CN111187644A - Pressurized slag gasifier with coupled plasma torch and steam oxygen nozzle - Google Patents

Abstract

The invention relates to a pressurized slag gasifier with a plasma torch and a steam oxygen nozzle coupled, wherein a steam nozzle, an oxygen nozzle and a plasma torch are arranged in a slag area at the lower part of the gasifier. The invention utilizes the plasma torch to provide heat when the gasification furnace is shut down, melts the coal ash, solves the problem that the slag is solidified and agglomerated to block the lower cone and the slag discharge port of the gasification furnace when the gasification furnace is stopped due to failure, greatly shortens the shut-down time, and improves the operation period of the gasification furnace, thereby improving the economy of coal gasification production.

Description

Pressurized slag gasifier with coupled plasma torch and steam oxygen nozzle

Technical Field

The invention relates to a pressurized slag gasifier, in particular to a pressurized slag gasifier with a plasma torch and a steam oxygen nozzle coupled.

Background

The coal gasification technology is the core for developing clean and efficient coal conversion technology, is the leading point of coal chemical industry, and is an important foundation for developing a large number of chemical products (chemical fertilizers, methanol, natural gas, olefin and the like), a poly-generation system and IGCC power generation. The crushed coal pressurized slag gasification technology (BGL gasification furnace) has attracted much attention in recent years and realized industrial application due to its many remarkable advantages of high gasification intensity, large single furnace capacity, low steam consumption, low wastewater amount, etc.

The crushed coal pressurized slag gasifier is operated in the running process, the slag on the slag discharge short section is gradually accumulated more and more, the slag hanging is increased more and more, the slag discharge amount is reduced along with the slag hanging, the slag flow during slag spraying is deflected, the slag flow is thinner and thinner, the slag discharge port is smaller and smaller until the slag discharge port is blocked, the temperature of a bed layer is increased sharply, the reaction bed layer moves upwards, the liquid level of the slag is improved, the black pipe phenomenon of an oxygen evaporation nozzle occurs, and finally, the crushed coal pressurized slag gasifier can only be stopped to dig out the furnace and then is started again. The phenomenon of stopping the furnace due to such problems has been observed in many of the pulverized coal slag gasifiers. The gasification furnace needs more than 20 days from the shutdown for cooling, digging and baking to the next start-up operation, so that frequent shutdown not only affects the service life of refractory bricks in the furnace, but also seriously affects the normal operation of a subsequent system and the production of an enterprise, and causes huge loss to the enterprise.

Through analysis, the reasons for slag adhering and blocking at the slag discharging opening are considered to be the following two main reasons:

(1) due to unreasonable steam-oxygen ratio, a reducing atmosphere is formed in the ash melting area, so that iron oxide in the ash is reduced into elemental iron. According to the similar compatibility principle of solute, simple substance iron is quickly gathered, and because the density of iron is greater than that of ash slag, the iron is easily precipitated to cause slag-iron separation, and the phenomenon that molten slag floats on molten iron is formed. When slag is discharged, because the liquid iron has high viscosity and poor fluidity, the liquid iron can not form a jet state under the existing pressure difference condition, and the molten iron falls in a film mode along the inner wall of the slag discharge short section. Because the lower slag nipple is made of copper and is externally provided with a water jacket for cooling, and the iron solidifying point is higher, the slag containing molten iron is hung on the wall and condensed to cause blockage in the process of flowing through the lower slag nipple during slag discharging.

(2) Because the frequency of slag discharging is not well held, the slag discharging is too frequent or the time of single slag discharging is too long, the amount of molten slag stored in a melting zone is too small, the slag in a slag pool is not completely melted, the pressure difference of the pool is small, and the slag jet flow is formed due to insufficient slag amount and power when the slag is discharged, so that the slag slowly flows down to a slag discharging port along with a slag discharging short section, and the slag is condensed to block the slag discharging port due to too long detention time.

Once plugged with slag, it is almost impossible to burn with the flame in the gasifier. The slag blocked at the slag discharge port is mainly a mixture of iron and slag condensed together, the texture is very hard, the cleaning difficulty is high, the time is long, and the production benefit of an enterprise is seriously influenced.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a pressurized slag gasifier with a plasma torch and a steam oxygen nozzle coupled, which can effectively relieve the situations of slag solidification and wall hanging and greatly reduce the cleaning time of solidified ash.

The technical scheme adopted by the invention for solving the technical problems is as follows: a pressurized slag gasification furnace with a plasma torch and a steam oxygen nozzle coupled is constructed, and a steam nozzle, an oxygen nozzle and a plasma torch are arranged in a slag area at the lower part of the gasification furnace.

In the scheme, the steam nozzle, the oxygen nozzle and the plasma torch are arranged in a ring shape.

In the scheme, the steam nozzle, the oxygen nozzle and the plasma torch deflect at 8-12 degrees from the radial direction.

In the scheme, the plasma torch is connected with the water-cooling protection device.

In the scheme, the furnace wall of the gasification furnace is provided with the water jacket.

The pressurized slag gasifier with the coupled plasma torch and the steam oxygen nozzle has the following beneficial effects:

(1) when the slag is hung on the wall of the gasification furnace, the plasma torch is started, the heat of the plasma torch is utilized to melt the slag hung on the wall, so that the phenomenon that the slag is hung on the wall and blocks a slag discharge port can be effectively relieved, and the shutdown frequency caused by the phenomenon can be reduced;

(2) when the gasifier is shut down for maintenance, because the slag condensed into solid state is extremely difficult to remove, compared with manual furnace digging, the method has the advantages that the solid slag is melted by the high temperature and high heat of the plasma torch, so that the labor and time can be greatly saved;

(3) the invention greatly relieves the problem of blockage of the slag discharge port, reduces the time for blowing out and digging the furnace, increases the production and operation period of enterprises and improves the production benefit of the enterprises.

Drawings

The invention will be further described with reference to the accompanying drawings and examples, in which:

FIG. 1 is a schematic view of a pressurized slag gasifier with a plasma torch and a steam-oxygen nozzle coupled according to the present invention;

fig. 2 is a schematic arrangement of a steam nozzle, an oxygen nozzle and a plasma torch.

Detailed Description

For a more clear understanding of the technical features, objects and effects of the present invention, embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

As shown in FIGS. 1 to 2, a conventional pressure vessel steel material, a furnace lining refractory material, and a water jacket 2 disposed between the outer wall of the furnace and the lining refractory material are used for a furnace body 1 of a pressurized slag gasifier in which a plasma torch and a steam-oxygen nozzle 8 are coupled.

Two plasma torches 4 are arranged in a slag zone of the gasification furnace, the plasma torches 4, the steam nozzles 3 and the oxygen nozzles 8 are arranged in a surrounding mode, and in order to enable a flow field in the gasification furnace to form weak rotational flow, the plasma torches 4, the steam nozzles 3 and the oxygen nozzles 8 are deflected by 10 degrees from the radial direction.

The gasification furnace type is a fixed bed pressurized slag gasification furnace, liquid slag is discharged and non-solid slag is discharged when the gasification furnace normally runs, and a water jacket 2 is arranged on the furnace wall to carry out byproduct steam which can be used as an air source of a steam nozzle 3.

The plasma torch 4 is arranged at the lower part of the pressurized slag gasification furnace and forms a coupling device with a steam and oxygen nozzle 8 of the gasification furnace. Specifically, two plasma torches 4, two steam nozzles 3, and two oxygen nozzles 8 are arranged in a ring shape.

In the invention, the plasma torch 4 arranged at the lower part of the pressurized slag gasification furnace is protected by circulating water cooling.

When the pressurized slag gasifier operates, the gasifier is under high temperature and high pressure linkage protection.

The coal used by the gasification furnace can be long flame coal and anthracite, after the coal enters the gasification furnace through the feed inlet 5 and passes through the stages of drying, dry distillation, gasification and combustion, the organic matter is thermally decomposed and gasified to generate synthetic gas, the synthetic gas flows upwards along the coal in a counter-flow manner and is continuously cooled and discharged from the synthetic gas outlet 6 of the gasification furnace, and the temperature of the synthetic gas at the synthetic gas outlet 6 of the gasification furnace is 300-. The ash content of the coal material is melted into liquid state in a high temperature combustion area (about 1800 ℃) and is discharged through a lower slag discharge port 7, and for the coal with high ash fusion point, a cosolvent is properly added to enhance the fluidity of the slag and properly reduce the ash fusion point. Thermocouples are arranged on different bed layers of the gasifier body, the gasification working condition is determined by monitoring the temperature of the different bed layers in the gasifier, and the gasification reaction temperature is controlled by adjusting the steam-oxygen ratio of the gasification agent.

When the slag wall hanging phenomenon occurs, the plasma torch 4 is operated, the medium gas of the plasma torch 4 is oxygen, the solidified slag is melted by utilizing the high-frequency heat of the plasma torch 4 (the central temperature of the plasma torch is 5000-6000 ℃, and the plasma torch is rich in excited molecules, atoms, free radicals and other active particles), the temperature in the furnace is monitored, the steam-oxygen ratio of the steam nozzle 3 and the oxygen nozzle 8 is adjusted, and after the slag wall hanging problem is solved, the plasma torch 4 is closed, and the normal operation of the gasification furnace is maintained.

When the gasification furnace needs to be shut down for maintenance, the plasma torch 4 is opened, and the solidified slag is melted by using the high temperature of the flame of the plasma torch 4, so that the workload and the time for manually digging the furnace can be greatly reduced.

While the present invention has been described with reference to the embodiments shown in the drawings, the present invention is not limited to the embodiments, which are illustrative and not restrictive, and it will be apparent to those skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope of the invention as defined in the appended claims.

Claims (5)

1. A pressurized slag gasifier with a plasma torch and a steam-oxygen nozzle coupled is characterized in that the steam nozzle, the oxygen nozzle and the plasma torch are arranged in a slag area at the lower part of the gasifier.

2. The plasma torch and steam-oxygen nozzle coupled pressurized slag gasifier as claimed in claim 1, wherein the steam nozzle, oxygen nozzle and plasma torch are arranged in a ring.

3. The plasma torch and the steam-oxygen nozzle coupled pressurized slag gasifier according to claim 1, wherein the steam nozzle, the oxygen nozzle and the plasma torch are all deflected at 8-12 degrees from a radial direction.

4. The pressurized slag gasifier with coupled plasma torch and steam-oxygen nozzle as claimed in claim 1, wherein the plasma torch is connected to a water-cooled protective device.

5. The pressurized slag gasifier with coupled plasma torch and steam-oxygen nozzle as claimed in claim 1, wherein the wall of the gasifier is arranged with a water jacket.

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