each other and disposed in a transition region between the dilute phase region and the dense phase region of the gasification unit 1, the secondary tuyere needs to be affected by the temperature required for the gasification reaction when entering the dilute phase region of the gasification unit 1.

The primary air port 12 may be disposed at the bottom end of the air distribution section at the bottom of the gasification unit 1 for introducing a primary air gasification agent. For example, the primary air gasifying agent can be a mixed gas of water vapor and one of air, oxygen-enriched air and pure oxygen. The gasification reaction can be air gasification reaction, oxygen-enriched gasification reaction or pure oxygen gasification reaction. The primary air port can be used for introducing a primary air gasifying agent so as to generate a gasification reaction with the fuel and generate the slag in a first temperature range.

According to another embodiment of the present disclosure, the gasification unit 1 may also be provided with a vent 13, a feed port 14, a return slag port 15, and a slag discharge port 16. Wherein, the ventilation opening 13 can be arranged on the other side of the section of the secondary air opening 11, and the function of the secondary air opening 11 for introducing the secondary air gasifying agent is the same. The feed port 14 may be located in the freeboard area of the gasification unit 1 and may be used to receive fuel from the reaction furnace. The slag return port 15 may be disposed below the vent 13, and may be configured to return slag, which is generated after the gasification reaction of the gasification unit 1 and after gas-solid separation, within the first temperature range to the gasification unit 1. The slag discharge port 16 may be disposed at a lower side of the air distribution section of the gasification unit 1 and lower than the cross section of the slag return port 15, and may be configured to discharge slag in the first temperature range returned by the slag return port 15 out of the gasification unit 1.

According to the embodiment of the disclosure, the secondary air gasifying agent is introduced through the vent and the secondary air vent is arranged to assist the vent, because the carbon content of the second-particle-size slag flowing out of the powder return port in the second temperature range is high, the particle size is small, the flowing speed is high, enough secondary air gasifying agent is supplemented, the gasification reaction is fully reacted, and the phenomenon that the secondary air gasifying agent is discharged out of the gasification unit again after the secondary air gasifying agent is not reacted completely or even unreacted completely is avoided.

According to still another embodiment of the present disclosure, the cold slag gasification device may further include a slag transport device 4 disposed between the gasification unit 1 and the cold slag unit 5, and configured to transport slag in the first temperature range into the cold slag unit 5, where the slag transport device is a device with an adjustable transport capacity. The slag conveying device 4 can be a mechanical conveying device or a non-mechanical jet flow conveying device, for example, the mechanical conveying device can adjust and control the slag conveying amount by adjusting the rotation frequency; the non-mechanical jet flow conveying device can realize the regulation and control of the slag conveying capacity by changing the wind speed of jet flow wind, and the wind speed range of the jet flow wind is 15-60 m/s.

According to the embodiment of the disclosure, by arranging the slag conveying device with adjustable conveying capacity, the cold slag unit can stably operate by controlling the amount of the slag entering the cold slag unit.

According to the embodiment of the disclosure, a downcomer 41 may be further provided between the slag transport device 4 and the gasification unit 1, one end of the downcomer 41 may be communicated with the slag transport device 4, and the other end may be communicated with the slag discharge port 16 of the gasification unit 1, for feeding slag in the first temperature range into the slag transport device 4. The descending pipe 41 may further be provided with a loosening wind port 42 for introducing loosening wind into the descending pipe, wherein the loosening wind plays a role in loosening the downward moving slag and preventing the slag from entering the descending pipe along with gasifying agents such as air or oxygen and the like to react and form slag. For example, 1 or more layers of loosening tuyere 42 may be provided along the downcomer 41, and the loosening gas uniformly enters the downcomer 41 through the loosening tuyere 42. The loosening wind can be nitrogen, water vapor, carbon dioxide or three groups of mixed gas mixed at will. In order to avoid slag in the downcomer 41 from back-mixing with slag in the gasification unit 1 due to the slag in the first temperature range flowing in the downcomer 41, the loosening wind acts as a draft wind, and the superficial fluidization velocity of the gas in the downcomer 41 may be 0.01m/s to 0.25m/s. Wherein, in order to avoid the slag in the first temperature range from entraining air or oxygen into the downcomer 41, the height of the material seal of the downcomer 41 can be 0.5 m-3 m, the downward movement speed of the slag can be less than 0.5m/s, or the downward movement speed of the slag can be less than 0.1m/s.

Fig. 2 schematically shows a structural schematic diagram of a gasification cold slag device according to another embodiment of the disclosure.

As shown in fig. 2, the embodiment of the present disclosure is substantially the same as the gasification cold slag device in the embodiment shown in fig. 1, except that: the gasification cold slag device provided by the embodiment of the disclosure further comprises a gas-solid separation unit 2 and a material returning unit 3. One end of the gas-solid separation unit 2 is connected with a gas and circulating material outlet at the top of the gasification unit 1 and is used for separating gas generated by gasification reaction from circulating material. The inlet of the material returning unit 3 is communicated with the solid material outlet of the gas-solid separation unit 2, the outlet of the material returning unit 3 is communicated with the material returning port 15 in the gasification unit 1, and the material returning unit is used for returning the solid materials collected by the gas-solid separation unit 2 to the gasification unit to continue gasification reaction.

Fig. 3 schematically shows a structural diagram of a cold slag unit according to an embodiment of the disclosure.

As shown in fig. 3, this embodiment of the present disclosure is substantially the same as the cold slag unit structure of the embodiment shown in fig. 1, except that: the cold slag unit 5 provided by the embodiment of the present disclosure further includes a supplementary fluidized cooling medium inlet 55 for introducing a supplementary fluidized cooling medium into the cold slag unit 5, wherein the supplementary fluidized cooling medium inlet 55 is disposed on a side wall of the cold slag unit 5. For example, 1 to 3 additional layers of supplemental fluidized cooling medium inlets 55 may be additionally arranged in the axial direction of the cold slag unit 5, the supplemental fluidized cooling medium inlets 55 may be disposed at an angle to the furnace wall of the cold slag unit 5, and the supplemental fluidized cooling medium is introduced into the cold slag unit 5 in an obliquely upward feeding manner.

According to the embodiment of the disclosure, the supplementary fluidized cooling medium inlet is arranged, and the fluidized cooling medium is introduced in an obliquely upward feeding mode, so that upward fluidization of the slag in the first temperature range can be carried, heat exchange between the fluidized cooling medium and the slag in the first temperature range in the cold slag unit is enhanced, and the cooling effect of the cold slag unit on the slag in the first temperature range from the gasification unit is enhanced.

Fig. 4 schematically shows a structural diagram of a cold slag unit according to another embodiment of the disclosure.

As shown in fig. 4, the structure of the cold slag unit in this embodiment is substantially the same as that of the embodiment shown in fig. 1, except that: the cold slag unit 5 adopts a spouted fluidizing device, the fluidizing mode of the cooling medium is a spouted fluidizing mode, wherein the spouted fluidizing device is provided with a plurality of nozzles 56 and fluidizing ports 57, the nozzles 56 can be arranged on the bottom wall surface of the cold slag unit 5 respectively, and the bottom wall surface can be arranged into a cone structure with a small lower part and a large upper part. The velocity of the fluidizing cooling medium introduced into the nozzles 56 may be, for example, 20 to 50m/s. The fluidizing port 57 may be provided at the lower small part of the cone structure for feeding a fluidizing cooling medium. The air velocity of the air distribution plate orifice of the fluidizing port 57 may be, for example, 0.1 to 0.5m/s.

According to the embodiment of the disclosure, because of the wind speed of the middle fluidizing port of the cold slag unit 5 is high, the slag charge at the fluidizing port can be well fluidized, but the slag charge is easily piled up at the two sides of the lower inlet of the cold slag unit, and through the arrangement of the spout fluidizing device, the fluidizing and cooling medium introduced from the spout can carry the slag charge piled up at the two sides of the inlet of the cold slag unit 5 to be converged at the middle fluidizing port, so that the slag charge is fully fluidized by the central jet flow, the internal circulation of the slag in the first temperature range is enlarged, the heat exchange is enhanced, and the cooling effect is better.

Fig. 5 schematically shows a structural diagram of a cold slag unit according to still another embodiment of the disclosure.

As shown in fig. 5, the embodiment of the present disclosure has substantially the same structure as the cold slag unit of the embodiment shown in fig. 4, except that: in the cold slag unit 5 provided by the embodiment of the present disclosure, a central guide cylinder 58 is further provided in the spout-fluidizing device, and a heat exchange tube is arranged in a region between the central guide cylinder 58 and an inner wall of the spout-fluidizing device. The central guide cylinder 58 has a lower edge lower than the slag inlet 54 of the cold slag unit 5 and an upper edge flush with the lower edge of the discharge opening 52, so that it is possible to prevent the first-size slag in the second temperature range from being unable to be separated from the second-size slag in the second temperature range and discharged through the discharge opening 52. The inner surface of the central guide shell 58 may have a wind velocity of 4m/s to 8m/s, for example.

According to the embodiment of the disclosure, the central flow can be strengthened by arranging the central guide cylinder, the ordered circulation of the air flow and the slag with the first particle size in the slag cooling unit is organized, the heat exchange is strengthened, and the cooling effect is enhanced. The heat exchange tubes are arranged in the area between the central guide cylinder and the inner wall of the spouted fluidized device, so that the central guide cylinder can be supported, heat exchange can be assisted, and the slag cooling effect is improved.

The disclosure also provides a method for gasifying cold slag by using the device shown in the figures 1-5.

Fig. 6 schematically shows a flow chart of a method for gasifying cold slag by using the gasification cold slag device in the embodiment of the disclosure.

The method for gasifying cold slag according to the embodiment of the present disclosure will be described below with reference to fig. 1, 2, and 6, and as shown in fig. 4, 5, and 6, the method includes operations S601 to S603.

In operation S601, slag in the first temperature range from the gasification unit 1 is fed to the cold slag unit 5.

In operation S601, after the fuel and the gasifying agent are subjected to the gasification reaction in the gasification unit 1, the slag in the first temperature range, which is generated after the gas-solid separation through the slag return port 15, may be returned to the gasification unit 1 and may be fed to the cold slag unit 5 through the slag discharge port 16. Slag in a first temperature range discharged from the slag discharge port 16 can be conveyed into the cold slag unit 5 through the slag conveying device 4; wherein, the slag conveying device 4 is a device with adjustable conveying capacity. The slag conveying device 4 can be a mechanical conveying device or a non-mechanical jet flow conveying device, for example, the mechanical conveying device can realize the regulation and control of slag conveying capacity by regulating the rotation frequency; the non-mechanical jet flow conveying device can realize the regulation and control of the slag conveying capacity by changing the wind speed of jet flow wind, and the wind speed range of the jet flow wind can be 15 m/s-60 m/s, for example.

According to the embodiment of the disclosure, by arranging the slag conveying device with adjustable conveying capacity, the cold slag unit can stably operate by controlling the amount of the slag entering the cold slag unit.

In operation S602, a fluidized cooling medium of a predetermined temperature and a predetermined wind speed is supplied to the slag cooling unit 5, so that the slag in the first temperature range forms slag of a first particle size in the second temperature range and slag of a second particle size in the second temperature range under the fluidized transport and impact physical cooling effects of the fluidized cooling medium.

In the above operation S602, the cold slag unit 5 may discharge the first grain size slag in the second temperature range through the discharge opening 52. The cold slag unit 5 may also feed slag in the first temperature range into the cold slag unit 5 through the slag inlet 54. For example, the cold slag unit 5 is a differential fluidized bed, and the apparent wind speed at the section where the slag inlet 54 of the cold slag unit 5 is located may be 4m/s to 8m/s, which is higher than the apparent wind speed in the gasification unit 1. Since the fluidized cooling medium is fluidized upward with the slag in the first temperature range entering from the slag inlet 54 after entering from the fluidized cooling medium inlet 51, the apparent wind speed of the cold slag unit 5 can be reduced, the apparent wind speed at the cross section where the discharge opening 52 is located can be reduced to 2m/s to 4m/s, and the apparent wind speed at the cross section from the discharge opening 52 to the upper dilute phase zone of the cold slag unit 5 can be reduced to 0.5m/s to 1m/s. After entering the cold slag unit 5, the fluidized cooling medium is fluidized and conveyed upwards in the cold slag unit 5, and is influenced by the difference of apparent wind speeds of cross sections at different heights and under the action of impact physical cooling, so that the separation of the first-particle-size slag (large particle size) in the second temperature range and the second-particle-size slag (high carbon content and small particle size) in the second temperature range is completed while the cold slag unit 5 cools the hot slag from the gasification unit 1. The average residence time of the slag in the slag cooling unit 5 can be 0.15-8 s, and the temperature of the slag leaving the slag cooling device can be lower than 450 ℃.

In operation S603, the second-grained slag in the second temperature range is returned to the gasification unit 1 so that the second-grained slag in the second temperature range undergoes a gasification reaction in the gasification unit 1.

In the above operation S603, the cold slag unit 5 may also return the second-size slag in the second temperature range to the gasification unit 1 through the powder-returning port 53, so that the second-size slag in the second temperature range undergoes a gasification reaction in the gasification unit 1. The fluidizing cooling medium may include at least one of: saturated water vapor and carbon dioxide. The temperature of the carbon dioxide may range from 0 to 50 ℃. The fluidized cooling medium can also react with the slag in the first temperature range in the cold slag unit 5, and the slag in the first temperature range is cooled chemically in an endothermic manner by the gasification reaction.

In the above operation S603, the cold slag unit 5 may further add 1 to 3 layers of supplementary fluidized cooling medium inlets 55 in the axial direction of the cold slag unit 5, and the supplementary fluidized cooling medium inlets 55 introduce the fluidized cooling medium into the cold slag unit 5 in a tangentially inclined manner. The fluidized cooling medium is introduced in a tangential tilt-up mode by arranging the supplementary fluidized cooling medium inlet, the heat exchange between the fluidized cooling medium in the cold slag unit and the slag in the first temperature range is enhanced by driving the slag in the first temperature range to move, and the cooling effect of the cold slag unit on the slag in the first temperature range from the gasification unit is enhanced.

In the above operation S603, a spout fluidization device may be further employed in the cold slag unit 5, wherein the spout 56 and the fluidization port 57 are provided, and the spout 56 and the fluidization port 57 are used for introducing the fluidized cooling medium. The speed of the fluidized cooling medium introduced into the nozzle 56 can be 20-50 m/s, and the air speed of the small holes of the air distribution plate of the fluidizing port 57 can be 0.1-0.5 m/s. Through setting up spout fluidizer, can drive the slag in the first temperature range on both sides to middle fluidization mouth department and collect through letting in fluidization cooling medium in to the spout, when helping the fluidization mouth to let in fluidization cooling medium, central jet flow is big, strengthens the inner loop of the slag in the first temperature range, strengthens the heat transfer, and the cooling effect is better. In addition, a central guide shell 58 can be arranged in the spout-fluidizing device in the cold slag unit 5, and a heat exchange pipe is arranged in the area between the central guide shell 58 and the inner wall of the spout-fluidizing device. The lower edge of the central guide cylinder 58 is lower than the slag inlet 54 of the cold slag unit 5, and the upper edge thereof is flush with the lower edge of the discharge opening 52, so that it is possible to effectively prevent the first-size slag in the second temperature range from being unable to be separated from the second-size slag in the second temperature range and discharged through the discharge opening 52. The inner surface of the central guide shell 58 has an apparent wind speed of 4-8 m/s. The central flow can be strengthened by arranging the central guide cylinder, the ordered circulation of the air flow and the slag with the first particle size in the slag cooling unit is organized, the heat exchange is strengthened, and the cooling effect is enhanced. The heat exchange tubes are arranged in the area between the central guide cylinder and the inner wall of the spouted fluidized device, so that the central guide cylinder can be supported, heat exchange can be assisted, and the slag cooling effect is improved.

The above-mentioned embodiments, objects, technical solutions and advantages of the present invention are further described in detail, it should be understood that the above-mentioned embodiments are only examples of the present invention, and should not be construed as limiting the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. A cold sediment device of gasification, characterized by, includes:

a gasification unit for carrying out a gasification reaction of a fuel and a gasification agent in the gasification unit and producing slag in a first temperature range;

the slag cooling unit is provided with a fluidized cooling medium inlet, wherein the fluidized cooling medium inlet is used for introducing a fluidized cooling medium with a preset temperature and a preset wind speed, so that the slag in the first temperature range forms first-particle-size slag in a second temperature range and second-particle-size slag in the second temperature range under the action of fluidized transport and impact physical cooling of the fluidized cooling medium;

the cold slag unit is also provided with a powder returning port for returning the slag with the second particle size within the second temperature range to the gasification unit so that the slag with the second particle size within the second temperature range is subjected to gasification reaction in the gasification unit;

the gasification unit is provided with a secondary air port which is communicated with the powder return port, arranged in a transition area of a dilute phase area and a dense phase area of the gasification unit and used for introducing second-particle-size slag in a second temperature range into the transition area of the gasification unit.

2. The apparatus according to claim 1, characterized in that the cold slag unit is further provided with:

and the discharge opening is used for discharging the first-particle-size slag in the second temperature range.

3. The apparatus of claim 2, wherein:

the secondary air port is also used for introducing a secondary air gasifying agent;

the gasification unit is also provided with a primary air port for introducing a primary air gasifying agent.

4. The apparatus of claim 1, wherein:

the fluidizing cooling medium comprises at least one of: saturated water vapor, carbon dioxide;

the cold slag unit is also used for enabling the slag in the first temperature range and the fluidized cooling medium to generate a gasification reaction in the cold slag unit so as to carry out chemical cooling on the slag in the first temperature range in an endothermic mode through the gasification reaction.

5. The apparatus of claim 1, further comprising:

and the slag conveying device is used for conveying the slag in the first temperature range into the cold slag unit, wherein the slag conveying device is a device with adjustable conveying capacity.

6. The apparatus of claim 5, wherein:

a downcomer is arranged between the slag conveying device and the gasification unit and used for conveying the slag in the first temperature range into the slag conveying device, wherein a loosening air port is arranged in the downcomer and used for introducing loosening air into the downcomer.

7. The apparatus of claim 1, wherein:

the slag cooling unit is also provided with a supplementary fluidization cooling medium inlet for introducing supplementary fluidization cooling medium into the slag cooling unit, wherein the supplementary fluidization cooling medium is arranged on the side wall of the slag cooling unit, and the fluidization cooling medium inlet is arranged at the bottom of the slag cooling unit.

8. The apparatus of claim 1, wherein:

the cold slag unit adopts a spout fluidization device, wherein the spout fluidization device is provided with a spout and a fluidization port, and the spout and the fluidization port are used for introducing the fluidized cooling medium; the central guide cylinder is further arranged in the spouted fluidizing device, and a heat exchange tube is arranged in an area between the central guide cylinder and the inner wall of the spouted fluidizing device.

9. A method for carrying out cold slag gasification by using the cold slag gasification device of any one of claims 1 to 8, which is characterized by comprising the following steps:

feeding slag from the gasification unit in a first temperature range to a cold slag unit;

introducing a fluidized cooling medium with a preset temperature and a preset wind speed into the slag cooling unit, so that the slag in the first temperature range forms first-particle-size slag in a second temperature range and second-particle-size slag in the second temperature range under the action of fluidized transport and impact physical cooling of the fluidized cooling medium;

returning the second-particle-size slag in the second temperature range to the gasification unit so that the second-particle-size slag in the second temperature range undergoes a gasification reaction in the gasification unit.

10. The method of claim 9, wherein:

the fluidizing cooling medium comprises at least one of: saturated water vapor, carbon dioxide;

the method further comprises the following steps: the slag and the fluidized cooling medium in the first temperature range undergo a gasification reaction in the cold slag unit so as to chemically cool the slag in the first temperature range in an endothermic manner by the gasification reaction.

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