CN100366710C - Multi-nozzle coal-water slurry or pulverized coal gasifier and its industrial application - Google Patents

Abstract

The invention designs a multi-nozzle coal water slurry or pulverized coal gasification furnace for coal water slurry or pulverized coal gasification. The gasification chamber is composed of a shell, a process nozzle chamber, a process nozzle, a preheating burner chamber, and a preheating burner. Slag mouth composition. The carbon conversion rate of this gasifier is over 98%, and the investment is low. It is especially suitable for large-scale coal gasification production processes with a daily processing capacity of 3,000 to 5,000 tons, and is used in the fields of methanol, synthetic ammonia, and IGCC power generation.

Description

Multi-nozzle coal-water slurry or pulverized coal gasifier and its industrial application

technical field

The invention relates to a gasification furnace used for gasifying coal-water slurry or pulverized coal, and relates to a multi-nozzle gasification furnace.

Background technique

The clean and efficient utilization of coal is a major technical issue in the field of energy and environmental protection in the world today, and it is also one of the key technologies for the sustainable development of my country's national economy. Coal gasification is the main way to convert primary energy into clean secondary energy, and its products are fuel gas (coal gas), synthesis gas, reducing gas, hydrogen, and carbon monoxide. Coal gasification technology has been widely used in the fields of combined cycle (IGCC) power generation unit, synthetic ammonia and methanol industry, production of acetic acid and acetic anhydride by carbonylation, production of sponge iron, preparation of pure carbon monoxide, and preparation of pure hydrogen. application, and the gasifier is the key equipment for coal gasification. For this reason, many scientific and technical personnel have researched and developed various types of gasifiers. At present, in the gasification technology using entrained bed (spouted bed, entrained bed), there are mainly two representative ones: the gasifier using coal-water slurry as raw material has Texaco (now GE company); the gasifier using pulverized coal as raw material has Shell. Documents U.S. Pat. Nos. 4,637,823, 4,527,997, and 5,281,243 respectively disclose Texaco gasifiers. The geometric characteristics of the gasifiers are that the nozzle axis coincides with the coal gas and liquid slag outlet axes, and both are on the main axis of the gasifier . In view of the fact that the gasifier is an entrained bed, some materials (streams) are short-circuited. The applicant's experimental test shows that if the average residence time of the materials in this type of gasifier is 5 seconds, in fact, some of the materials will escape out of the furnace after the residence time of less than 1 second, and the other part of the materials will stay in the furnace for a long time. more than 5 seconds. That is to say, the residence time of the materials in the gasifier has a very wide distribution, and 50% to 60% of the materials are less than the average residence time and escape out of the furnace. The carbon conversion rate of the Texaco gasifier is generally less than 95%, and the water vapor decomposition rate is also less than 20%; the document U.S.92-960345 discloses the Shell gasifier. The gas and liquid slag flow in opposite directions, that is, the gas is upward and the liquid slag is downward. It has two disadvantages. First, the liquid slag is easily solidified and blocked the slag outlet due to the apathetic gas. Second, the fine coal slag suspended in the gas flow has to go through a long pipeline and change the flow direction before entering When downstream equipment is used for waste heat recovery or gas-solid separation, pipelines and downstream equipment are prone to blockage, both of which will shorten the operating cycle. In view of the defects of the above two furnace types, Chinese patent 98110601.3 discloses a multi-nozzle opposed coal-water slurry or pulverized coal gasifier. The device (1150 tons/day) is in operation, and the carbon conversion rate of the gasifier is over 98%, which is 3 percentage points higher than that of the Texaco furnace; The gasification rate is above 98%, and various process indicators such as specific oxygen consumption and specific coal consumption have shown very good gasification performance. Practice has proved that the gasifier still has room for improvement. The current gasifier cannot meet the needs of modern production enterprises for coal gasification technology with a daily processing capacity of more than 3,000 tons of coal. Processing power can be further improved.

Contents of the invention

The technical problem to be solved in the present invention is to disclose a multi-nozzle coal water slurry or pulverized coal gasification furnace and its industrial application, so as to meet the needs of modern production enterprises for coal gasification technology with a daily processing capacity of 3,000 tons or more.

The idea of the present invention is as follows: the gasification effect of coal water slurry and pulverized coal is not only related to the physical and chemical properties of the coal, but also related to the structure and size of the nozzle and the nozzle size under certain process conditions. The fluid flow behavior and flow field structure formed when the configuration, gasifier structure and size, and the matching of the three are related to gasification. That is to say, when the coal type and process conditions are fixed, the gasification effect mainly depends on the concentration distribution, temperature distribution and residence time distribution in the furnace. At the high temperature of the gasifier, the chemical reaction rate is quite fast, and the gasification process is controlled by the heat and mass transfer process, and the transfer process and residence time distribution mainly depend on the fluid behavior and flow field structure in the furnace. Raw coal (coal-water slurry or dry coal powder) or other hydrocarbon fuels and gasification agents enter the furnace through nozzles in jet flow, and the jet streams from different nozzles collide with each other in the furnace. Because of inertia, the fuel particles are in the furnace. Multiple damping oscillations are generated to increase the residence time of fuel particles in the furnace and improve the residence time distribution; at the same time, the turbulence intensity is significantly increased, which greatly increases the heat and mass transfer rate, thereby improving the carbon conversion rate of fuel and water vapor. decomposition rate. At the same time, in order to overcome the limitation of the maximum pipe diameter allowed by the slag breaker on the processing capacity of the gasifier, multiple slag lowering ports are set at the bottom of the washing and cooling chamber.

The multi-nozzle coal water slurry or pulverized coal gasification furnace used for coal water slurry or pulverized coal gasification of the present invention includes a gasification chamber and a washing and cooling chamber;

The gasification chamber includes a cylindrical shell lined with refractory bricks, a process nozzle chamber, a process nozzle, a preheating burner chamber and a preheating burner. The preheating burner chamber is arranged on the top of the gasification chamber. The nozzle is vertically arranged in the preheating burner chamber, and its axis coincides with the axis of the gasification chamber. The process nozzle chamber is evenly distributed along the periphery of the shell. The process nozzle is mechanically installed in the process nozzle chamber, and the gasification slag port is set in the The bottom of the gasification chamber is used to discharge the gasification slag out of the gasification chamber;

The washing and cooling chamber is arranged at the lower part of the gasification chamber, and the washing and cooling chamber includes a quenching ring, a downcomer, a bubble breaking bar and a lower slag outlet, and the said quenching ring is arranged below the gasification slag outlet of the gasification chamber, The downcomer is arranged under the chilling ring to discharge the gasification slag into the washing and cooling chamber. The bubble breaking bar is arranged around the downcomer to break gas bubbles and increase the gas-liquid contact area. On the upper part of the cooling chamber, the lower slag outlet is set at the bottom of the washing and cooling chamber;

Said process nozzle can adopt conventional nozzle, such as when coal water slurry is used as raw material, a kind of "three-channel combined coal water slurry gasification nozzle with cyclone" disclosed in Chinese patent 95111750.5 can be preferably used; If pulverized coal is used as the raw material, a "synthesis gas nozzle prepared by partial oxidation of solid carbonaceous matter" disclosed in Chinese patent 200510025050.6 can be preferentially used. The shell of the gasifier is also provided with several thermocouple holes and surface thermometers. The washing and cooling chamber can preferably adopt a kind of "composite bed high temperature gas cooling and washing equipment" invented by Chinese patent 01112880.1.

It is characterized in that the process nozzle is inclined downward, and there are at least two slag lowering ports.

The multi-nozzle coal-water slurry or pulverized coal gasifier of the present invention can be used for the gasification of coal-water slurry or pulverized coal, and the specific application method is as follows:

The coal-water slurry or pulverized coal and gasification agent are sent into the gasification furnace through the process nozzle, the gasification pressure is 4-10MPa, and the gasification temperature is 1300-1500°C. When coal water slurry is used as raw material, the gasification agent can be oxygen, etc., and the weight ratio of coal water slurry to oxygen is 1.3 to 2.7; when pulverized coal is used as raw material, the gasification agent can be oxygen, water vapor or carbon dioxide, etc. , the weight ratio of pulverized coal to oxygen is 0.9-1.6.

The multi-nozzle coal-water slurry or pulverized coal gasification furnace for coal-water slurry or pulverized coal gasification of the present invention has obvious advantages, the temperature distribution in the furnace is uniform, the carbon conversion rate of the gasification furnace is more than 98%, and the investment is low. It is especially suitable for large-scale coal gasification production processes with a daily processing capacity of 3,000 to 5,000 tons, and can be used in methanol, synthetic ammonia, IGCC power generation and other fields.

Description of drawings

Figure 1 Schematic diagram of the structure of the gasifier.

Figure 2 is a schematic diagram of the process nozzle structure when pulverized coal is used as raw material.

Detailed ways

Referring to Fig. 1, the multi-nozzle coal-water slurry or pulverized coal gasifier for coal-water slurry or pulverized coal gasification of the present invention includes a gasification chamber 1 and a washing and cooling chamber 2;

Said gasification chamber 1 includes a cylindrical shell 3 lined with refractory bricks, a process nozzle chamber 4, a process nozzle 5, a preheating burner chamber 6 and a preheating burner 7, and the preheating burner chamber 6 is arranged on the gas On the top of the gasification chamber 1, the preheating burner 7 is vertically arranged in the preheating burner chamber 6, and its axis coincides with the axis of the gasification chamber 1. The process nozzle chamber 4 is evenly distributed along the periphery of the shell 3. installed in the process nozzle chamber 4, the gasification slag port 10 is set at the bottom of the gasification chamber 1, and several brick brackets 17 with a layer spacing of 1m are arranged in the refractory brick 8;

Said washing and cooling chamber 2 is arranged at the lower part of the gasification chamber 1, and the washing and cooling chamber 2 includes a quenching ring 11, a downcomer 12, a bubble breaking strip 13 and a slag outlet 14, and said quenching ring 11 is arranged at the gasification chamber 1. Below the gasification slag port 10 of the chamber, the downcomer 12 is arranged below the chilling ring 11, the bubble breaking bar 13 is arranged around the downcomer 12, the gas outlet 16 is arranged on the upper part of the washing and cooling chamber 2, and the lower slag port 14 It is arranged at the bottom of the washing and cooling chamber 2; it is characterized in that:

(1) The process nozzle is inclined downward, and the preferred angle α between the axis of the process nozzle 5 and the horizontal plane is 1-45°;

(2) There are at least two lower slag outlets 14, preferably 2 to 4.

Fig. 2 is a schematic structural view of the process nozzle when pulverized coal is used as raw material, which has been disclosed in Chinese patent 200510025050.6. As can be seen from the figure, the pulverized coal process nozzle includes a coaxial outer ring nozzle 18, an inner nozzle 19, and a nozzle center conduit 20 and nozzle outer ring conduit 21;

Said nozzle outer ring conduit 21 is connected with the outer ring nozzle 18, said nozzle central conduit 20 is connected with the inner nozzle 19, and the inner nozzle 19 is arranged in the outer ring nozzle 18, and the inner shrinkage half angle γ of the inner nozzle 19 is 3～60°, the lateral inclination angle β of the inner nozzle 19 is 30～80°, the inner contraction half angle ε of the outer nozzle 18 is 30～80°, the ratio of the nozzle diameter d of the inner nozzle 19 to the straight section height h of the nozzle is h: d=1:0.5-10, the distance S between the nozzle end faces of the inner nozzle 19 and the outer nozzle 18 is 0-20 mm.

Example 1

A multi-nozzle coal-water slurry gasifier with a daily processing capacity of 3,000 tons of coal, the gasification pressure is 6.5MPa, the inner diameter of the gasification chamber shell is Φ4400mm, and there are three slag lowering ports 14. The coal-water slurry process nozzle adopts the patent 95111750.5 For the proposed structure, the angle α between the axis and the horizontal plane is 10°;

The gasification agent is oxygen, the total oxygen consumption is 82192Nm ³ /h, the gasification temperature is 1350°C, the weight ratio of coal water slurry to gasification agent is 1.77, and the total gas flow out of the gasification chamber is 301476Nm ³ /h.

Coal Composition

Calorific value (kJ/kg) 27765 Elemental analysis (wt%) CHNSOClAsh 67.594.371.222.307.550.02216.748

Composition of gas out of gasification chamber (vol%)

H₂COCO₂H₂SCOSCH₄N₂ArNH₃HCNHCOOHHCl(ppm)O₂H₂O 25.9537.9013.700.630.030.020.310.100.210050.0021.15

Example 2

A multi-nozzle pulverized coal gasifier with a daily processing capacity of 3,000 tons of coal. The gasification pressure is 4.0MPa. The inner diameter of the gasification chamber shell is Φ4200mm. There are three slag lowering ports 14. The nozzle adopts the structure shown in Figure 2. The axis and the horizontal plane are clamped The angle α is 10°;

The gasification agent is oxygen and water vapor, the total consumption of oxygen is 70000Nm ³ /h, the total consumption of steam is 22500kg/h, the gasification temperature is 1350℃, the weight ratio of pulverized coal to oxygen is 1.25, the total flow rate of gas out of the gasification chamber 264175Nm ³ /h.

Coal Composition

Water (wt%) 2 Elemental Analysis (dry base wt%) CHNSOAsh 69.274.561.283.68.0813.21

Composition of gas out of gasification chamber (vol%)

H₂(v)% 29.54 CO(v)% 58.39 CO₂(v)% 2.36 H₂S(v)% 1.10 COS(v)% 0.09 CH₄(v)% 0.06 N₂(v)% 4.46 NH₃(v)% 0.00 NH₃(v)% 0.01 HCN(v)% 0.00 HCOOH(v)% 0.00 HCl(v)% O₂(v)% H₂O(v)% 3.99

Claims (8)

1. multi-nozzle coal water slurry or powder coal gasification furnace comprise vaporizer (1) and scrubbing-cooling chamber (2);

Said vaporizer (1) comprises cylindrical shell (3), technology nozzle box (4) and the technology nozzle (5) of inner lining refractory block (8), technology nozzle box (4) is uniform along housing (3) periphery, technology nozzle (5) mechanically is installed in the technology nozzle box (4), and gasification cinder notch (10) is arranged on vaporizer (1) bottom;

Said scrubbing-cooling chamber (2) is arranged on vaporizer (1) bottom, and scrubbing-cooling chamber (2) comprises cinder notch (14) down, and gas exit (16) is arranged on the top of scrubbing-cooling chamber (2), it is characterized in that:

(1) technology nozzle (5) is downward-sloping;

(2) cinder notch (14) has two at least down;

(3) establish brick-supporting rack (17) in the fire brick layer (8);

Technology nozzle (5) axis and horizontal plane angle α are 10 °.

2. the multi-nozzle coal water slurry or the powder coal gasification furnace of coal water slurry according to claim 1 or coal gasification is characterized in that, following cinder notch (14) has 2～4.

3. the multi-nozzle coal water slurry or the powder coal gasification furnace of coal water slurry according to claim 2 or coal gasification, it is characterized in that, said fine coal technology nozzle comprises co-axial outer shroud shower nozzle (18), interior shower nozzle (19), nozzle center's conduit (20) and nozzle outer shroud conduit (21), said nozzle outer shroud conduit (21) is connected with outer shroud shower nozzle (18), said nozzle center conduit (20) is connected with interior shower nozzle (19), and interior shower nozzle (19) is arranged in the outer shroud shower nozzle (18).

4. the multi-nozzle coal water slurry or the powder coal gasification furnace of coal water slurry according to claim 3 or coal gasification, it is characterized in that, said scrubbing-cooling chamber (2) also comprises chilling ring (11), and said chilling ring (11) is arranged on gasification cinder notch (10) below of vaporizer (1).

5. the multi-nozzle coal water slurry or the powder coal gasification furnace of coal water slurry according to claim 4 or coal gasification is characterized in that, said scrubbing-cooling chamber (2) also comprises downtake (12), and downtake (12) is arranged on chilling ring (11) below.

6. the multi-nozzle coal water slurry or the powder coal gasification furnace of coal water slurry according to claim 4 or coal gasification is characterized in that, said scrubbing-cooling chamber (2) also comprises foam-breaking strip (13), and said foam-breaking strip (13) is arranged on downtake (12) periphery.

7. the multi-nozzle coal water slurry or the powder coal gasification furnace of coal water slurry according to claim 1 or coal gasification is characterized in that, establish brick-supporting rack (17) in the said fire brick layer (8), brick-supporting rack (17) spacing 1m, and brick-supporting rack (17) is fixed on the housing (3).

8. according to the application of each described multi-nozzle coal water slurry of claim 1～7 or powder coal gasification furnace, it is characterized in that, be used for the gasification of coal water slurry or fine coal.

Images