Method for applying biomass gasified gas to coal-fired boiler

Abstract

The invention discloses a method for applying biomass gasified gas to a coal-fired boiler, and belongs to the technical field of energy utilization, and the method comprises the following steps: 1) biomass raw material pretreatment: selecting a biomass raw material, drying, and crushing; 2) biomass gasification: feeding the pretreated biomass raw material into a gasification furnace, taking air, oxygen or mixed gas of water vapor and air as a gasification agent, and controlling gasification temperature and pressure to carry out gasification reaction to generate biomass gasified gas; (3) purifying and tempering the gasified gas: removing dust particles in the gasified gas by adopting a multi-stage filtering device to reduce the dust content, and removing tar through a tar cracking device or a condensation separation device; according to the method for applying the biomass gasified gas to the coal-fired boiler, biomass energy and the coal-fired boiler can be effectively combined, the emission of pollutants is remarkably reduced while the comprehensive utilization efficiency of energy is improved, and the method has good application prospects and environmental benefits.

Description

Technical Field

[0001] The invention belongs to the technical field of energy utilization, and in particular relates to a method for applying biomass gasification gas to a coal-fired boiler. Background Art

[0002] Biomass energy, as a renewable, low-carbon energy form, has received widespread attention. At the same time, coal-fired boilers still occupy an important position in industrial production and central heating, but the large amount of pollutants generated by coal burning has brought great pressure to the environment. Summary of the invention

[0003] The purpose of the present invention is to solve the above-mentioned problems and to propose a method for applying biomass gasification gas to a coal-fired boiler.

[0004] In order to achieve the above object, the present invention adopts the following technical solution: a method for applying biomass gasification gas to a coal-fired boiler, comprising the following steps:

[0005] 1) Pretreatment of biomass raw materials: Select biomass raw materials for drying and crushing;

[0006] 2) Biomass gasification: The pretreated biomass raw materials are fed into a gasifier, and air, oxygen or a mixture of water vapor and air is used as a gasifying agent. The gasification temperature and pressure are controlled to perform a gasification reaction to generate biomass gasification gas;

[0007] 3) Gasification gas purification and conditioning: Use a multi-stage filtration device to remove dust particles in the gasification gas to reduce the dust content, remove tar through a tar cracking device or a condensation separation device, and use a desulfurization device to remove sulfur-containing compounds such as hydrogen sulfide. Then, according to the combustion characteristics and actual operating conditions of the coal-fired boiler, the purified biomass gasification gas is conditioned and its calorific value, gas composition ratio and other parameters are adjusted to make the calorific value of the gasification gas reach the preset value;

[0008] 4) Co-combustion of gasification gas and coal: The conditioned biomass gasification gas is transported to the furnace of the coal-fired boiler through a specially designed air intake pipe, evenly distributed and fully mixed with the coal. The ratio of gasification gas to coal is reasonably adjusted according to the load demand, combustion conditions and supply of biomass gasification gas of the boiler. By optimizing the structure and operating parameters of the burner, efficient and clean co-combustion is achieved, and the furnace temperature, pressure, flue gas composition and other parameters of the boiler are monitored and controlled in real time;

[0009] 5) Flue gas treatment and emission: The flue gas generated by combustion is subjected to denitrification, dust removal and desulfurization treatment by a conventional flue gas treatment system so that it meets the relevant national emission standards before being discharged into the atmosphere.

[0010] As a further description of the above technical solution:

[0011] The biomass raw materials include one or more of crop straw, wood chips, and forestry waste.

[0012] As a further description of the above technical solution:

[0013] The gasifier is a fixed bed gasifier or a fluidized bed gasifier.

[0014] As a further description of the above technical solution:

[0015] The multi-stage filtering device includes one or more combinations of bag filter, cyclone filter and ceramic filter.

[0016] As a further description of the above technical solution:

[0017] The desulfurization device is a wet desulfurization tower, a dry desulfurization agent or other conventional desulfurization equipment.

[0018] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0019] In the present invention, the method of applying biomass gasification gas to coal-fired boilers can effectively combine biomass energy with coal-fired boilers, while improving the comprehensive utilization efficiency of energy, significantly reducing pollutant emissions, and has good application prospects and environmental benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The present invention is a flow chart of a method for applying biomass gasification gas to a coal-fired boiler. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, rather than all the embodiments. The components of the embodiment of the present invention described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiment of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but only represents the selected embodiment of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. It should be noted that similar numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings. In the description of the embodiments of the present invention, it should be noted that the terms "upper", "inside", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the invented product is usually placed when in use, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In the description of the present invention, it should also be noted that, unless otherwise clearly specified and limited, the terms "set", "install", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be the internal connection of two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0022] Embodiment 1:

[0023] 1) Select corn stalks as biomass raw materials, dry them in the sun until the moisture content is less than 15%, and then use a grinder to grind them into particles with a diameter of 3-5 mm;

[0024] 2) The crushed corn stalks are sent to the fixed bed gasifier, and air is used as the gasification agent. The gasification temperature is controlled at 700-800℃ and the pressure is normal pressure. The generated biomass gasification gas is successively passed through the bag filter to remove dust, the electric tar collector to remove tar, and the wet desulfurization tower to carry out desulfurization treatment. Then, the calorific value is adjusted to 8-10MJ / m by adding an appropriate amount of air. 3 ;

[0025] 3) The quenched and tempered gasified gas is uniformly sprayed into the furnace through multiple air inlet nozzles arranged at the bottom of the furnace of the coal-fired boiler, and is synergistically burned with the burning coal in a volume ratio of 1:3;

[0026] 4) During the combustion process, the burner parameters and gasification gas supply are adjusted in real time according to the boiler load and combustion conditions to stabilize the furnace temperature at 1000-1200℃;

[0027] 5) The flue gas produced by combustion is treated by a selective catalytic reduction denitrification device, a bag filter and a limestone-gypsum wet desulfurization tower before meeting emission standards.

[0028] Embodiment 2:

[0029] 1) Using sawdust as biomass raw material, drying it to reduce its moisture content to about 10%, and crushing it to a particle size of 2-4 mm;

[0030] 2) Send the wood chips into the fluidized bed gasifier, use a mixture of water vapor and air (the volume ratio of water vapor to air is 1:2) as the gasification agent, the gasification temperature is controlled at 800-900℃, the pressure is 0.1-0.2Mpa, the biomass gasification gas is dedusted by a cyclone dust collector and a ceramic filter, the tar is removed by thermal cracking, and then desulfurized by a dry desulfurizer. Add oxygen-enriched air to the purified gasification gas for conditioning, so that its calorific value reaches 10-12MJ / m 3 ;

[0031] 3) The gasified gas is sprayed into the furnace through a swirl burner installed on the side of the furnace of the coal-fired boiler, and burns in coordination with the coal at a volume ratio of 1:4;

[0032] 4) During the combustion process, the swirl intensity and secondary air volume of the swirl burner are adjusted to ensure the stability of the combustion flame and the combustion efficiency;

[0033] 5) The flue gas treatment process is the same as in Example 1, and finally the emission reaches the standard.

[0034] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for applying biomass gasification gas to a coal-fired boiler, characterized in that: The steps include: 1) Pretreatment of biomass raw materials: Select biomass raw materials for drying and crushing; 2) Biomass gasification: The pretreated biomass raw materials are fed into a gasifier, and air, oxygen or a mixture of water vapor and air is used as a gasifying agent. The gasification temperature and pressure are controlled to perform a gasification reaction to generate biomass gasification gas; 3) Gasification gas purification and conditioning: Use a multi-stage filtration device to remove dust particles in the gasification gas to reduce the dust content, remove tar through a tar cracking device or a condensation separation device, and use a desulfurization device to remove sulfur-containing compounds such as hydrogen sulfide. Then, according to the combustion characteristics and actual operating conditions of the coal-fired boiler, the purified biomass gasification gas is conditioned and its calorific value, gas composition ratio and other parameters are adjusted to make the calorific value of the gasification gas reach the preset value; 4) Co-combustion of gasification gas and coal: The conditioned biomass gasification gas is transported to the furnace of the coal-fired boiler through a specially designed air intake pipe, evenly distributed and fully mixed with the coal. The ratio of gasification gas to coal is reasonably adjusted according to the load demand, combustion conditions and supply of biomass gasification gas of the boiler. By optimizing the structure and operating parameters of the burner, efficient and clean co-combustion is achieved, and the furnace temperature, pressure, flue gas composition and other parameters of the boiler are monitored and controlled in real time; 5) Flue gas treatment and emission: The flue gas generated by combustion is subjected to denitrification, dust removal and desulfurization treatment by a conventional flue gas treatment system so that it meets the relevant national emission standards before being discharged into the atmosphere.

2. The method of applying biomass gasification gas to a coal-fired boiler according to claim 1, characterized in that: The biomass raw materials include one or more of crop straw, wood chips, and forestry waste.

3. The method of applying biomass gasification gas to a coal-fired boiler according to claim 1, characterized in that: The gasifier is a fixed bed gasifier or a fluidized bed gasifier.

4. The method of applying biomass gasification gas to a coal-fired boiler according to claim 1, characterized in that: The multi-stage filtering device includes one or more combinations of bag filter, cyclone filter and ceramic filter.

5. The method of applying biomass gasification gas to a coal-fired boiler according to claim 1, characterized in that: The desulfurization device is a wet desulfurization tower, a dry desulfurization agent or other conventional desulfurization equipment.

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