Biocoal preparation unit and biomass blending combustion system

Abstract

The utility model belongs to the field of biomass resource utilization, and particularly discloses a biological coal preparation unit and a biomass blending combustion system.The biological coal preparation unit comprises a water washing module, a dehydration module and a baking module which are sequentially connected in the biomass conveying direction, the flue gas is used for washing the biomass to be treated to remove impurities, and washing slurry is fed into the dehydration module; the dehydration module is used for carrying out solid-liquid separation on the washing slurry and feeding the biomass subjected to impurity removal into the baking module; and the baking module is used for introducing flue gas and heating, so that the flue gas is used for baking the biomass subjected to impurity removal, and then the biological coal is prepared. According to the method, the alkali metal can be prevented from being converted, enriched and remained in the biological coal in the subsequent baking process through water washing, and meanwhile, the physical and chemical characteristics of the biomass can be effectively improved, so that the blending combustion ratio of the biomass is greatly increased.

Description

Technical Field

[0001] This application belongs to the field of biomass resource utilization, and more specifically, relates to a biomass coal preparation unit and a biomass co-firing system. Background Technology

[0002] By the end of 2023, the carbon emissions from my country's coal-fired power industry accounted for approximately 40% of the country's total carbon emissions. From the perspective of carbon emission share, the low-carbon transformation of the coal-fired power industry is a key task under the vision of carbon neutrality. Biomass co-firing is widely considered the most cost-effective and easily deployable way to reduce carbon dioxide emissions from the coal-fired power industry. The main advantages of co-firing are that, compared to other technologies, it can achieve carbon dioxide emission reductions in the coal industry at a very low cost and in a short time. Furthermore, biomass co-firing currently boasts the highest electrical efficiency among biomass conversion technologies.

[0003] Currently, biomass co-firing mainly focuses on two directions. The first is using roasted biomass as a co-combustion fuel. The decomposition of the hemicellulose matrix during roasting brings significant benefits, but current roasting technology is costly and difficult to profit from. The second is direct co-firing, but some inherent defects of biomass restrict its large-scale application, resulting in the current co-firing ratio of biomass being less than 20%, which fails to achieve the effects of energy conservation and emission reduction. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this application provides a biomass coal preparation unit and a biomass co-firing system, aiming to solve the problems of high cost and low co-firing ratio in existing biomass baking.

[0005] According to one aspect of this application, a biomass preparation unit is provided, specifically comprising a washing module, a dewatering module, and a baking module connected sequentially along the biomass transport direction. The washing module is used to introduce biomass to be treated, a liquid solvent, and flue gas to wash and remove impurities from the biomass using the flue gas, and then sends the washed slurry to the dewatering module. The dewatering module is used to perform solid-liquid separation on the washed slurry and then sends the purified biomass to the baking module. The baking module is used to introduce flue gas and heat it to bake the purified biomass using the flue gas, thereby producing biomass.

[0006] Compared with the prior art, the above-described technical solutions conceived in this application can effectively improve the physical and chemical properties of biomass and greatly increase the proportion of biomass co-firing by using flue gas for water washing and baking. It also has the advantages of simple structure and low cost.

[0007] As a further preferred embodiment, the water washing module is provided with a first flue gas inlet, which is used to connect to the outlet of the dust collector to introduce undesulfurized flue gas for water washing and impurity removal.

[0008] As a further preferred embodiment, the baking module is provided with a second flue gas inlet, which is used to connect to the outlet of the dust collector to introduce undesulfurized flue gas for baking.

[0009] As a further preferred embodiment, the water washing module is provided with a first gas outlet, which is used to connect to the desulfurization tower to send the flue gas after the water washing reaction into the desulfurization tower for desulfurization treatment.

[0010] As a further preferred embodiment, the baking module is provided with a second gas outlet, which is used to connect to a boiler to send the energy-carrying gas generated during baking into the boiler for combustion.

[0011] As a further preferred embodiment, the dehydration module may be a centrifugal dehydrator, a vibrating screen, a vacuum dehydrator, a plate and frame filter press, or a pressure filter.

[0012] According to another aspect of this application, a biomass co-firing system is provided, the biomass co-firing system comprising a combustion unit and the aforementioned biomass preparation unit, the combustion unit comprising a coal mill, a boiler, a dust collector and a desulfurization tower connected in sequence, the coal mill being connected to a baking module for grinding the biomass and feeding it into the boiler for co-firing or full combustion; the outlet of the dust collector is also connected to a water washing module and a baking module to send the undesulfurized flue gas after dust removal into the water washing module and the baking module.

[0013] As a further preferred embodiment, the combustion unit also includes a denitrification component, which is disposed between the boiler and the dust collector for denitrification treatment of the flue gas.

[0014] In summary, compared with the prior art, the technical solutions conceived in this application have the following main technical advantages:

[0015] 1. This application utilizes flue gas to wash biomass, which can remove not only water-soluble alkali metals but also some non-water-soluble alkali metals, avoiding the conversion and enrichment of alkali metals in biomass during subsequent roasting, thereby effectively increasing the biomass blending ratio. Simultaneously, this application also utilizes flue gas to roast biomass, which can improve the physical and chemical properties of biomass, further increasing the biomass blending ratio and solving the problem of low biomass blending ratio in existing applications. More importantly, this application uses flue gas as a heat source and reaction atmosphere for washing and roasting biomass, eliminating the need for air separation and heating, effectively reducing roasting costs. Furthermore, in a micro-oxygen environment and in complex atmospheres containing SO2, CO2, and HCl, the roasting temperature and roasting time can be reduced, further lowering roasting costs.

[0016] 2. This application connects the flue gas inlets of the washing module and the baking module to the outlet of the dust collector, so as to use the undesulfurized flue gas after dust removal to wash and bake the biomass. This not only improves the washing and baking effect of biomass by utilizing the undesulfurized flue gas with complex composition, high sulfur content and suitable temperature, but also achieves synergistic desulfurization of flue gas, effectively reducing the load on the power plant desulfurization tower and reducing the use of desulfurizing agents.

[0017] 3. This application also connects the gas outlet of the baking module to the boiler, which can send the energy-carrying gas generated during baking into the boiler for combustion, thereby further improving the energy utilization rate of biomass. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the biomass co-firing system provided in the embodiments of this application.

[0019] In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, wherein:

[0020] 1-Bio-coal preparation unit, 11-water washing module, 111-liquid inlet, 112-first solid inlet, 113-first flue gas inlet, 114-liquid outlet, 115-first gas outlet, 12-dehydration module, 13-baking module, 131-second flue gas inlet, 132-second solid inlet, 133-solid outlet, 134-second gas outlet, 2-combustion unit, 21-coal mill, 22-boiler, 23-denitrification assembly, 24-dust collector, 25-desulfurization tower, 26-chimney. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0022] like Figure 1 As shown, according to one aspect of this application, a biomass coal preparation unit is provided, specifically including a water washing module 11, a dewatering module 12, and a baking module 13 connected sequentially along the biomass transport direction, wherein,

[0023] The washing module 11 is provided with a liquid inlet 111, a first solid inlet 112, a first flue gas inlet 113 and a liquid outlet 114. The liquid inlet 111 and the first solid inlet 112 are used to introduce liquid solvent and biomass to be treated to obtain mixed slurry, respectively. The first flue gas inlet 113 is used to introduce flue gas into the mixed slurry to wash and remove impurities from the biomass to be treated and obtain washed slurry. The liquid outlet 114 is connected to the dewatering module 12 and is used to send the washed slurry into the dewatering module 12.

[0024] Dewatering module 12 is used to perform solid-liquid separation on the water washing slurry and send the purified biomass into baking module 13;

[0025] The baking module 13 is provided with a second flue gas inlet 131, a second solid inlet 132 and a solid outlet 133. The baking module 13 is also provided with a heating component. The second flue gas inlet 131 is used to introduce flue gas, and the second solid inlet 132 is connected to the dehydration module to send the impurity-removed biomass into the baking module 13. Under the action of the heating component, the flue gas is used to bake the impurity-removed biomass to produce bio-coal, which is then discharged from the solid outlet 133.

[0026] This application utilizes flue gas to wash biomass, which not only removes water-soluble alkali metals but also some non-water-soluble alkali metals, preventing their conversion and accumulation during subsequent roasting and their residue in the bio-coal. Simultaneously, this application proposes using undesulfurized flue gas for biomass roasting, which effectively improves the physical and chemical properties of biomass, significantly increasing the biomass blending ratio and solving the problem of low biomass blending ratios in existing processes. More importantly, this application uses flue gas as a heat source and reaction atmosphere for biomass washing and roasting. Compared to existing technologies that use nitrogen as a heat source and reaction atmosphere, this eliminates the need for air separation and heating, effectively reducing roasting costs. Furthermore, in a micro-oxygen environment and under complex atmospheres containing SO2, CO2, and HCl, it can lower the roasting temperature and time, further reducing roasting costs.

[0027] Furthermore, the first flue gas inlet 113 of the washing module 11 and the second flue gas inlet 131 of the baking module 13 are both connected to the outlet of the dust collector 24, so that the undesulfurized flue gas after dust removal is sent into the washing module 11 and the baking module 13. The particulate matter content of the flue gas at the outlet of the dust collector 24 is low, which can avoid affecting the production of bio-coal. Moreover, the flue gas at the outlet of the dust collector 24 has a complex composition, high sulfur content, and suitable temperature, which can effectively improve the washing and baking effect of biomass. At the same time, it can also achieve synergistic desulfurization of flue gas, thereby reducing the load of the desulfurization tower, reducing the use of desulfurizing agent, and further reducing production costs.

[0028] Furthermore, the water washing module 11 is also provided with a first gas outlet 115, which is used to connect to the desulfurization tower 25 so as to send the flue gas that has participated in the water washing reaction into the desulfurization tower 25 for desulfurization treatment, so as to avoid environmental impact.

[0029] Furthermore, the baking module 13 is also provided with a second gas outlet 134, which is used to connect to the inlet of the boiler 22 to send the energy-carrying gas generated during baking into the boiler 22 for combustion, thereby further improving the energy utilization rate of biomass.

[0030] Furthermore, the dewatering module 12 uses a centrifugal dewatering machine, vibrating screen, vacuum dewatering machine, plate and frame filter press or pressure filter, which only needs to perform solid-liquid separation of the washing slurry through physical action to obtain impurity-free biomass, which is convenient for subsequent baking.

[0031] According to another aspect of this application, a biomass co-firing system is provided, which includes a combustion unit 2 and the aforementioned biomass preparation unit 1. The combustion unit 2 includes a coal mill 21, a boiler 22, a dust collector 24, and a desulfurization tower 25 connected in sequence. The coal mill 21 is connected to the solid outlet 133 of the baking module 13 and is used to grind the biomass and feed it into the boiler 22 for co-firing or full-firing. When co-firing, pulverized coal is also fed into the coal mill 21. The boiler 22 sends the flue gas generated by combustion to the dust collector 24 for dust removal treatment. At the same time, the flue gas outlet of the dust collector 24 is also connected to the flue gas inlet of the water washing module 11 and the baking module 13 to send the dust-removed but undesulfurized flue gas into the water washing module 11 and the baking module 13.

[0032] Furthermore, the combustion unit 2 also includes a denitrification component 23 and a chimney 26. The denitrification component 23 is located between the boiler 22 and the dust collector 24 and is used to denitrify the flue gas. The chimney 26 is located after the desulfurization tower 25 and is used to discharge the desulfurized flue gas.

[0033] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A biomass coal preparation unit, characterized in that, The assembly includes a washing module (11), a dewatering module (12), and a baking module (13) connected sequentially along the biomass transport direction. The washing module (11) is used to introduce the biomass to be treated, a liquid solvent, and flue gas to wash and remove impurities from the biomass using the flue gas, and then send the washed slurry to the dewatering module (12). The dewatering module (12) is used to perform solid-liquid separation on the washed slurry and send the removed biomass to the baking module (13). The baking module (13) is used to introduce flue gas and heat it to bake the removed biomass using the flue gas, thereby producing bio-coal.

2. The bio-coal preparation unit as described in claim 1, characterized in that, The water washing module (11) is provided with a first flue gas inlet (113), which is used to connect to the outlet of the dust collector (24) to introduce undesulfurized flue gas for water washing and impurity removal.

3. The bio-coal preparation unit as described in claim 1 or 2, characterized in that, The baking module (13) is provided with a second flue gas inlet (131), which is used to connect to the outlet of the dust collector (24) to introduce undesulfurized flue gas for baking.

4. The bio-coal preparation unit as described in claim 1, characterized in that, The water washing module (11) is provided with a first gas outlet (115), which is used to connect to the desulfurization tower (25) to send the flue gas after water washing reaction into the desulfurization tower (25) for desulfurization treatment.

5. The bio-coal preparation unit as described in claim 1, characterized in that, The baking module (13) is provided with a second gas outlet (134), which is used to connect to the boiler (22) to send the energy-carrying gas generated during baking into the boiler (22) for combustion.

6. The bio-coal preparation unit as described in claim 1, characterized in that, The dehydration module (12) adopts a centrifugal dehydrator, vibrating screen, vacuum dehydrator, plate and frame filter press or pressure filter.

7. A biomass co-firing system, characterized in that, The system includes a combustion unit (2) and a biomass coal preparation unit (1) as described in any one of claims 1 to 6. The combustion unit (2) includes a coal mill (21), a boiler (22), a dust collector (24), and a desulfurization tower (25) connected in sequence. The coal mill (21) is connected to a baking module (13) for grinding the biomass coal and feeding it into the boiler (22) for blending or full combustion. The outlet of the dust collector (24) is also connected to a water washing module (11) and a baking module (13) to send the undesulfurized flue gas after dust removal into the water washing module (11) and the baking module (13).

8. The biomass co-firing system as described in claim 7, characterized in that, The combustion unit (2) also includes a denitrification component (23), which is located between the boiler (22) and the dust collector (24) for denitrifying the flue gas.

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