A wear-resistant process for waste boiler of gasifier and a syngas cooling system

Abstract

The invention discloses an anti-wear process for a waste boiler of a gasifier and a synthesis gas cooling system. The water-cooled wall is located in a gasifier shell, a slag pool is arranged at the bottom of the gasifier shell, an annular gap is formed between the water-cooled wall and the gasifier shell, a cooling water input pipeline passes through the side wall of the gasifier shell and is connected with a cooling nozzle on the water-cooled wall, a quenching air input pipeline passes through the side wall of the gasifier shell and is connected with a quenching air inlet of the water-cooled wall, a pulverized coal input pipeline passes through the side wall of the gasifier shell and is connected with an inlet of a pulverized coal burner on the water-cooled wall; a quenching ring is arranged at the outlet of the bottom of the water-cooled wall, wherein a quenching ring water inlet pipeline is connected with the inlet of the quenching ring, a slag pool water inlet is arranged on the side of the bottom of the gasifier shell, the system has low operating power consumption and cost, and the wear rate of the waste boiler system after the gasifier is low.

Description

Technical Field

[0001] The invention belongs to the technical field of energy chemical industry and relates to an anti-wear process for a waste boiler of a gasifier and a synthesis gas cooling system. Background Art

[0002] The dry coal powder pressurized gasification waste boiler process has become the main direction of the development of modern coal gasification technology due to its wide adaptability to coal types, high efficiency, low wastewater volume and excellent environmental performance.

[0003] In the dry coal powder pressurized gasification waste boiler process used in domestic industrial applications, such as SHELL coal gasification technology, Prenflo coal gasification technology, Huaneng coal gasification technology, etc., the coal gasification technology represented by SHELL adopts primary gasification. The temperature of the synthesis gas rising from the gasification reaction zone is about 1500℃. The high-temperature synthesis gas completely relies on the synthesis gas extracted from the washing tower after the gasification furnace and the outlet of the fly ash filter as quenching gas circulation to cool down. The quenching gas circulation rate is usually 100%-200%. The device has high power consumption, and the synthesis gas cooler, dust collector, washing tower and other equipment are huge, and the operating costs and device investment are high.

[0004] At present, most of the SHELL gasifiers in China have reached the middle and late stages of their service life. Due to various reasons, the quenching gas volume of the gasifiers has been expanded by nearly half, and some have even doubled. This has resulted in an increase in the flow rate of the solid-containing synthesis gas passing through the waste boiler. However, the wear rate is proportional to the cube of the gas flow rate, so the wear rate of the waste boiler has also increased exponentially, greatly shortening the service life of the equipment.

[0005] Therefore, it is a very meaningful task to develop an anti-wear process and a method for cooling the synthesis gas for the above two situations. Summary of the invention

[0006] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide an anti-wear process for gasifier waste boiler and a synthesis gas cooling system, the operating power consumption and cost of the system are low, and the wear rate of the waste boiler system after the gasifier is low.

[0007] To achieve the above-mentioned purpose, the anti-wear process for the waste boiler of a gasifier and the synthesis gas cooling system of the present invention include a water-cooled wall, a gasifier shell, a cooling water input pipe, a quenching gas input pipeline, a coal powder input pipeline, a quenching ring water inlet pipeline, a washing tower, a liquid separation tank, a quenching gas preheater, a compressor and a quenching gas preheater;

[0008] The water-cooled wall is located in the gasifier shell, a slag pool is provided at the bottom of the gasifier shell, an annular gap is formed between the water-cooled wall and the gasifier shell, a cooling water input pipeline passes through the side wall of the gasifier shell and is connected to the cooling nozzle on the water-cooled wall, a quenching air input pipeline passes through the side wall of the gasifier shell and is connected to the quenching air inlet of the water-cooled wall, and a pulverized coal input pipeline passes through the side wall of the gasifier shell and is connected to the inlet of the pulverized coal burner on the water-cooled wall;

[0009] A quench ring is provided at the outlet of the bottom of the water-cooled wall, wherein a quench ring water inlet pipe is connected to the quench ring inlet, and a slag pool water inlet is provided on the side of the bottom of the gasifier shell;

[0010] The outlet of the washing tower is connected to the chilled air input pipeline through the liquid separator, the heat absorption side of the chilled air preheater, the compressor and the heat release side of the chilled air preheater in sequence;

[0011] The cooling water input pipeline, the quenching air input pipeline and the pulverized coal input pipeline are distributed in sequence from top to bottom.

[0012] The water-cooled wall is a coil structure or a tube-in-tube structure, and the inner wall of the water-cooled wall is coated with a refractory material layer.

[0013] The water-cooled wall is divided into the first straight pipe section, the curved pipe section, the second straight pipe section, the gradually expanding pipe section, the third straight pipe section and the gradually contracting pipe section from top to bottom. Among them, the first straight pipe section is the cooling zone, the second straight pipe section is the cooling zone, and the third straight pipe section is the reaction zone. The cooling water input pipeline and the quenching gas input pipeline are connected to the cooling zone, and the pulverized coal burner is located on the third straight pipe section.

[0014] The number of the pulverized coal burners is 2-6, and the pulverized coal burners are distributed at equal intervals along the circumferential direction, and the material sprayed by each pulverized coal burner is sprayed along the tangential direction or the horizontal direction.

[0015] The cooling water input pipe is arranged horizontally.

[0016] A sewage outlet is provided at the bottom of the slag pool.

[0017] The present invention has the following beneficial effects:

[0018] In the specific operation of the anti-wear process and synthesis gas cooling system for the waste boiler of a gasifier described in the present invention, coal powder and an oxidizing medium are sent into the gasifier through a pulverized coal burner to undergo a gasification reaction to generate high-temperature synthesis gas. During the upward movement of the high-temperature synthesis gas, the low-temperature synthesis gas from the washing tower is separated by a liquid separator and enters the quenching gas preheater to be preheated by the synthesis gas output by the compressor to prevent condensation of water vapor caused by cooling. The high-temperature synthesis gas is then sent into the water-cooled wall through the compressor. The high-temperature synthesis gas continues to ascend after being cooled by the low-temperature quenching gas, and then is cooled for the second time by cooling water to greatly reduce the flow rate of the quenching gas, thereby reducing the total gas volume flowing through the waste boiler of the gasifier, and further reducing the flow rate of the solid-containing gas, thereby greatly reducing the wear rate of the gas on the heat exchange surface of the waste boiler, and the operating power consumption and cost are low, and the structure is simple and the practicability is extremely strong. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of the present invention.

[0020] Among them, 1 is the gasifier shell, 2 is the water-cooled wall, 3 is the slag pool, 4 is the annular gap, 5 is the pulverized coal burner, 6 is the cooling water input pipeline, 7 is the quenching air input pipeline, 8 is the quenching ring, 9 is the quenching ring water inlet pipeline, 10 is the sewage outlet, 11 is the slag outlet, 12 is the slag pool water inlet, 13 is the compressor, 14 is the quenching air preheater, 15 is the gradually expanding pipe section, 16 is the curved pipe section, 17 is the washing tower, and 18 is the liquid separation tank. DETAILED DESCRIPTION

[0021] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0022] refer to Figure 1The anti-wear process for waste boiler of gasifier and the synthesis gas cooling system of the present invention include a water-cooled wall 2, a gasifier shell 1, a cooling water input pipeline 6, a quenching gas input pipeline 7, a pulverized coal input pipeline, a quenching ring water inlet pipeline 9, a washing tower 17, a liquid separator 18, a quenching gas preheater 14, a compressor 13 and a quenching gas preheater 14; the water-cooled wall 2 is located in the gasifier shell 1, a slag pool 3 is provided at the bottom of the gasifier shell 1, an annular gap 4 is formed between the water-cooled wall 2 and the gasifier shell 1, a cooling water input pipeline 6 passes through the side wall of the gasifier shell 1 and is connected to the cooling nozzle on the water-cooled wall 2, and the quenching gas input pipeline 7 passes through the side wall of the gasifier shell 1 and is connected to the water-cooled wall 2. The pulverized coal input pipeline passes through the side wall of the gasifier shell 1 and is connected with the inlet of the pulverized coal burner 5 on the water-cooled wall 2; a quenching ring 8 is provided at the outlet of the bottom of the water-cooled wall 2, wherein the quenching ring water inlet pipeline 9 is connected with the inlet of the quenching ring 8, and a slag pool water inlet 12 is provided on the side of the bottom of the gasifier shell 1; the outlet of the washing tower 17 is connected with the quenching air input pipeline 7 via the liquid separator 18, the heat absorption side of the quenching air preheater 14, the compressor 13 and the heat release side of the quenching air preheater 14 in sequence; the cooling water input pipeline 6, the quenching air input pipeline 7 and the pulverized coal input pipeline are distributed in sequence from top to bottom, and the compressor 13 is a one-stage centrifugal compressor.

[0023] The water-cooled wall 2 is divided into a first straight pipe section, a curved pipe section 16, a second straight pipe section, a gradually expanding pipe section 15, a third straight pipe section and a gradually contracting pipe section from top to bottom, wherein the first straight pipe section is a cooling zone III, the second straight pipe section is a cooling zone II, the third straight pipe section is a reaction zone I, the cooling water input pipeline 6 and the quenching gas input pipeline 7 are connected to the cooling zone II, and the pulverized coal burner 5 is located on the third straight pipe section.

[0024] The water-cooled wall 2 is a coil structure or a tube-in-tube structure, and the inner wall of the water-cooled wall 2 is coated with a refractory material layer; the number of the pulverized coal burners 5 is 2-6, and the pulverized coal burners 5 are evenly spaced along the circumferential direction, and the material sprayed by each pulverized coal burner 5 is sprayed along the tangential or horizontal direction; the cooling water input pipeline 6 is arranged horizontally; and a sewage outlet 10 is provided at the bottom of the slag pool 3.

[0025] The working principle of the present invention is:

[0026] The pulverized coal and the oxidizing medium are sent into the gasifier through the pulverized coal burner 5 for gasification reaction to produce high-temperature synthesis gas. The synthesis gas (1500°C) goes up along the reaction zone I and enters the cooling zone II. At this time, the low-temperature synthesis gas (170°C) directly from the washing tower 17 is separated by the liquid separator 18 and enters the quenching gas preheater 14 to be preheated by the synthesis gas output by the compressor 13 to prevent condensation of water vapor caused by cooling. Then, it is sent to the cooling zone II through the compressor 13. The high-temperature synthesis gas continues to rise after being cooled by the low-temperature quenching gas. Atomized cooling water is sent through the cooling nozzle above the quenching gas inlet to continue to cool the high-temperature synthesis gas for the second time. Then, it enters the duct zone III to greatly reduce the flow rate of the quenching gas, thereby reducing the total gas volume flowing through the waste boiler of the gasifier, thereby reducing the flow rate of the solid-containing gas, and the wear rate of the gas on the heat exchange surface of the waste boiler is greatly reduced.

[0027] The gasifier is a dry-feed pressurized fluidized-flow gasifier with a gasification pressure of 0.6-4.5 MPa and a reaction temperature of 1300°C-1700°C. The gasifier adopts a liquid slag removal method, and the gasifier shell 1 serves as a pressure vessel to withstand the gasification pressure.

[0028] The quenching water is sprayed into the slag pool 3 through the quenching ring 8 to quench the high-temperature liquid slag flowing down the wall of the slag opening 11 , and the quenched slag water is discharged from the bottom of the slag pool 3 through the drain outlet 10 .

[0029] The feed of the pulverized coal burner 5 includes gasification raw materials and oxidants. The gasification raw materials are powders made of coal, coke, semi-coke, petroleum coke and other raw materials. The oxidants are pure oxygen, enriched oxygen, or a mixture of pure oxygen / enriched oxygen and water vapor / carbon dioxide.

[0030] The working medium outputted from the desuperheating water input pipe 6 can be boiler feed water, desalted water, conversion condensate, deoxygenated water or organic wastewater, etc. The working medium enters the desuperheating water in the form of atomization.

Claims

1. A system for anti-wear of waste boiler of gasifier and cooling of synthesis gas, characterized in that: It comprises a water-cooled wall (2), a gasifier shell (1), a cooling water input pipeline (6), a quenching gas input pipeline (7), a pulverized coal input pipeline, a quenching ring water inlet pipeline (9), a washing tower (17), a liquid separation tank (18), a compressor (13) and a quenching gas preheater (14); The water-cooled wall (2) is located in the gasifier shell (1), a slag pool (3) is arranged at the bottom of the gasifier shell (1), an annular gap (4) is formed between the water-cooled wall (2) and the gasifier shell (1), a cooling water input pipeline (6) passes through the side wall of the gasifier shell (1) and is connected to the cooling nozzle on the water-cooled wall (2), a quenching air input pipeline (7) passes through the side wall of the gasifier shell (1) and is connected to the quenching air inlet of the water-cooled wall (2), and a pulverized coal input pipeline passes through the side wall of the gasifier shell (1) and is connected to the inlet of the pulverized coal burner (5) on the water-cooled wall (2); A quenching ring (8) is provided at the outlet of the bottom of the water-cooled wall (2), wherein a quenching ring water inlet pipe (9) is connected to the inlet of the quenching ring (8), and a slag pool water inlet (12) is provided on the side of the bottom of the gasifier shell (1); The outlet of the washing tower (17) is connected to the quenching gas input pipeline (7) via the liquid separation tank (18), the heat absorption side of the quenching gas preheater (14), the compressor (13) and the heat release side of the quenching gas preheater (14) in sequence; The cooling water input pipeline (6), the quenching air input pipeline (7) and the pulverized coal input pipeline are arranged in sequence from top to bottom; The water-cooled wall (2) is a coil structure or a tube-column structure, and the inner wall of the water-cooled wall (2) is coated with a refractory material layer; The water-cooled wall (2) is divided into a first straight pipe section, a curved pipe section (16), a second straight pipe section, a gradually expanding pipe section (15), a third straight pipe section and a gradually contracting pipe section from top to bottom, wherein the first straight pipe section is a cooling zone (III), the second straight pipe section is a cooling zone (II), the third straight pipe section is a reaction zone (I), a cooling water input pipeline (6) and a quenching gas input pipeline (7) are connected to the cooling zone (II), and the pulverized coal burner (5) is located in the third straight pipe section.

2. The system for anti-wear of waste boiler of gasifier and cooling of synthesis gas according to claim 1 is characterized in that: The number of the pulverized coal burners (5) is 2-6, and the pulverized coal burners (5) are distributed at equal intervals in the circumferential direction, and the material sprayed by each pulverized coal burner (5) is sprayed in a tangential or horizontal direction.

3. The system for anti-wear of waste boiler of gasifier and cooling of synthesis gas according to claim 1, characterized in that: The cooling water input pipe (6) is arranged horizontally.

4. The system for anti-wear of waste boiler of gasifier and cooling down synthesis gas according to claim 1, characterized in that: A sewage outlet (10) is provided at the bottom of the slag pool (3).

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