CN-121991734-A - Production process for low-temperature drying extrusion of furfural residues to prepare biomass particles

CN121991734ACN 121991734 ACN121991734 ACN 121991734ACN-121991734-A

Abstract

The invention discloses a production process for extruding biomass particles by drying furfural residues at a low temperature, and belongs to the technical field of biomass briquette preparation. The process comprises the steps of providing furfural residue with an initial water content of 50-60% and coked polymer produced by furfural production, adopting an indirect heat exchange type roller dryer to carry out low-temperature steam drying, enabling the temperature of a heat exchange surface to be 90-100 ℃, matching induced air to carry out dehumidification, controlling the water content of discharged material of the furfural residue to be 15-20%, recycling condensed water, smashing the coked polymer to be not more than 50 meshes, mixing the smashed polymer with the dried furfural residue according to a ratio of 2-5:95-98, carrying out classified ash removal through air separation and cyclone separation, outputting main materials with a size of more than 50 meshes, removing fine powder with a size of less than 50 meshes and entrained ash, and doping mineral functional agents with a weight percentage of 0.5-5wt% into the main materials and uniformly mixing. The process realizes stable water control, graded ash removal, low-temperature forming interlocking stability, and mineral internal and external cooperation anti-slagging, hydrophobic, dampproof and anti-pulverization, and improves the quality and storage stability of the granular fuel.

Inventors

LI DIANYUAN
WANG MINGZHI
He qianlong
Zhu xingqing
LI KUN
DING XIANGMING

Assignees

河南禾力能源有限公司
河南氢力能源有限公司

Dates

Publication Date: 20260508
Application Date: 20260318

Claims (10)

1. The production process of the biomass particles by low-temperature drying and extrusion of the furfural residues is characterized by comprising the following steps: s1) preparing raw materials, namely providing furfural residues, wherein the initial water content of the furfural residues is 50-60%, and providing coked polymers generated in the production process of the furfural; S2) low-temperature indirect steam drying, namely introducing saturated steam into an indirect heat exchange type roller dryer to preheat heat exchange components of the roller dryer, so that the temperature of heat exchange surfaces contacted with materials reaches 90-100 ℃, and then, introducing furfural residues into an inner barrel of the roller dryer, so that the water content of discharged furfural residues is controlled to be 15-20%; S3) pre-treating the coked polymer, namely crushing the coked polymer to obtain crushed materials with the granularity not more than 50 meshes; s4) mixing, namely uniformly mixing the dried furfural residue obtained in the step S2 with the crushed material obtained in the step S3 according to the mass ratio of coking polymer to furfural residue of 2-5:95-98; s5) carrying out air separation on the mixture, delivering the mixture into a cyclone separator for classification, controlling the granularity of the main material after classification to be more than 50 meshes, and separating and removing fine particles smaller than 50 meshes and entrained ash so as to obtain a main material for granulation; s6) adding a mineral functional agent into the main material obtained in the step S5, and uniformly mixing, wherein the mineral functional agent is at least one of silicon-aluminum minerals, carbonate minerals and zeolite, the adding amount of the mineral functional agent is 0.5-5wt% based on the mass of the main material, and the doped mineral functional agent is of which the first granularity grade is less than or equal to 100 meshes; S7) extrusion granulation, namely feeding the material obtained in the step S6 into an extrusion granulator, and performing extrusion molding through a die hole to obtain biomass particles, wherein the temperature of the extruded particles is controlled to be not higher than 80 ℃; S8) surface function coating and curing and air drying, namely after the step S7 and before sieving, carrying out double-layer surface function coating and curing and air drying on the biomass particles by utilizing the condition that the surface temperature of the biomass particles is 40-80 ℃ after extrusion molding, and carrying out mineral protection layer coating and hydrophobic shell layer coating to form core-mineral layer-hydrophobic layer structure particles, wherein the mineral layer is positioned on the inner side of the hydrophobic layer; coating a mineral protective layer, namely applying a mineral functional agent to the surfaces of biomass particles in the form of slurry or micropowder at the surface temperature of the particles of 40-70 ℃ to ensure that the application amount of the mineral functional agent is 0.2-2wt% (calculated by solid) based on the mass of the biomass particles, and drying and fixing under the action of air flow of an air drying section to form the mineral protective layer; Coating a hydrophobic shell layer, namely applying a hydrophobic coating material to the surface of biomass particles in a melting atomization spraying mode when the surface temperature of the particles is 50-80 ℃, wherein the hydrophobic coating material is at least one of natural wax, vegetable wax and bio-based hydrophobe, the application amount of the hydrophobic coating material is 0.2-2.0wt% based on the mass of the biomass particles, and solidifying the hydrophobic coating material into a film under the action of air flow of an air drying section after spraying so as to form the hydrophobic shell layer; The mineral functional agent used for forming the mineral protective layer in the step S8 and the mineral functional agent doped in the step S6 are the same mineral functional agent, the mineral functional agent on the surface layer of the step S8 is of a second granularity grade, and the second granularity grade is finer than the first granularity grade, and the second granularity grade is 200-500 meshes of micropowder; when the hydrophobic coating material contains tall oil, the mass ratio of the wax component to the tall oil is 9:1-6:4; Meanwhile, the air supply for air induction in the step S2 is subjected to heat exchange with the particles through a supporting plate/tray and then enters a roller dryer so as to realize particle cooling and air induction preheating; s9) screening and feeding back, namely screening the biomass particles air-dried in the step S8, taking the complete particles on the screen as finished products, and returning the undersize materials to the step S7 for re-granulation; S10) waste gas treatment, namely spraying, alkali neutralization and steam-water separation are carried out on the wet waste gas extracted in the step S2, then the wet waste gas is discharged, and negative pressure collection is adopted for granulating, coating, screening and packaging dust.
2. The production process of the biomass particles by low-temperature drying and extrusion of the furfural residues is characterized in that the saturated steam temperature in the step S2 is 150 ℃ and the preheating time is 20-30 min.
3. The production process of the biomass particles by low-temperature drying and extrusion of the furfural residue is characterized in that in the step S7, the material level of a granulator material bin is controlled to be 1/2-2/3 of the effective volume of the material bin, and the running load of the granulator is controlled to be 60-70% of the capacity of a nameplate.
4. The production process of the biomass particles by low-temperature drying and extrusion of the furfural residue is characterized in that the temperature of the particles is reduced to below 40 ℃ after the solidifying and air-drying in the step S8, and the particles are packaged.
5. The process for producing biomass particles by low-temperature drying and extrusion of furfural residue according to claim 1, wherein the silica-alumina mineral comprises kaolin and/or bentonite, and the carbonate mineral comprises dolomite and/or limestone powder.
6. The production process of the biomass particles by low-temperature drying and extrusion of the furfural residue is characterized in that the addition amount of the mineral functional agent in the step S6 is 1-3wt% based on the mass of the main material, and the mineral functional agent comprises zeolite.
7. The process for producing biomass particles by low-temperature drying and extrusion of furfural residue according to claim 1, wherein in step S8, a mineral protection layer is coated first, and then a hydrophobic shell layer is coated, so that a particle structure of core-mineral layer-hydrophobic layer is formed.
8. The production system for carrying out low-temperature drying extrusion of the furfural residue to obtain biomass particles is characterized by comprising a roller drying unit, an induced air unit, a coked polymer crushing unit, a mixing unit, a grading ash removal unit, a mineral functional agent feeding unit and a mixing homogenization unit, an extrusion forming granulation unit, a surface coating and curing air drying unit, a screening unit and a return conveying unit; the drum drying unit is an indirect heat exchange type drum dryer, is provided with a steam preheating pipeline and a condensed water recovery pipeline, is connected with an induced air unit, is used for smashing coked polymers generated in the furfural production process, is communicated with discharge end materials of the drum drying unit and the coked polymer smashing unit, is used for mixing dried furfural residues with smashed coked polymers, is provided with a classified ash removing unit, comprises a winnowing device and a cyclone separator, is communicated with the discharge end materials of the mixing unit, is provided with a granulating main material with the granularity of more than 50 meshes, and is used for separating and removing fine particles with the granularity of less than 50 meshes and entrained ash, is communicated with the granulating main material output by the classified ash removing unit, is used for adding mineral functional agents into the granulating main material and uniformly mixing, is communicated with the discharge end materials of the mixed ash removing unit, is used for extrusion molding, is used for obtaining biomass particles through extrusion molding, is provided with a surface coating and curing unit, comprises a supporting plate/tray conveying structure and a spraying device, is used for carrying out mineral protective layer coating and/or shell layer coating on the biomass particles, and the screening unit is used for screening the biomass particles, and the return conveying unit is used for returning the undersize products to the extrusion granulating unit.
9. The production system for low-temperature drying, extruding and pressing of biomass particles from furfural residue according to claim 8, further comprising an exhaust gas treatment unit, wherein the exhaust gas treatment unit is communicated with an exhaust gas outlet of the roller drying unit, the exhaust gas treatment unit comprises a spraying section, an alkali neutralization section and a steam-water separation section, the dust negative pressure collection unit at least covers granulating, coating, screening and packaging stations, and an air inlet path of the air inducing unit is arranged to enter the roller drying unit after heat exchange between the surface coating and curing air drying unit and the particles so as to realize air path coupling waste heat utilization.
10. The biomass pellet fuel prepared by the production process according to any one of claims 1 to 7, wherein the biomass pellet fuel comprises a biomass matrix, an internally doped mineral functional agent and a surface functional layer, wherein the biomass matrix is prepared from a coking polymer produced in the production process of furfural residues and furfural residues, the mass ratio of the coking polymer to the furfural residues is 2-5:95-98, the internally doped mineral functional agent is at least one of silica-alumina minerals, carbonate minerals and zeolite, the mass fraction of the internally doped mineral functional agent in the biomass pellet fuel is 0.5-5wt%, the surface functional layer comprises a mineral protective layer and/or a hydrophobic shell layer, the content of the mineral protective layer is 0.2-2wt% (in terms of solids) and/or the content of the hydrophobic shell layer is 0.2-2.0wt% in terms of the mass of particles, when the surface functional layer simultaneously comprises the mineral protective layer and the hydrophobic shell layer, the surface functional layer is a nuclear-mineral layer-hydrophobic layer structure and the mineral layer is inside the hydrophobic layer, the diameter of the biomass pellet fuel is 5-20 kg, the length of the pellet fuel is less than 15 kg/3000 kg, and the calorific value of the pellet fuel is less than 15 kg/3000 kg.

Description

Production process for low-temperature drying extrusion of furfural residues to prepare biomass particles Technical Field The invention relates to the technical field of biomass briquette preparation, in particular to a production process for extruding biomass particles by drying furfural residues at a low temperature. Background The biomass granular fuel is generally prepared from agriculture and forestry residues, industrial byproducts or organic solid wastes through the procedures of drying, crushing/mixing, extrusion molding, cooling and screening and the like, and can be used for residential heating, industrial heating and other scenes. The existing production line mostly adopts a process route of a roller dryer matched with a fan for dehumidification, a granulator for extrusion molding and a screening return material, so as to obtain certain molding strength and flammability and realize large-scale continuous production. However, for materials such as furfural residue, xylose residue, vinasse, cow dung and the like, the characteristics of high water content, tiny particles, higher ash content and large physical fluctuation generally exist, so that the stability of the traditional process in engineering operation is insufficient. Taking furfural slag as an example, the initial water content of the furfural slag can reach 50-60%, the furfural slag is acidic and entrains fine ash and fine particles, coking polymer byproducts are also generated in the operation process of the furfural device, the shape, ash and combustion characteristics of the coking polymer byproducts and the furfural slag are greatly different, and the superposition of the factors makes the fluctuation of raw materials more sensitive to the influence of drying, classification and forming links. In the prior art, a scheme for preparing granular fuel by using furfural residue is disclosed, for example, patent document No. CN105018178a discloses a process for preparing plant granules by using furfural residue. The scheme realizes the recycling of the furfural residue to a certain extent, but some schemes are for improving the forming or heat value performance, substances such as potassium permanganate, kitchen waste grease, magnesium powder and the like are introduced or multiple materials are adopted to be mixed in a complex mode, the problems of safety risk, raw material compliance and cost rise are possibly caused, meanwhile, the proportion and fluctuation of the multiple raw materials also easily cause unstable particle heat value, ash content and appearance quality, and the patent document number CN105482867B comprises the steps of sieving/crushing, water spraying and humidity control (for example, the water content is controlled to be 9-13%), stacking fermentation, forming, natural airing and dewatering and the like. The scheme can realize the fuelization utilization of the furfural residue, but is dependent on links such as multi-material proportioning, fermentation, natural airing and the like, is easily influenced by raw material fluctuation and environmental conditions, is relatively limited in continuous and quality stable control, and can bring about constraint in the aspects of consistency of ingredient management and product composition due to the introduction of additional components such as lime powder, and the like, and the patent document No. CN120521219A focuses on making the furfural residue meet the requirements of treatment before blending combustion, has a certain process control and energy recovery thought, and has a certain defect in the aspects of continuous and stable preparation of molded fuel particles and improvement of storage and transportation performance. There have also been "multi-layer structure/cladding structure" schemes surrounding biomass briquette fuels, for example, patent document No. CN111019730a/B, which adopts a hierarchical structure such as inner core/control layer/shell layer, and introduces inorganic components such as bentonite, bone powder, fly ash, lime powder, etc. into different layers to achieve regulation of combustion process and heat release stability, focusing on improving combustion stability and combustion rhythm by functional layer formulation. In addition, the utility model field also has a scheme for reducing problems such as coking and sticking through a structure level, for example, the composite biomass particles disclosed in CN207862279U adopt an inner and outer composite structure to improve the coking/sticking problem in the use process. Meanwhile, a structural improvement scheme of coated biomass particles (patent document number CN207862927U, CN207862281U and the like belong to the thinking) also exists, and the technology belongs to the multi-layer/coating direction as well as the technical path of piling adhesion and transportation abrasion powder dropping by adopting the design of a multi-deflection combustion control layer or a structural composite layer, which