CN112500892B - Integrated treatment device and method for gasification and fly ash melting of circulating fluidized bed - Google Patents
Integrated treatment device and method for gasification and fly ash melting of circulating fluidized bed Download PDFInfo
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- CN112500892B CN112500892B CN201910870647.2A CN201910870647A CN112500892B CN 112500892 B CN112500892 B CN 112500892B CN 201910870647 A CN201910870647 A CN 201910870647A CN 112500892 B CN112500892 B CN 112500892B
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- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
- C10J3/00—Production of combustible gases containing carbon monoxide from solid carbonaceous fuels
- C10J3/46—Gasification of granular or pulverulent flues in suspension
- C10J3/54—Gasification of granular or pulverulent fuels by the Winkler technique, i.e. by fluidisation
- C10J3/56—Apparatus; Plants
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- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
- C10J3/00—Production of combustible gases containing carbon monoxide from solid carbonaceous fuels
- C10J3/72—Other features
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- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
- C10J3/00—Production of combustible gases containing carbon monoxide from solid carbonaceous fuels
- C10J3/72—Other features
- C10J3/82—Gas withdrawal means
- C10J3/84—Gas withdrawal means with means for removing dust or tar from the gas
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Abstract
The invention provides a circulating fluidized bed gasification and fly ash melting integrated treatment device and method. The integrated treatment device for gasification in a circulating fluidized bed and melting of fly ash comprises a gasification furnace (1), a separation device and a material returning device (3) which form a circulation loop, the treatment device further comprises a melting device, the melting device is communicated with the separation device, so that the product treated by the separation device can be supplied to the melting device, and the melting device is also communicated with the gasification furnace (1), so that the product treated by the melting device can be supplied to the gasification furnace (1). The device and the method for integrated treatment of gasification of the circulating fluidized bed and melting of the fly ash can simultaneously realize the harmless treatment of the gasification and the fly ash.
Description
Technical Field
The invention relates to the technical field of fuel gasification and melting, in particular to a circulating fluidized bed gasification technology and a high-temperature melting technology, and specifically relates to a circulating fluidized bed gasification and fly ash melting integrated treatment device and method.
Background
The fluidized bed coal gasification technology includes a conventional fluidized bed coal gasification technology and a circulating fluidized bed coal gasification technology developed in recent years. Fluidized bed coal gasification technology has many advantages: crushed coal of 0-l 0mm can be used without screening, and the processing cost is low; the gasification intensity is high and can reach 2 to 3 times of that of the moving bed; air gasification can be used, and oxygen consumption is low; the temperature of the crude gas outlet is high; the product gas contains almost no tar, phenols and the like.
For the traditional fluidized bed coal gasifier, because the gasification operation temperature is low and the fluidization speed is high, although large particles of unreacted carbon can participate in the reaction again through circulation, the carbon content in the fly ash carried by the airflow is still considerable, generally the fly ash accounts for 70-80% of the total ash content, the mass fraction of the carbon in the fly ash accounts for 30-50%, and if the carbon in the fly ash can not be effectively utilized, the total carbon utilization rate of the system is low; in addition, the utilization and disposal of the fly ash are also a great problem due to the large amount of ash and high carbon content of the gasified fly ash.
The circulating fluidized bed coal gasifier developed in recent years is provided with a material circulation loop with high circulation volume, the fluidization speed is higher than that of the traditional fluidized bed coal gasifier, the circulating fluidized bed coal gasifier has the advantages of strong coal type applicability, full gas-solid mixing, high gasification reaction rate, uniform reactor temperature, capability of realizing low-cost desulfurization in the gasifier by adding limestone and the like, and has wider application prospect. However, this process also faces the problem of utilization and disposal of the fly ash.
Chinese patent application CN107043641A discloses a circulating fluidized bed coal gasification method and apparatus with fly ash return, in this application, fly ash generated in gasification process is returned to melting device for melting treatment, high temperature gas and high temperature slag generated by melting are returned to hearth of circulating fluidized bed coal gasification furnace, further realizing melting treatment of fly ash, increasing carbon conversion rate of system, and reducing pollution to environment.
In order to solve the problem of treatment of the fly ash after gasification of the circulating fluidized bed, the prior art provides the method and the device for gasification of the circulating fluidized bed with fly ash melting, but because the fly ash belongs to low-volatile fuel, the fly ash melting furnace in the prior art utilizes a preheating device to preheat the fly ash and then enters the melting furnace, so that the system is relatively complex, and the operation risk and the construction cost of the system are increased.
Disclosure of Invention
The invention aims to overcome the defects of the prior art at least partially and provides a device and a method for integrated treatment of gasification and fly ash fusion of a circulating fluidized bed, which can realize the gasification and the harmless treatment of the fly ash at the same time.
The invention also aims to provide a device and a method for integrated treatment of gasification and fly ash melting of a circulating fluidized bed, which have a simplified structure for treating the fly ash melting, so that the whole system is more stable and the operation is simpler.
The invention also aims to provide a circulating fluidized bed gasification and fly ash melting integrated treatment device and method with lower construction cost.
To achieve one of the above objects or purposes, the technical solution of the present invention is as follows:
a circulating fluidized bed gasification and fly ash fusion integrated treatment device comprises a gasification furnace, a separation device and a material returning device which form a circulating loop, the treatment device further comprises a fusion device, the fusion device is communicated with the separation device, so that a product treated by the separation device can be supplied to the fusion device, and the fusion device is also communicated with the gasification furnace, so that a product treated by the fusion device can be supplied to the gasification furnace.
According to a preferred embodiment of the present invention, the melting device is communicated with a middle or upper portion of the gasification furnace.
According to a preferred embodiment of the invention, the melting device is provided with an oxidant inlet.
According to a preferred embodiment of the present invention, the melting device includes a melting furnace burner and a melting furnace, the melting furnace burner communicates with the separation device, and the melting furnace communicates with the gasification furnace.
According to a preferred embodiment of the invention, the separation device comprises a primary cyclone separator and a secondary cyclone separator, the gas outlet of the primary cyclone separator is communicated with the inlet of the secondary cyclone separator, the solid material outlet of the primary cyclone separator is communicated with the material returning device, and the solid material outlet of the secondary cyclone separator is communicated with the melting device.
According to a preferred embodiment of the invention, the solid material outlet of the secondary cyclone is in communication with the gasification fly ash inlet of the melter burner.
According to a preferred embodiment of the invention, a communication duct is provided between the downstream of the gas outlet of the secondary cyclone and the downstream of the solid matter outlet of the secondary cyclone for conveying part of the gas discharged from the gas outlet of the secondary cyclone as pneumatic conveying gas for feeding the first gasified fly ash discharged from the solid matter outlet of the secondary cyclone to the melting furnace burner.
According to a preferred embodiment of the invention, the treatment device further comprises a tail treatment system comprising an inlet, a fly ash outlet and a product gas outlet, the inlet of the tail treatment system being in communication with the gas outlet of the secondary cyclone, the fly ash outlet being in communication with the melting device.
According to a preferred embodiment of the invention, the fly ash outlet is in communication with the melting furnace.
According to a preferred embodiment of the invention, the melting device comprises a first oxidant inlet arranged on a burner of the melting furnace and a second oxidant inlet arranged on the melting furnace.
According to a preferred embodiment of the invention, the tail treatment system comprises an air preheater, a waste heat boiler, a dust separator and a gas cooler.
According to a preferred embodiment of the present invention, the air preheater, the exhaust-heat boiler, the dust collector and the gas cooler are in communication in this order, the inlet of the tail treatment system is in communication with the air preheater, the product gas outlet of the tail treatment system is in communication with the gas cooler, and the fly ash outlet of the tail treatment system is in communication with the dust collector.
According to a preferred embodiment of the present invention, a communication duct is provided between the connection passage between the dust collector and the gas cooler and the connection passage between the dust collector and the fly ash outlet for pneumatically conveying a portion of the gas discharged from the dust collector to send the second gasified fly ash discharged from the dust collector to the melting furnace.
According to a preferred embodiment of the present invention, the air preheater, the exhaust-heat boiler, the gas cooler and the dust remover are in communication in this order, the inlet of the tail treatment system is in communication with the air preheater, the product gas outlet of the tail treatment system is in communication with the dust remover, and the fly ash outlet of the tail treatment system is in communication with the dust remover.
According to a preferred embodiment of the present invention, a communication duct is provided between the connection path between the waste heat boiler and the gas cooler and the connection path between the dust collector and the fly ash outlet, for using a part of the gas discharged from the waste heat boiler as pneumatic conveying gas to send the second gasified fly ash discharged from the dust collector to the melting furnace.
According to a preferred embodiment of the invention, the melting furnace is provided with a slag outlet which is not in communication with the gasification furnace.
According to a preferred embodiment of the present invention, the melter-gasifier is in communication with the gasifier through a melter nozzle.
According to another aspect of the present invention, there is provided a method of integrated treatment of circulating fluidized bed gasification and fly ash melting, using the integrated treatment apparatus of circulating fluidized bed gasification and fly ash melting as described in any one of the preceding embodiments.
According to a preferred embodiment of the invention, the flue gas produced by the melting device is passed into the gasifier together with the slag.
According to a preferred embodiment of the invention, the flue gas produced by the melting device is passed into the gasification furnace and the slag produced by the melting device is discharged from the melting device but not passed into the gasification furnace.
According to a preferred embodiment of the invention, the slag entering the gasifier is cooled in the gasifier to form a granular solid which is discharged from the bottom of the gasifier.
According to a preferred embodiment of the invention, the gasified fly ash and the oxidizer are subjected to a combustion or gasification reaction in the melting device.
According to a preferred embodiment of the invention, the second gasification fly ash enters the melting furnace from a side wall surface of the melting furnace close to the melting furnace burner.
According to a preferred embodiment of the invention, the gas conveying the first gasified fly ash as pneumatic conveying gas accounts for 5% -10% of the gas discharged from the gas outlet of the secondary cyclone.
According to a preferred embodiment of the invention, the gas conveying the second gasified fly ash as pneumatic conveying gas accounts for 3% -5% of the gas discharged from the dust separator.
According to a preferred embodiment of the invention, the gas conveying the second gasification fly ash as pneumatic conveying gas accounts for 3-5% of the gas discharged from the waste heat boiler.
According to a preferred embodiment of the present invention, the gasifying agent introduced into the gasification furnace, the first oxidizing agent introduced into the burner of the melting furnace, and the second oxidizing agent introduced into the melting furnace are all or partially preheated by an air preheater or a waste heat boiler provided in the tail treatment system and then introduced into the melting device.
According to a preferred embodiment of the invention, the temperature of the gasification furnace is controlled to be kept between 800 ℃ and 1000 ℃.
According to a preferred embodiment of the invention, the temperature of the melting furnace is controlled to be kept between 1300 ℃ and 1600 ℃.
According to a preferred embodiment of the invention, the gasifying agent is oxygen, air or steam, or a mixture of two or three.
According to a preferred embodiment of the invention, the first oxidant is oxygen or air or a mixture of both and/or the second oxidant is oxygen or air or a mixture of both.
The device and the method for integrated treatment of gasification and fly ash fusion of the circulating fluidized bed realize integrated treatment of gasification and fly ash fusion, improve the carbon conversion rate of the circulating fluidized bed gasification furnace and realize harmless treatment of fly ash; in the treatment device and the method, the coal gas produced by the system is utilized to ensure the occurrence of melting and combustion or gasification reaction in the melting furnace, thereby simplifying the structure of the fly ash melting furnace, ensuring that the whole system is more stable and the operation is simpler; in addition, the treatment device and the treatment method reduce the occupied area of the whole fly ash melting furnace, reduce the initial investment of a system and improve the economy.
Drawings
FIG. 1 is a schematic view of a circulating fluidized bed gasification and fly ash fusion integrated processing apparatus according to one embodiment of the present invention;
FIG. 2 is a schematic diagram of a tail processing system according to one embodiment of the present invention;
FIG. 3 is a schematic view of a tail processing system according to another embodiment of the present invention; and
FIG. 4 is a schematic view of a circulating fluidized bed gasification and fly ash fusion integrated processing apparatus according to another embodiment of the present invention.
Detailed Description
Exemplary embodiments of the present invention will hereinafter be described in detail with reference to the accompanying drawings, wherein like or similar reference numerals denote like or similar elements. Furthermore, in the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the embodiments of the disclosure. It may be evident, however, that one or more embodiments may be practiced without these specific details. In other instances, well-known structures and devices are shown in schematic form in order to simplify the drawing.
According to the general concept of the present invention, there is provided a circulating fluidized bed gasification and fly ash fusion integrated treatment apparatus including a gasification furnace, a separation device, and a return device forming a circulation loop, the treatment apparatus further including a melting device communicating with the separation device so that a product treated by the separation device can be supplied to the melting device, and communicating with the gasification furnace so that a product treated by the melting device can be supplied to the gasification furnace.
Fig. 1 is a schematic view of a circulating fluidized bed gasification and fly ash melting integrated treatment apparatus according to an embodiment of the present invention, as shown in fig. 1, the circulating fluidized bed gasification and fly ash melting integrated treatment apparatus includes: the gasification furnace comprises a gasification furnace 1, a primary cyclone separator 2 communicated with the top of the gasification furnace, and a material returning device 3 connected with the primary cyclone separator and the gasification furnace; the gasification furnace 1, the primary cyclone separator 2 and the material returning device 3 form a circulation loop to jointly form a circulating fluidized bed gasification reaction device, and the material returning device 3 is suitable for returning the materials collected by the primary cyclone separator 2 to the bottom of the hearth of the gasification furnace 1. The gasification and fly ash melting integrated treatment device of the circulating fluidized bed further comprises: a secondary cyclone separator 4 connected to the primary cyclone separator 2; and the melting device is communicated with the middle part or the upper part of the gasification furnace and comprises a melting furnace 6 and a melting furnace burner 5 connected with the melting furnace, the melting furnace burner 5 is communicated with the bottom of the secondary cyclone separator 4, and the gasified fly ash enters the melting furnace 6 from the melting furnace burner 5.
A slag discharge port and a gasifying agent inlet are arranged at the bottom of the hearth of the gasification furnace; the lower part of the hearth of the gasification furnace is provided with a coal feeding port which is suitable for adding coal into the hearth of the gasification furnace; a melting furnace nozzle is arranged in the middle or at the upper part of the hearth of the gasification furnace and is suitable for introducing high-temperature flue gas G and molten slag H generated by the melting furnace 6 into the gasification furnace 1; the melting furnace burner 5 is provided with a gasification fly ash inlet for receiving gasification fly ash and a first oxidant inlet for introducing a first oxidant B1 into the melting furnace 6; and a second oxidant inlet is formed in the middle of the melting furnace 6, and is suitable for introducing a second oxidant B2 into the melting furnace 6 to organize gasification fly ash combustion so as to generate high-temperature flue gas G and molten slag H in the melting furnace.
Here, the primary cyclone separator 2 and the secondary cyclone separator 4 together form a separating device, a gas outlet of the primary cyclone separator 2 is communicated with an inlet of the secondary cyclone separator 4, a solid material outlet of the primary cyclone separator 2 is communicated with the material returning device 3, a solid material outlet of the secondary cyclone separator 4 is communicated with a gasified fly ash inlet of the melting furnace burner 5, a solid material outlet of the secondary cyclone separator 4 is used for discharging high-temperature gasified fly ash D1, the high-temperature gasified fly ash D1 is introduced into the melting furnace burner 5, and a gas outlet of the secondary cyclone separator 4 is used for discharging high-temperature coal gas F1.
Further, the treatment device further comprises a tail treatment system 7, the tail treatment system 7 comprises an inlet, a fly ash outlet and a product gas outlet, the inlet is used for introducing high-temperature gas F1 separated from the secondary cyclone 4 into the tail treatment system 7, the fly ash outlet is used for discharging low-temperature gasification fly ash D2 from the tail treatment system 7, the low-temperature gasification fly ash D2 is introduced into the melting furnace 6, and the product gas outlet is used for discharging cold gas F. Note that the low-temperature gasification fly ash D2 contains a certain amount of gas. The inlet of the tail treatment system 7 is communicated with the gas outlet of the secondary cyclone 4, and the fly ash outlet is communicated with the melting furnace 6.
Advantageously, a communication duct is provided between the downstream of the gas outlet of the secondary cyclone 4 and the downstream of the solid matter outlet of the secondary cyclone 4 for taking part of the gas discharged from the gas outlet of the secondary cyclone 4 (i.e. the high temperature gas F1) as pneumatic conveying gas to send the first gasified fly ash discharged from the solid matter outlet of the secondary cyclone 4 (i.e. the high temperature gasified fly ash D1) to the melter burner 5. Thus, the high-temperature fly ash from the solid material outlet of the secondary cyclone 4 and the high-temperature coal gas from the gas outlet of the secondary cyclone 4 can be ignited after being mixed in the melting furnace burner 5 and the oxidant introduced through the first oxidant inlet of the melting furnace burner 5, and high-temperature flame is generated. Meanwhile, the low-temperature gasified fly ash D2 discharged from the tail treatment system 7 and the gas contained therein are passed into a high-temperature flame region, thereby realizing the melting combustion or gasification of the fly ash.
Referring to the integrated treatment device for circulating fluidized bed gasification and fly ash melting shown in fig. 1, the invention also provides a corresponding integrated treatment method for circulating fluidized bed gasification and fly ash melting, which adopts the integrated treatment device for circulating fluidized bed gasification and fly ash melting as described above.
In the treatment method, the gasified fly ash and the oxidant are subjected to combustion or gasification reaction in a melting device, the flue gas generated by the melting device and the slag are introduced into the gasification furnace 1, the slag entering the gasification furnace 1 is cooled in the gasification furnace 1 to form granular solid, and the granular solid is discharged from the bottom of the gasification furnace 1. Advantageously, the second gasification fly ash (low-temperature gasification fly ash D2) enters the melting furnace 6 from the side wall surface of the melting furnace 6 near the melting furnace burner 5. Furthermore, the gas conveying the first gasified fly ash as pneumatic conveying gas accounts for 5% -10% of the gas discharged from the gas outlet of the secondary cyclone 4.
The temperature of the gasification furnace 1 is controlled to be maintained between 800 ℃ and 1000 ℃, and the temperature of the melting furnace 6 is controlled to be maintained between 1300 ℃ and 1600 ℃, so that the slag entering the gasification furnace is cooled in the gasification furnace to form granular solid.
Optionally, the gasifying agent A is oxygen, air or water vapor or a mixture of two or three, the first oxidant B1 is oxygen or air or a mixture of two, and/or the second oxidant B2 is oxygen or air or a mixture of two.
Fig. 2 is a schematic diagram of a tail treatment system according to an embodiment of the present invention, and as shown in fig. 2, the tail treatment system 7 includes an air preheater 71, a waste heat boiler 72, a dust separator 73, and a gas cooler 74, the air preheater 71, the waste heat boiler 72, the dust separator 73, and the gas cooler 74 are sequentially communicated, an inlet of the tail treatment system 7 is communicated with the air preheater 71, a product gas outlet of the tail treatment system 7 is communicated with the gas cooler 74, and a fly ash outlet of the tail treatment system 7 is communicated with the dust separator 73. Advantageously, a communication duct is provided between the connection passage between the dust collector 73 and the gas cooler 74 and the connection passage between the dust collector 73 and the fly ash outlet for supplying part of the gas discharged from the dust collector 73 as pneumatic conveying gas to send the second gasified fly ash discharged from the dust collector 73 to the melting furnace 6. Here, the gas conveying the second gasified fly ash as the pneumatic conveying gas accounts for 3% to 5% of the gas discharged from the dust collector 73.
According to a preferred embodiment of the present invention, the gasifying agent a introduced into the gasification furnace 1, the first oxidizing agent B1 introduced into the melting furnace burner 5, and the second oxidizing agent B2 introduced into the melting furnace 6 are all or partially preheated by an air preheater 71 or a waste heat boiler 72 provided in the tail treatment system 7 and then introduced into the melting apparatus.
The operation of the circulating fluidized bed gasification and fly ash melting integrated treatment method will be described below with reference to the circulating fluidized bed gasification and fly ash melting integrated treatment apparatus of fig. 1 and the tail treatment system of fig. 2:
firstly, a gasifying agent A is introduced into the gasification furnace from the bottom or the bottom and the side part of the gasification furnace and performs gasification reaction with coal C to generate a mixture of high-temperature coal gas and coal coke; high-temperature coal gas generated in the gasification furnace enters a primary cyclone separator 2 along with coal coke, under the separation action of the primary cyclone separator 2, most of materials which are not completely gasified are captured, and are sent back to the bottom of the gasification furnace through a material returning device 3, are fully mixed with coal C and a gasifying agent A which are newly added into the gasification furnace, continue to participate in gasification reaction, and the other part of fly ash which is not completely gasified and coal gas enter a secondary cyclone separator 4 together;
the high-temperature gasification fly ash D1 trapped by the secondary cyclone separator 4 is discharged from the secondary cyclone separator, and the high-temperature coal gas F1 is discharged from the top of the secondary cyclone separator 4 and enters the tail treatment system 7;
leading out a part of gas from the high-temperature coal gas F1 as pneumatic conveying gas, and conveying the high-temperature gasification fly ash D1 to a melting furnace burner 5; the high-temperature gasification fly ash D1 and the oxidant B1 enter the melting furnace 6 under the structure of the melting furnace burner 5 to generate combustion or gasification reaction;
the gasified fly ash, oxidant, coal gas carrying fly ash and the like in the melting furnace 6 are subjected to combustion or gasification reaction to generate high-temperature flue gas G and molten slag H, the high-temperature flue gas G and the molten slag H enter the hearth of the gasification furnace through a nozzle of the melting furnace arranged in the middle or upper part of the hearth of the gasification furnace, are mixed with coal, gasification agent and the like in the hearth of the gasification furnace to participate in gasification reaction, and the molten slag H is cooled in the gasification furnace to form granular solid which is discharged out of the system from the bottom of the gasification furnace;
low-temperature gas F2 and low-temperature gasification fly ash D2 are obtained by a tail treatment system 7, a part of the low-temperature gas F2 is led out to be used as pneumatic conveying gas of the low-temperature gasification fly ash D2, the low-temperature gasification fly ash D2 is carried and conveyed to a melting furnace 6, enters the melting furnace 6 from the side wall surface of the melting furnace 6 close to a melting furnace burner 5 and participates in combustion or gasification reaction in the melting furnace 6; and cooling the other part of the low-temperature coal gas F2 by the tail treatment system 7 to obtain product coal gas (cold coal gas F).
Advantageously, the high-temperature gas F1 used as the pneumatic conveying gas for conveying the high-temperature gasification fly ash D1 accounts for 5-10% of the total amount of the high-temperature gas F1, and the low-temperature gas F2 used as the pneumatic conveying gas for conveying the low-temperature gasification fly ash D2 accounts for 3-5% of the total amount of the low-temperature gas F2. It should be noted that the second oxidant B2 is introduced into the middle of the melting furnace 6, which is advantageous for promoting the combustion and melting process in the melting furnace.
Therefore, the technical problem is solved by the following technical scheme: the high-temperature gasification fly ash collected by the secondary cyclone separator of the circulating fluidized bed gasification device is conveyed to a melting furnace burner through high-temperature coal gas, and the high-temperature gasification fly ash and the high-temperature coal gas are contacted with an oxidant through the melting furnace burner to generate combustion reaction to form high-temperature flame. Meanwhile, the low-temperature fly ash collected by the dust remover is conveyed to a high-temperature flame area of the melting furnace through low-temperature coal gas, the amount of secondary air (second oxidant) of the melting furnace is adjusted, so that combustion or gasification reaction occurs in the melting furnace, and the temperature of the melting furnace is controlled between 1300 ℃ and 1600 ℃. High-temperature flue gas/coal gas generated by the melting furnace is introduced into the gasification furnace from the middle part or the upper part of the circulating fluidized bed gasification furnace.
Specifically, coal C is put into a gasification furnace 1 for gasification reaction, the temperature of a hearth is controlled to be between 800 and 1000 ℃, after high-temperature coal gas generated by the gasification reaction is separated by a primary cyclone separator 2, most of materials which are not completely gasified are returned to the gasification furnace 1 for continuous gasification through a material returning device, the gasification fly ash which cannot be collected by the rest primary cyclone separator 2 enters a secondary cyclone separator 4 along with the high-temperature coal gas for further gas-solid separation, and solid materials separated by the secondary cyclone separator 4 are high-temperature gasification fly ash D1. The high-temperature gasification fly ash D1 is discharged from the bottom of the secondary cyclone separator 4, the temperature of the high-temperature gasification fly ash D1 is 850-. 5% -10% of high-temperature coal gas F1 is led out as gas required by pneumatic transmission and is used for transmitting the high-temperature gasification fly ash D1 separated from the secondary cyclone separator 4 to the melting furnace burner 5, and the part of high-temperature coal gas F1 can provide enough heat for the melting process in the melting furnace 6 after entering the melting furnace 6. And treating the rest 90-95% of the high-temperature coal gas F1 by using a tail treatment system 7, so that a small amount of fly ash contained in the high-temperature coal gas is further removed to obtain cold coal gas F.
The tail processing system, not shown in fig. 1, may comprise: the air preheater 71 is used for further recycling the heat in the high-temperature coal gas so as to reduce the energy consumption of the system; the waste heat boiler 72 is used for recycling heat in the high-temperature coal gas; the dust remover 73 further removes the fly ash in the gas, so that the dust content of the cold gas reaches the production standard, and the fly ash collected by the dust remover is low-temperature gasification fly ash D2; a gas cooler 74 cools the gas to a cold gas temperature.
The fly ash captured by the dust collector corresponds to the low-temperature gasification fly ash D2 in the attached figure 1, and can be conveyed into the melting furnace 6 through pneumatic conveying of coal gas, or can be conveyed into the melting furnace 6 together after being merged with the high-temperature gasification fly ash D1, so that near zero emission of the system fly ash can be realized.
In practical application, 90-95% of high-temperature coal gas F1 enters an air preheater and a waste heat boiler to be cooled to obtain coal gas with the temperature of 300-400 ℃, and then enters a dust remover to be further dedusted, and the low-temperature gasification fly ash D2 trapped by the dust remover has the temperature of 300-400 ℃. After the fly ash is collected by a dust collector, low-temperature gas F2 with dust content meeting the gas production standard is obtained, and 3-5% of the low-temperature gas F2 is led out to be used as pneumatic conveying gas of low-temperature gasification fly ash D2. And the rest 95-97 percent of low-temperature coal gas F2 enters a coal gas cooler for cooling, and finally, cold coal gas F is obtained.
The high-temperature gasification fly ash D1 with the temperature of 850-950 ℃ separated by the secondary cyclone separator 4 enters the melting furnace burner 5 through a pipeline under the action of pneumatic transmission of a tiny part of high-temperature coal gas F1 at the outlet of the secondary cyclone separator 4, and is ignited and combusted after being contacted with the first oxidant B1 in the melting furnace burner 5, so that high-temperature flame is formed in the melting furnace 6. Since the high-temperature gas F1 has the characteristics of high heating value and low ignition temperature, it has the functions of igniting and assisting combustion in the ignition process in the melting furnace 6, and the charcoal combustion generates a large amount of heat, thereby easily realizing the combustion and melting of the gasified fly ash and the solid nonflammable fuel in the melting furnace 6.
On the other hand, the low-temperature gasified fly ash D2 separated in the tail treatment system 7 enters the melting furnace 6 from the side wall surface of the melting furnace 6 near the melting furnace burner 5 by the pneumatic conveying action of the gas with high heat value and low ignition point, and is rapidly heated and ignited to participate in the combustion or gasification reaction by contacting with the high-temperature flame formed by the melting furnace burner 5. The temperature in the melting furnace 6 is 1300-1600 ℃. The high-temperature flue gas G and the slag H generated by the melting furnace enter the gasification furnace 1 together, the high-temperature flue gas G contains a large amount of coal gas components and carbon dioxide, and the high-temperature flue gas G enters the middle or middle upper part of the gasification furnace and participates in the gasification furnace reaction, so that the positive influence on improving the material distribution in the gasification furnace 1 and the like is generated, and the gasification reaction in the gasification furnace 1 is promoted. After the slag enters the gasification furnace, because the temperature in the gasification furnace is 800-1000 ℃, and is lower than the melting temperature of the slag, the slag exchanges heat with the materials in the gasification furnace, is cooled into particles in the furnace, falls into the bottom of the gasification furnace 1, and is discharged out of the system together with the gasified bottom slag from the gasification furnace.
In practical application, after the air is preheated by the air preheater in the tail treatment system 7, the preheated air with the temperature of 300-400 ℃ is obtained, and then the method is divided into four parts: 1) the first part and oxygen are mixed to form a gasifying agent A, the gasifying agent A enters from the bottom of the gasification furnace 1 and serves as primary air to provide the gasifying agent required by gasification reaction for the gasification furnace, the oxygen concentration of the gasifying agent A can be 21% -50%, and proper amount of water vapor can also be added to serve as the gasifying agent; 2) the second part enters a material returning device 3 of the gasification furnace to be used as material returning air; 3) the third part is mixed with oxygen to form a first oxidant B1, the first oxidant B1 enters a melting furnace burner 5 and is used as melting furnace burner air, and the oxygen concentration can be 21% -50%; 4) and the fourth part is mixed with oxygen and then enters the melting furnace 6 as a second oxidant B2, and the oxygen concentration can be 21-100% as secondary air of the melting furnace.
The high-temperature coal gas F1 passes through the air preheater 71, the waste heat boiler 72, the dust remover 73 and the coal gas cooler 74 in sequence to become cold coal gas F. Wherein, a part of the low-temperature coal gas F2 from the dust remover 73 is taken out as pneumatic conveying gas for conveying the low-temperature gasification fly ash D2 captured by the dust remover into the melting furnace 6, and the part of the coal gas accounts for 3-5% of the total amount of the low-temperature coal gas F2. To save the system operating cost, the low-temperature gas F2 extracted as pneumatic conveying gas can also be extracted from the outlet of the waste heat boiler 72 and the inlet of the dust remover 73.
Fig. 3 is a schematic diagram of a tail processing system according to another embodiment of the present invention, and the embodiment shown in fig. 3 is different from the embodiment shown in fig. 2 in that: the air preheater 71, the waste heat boiler 72, the gas cooler 74 and the dust remover 73 are communicated in sequence, the inlet of the tail treatment system 7 is communicated with the air preheater 71, the product gas outlet of the tail treatment system 7 is communicated with the dust remover 73, and the fly ash outlet of the tail treatment system 7 is communicated with the dust remover 73. Further, a communication duct for sending a part of the gas discharged from the heat recovery boiler 72 as pneumatic conveying gas to send the second gasified fly ash discharged from the dust collector 73 to the melting furnace 6 is provided between the connection path between the heat recovery boiler 72 and the gas cooler 74 and the connection path between the dust collector 73 and the fly ash outlet. Here, the gas conveying the second gasified fly ash as the pneumatic conveying gas accounts for 3% to 5% of the gas discharged from the waste heat boiler 72.
In the embodiment of fig. 3, the high-temperature coal gas F1 passes through an air preheater 71, a waste heat boiler 72, a coal gas cooler 74 and a dust remover 73 in sequence, and finally the cold coal gas F is obtained. Here, the dust collector 73 may be a bag-type dust collector. The low-temperature gasified fly ash D2 trapped by the dust collector 73 was discharged from the bottom of the dust collector 73 at a temperature of about 100 ℃ to 150 ℃. In contrast to the tail treatment system 7 shown in fig. 2, the low-temperature gas F2 from the waste heat boiler 72 is partially fed into the conveying pipe of the low-temperature gasification fly ash D2 as pneumatic conveying gas, and in an alternative embodiment, the proportion of the low-temperature gas is 3% -5% of the total amount of the low-temperature gas F2.
Fig. 4 is a schematic view of a circulating fluidized bed gasification and fly ash melting integrated treatment apparatus according to another embodiment of the present invention, and the embodiment shown in fig. 4 is different from the embodiment shown in fig. 1 in that: the melting furnace 6 is provided with a slag outlet which is not communicated with the gasification furnace 1, so that the slag H generated by the melting furnace 6 does not enter the gasification furnace 1, the slag H is discharged after being cooled, and only the high-temperature flue gas G generated by the melting furnace 6 enters the gasification furnace 1.
One of the invention points of the invention is that: the high-temperature fly ash and the high-temperature coal gas are mixed with an oxidant in a melting furnace burner and then can be ignited to generate high-temperature flame; then the low-temperature fly ash and coal gas are introduced into a high-temperature flame area, thereby realizing the melting combustion or gasification of the fly ash. In addition, the core contribution points of the invention are as follows: the preheating unit is omitted in the device; the conveying pipeline for mixing the coal gas and the fly ash is arranged, so that the fly ash can be conveyed into the melting furnace and/or the melting furnace burner by the coal gas; in the circulating fluidized bed gasification method, high-temperature fly ash is ignited and melted by utilizing the heat released by high-temperature gas combustion.
The device and the method for integrated treatment of gasification and fly ash fusion of the circulating fluidized bed realize integrated treatment of gasification and fly ash fusion, improve the carbon conversion rate of the circulating fluidized bed gasification furnace and realize harmless treatment of fly ash; in the treatment device and the method, the coal gas produced by the system is utilized to ensure the occurrence of melting and combustion or gasification reaction in the melting furnace, thereby simplifying the structure of the fly ash melting furnace, ensuring that the whole system is more stable and the operation is simpler; in addition, the treatment device and the treatment method reduce the occupied area of the whole fly ash melting furnace, reduce the initial investment of a system and improve the economy.
Although embodiments of the present invention have been shown and described, it would be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention. The scope of applicability of the present invention is defined by the appended claims and their equivalents.
List of reference numerals:
1-gasification furnace
2-first stage cyclone separator
3-material returning device
4-two-stage cyclone separator
5-melting furnace burner
6-melting furnace
7-Tail treatment System
71-air preheater
72 waste heat boiler
73-dust remover
74-gas cooler
A-gasifying agent
B1 first oxidizing agent
B2-second oxidizing agent
C-coal
D1-high temperature gasification fly ash
D2-Low temperature gasification fly ash
E-gasification bottom slag
F-cold gas
F1-high-temperature coal gas
F2-low temp. coal gas
G-high temperature flue gas
H, slag.
Claims (7)
1. The utility model provides a gasification of circulating fluidized bed and flying dust melting integration processing apparatus, includes gasifier (1), separator and returning charge device (3) that form circulation circuit, its characterized in that:
the treatment device further comprises a melting device which is in communication with the separation device such that the product treated by the separation device can be supplied to the melting device, and which is also in communication with the gasification furnace (1) such that the product treated by the melting device can be supplied to the gasification furnace (1);
the melting device consists of a melting furnace burner (5) and a melting furnace (6);
the separation device comprises a primary cyclone separator (2) and a secondary cyclone separator (4), a solid material outlet of the secondary cyclone separator (4) is used for discharging high-temperature gasification fly ash D1, and the high-temperature gasification fly ash D1 is introduced into a melting furnace burner (5); the treatment device also comprises a tail treatment system (7), wherein the tail treatment system (7) comprises an air preheater (71), a waste heat boiler (72), a dust collector (73) and a coal gas cooler (74), low-temperature gasification fly ash D2 is obtained through the tail treatment system (7), and the low-temperature gasification fly ash D2 is introduced into the melting furnace (6);
wherein, the gas outlet of the first-stage cyclone separator (2) is communicated with the inlet of the second-stage cyclone separator (4), the solid material outlet of the first-stage cyclone separator (2) is communicated with the material returning device (3), and the solid material outlet of the second-stage cyclone separator (4) is communicated with the melting device;
a communication pipeline is arranged between the downstream of the gas outlet of the secondary cyclone separator (4) and the downstream of the solid material outlet of the secondary cyclone separator (4) and is used for taking part of gas discharged from the gas outlet of the secondary cyclone separator (4) as pneumatic conveying gas so as to convey first gasified fly ash discharged from the solid material outlet of the secondary cyclone separator (4) to a melting furnace burner (5);
the melting device comprises a first oxidant inlet and a second oxidant inlet, the first oxidant inlet is arranged on a melting furnace burner (5), and the second oxidant inlet is arranged on a melting furnace (6).
2. The integrated circulating fluidized bed gasification and fly ash fusion processing apparatus of claim 1, wherein: the melting furnace burner (5) is communicated with the melting furnace (6), the melting furnace burner (5) is communicated with the separating device, and the melting furnace (6) is communicated with the gasification furnace (1).
3. The integrated circulating fluidized bed gasification and fly ash fusion processing apparatus of claim 1, wherein: the tail treatment system (7) comprises an inlet, a fly ash outlet and a product gas outlet, the inlet of the tail treatment system (7) is communicated with the gas outlet of the secondary cyclone separator (4), and the fly ash outlet is communicated with the melting device.
4. The integrated circulating fluidized bed gasification and fly ash fusion processing apparatus of claim 2, wherein: the melting furnace (6) is provided with a slag outlet which is not communicated with the gasification furnace (1).
5. A method for integrated treatment of circulating fluidized bed gasification and fly ash melting, which comprises using the integrated treatment apparatus of circulating fluidized bed gasification and fly ash melting as claimed in any one of claims 1 to 4.
6. The integrated circulating fluidized bed gasification and fly ash fusion process of claim 5, wherein: the flue gas and the slag generated by the melting device are introduced into the gasification furnace (1).
7. The integrated circulating fluidized bed gasification and fly ash fusion process of claim 5, wherein: the flue gas produced by the melting device is passed into the gasifier (1), and the slag produced by the melting device is discharged from the melting device but not passed into the gasifier (1).
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| CA2881239C (en) * | 2009-01-21 | 2017-02-28 | Res Usa, Llc | System and method for dual fluidized bed gasification |
| US9050574B2 (en) * | 2011-07-27 | 2015-06-09 | Res Usa Llc | Gasification system and method |
| CN106554826B (en) * | 2015-09-30 | 2020-04-07 | 中国科学院工程热物理研究所 | Circulating fluidized bed coal gasification method and device with fine ash fusion |
| CN107043641B (en) * | 2016-02-06 | 2021-01-08 | 中国科学院工程热物理研究所 | Coal gasification method and device of circulating fluidized bed with fine ash return |
| CN107760379A (en) * | 2016-08-23 | 2018-03-06 | 中国石油化工股份有限公司 | Fluid bed and melting bed combined type catalytic coal gasification devices and methods therefor |
| CN107760385B (en) * | 2016-08-23 | 2020-12-01 | 中国石油化工股份有限公司 | Coal gasification device combining fluidized bed and molten bed and method thereof |
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