A dry ash removal gasifier with down-flow full waste pot gas flow bed for treating salt-containing wastewater

Abstract

This invention provides a downward-flowing, fully entrained wastewater gasifier for treating saline wastewater, relating to the field of gasifiers. It includes a combustion chamber, a radiant wastewater boiler, a quench chamber, an upward-sloping jacketed pipe, a convective wastewater boiler, and a dry ash removal device. The combustion chamber has a water-cooled wall or furnace brick structure, and a slag outlet is located at the bottom of the combustion chamber, connected to the radiant wastewater boiler. The bottom of the radiant wastewater boiler is connected to the quench chamber. The gas phase outlet of the radiant wastewater boiler is connected to the convective wastewater boiler via the upward-sloping jacketed pipe, and the outlet of the convective wastewater boiler is connected to the dry ash removal device. A saline wastewater ring and a slag guide pipe are provided at the slag outlet. The saline wastewater ring has multiple branches for supplying saline wastewater, and a vertically downward-sloping outlet is located at the bottom of the saline wastewater ring. The outer ring of the saline wastewater ring is connected to the slag guide pipe. This invention can solidify ash and slag, reduce the risk of slag collection and adhesion in the wastewater boiler, recover as much of the high-temperature sensible heat of the syngas as possible, and completely solve the problem of saline wastewater treatment.

Description

Technical Field

[0001] This invention relates to the field of gasifiers, and more specifically, to a downflow all-waste boiler fluidized bed dry ash removal gasifier for treating saline wastewater. Background Technology

[0002] Currently, the main gasifiers used for treating saline wastewater are coal-water slurry gasifiers.

[0003] The coal-water slurry was prepared using saline wastewater. The coal slurry reacted with pure oxygen in the furnace to generate high-temperature syngas, while the excess water (water introduced into the coal slurry) was vaporized. This caused the salt and silicon dissolved in the wastewater to precipitate out. A very small portion of the precipitate was encapsulated in the coarse slag, while the majority of the precipitate existed independently of the coarse and fine slags and eventually dissolved back into the system water. This method did not achieve the function of effectively treating saline wastewater.

[0004] Currently, the fluidized bed gasifier for dry ash removal is an upward-flowing waste boiler.

[0005] The upward-flowing waste heat boiler can only improve the water quality of its own system. Under the same coal feed rate and gasifier load, although it reduces external drainage, it cannot completely solve the problem of saline wastewater, meaning it cannot achieve true zero discharge. Furthermore, in the upward-flowing waste heat boiler gasifier, the syngas produced rises upwards while the molten slag falls downwards. The molten slag enters the quench chamber through the slag inlet (throat), falls into the water bath for quenching and cooling, and is then discharged. At the gasifier outlet, a large amount of quench gas (syngas produced by the gasifier after dust removal, cooling, and pressurization) is used to lower the temperature of the syngas and the molten slag it carries, preventing the syngas from carrying molten slag upwards and entering the convective waste heat boiler, where it would adhere to the water-cooled walls, affecting heat exchange and blocking the syngas passages. The main problems are: ① The amount of syngas quench gas is large, about 1 / 3 of the gas produced by the gasifier. Under normal design, the gasifier and auxiliary systems must be increased by another 30%, resulting in low production capacity per unit volume. At the same time, the syngas produced needs to be cooled and pressurized before being returned to the convection waste heat boiler, resulting in high energy consumption. ② The downward flow of molten slag relies solely on gravity, resulting in low flow velocity. This places stringent requirements on the size of the slag opening (lower slag section). A large slag opening leads to poor back-mixing effect and affects carbon conversion rate. A small slag opening is prone to blockage. Therefore, under a certain slag opening size and a certain load, the adaptability of coal is required to be stringent. The operating window of the coal must be greater than 120°C to ensure smooth slag discharge at the slag opening.

[0006] At the same time, there is no precedent for industrial operation of the downward flow bed dry ash removal gasification furnace.

[0007] Therefore, this application is hereby submitted. Summary of the Invention

[0008] The present invention includes, for example, providing a downflow all-waste boiler fluidized bed dry ash removal gasification furnace for treating saline wastewater.

[0009] The embodiments of the present invention can be implemented as follows:

[0010] In a first aspect, the present invention provides a downflow full-waste boiler fluidized bed dry ash removal gasification furnace for treating saline wastewater, comprising a combustion chamber, a radiant waste boiler, a quench chamber, an inclined upward jacket, a convection waste boiler, and a dry ash removal device. The combustion chamber is constructed of water-cooled walls or furnace bricks. A slag outlet is provided at the bottom of the combustion chamber, which is connected to the radiant waste boiler. The bottom of the radiant waste boiler is connected to the quench chamber. The gas phase outlet of the radiant waste boiler is connected to the convection waste boiler through the inclined upward jacket, and the outlet of the convection waste boiler is connected to the dry ash removal device.

[0011] A saline wastewater ring and a slag guide pipe are provided at the slag outlet. The saline wastewater ring is provided with multiple branches for providing saline wastewater. A vertically downward water outlet is provided at the bottom of the saline wastewater ring. The outer ring of the saline wastewater ring is connected to the slag guide pipe.

[0012] In an optional embodiment, the radiant waste boiler is provided with a first water-cooled wall and a second water-cooled wall, the second water-cooled wall is located outside the first water-cooled wall, the first water-cooled wall forms a central channel, the center is connected to the slag outlet, a return channel is formed between the first water-cooled wall and the second water-cooled wall, and the inclined upward jacket is connected to the top of the return channel.

[0013] Preferably, both the first water-cooled wall and the second water-cooled wall are equipped with rappers for dust removal;

[0014] Preferably, the inlet of the reversing channel is provided with a quench gas inlet for abnormal over-temperature protection;

[0015] Preferably, the top of the reversing channel is provided with a soot blowing gas inlet.

[0016] In an optional embodiment, the length of the second water-cooled wall is greater than that of the first water-cooled wall, and the lower end of the second water-cooled wall tapers inward to form a cone shape. The inner wall of the radiant waste pot is provided with an annular baffle and a liquid level protection gas inlet corresponding to the taper of the second water-cooled wall. An annular micro-opening sealing plate is provided above the taper of the second water-cooled wall. The annular micro-opening sealing plate is located between the second water-cooled wall and the inner wall of the radiant waste pot. The annular micro-opening sealing plate can selectively close or open the channel between the second water-cooled wall and the inner wall of the radiant waste pot to automatically balance the gas volume.

[0017] Preferably, the annular micro-opening sealing plate is connected to the inner wall of the radiant waste pot via a spring.

[0018] In an optional implementation, the reversal channel is provided with multiple sets of heat exchange fins;

[0019] Preferably, the heat exchange fins are in 8-16 groups, with 4-6 heat exchange fins in each group.

[0020] In an optional embodiment, the downflow waste boiler fluidized bed dry ash removal gasification furnace for treating saline wastewater further includes a cyclone separator, which is connected between the inclined upward jacket and the convective waste boiler. The gas outlet of the cyclone separator is connected to the convective waste boiler, and the ash outlet of the cyclone separator is connected to the dry ash removal device.

[0021] In an optional embodiment, the cyclone separator includes a separation chamber, a conical tube, and a conical shell. The bottom of the separation chamber tapers into a cone shape. The conical tube is connected to the lower part of the separation chamber, and the conical shell is connected to the taper position of the separation chamber. The conical tube is located inside the conical shell. A purge gas inlet is provided at the top of the conical shell, and three temperature sensing elements at different heights are provided at the bottom of the conical shell. The inlet line of the purge gas inlet is provided with a preheating purge protection gas line and a cooling gas line. A control valve group is provided on the cooling gas line, and the control valve group is connected to the temperature sensing elements.

[0022] In an optional embodiment, the dry ash removal device includes an ash collection tank, an ash discharge tank, a discharge tank filter, an ash cooler, and an ash silo. An ash filter is installed at the top of the ash collection tank. The ash filter is connected to the outlet of the cyclone separator and the outlet of the convective waste heat boiler. The ash collection tank is connected to the outlet of the ash filter. The ash discharge tank is connected to the outlet of the ash collection tank. The discharge tank filter is connected to the top gas outlet of the ash discharge tank. The ash cooler is connected to the bottom ash outlet of the ash discharge tank. The ash silo is connected to the ash cooler.

[0023] Preferably, the discharge tank is provided with a high-pressure air inlet for increasing the pressure inside the discharge tank, a high-pressure balancing valve is provided between the ash collection tank and the ash discharge tank, a pressure regulating valve is provided at the outlet of the discharge tank filter, and a low-pressure balancing valve is provided between the ash discharge tank and the ash cooler.

[0024] Preferably, the ash cooler is equipped with a water-cooled wall heat exchange tube assembly and a low-pressure nitrogen inlet;

[0025] Preferably, an ash cooling steam drum is also provided above the ash cooler, and the inlet and outlet of the water-cooled wall heat exchange tube assembly are connected to the ash cooling steam drum.

[0026] In an optional embodiment, the downflow whole waste boiler fluidized bed dry ash removal gasifier for treating saline wastewater further includes a protective gas buffer tank for providing soot blowing gas, quench gas and purging gas.

[0027] In an optional embodiment, the protective gas buffer tank is further provided with a protective gas preheater for heating the gas, and the protective gas used in the combustion chamber, the radiant waste boiler, and the convective waste boiler is all heated by the protective gas preheater.

[0028] In an optional embodiment, the downflow fluidized bed dry ash removal gasifier for treating saline wastewater further includes a syngas scrubbing tower. The middle inlet of the syngas scrubbing tower is connected to the top outlet of the dry ash removal device. The top outlet of the syngas scrubbing tower is connected to a protective gas compressor, and the protective gas compressor is connected to the protective gas buffer tank.

[0029] The beneficial effects of the embodiments of the present invention include, for example:

[0030] This invention provides a downward flow-bed dry ash removal gasification furnace for treating saline wastewater. By setting a saline wastewater ring and a slag guide pipe at the slag outlet, the saline wastewater can be used to cool the syngas and molten slag entering the radiant waste boiler, reducing the overall temperature from about 1450℃ to 950-1150℃, below the melting point of general ash slag, thus solidifying the ash slag and greatly reducing the risk of slag adhesion and ash collection in the waste boiler. Simultaneously, the wastewater discharged from the saline wastewater ring flows uniformly downwards along the inner wall of the slag guide pipe. Heat transfer occurs during this parallel downward flow of the saline wastewater, high-temperature molten slag, and syngas, further reducing the temperature of the ash slag. Water vaporizes into steam, which increases the water-to-gas ratio of syngas in the waste heat boiler, ensuring the water-to-gas ratio of the downstream converter. It also precipitates dissolved substances such as salt and silicon, and most of the precipitates and fine ash enter the dry ash removal system with the syngas and are discharged in solid form, completely solving the problem of saline wastewater treatment. Secondly, after adding saline wastewater, the syngas temperature at the waste heat boiler inlet is reduced to below 1000℃, which greatly reduces the heat exchange pressure of the radiant waste heat boiler and eliminates the need for the finned water-cooled wall in the central channel of the traditional radiant waste heat boiler. This simplifies the structure of the radiant waste heat boiler and eliminates the potential slag-carrying points inside, thus completely solving the problem of slag collection and adhesion inside the waste heat boiler from the root. The downflow full-waste boiler dry ash removal gasifier of this embodiment can completely solve the problem of saline wastewater treatment. The high-temperature sensible heat of the syngas is recovered as much as possible. The waste boiler channel structure of the gasifier is simple and the central channel is large, which reduces the risk of slagging and sticking. At the same time, this technology has significant advantages such as safe and reliable operation, high online operation rate, convenient operation and maintenance, low operating cost and low overall energy consumption, which greatly improves its economic value. Attached Figure Description

[0031] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of the structure of the downflow full-waste boiler fluidized bed dry ash removal gasification furnace for treating saline wastewater provided in this embodiment;

[0033] Figure 2 This is a schematic diagram of the combustion chamber and radiant waste boiler in the downflow full waste boiler dry ash removal gasifier for treating saline wastewater provided in this embodiment;

[0034] Figure 3 for Figure 2 A magnified view of a portion of point A in the middle.

[0035] Icons: 100 - Downward-flowing full-waste boiler dry ash removal gasification furnace for treating saline wastewater; 110 - Combustion chamber; 111 - Slag outlet; 112 - Saline wastewater ring; 113 - Slag guide pipe; 120 - Radiant waste boiler; 121 - First water-cooled wall; 122 - Second water-cooled wall; 123 - Central channel; 124 - Reversal channel; 1241 - Heat exchange fins; 125 - Quenching gas inlet; 126 - Soot blowing gas outlet; 127 - Annular baffle plate; 128 - Liquid level protection gas inlet; 129 - Annular slightly open sealing plate; 130 - Quenching chamber; 140 - Inclined upward jacketed tube; 150 - Cyclone separator; 151 - Separation chamber; 152 - Conical tube; 153 - Conical shell; 154-Purge gas inlet; 155-Temperature detection element; 156-Preheating purging protective gas pipeline; 157-Cooling gas pipeline; 160-Convection waste heat boiler; 170-Dry ash removal device; 171-Ash collection tank; 1711-Ash filter; 172-Ash discharge tank; 173-Discharge tank filter; 174-Ash cooler; 1741-Water-cooled wall heat exchanger tube assembly; 1742-Low-pressure nitrogen inlet; 175-Ash silo; 176-High-pressure balancing valve; 177-Pressure regulating valve; 178-Low-pressure balancing valve; 179-Ash cooling steam drum; 180-Protective gas buffer tank; 181-Protective gas preheater; 182-Protective gas compressor; 190-Synthesis gas scrubbing tower. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0037] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0038] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0039] In the description of this invention, it should be noted that if terms such as "upper," "lower," "inner," or "outer" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this invention is usually placed, they are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0040] Furthermore, the terms "first" and "second" are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0041] It should be noted that, where there is no conflict, the features in the embodiments of the present invention can be combined with each other.

[0042] Example

[0043] Please refer to Figure 1 and Figure 2 This embodiment provides a downward flow bed dry ash removal gasification furnace 100 for treating saline wastewater, which includes a combustion chamber 110, a radiant waste boiler 120, a quench chamber 130, an inclined upward jacketed pipe 140, a cyclone separator 150, a convective waste boiler 160, a dry ash removal device 170, a protective gas buffer tank 180, a protective gas preheater 181, and a syngas scrubbing tower 190.

[0044] Combustion chamber 110 is used to burn dry pulverized coal or coal-water slurry to produce syngas. Combustion chamber 110 has a water-cooled wall or furnace brick structure. The combustion chamber 110 uses a single top-mounted burner (not shown), multiple top-mounted burners (not shown), multiple side-mounted burners, or a combination of top-mounted and side-mounted multiple burners. A slag outlet 111 is provided at the bottom of combustion chamber 110, which communicates with radiant waste boiler 120. The qualified high-temperature syngas generated by combustion chamber 110 enters radiant waste boiler 120 through slag outlet 111. In this embodiment, a saline wastewater ring 112 and a slag guide pipe 113 are provided at slag outlet 111. The saline wastewater ring 112 has multiple branches for providing saline wastewater, and a vertically downward-facing outlet (not shown) is provided at the bottom of the saline wastewater ring 112. The outer ring of the saline wastewater ring 112 is connected to the slag guide pipe 113.

[0045] A vertically downwardly evenly distributed saline wastewater ring 112 is installed at the inner corner of the water-cooled wall coil of the slag outlet 111 and the horizontal wall water-cooled wall of the radiant waste boiler 120. This effectively prevents the high-temperature syngas from eroding and scouring the saline wastewater ring 112. The outlet of the saline wastewater ring 112 is connected to the slag guide pipe 113 of the nickel-based tube with the water-cooled wall coil. The slag guide pipe 113 serves multiple purposes: firstly, it guides the slag; too long a length affects the heat exchange efficiency of the waste boiler, while too short a length can cause slag to curl and adhere to the horizontal wall of the waste boiler. Therefore, in this embodiment, the length of the slag guide pipe 113 is 0.8D to 2D. Secondly, it wraps the slag, reducing the diffusion angle, i.e., reducing or eliminating the horizontal force, and preventing the slag from adhering to the water-cooled wall. Thirdly, it guides the wastewater discharged from the vertically downwardly evenly distributed saline wastewater ring 112. The slag flows uniformly downwards along the inner wall of the slag guide pipe 113. During the parallel downward flow of saline wastewater, high-temperature molten slag, and syngas, heat is transferred, causing the water in the saline wastewater to vaporize into steam. This increases the water-to-gas ratio of the syngas in the waste boiler, causing dissolved substances such as salt and silicon to precipitate. Most of the precipitates and fine ash enter the dry ash removal system with the syngas and are discharged in solid form. This completely solves the problem of excessive water in some areas or changes in the direction of syngas and molten slag when saline wastewater is added from the side, which ultimately leads to slag formation in the waste boiler. At the same time, it solves the problem of saline wastewater treatment. Secondly, after saline wastewater is uniformly added to the center of the waste boiler, the syngas and molten slag are cooled, reducing the overall temperature from about 1450℃ to 950-1150℃, which is lower than the melting point of general ash and slag. This causes the ash and slag to solidify, greatly reducing the risk of slag collection and adhesion in the waste boiler.

[0046] The radiant waste boiler 120 is used for heat exchange of high-temperature syngas. Under normal circumstances, fins are installed inside the radiant waste boiler 120 to enhance the heat exchange capacity. However, in this embodiment, after adding saline wastewater, the syngas temperature at the inlet of the waste boiler is about 950-1150℃, which greatly reduces the heat exchange pressure of the radiant waste boiler 120. Therefore, fins are no longer installed inside the radiant waste boiler 120 to increase the heat exchange capacity. This makes the structure of the radiant waste boiler 120 simple and eliminates the potential slag-carrying points inside. At the same time, the central channel 123 is also enlarged, which completely solves the problem of slag collection and adhesion inside the waste boiler from the root.

[0047] Specifically, in this embodiment, the radiant waste boiler 120 is provided with a first water-cooled wall 121 and a second water-cooled wall 122. Both the first water-cooled wall 121 and the second water-cooled wall 122 are annular. The second water-cooled wall 122 is located outside the first water-cooled wall 121. The first water-cooled wall 121 forms a central channel 123, which is connected to the slag outlet 111. A reversal channel 124 is formed between the first water-cooled wall 121 and the second water-cooled wall 122. The inclined upward jacket pipe 140 is connected to the top of the reversal channel 124. The high-temperature syngas enters the channel formed by the first water-cooled wall 121 through the slag outlet 111. After heat exchange, the syngas moves upward through the reversal channel 124 and is discharged into the inclined upward jacket pipe 140. The molten slag in the syngas falls into the quench chamber 130 below the radiant waste boiler 120 for cooling and then is discharged. In this embodiment, both the first water-cooled wall 121 and the second water-cooled wall 122 are equipped with rappers (not shown in the figure) for ash removal; the rappers can remove the fine ash attached to the first water-cooled wall 121 and the second water-cooled wall 122, so that this part of the fine ash falls into the quench chamber 130 below the radiant waste pot 120.

[0048] A quench gas inlet 125 for abnormal over-temperature protection is installed at the inlet of the reversing channel 124; and two sets of temperature detection facilities are installed within 500mm and 8000mm of the inlet of the inclined upward jacket pipe 140, with 4-12 temperature detection elements 155 in each set. After being discharged through the reversing channel 124, the synthesis gas enters the subsequent inclined upward jacket pipe 140, cyclone separator 150, and convective waste heat boiler 160. After one-step heat exchange and cooling, dry ash removal and water washing and dust removal, it enters the conversion unit. After adjusting the hydrogen-carbon ratio required by the downstream unit and removing water, most of it is sent to the downstream unit. A small portion is pressurized by the protective gas compressor 182 and then enters the protective gas buffer tank 180. The protective gas compressor 182 is a variable load compressor, that is, the load is selected according to the pressure of the protective gas buffer tank 180, and it normally operates at a low load. When the temperature detection element 155 detects an abnormal temperature (exceeding 750°C) due to coal quality or other reasons, quench gas can be introduced into the quench gas inlet 125. The quench gas can purge and cool the syngas at the inlet of the return channel 124 with a large volume of gas. When this occurs, the compressor automatically switches to high-load operation. After the operating conditions return to normal, it automatically switches back to low-load operation. Simultaneously, to prevent the quench gas inlet at the waste heat boiler return point from becoming clogged due to prolonged disuse, a bypass with a flow-limiting orifice plate is installed on the quench gas shut-off valve. During normal operation, this bypass serves as the continuous quench gas supply, preventing quench gas inlet blockage. This rational design minimizes energy consumption. Furthermore, in this embodiment, a soot blowing port 126 is provided at the top of the return channel 124.

[0049] Please see Figure 2 and Figure 3The second water-cooled wall 122 is longer than the first water-cooled wall 121, and the lower end of the second water-cooled wall 122 tapers inward to form a cone shape. The inner wall of the radiant waste pot 120 is provided with an annular baffle 127 and a liquid level protection gas inlet 128 corresponding to the taper of the second water-cooled wall 122. An annular micro-opening sealing plate 129 is provided above the taper of the second water-cooled wall 122. The annular micro-opening sealing plate 129 is located between the second water-cooled wall 122 and the inner wall of the radiant waste pot 120. The annular micro-opening sealing plate 129 can selectively close or open the channel between the second water-cooled wall 122 and the inner wall of the radiant waste pot 120 to automatically balance the gas volume. The annular micro-opening sealing plate 129 is connected to the inner wall of the radiant waste pot 120 by a spring. The protective gas entering through the liquid level protective gas inlet 128 is located below the constriction of the second water-cooled wall 122. Together with the annular baffle 127, it can slow down the upward movement of moisture in the quench chamber 130 and effectively prevent moisture in the quench chamber 130 from entering the dead zone of the waste boiler, thus preventing corrosion of the water-cooled wall on the dead zone side. In this embodiment, the annular micro-opening sealing plate 129 is designed in multiple segments. Each segment is held in place by multiple ropes (such as springs) with a certain deformation fixed to the wall surface, and a certain gap is always maintained. This ensures that the liquid surface gas is discharged upward normally and that the ash in the dead zone is discharged into the quench chamber 130 by gravity in a timely manner. When the gasifier system experiences abnormal pressure relief, the increased pressure difference causes the springs to deform and lengthen, and the annular micro-opening sealing plate 129 is fully opened. The gas in the dead zone is connected to the main circuit through the water bath of the quench chamber 130, achieving automatic balance and ensuring the safety and reliability of the water-cooled wall. This prevents the protective gas in the dead zone from failing to be discharged in time through the balance hole when the syngas main circuit system experiences rapid abnormal pressure relief, which could lead to an excessive pressure difference between the inside and outside of the water-cooled wall on the outside of the waste boiler return channel 124 and damage to the water-cooled wall.

[0050] To increase the heat exchange area and prevent uncured ash carried in the local syngas from adhering to the return channel 124, multiple sets of heat exchange fins 1241 are installed above 3000mm of the second set of temperature detection facilities (within 800mm) in the return channel 124. There are 8-16 sets of heat exchange fins 1241, with 6 fins in each set. The heat exchange fins 1241 can enhance the heat exchange effect within the return channel 124. The upper section of the heat exchange fins 1241 directly passes through the horizontal water-cooled wall of the waste boiler, reducing the risk of ash accumulation. At the same time, a soot blowing port is set at the connection between the second water-cooled wall 122 and the horizontal water-cooled wall for regular purging to prevent ash accumulation. In addition, an ash removal port is also set at the outlet of the return channel 124 for regular purging. The heat exchange fins 1241 installed in the reversing channel 124 have a high recovery rate of sensible heat from the synthesis gas and a large amount of recovered heat. Simultaneously, the heat exchange fins 1241 installed in the reversing channel 124 lower the outlet temperature, reducing the heat exchange pressure on the convective waste heat boiler 160; with the aforementioned 96000 Nm... 3Taking / h effective gas (CO+H2) as an example, the temperature of the convective waste boiler 160 is reduced to about 400℃, and the volume and heat exchange area of ​​the convective waste boiler 160 are greatly reduced. This significantly reduces both equipment investment and civil engineering investment in the plant layout. Moreover, the water content of the synthesized gas after exiting the dry ash removal system can still reach as high as 30%, close to the quench process, and is sent downstream to ensure the water-to-gas ratio of the downstream conversion unit. No additional steam needs to be added, and at least 120 tons of by-product steam are produced.

[0051] The quench chamber 130 is connected to the bottom of the radiant waste pot 120, and the quench chamber 130 is used to cool the slag carried in the synthesis gas.

[0052] Syngas in the return channel 124 of the radiant waste heat boiler 120 is led out through the inclined upward jacket pipe 140. The inclination of the inclined upward jacket pipe 140 is less than 35° (angle with the vertical direction). In some embodiments, when the cyclone separator 150 is not included, the inclined upward jacket pipe 140 is directly connected to the convective waste heat boiler 160. In some embodiments, when the cyclone separator 150 is included, the inclined upward jacket pipe 140 and the cyclone separator 150 are connected. In this case, the cyclone separator 150 is connected between the inclined upward jacket pipe 140 and the convective waste heat boiler 160. The gas outlet of the cyclone separator 150 is connected to the convective waste heat boiler 160, and the ash outlet of the cyclone separator 150 is connected to the dry ash removal device 170.

[0053] Specifically, the cyclone separator 150 includes a separation chamber 151, a cone tube 152, and a cone shell 153. The separation chamber 151 is made of refractory brick, coil, or jacket structure. The cone tube 152 is made of nickel-based alloy or nickel-based alloy tube with cooling half-pipe. The bottom of the separation chamber 151 is tapered into a cone shape. The cone tube 152 is connected to the lower part of the separation chamber 151. The cone shell 153 is connected to the tapered position of the separation chamber 151. The cone tube 152 is located inside the cone shell 153. The top of the cone shell 153 has a purge gas inlet 154. Three purge gas outlets are arranged circumferentially inside the cone shell 153. The included angle between each purge gas outlet is 120°. Three temperature sensing elements 155 at different heights are installed at the bottom of the conical shell 153. The inlet pipeline of the purge gas inlet 154 is equipped with a preheating purge protection gas pipeline 156 and a cooling gas pipeline 157. A control valve group is installed on the cooling gas pipeline 157, and the control valve group is connected to the temperature sensing elements 155. The purge gas discharged from the purge gas outlet continuously blows downwards. The purge gas discharged through the preheating purge protection gas pipeline 156 comes from the synthesis gas heated by the protection gas preheater 181 in the protection gas buffer tank 180, providing discharge power for the separated ash and discharging it into the fine ash collection tank 171, while simultaneously preventing high-temperature gas from entering the bottom of the conical hopper. The purge gas discharged through the cooling gas pipeline 157 comes from the unheated synthesis gas in the protection gas buffer tank 180. When the temperature of the discharged fine ash is too high, the cooling gas is opened in time to purge and cool down the ash, preventing the downstream high-pressure fine ash collection tank 171 from overheating.

[0054] The convective waste heat boiler 160 has a vertical cylindrical water-cooled wall and an inner core wound tube water-cooled wall. The syngas carries almost no slag. Due to the vertical arrangement, the ash carried by the syngas enters the downstream dry ash removal device 170 with the syngas. The risk of ash accumulation on the inner core wound tube water-cooled wall is small. This design has relatively high heat exchange efficiency. Soot blowing ports and rapping soot blowing facilities are set on the cylindrical water-cooled wall and the inner core wound tube water-cooled wall of the convective waste heat boiler 160 to regularly clean the ash on the water-cooled wall surface, ensuring the heat exchange effect of the water-cooled wall tubes, and at the same time ensuring that the inner core wound tube water-cooled wall does not accumulate ash.

[0055] Cyclone separator 150 is connected to dry ash removal device 170 through a downwardly inclined jacket pipe. The inclination of the jacket pipe is less than 30° (angle with the vertical direction). The outlet of the downwardly inclined jacket pipe is connected to the dry ash removal device 170.

[0056] The dry ash removal device 170 is used to remove fine ash from the syngas. In this embodiment, the dry ash removal device 170 is connected to the outlet of the convective waste heat boiler 160. When this embodiment also includes a cyclone separator 150, the dry ash removal device 170 is also connected to the outlet of the cyclone separator 150. The syngas exiting the top of the cyclone separator 150 enters the convective waste heat boiler 160 for further heat recovery before entering the dry ash removal device 170.

[0057] Specifically, the dry ash removal device 170 includes an ash collection tank 171, an ash discharge tank 172, a discharge tank filter 173, an ash cooler 174, and an ash silo 175. An ash filter 1711 is installed at the top of the ash collection tank 171. The ash filter 1711 is connected to the outlet of the cyclone separator 150 and the outlet of the convective waste heat boiler 160. The ash collection tank 171 is connected to the outlet of the ash filter 1711. The ash discharge tank 172 is connected to the outlet of the ash collection tank 171. The discharge tank filter 173 is connected to the top gas outlet of the ash discharge tank 172. The ash cooler 174 is connected to the bottom ash outlet of the ash discharge tank 172. The ash silo 175 is connected to the ash cooler 174. The discharge tank is equipped with a high-pressure gas inlet for increasing the pressure inside the discharge tank. A high-pressure balancing valve 176 is installed between the ash collection tank 171 and the ash discharge tank 172. A pressure regulating valve 177 is installed at the outlet of the discharge tank filter 173. A low-pressure balancing valve 178 is installed between the ash discharge tank 172 and the ash cooler 174. The ash cooler 174 is equipped with a water-cooled wall heat exchange tube assembly 1741 and a low-pressure nitrogen inlet 1742. An ash cooling steam drum 179 is also installed above the ash cooler 174. The inlet and outlet of the water-cooled wall heat exchange tube assembly 1741 are connected to the ash cooling steam drum 179.

[0058] The ash discharge process of the dry ash removal device 170 is as follows: Fine ash in the ash collection tank 171 is periodically discharged into the ash discharge tank 172 by a program. Before discharge, high-pressure CO2 is introduced into the ash discharge tank 172 through the high-pressure gas inlet to pressurize it to the operating pressure of the ash collection tank 171. Then, the high-pressure balancing valve 176 in both the ash collection tank 171 and the ash discharge tank 172 is opened to balance the pressure of the two tanks. After ensuring normal breathing and exhaust during discharge, the discharge valve group of the ash collection tank 171 is opened, and the fine ash collected in the ash collection tank 171 is discharged into the ash discharge tank 172 by gravity flow. Then, the discharge valve and the high-pressure balancing valve 176 are closed, completely isolating the ash collection tank 171 and the ash discharge tank 172. Finally, the pressure regulating valve 177 at the outlet of the discharge tank filter 173 is opened to release the pressure in the ash discharge tank 172 to a slightly positive pressure, and the ash discharge tank 172 is discharged. After opening the low-pressure balancing valve 178 in the ash cooler 174 to balance the pressure of the two tanks and ensure normal breathing and venting during material discharge, open the discharge valve group of the ash discharge tank 172. The fine ash in the ash discharge tank 172 is discharged to the ash cooler 174 by gravity flow. Then, close the discharge valve group and the low-pressure balancing valve 178 to completely isolate the ash discharge tank 172 and the ash cooler 174. Then, close the low-pressure balancing valve 178 at the outlet of the discharge tank filter 173 and open the pressurizing gas CO2 in the ash discharge tank 172 to pressurize the ash discharge tank 172 again to the operating pressure of the ash collection tank 171. Then, open the high-pressure balancing valve 176 in the ash collection tank 171 and the ash discharge tank 172 to balance the pressure of the two tanks and ensure normal breathing and venting during material discharge. Then, open the discharge valve group of the ash collection tank 171 to enter the normal ash collection stage. After the ash collection is full, the cycle continues to the next step, with the same steps as above.

[0059] The protective gas buffer tank 180 is used to provide soot blowing gas, quench gas, and purge gas to the downflow all-waste boiler fluidized bed dry ash removal gasification furnace 100 for treating saline wastewater. In this embodiment, all locations where soot blowing gas, quench gas, and purge gas are provided need to be connected to the protective gas buffer tank 180. This ensures the device has advantages such as high safety and stability during online operation, long cycle time, and good economy.

[0060] The protective gas preheater 181 is used to heat the soot blowing gas and purging gas that need to be heated, so as to avoid the temperature difference between the soot blowing gas or purging gas and the device during purging. In this embodiment, the protective gas used in the combustion chamber 110 radiant waste pot 120 and the convective waste pot 160 are all heated by the protective gas preheater 181.

[0061] Syngas scrubbing tower 190 is used to scrub the syngas after ash removal. The middle inlet of syngas scrubbing tower 190 is connected to the top outlet of dry ash removal device 170. The top outlet of syngas scrubbing tower 190 is connected to protective gas compressor 182. Protective gas compressor 182 is connected to protective gas buffer tank 180.

[0062] The working principle of the downward flow-flow dry ash removal gasification furnace 100 for treating saline wastewater according to this embodiment is as follows:

[0063] Dry pulverized coal or coal-water slurry enters the combustion chamber 110 for combustion. The resulting syngas and molten slag flow downwards through the slag outlet 111 into the central channel 123 of the radiant waste boiler 120. Since the slag outlet 111 is equipped with a saline wastewater ring 112 and a slag guide pipe 113, the saline wastewater is introduced into the saline wastewater ring 112 and flows downwards along the slag guide pipe 113. During this parallel downward flow of saline wastewater, high-temperature molten slag, and syngas, heat transfer occurs, causing the water in the saline wastewater to vaporize into steam, increasing the syngas-to-water ratio within the radiant waste boiler 120. Salt-containing silicon and other dissolved substances precipitate out, and most of the precipitates and fine ash enter the dry ash removal system with the syngas and are discharged in solid form. This completely solves the problem of excessive water or altered syngas and slag direction caused by the side addition of salt-containing wastewater, which ultimately leads to slag formation in the waste boiler. At the same time, it solves the problem of salt-containing wastewater treatment. Secondly, after uniformly adding salt-containing wastewater to the center of the waste boiler, the syngas and slag are cooled, reducing the overall temperature from about 1450℃ to 950-1150℃, which is lower than the melting point of general ash and slag, thus solidifying the ash and slag and greatly reducing the risk of slag collection and adhesion in the waste boiler. After being cooled by the first water-cooled wall 121, the syngas enters the return channel 124 from the bottom of the first water-cooled wall 121 and moves upward to further recover sensible heat. The annular baffle 127, the liquid level protection gas inlet 128, and the annular micro-opening sealing plate 129 installed in the return channel 124 can effectively prevent moisture in the quench chamber 130 from entering the waste boiler dead zone and causing corrosion of the water-cooled wall on the dead zone side. In addition, when the gasifier system experiences abnormal pressure relief, the annular micro-opening sealing plate 129 can achieve automatic balance to ensure the safety and reliability of the water-cooled wall. This prevents the protection gas in the dead zone from failing to be discharged in time through the balance hole when the syngas main pipeline system experiences rapid abnormal pressure relief, which could lead to excessive pressure difference between the inside and outside of the water-cooled wall on the outside of the waste boiler return channel 124 and damage to the water-cooled wall. In addition, to ensure the heat exchange effect of the turnaround channel 124, heat exchange fins 1241 are installed in the turnaround channel 124 to increase the heat exchange effect. After the syngas exits the turnaround channel 124, it is connected in sequence to the cyclone separator 150 (the cyclone separator 150 may not be installed if the ash content is low, depending on the characteristics of the coal selected for the project), the convective waste heat boiler 160, the dry ash removal device 170, and the syngas scrubbing tower 190 before being washed and discharged. The coarse slag is cooled in the water bath of the quench chamber 130 and then discharged through the slag discharge system.

[0064] In summary, this invention provides a downward flow-bed dry ash removal gasification furnace 100 for treating saline wastewater. By setting a saline wastewater ring 112 and a slag guide pipe 113 at the slag outlet 111, the saline wastewater can be used to cool the syngas and molten slag entering the radiant waste boiler 120, reducing the overall temperature from approximately 1450℃ to 950-1150℃, below the melting point of general ash slag, thus solidifying the ash slag and greatly reducing the risk of slag collection and adhesion in the waste boiler. Simultaneously, the wastewater discharged from the saline wastewater ring 112 flows uniformly downwards along the inner wall of the slag guide pipe 113, and the saline wastewater flows downwards in parallel with the high-temperature molten slag and syngas. Heat transfer causes the water in the saline wastewater to vaporize into steam, which increases the water-to-gas ratio of the syngas in the waste boiler, ensuring the water-to-gas ratio of the downstream converter. It also precipitates dissolved substances such as salt and silicon, and most of the precipitates and fine ash enter the dry ash removal system with the syngas and are discharged in solid form, completely solving the problem of saline wastewater treatment. Secondly, after adding saline wastewater, the syngas temperature at the waste boiler inlet is reduced to below 1000℃, which greatly reduces the heat exchange pressure of the radiant waste boiler 120 and eliminates the need for the finned water-cooled wall in the central channel 123 of the traditional radiant waste boiler 120. This simplifies the structure of the radiant waste boiler 120 and eliminates the potential slag-carrying points inside, thus completely solving the problem of slag collection and adhesion inside the waste boiler from the root. The downflow full-waste boiler dry ash removal gasifier 100 used in this embodiment for treating saline wastewater can completely solve the problem of saline wastewater treatment. It recovers as much of the high-temperature sensible heat of the syngas as possible. The waste boiler channel structure of the gasifier is simple, with a large central channel 123, which reduces the risk of slagging and sticking. At the same time, this technology has significant advantages such as safe and reliable operation, high online operation rate, convenient operation and maintenance, low operating cost and low overall energy consumption, which greatly improves its economic value.

[0065] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A downward-flowing, fully wastewater-generating fluidized bed dry ash removal gasification furnace for treating saline wastewater, characterized in that, It includes a combustion chamber, a radiant waste boiler, a quench chamber, an upwardly inclined jacketed pipe, a convection waste boiler, and a dry ash removal device. The combustion chamber has a water-cooled wall or furnace brick structure. A slag outlet is provided at the bottom of the combustion chamber and is connected to the radiant waste boiler. The bottom of the radiant waste boiler is connected to the quench chamber. The gas phase outlet of the radiant waste boiler is connected to the convection waste boiler through the upwardly inclined jacketed pipe, and the outlet of the convection waste boiler is connected to the dry ash removal device. A saline wastewater ring and a slag guide pipe are provided at the slag outlet. The saline wastewater ring is provided with multiple branches for providing saline wastewater. A vertically downward water outlet is provided at the bottom of the saline wastewater ring. The outer ring of the saline wastewater ring is connected to the slag guide pipe.

2. The downflow all-waste boiler fluidized bed dry ash removal gasification furnace for treating saline wastewater according to claim 1, characterized in that, The radiant waste boiler is provided with a first water-cooled wall and a second water-cooled wall. The second water-cooled wall is located outside the first water-cooled wall. The first water-cooled wall forms a central channel, which is connected to the slag outlet. A reversing channel is formed between the first water-cooled wall and the second water-cooled wall. The inclined upward jacket is connected to the top of the reversing channel.

3. The downflow all-waste boiler fluidized bed dry ash removal gasification furnace for treating saline wastewater according to claim 2, characterized in that, Both the first water-cooled wall and the second water-cooled wall are equipped with rappers for dust removal.

4. The downflow all-waste boiler fluidized bed dry ash removal gasification furnace for treating saline wastewater according to claim 2, characterized in that, The inlet of the reversing channel is equipped with a quench gas inlet for abnormal over-temperature protection.

5. The downflow all-waste boiler fluidized bed dry ash removal gasification furnace for treating saline wastewater according to claim 2, characterized in that, The top of the reversing channel is equipped with a soot blowing gas inlet.

6. The downflow all-waste boiler fluidized bed dry ash removal gasification furnace for treating saline wastewater according to claim 2, characterized in that, The second water-cooled wall is longer than the first water-cooled wall, and the lower end of the second water-cooled wall tapers inward to form a cone shape. The inner wall of the radiant waste pot is provided with an annular baffle and a liquid level protection gas inlet corresponding to the taper of the second water-cooled wall. An annular micro-opening sealing plate is provided above the taper of the second water-cooled wall. The annular micro-opening sealing plate is located between the second water-cooled wall and the inner wall of the radiant waste pot. The annular micro-opening sealing plate can selectively close or open the channel between the second water-cooled wall and the inner wall of the radiant waste pot to automatically balance the gas volume.

7. The downflow all-waste boiler fluidized bed dry ash removal gasification furnace for treating saline wastewater according to claim 6, characterized in that, The annular micro-opening sealing plate is connected to the inner wall of the radiation waste pot by a spring.

8. The downflow all-waste boiler fluidized bed dry ash removal gasification furnace for treating saline wastewater according to claim 2, characterized in that, The reversal channel is equipped with multiple sets of heat exchange fins.

9. The downflow all-waste boiler fluidized bed dry ash removal gasification furnace for treating saline wastewater according to claim 8, characterized in that, The heat exchange fins are in 8-16 groups, with 4-6 heat exchange fins in each group.

10. The downflow all-waste boiler fluidized bed dry ash removal gasification furnace for treating saline wastewater according to claim 1, characterized in that, The downward flow-flow dry ash removal gasification furnace for treating saline wastewater also includes a cyclone separator. The cyclone separator is connected between the inclined upward jacket and the convective waste boiler. The gas outlet of the cyclone separator is connected to the convective waste boiler, and the ash outlet of the cyclone separator is connected to the dry ash removal device.

11. The downflow all-waste boiler fluidized bed dry ash removal gasification furnace for treating saline wastewater according to claim 10, characterized in that, The cyclone separator includes a separation chamber, a conical tube, and a conical shell. The bottom of the separation chamber tapers into a cone shape. The conical tube is connected to the lower part of the separation chamber, and the conical shell is connected to the taper position of the separation chamber. The conical tube is located inside the conical shell. A purge gas inlet is provided at the top of the conical shell, and three temperature sensing elements at different heights are provided at the bottom of the conical shell. The inlet pipeline of the purge gas inlet is provided with a preheating purge protection gas pipeline and a cooling gas pipeline. A control valve group is provided on the cooling gas pipeline, and the control valve group is connected to the temperature sensing elements.

12. The downflow all-waste boiler fluidized bed dry ash removal gasification furnace for treating saline wastewater according to claim 11, characterized in that, The dry ash removal device includes an ash collection tank, an ash discharge tank, a discharge tank filter, an ash cooler, and an ash silo. An ash filter is installed at the top of the ash collection tank. The ash filter is connected to the outlet of the cyclone separator and the outlet of the convective waste heat boiler. The ash collection tank is connected to the outlet of the ash filter. The ash discharge tank is connected to the outlet of the ash collection tank. The discharge tank filter is connected to the top gas outlet of the ash discharge tank. The ash cooler is connected to the bottom ash outlet of the ash discharge tank. The ash silo is connected to the ash cooler.

13. The downflow all-waste boiler fluidized bed dry ash removal gasification furnace for treating saline wastewater according to claim 12, characterized in that, The discharge tank is equipped with a high-pressure air inlet for increasing the pressure inside the discharge tank. A high-pressure balancing valve is provided between the ash collection tank and the ash discharge tank. A pressure regulating valve is provided at the outlet of the discharge tank filter. A low-pressure balancing valve is provided between the ash discharge tank and the ash cooler.

14. The downflow all-waste boiler fluidized bed dry ash removal gasification furnace for treating saline wastewater according to claim 12, characterized in that, The ash cooler is equipped with a water-cooled wall heat exchange tube assembly and a low-pressure nitrogen inlet.

15. The downflow all-waste boiler fluidized bed dry ash removal gasification furnace for treating saline wastewater according to claim 12, characterized in that, An ash cooling steam drum is also installed above the ash cooler, and the inlet and outlet of the water-cooled wall heat exchange tube assembly are connected to the ash cooling steam drum.

16. The downflow all-waste boiler fluidized bed dry ash removal gasification furnace for treating saline wastewater according to claim 1, characterized in that, The downflow all-waste boiler fluidized bed dry ash removal gasifier for treating saline wastewater also includes a protective gas buffer tank for providing soot blowing gas, quench gas and purging gas.

17. The downflow all-waste boiler fluidized bed dry ash removal gasification furnace for treating saline wastewater according to claim 16, characterized in that, The protective gas buffer tank is also equipped with a protective gas preheater for heating the gas. The protective gas used in the combustion chamber, the radiant waste boiler, and the convective waste boiler is all heated by the protective gas preheater.

18. The downflow all-waste boiler fluidized bed dry ash removal gasification furnace for treating saline wastewater according to claim 16, characterized in that, The downflow fluidized bed dry ash removal gasification furnace for treating saline wastewater also includes a syngas scrubbing tower. The middle inlet of the syngas scrubbing tower is connected to the top outlet of the dry ash removal device. The top outlet of the syngas scrubbing tower is connected to a protective gas compressor. The protective gas compressor is connected to the protective gas buffer tank.

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