A system and method for coupling ash and slag utilization of biomass furnace and pulverized coal boiler

Abstract

The present invention discloses a slag coupling utilization system and method for a biomass furnace and a pulverized coal boiler, the system comprising: a biomass furnace slag storage bin for collecting slag from the biomass furnace; a first slag grinder for grinding the slag collected from the biomass furnace slag storage bin; a pulverized coal slag storage bin for collecting slag from the pulverized coal boiler; a second slag grinder for grinding the slag collected from the pulverized coal slag storage bin; a pulverized coal slag conveying device for conveying the slag ground by the second slag grinder into the biomass furnace; a pulverized coal ash bin for collecting ash from the pulverized coal boiler; a first ash pump for conveying the ash collected from the pulverized coal ash bin into the biomass furnace; wherein, the system further comprises: a second ash pump or a biomass furnace slag conveying device for conveying the slag ground by the first slag grinder into the pulverized coal boiler. The system and method of the present invention can achieve volume reduction and quantity reduction of biomass slag, and can also alleviate the slagging problem of biomass boilers.

Description

Technical Field

[0001] The invention belongs to the technical field of solid fuel combustion and environmental pollution emission, and in particular relates to a slag coupling utilization system and method of a biomass furnace and a pulverized coal boiler. Background Art

[0002] Fossil energy will eventually run out, and the development of renewable energy will help alleviate energy demand and achieve sustainable development. Biomass is a high-quality renewable energy that can achieve zero CO2 emissions; in addition, biomass energy resources are abundant and have great development potential. Direct combustion power generation is a mature and efficient way to utilize biomass energy. Currently, the main combustion methods are biomass furnaces and fluidized bed combustion. Due to the mature technology and high market share of biomass furnaces, they have been widely used.

[0003] The residual products after biomass combustion are slag and fly ash. Slag and fly ash contain alkali metals, chlorides, heavy metals (Co, Pb, Cr, etc.) and organic toxic substances (polycyclic aromatic hydrocarbons, dioxins, etc.), which are a kind of solid waste. The comprehensive treatment of biomass ash and slag is a major challenge facing biomass combustion at present. Taking a 30MW unit as an example, a unit consumes about 800t / d of fuel per day, the measured ash and slag rate is 9% to 14%, and the annual ash and slag production is about 26,000 to 41,000 tons. The output of solid waste generated by biomass furnaces is huge. The main treatment method at present is landfill, which not only occupies a large area of ​​land, but also pollutes the environment. The carbon content of fly ash is 1% to 2%, and the carbon content of slag is 5% to 10%. Direct landfill also causes a waste of energy.

[0004] Furthermore, the high alkali metal content in biomass also causes corrosion and slagging problems in biomass boilers.

[0005] Based on the above analysis, there is an urgent need for a system and method that can achieve large-scale volume and amount reduction of biomass ash. Summary of the invention

[0006] The purpose of the present invention is to provide a system and method for coupling the ash and slag of a biomass furnace and a pulverized coal boiler to solve one or more of the above-mentioned technical problems. The system and method of the present invention can reduce the volume and amount of biomass ash and slag, and at the same time alleviate the slagging problem of biomass boilers.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] The ash and slag coupling utilization system of a biomass furnace and a pulverized coal boiler of the present invention comprises:

[0009] A biomass furnace ash storage bin is used to collect ash from the biomass furnace;

[0010] a first slag grinding machine, used for grinding the ash collected in the biomass furnace ash storage bin;

[0011] Pulverized coal slag storage bin, used to collect slag from pulverized coal boilers;

[0012] a second slag grinding machine, used for grinding the slag collected in the pulverized coal slag storage bin;

[0013] Pulverized coal slag conveying equipment, used for conveying the slag ground by the second slag grinder into the biomass furnace;

[0014] Pulverized coal ash bin, used to collect ash from pulverized coal boilers;

[0015] a first ash pump, used to deliver the ash collected in the pulverized coal ash bin into the biomass furnace;

[0016] It also includes: a second ash pump or biomass furnace ash conveying equipment, which is used to deliver the ash ground by the first slag grinder into the pulverized coal boiler.

[0017] A further improvement of the present invention is that the mass of ash produced by the biomass furnace fed into the pulverized coal boiler is less than 10% of the mass of ash produced by the pulverized coal boiler.

[0018] A further improvement of the present invention is that the mass of the pulverized coal boiler slag fed into the biomass furnace is less than 10% of the mass of the biomass feedstock.

[0019] A further improvement of the present invention is that the pulverized coal boiler ash is sprayed above the furnace arch of the biomass furnace; the mass of the pulverized coal boiler ash fed into the furnace of the biomass furnace is less than 1% of the mass of the biomass feed to the biomass furnace.

[0020] A further improvement of the present invention is that when the ash ground by the first slag grinder is sent to the pulverized coal boiler by the second ash pump, it is sprayed into the pulverized coal boiler from between the main combustion zone and the SOFA air through the recycled flue gas.

[0021] A further improvement of the present invention is that when the ash ground by the first slag grinder is sent to the pulverized coal boiler by the biomass furnace ash conveying equipment, the ground ash is mixed with the pulverized coal.

[0022] A further improvement of the present invention is that it also includes:

[0023] Biomass feeding equipment, used to feed the biomass furnace;

[0024] A biomass furnace tail gas treatment device, used to treat the tail gas of the biomass furnace;

[0025] Coal feeding equipment, used to feed pulverized coal boilers;

[0026] The fuel pretreatment device is used to mix and pretreat the biomass furnace ash slag conveying equipment and the coal powder; the pretreatment includes: mixing the biomass furnace slag and the coal powder evenly, and grinding them to the particle size preset by the coal powder furnace;

[0027] The pulverized coal boiler tail gas treatment device is used to treat the tail gas of the pulverized coal boiler.

[0028] A method for coupled utilization of ash and slag of a biomass furnace and a pulverized coal boiler of the present invention comprises the following steps:

[0029] collecting ash from the biomass furnace, grinding the collected ash; and sending the ground ash into a pulverized coal boiler for combustion;

[0030] Collecting slag from pulverized coal boilers and grinding the collected slag; collecting ash from pulverized coal boilers;

[0031] The ground slag, pulverized coal boiler ash and biomass are fed into the biomass furnace for combustion;

[0032] When the ground ash is fed into the pulverized coal boiler, it is sprayed into the pulverized coal boiler from between the main combustion zone and the SOFA air through the recycled flue gas; or, the ground ash is mixed with pulverized coal.

[0033] A further improvement of the present invention is that the mass of ash produced by the biomass furnace fed into the pulverized coal boiler is less than 10% of the mass of ash produced by the pulverized coal boiler.

[0034] A further improvement of the present invention is that the mass of the pulverized coal boiler slag fed into the biomass furnace is less than 10% of the mass of the biomass feedstock.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] The present invention can effectively treat the ash of the biomass boiler through the coupled combustion of the biomass furnace and the pulverized coal furnace. The carbon content of the biomass ash after combustion in the pulverized coal furnace is reduced, and the loss on ignition is reduced, so it can be directly used in the construction industry and concrete, which expands the application scope of the biomass ash, recovers the calorific value of the biomass boiler ash, and has excellent economy and environmental protection. In addition, the blending of the biomass boiler ash has little effect on the combustion performance of the pulverized coal furnace and will not cause great disturbance to the system.

[0037] In the present invention, the ash produced by the pulverized coal furnace enters the biomass furnace for secondary combustion, and the residual carbon in the ash produced by the pulverized coal furnace can be further utilized to achieve heat recovery.

[0038] In the present invention, the fly ash of the pulverized coal furnace is sprayed into the biomass furnace, which can capture the alkali metals produced after the biomass is burned, and helps to alleviate the coking problem of the biomass furnace.

[0039] In the present invention, when the fly ash produced by the biomass furnace is sprayed into the pulverized coal furnace as a reburning fuel, the biomass ash contains residual carbon and is rich in K element, which can catalyze the reduction reaction of NOx and also help reduce the NOx emission of the pulverized coal furnace.

[0040] The method of the present invention combines the characteristics of high carbon content of biomass ash and high combustion efficiency of pulverized coal furnace, high unburned carbon content of pulverized coal furnace slag and characteristics of biomass furnace, high alkali metal content of biomass and high silicon and aluminum content in pulverized coal furnace ash, high NOx emission of pulverized coal furnace and high alkali metal and unburned carbon content of biomass ash, and through the coupled combustion of ash, the coking of biomass furnace is alleviated, the NOx emission of pulverized coal furnace is reduced, and the residual carbon in biomass ash and pulverized coal furnace slag is utilized. The present invention achieves the above multiple effects through solid waste such as ash, and has the significant advantage of strong economy. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art; obviously, the drawings described below are some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0042] Figure 1 It is a structural schematic diagram of an ash-slag coupling utilization system of a biomass furnace and a pulverized coal boiler according to an embodiment of the present invention;

[0043] Figure 2 It is a schematic flow chart of a method for coupling ash and slag utilization of a biomass furnace and a pulverized coal boiler according to an embodiment of the present invention;

[0044] Figure 1 to Figure 2 Among them, 1. biomass feeding equipment; 2. pulverized coal slag conveying equipment; 3. biomass furnace ash slag storage bin; 4. first slag grinding machine; 5. biomass furnace; 6. biomass furnace tail gas treatment device; 7. first ash pump; 8. second ash pump; 9. pulverized coal boiler; 10. biomass furnace ash slag conveying equipment; 11. fuel pretreatment device; 12. coal feeding equipment; 13. second slag grinding machine; 14. pulverized coal slag storage bin; 15. pulverized coal furnace ash bin; 16. pulverized coal furnace tail gas treatment device. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical effect and technical solution of the embodiment of the present invention clearer, the technical solution in the embodiment of the present invention is clearly and completely described below in conjunction with the drawings in the embodiment of the present invention; it is obvious that the described embodiment is a part of the embodiment of the present invention. Based on the embodiment disclosed in the present invention, other embodiments obtained by ordinary technicians in this field without making creative work should all fall within the scope of protection of the present invention.

[0046] See also Figure 1 The ash coupling utilization system of a biomass furnace and a pulverized coal boiler according to an embodiment of the present invention comprises: a biomass furnace 5, a pulverized coal boiler 9, a biomass feeding device 1, a pulverized coal slag conveying device 2, a biomass furnace ash storage bin 3, a first slag grinder 4, a second slag grinder 13, a biomass furnace ash conveying device 10, a biomass furnace tail gas treatment device 6, a first ash pump 7, a second ash pump 8, a pulverized coal furnace fuel pretreatment device 11, a coal feeding device 12, a pulverized coal slag storage bin 14, a pulverized coal furnace ash bin 15 and a pulverized coal furnace tail gas treatment device 16.

[0047] In the embodiment of the present invention, the biomass feeding equipment 1 and the pulverized coal furnace slag conveying equipment 2 are connected to the biomass furnace 5; the biomass furnace 5 is connected to the biomass furnace exhaust gas treatment device 6; the biomass furnace ash storage bin 3 is connected to the first slag grinder 4; the first slag grinder 4 is connected to the biomass furnace ash conveying equipment 10, the pulverized coal furnace fuel pretreatment device 11, and the pulverized coal boiler 9.

[0048] In the embodiment of the present invention, the first slag grinding machine 4 may also be connected to the second ash pump 8 and the pulverized coal boiler 9 in sequence.

[0049] In the embodiment of the present invention, the coal feeding equipment 12 is connected to the pulverized coal furnace fuel pretreatment device 11 and the pulverized coal boiler 9; the pulverized coal slag storage bin 14 is connected to the second slag grinder 13 and the pulverized coal slag conveying equipment 2 in sequence.

[0050] In the embodiment of the present invention, the pulverized coal boiler 9 is connected to the pulverized coal furnace tail gas treatment device 16; the pulverized coal furnace ash bin 15 is connected to the first ash pump 7 and the biomass furnace 5 in sequence.

[0051] In the embodiment of the present invention, the mass of ash produced by the biomass furnace and sent to the pulverized coal boiler does not exceed 10% of the ash output of the pulverized coal boiler.

[0052] In the embodiment of the present invention, the mass of the slag produced by the pulverized coal boiler and fed into the biomass furnace does not exceed 10% of the biomass feed amount.

[0053] In the embodiment of the present invention, fly ash from the pulverized coal furnace is sprayed above the furnace arch of the biomass furnace, and the mass of the fly ash sent into the furnace does not exceed 1% of the biomass feed amount of the biomass furnace.

[0054] In the embodiment of the present invention, the ash produced by the biomass furnace can be ground and mixed with coal powder, or sprayed into the coal powder furnace from between the main combustion zone and the SOFA wind through the recycled flue gas.

[0055] In the system of the embodiment of the present invention, the ash produced by the biomass furnace is conveyed into the pulverized coal furnace for combustion through a coal conveyor belt, and can also be brought into the pulverized coal furnace through recycled flue gas. The slag produced by the pulverized coal furnace is conveyed to the biomass furnace for combustion, and part of the fly ash produced by the pulverized coal furnace is sprayed into the biomass furnace.

[0056] The principle of the system of the embodiment of the present invention is: the output of biomass furnace ash is large, and it is difficult to be used in the building materials industry. The general treatment method is landfill treatment. Since the ash contains heavy metals and organic toxic substances, it will cause environmental pollution and occupy a large amount of land. The ash has a high carbon content. If it is directly landfilled, the residual heat will be wasted. Therefore, it is urgent to treat the biomass ash comprehensively, environmentally friendly and economically. The combustion method can realize the heat recovery and volume reduction treatment of biomass furnace ash. The ash loss after combustion is further reduced, and it can be used in the building materials industry. This method is economical and environmentally friendly, and can realize large-scale treatment of ash. Therefore, the biomass ash can be mixed with coal powder for combustion to realize the combustion of ash and utilize its residual heat. At the same time, the slag of the pulverized coal boiler will also have residual carbon. The ash of the pulverized coal boiler is sent to the biomass furnace and mixed with biomass for combustion, and the heat of the residual carbon of the biomass furnace ash is further utilized. Through the coupled combustion of the biomass furnace and the pulverized coal furnace ash, the volume reduction and heat recovery of the ash are achieved.

[0057] In addition, when coupled, the high content of alkali metals and residual carbon in biomass ash will help catalyze the reduction of NOx in the pulverized coal furnace and reduce NOx emissions. Therefore, a part of the biomass ash is ground and sprayed between the main combustion zone and the SOFA wind of the pulverized coal furnace. In addition, the fly ash of the pulverized coal furnace is sprayed above the furnace arch of the biomass furnace. Due to the high silicon-aluminum ratio of the fly ash, it will help capture the alkali metals in the biomass furnace, thereby alleviating the slagging of the biomass furnace.

[0058] The working process of the system described in the embodiment of the present invention is as follows: the biomass transported by the biomass feeding equipment 1 and the slag transported by the pulverized coal slag conveying equipment 2 enter the biomass furnace 5 at the same time; the ash and slag produced by the biomass furnace 5 enter the biomass furnace ash and slag storage bin 3, and are ground by the first slag grinder 4 and pretreated in the pulverized coal furnace fuel pretreatment device 11 together with the pulverized coal transported by the coal feeding equipment 12, and can also be transported by the second ash pump 8 and sprayed into the pulverized coal boiler 9 between the main combustion zone and the SOFA wind with the recycled flue gas; part of the ash produced by the pulverized coal boiler 9 is sprayed from above the furnace arch of the biomass furnace 5 through the first ash pump 7; part of the slag produced by the pulverized coal boiler 9 is ground by the second slag grinder 13 and then sent to the biomass furnace 5 through the pulverized coal slag conveying equipment.

[0059] See also Figure 2 A method for utilizing the ash coupling utilization system of a biomass furnace and a pulverized coal boiler according to an embodiment of the present invention specifically comprises the following steps:

[0060] The biomass transported by the biomass feeding equipment and the slag transported by the pulverized coal slag transporting equipment enter the biomass furnace at the same time; the ash and slag produced by the biomass furnace enter the ash and slag storage bin of the biomass furnace, are ground by the first slag grinder, and are pre-treated in the pulverized coal furnace fuel pre-treatment device together with the pulverized coal transported by the coal feeding equipment, and then enter the pulverized coal furnace for combustion; part of the ash produced by the pulverized coal furnace is sprayed into the biomass furnace arch from above through the first ash pump; the ash produced by the biomass furnace can also be sprayed into the pulverized coal furnace through the second ash pump after passing through the first slag grinder.

[0061] The biomass furnace described in the present invention includes all boilers for burning biomass including biomass grate furnace and circulating fluidized bed.

[0062] The utilization system or method of the embodiment of the present invention, through the coupling of the biomass furnace and the pulverized coal boiler, on the one hand, effectively treats the ash of the biomass boiler. The carbon content of the biomass ash after combustion in the pulverized coal boiler is reduced, and the loss on ignition is reduced. It can be directly used in the construction industry and concrete, further expanding the application scope of the biomass ash. At the same time, the calorific value of the biomass boiler ash is further recovered, and it is excellent in economy and environmental protection. On the other hand, the blending of the biomass boiler ash has little effect on the combustion performance of the pulverized coal furnace and will not cause a large disturbance to the system. The ash produced by the pulverized coal furnace enters the biomass furnace for secondary combustion, and the residual carbon in the ash produced by the pulverized coal furnace can be further utilized to achieve heat recovery. The fly ash of the pulverized coal furnace is sprayed into the biomass furnace, which can capture the alkali metals produced after the biomass is burned, which helps to alleviate the coking problem of the biomass furnace. The slag from the pulverized coal furnace can be mixed with biomass for reuse. When the fly ash produced by the biomass furnace is sprayed into the pulverized coal furnace as a reburning fuel, the biomass ash contains residual carbon and is rich in K, which can catalyze the reduction reaction of NOx and help reduce the NOx emissions of the pulverized coal furnace.

[0063] In summary, the present invention discloses a coupled utilization system and method of ash of a biomass furnace and a pulverized coal boiler, the system comprising a biomass furnace, a pulverized coal furnace, a biomass feeding device, a pulverized coal furnace slag conveying device, a biomass furnace ash slag storage bin, a slag grinding machine, a biomass furnace ash slag conveying device, a biomass furnace tail gas treatment device, an ash pump, a pulverized coal furnace, an ash slag conveying device, a pulverized coal furnace fuel pretreatment device, a coal feeding device, a pulverized coal furnace ash slag storage bin, a pulverized coal furnace ash bin, and a pulverized coal furnace tail gas treatment device. The ash produced by the biomass furnace is fed into the pulverized coal furnace for combustion, and at the same time, part of the ash produced by the pulverized coal furnace is fed into the biomass furnace for re-combustion, thereby achieving a reduction in the volume of the ash, utilizing the residual carbon in the ash, further reducing the carbon content and the loss on ignition of the ash after combustion, and can be directly used in industries such as building materials and concrete production, expanding the scope of utilization of biomass ash, and being highly economical and environmentally friendly. Biomass ash is sprayed into the pulverized coal furnace from the main combustion zone of the pulverized coal furnace and the SOFA wind through the recycled flue gas. Due to the high carbon content and alkali metal content in the biomass ash, spraying it into the pulverized coal furnace enhances the NOx reduction effect of the pulverized coal furnace, which is beneficial to reducing NOx emissions; the fly ash of the pulverized coal furnace is sprayed into the biomass furnace, which can also further capture the alkali metals in the biomass furnace, which is beneficial to alleviate the coking problem of the biomass furnace. The ash-slag coupling system is economical and environmentally friendly, and can effectively achieve the volume reduction and reduction of biomass ash.

[0064] The above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. Although the present invention has been described in detail with reference to the above embodiments, a person skilled in the art can still modify or make equivalent substitutions to the specific implementations of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention are within the scope of protection of the claims of the present invention to be approved.

Claims

1. A method for utilizing a coupled ash and slag utilization system of a biomass furnace and a pulverized coal boiler, characterized in that: The ash-slag coupling utilization system of the biomass furnace and the pulverized coal boiler comprises: A biomass furnace ash storage bin (3) for collecting ash from the biomass furnace; A first slag grinding machine (4) is used to grind the ash collected by the biomass furnace ash storage bin (3); A pulverized coal slag storage bin (14) for collecting slag from a pulverized coal boiler; a second slag grinding machine (13), used for grinding the slag collected in the pulverized coal slag storage bin (14); A pulverized coal slag conveying device (2) is used to convey the slag ground by the second slag grinder (13) into the biomass furnace; A pulverized coal ash bin (15) for collecting ash from a pulverized coal boiler; a first ash pump (7) for delivering ash collected in the pulverized coal ash bin (15) into the biomass furnace; a second ash pump (8) or a biomass furnace ash conveying device (10), used for conveying the ash ground by the first slag grinder (4) into the pulverized coal boiler; wherein when the ash ground by the first slag grinder (4) is conveyed into the pulverized coal boiler by the second ash pump (8), the ash is sprayed into the pulverized coal boiler from between the main combustion zone and the SOFA air through the recirculated flue gas; Biomass stoves (5); Pulverized coal boiler (9); A biomass feeding device (1) for feeding the biomass furnace; A biomass furnace tail gas treatment device (6), used for treating tail gas from the biomass furnace; A coal feeding device (12) for feeding the pulverized coal boiler; The fuel pretreatment device (11) is used to pre-treat the biomass furnace ash conveying equipment (10) and the pulverized coal; the pre-treatment comprises: uniformly mixing the biomass furnace ash and the pulverized coal, and grinding them to a particle size preset to the pulverized coal furnace; A pulverized coal boiler tail gas treatment device (16), used for treating tail gas from a pulverized coal boiler; The utilization method of the ash-slag coupling utilization system of the biomass furnace and the pulverized coal boiler comprises the following steps: collecting ash from the biomass furnace, grinding the collected ash; and sending the ground ash into a pulverized coal boiler for combustion; Collecting slag from pulverized coal boilers and grinding the collected slag; collecting ash from pulverized coal boilers; The ground slag, pulverized coal boiler ash and biomass are fed into the biomass furnace for combustion; When the ground ash is fed into the pulverized coal boiler, it is sprayed into the pulverized coal boiler from between the main combustion zone and the SOFA air through the recycled flue gas; or, the ground ash is mixed with pulverized coal.

2. The method for utilizing the ash-slag coupling utilization system of a biomass furnace and a pulverized coal boiler according to claim 1, characterized in that: The ash quality produced by the biomass furnace fed into the pulverized coal boiler is less than 10% of the ash quality produced by the pulverized coal boiler.

3. The method for utilizing the ash-slag coupling utilization system of a biomass furnace and a pulverized coal boiler according to claim 1, characterized in that: The mass of pulverized coal boiler slag fed into the biomass furnace is less than 10% of the mass of the biomass feed.

4. The method for utilizing the ash-slag coupling utilization system of a biomass furnace and a pulverized coal boiler according to claim 1, characterized in that: Pulverized coal boiler ash is sprayed above the furnace arch of the biomass furnace; The mass of pulverized coal boiler ash fed into the biomass furnace is less than 1% of the mass of biomass feed to the biomass furnace.

5. The method for utilizing the ash-slag coupling utilization system of a biomass furnace and a pulverized coal boiler according to claim 1, characterized in that: When the ash ground by the first slag grinder (4) is sent to the pulverized coal boiler through the biomass furnace ash conveying equipment (10), the ground ash is mixed with the pulverized coal and burned.

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