Biomass fuel rod and production method and application thereof

Abstract

The invention discloses a biomass fuel rod and a production method and application thereof, and belongs to the technical field of biomass fuels, the biomass fuel rod comprises the following components by mass: 60-80 parts of a biomass raw material, 10-20 parts of a binder, 1-5 parts of a combustion improver, 3-8 parts of a sulfur and chlorine fixing agent, 1-3 parts of a denitration agent, and 2-5 parts of an ash content regulator. The production method specifically comprises the following steps: (1) pretreatment: crushing a biomass raw material until the particle size is less than or equal to 2mm, and carrying out pretreatment by adopting baking semi-carbonization; (2) mixing: sequentially adding a binder, a combustion improver, a sulfur-fixing and chlorine-fixing agent, a denitration agent and an ash content regulator which are ground until the particle size is less than or equal to 2mm, and stirring and mixing for 5-10 minutes; (3) forming: carrying out extrusion forming by adopting a twin-screw extruder under the pressure of 15-25MPa and the temperature of 80-100 DEG C to obtain a fuel rod with the density of 1.2-1.4 g / cm < 3 >; the production method is simple and easy to implement, the combustion performance of the produced fuel rod is good, and the combustion efficiency and the environmental protection property are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of fuel, specifically relates to a kind of biomass fuel stick and its production method and application, belongs to biomass fuel technical field. BACKGROUND

[0002] Most of the fuel currently used by people is fossil energy such as coal, oil and natural gas, which is non-renewable energy. It is gradually depleted under large-scale exploitation by humans and emits a large amount of toxic gases into the air when burned, causing serious air pollution. Therefore, humans are looking for renewable clean fuel to replace it.

[0003] Biomass fuel stick refers to various organisms produced by photosynthesis using air, water, land, etc., i.e. all living and growing organic matter, commonly known as biomass. It includes plants, animals and microorganisms. Broad concept: biomass includes all plants, microorganisms and animals that feed on plants and microorganisms and their waste. Representative biomass such as crops, crop waste, wood, wood waste and animal manure. Narrow concept: biomass mainly refers to straw, trees and other lignocellulose (referred to as lignin) during agricultural and forestry production, except for food and fruits, agricultural and forestry waste, and poultry manure and waste during livestock production, etc. Characteristics: renewable, low pollution, widely distributed, a green energy, and a fuel encouraged by national policy, which can replace traditional solid fuel and partially replace traditional liquid and gas fuel, such as coal, oil, etc. Coal-fired boilers, gas-fired boilers and oil-fired boilers can all be replaced with biomass fuel sticks.

[0004] Although existing biomass fuel sticks are renewable energy sources that have attracted attention, they still have some technical and application defects, mainly including the following aspects: low calorific value: the calorific value of biomass fuel (about 14-18 MJ / kg) is much lower than that of coal (24-30 MJ / kg) or oil (42-45 MJ / kg), and more fuel is needed to achieve the same heat output during combustion; High ash content: the ash content of some biomass (such as rice husk and straw) can reach 10%-20%, which can easily cause ash accumulation and slagging in combustion equipment, affecting thermal efficiency; High ash content: the ash content of some biomass (such as rice husk and straw) can reach 10%-20%, which can easily cause ash accumulation and slagging in combustion equipment, affecting thermal efficiency; Strong hygroscopicity: biomass fuel sticks are prone to absorb moisture (especially wood particles), which can cause mold growth or spontaneous combustion risk; Long-term storage loss: if humidity control is not proper, it may rot or heat up, reducing combustion efficiency.

[0005] Patent CN107446643A A kind of high-heat high-strength biomass stick body fuel and its preparation method, its raw material includes rice straw, wheat straw, residual plant of castor bean, fine strip asparagus portion, ai frame wood, bamboo material, waste wood, corn cob, corn stalk, barley stalk, coal powder, dolomite powder, red mud, calcium peroxide, nai intermediate pitch, reinforcing agent, oxygen enhancer, combustion-supporting agent and binder, effectively improve the strength of biomass stick body fuel, and further improve its burn resistance, but it only carries out sulfur fixation, and does not fix chlorine, pollution emission needs to be improved, urea is denitration agent, and the effect of denitration is poor, is easily limited by temperature, and ammonia escape is easy to produce.

[0006] Patent CN107267242B A kind of high net heat value biomass stick body fuel and its preparation method, modification oxygen enhancer, modification combustion-supporting agent, binder and the increase of chemical conditioning agent, effectively improve its combustion performance, make combustion more fully, avoid harmful gas produced by incomplete combustion, can effectively improve the combustion performance of the biomass stick body fuel of the present application, make combustion more fully, but the fuel only increases the heat value from combustion-supporting agent, needs a large amount of combustion-supporting agent, cost increases, the increased heat value is limited, and there is no sulfur fixation and chlorine fixation in preparation process, pollution emission still exists, and environmental performance needs to be improved; Therefore, the heat value and the efficiency and environmental performance of the biomass fuel stick in the prior art still cannot meet the needs in actual use, so it becomes a technical problem to be solved by the person skilled in the art to develop a biomass fuel stick and its production method and application that can overcome the above defects. SUMMARY

[0007] The technical problem to be solved by the present application is to provide a biomass fuel stick and its production method and application, which are simple and easy to implement, and the combustion performance of the produced fuel stick is good, and the combustion efficiency and environmental performance are improved.

[0008] The technical solution of the present application to solve the above technical problems is: A biomass fuel stick, including the following components by mass fraction: biomass raw material: 60-80 parts, binder: 10-20 parts, combustion-supporting agent: 1-5 parts, sulfur and chlorine fixation agent: 3-8 parts, denitration agent: 1-3 parts, ash adjusting agent: 2-5 parts.

[0009] Technical effects, the present application reasonably designs the proportioning between each component of the fuel rod, and ensures that the fuel rod reaches a balance between heat value, combustion efficiency, emission control and anti-slagging performance: the biomass raw material is controlled at 60-80 parts: if the proportion is too high (> 80 parts), the proportion of functional additives is reduced, resulting in high release of nitrogen oxides, sulfur oxides and chlorides during combustion of the fuel rod; if it is too low (< 60 parts), the heat value is reduced and the cost is increased; the binder is controlled at 10-20 parts: if it is too high (> 20 parts), the heat value is diluted and the ash content is increased, and if it is too low (< 10 parts), the molding strength (density 1.2-1.4 g / cm³) cannot be guaranteed; the combustion aid is controlled at 1-5 parts: if it is too high (> 5 parts), it will cause too fast combustion and increase the safety risk; if it is too low (< 1 part), the combustion is insufficient and the combustion rate is reduced; the sulfur and chlorine fixation agent is controlled at 3-8 parts: if it is too high (> 8 parts), the ash content is increased and the thermal efficiency is reduced; if it is too low (< 3 parts), SOx and HCl emissions (target ≤10 mg / m³ and ≤50-200 mg / m³) cannot be effectively controlled; the denitration agent is controlled at 1-3 parts: if it is too high (> 3 parts), the cost is increased and ammonia escape may be caused; if it is too low (< 1 part), the NOx emission exceeds the standard (target ≤50-200 mg / m³); the ash content regulator is controlled at 2-5 parts: if it is too high (> 5 parts), the ash content is increased and the heat value is reduced; if it is too low (< 2 parts), the ash melting point is less than 1200°C and slagging is easy to occur.

[0010] The further limited technical solutions of the present application are: Further, in the aforementioned biomass fuel rod, the biomass raw material is a combination of one or more of straw, sawdust, rice husk, reed, domestic sludge and garden landscaping waste high-carbon content biomass with a particle size of ≤2mm.

[0011] In the aforementioned biomass fuel rod, the binder is at least one of sodium lignosulfonate or starch; and the combustion aid is at least one of potassium nitrate or calcium peroxide.

[0012] In the aforementioned biomass fuel rod, the sulfur and chlorine fixation agent is encapsulated calcium oxide. The encapsulation is specifically: (1) dispersing the calcium oxide in a non-aqueous solvent to avoid water reaction; (2) adding a heat-sensitive polymer solution to step (1) to dissolve in the non-aqueous solvent, mixing uniformly to coat the particles, and the decomposition temperature of the heat-sensitive polymer is 200-500°C to ensure decomposition during the combustion process; (3) removing the non-aqueous solvent by solvent evaporation method to form calcium-based particles wrapped by polymers, and the particle diameter range is 5-20 microns to ensure uniform distribution in the fuel rod; The non-aqueous solvent is toluene or dichloromethane; and the heat-sensitive polymer solution is polylactic acid, polystyrene or polymethyl methacrylate.

[0013] Technical effects, during the combustion process of biomass fuel rods, sulfur and chlorine-containing organic matter decomposes to produce SO2, HCl and other acidic gases, direct emission will cause acid rain and equipment corrosion, traditional calcium-based sulfur fixer (such as CaO, Ca (OH)2) is easy to absorb moisture and caking, and the reaction efficiency with sulfur and chlorine is limited by the dispersion of particles, the present application adopts a sulfur and chlorine fixing agent, and is an encapsulated sulfur and chlorine fixing agent, aiming to solve the contradiction between storage stability and reaction activity of calcium-based materials, while efficiently fixing sulfur and chlorine, reducing pollution emissions; The present application adopts a heat-sensitive polymer packaging layer to avoid contact between calcium-based particles and environmental moisture, long-term stability, release of active ingredients at combustion temperature, sulfur and chlorine fixation; the decomposition products of the packaging material are CO2 and H2O, no secondary pollution, green and environmentally friendly, the mechanism of action is: Calcium oxide: reacts with SO2 at high temperature to generate CaSO4 (melting point 1450℃), reaction formula: 2CaO + 2SO2 + O2→ 2CaSO4; reacts with HCl gas to generate CaCl2, reaction formula: CaO + 2HCl → CaCl2 + H2O, inhibits HCl emission. (2) Calcium hydroxide: releases CaO after dehydration, and directly reacts with SO2 to generate CaSO3 (subsequently oxidized to CaSO4), reaction formula: Ca (OH)2 + SO2 → CaSO3 + H2O; neutralizes HCl to generate CaCl2, reaction formula: Ca (OH)2 + 2HCl → CaCl2 + 2H2O, reduces acid corrosion.

[0014] In the foregoing biomass fuel rod, the denitration agent uses a denitration agent of the prior art or a preferably improved denitration agent, and the preparation method of the modified denitration agent is specifically as follows: (1) respectively take copper salt and iron salt, and proportion according to the molar ratio of Cu to Fe being 1:1-3:1, dissolve the copper salt and iron salt in deionized water to form a mixed metal salt solution, and the total concentration of the mixed metal salt solution is 0.1-1 mol / L; The copper salt is at least one of copper nitrate and copper sulfate; the iron salt is at least one of iron nitrate and iron sulfate; (2) slowly add a precipitant solution to the mixed metal salt solution under stirring, the dropping speed is 1-5 mL / min, and the solution temperature is kept at 50-80℃ during the dropping process, and after the dropping is completed, continue to stir for 1-3 hours to make the precipitation reaction fully proceed; The precipitant is at least one of sodium hydroxide and sodium carbonate, and the concentration of the precipitant solution is 0.5-2 mol / L; (3) filter the precipitation product, wash it with deionized water for 3-5 times until the pH value of the washing liquid is 6.5-7.5, and then dry it at 80-120℃ for 12-24 hours to obtain a precursor. (4) Put the precursor into a muffle furnace, calcine at 400-600°C for 2-4 hours, the heating rate is 2-5°C / min, to obtain a nano-sized CuO / Fe2O3 catalytic denitration agent, the particle size is ≤50 nm, ready for use; (5) Dissolve urea in deionized water to form a urea solution, the mass concentration of the urea solution is 20-40%; (6) According to the mass ratio of nano-sized CuO / Fe2O3 catalyst to urea is 0.5-2:100 (the amount of nano-sized CuO / Fe2O3 catalyst is small, and the mass ratio is controlled at 0.5-2), the prepared nano-sized CuO / Fe2O3 catalyst is added to the urea solution, and the catalyst is uniformly dispersed in the urea solution by ultrasonic dispersion, the ultrasonic time is 15-30 minutes, and the ultrasonic power is 150-350W; (7) The uniformly dispersed solution is subjected to spray drying, the inlet air temperature of spray drying is 100-130°C, the outlet air temperature is 50-70°C, and the feeding speed is 3-10 mL / min, to obtain a urea particle loaded with CuO / Fe2O3 as the core; (8) Select a heat-sensitive polymer as the intermediate layer material, the heat-sensitive polymer is polylactic acid, dissolve the polylactic acid in an organic solvent to form a polymer solution with a mass concentration of 3-8%; The organic solvent is dichloromethane; the weight average molecular weight of polylactic acid is 60000-80000; (9) Add the core particles to the polymer solution and coat by fluidized bed coating, control the air temperature at 40-60°C, the fluidization air speed is 0.5-2 m / s, and the spraying speed of the coating liquid is 1-5 mL / min, to form an intermediate layer with a thickness of 0.1-0.3 μm on the surface of the core, and the decomposition temperature of the intermediate layer is 200-300°C; (10) Weigh sodium bicarbonate, mix it with ethyl cellulose according to the mass ratio of 3:1, add an appropriate amount of organic solvent to form a shell coating liquid; The particle size of sodium bicarbonate is 10-30 μm; the degree of substitution of ethyl cellulose is 2.4-2.6, the organic solvent is ethanol, and the mass concentration of solid components in the shell coating liquid is 10-20%; (11) The particles coated with the intermediate layer are added to the shell coating liquid, and the fluidized bed coating method is continuously used for coating, the air temperature is controlled to be 50-70℃, the fluidization wind speed is 0.8-2.5 m / s, and the spraying speed of the coating liquid is 2-6 mL / min, so that a shell with a thickness of 0.4-0.7 μm is formed on the surface of the particles, the decomposition temperature of the shell is 500-600℃, and finally the denitration agent microcapsules with a core-shell structure are obtained, and the particle size is 5-10 μm.

[0015] Technical effects, the currently used denitration agent is mainly sodium carbonate or urea, and the denitration can be realized by using sodium carbonate and urea, but the efficiency is easily limited by temperature, ammonia escape is easy to occur, and the denitration effect is poor, and the preferred improved denitration agent is a composite catalytic denitration agent microcapsule, which can improve the denitration efficiency and reduce secondary pollution by using the composite catalytic denitration agent and release technology, improve the denitration efficiency, and reduce ammonia escape. When the denitration agent is improved, a nanoscale CuO / Fe2O3 catalyst is prepared, which is not simply physically mixed with nanoscale CuO and Fe2O3 in proportion, but needs to be chemically combined or synergized on the nanoscale through the above specific preparation method, steps (1)-(4) describe the preparation process of the nanoscale CuO / Fe2O3 catalytic denitration agent, including the proportioning of copper salt and iron salt (Cu:Fe=1:1-3:1), precipitation, drying and calcination (400-600°C, particle size ≤50 nm), which has a specific particle size and component ratio, and higher specificity, so as to obtain a denitration agent with better denitration effect.

[0016] Mechanism: low temperature section (200-300℃): intermediate layer decomposition, release of CuO / Fe2O3 catalyst, activation of urea decomposition; Medium temperature section (300-500℃): urea in the core is decomposed into NH3, which is reduced to NOx under the action of the catalyst; High temperature section (500-800℃): shell NaHCO3 is decomposed into Na2CO3, which further absorbs NOx.

[0017] CuO / Fe2O3 catalyst: Catalyze the decomposition of urea into NH3 at 300-500℃, reaction formula: CO (NH2)2→NH3↑+ HNCO (isocyanic acid) Catalyze the reaction of NH3 and NOx to generate N2 and H2O, reaction formula: 4NH3+ 4NO + O2→4N2+6H2O Supported NaHCO3 microcapsule: encapsulate NaHCO3 in a heat-sensitive polymer (e.g., polylactic acid), which decomposes into Na2CO3 and CO2 at 600-800°C, reaction: 2NaHCO3→ Na2CO3+ CO2↑+ H2O↑ Na2CO3 reacts with NOx to form NaNO3, reaction: Na2CO3+ 2NO2→ NaNO3+ NaNO2 + CO2↑.

[0018] In the aforementioned biomass fuel rod, the ash adjusting agent is at least one of synthetic modified calcium silicate, kaolin, or limestone, for increasing the ash melting point to ≥1200°C, in industrial boilers and gasifiers, the ash melting point usually needs to be higher than 1200°C to prevent slagging and ash accumulation, and an ash melting point higher than 1200°C is considered to be low risk, suitable for most combustion systems, and after adding the ash adjusting agent, the melting point can be significantly increased, preferably to 1200°C-1400°C; Preferably, the ash adjusting agent is synthetic modified calcium silicate, and the preparation method of the synthetic modified calcium silicate is specifically as follows: (1) Raw material pretreatment and mechanical-chemical activation: grind CaCO3, SiO2, Al2O3, and TiO2 together to a particle size ≤10 μm, particles with a particle size ≤10 μm can be uniformly distributed in the biomass fuel rod and effectively react with the ash, grind for 4 hours using a planetary ball mill, and then add 0.5wt% stearic acid to inhibit agglomeration; The purity of CaCO3 is ≥99%, the purity of SiO2 is ≥99%, the molar concentration of Al2O3 is 5-8 mol%, and the molar concentration of TiO2 is 3-5 mol%; The mass ratio of balls to material is 10:1 during planetary ball milling, the rotation speed is 600 rpm, and argon is used for protection during the ball milling process; (2) Microwave-assisted rapid sintering: place the activated precursor mixture in a silicon carbide crucible, heat at a rate of 100°C / min to 1200°C in a microwave sintering furnace, and keep the temperature for 2 hours; (3) Surface functionalization modification: grind the sintered product to 5-20 μm, disperse it in an ethanol solution, add 3wt% silane coupling agent containing a phosphorus functional group, ultrasonic treatment for 30 minutes, filter and dry, and then heat treat at 300°C for 2 hours to obtain the modified calcium silicate; The silane coupling agent is a phosphate silane.

[0019] Technical effects, biomass fuel rod combustion, ash in low melting point material (such as alkali metal salt, iron / magnesium silicate) is easy to melt at high temperature, form fly ash particles with flue gas emission, cause air pollution, the present application adds ash modifier aims at improving the melting point of ash by chemical modification, reduce the generation of molten fly ash, at the same time inhibit the phenomenon of slagging, reduce the emission of fly ash, improve the combustion efficiency and environmental protection, the specific mechanism of action as follows: (1) kaolin: dehydration generates mullite (3Al2O3・2SiO2) and free SiO2 at high temperature, mullite melting point is as high as 1810℃, the easy melting component in ash is wrapped, and the aluminum silicon tetrahedral structure can capture alkali metal ions to form stable aluminosilicate, avoiding its migration to the gas phase; (2) limestone: decomposition generates CaO, reacts with SiO2 and Al2O3 in ash to generate high melting point calcium aluminosilicate (such as 3CaO・SiO2, melting point 2130℃), the alkalinity of CaO neutralizes the acidic substances (such as SO2) in ash, reduces the formation of corrosive fly ash.

[0020] (3) modified calcium silicate forms high-temperature solid solution (CaO-SiO2-Al2O3-TiO2) by Al2O3-TiO2 doping, and the lattice distortion effect hinders the generation of fusible phase (such as K2CaSi4O 10 ), and the surface phosphate modification layer blocks the penetration of alkali metal ions such as K⁺ / Na⁺ through electrostatic repulsion, thereby forming a double anti-melting barrier to reduce fly ash emission.

[0021] The preparation method of the synthetic modified calcium silicate in the present application is that step (1) is the pretreatment and mechanical chemical activation of raw materials, the amorphization of the precursor reduces the reaction temperature from 1200℃ to 950℃, and the time is shortened by 50%, and the mechanical activation reduces the energy input required for subsequent sintering, and reduces the cost, and the specific mechanism of action is as follows: The high-energy collision (such as 600rpm speed) of the planetary ball mill makes CaCO3 / SiO2 particles produce lattice defects (such as oxygen vacancies) and amorphization (XRD peak broadening), forming a high-activity amorphous precursor, and during the grinding process, Al³⁺ and Ti 4 ⁺ ions enter the lattice by replacing Ca²⁺ and Si 4 ⁺, forming solid solution nucleus (such as Ca 1-X Al X SiO4), reducing the activation energy (ΔE from 200 kJ / mol of traditional solid phase reaction to 120 kJ / mol) of subsequent reaction, stearic acid (C 17 H 35COOH) is physically adsorbed on the particle surface, reducing the surface energy and inhibiting agglomeration. Its carboxylic acid group forms a coordination bond with Ca²⁺, further promoting the uniform dispersion of Al2O3-TiO2.

[0022] In step (2), a microwave sintering furnace is used. Microwave selective heating avoids local overheating, reduces abnormal grain growth, and reduces energy consumption. The specific mechanism of action is: The CaO / SiO2 mixture generates internal heat in the microwave field through dipole steering polarization (Ca²⁺-O²⁻ bond rotation) and interface polarization (charge accumulation at the particle boundary). The microwave energy is directly converted into lattice vibration energy, which increases the sintering driving force (surface energy / volume energy ratio) and promotes particle rearrangement and neck growth.

[0023] Step (3) performs surface functional modification to further increase the ash melting point and reduce the slagging rate. The specific mechanism of action is: The modified surface is positively charged due to the protonation of amino groups (-NH3⁺), which hinders the diffusion of K⁺ and Na⁺ into the interior of the calcium silicate through electrostatic repulsion. The phosphate group (PO4³⁻) in the modified layer is negatively charged and can capture alkali metal cations (such as K⁺ and Na⁺) released during biomass combustion through electrostatic attraction, thereby forming a double anti-melting barrier, enhancing the ability of synthetic calcium silicate to resist alkali metal corrosion in biomass, and thus improving its high-temperature stability as an ash regulator.

[0024] The present invention also relates to a method for producing a biomass fuel rod, which specifically comprises the following steps: (1) Pretreatment: The biomass raw materials are crushed to a particle size of ≤2 mm and pretreated by baking and semi-carbonization; (2) Mixing: Add binder, combustion aid, sulfur-fixing and chlorine-fixing agent, denitrification agent and ash regulator ground to a particle size of ≤2mm in sequence, and stir for 5-10 minutes; (3) Molding: A twin-screw extruder is used to extrude the fuel rods at a pressure of 15-25 MPa and a temperature of 80-100°C to obtain a fuel rod with a density of 1.2-1.4 g / cm³.

[0025] The technical solution further defined in the present invention is that in the aforementioned method for producing biomass fuel rods, the specific process of baking semi-carbonization in step (1) is: (1) Biomass raw materials crushed to ≤2 mm were mixed with K2CO3 (0.5-1 wt%) and placed in a rotary baking oven. The temperature was controlled in stages: 120°C for 30 minutes → 180°C for 1 hour → 250°C for 2 hours → 300°C for 1 hour. The total processing time was 4.5 hours. (2) The baked product is washed with deionized water until it is neutral to remove residual K2CO3; (3) Hot air drying at 100-120℃ to moisture content ≤10%, forming semi-coke fuel with hierarchical pores.

[0026] Technical effects: In the prior art, the calorific value is generally improved by adding biochar, and the carbon content of the biomass raw material itself is low (45%-50%) and the ash content is high (8%-15%) (such direct addition of biochar and simple mixing cannot change the low carbon content and high ash content characteristics of the biomass itself; secondly, biochar may introduce additional ash, especially unoptimized biochar, which may contain high alkali metals (such as K, Na), aggravating the problem of low melting point of ash; finally, the addition of biochar requires separate preparation of biochar (usually pyrolysis at 500-800°C), which has higher energy consumption than semi-carbonization baking, and the cost of directly purchasing commercial biochar for blending is also higher. Compared with adding biochar, the present application realizes biomass staged carbonization through gradient temperature control, removes non-carbon components while retaining the carbon skeleton, and introduces a chemical activator to directionally regulate the pore structure, effectively improving the calorific value of biomass, breaking through the performance bottleneck of traditional pretreatment technology, and the mechanism is as follows: (1) Gradient baking semi-carbonization: Low temperature section (120-180℃): Evaporation of free water and part of bound water in biomass, lignin begins to soften, forming initial pores; Medium temperature section (180-250℃): Cellulose is hydrolyzed into glucose, which is further dehydrated and condensed into coal-like substances (semi-coke), while releasing CO2 and H2O, reaction formula: C6H 10 O5 (cellulose) → C3H4O (semi-coke) + CO2↑ + H2O↑; High temperature section (250-300℃): Semi-coke is further carbonized, and aromatic structure is formed, while added potassium carbonate (K2CO3) is decomposed into K2O, which catalyzes carbon chain breaking and recombination, increasing fixed carbon content.

[0027] (2) Chemical activation synergy: K2CO3 is added during baking semi-carbonization, K2CO3 acts: decomposes into K2O and CO2 at 250-300℃, K2O inserts between carbon layers to form micropores, reaction formula: K2CO3→K2O+CO2↑.

[0028] The present application also relates to an application of the biomass fuel rod in industrial boilers or civilian heating equipment, when applied to combustion, SOx emission ≤10mg / m 3 , NOx emission ≤50-200mg / m 3 , HCl emission ≤50-200mg / m 3 .

[0029] The beneficial effects of the present application are: The present application improves various processes, and the processes complement each other. The baking and semi-carbonization of the biomass raw material significantly improves the gross calorific value. The ash adjusting agent is a synthetic modified calcium silicate, which reduces the ash content and reduces the amount of ash adjusting agent. The sulfur and chlorine fixation agent is used for packaging, which prolongs the service life and improves the environmental protection. After the overall improvement, the biomass has voids, which improves the combustion performance and environmental performance of the biomass fuel rod. DETAILED DESCRIPTION Example 1

[0030] The biomass fuel rod provided in this embodiment includes the following components by mass fraction: biomass raw material: 60 parts, binder: 10 parts, combustion improver: 1 part, sulfur and chlorine fixation agent: 3 parts, denitration agent: 1 part, and ash adjusting agent: 2 parts.

[0031] The production method of the biomass fuel rod includes the following steps: (1) Pretreatment: The biomass raw material is crushed to a particle size of ≤2 mm, and baking and semi-carbonization is used for pretreatment; The specific process of baking and semi-carbonization is as follows: The biomass raw material crushed to ≤2 mm is mixed with K2CO3 and placed in a rotary baking furnace. The temperature is controlled in stages: 120°C for 30 minutes, 180°C for 1 hour, 250°C for 2 hours, and 300°C for 1 hour. The total processing time is 4.5 hours; When the biomass raw material is mixed with K2CO3, the mass percentage of K2CO3 is 0.5 wt%, and the remaining amount is 99.5 wt% of the biomass raw material; The baking product is washed with deionized water until it is neutral, and the residual K2CO3 is removed; The product is dried at 100°C with hot air until the moisture content is ≤10%, forming a semi-coke fuel with graded pores; (2) Mixing: The binder, combustion improver, sulfur and chlorine fixation agent, denitration agent, and ash adjusting agent ground to a particle size of ≤2 mm are added in sequence, and stirred and mixed for 5 minutes; (3) Forming: The double-screw extruder is used for extrusion forming at a pressure of 15 MPa and a temperature of 80°C, and the fuel rod with a density of 1.2 g / cm³ is obtained.

[0032] The biomass fuel rod is used in industrial boilers or domestic heating equipment. When the fuel is burned, the SOx emission is ≤10 mg / m 3 , the NOx emission is ≤80 mg / m 3 , and the HCl emission is ≤70 mg / m 3 .

[0033] In this embodiment, the biomass raw material is a combination of straw, sawdust, and rice husk with a particle size of ≤2 mm. The binder is sodium lignosulfonate, and the combustion improver is potassium nitrate.

[0034] In this embodiment, the sulfur and chlorine fixation agent is encapsulated calcium oxide, and the encapsulation is as follows: (1) dispersing calcium oxide in a non-aqueous solvent to avoid moisture reaction; (2) adding a heat-sensitive polymer solution to step (1) to dissolve in the non-aqueous solvent, and mixing uniformly to coat the particles, the decomposition temperature of the heat-sensitive polymer being 200°C; (3) removing the non-aqueous solvent by solvent evaporation method to form polymer-coated calcium-based particles, the particle diameter being in the range of 15 microns; The non-aqueous solvent is toluene; the heat-sensitive polymer solution is polylactic acid.

[0035] In this embodiment, the denitration agent is sodium carbonate.

[0036] In this embodiment, the ash adjusting agent is kaolin, which is used to raise the ash melting point to ≥1200°C. Embodiment 2

[0037] This embodiment provides a biomass fuel rod, which comprises the following components by mass fraction: biomass raw material: 70 parts, binder: 15 parts, combustion improver: 2 parts, sulfur and chlorine fixation agent: 5 parts, denitration agent: 2 parts, ash adjusting agent: 3 parts.

[0038] The production method of the above biomass fuel rod specifically comprises the following steps: (1) pretreatment: crushing the biomass raw material to a particle size ≤2 mm, and pretreating by baking and semi-carbonization; The specific process of baking and semi-carbonization is as follows: Mix the biomass raw material crushed to ≤2 mm with K2CO3, and place it in a rotary baking furnace, with segmented temperature control: 120°C for 30 minutes → 180°C for 1 hour → 250°C for 2 hours → 300°C for 1 hour, with a total processing time of 4.5 hours; When mixing the biomass raw material with K2CO3, the K2CO3 is 0.8 wt% by mass percentage, and the balance is 99.2 wt% of the biomass raw material; The baking product is washed with deionized water until neutral to remove residual K2CO3; Heat air dry at 105°C to a moisture content ≤10% to form a semi-coke fuel with graded porosity; (2) mixing: adding the binder, combustion improver, sulfur and chlorine fixation agent, denitration agent, and ash adjusting agent ground to a particle size ≤2 mm in sequence, and stirring and mixing for 8 minutes; (3) molding: using a double-screw extruder to extrude and form at a pressure of 20 MPa and a temperature of 90°C to obtain a fuel rod with a density of 1.3 g / cm³.

[0039] The biomass fuel rod is applied in an industrial boiler or a civilian heating device, and the SOx emission is less than or equal to 10 mg / m 3 , the NOx emission is less than or equal to 50 mg / m 3 , and the HCl emission is less than or equal to 50 mg / m 3 .

[0040] In the embodiment, the biomass raw material is a combination of straw, sawdust, rice husk and reed with a particle size of less than or equal to 2 mm; the binder is starch; and the combustion-supporting agent is calcium peroxide.

[0041] In the embodiment, the sulfur-fixing and chlorine-fixing agent is encapsulated calcium oxide, and the encapsulation is specifically as follows: (1) dispersing the calcium oxide in a non-aqueous solvent to avoid water reaction; (2) adding a heat-sensitive polymer solution to the step (1) to dissolve in the non-aqueous solvent, uniformly mixing to coat the particles, and the decomposition temperature of the heat-sensitive polymer is 300℃; (3) removing the non-aqueous solvent by a solvent evaporation method to form calcium-based particles wrapped by the polymer, and the particle diameter ranges from 5 microns; The non-aqueous solvent is dichloromethane; and the heat-sensitive polymer solution is polystyrene.

[0042] In the embodiment, the preparation method of the denitration agent is specifically as follows: (1) respectively weighing copper salt and iron salt, and proportioning according to a molar ratio of Cu to Fe of 2:1, dissolving the copper salt and the iron salt in deionized water to form a metal salt mixed solution, and the total concentration of the metal salt mixed solution is 0.5 mol / L; The copper salt is copper sulfate; and the iron salt is iron sulfate; (2) slowly adding a precipitant solution to the metal salt mixed solution under stirring, the dropping speed is 2 mL / min, the solution temperature is kept at 60℃ during the dropping process, and after the dropping is completed, the stirring is continued for 2 hours to make the precipitation reaction fully proceed; The precipitant is sodium carbonate, and the concentration of the precipitant solution is 1.1 mol / L; (3) filtering the precipitation product, washing with deionized water for 4 times until the pH value of the washing liquid approaches to neutral, and then drying at 100℃ for 18 hours to obtain a precursor; (4) placing the precursor in a muffle furnace, calcining at 500℃ for 3 hours with a heating rate of 4℃ / min to obtain a nano-sized CuO / Fe2O3 catalytic denitration agent with a particle size of less than or equal to 50 nm, which is ready for use; (5) dissolving urea in deionized water to form a urea solution, and the mass concentration of the urea solution is 30%; (6) According to the mass ratio of the nanoscale CuO / Fe2O3 catalyst to urea being 2:100, the prepared nanoscale CuO / Fe2O3 catalyst is added into the urea solution, and the catalyst is uniformly dispersed in the urea solution by ultrasonic dispersion, the ultrasonic time is 20 minutes, and the ultrasonic power is 220 W; (7) The uniformly dispersed solution is subjected to spray drying, the inlet air temperature of the spray drying is 120°C, the outlet air temperature is 60°C, and the feeding speed is 5 mL / min, so as to obtain the urea particles loaded with CuO / Fe2O3 as the inner core; (8) The heat-sensitive polymer is selected as the intermediate layer material, the heat-sensitive polymer is polylactic acid, the polylactic acid is dissolved in an organic solvent to form a polymer solution with a mass concentration of 5%; The organic solvent is dichloromethane, and the weight average molecular weight of the polylactic acid is 70000; (9) The inner core particles are added into the polymer solution, and the fluidized bed coating is adopted to perform coating, the air temperature is controlled to be 50°C during the coating process, the fluidization air speed is 1 m / s, and the spraying speed of the coating liquid is 2 mL / min, so as to form an intermediate layer with a thickness of 0.2 μm on the surface of the inner core, and the decomposition temperature of the intermediate layer is 250°C; (10) The sodium bicarbonate is weighed, mixed with the ethyl cellulose according to the mass ratio of 3:1, and an appropriate amount of organic solvent is added to form a shell coating liquid; The particle size of the sodium bicarbonate is 20 μm, the degree of substitution of the ethyl cellulose is 2.5, the organic solvent is ethanol, and the mass concentration of the solid components in the shell coating liquid is 15%; (11) The particles coated with the intermediate layer are added into the shell coating liquid, and the fluidized bed coating is continued to perform coating, the air temperature is controlled to be 60°C during the coating process, the fluidization air speed is 1.1 m / s, and the spraying speed of the coating liquid is 4 mL / min, so as to form a shell with a thickness of 0.5 μm on the surface of the particles, the decomposition temperature of the shell is 550°C, and finally the denitration agent microcapsules with a core-shell structure are obtained, and the particle size is 5 μm.

[0043] In this embodiment, the ash conditioner is a synthetic modified calcium silicate, which is used to raise the ash melting point to 1400°C.

[0044] The preparation method of the above-mentioned synthetic modified calcium silicate is specifically as follows: (1) Raw material pretreatment and mechanical chemical activation: CaCO3, SiO2, Al2O3 and TiO2 are ground together to a particle size of ≤10 μm, a planetary ball mill is used for grinding for 4 hours, and then 0.5wt% of stearic acid is added to inhibit agglomeration; The purity of CaCO3 is ≥99%, the purity of SiO2 is ≥99%, the molar concentration of Al2O3 is 7 mol%, and the molar concentration of TiO2 is 4 mol%; The ball-to-material mass ratio during the planetary ball milling was 10:1, the rotation speed was 600 rpm, and argon gas was used as protection during the graphite process; (2) Microwave-assisted rapid sintering: The activated precursor mixture was placed in a silicon carbide crucible, and the temperature was raised to 1200°C at 100°C / min in a microwave sintering furnace and kept at this temperature for 2 hours; (3) Surface functionalization modification: The sintered product was ground to 14 μm and dispersed in an ethanol solution. 3 wt% of phosphorus-containing functional group silane coupling agent phosphate silane was added. The product was ultrasonically treated for 30 minutes. After filtration and drying, it was heat-treated at 300 °C for 2 hours to obtain modified calcium silicate. Example 3

[0045] This embodiment provides a biomass fuel rod, which includes the following components by mass: biomass raw material: 80 parts, binder: 20 parts, combustion aid: 5 parts, sulfur-fixing and chlorine-fixing agent: 8 parts, denitrification agent: 3 parts, and ash regulator: 5 parts.

[0046] The above-mentioned method for producing biomass fuel rods specifically comprises the following steps: (1) Pretreatment: The biomass raw materials are crushed to a particle size of ≤2 mm and pretreated by baking and semi-carbonization; The specific process of baking semi-carbonization is: The biomass raw materials crushed to ≤2mm were mixed with K2CO3 and placed in a rotary baking oven. The temperature was controlled in stages: 120℃ for 30 minutes → 180℃ for 1 hour → 250℃ for 2 hours → 300℃ for 1 hour. The total treatment time was 4.5 hours. When the biomass raw material is mixed with K2CO3, the K2CO3 is 1wt% by mass percentage, and the balance is the biomass raw material; The baked product was washed with deionized water until neutral to remove residual K2CO3; Drying with hot air at 120℃ until the moisture content is ≤10% to form semi-coke fuel with graded pores; (2) Mixing: Add binder, combustion aid, sulfur-fixing and chlorine-fixing agent, denitrification agent and ash regulator ground to a particle size of ≤2 mm in sequence, and stir for 10 minutes; (3) Molding: A twin-screw extruder is used to extrude the fuel rods at a pressure of 25 MPa and a temperature of 100°C to obtain a fuel rod with a density of 1.4 g / cm³.

[0047] When the above biomass fuel rods are used in industrial boilers or civil heating equipment, the SOx emissions are ≤10 mg / m3 NOx emissions ≤ 120 mg / m 3 HCl emissions ≤ 150 mg / m 3 .

[0048] In this embodiment, the biomass raw material is a combination of straw reed, domestic sludge, and landscaping waste with a particle size ≤ 2 mm; the binder is sodium lignosulfonate; and the combustion-supporting agent is potassium nitrate.

[0049] In this embodiment, the sulfur-fixing and chlorine-fixing agent is encapsulated calcium oxide, and the encapsulation is as follows: (1) Disperse the calcium oxide in a non-aqueous solvent to avoid moisture reaction; (2) Add a heat-sensitive polymer solution to the solution in step (1) to dissolve in the non-aqueous solvent, mix uniformly to coat the particles, and the decomposition temperature of the heat-sensitive polymer is 500°C; (3) Remove the non-aqueous solvent by solvent evaporation method to form calcium-based particles wrapped with polymers, and the particle size range is 20 microns; The non-aqueous solvent is dichloromethane; and the heat-sensitive polymer solution is polymethyl methacrylate.

[0050] In this embodiment, the preparation method of the denitration agent is as follows: (1) Respectively weigh the copper salt and the iron salt, and mix them according to a molar ratio of Cu to Fe of 3:1, dissolve the copper salt and the iron salt in deionized water to form a mixed metal salt solution, and the total concentration of the mixed metal salt solution is 1 mol / L; The copper salt is copper nitrate; and the iron salt is iron sulfate; (2) Under stirring conditions, slowly add a precipitant solution to the mixed metal salt solution at a speed of 5 mL / min, keep the solution temperature at 80°C during the adding process, continue stirring for 3 hours after the adding is completed, and make the precipitation reaction fully proceed; The precipitant is sodium hydroxide, and the concentration of the precipitant solution is 2 mol / L; (3) Filter the precipitate, wash it with deionized water for 5 times until the pH value of the washing liquid approaches neutral, and then dry it at 120°C for 24 hours to obtain a precursor; (4) Place the precursor in a muffle furnace, calcine it at 600°C for 4 hours with a heating rate of 5°C / min to obtain a nano-sized CuO / Fe2O3 catalytic denitration agent with a particle size ≤ 50 nm, which is ready for use; (5) Dissolve urea in deionized water to form a urea solution, and the mass concentration of the urea solution is 40%; (6) According to the mass ratio of the nanoscale CuO / Fe2O3 catalyst to urea being 1:100, the prepared nanoscale CuO / Fe2O3 catalyst is added into the urea solution, and the catalyst is uniformly dispersed in the urea solution by ultrasonic dispersion, the ultrasonic time is 30 minutes, and the ultrasonic power is 350 W; (7) The uniformly dispersed solution is subjected to spray drying, the inlet air temperature of the spray drying is 130℃, the outlet air temperature is 70℃, and the feeding speed is 10 mL / min, so as to obtain the urea particles loaded with CuO / Fe2O3 as the inner core; (8) A heat-sensitive polymer is selected as the intermediate layer material, the heat-sensitive polymer is polylactic acid, the polylactic acid is dissolved in an organic solvent to form a polymer solution with a mass concentration of 8%; The organic solvent is dichloromethane, and the weight average molecular weight of the polylactic acid is 80000; (9) The inner core particles are added into the polymer solution, and a fluidized bed coating method is used for coating, the air temperature is controlled to be 60℃ during the coating process, the fluidization air speed is 2 m / s, and the spraying speed of the coating liquid is 5 mL / min, so as to form an intermediate layer with a thickness of 0.3 μm on the surface of the inner core, and the decomposition temperature of the intermediate layer is 300℃; (10) Sodium bicarbonate is weighed, mixed with ethyl cellulose according to the mass ratio of 3:1, and an appropriate amount of organic solvent is added to form a shell coating liquid; The particle size of the sodium bicarbonate is 30 μm, the degree of substitution of the ethyl cellulose is 2.6, the organic solvent is ethanol, and the mass concentration of the solid components in the shell coating liquid is 20%; (11) The particles coated with the intermediate layer are added into the shell coating liquid, and the fluidized bed coating method is further used for coating, the air temperature is controlled to be 70℃ during the coating process, the fluidization air speed is 0.8-2.5 m / s, and the spraying speed of the coating liquid is 2-6 mL / min, so as to form a shell with a thickness of 0.4-0.7 μm on the surface of the particles, the decomposition temperature of the shell is 500-600℃, and finally the denitration agent microcapsules with a core-shell structure are obtained, and the particle size is 5-10 μm.

[0051] In this embodiment, the ash conditioner is a synthetic modified calcium silicate, which is used to raise the ash melting point to 1400℃.

[0052] The preparation method of the above-mentioned synthetic modified calcium silicate is specifically as follows: (1) Raw material pretreatment and mechanical chemical activation: CaCO3, SiO2, Al2O3 and TiO2 are ground together to a particle size of ≤10 μm, a planetary ball mill is used for grinding for 4 hours, and then 0.5wt% of stearic acid is added to inhibit agglomeration; CaCO3 purity ≥ 99%, SiO2 purity ≥ 99%, Al2O3 molar concentration 8 mol%, TiO2 molar concentration 5 mol%; The planetary ball mill grinds the balls and the material at a mass ratio of 10:1 and a rotation speed of 600 rpm, and argon is protected during the ball milling process. (2) Microwave-assisted rapid sintering: After activation, the mixture is placed in a silicon carbide crucible and heated to 1200°C at a rate of 100°C / min in a microwave sintering furnace, and held for 2 hours. (3) Surface functionalization modification: After grinding the sintered product to 20 μm, it is dispersed in an ethanol solution, 3wt% phosphorus-containing functional group silane coupling agent phosphate silane is added, ultrasonic treatment for 30 minutes, filtration and drying, and then heat treatment at 300°C for 2 hours to obtain the modified calcium silicate.

[0053] Comparative Example 1

[0054] The biomass fuel rod of Comparative Example 1 is pure biomass without functional additives, and the components are as follows in mass parts: biomass raw material (straw, sawdust, rice husk, particle size ≤2 mm) 90 parts, binder (sodium lignosulfonate) 10 parts, and no other additives.

[0055] The biomass raw material is crushed to a particle size of ≤2 mm and mixed uniformly with the binder, and a double screw extruder (pressure 15 MPa, temperature 80°C) is used for molding, with a density of 1.05 g / cm³, without semi-carbonization or functional additive treatment.

[0056] Comparative Example 2

[0057] Comparative Example 2 is a low combustion-supporting agent ratio fuel rod, and the components are as follows in mass parts: biomass raw material (straw, sawdust, rice husk mixture, particle size ≤2 mm) 80 parts, binder (sodium lignosulfonate) 10 parts, combustion-supporting agent (potassium nitrate) 0.5 parts, no sulfur-fixing and chlorine-fixing agent, denitration agent, and ash adjusting agent.

[0058] The raw material is crushed to a particle size of ≤2 mm and mixed uniformly, and a double screw extruder (pressure 15 MPa, temperature 80°C) is used for molding, with a density of 1.10 g / cm³, without semi-carbonization.

[0059] Comparative Example 3

[0060] Comparative Example 3 is a low sulfur-fixing and chlorine-fixing agent and denitration agent ratio fuel rod, and the components are as follows in mass parts: biomass raw material (straw, sawdust, rice husk mixture, particle size ≤2 mm) 75 parts, binder (sodium lignosulfonate) 15 parts, sulfur-fixing and chlorine-fixing agent (limestone) 2 parts, denitration agent (urea) 0.5 parts, no combustion-supporting agent and ash adjusting agent.

[0061] The raw materials were crushed to a particle size of ≤2 mm, mixed uniformly, and molded using a double-screw extruder (pressure 15 MPa, temperature 80°C), with a density of 1.15 g / cm3, without semi-carbonization.

[0062] Comparative Example 4

[0063] Comparative Example 4 is a high-ash modifier proportion fuel rod, with components in parts by mass as follows: biomass raw material (straw, sawdust, rice husk mixed, particle size ≤2 mm) 60 parts, binder (sodium lignosulfonate) 10 parts, combustion-supporting agent (potassium nitrate) 1 part, sulfur and chlorine fixation agent (limestone) 3 parts, denitration agent (urea) 1 part, ash modifier (kaolin) 10 parts.

[0064] The raw materials were crushed to a particle size of ≤2 mm, mixed uniformly, and molded using a double-screw extruder (pressure 15 MPa, temperature 80°C), with a density of 1.20 g / cm3, without semi-carbonization.

[0065] Comparative Example 5

[0066] Comparative Example 5 differs from Example 1 in that the proportion of biomass raw material is increased to 90 parts, with other components and preparation methods remaining unchanged. The performance of the biomass fuel rods in Comparative Examples 1-5 and the fuel rods produced in Examples 1-3 are compared, as shown in Table 1. Table 1 Performance Index Comparison Table Index Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Example 1 Example 2 Example 3 Calorific value (MJ / kg) 16.42 17.89 17.53 18.27 18.47 19.85 21.36 22.67 Combustion rate (%) 71.63 76.28 75.41 78.46 78.23 83.47 87.92 90.82 Thermal efficiency (%) 62.37 67.45 66.73 68.92 68.15 73.28 77.65 80.64 Moisture content (%) 14.78 13.29 12.94 12.63 9.12 8.63 7.81 6.91 Ash content (%) 11.94 13.76 12.47 15.81 10.37 7.08 6.19 5.27 Sulfur fixation rate (%) 19.82 28.63 32.64 37.45 70.48 89.61 92.83 95.94 Chlorine fixation rate (%) 29.63 39.28 42.89 48.37 75.62 91.82 94.76 90.15 NOx emission (mg / m³) 428.36 376.82 347.82 326.47 251.39 76.53 56.74 94.28 SOx emission (mg / m³) 61.89 51.47 47.95 45.63 29.74 9.81 8.14 7.36 HCl emission (mg / m³) 317.82 286.15 251.47 238.92 149.85 64.73 52.46 96.17 Ash melting point (°C) 921.73 962.48 986.15 1018.62 1002.76 1228.46 1312.95 1391.27 The biomass fuel rods produced in Comparative Examples 1-5 and Examples 1-3 were tested using existing technology, and as can be seen from Table 1: The functional additives of the comparative example 1 are insufficient due to the lack of combustion improver, sulfur and chlorine fixation agent, denitration agent and ash adjusting agent, which results in low heat value (16.42 MJ / kg), high emission (NOx 428.36 mg / m3, HC1 317.82 mg / m3), low ash melting point (921.73 °C) and easy slagging, which indicates that the high biomass ratio (> 80 parts) leads to insufficient functionality; the combustion improver ratio in the comparative example 2 is too low (0.5 parts, lower than the patent range of 1-5 parts), and other functional additives are lacking, which leads to insufficient combustion, low heat value and combustion rate (76.28%), thermal efficiency 67.45%, and high emission, which indicates the deficiency of low combustion improver ratio (< 1 part); the sulfur and chlorine fixation agent (2 parts, lower than the patent range of 3-8 parts) and the denitration agent (0.5 parts, lower than the patent range of 1-3 parts) in the comparative example 3 lead to poor control of SOx, HC1 and NOx emissions (SOx 47.95 mg / m3, HC1 251.47 mg / m3), and low ash melting point (986.15 °C), which indicates the limitations of low sulfur and chlorine fixation agent and denitration agent ratio; the ash adjusting agent ratio in the comparative example 4 is too high (10 parts, exceeding the patent range of 2-5 parts), which leads to increased ash content (15.81%), decreased heat value (18.27 MJ / kg) and combustion efficiency (78.46%), which indicates the negative effects of high ash adjusting agent ratio (> 5 parts); in the comparative example 5, the biomass raw material ratio is as high as 90 parts, the heat value decreases from 19.85 MJ / kg to 18.47 MJ / kg, the combustion rate decreases from 83.47% to 78.23%, and the thermal efficiency decreases from 73.28% to 68.15%. In addition, the NOx emission increases from 76.53 mg / m3 to 251.39 mg / m3, the SOx emission increases from 9.81 mg / m3 to 29.74 mg / m3, the HC1 emission increases from 64.73 mg / m3 to 149.85 mg / m3, the sulfur fixation rate and chlorine fixation rate decrease from 89.61% and 91.82% to 70.48% and 75.62%, respectively, and the ash melting point decreases from 1228.46 °C to 1002.76 °C. These performance declines are attributed to the high biomass raw material ratio leading to insufficient relative ratio of functional additives (sulfur and chlorine fixation agent, denitration agent, ash adjusting agent), which weakens the emission control and anti-slagging ability. Controlling the biomass raw material in the range of 60-80 parts can ensure the effective ratio of functional additives, improve the heat value, combustion efficiency, emission control and anti-slagging performance, and meet the patent target (SOx≤10 mg / m3, NOx≤50-200 mg / m3, HC1≤50-200 mg / m3, ash melting point≥1200 °C).

[0067] The biomass fuel rod produced by the application has a maximum calorific value of 22.67 MJ / kg, a maximum combustion rate of 90.82%, a maximum thermal efficiency of 80.64%, and greatly reduced moisture and ash content, greatly increased sulfur and chlorine fixation rate, and, when applied to combustion, NOx emission of 56.74 mg / m 3 , SOx emission of 7.36 mg / m 3 , HClx emission of 52.46 mg / m 3 , and ash melting point of 1391.27, close to 1400℃, greatly reducing the risk. Compared with traditional pure biomass, the biomass fuel rod of the application has good combustion performance, significantly improved combustion efficiency and environmental protection, and has a wide prospect.

[0068] In addition to the above embodiments, the application can have other implementation manners. Any technical solution formed by equivalent replacement or equivalent transformation falls within the protection scope required by the application.

Claims

1. A biomass fuel rod, characterized by, The biomass raw material, the binder, the combustion-supporting agent, the sulfur and chlorine fixation agent, the denitration agent, and the ash adjusting agent are mixed in a mass ratio of 60-80:10-20:1-5:3-8:1-3:2-5.

2. The biomass fuel rod of claim 1, wherein: The biomass raw material is one or more of straw, sawdust, rice husk, reed, domestic sludge, and garden greening waste high-carbon-content biomass with a particle size of ≤2 mm.

3. The biomass fuel rod of claim 1, wherein: The binder is at least one of sodium lignosulfonate or starch; and the combustion-supporting agent is at least one of potassium nitrate or calcium peroxide.

4. The biomass fuel rod of claim 1, wherein: The sulfur and chlorine fixation agent is encapsulated calcium oxide. The encapsulation specifically comprises: (1) dispersing the calcium oxide in a non-aqueous solvent to avoid moisture reaction; (2) adding a heat-sensitive polymer solution to the step (1) to dissolve in the non-aqueous solvent, and mixing uniformly to coat the particles, wherein the heat-sensitive polymer has a decomposition temperature of 200-500°C; (3) removing the non-aqueous solvent by solvent evaporation to form calcium-based particles wrapped by the polymer, wherein the particle diameter ranges from 5 to 20 microns; The non-aqueous solvent is toluene or dichloromethane; and the heat-sensitive polymer solution is polylactic acid, polystyrene, or polymethyl methacrylate.

5. The biomass fuel rod of claim 1, wherein: The ash adjusting agent is at least one of synthetic modified calcium silicate, kaolin, or limestone, which is used to raise the ash melting point to ≥1200°C.

6. The biomass fuel rod of claim 5, wherein: The preparation method of the synthetic modified calcium silicate specifically comprises: (1) grinding CaCO3, SiO2, Al2O3, and TiO2 together to a particle size of ≤10 μm, using a planetary ball mill to grind for 4 hours, and then adding 0.5wt% stearic acid to inhibit agglomeration; The purity of the CaCO3 is ≥99%, the purity of the SiO2 is ≥99%, the molar concentration of the Al2O3 is 5-8 mol%, and the molar concentration of the TiO2 is 3-5 mol%; The planetary ball mill grinds the ball and the material in a mass ratio of 10:1 at a speed of 600 rpm, and argon is used for protection during the ball milling process; (2) placing the mixture in a silicon carbide crucible, and heating to 1200°C at a rate of 100°C / min in a microwave sintering furnace, and keeping the temperature for 2 hours; (3) grinding the sintered product to 5-20 μm, dispersing it in an ethanol solution, adding 3wt% silane coupling agent containing a phosphorus functional group, ultrasonic treatment for 30 minutes, and then filtering, drying, and heat treating at 300°C for 2 hours to obtain the modified calcium silicate; The silane coupling agent is a phosphate silane.

7. A method of producing a biomass fuel rod according to claim 1, characterized by, The method specifically comprises the following steps: (1) pretreatment: crushing the biomass raw material to a particle size of ≤2 mm, and using baking semi-carbonization for pretreatment; (2) mixing: sequentially adding the binder, the combustion-supporting agent, the sulfur and chlorine fixation agent, the denitration agent, and the ash adjusting agent ground to a particle size of ≤2 mm, and stirring and mixing for 5-10 minutes; (3) forming: using a double-screw extruder to extrude at a pressure of 15-25 MPa and a temperature of 80-100°C to obtain fuel rods with a density of 1.2-1.4 g / cm³.

8. The method of producing a biomass fuel rod according to claim 7, characterized by: The baking semi-carbonization in the step (1) specifically comprises: (1) Biomass raw material crushed to ≤2mm is mixed with K2CO3 and placed in a rotary baking furnace, with temperature control in stages: 120℃ for 30 minutes, 180℃ for 1 hour, 250℃ for 2 hours, and 300℃ for 1 hour, for a total processing time of 4.5 hours; When the biomass raw material is mixed with K2CO3, the K2CO3 is 0.5-1wt% and the remainder is the biomass raw material, by mass percentage; (2) The baking product is washed with deionized water until neutral to remove residual K2CO3; (3) Hot air drying is performed at 100-120℃ until the moisture content is ≤10%, forming a semi-coke fuel with graded porosity.

9. Use of the biomass fuel rod according to claim 1 in an industrial boiler or a domestic heating device, characterized in that: SOx emissions < 10 mg / m 3 NOx emissions < 50-200 mg / m 3 HCl emissions < 50-200 mg / m 3 .