Method for controlling slag bonding and ash deposition of waste boiler coal gasification device

Abstract

The invention relates to the technical field of coal gasification, in particular to a control method for slagging and ash deposition of a waste boiler coal gasification device, which comprises the following steps: mixing and grinding raw material coal and an A-type additive, and conveying the mixture to a gasification furnace combustion chamber for combustion; the A-type additive comprises at least one of diatomite, second-grade alumina, aluminum oxide and ferric oxide; a B-type additive is added into spray water at the upper part of a waste boiler section of a gasification furnace and is dispersed to the surface of a water cooling wall of the waste boiler along with vaporization of the spray water, so that the ash accumulation trend of the wall surface of the waste boiler is slowed down; the B-type additive comprises at least one of kaolin and activated alumina. By adding the specific additive, the structure of the original gasification device does not need to be improved, and the original flow field structure and the operation stability of the gasification device are not influenced. The specific additive improves the slagging and ash deposition characteristics of the coal and adsorbs alkali metals of the coal type on the basis of not influencing the viscosity-temperature characteristics of the feed coal, so that the applicability of the feed coal can be widened, and particularly, the additive has a relatively high value in the utilization of high-alkali coal in Xinjiang regions.

Description

Technical Field

[0001] The present invention relates to the technical field of coal gasification, and in particular to a method for controlling slagging and ash accumulation in a waste boiler coal gasification device. Background Art

[0002] Coal gasification technology is the leading technology of modern coal chemical industry, which is divided into three categories: fixed bed gasification technology, fluidized bed gasification technology and entrained bed gasification technology. Among them, entrained bed gasification technology is adapted to the large-scale development trend of modern coal chemical industry and has been widely used. The waste boiler coal gasification technology is the industrial transformation hotspot of the recent research and development of entrained bed gasification technology. The waste boiler-quenching type coal gasification technology recovers the waste heat of high-temperature synthesis gas, produces high-pressure steam as a by-product, reduces the unit effective gas energy consumption, adapts to the development requirements of energy conservation and consumption reduction in coal chemical industry, and has been increasingly used.

[0003] In actual applications, waste boiler type coal gasification technology faces the problems of slagging and ash accumulation on the waste boiler wall. In particular, when high-alkali coal is used, it will face more serious slagging and ash accumulation problems, causing the waste boiler steam production to decline and affecting the long-term stable operation of the coal gasification unit. Summary of the invention

[0004] In view of this, the technical problem to be solved by the present invention is to provide a method for controlling slagging and ash accumulation in a waste boiler gasification device, thereby reducing the slagging and ash accumulation tendency on the waste boiler wall without affecting the stability of liquid slag discharge in the gasification device.

[0005] The present invention provides a method for controlling slagging and ash accumulation in a waste boiler coal gasification device, comprising the following steps:

[0006] The raw coal is mixed with the type A additive, ground, and transported to the combustion chamber of the gasifier for combustion;

[0007] The type A additive includes at least one of diatomaceous earth, secondary alumina, aluminum oxide and iron oxide;

[0008] Adding type B additive into the spray water at the top of the waste boiler section of the gasifier, the additive is dispersed to the surface of the water-cooled wall of the waste boiler as the spray water vaporizes, thereby slowing down the tendency of dust accumulation on the waste boiler wall.

[0009] The B-type additive includes at least one of kaolin and activated alumina.

[0010] Preferably, the gasifier is an entrained flow gasifier;

[0011] The entrained flow gasifier comprises: a gasification section; and a waste boiler section fixedly connected to the bottom of the gasification section.

[0012] Preferably, the mass content of type A additive in the raw coal is 5% to 10%.

[0013] Preferably, among the ground particles, the mass fraction of particles with a particle size of 100 to 300 μm is not less than 80%.

[0014] Preferably, before using the type B additive, the method further comprises: grinding the type B additive to a particle size of 0.1 to 150 μm.

[0015] Preferably, the mass ratio of the type B additive to the raw coal is 1 to 5:100.

[0016] Preferably, the amount of the spraying water is 13-17 t / h; the amount of the type B additive is 0.5-2 t / h.

[0017] Preferably, the control method further includes:

[0018] Spraying a nickel-based metal on the inner wall surface of the waste boiler section of the entrained flow gasifier to obtain a nickel-based metal coating;

[0019] Alternatively, nickel-based metal is added to the refractory coating of the water-cooled wall of the entrained flow gasifier.

[0020] Preferably, the nickel-based metal includes NiCr-Cr3C2, Ni 60 B and Cr 19 At least one of Ni9.

[0021] Preferably, the thickness of the nickel-based metal coating is 0.1 to 2 mm;

[0022] The spraying position is the fire surface of the water cooling pipe of the waste boiler section of the gasifier, and the spraying height is 15m downward from the entrance of the upper end of the waste boiler section.

[0023] In the present invention, adding a specific additive does not require improvement of the original gasification device structure, and does not affect the original flow field structure and operation stability of the gasification device. By using a specific additive, the slagging and ash accumulation characteristics of coal are improved and the alkali metal of coal is adsorbed without affecting the viscosity-temperature characteristics of the raw coal, so that the applicability of the raw coal can be broadened, especially for the utilization of high-alkali coal in Xinjiang. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A structural diagram of an entrained flow gasifier provided for one embodiment of the present invention. DETAILED DESCRIPTION

[0025] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] The present invention provides a method for controlling slagging and ash accumulation in a waste boiler coal gasification device, comprising the following steps:

[0027] The raw coal is mixed with the type A additive, ground, and transported to the combustion chamber of the gasifier for combustion;

[0028] The type A additive is selected from at least one of diatomaceous earth, secondary alumina, aluminum oxide and iron oxide;

[0029] Adding type B additive into the spray water at the top of the waste boiler section of the gasifier, the additive is dispersed to the surface of the water-cooled wall of the waste boiler as the spray water vaporizes, thereby slowing down the tendency of dust accumulation on the waste boiler wall.

[0030] The B-type additive is selected from at least one of kaolin and activated alumina.

[0031] The method for controlling slagging and ash accumulation of a waste boiler coal gasification device provided by the present invention is applicable to an entrained flow gasifier. That is, the gasifier is an entrained flow gasifier. The present invention has no special restrictions on the structure of the entrained flow gasifier, and the structure of the entrained flow gasifier well known to those skilled in the art can be adopted.

[0032] Specifically, the entrained flow gasifier comprises:

[0033] Gasification section;

[0034] And a waste boiler section fixedly connected to the bottom of the gasification section.

[0035] Figure 1 This is a structural diagram of an entrained flow gasifier provided by an embodiment of the present invention, wherein 1 is a gasification section, 2 is a waste boiler section, 3 is the connection between the combustion chamber of the gasification section and the waste boiler section, and 4 is the fire surface of the water cooling pipe of the waste boiler section of the gasifier.

[0036] The gasification section 1 is mainly used for gasification reaction of raw coal with oxygen, water vapor, etc. The waste boiler section 2 is mainly used for recovering the high-temperature pyrolysis gas after gasification and the heat in the slag to produce high-pressure steam.

[0037] In certain embodiments of the present invention, the raw coal is anthracite.

[0038] In certain embodiments of the present invention, the type A additive is diatomaceous earth and ferric oxide; or secondary alumina and aluminum oxide, with a mass ratio of 7:3.

[0039] In certain embodiments of the present invention, the mass content of type A additive in the raw coal is 5% to 10%, such as 5%, 7%, or 10%.

[0040] In certain embodiments of the present invention, the grinding is performed in a coal mill. Among the particles after the grinding, the mass fraction of particles with a particle size of 100 to 300 μm is not less than 80%, such as 85%.

[0041] In certain embodiments of the present invention, the pulverized coal is delivered into the combustion chamber of the gasifier via a water-coal slurry pump or a pulverized coal delivery system.

[0042] In the present invention, the B-type additive is added to the spray water at the upper part of the waste boiler section, and dispersed to the surface of the waste boiler water-cooled wall as the spray water vaporizes, thereby slowing down the tendency of dust accumulation on the waste boiler wall;

[0043] The B-type additive is selected from at least one of kaolin and activated alumina.

[0044] In certain embodiments of the present invention, before using the type B additive, the method further includes: grinding the type B additive to a particle size of 0.1 to 150 μm. Then, adding the additive to the spray water storage tank at the top of the waste boiler. The spray water is sprayed at the interface between the gasifier combustion chamber and the waste boiler section.

[0045] In certain embodiments of the present invention, the amount of the spray water is 13-17 t / h, such as 13 t / h, 15 t / h, 17 t / h. The amount of the type B additive is 0.5-2 t / h, such as 0.5 t / h, 1 t / h, 2 t / h.

[0046] In certain embodiments of the present invention, the mass ratio of the type B additive to the raw coal is 1 to 5:100, such as 1:100, 3:100, or 5:100.

[0047] In certain embodiments of the present invention, the specific adding position of the type B additive (i.e., the spraying position of the spray water) is the connection point 3 between the gasifier combustion chamber and the waste boiler section, and the main action position is the slag outlet of the combustion chamber. It does not affect the viscosity-temperature characteristics of the coal ash and has no effect on the liquid slag discharge of the gasifier.

[0048] In some embodiments of the present invention, the control method further comprises:

[0049] Spraying a nickel-based metal on the inner wall surface of the waste boiler section of the entrained flow gasifier to obtain a nickel-based metal coating;

[0050] or

[0051] A nickel-based metal is added to the water-cooled wall refractory coating of the entrained flow gasifier.

[0052] Thereby slowing down the trend of slag accumulation.

[0053] Regarding the technical solution of spraying nickel-based metal on the inner wall surface of the waste pot section of the entrained flow gasifier:

[0054] The nickel-based metal is selected from NiCr-Cr3C2, Ni 60 B and Cr 19 At least one of Ni9. The thickness of the nickel-based metal coating is 0.1-2 mm, such as 0.1-0.5 mm. The spraying position is the fire surface 4 of the water cooling pipe of the waste boiler section of the gasifier, and the spraying height is 15 m downward from the entrance of the upper end of the waste boiler section.

[0055] Regarding the technical solution of adding nickel-based metal to the water-cooled wall refractory coating of the entrained flow gasifier:

[0056] The nickel-based metal is selected from NiCr-Cr3C2, Ni 60 B and Cr 19 At least one of Ni9. In the water-cooled wall refractory coating, the amount of nickel-based metal added is 0.1wt% to 0.5wt%.

[0057] In order to further illustrate the present invention, a method for controlling slagging and ash accumulation in a waste boiler coal gasification device provided by the present invention is described in detail below in conjunction with embodiments, but it should not be construed as limiting the scope of protection of the present invention.

[0058] Example 1

[0059] Use Figure 1 The entrained flow gasifier shown is used to control slagging and ash accumulation in the waste boiler coal gasification device:

[0060] The raw coal (anthracite) used is a mixture of Suhuanggou coal and Beishan coal;

[0061] The type A additive is diatomaceous earth; the mass content of the type A additive in the raw coal is 5%;

[0062] The type B additive is kaolin; the mass ratio of the type B additive to the raw coal is 1:100;

[0063] The raw coal is mixed with the type A additive, ground in a coal mill (the mass fraction of particles with a particle size of 100 to 300 μm is 85% of the ground particles), and then transported to the combustion chamber of the gasifier through a water-coal slurry pump for combustion;

[0064] The type B additive is ground to a particle size of 0.1 to 150 μm, added to the spray water storage tank at the top of the waste boiler of the gasifier, and dispersed to the surface of the water-cooled wall of the waste boiler as the spray water vaporizes, thereby slowing down the ash accumulation trend on the waste boiler wall; the specific adding position of the type B additive (i.e., the spray water spraying position) is the connection point 3 between the combustion chamber of the gasifier and the waste boiler section, and the main action position is the slag outlet of the combustion chamber, which does not affect the viscosity-temperature characteristics of the coal ash and has no effect on the liquid slag discharge of the gasifier;

[0065] The amount of spray water is 13t / h; the amount of type B additive is 0.5t / h;

[0066] Spraying a nickel-based metal on the inner wall surface of the waste boiler section of the entrained flow gasifier to obtain a nickel-based metal coating;

[0067] The nickel-based metal is NiCr-Cr3C2;

[0068] The thickness of the nickel-based metal coating is 0.1 to 0.5 mm;

[0069] The spraying position is 4 points of the water cooling pipe of the waste boiler section of the gasifier facing the fire surface, and the spraying height is 15m downward from the entrance of the upper end of the waste boiler section.

[0070] Example 2

[0071] Use Figure 1 The entrained flow gasifier shown is used to control slagging and ash accumulation in the waste boiler coal gasification device:

[0072] The raw coal (anthracite) used is a mixture of Suhuanggou coal and Beishan coal;

[0073] The type A additive is secondary alumina and aluminum oxide, with a mass ratio of 7:3; the mass content of the type A additive in the raw coal is 7%;

[0074] The type B additive is kaolin; the mass ratio of the type B additive to the raw coal is 3:100;

[0075] The raw coal is mixed with the type A additive, ground in a coal mill (the mass fraction of particles with a particle size of 100 to 300 μm is 85% of the ground particles), and then transported to the combustion chamber of the gasifier through a water-coal slurry pump for combustion;

[0076] The type B additive is ground to a particle size of 0.1 to 150 μm, added to the spray water storage tank at the top of the waste boiler, and dispersed to the surface of the water-cooled wall of the waste boiler as the spray water vaporizes, thereby slowing down the ash accumulation trend on the waste boiler wall; the specific adding position of the type B additive (i.e., the spray water spraying position) is the connection point 3 between the combustion chamber of the gasifier and the waste boiler section, and the main action position is the slag outlet of the combustion chamber, which does not affect the viscosity-temperature characteristics of the coal ash and has no effect on the liquid slag discharge of the gasifier;

[0077] The amount of spray water is 15t / h; the amount of type B additive is 1t / h;

[0078] Spraying a nickel-based metal on the inner wall surface of the waste boiler section of the entrained flow gasifier to obtain a nickel-based metal coating;

[0079] The nickel-based metal is Ni 60 B;

[0080] The thickness of the nickel-based metal coating is 0.1 to 0.5 mm;

[0081] The spraying position is 4 points of the water cooling pipe of the waste boiler section of the gasifier facing the fire surface, and the spraying height is 15m downward from the entrance of the upper end of the waste boiler section.

[0082] Example 3

[0083] Use Figure 1 The entrained flow gasifier shown is used to control slagging and ash accumulation in the waste boiler coal gasification device:

[0084] The raw coal (anthracite) used is a mixture of Suhuanggou coal and Beishan coal;

[0085] The type A additive is ferric oxide; the mass content of the type A additive in the raw coal is 10%;

[0086] The type B additive is activated alumina; the mass ratio of the type B additive to the raw coal is 5:100;

[0087] The raw coal is mixed with the type A additive, ground in a coal mill (the mass fraction of particles with a particle size of 100 to 300 μm is 85% of the ground particles), and then transported to the combustion chamber of the gasifier through a water-coal slurry pump for combustion;

[0088] The type B additive is ground to a particle size of 0.1 to 150 μm, added to the spray water storage tank at the top of the waste boiler, and dispersed to the surface of the water-cooled wall of the waste boiler as the spray water vaporizes, thereby slowing down the ash accumulation trend on the waste boiler wall; the specific adding position of the type B additive (i.e., the spray water spraying position) is the connection point 3 between the combustion chamber of the gasifier and the waste boiler section, and the main action position is the slag outlet of the combustion chamber, which does not affect the viscosity-temperature characteristics of the coal ash and has no effect on the liquid slag discharge of the gasifier;

[0089] The amount of spray water is 17t / h; the amount of type B additive is 2t / h;

[0090] Spraying a nickel-based metal on the inner wall surface of the waste boiler section of the entrained flow gasifier to obtain a nickel-based metal coating;

[0091] The nickel-based metal is Cr 19 Ni9;

[0092] The thickness of the nickel-based metal coating is 0.1 to 0.5 mm;

[0093] The spraying position is 4 points of the water cooling pipe of the waste boiler section of the gasifier facing the fire surface, and the spraying height is 15m downward from the entrance of the upper end of the waste boiler section.

[0094] Comparative Example 1

[0095] Use Figure 1The entrained flow gasifier shown is different from that of Example 1 in that:

[0096] No type A additives were added to the raw coal;

[0097] No Type B additive was added to the spray water storage tank.

[0098] Comparative Example 2

[0099] Use Figure 1 The entrained flow gasifier shown is different from that of Example 1 in that:

[0100] No type A additive is added to the raw coal.

[0101] Comparative Example 3

[0102] Use Figure 1 The entrained flow gasifier shown is different from that of Example 1 in that:

[0103] No Type B additive was added to the spray water storage tank.

[0104] Comparative Example 4

[0105] Use Figure 1 The entrained flow gasifier shown is different from that of Example 1 in that:

[0106] No type A additives were added to the raw coal;

[0107] No type B additive was added to the spray water storage tank;

[0108] The inner wall surface of the waste pot section of the entrained flow gasifier is not sprayed with nickel-based metal powder.

[0109] The operation conditions of Examples 1 to 3 and Comparative Examples 1 to 4 were compared, and the results are shown in Table 1.

[0110] Table 1 Operation of Examples 1 to 3 and Comparative Examples 1 to 4

[0111]

[0112]

[0113] The description of the above embodiments is only used to help understand the method of the present invention and its core idea. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features disclosed herein.

Claims

1. A method for controlling slagging and ash accumulation in a waste boiler coal gasification device, comprising the following steps: The raw coal is mixed with the type A additive, ground, and transported to the combustion chamber of the gasifier for combustion; The type A additive includes at least one of diatomaceous earth, secondary alumina, aluminum oxide and iron oxide; Adding type B additive into the spray water at the top of the waste boiler section of the gasifier, the additive is dispersed to the surface of the water-cooled wall of the waste boiler as the spray water vaporizes, thereby slowing down the tendency of dust accumulation on the waste boiler wall. The B-type additive includes at least one of kaolin and activated alumina.

2. The control method according to claim 1, characterized in that: The gasifier is an entrained flow gasifier; The entrained flow gasifier comprises: a gasification section; and a waste boiler section fixedly connected to the bottom of the gasification section.

3. The control method according to claim 1, characterized in that: In the raw coal, the mass content of type A additive is 5% to 10%.

4. The control method according to claim 1, characterized in that: Among the ground particles, the mass fraction of particles with a particle size of 100 to 300 μm is not less than 80%.

5. The control method according to claim 1, characterized in that: Before using the type B additive, the method further comprises: grinding the type B additive to a particle size of 0.1 to 150 μm.

6. The control method according to claim 1, characterized in that: The mass ratio of the B-type additive to the raw coal is 1 to 5:

100.

7. The control method according to claim 1, characterized in that: The amount of the spraying water is 13-17 t / h; the amount of the type B additive is 0.5-2 t / h.

8. The control method according to claim 1, characterized in that: The control method further comprises: Spraying a nickel-based metal on the inner wall surface of the waste boiler section of the entrained flow gasifier to obtain a nickel-based metal coating; Alternatively, nickel-based metal is added to the refractory coating of the water-cooled wall of the entrained flow gasifier.

9. The control method according to claim 8, characterized in that: The nickel-based metal includes NiCr-Cr3C2, Ni 60 B and Cr 19 At least one of Ni9.

10. The control method according to claim 8, characterized in that: The thickness of the nickel-based metal coating is 0.1 to 2 mm; The spraying position is the fire surface of the water cooling pipe of the waste boiler section of the gasifier, and the spraying height is 15m downward from the entrance of the upper end of the waste boiler section.

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