CN106544061B

CN106544061B - High-yield oil slag gasification furnace and coal gasification method

Info

Publication number: CN106544061B
Application number: CN201611051448.1A
Authority: CN
Inventors: 傅敏燕; 丁烙勇
Original assignee: SHANGHAI ZEMAG MINDAC MACHINERY EQUIPMENT CO LTD
Current assignee: Zemak Shanghai Environmental Protection Energy Technology Co ltd
Priority date: 2016-11-25
Filing date: 2016-11-25
Publication date: 2022-04-12
Anticipated expiration: 2036-11-25
Also published as: CN106544061A

Abstract

In order to solve the problems that an entrained flow gasification technology and other coal gasification technologies have no liquid by-products and a fixed bed Lurgi gasifier gasification technology and a slag gasification technology have low oil yield, the invention provides a slag gasification furnace with high oil yield, coal is added into the slag gasification furnace from the top of the slag gasification furnace, and combustion is carried out at the bottom of the slag gasification furnace to form slag and crude coal gas; the tar and oil components, as well as the phenol component, are separated from the raw gas. The invention improves the quality-based comprehensive utilization of coal, fully utilizes the gas-solid countercurrent flow principle of fixed bed coal gasification, firstly pyrolyzes and distills the coal on the upper layer of the coal, extracts light volatile components in the coal to obtain coal tar, coal gas and coke, and gasifies the coke slag to produce the coal gas, thereby realizing the high-efficiency utilization of oil products and light components in the coal in different chemical processes in the same equipment, and obtaining various byproducts with high added values, such as tar, oil, phenol, ammonia, naphtha and the like.

Description

High-yield oil slag gasification furnace and coal gasification method

Technical Field

The invention relates to a coal gasification furnace, in particular to a slag gasification furnace with high oil yield and a coal gasification method with high oil yield.

Background

Coal is used for power generation and heat cooling and is also a main chemical raw material, China is in shortage of petroleum, coal resources are relatively rich, the coal reserves for oil refining are huge in the total reserves of general investigation, if the oil of coal is extracted, not only can artificial petroleum be obtained, but also industrial raw materials with high added value and high-quality fuels can be obtained, but at present, the coal which is actually used for oil refining is few.

In order to further improve the utilization efficiency of coal and the energy utilization efficiency of coal, reduce the consumption of water resources in the coal utilization process and reduce environmental pollution, the modern society pays more and more attention to the graded and graded utilization of coal, and develops a plurality of new technologies, but the new technologies have a certain distance from industrial application and are only limited to a laboratory scale or a technical verification stage. For the modern coal chemical industry of coal for industrial raw material mainly producing synthesis gas by coal gasification, the industrialized pressurized coal gasification technology mainly comprises entrained-flow bed gasification technology (such as dry coal powder gasification, coal water slurry gasification and the like), fixed bed gasification technology (such as lurgi furnace dry bottom moving bed gasification, BGL slag gasification) and the like.

The entrained flow technology is mainly represented by SHELL (Shell) dry coal powder pressurized gasification, GSP (gas gasification process) pulverized coal pressurized gasification and Texaco coal water slurry pressurized gasification, pure oxygen is used as a gasification agent, slag gasification is carried out at high temperature and high pressure, only trace methane exists in crude coal gas, byproducts such as tar, naphthalene, phenol water and the like are not generated, oil and volatile matters contained in the coal are all cracked into simplest small molecules, and therefore no liquid product is produced.

The fixed bed gasification technology is a gasification device for converting blocky solid carbon-containing fuel into crude gas, the crude gas is an indispensable raw material gas in industrial production, and chemical products prepared from effective components of carbon monoxide and hydrogen in the crude gas comprise synthetic oil, urea, methanol, glycol and the like. At present, fixed bed gasification technology is mostly adopted in domestic coal gasification plants as the main coal gasification technology for producing raw material gas, and the fixed bed gasification technology comprises crushed coal pressurized gasification furnace gasification technology (Lurgi furnace), crushed coal pressurized slag gasification technology (BGL furnace) and fixed bed intermittent gasification technology (UGI). The fixed bed technology of Lurgi furnace adopts solid slag discharge, the furnace temperature is low, the coal and gasifying agent flow reversely in the furnace

A combustion zone, a gasification zone and a dry distillation zone (a combustion layer, a gasification layer and a dry distillation layer) are sequentially formed from bottom to top, and a combustion reaction is carried out on the combustion layer to provide heat required by the gasification reaction; carrying out gasification reaction of water vapor and C in a gasification layer; more methane is generated in the methane layer; in the dry distillation layer, mainly volatile components in the coal are released. The obtained crude gas contains a certain amount of impurities such as tar, phenol, ammonia and the like, can be used as a liquid byproduct after separation, and has good economical efficiency.

The fixed bed slag gasification technology combines the advantages of high gasification rate and high gasification strength of the entrained flow slag gasification technology and the advantages of low oxygen consumption and low furnace body structure of the Lurgi furnace fixed bed pressure gasification technology, overcomes the defects of high energy consumption and high investment of the entrained flow slag gasification technology, large amount of wastewater, difficult treatment and high treatment cost of the Lurgi furnace fixed bed pressure gasification technology, and has the comprehensive advantages of less construction investment, short period, high production rate, low operation cost and low maintenance cost. The dry distillation zone of the gasifier produces tar and oil which are entrained in the raw gas. The crude gas is washed and cooled to separate tar and oil, and a certain amount of phenol-containing wastewater with high concentration phenol ammonia is separated. These are high value-added by-products, can be used as raw materials for post-processing, or can be directly sold as by-products, and have good economic benefit. Typical representatives of this technology are the BGL slag gasifier and slag gasification technology. Although the representative fixed bed technology in the market at present is lurgi furnace gasification and slag gasification technology, which is mainly aimed at completing coal gasification and producing partial liquid products, the oil yield is only about 50% of the oil content of aluminum retort analysis, and the rest oil-containing components and volatile components are reacted into small molecules, so the oil yield is still low.

Disclosure of Invention

In order to solve the problems that an entrained flow slag gasification technology and other coal gasification technologies have no liquid by-products and a fixed bed Lurgi gasifier gasification technology and a slag gasification technology are low in oil yield, the invention provides a novel slag gasification furnace with high oil yield and a coal gasification method with high oil yield, so that a higher oil yield is obtained.

The invention provides a high-oil-yield slag gasifier, which comprises a hollow furnace body, wherein the furnace body comprises a combustion area, a gasification area and a dry distillation area from bottom to top.

In a second aspect, the present invention provides a high-yield coal gasification method, including: coal is added into the slag gasifier from the top of the slag gasifier, and is combusted at the middle bottom of the slag gasifier to form slag and raw coal gas; the crude gas escapes from the furnace top and enters a subsequent working section, and tar, oil components and phenol components are separated out.

In a preferred embodiment of the invention, the slag gasifier aspect ratio is preferably at least 2.2, more preferably at least 2.5, such as 2.2-3.5, more preferably 2.2-3.0, more preferably 2.5-2.8. Wherein the height to diameter ratio "high" means "height from the slag bath to the top".

In a preferred embodiment of the invention, the distance from the liquid level of the slag bath to the raw gas outlet is preferably 10m or more, more preferably 12m or more, such as 14m, 15m, 16m, 18m, etc. In a preferred embodiment of the invention, a coolant nozzle is arranged in the gasification zone of the slag gasification furnace and is used for spraying coolant to the gasification zone to cool the gasification zone. Wherein the coolant is preferably water, water vapor, or a combination of both.

In a preferred embodiment of the invention, the temperature of the gasification zone of the slag gasifier is preferably 50-800 ℃ lower than that of the combustion zone, more preferably 100-600 ℃, more preferably 150-500 ℃, more preferably 200-400 ℃, such as 250 ℃ and 300 ℃.

In a preferred embodiment of the invention, the slag gasifier combustion zone temperature is preferably equal to or more than 1500 ℃, more preferably equal to or more than 1800 ℃, more preferably equal to or more than 2000 ℃.

In a preferred embodiment of the present invention, the temperature of the gasification zone is preferably 1000-.

Wherein the number of the nozzles may be an odd number or an even number, and may be at the same height or different heights. In a preferred embodiment, the nozzles are evenly distributed around the inner surface of the furnace body.

The layout of the coolant nozzles is consistent with that of the gasification agent nozzles in the combustion zone, wherein the consistent layout means that at least the number or density, distribution angle and nozzle spacing of the coolant nozzles are consistent with those of the gasification agent nozzles; and a coolant nozzle is arranged above each gasifying agent nozzle.

In a preferred embodiment of the present invention, the coolant nozzle fluid passage includes a tapered section, a throat section, and a diverging section, wherein the fluid passage cross-sectional area of the tapered section gradually decreases from the fluid passage main portion to the throat section, and the fluid passage cross-sectional area of the diverging section gradually increases from the throat section to the extreme end.

Wherein, the included angle between the inner wall of the divergent section and the inner wall of the throat part is preferably 10-30 degrees. In a more preferred embodiment of the present invention, the inner wall of the divergent section of the coolant nozzle is provided with a flow guiding groove, and the flow guiding groove extends from the connection end with the throat part to the tail end of the divergent section. More preferably, the guide grooves are arranged obliquely or spirally. Wherein, the oblique arrangement means that the direction of the diversion trench is not in the diameter direction of the fluid channel.

In a preferred embodiment of the invention, the coal particles preferably have a diameter of 3mm or more, more preferably 4mm or more, more preferably 5mm or more, more preferably 6mm or more. In a more preferred embodiment of the invention, the coal particles preferably have a diameter of 50mm or less, more preferably 40mm or less, more preferably 30mm or less.

In a more preferred embodiment of the invention, the coal particles have a diameter of e.g. 6-50mm, preferably 8-45mm, more preferably 10-40mm, more preferably 15-35mm, more preferably 20-30 mm. In a preferred embodiment of the invention, the pressure in the slag gasifier is preferably 15-50bar, more preferably 20-40bar, more preferably 25-35 bar. In a preferred embodiment of the invention, there is no tar return step; or there is no system for tar return to the furnace.

In a preferred embodiment of the invention, the slag gasifier further comprises a coal lock at the top. Wherein the number of coal locks is preferably two. In a further preferred embodiment of the invention, the coal lock is connected to the furnace body by a Y-shaped transition bin. In a more preferred embodiment of the invention, two coal locks alternately feed coal into the furnace body. The invention improves the quality-based comprehensive utilization of coal, fully utilizes the gas-solid countercurrent flow principle of fixed bed coal gasification, firstly pyrolyzes and distills the coal on the upper layer of the coal, extracts light volatile components in the coal to obtain coal tar, coal gas and coke, and gasifies the coke slag to produce the coal gas, thereby realizing the high-efficiency utilization of oil products and light components in the coal in different chemical processes in the same equipment, and obtaining various byproducts with high added values, such as tar, oil, phenol, ammonia, naphtha and the like.

Drawings

FIG. 1 is a schematic view of a slag gasifier according to an embodiment of the present invention;

FIG. 2 is a schematic diagram showing a comparison of cooling effects of the same (A) and different (B) arrangements of the coolant nozzles and the gasifying agent nozzles according to one embodiment of the present invention;

FIG. 3 is a schematic view of a coolant nozzle fluid passage configuration in accordance with an embodiment of the present invention;

FIG. 4 is a schematic view of an embodiment of a coolant nozzle divergent channel arrangement;

fig. 5 is a schematic diagram showing the cooling effect (a) in the case of the arrangement of the guide grooves of fig. 4 compared with the cooling effect (B) of the conventional nozzle.

Detailed Description

Example 1

Referring to fig. 1, the invention provides a slag gasifier with high oil yield, which comprises a furnace body 1, wherein the bottom of the furnace body is a slag pool 3, and the furnace body comprises a combustion area, a gasification area and a dry distillation area from bottom to top.

The distance from the slag pool of the furnace body to the top coarse coal gas outlet is 14 meters, and the height-diameter ratio of the furnace body is 2.0.

The inventors have found that the smaller the coal particle size, the more uniform the coal particle size, and for this reason, the more likely the coal is to have all of the tar and volatile components precipitated. On the premise of meeting the gasification performance of the gasification furnace, the smaller the size of the coal particles entering the furnace, the more uniform the coal particles are, and the yield of the liquid by-products of the coal can be increased. In this example, coal having a particle size of 6 to 50mm was used.

Coal enters the furnace body 1 from the top coal lock 5 through the Y-shaped transition bin, and a nozzle 2 is arranged in the combustion area and used for spraying gasifying agents such as water vapor and oxygen. The bottom combustion zone temperature is 1800 ℃.

The invention adopts 40bar and 25bar pressure to respectively gasify under the condition of not providing tar return step. The inventors compared the parameter indexes in the case of the tar return step without the tar return step with those in the case of the tar return step, and the results are shown in Table 1.

TABLE 1 Effect of Tar Return to furnace and pressure conditions on oil yield

As can be seen by comparison, the production capacity of the gasification furnace is not greatly influenced under the condition of canceling the step of returning tar to the furnace, but the yield of the tar is greatly increased. By taking the total yield of four liquid-phase byproducts of tar, medium oil, naphtha and crude phenol as a calculation reference, it can be seen that the tar does not return to the furnace under the same pressure, and the yield of the liquid-phase byproducts can be respectively improved by 6.6-7.9%. In addition, the working pressure has the obvious influence on the oil yield, the operation pressure is reduced from 40bar to 25bar under the same flow configuration by taking the ton coal by-product amount of four liquid-phase by-products of tar, medium oil, naphtha and crude phenol as a calculation reference, the liquid-phase by-product yield can be respectively improved by 20.5-18.9%, and particularly the yield of naphtha and crude phenol is obviously improved.

Example 2

The distance from the slag pool of the furnace body to the top coarse coal gas outlet is 16m, and the height-diameter ratio of the furnace body is 2.3. Compared with the existing Lurgi furnace or slag gasifier and the example 1, the residence time and the contact time of the feed coal and the coal gas are longer, and the coal gas fully heats the coal particles and drives out light oil-containing components including coal tar and volatile matters. The coal tar and volatile component content carried by coal particles after dry distillation are reduced, and the yield of crude gas and the tar content in the crude gas are improved, so that the yield of liquid byproducts is improved. Meanwhile, the temperature of the discharged gas is still kept in a reasonable range, and the phenomenon that the crude gas carries too low liquid by-product capacity due to too low temperature is avoided.

The bottom combustion zone temperature was 2000 ℃. Otherwise refer to example 1.

TABLE 2 influence of furnace height on oil yield

As can be seen from Table 2, the yields of the four products of tar, medium oil, naphtha and crude phenol are all improved, and the yield of the liquid-phase by-product can be improved by 0.35% under the scheme of example 2 by taking the total yield of the four liquid-phase by-products of tar, medium oil, naphtha and crude phenol as a calculation reference; this shows that the furnace height in example 2 of the present invention is optimized to obtain higher oil yield. In addition, the inventor also finds that the temperature of the gasification zone is reduced, the carbonization zone length can be changed in phase and prolonged, and the development of the carbonization zone is facilitated. For this purpose, in the gasification zone of the furnace body 1, a coolant nozzle 4 is provided for spraying a coolant such as water or steam into the gasification zone to cool the gasification zone.

A coolant nozzle is arranged in the gasification zone, and the temperature of the gasification zone is reduced to be 300 ℃ lower than that of the combustion zone. The coolant nozzles are arranged in line with the gasification nozzle layout, which means that the nozzle orientation, distance, density, etc. are in line with each other, and one coolant nozzle is arranged above each gasification nozzle, i.e. the gasification nozzle layout is exactly in line with the coolant nozzle layout except for the height. Referring to fig. 2A, under the condition that the layout of the gasification agent nozzles is consistent with that of the cooling agent nozzles, the cooling agent temperature-reducing section and the gasification agent spraying section are kept consistent or close, so that a better temperature-reducing effect is achieved, and if the layout is different, as shown in fig. 2B, a blind area exists between the cooling agent temperature-reducing section 10 (solid line area) and the gasification agent spraying section 11 (dotted line area), so that the temperature-reducing effect is poor.

Referring to fig. 3, the coolant nozzle of the present invention is extended into the inside of the gasification furnace, the fluid pipe includes a tapered section 41, a throat 42 and a diverging section 43, the sectional area of the fluid passage of the tapered section 41 is gradually reduced from the fluid passage portion 44 in the wall of the gasification furnace to the throat 42, the sectional area of the fluid passage of the diverging section 43 is gradually enlarged from the end connected with the throat 42 to the end, and the included angle between the inner wall of the diverging section and the inner wall of the throat may be any angle within the range of 10 ° to 30 °. The tapered section 41 accelerates the fluid in the tapered section due to the reduced cross-sectional area, thereby increasing the throw distance, and the diverging section directs the coolant to spray in a region of greater angle. Referring to fig. 4, the coolant nozzle is provided with the guide grooves 40, the guide grooves 40 may be disposed in an inclined manner (4A) or a spiral manner (4B), and referring to fig. 5, the guide grooves are disposed in such a manner that the coverage area 20 (solid line area) after the coolant is sprayed is larger than the coverage area 21 (dotted line area) after the coolant is sprayed from the conventional nozzle, so that the cooling effect is better.

However, the temperature of the gasification zone should not be too low, and at the same time, the furnace body should not be too high, so as to prevent the crude gas from being too low in temperature, which is not beneficial to dry distillation, and also can reduce the capability of the crude gas carrying oil phase byproducts.

The embodiments of the present invention have been described in detail, but the embodiments are merely examples, and the present invention is not limited to the embodiments described above. Any equivalent modifications and substitutions to those skilled in the art are also within the scope of the present invention. Accordingly, equivalent changes and modifications made without departing from the spirit and scope of the present invention should be covered by the present invention.

Claims

1. A high-oil-yield slag gasification furnace comprises a hollow furnace body, a crude gas outlet at the top of the furnace body and a slag discharge port at the bottom of the furnace body, wherein a drying and dry distillation area, a gasification area and a combustion area are sequentially arranged in the furnace body from top to bottom, coal enters the furnace body from a top coal lock through a Y-shaped transition bin, and the high-oil-yield slag gasification furnace is characterized in that,

the coal is granular coal with the particle size of 6-50 mm;

the height-diameter ratio of the slag gasifier is at least 2.3;

a gasification agent nozzle is arranged in a combustion zone in the furnace body, and the temperature of the combustion zone is higher than 2000 ℃;

a coolant nozzle is arranged in the gasification area in the furnace body,

a coolant nozzle is arranged above each gasification agent nozzle, the layout of the coolant nozzle is consistent with that of the gasification agent nozzle, the cooling section of the coolant is consistent with that of the gasification agent injection section,

the coolant nozzle extends into the gasification furnace and is used for spraying coolant to the gasification area so as to adjust the temperature of the gasification area.

2. The high oil slag gasifier according to claim 1, wherein the number of the coolant nozzles is odd or even, and the coolant nozzles are located at the same cross section of the furnace body and are uniformly distributed around the inner surface of the furnace body.

3. The high-yield slag gasifier according to any one of claims 1-2, wherein the coolant nozzle fluid passage is located in the furnace body and comprises a tapered section, a throat section and a divergent section, wherein the fluid passage sectional area of the tapered section is gradually reduced from the fluid passage main body part to the throat section, and the fluid passage sectional area of the divergent section is gradually enlarged from the throat section to the extreme end.

4. The high oil slag gasifier as claimed in claim 3, wherein a guiding groove is formed on the inner wall of the divergent section of the coolant nozzle, and the guiding groove extends from the throat part to the tail end of the divergent section.

5. The high oil yield slag gasifier according to claim 4, wherein the flow guide grooves are obliquely or spirally arranged.

6. The high yield slag gasifier of claim 1, wherein the distance from the slag level in the slag pool to the raw gas outlet is at least 10 m.

7. The high yield oil slag gasifier of claim 1, wherein there is no tar return system.

8. The high oil production slag gasifier as claimed in claim 1, wherein the gasification zone temperature of the slag gasifier is lower than the combustion zone temperature of 100-600 ℃.

9. A coal gasification method using the high oil-yielding slag gasifier according to any one of claims 1 to 8, characterized in that the pressure in the slag gasifier is 15 to 80 bar.

10. The coal gasification process of claim 9, wherein there is no tar return step.