CN101698805B - Dry process coaling slag film gasifier - Google Patents

Abstract

The invention relates to a dry-process coal slag film gasifier, which is characterized in that it includes a liquid slag discharge device, the upper side of the liquid slag discharge device is connected to a slag pool, and the upper side of the slag pool is connected to the lower section of a radiation cooling chamber; the lower section of the radiation cooling chamber There is a slag catcher inside; the outer middle part of the lower section of the radiation cooling chamber is connected to at least one slag film gasification device, the slag film gasification device is cylindrical, with a dry coal inlet in the axial direction and an air inlet channel in the tangential direction; The upper side of the lower section of the radiation cooling chamber is connected to the upper section of the radiation cooling chamber through the waist, the upper section of the radiation cooling chamber is connected to the upper end of the convection cooling device, the lower end of the convection cooling device is connected to the dust removal equipment, and the dust removal device is connected to the purification equipment. The invention has the advantages of high gasification intensity, fast start-up speed, high load regulation ratio, high slag collection rate, high equipment efficiency, low coal quality requirements, high cold gas efficiency, high energy utilization efficiency and low system investment.

Description

A kind of dry method adding coal slag membrane gasifier

technical field

The invention relates to a dry method adding coal slag membrane gasification furnace, which belongs to the technical field of coal gasification equipment in the field of energy and chemical industry.

Background technique

Dry pulverized coal pressurized gasifier is a large-scale pulverized coal gasification technology developed at the end of the 20th century. It has a significant competitive advantage over previous coal gasification technologies.

At present, the coal gasification technology that has been industrialized can be divided into three categories, namely fixed bed gasification technology, fluidized bed gasification technology and entrained bed gasification technology. The gasification temperature and pressure of the entrained bed gasifier are high, the load is large, and the coal type is suitable for a wide range. It is the mainstream of the development of coal gasification technology at present. The gasification intensity of fixed bed gasifier and fluidized bed gasifier is relatively low, which is not suitable for large-scale coal gasification. The coal gasification entrained bed coal gasification technology that has been industrialized abroad mainly includes GE (Texaco) gasification technology using coal water slurry as raw material, Shell gasification technology using dry pulverized coal as raw material, Prenflo gasification technology, GSP gasification technology, etc. Compared with the Shell furnace, the Texaco gasifier, which uses coal water slurry as raw material, has higher oxygen consumption and lower cold gas efficiency, but their investment is basically the same. Therefore, the gasifier technology using dry coal as raw material will be the mainstream direction of gasifier development in the future.

Several typical types of dry pulverized coal pressurized entrained flow bed furnaces that are now industrialized are:

(1) K-T gasifier: Atmospheric pressure gasification, pure oxygen as gasification agent, liquid slag discharge, non-full water wall structure. Most of them operate with double burners and four nozzles, and the oxygen consumption is high. In order to recover the sensible heat of the gas, the required heat exchange equipment is large and uneconomical, and the dust removal efficiency under low pressure is not high.

(2) Shell gasifier: equivalent to a pressurized K-T furnace, nitrogen transports dry coal powder, pure oxygen as gasification agent, upward air flow, liquid slag discharge, membrane water wall structure gasifier. A variety of coals can be burned, the carbon conversion rate is as high as 98%, the product has a high content of combustible gas, and the gasification product has no tar. The production capacity of the gasifier is large, up to 3000t/d.

(3) GSP gasifier: high-pressure gasifier, down-spray type, adopts pulverized coal, oxygen blast, dry coal powder feed, liquid slag discharge, and the furnace lining adopts a water-cooled wall structure. Developed by the German Fuel Research Institute, the operating pressure is 2.5-3.0MPa, the nozzle and water-cooled fireplace lining have a long service life (it is said that it can reach more than 5 years), and it can gasify various coal types.

In the existing dry powder gasification furnace, the gasification process is mainly carried out in the space of the gasification chamber, which is called suspension gasification. The characteristics of the above three dry powder entrained bed gasifiers are: because the liquid slag is used, the gasifier operates under high temperature and high pressure conditions, the raw material coal has a wide range of application, the carbon conversion rate is high (>90%), and the gas is generally free. Tar and phenols, less environmental pollution. The water-cooled wall is used in the furnace, which prolongs the service life of the heat-resistant materials in the furnace.

In order to improve the carbon conversion rate, cold gas efficiency and total thermal efficiency of the gasifier, on the basis of dry powder gasification, a segmented dry coal powder gasifier has been developed. The gasification furnace is divided into two sections, and the lower furnace section About 80% of dry coal powder undergoes gasification reaction with oxygen and steam, and about 20% of dry coal powder and steam are injected into the upper furnace section, and after pyrolysis and gasification reaction with the high-temperature gas generated in the lower furnace section, it can be Increase the combustible components of the gas, increase the calorific value, and cool the high-temperature gas, which helps the molten ash in the gas to solidify and separate from the gas. However, during suspension gasification, the reaction speed depends on the diffusion speed of the gas, and the relative velocity between the pulverized coal and the gas flow is extremely low. Therefore, it is more difficult to continue to increase the gasification intensity; and because the entrained bed gasifier mainly takes place in the space Gasification, the slag collection rate of this type of gasifier is difficult to reach a high level; in addition, this type of gasifier has strict requirements on the fineness of coal powder, and the pulverization system is relatively complicated. This type of gasifier is usually a single gasification chamber, so the start-up speed and variable load adjustment capacity of the gasifier are relatively low.

To sum up, fixed bed and fluidized bed gasifiers are not suitable for large-scale gasifiers due to their low gasification intensity and low carbon conversion rate; while entrained bed gasifiers use suspension gasification, gasification The process is seriously affected by the flow state in the gasification chamber, especially the load regulation ratio and start-up speed of entrained gasification, and the slag collection rate of the existing suspension gasifier is low, resulting in high dust removal load of crude gas; In the gasification furnace with liquid coal addition, since a large amount of liquid water enters the gasification furnace along with the coal powder, the oxygen consumption of the gasification furnace is high and the efficiency of cold gas is low. The above-mentioned types of gasifiers are not conducive to further improving the gasification intensity, reducing the size of the gasifier, flexible operation, large load adjustment ratio, fast start-up speed, high cold gas efficiency, high carbon conversion rate, long service life, high reliability, etc. The goal pursued by the coal gasifier industry.

Contents of the invention

The purpose of the present invention is to provide a system with high gasification intensity, fast start-up speed, high load regulation ratio, high slag collection rate, high equipment efficiency, low coal quality requirements, high cold gas efficiency, high energy utilization efficiency and A low-investment pressurized dry method feeds the coal slag film gasifier.

In order to achieve the above object, the technical solution of the present invention is to provide a dry-process coal slag film gasifier, which is characterized in that it includes a liquid slag discharge device, the upper side of the liquid slag discharge device is connected to the slag pool, and the upper side of the slag pool is connected to The lower part of the radiation cooling chamber; the inside of the lower part of the radiation cooling chamber is equipped with a slag catcher; the outer middle part of the lower part of the radiation cooling chamber is connected to at least one slag film gasification device, and the slag film gasification device is cylindrical, and its axial direction is provided with a dry coal inlet , with an air inlet channel tangentially; the upper side of the lower section of the radiation cooling chamber is connected to the upper section of the radiation cooling chamber through the waist, the upper section of the radiation cooling chamber is connected to the upper end of the convection cooling device, the lower end of the convection cooling device is connected to the dust removal equipment, and the dust removal equipment is connected to the purification equipment .

Further, the slag film gasification device is installed vertically or obliquely upward, and its inclination angle α is 5-15 degrees.

The upper section of the radiation cooling chamber, the waist, the lower section of the radiation cooling chamber and the outside of the convection cooling device are all provided with pressure-bearing shells.

The dry coal slag film gasification furnace involved in the present invention adopts high-pressure pure oxygen and steam gasification, dry coal or carbon dioxide powder feeding, and the coal gasification process is in a vertical or horizontal slag film gasification device The gasification furnace complies with the development direction of coal gasification technology. This gasifier can be equipped with one or more slag film gasification devices, which are generally arranged symmetrically to the center. The dry coal is fed into the gasifier along the axial direction of the slag film gasification device through the high-pressure feeder, or sent into the gasifier along the tangential or tangential direction of the slag film gasification device through the carbon dioxide gas flow.

The molten slag produced under high temperature and high pressure flows down along the inner wall of the slag film gasification device due to the combined action of gravity and air flow fluid power. Coal powder, coal particles or coal chips are gasified with gasification agent after volatile matter is precipitated on the surface of high-temperature slag, which is called slag film gasification. The gasification process is somewhat similar to the molten bed gasification furnace, but the molten slag layer of the slag film gasification of the present invention is thinner, and the relative gasification surface area is larger. The surface temperature of the slag is very high, which can gasify coal with a large particle size; almost all combustible components in the pulverized coal are gasified at high temperature, which has a high gasification efficiency; The short gasification reaction time can fully decompose tar and phenols, and simplify the gas purification process and equipment. The gas pressure range in the pressurized gasifier is 2-9MPa, the crude gas temperature of the slag film gasification device is 1200-1400°C, the slag is collected in the slag pool and discharged in liquid form through the slag discharge device, and the high-temperature crude gas is In the radiation cooling chamber, the heat is exchanged to the water wall to cool down, and the sensible heat is used. After this process, the temperature of the crude gas drops below 940°C. Subsequently, the crude gas is introduced into the convection cooling section, and the temperature is lowered to below 300°C through a heat exchanger. After a series of purification processes such as dedusting, desulfurization, deammonization and dehydration by dust removal equipment and purification equipment, the crude gas becomes a clean room with a temperature of about 50°C. Gas, for further use.

Compared with the prior art, the present invention has the following prominent features and significant advantages:

(1) The present invention can adopt the pressurized gasification method of _N2 or _CO2 carrying pulverized coal as feedstock, when adopting the pressurized gasification method of _CO2 carrying pulverized coal as feedstock, not only the gasification efficiency of coal is high (The conversion rate of carbon is as high as 97%), and it can adapt to different grades of coal. There is no strict limit on the calorific value of coal, especially the ash melting point of coal, and the purity of the produced reducing gas is very high (CO+H ₂ ≥ 90%), high cold gas efficiency. The particle size range of pulverized coal is wide, and coal dust can also be used as raw material, which can reduce the energy consumption of pulverizing equipment.

(2) Since the water-cooled wall is arranged in the high-pressure pressure-bearing shell, the temperature of the high-temperature crude gas is reduced by using a radiant cooler, and the heat exchange is mainly completed by the water-cooled wall, which can cancel the cold gas recirculation system.

(3) The gasification strength of the slag film is high, which can reduce the size of the gasifier. The slag film gasification device of the gasifier can be divided into one or more, and each slag film gasification device can operate independently, so the startup speed is fast and the load regulation performance is good.

(4) Adopt slag film gasification, liquid slag discharge, and set slag catcher, so the slag catch rate is high, which is beneficial to reduce the dust accumulation and slagging of heat recovery equipment, improve the working conditions of heat recovery equipment, and reduce the burden of dust removal equipment .

(5) The slag film gasification device can be arranged vertically or horizontally, which is beneficial to reduce the height of the gasifier and facilitate coal addition.

Description of drawings

Fig. 1 is the structural schematic diagram of dry method adding coal slag membrane gasifier;

Fig. 2 is a sectional view of the slag film gasification device.

Detailed ways

The present invention will be described in detail below in conjunction with the examples.

Example

As shown in Figure 1, it is a schematic structural diagram of a dry process adding coal slag film gasifier, and the dry process adding coal slag film gasifier consists of a pressure-bearing shell 1, a dry coal inlet 2, an air inlet channel 3, and a slag film gasification device 4. Slagging pipe 5, lower section of radiation cooling chamber 6, slag pool 7, liquid slag discharge device 8, waist 9, upper section of radiation cooling chamber 10, convection cooling device 11, coolant inlet 12, coolant outlet 13, dust removal equipment 14 and purification equipment 15 to form.

The upper side of the liquid slag discharge device 8 is connected to the slag pool 7, and the upper side of the slag pool 7 is connected to the lower section 6 of the radiation cooling chamber; the lower section 6 of the radiation cooling chamber is provided with a slag filling pipe 5, and one end of the slag filling pipe 5 is connected to the radiation cooling chamber The side wall of the lower section 6 is connected with the bottom wall of the lower section 6 of the radiation cooling chamber at the other end; There is a dry coal inlet 2, as shown in Figure 2, which is a cross-sectional view of the slag film gasification device, and the tangential direction of the slag film gasification device 4 is provided with an air inlet channel 3; the upper side of the lower section 6 of the radiation cooling chamber is connected through a waist 9 The upper section 10 of the radiation cooling chamber, the upper section 10 of the radiation cooling chamber is connected to the upper end of the convection cooling device 11 , the lower end of the convection cooling device 11 is connected to the dust removal device 14 , and the dust removal device 14 is connected to the purification device 15 . The slag film gasification device 4 is arranged obliquely upward, and its inclination angle α is 10 degrees. The upper section 10 of the radiation cooling chamber, the waist 9 , the lower section 6 of the radiation cooling chamber and the outside of the convection cooling device 11 are respectively provided with a pressure-bearing shell 1 .

The method of using the above-mentioned device is as follows:

Step 1. Send oxygen and water vapor tangentially into the slag film gasification device 4 with a pressure of 4 MPa and a temperature of 1400°C through the air inlet channel 3, and the coal chips are dried axially through the dry coal inlet 2 through the high-pressure coal feeder sent to the slag film gasification device 4, under the action of the rotating air flow and the high temperature heating condition of the slag film, high temperature pure oxygen water vapor gasification occurs, and high temperature and high pressure crude gas is generated after 15-30s; the coal supply is 2000t/ d, The feed rates of oxygen and water vapor are 1400t/d and 280t/d respectively.

Step 2. The high-temperature and high-pressure crude gas first passes through the slag catcher 5 and the lower section 6 of the radiant cooler, and then the temperature drops to 1000°C. At the same time, the liquid slag flows into the slag pool 7 at the bottom in the lower section 6 of the radiant cooling chamber, and then passes through the slag discharge The device 8 discharges the slag.

Step 3. The crude gas at 1000°C passes through the waist 9 and the upper section 10 of the radiant cooler in turn, and after cooling down to below 940°C, it passes through the convection cooling device 11 to cool the gas to below 300°C;

Step 4. The crude gas cooled to below 300°C enters the dedusting equipment 14 and purification equipment 15 for desulfurization, denitrification and dehydration, and becomes clean gas at 50°C for use.

In the radiation cooling chamber, a water-cooled wall is arranged in the pressure-bearing shell 1 to reduce the temperature of the high-temperature crude gas to a certain temperature in the form of radiation heat exchange. In the present invention, the radiation cooling chamber is divided into the upper section 10 of the radiation cooling chamber by the waist 9 arranged therein. and lower section 6 of the radiative cooling chamber. The raw material coal or gasified biomass, petroleum coke and other hydrocarbons required by the gasifier enter the gasifier in dry granular or chip form from the dry coal inlet 2 of the horizontal slag film gasification device 4 . Gasification agent pure oxygen and water vapor enter the gasification furnace tangentially from the air inlet channel 3 of the slag film gasification device 4 , and form a swirling airflow in the slag film gasification device 4 . Water-cooled walls are arranged around the pressure-bearing shell 1 of the slag-film gasification device 4, and the water-cooled walls are covered with heat-insulating and heat-resistant materials, such as silicon carbide and aluminum silicate. The thickness of the layer is 20-40mm and the temperature is 1200-1800°C. The liquid slag film, the coal mainly reacts with the gasification agent on the surface of the slag film under the action of tangential air supply, and a small amount of fine coal powder particles can also Suspended gasification occurs with the gasification agent in the space in the gasification device 4 . The slag produced by the coal gasification reaction flows from top to bottom under the action of gravity and enters the lower section 6 of the radiation cooling chamber. The inside of the water-cooled wall in the lower section 6 of the radiation cooling chamber is arranged with heat-insulating materials and refractory materials, such as silicon carbide and aluminum silicate, and a slag catcher 5 is arranged to catch the molten fly ash from the gasification device, and the slag catcher Inside 5 is flowing cooling water, whose inlet and outlet are respectively connected to the cooling water system. Increase the temperature level in the lower section 6 of the radiation cooling chamber through the above measures, further increase the gasification rate in this section, liquid slag discharge, and further improve the slag collection rate, so that the slag collection rate is not lower than 70%. A molten slag pool 7 is arranged at the bottom of the lower section 6 of the radiation cooling chamber, that is, the bottom of the gasifier, and the molten slag is discharged from the gasifier through a slagging device 8 . While the high-temperature gas generated by the slag film gasification device is cooled in the lower section 6 of the radiation cooling chamber, the incompletely gasified coal is further gasified in the lower section 6 of the high-temperature radiation cooling chamber, and the gas after the gasification reaction passes through the waist 9 Enter the upper section 10 of the radiant cooling chamber to exchange heat with the surrounding water-cooled wall, and after the temperature of the gas is lowered to below 940°C, it is passed into the convection cooling device 11 to further reduce the temperature, and then passes through the dust removal equipment 14 and the purification equipment 15 for dust removal. Output after purification. Dust removal equipment and purification equipment are selected according to the subsequent process flow.

Gained gas composition (volume percent) sees the following table:

Example 2

Similar to Embodiment 1, the difference is that the slag film gasification device 4 is vertically arranged.

Example 3

Similar to Example 1, the difference is that the slag film gasification device 4 is arranged obliquely upward, and its inclination angle α is 5 degrees.

Example 4

Similar to Example 1, the difference is that the slag film gasification device 4 is arranged obliquely upward, and its inclination angle α is 15 degrees.

Claims (2)

1. a dry process coaling slag film gasifier, is characterized in that, comprises liquid state slag discharging device (8), and the upside of liquid state slag discharging device (8) is communicated with slag bath (7), and the upside of slag bath (7) is communicated with radiant cooling room hypomere (6); The inside of radiant cooling room hypomere (6) is provided with screen tube (5); The outer middle side part of radiant cooling room hypomere (6) is communicated to a few slag film gasification installation (4), and slag film gasification installation (4) is cylindrical, and it is axially arranged with dry coal import (2), tangentially is provided with air intake passage (3); The upside of radiant cooling room hypomere (6) is communicated with radiant cooling room epimere (10) via waisting (9), radiant cooling room epimere (10) is communicated with the upper end of convection cooling device (11), the lower end of convection cooling device (11) is communicated with dust removal installation (14), dust removal installation (14) is communicated with treating plant (15), described slag film gasification installation (4) vertically or obliquely arranges, and its tilt angle alpha is 5～15 degree.

2. dry process coaling slag film gasifier as claimed in claim 1, it is characterized in that, all be provided with bearing shell (1) outside described radiant cooling room epimere (10), waisting (9), radiant cooling room hypomere (6) and convection cooling device (11).

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