A highly efficient spiral reactor for gasification of high-ash coal

Abstract

The present invention relates to an efficient high-ash coal gasification spiral reactor, comprising an ash collector, a feed pipe is provided on the upper part of the ash collector, a high-ash coal inlet and an active substance inlet are provided on the feed pipe, and a high-temperature and high-pressure water inlet is also provided on the feed pipe; a spiral reaction groove is provided in the ash collector, the upper end of the spiral reaction groove is docked with the discharge port of the feed pipe, the lower end of the spiral reaction groove extends out of the ash collector or is connected with the outlet on the ash collector, and the spiral reaction groove is a spiral slideway structure with an arc-shaped cross section and a horizontally opened notch; and a slag discharge port is provided at the lower end of the ash collector. High-ash coal enters the feed pipe, and is modified by the active substance to improve the activity of the high-ash coal. Semi-coke with a high ash content is thrown out by centrifugal force into the ash collector and falls, and is discharged from the slag discharge port, thereby avoiding a large amount of ash from being heated, reducing the amount of high-temperature ash, not only improving the thermal efficiency, but also reducing the load of the ash cooling equipment, making it easier to cool.

Description

Technical Field

[0001] The invention relates to the field of high-ash coal gasification, and in particular to an efficient high-ash coal gasification spiral reactor. Background Art

[0002] The production of hydrogen by gasification of high-ash coal is an effective means of efficiently utilizing high-ash coal. High-ash coal refers to high-ash coal with an ash content greater than 40% and a moisture content of no more than 20% on an air-dried basis, especially bituminous coal and anthracite. At present, from a global perspective, high-ash coal fluidized bed gasification technology has not yet been widely promoted and applied. my country's fluidized bed gasification technology is at the forefront of the world and is in the "trial operation" stage. China has successively established 0.6MPa and 1.0MPa pressurized gasification demonstration devices, of which the 1.0MPa device is currently the world's highest pressure fluidized bed gasifier. From the operating situation, the atmospheric pressure / pressurized fluidized bed gasifier can "digest" high-ash coal with an ash content of 30-40% and produce coal gas rich in CO and H2.

[0003] However, the following problems exist: (1) The coal processing capacity (gasification intensity) per unit time of the gasifier is significantly lower, only 60-80% of the design value; (2) At the designed residence time, the carbon conversion rate is low, about 75-86%. (3) A large amount of ash is heated to above 1000°C in the furnace and then discharged from the gasifier. Not only is the thermal efficiency of the gasifier low, but a large amount of coal (combustion heat) is wasted, resulting in low gasification efficiency. (4) The high-ash coal gasification ash has the characteristics of high temperature and large ash volume. Under normal pressure conditions, spiral slag coolers or air step-by-step cooling are often used, resulting in large equipment, large equipment footprint, very unsatisfactory cooling effect, and high energy consumption. Among them, problems (1) and (2) both indicate that high-ash coal in the fluidized bed has low activity, low gasification rate, and requires a long residence time in the furnace. Problem (3) shows that the ash content of high-ash coal takes away a lot of heat in vain, and the gasification thermal efficiency is low. Problem (4) shows that it is difficult to achieve efficient cooling of a large amount of high-temperature ash. These problems have severely restricted the large-scale promotion and safe and stable operation of high-ash coal fluidized bed gasification technology, not to mention full-load operation and economical operation.

[0004] Therefore, in order to address the problems of low gasification activity of high-ash coal, low gasification thermal efficiency and difficulty in cooling high-temperature and large ash volumes, it is worth studying the development of a reaction device with high gasification rate, high thermal efficiency and easy slag cooling. Summary of the invention

[0005] The purpose of the present invention is to provide an efficient high-ash coal gasification spiral reactor to solve the problems of low high-ash coal gasification activity, low gasification thermal efficiency and difficulty in cooling high-temperature and large ash content in the prior art.

[0006] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: an efficient high-ash coal gasification spiral reactor, comprising an ash collector, a feed pipe connected to the ash collector is arranged on the upper part of the ash collector, a high-ash coal inlet and an active substance inlet for improving the activity of the high-ash coal are arranged on the feed pipe, and a high-temperature and high-pressure water inlet is also arranged on the feed pipe; a spiral reaction groove is arranged in the ash collector, the upper end of the spiral reaction groove is connected to the discharge port of the feed pipe, the lower end of the spiral reaction groove extends out of the ash collector or is connected to the outlet on the ash collector, the spiral reaction groove is a spiral slide structure with an arc-shaped cross-section and a horizontally opened groove; the lower end of the ash collector has a slag discharge port.

[0007] The active substance inlet includes at least one of a modifier inlet and a high-temperature and high-pressure oxygen inlet.

[0008] The active substance inlet includes a modifier inlet, and the modifier is a mixture of 1,8-diazabicycloundec-7-ene, K2S2O8, and diethyl ether, wherein the mass fraction of 1,8-diazabicycloundec-7-ene is 1-19%, the mass fraction of K2S2O8 is 20-47%, and the rest is diethyl ether.

[0009] The active substance inlet includes a high-temperature and high-pressure oxygen inlet, the volume fraction of the introduced oxygen is not higher than 12%, and nitrogen or carbon dioxide is used as the balance gas.

[0010] The active substance inlet includes a modifier inlet and a high-temperature and high-pressure oxygen inlet, and the modifier inlet and the high-temperature and high-pressure oxygen inlet are arranged in sequence up and down, the angle between the modifier inlet direction and the vertical direction is 60°, the angle between the high-temperature and high-pressure oxygen inlet direction and the vertical direction is 45°, and the diameter of the high-pressure oxygen inlet is not greater than the diameter of the modifier inlet.

[0011] The feed pipe is an L-shaped pipe, which includes a vertical section and a horizontal section. The modifier inlet and the high-temperature and high-pressure oxygen inlet are arranged on the vertical section. The end of the horizontal section extends into the ash collector and docks with the upper end of the spiral reaction tank. The high-temperature and high-pressure water inlet is arranged on the vertical section and is arranged opposite to the horizontal section. The diameter of the high-temperature and high-pressure water inlet is not greater than 1 / 5 of the sum of the diameters of the modifier inlet and the high-temperature and high-pressure oxygen inlet.

[0012] The flow rate of the high-temperature and high-pressure water is not less than 6 cm / s.

[0013] An electric heating wire or an electric heating belt is arranged on the outside of the feed pipe, and a temperature sensor is arranged on the feed pipe between the modifier inlet and the high-temperature and high-pressure oxygen inlet.

[0014] An air inlet pipe connected to the ash collector is arranged at the lower end of the ash collector, and a conical distribution plate is arranged on the lower inner wall of the ash collector above the air inlet pipe. The distribution plate and the inner wall of the ash collector below form an air chamber, and a plurality of air holes are arranged on the distribution plate.

[0015] The beneficial effects of the present invention are as follows: high-ash coal enters the feed pipe, is modified by active substances to improve the activity of the high-ash coal, forms high-activity semi-coke, improves the gasification rate, and the high-activity semi-coke is brought into the spiral reaction tank by high-temperature and high-pressure water for gasification reaction. The semi-coke with a high ash content is thrown out by centrifugal force into the ash collector and falls, and is discharged from the slag discharge port, thereby avoiding a large amount of ash from being heated, reducing the amount of high-temperature ash, not only improving thermal efficiency, but also reducing the load of the ash cooling equipment, making it easier to cool. Since the semi-coke with a high ash content is discharged in time, the effective volume of the spiral reaction tank is fully utilized, the gasification time of the semi-coke is greatly extended, the gasification is relatively sufficient, and the ash content in the gasified mixed gas is small, that is, the amount of dust is small, which is beneficial to the subsequent purification of the mixed gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of a first embodiment of an efficient high-ash coal gasification spiral reactor of the present invention;

[0017] Figure 2 yes Figure 1 Schematic diagram of the installation structure of the horizontal section of the middle feed pipe and the ash collector;

[0018] Figure 3 yes Figure 1 The structural diagram of the middle feed pipe;

[0019] Figure 4 It is a structural schematic diagram of a feed pipe in Example 2 of an efficient high-ash coal gasification spiral reactor of the present invention;

[0020] Figure 5 It is a schematic structural diagram of an ash collector in Example 3 of an efficient high-ash coal gasification spiral reactor of the present invention. DETAILED DESCRIPTION

[0021] An embodiment of an efficient high-ash coal gasification spiral reactor of the present invention is as follows: Figure 1-Figure 3As shown, it includes an ash collector 1, and a feed pipe 3 connected to the ash collector 1 is arranged on the upper part of the ash collector 1, and a high-ash coal inlet 6 and an active material inlet for improving the activity of the high-ash coal are arranged on the feed pipe 3. The active material inlet includes a modifier inlet 7 and a high-temperature and high-pressure oxygen inlet 8, and the modifier inlet and the high-temperature and high-pressure oxygen inlet are arranged in sequence up and down. The modifier inlet 7 and the high-temperature and high-pressure oxygen inlet 8 both adopt a circular tube structure. The angle between the modifier inlet direction and the vertical direction is 60°, the angle between the high-temperature and high-pressure oxygen inlet direction and the vertical direction is 45°, and the diameter of the high-pressure oxygen inlet is not greater than the diameter of the modifier inlet. The modifier adopts a mixture of 1,8-diazabicycloundec-7-ene, K2S2O8, and ether, wherein the mass fraction of 1,8-diazabicycloundec-7-ene is 1-19%, the mass fraction of K2S2O8 is 20-47%, and the rest is ether. High temperature and high pressure oxygen uses low concentration oxygen, the volume fraction of oxygen is not higher than 12%, and nitrogen or carbon dioxide is used as the balance gas.

[0022] The feed pipe 3 is also provided with a high-temperature and high-pressure water inlet 9. A spiral reaction tank 2 is provided in the ash collector 1, and the upper end of the spiral reaction tank 2 is butted with the discharge port of the feed pipe, and the lower end of the spiral reaction tank extends out of the ash collector. The spiral reaction tank 2 is a spiral slideway structure with an arc-shaped cross section and a horizontally opened notch. The notch is opened horizontally, that is, the notch is horizontally radially outwardly facing the inner wall of the ash collector. The slope of the spiral reaction tank (the angle between each layer and the horizontal plane) is not greater than 50°. In this embodiment, the spiral reaction tank is a semicircular structure in cross section. The lower end of the ash collector has a slag discharge port 10. The feed pipe 3 is an L-shaped tube, and the feed pipe 3 includes a vertical section 4 and a horizontal section 5. The modifier inlet 7 and the high-temperature and high-pressure oxygen inlet 8 are arranged on the vertical section 4, and the end of the horizontal section extends into the ash collector and butts with the upper end of the spiral reaction tank. The high temperature and high pressure water inlet 9 is arranged on the vertical section and opposite to the horizontal section, and the diameter of the high temperature and high pressure water inlet is not greater than 1 / 5 of the sum of the diameters of the modifier inlet and the high temperature and high pressure oxygen inlet. The flow rate of the high temperature and high pressure water is not less than 6 cm / s.

[0023] The horizontal section of the feed pipe has the following characteristics: the distance h1 between the center line of the horizontal section and the upper end surface of the ash collector is 20 to 50 cm. The horizontal section of the feed pipe is eccentrically arranged relative to the ash collector, the shorter distance h2 between the center line of the horizontal section and two sections of the ash collector parallel to the horizontal section is not greater than 1 / 4 of the diameter of the ash collector, and the longer distance h3 between the end of the horizontal section and two sections of the ash collector perpendicular to the horizontal section is not greater than 3 / 4 of the diameter of the ash collector.

[0024] An electric heating wire 11 or electric heating belt is arranged outside the feed pipe 3, and a temperature sensor is arranged between the modifier inlet and the high-temperature and high-pressure oxygen inlet on the feed pipe. The temperature in the feed pipe is determined according to the CO2 reaction activity of the high-ash coal. When the CO2 reaction activity is greater than 80%, the temperature is not higher than 500°C, otherwise, the temperature should be greater than 500°C. According to the temperature measured by the temperature sensor, an electric heating wire or electric heating belt can be used to supplement heat. The temperature of the high-temperature and high-pressure water is not lower than 500°C, and the pressure is not lower than the corresponding saturated vapor pressure of water.

[0025] The process flow of the high-ash coal gasification spiral reactor of the present invention is as follows: the high-ash coal enters the L-shaped feed pipe through the high-ash coal inlet, and reacts with the modifier and high-temperature and high-pressure oxygen in the vertical section of the feed pipe to generate semi-coke of a special form. When the temperature required for the reaction is relatively high, the heat required for the reaction can be provided by the electric heating wire to maintain the reaction temperature. Through modification and oxidation reactions, a large number of micropores are formed on the semi-angle surface, forming a richer pore structure, and more carbon surface active sites are exposed; it also promotes the generation of highly active groups on the semi-coke surface, so that the gasification reactivity of the generated semi-coke is greatly improved, and it has high activity.

[0026] The generated semi-coke then enters the horizontal section of the feed pipe and the spiral reaction tank in turn, exchanges heat with the high-temperature water from the high-temperature and high-pressure water inlet and reacts, mainly undergoing the following reactions to generate a hydrogen-rich mixed gas. Since the high-ash coal is activated in the feed pipe and has a high activity, it provides good conditions for the gasification reaction ((1)-(4)), making full use of the significant synergistic effect of the oxidation reaction and the gasification reaction.

[0027] CO2 reduction reaction C+ CO2=2CO+162.4kJ / mol (1)

[0028] Water vapor decomposition reaction C+H2O=CO+H2 +131.5kJ / mol (2)

[0029] Water vapor decomposition reaction C+2H2O=CO2+2H2 +90.0kJ / mol (3)

[0030] CO shift reaction CO+H2O=CO2+H2 -41.5kJ / mol (4)

[0031] While the semi-coke is gasifying in the spiral reaction tank, the semi-coke with relatively high ash content is thrown out of the gasification reactor by centrifugal force, flies to the wall of the ash collector, and finally falls along the wall to the bottom of the ash collector and is discharged through the slag discharge port. Due to the timely discharge of the high-ash semi-coke, the effective volume of the spiral reaction tank is fully utilized, the gasification time of the semi-coke is greatly extended, the gasification is more complete, and the ash content in the gasified mixed gas is small, that is, the dust amount is small, which is conducive to the subsequent purification of the mixed gas.

[0032] The beneficial effects of the present invention are as follows: the present invention takes into account the current situation of low gasification activity of high-ash coal, low gasification thermal efficiency and difficulty in cooling high-temperature and large ash content, activates high-ash coal during the feeding process, changes its surface pore structure and chemical structure, greatly increases its activity, and provides favorable conditions for hydrogen production. At the same time, a spiral reaction tank is used to automatically screen and remove coal (semi-coke) with relatively high ash content during the gasification process, greatly increasing the effective space of the reactor, reducing the volume of the reactor, and at the same time increasing the gasification time of coal (semi-coke) with relatively low ash content, making its gasification more complete.

[0033] (1) The modification of the modifier and the oxidation of oxygen in the feed pipe greatly improve the reactivity of high-ash coal, thereby increasing the gasification rate of high-ash coal. This is mainly because the modification and oxidation reaction of the modifier change the surface physical and chemical structure of the semi-coke, and have a significant synergistic effect with the water vapor gasification reaction. The modification and oxidation reaction of the modifier enrich the surface structure of the carbon particles, forming a large number of micropores, and more carbon surface active sites are exposed; the oxidation reaction also promotes the generation of highly active groups in the semi-coke. Therefore, the gasification reactivity of high-ash coal is greatly improved.

[0034] (2) In the spiral reaction tank, coal (semi-coke) with relatively high ash content can be automatically thrown out of the gasification reactor by centrifugal force to prevent it from idling in the reactor and occupying the effective volume of the reactor. At the same time, the gasification time of coal (semi-coke) with relatively low ash content is increased, making it gasified more completely. At the same time, the higher the ash content, the earlier it will be thrown out of the gasification reactor, greatly improving the thermal efficiency of gasification.

[0035] (3) The device reduces the amount of high-temperature ash, which not only improves thermal efficiency, but also greatly reduces the amount of high-temperature ash, reduces the load of ash cooling equipment, and avoids the problem of high-temperature cooling of large ash volumes. The problem of high-temperature cooling of large ash volumes in the existing technology is still one of the problems that need to be solved urgently in high-ash coal gasification. High-ash coal gasification ash has the characteristics of high temperature and large ash volume. The existing technology mostly uses spiral slag coolers or air step-by-step cooling, which has the problems of bulky equipment, large device footprint, poor cooling effect, and high energy consumption.

[0036] (4) The device avoids the back-mixing of coal (semi-coke) with relatively high ash content, and is close to plug flow. At the same time, the coal (semi-coke) with relatively high ash content is discharged from the spiral reaction tank during the reaction process. Therefore, the effective space of the reactor is fully utilized, and a smaller reactor has a higher processing capacity.

[0037] (5) The device has high thermal efficiency, saves a lot of coal, has small equipment, low investment and good economic benefits. At the same time, the amount of high-temperature ash is small and easy to cool, which reduces the fly ash and dust pollution in the cooling process, and is energy-saving and environmentally friendly.

[0038] (6) The device provides a feasible way to achieve efficient and clean hydrogen production from high-ash coal, and provides an effective way to solve the problems of accumulation, idleness and pollution of a large amount of idle high-ash coal, turning waste into treasure, while achieving energy conservation and environmental protection, killing two birds with one stone.

[0039] Embodiment 2 of the present invention is a highly efficient spiral reactor for gasification of high-ash coal, as shown in FIG. Figure 4 As shown, the only difference from the first embodiment is that only a modifier inlet is provided on the feed pipe, and no high-temperature and high-pressure oxygen inlet is provided, and electric heating wires 12 are provided on both the vertical section and the horizontal section of the feed pipe.

[0040] Embodiment 3 of the present invention is a highly efficient spiral reactor for high-ash coal gasification, as shown in FIG. Figure 5 As shown, the only difference from the first embodiment is that an air inlet pipe 13 connected to the ash collector is provided at the lower end of the ash collector, and a conical distribution plate 14 is provided on the lower inner wall of the ash collector above the air inlet pipe. The distribution plate and the inner wall of the ash collector below form an air chamber 15, and the distribution plate 14 is provided with a plurality of air holes 16. The combination of the distribution plate and the air chamber facilitates the use of gas to loosen the ash. The distribution plate adopts a conical distribution plate, which is made of wear-resistant, high-temperature and high-pressure resistant materials, and the distribution plate cone angle is between 40-150°C.

[0041] In other embodiments of the present invention, the feed pipe may be provided with only a high-temperature and high-pressure oxygen inlet without a modifier inlet; when the use requirements are met, the feed pipe may not be provided with an electric heating wire or an electric heating belt.

Claims

1. An efficient high-ash coal gasification spiral reactor, characterized by: It includes an ash collector, a feed pipe connected to the ash collector is arranged on the upper part of the ash collector, a high-ash coal inlet and an active material inlet for improving the activity of the high-ash coal are arranged on the feed pipe, and a high-temperature and high-pressure water inlet is also arranged on the feed pipe; a spiral reaction groove is arranged in the ash collector, the upper end of the spiral reaction groove is connected to the discharge port of the feed pipe, the lower end of the spiral reaction groove extends out of the ash collector or is connected to the outlet on the ash collector, and the spiral reaction groove is a spiral slide structure with an arc-shaped cross section and a horizontally opened groove; the lower end of the ash collector is provided with a slag discharge port.

2. The efficient high-ash coal gasification spiral reactor according to claim 1 is characterized by: The active substance inlet includes at least one of a modifier inlet and a high-temperature and high-pressure oxygen inlet.

3. The efficient high-ash coal gasification spiral reactor according to claim 2 is characterized by: The active substance inlet includes a modifier inlet, and the modifier is a mixture of 1,8-diazabicycloundec-7-ene, K2S2O8, and diethyl ether, wherein the mass fraction of 1,8-diazabicycloundec-7-ene is 1-19%, the mass fraction of K2S2O8 is 20-47%, and the rest is diethyl ether.

4. The efficient high-ash coal gasification spiral reactor according to claim 2 is characterized by: The active substance inlet includes a high-temperature and high-pressure oxygen inlet, the volume fraction of the introduced oxygen is not higher than 12%, and nitrogen or carbon dioxide is used as the balance gas.

5. The efficient high-ash coal gasification spiral reactor according to claim 2, characterized in that: The active substance inlet includes a modifier inlet and a high-temperature and high-pressure oxygen inlet, and the modifier inlet and the high-temperature and high-pressure oxygen inlet are arranged in sequence up and down, the angle between the modifier inlet direction and the vertical direction is 60°, the angle between the high-temperature and high-pressure oxygen inlet direction and the vertical direction is 45°, and the diameter of the high-pressure oxygen inlet is not greater than the diameter of the modifier inlet.

6. The efficient high-ash coal gasification spiral reactor according to claim 5, characterized in that: The feed pipe is an L-shaped pipe, which includes a vertical section and a horizontal section. The modifier inlet and the high-temperature and high-pressure oxygen inlet are arranged on the vertical section. The end of the horizontal section extends into the ash collector and docks with the upper end of the spiral reaction tank. The high-temperature and high-pressure water inlet is arranged on the vertical section and is arranged opposite to the horizontal section. The diameter of the high-temperature and high-pressure water inlet is not greater than 1 / 5 of the sum of the diameters of the modifier inlet and the high-temperature and high-pressure oxygen inlet.

7. The efficient high-ash coal gasification spiral reactor according to claim 6, characterized in that: The flow rate of the high-temperature and high-pressure water is not less than 6 cm / s.

8. The efficient high-ash coal gasification spiral reactor according to claim 5, characterized in that: An electric heating wire or an electric heating belt is arranged on the outside of the feed pipe, and a temperature sensor is arranged on the feed pipe between the modifier inlet and the high-temperature and high-pressure oxygen inlet.

9. The efficient high-ash coal gasification spiral reactor according to any one of claims 1 to 8, characterized in that: An air inlet pipe connected to the ash collector is arranged at the lower end of the ash collector, and a conical distribution plate is arranged on the lower inner wall of the ash collector above the air inlet pipe. The distribution plate and the inner wall of the ash collector below form an air chamber, and a plurality of air holes are arranged on the distribution plate.

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