Method for improving quality and efficiency of lignite through full-physical biological extraction and high-temperature flash evaporation

Abstract

The invention relates to an all-physical biological extraction and high-temperature flash evaporation lignite quality and effect improving method which comprises the following steps: step 1, crushing lignite raw materials to 60-100 meshes, and mechanically squeezing to remove surface moisture and destroy a void structure; an oxidizing agent is adopted for catalytic oxidation pretreatment to destroy the macromolecular structure of lignite and improve the subsequent extraction efficiency; 2, mixing the crushed and catalytically oxidized lignite with microorganisms in an oxidation tank or mixing the lignite with an enzyme preparation in an enzymolysis tank, and then enabling the mixture to enter a catalytic reaction kettle to react for 24-72 hours at the temperature of 30-50 DEG C; and step 3, in a closed reaction system, introducing high-temperature flue gas of 800-1100 DEG C, adding the lignite powder treated in the step 2, and maintaining for 5-15 seconds under the condition that the pressure is-0.2 to-0.8 MPa. The method has the beneficial effects that high-efficiency pulverized coal, humic acid fertilizer and mineral biostimulant can be produced, the recycling and high-value utilization of lignite is realized, and the method has the advantages of environmental protection, high efficiency and poly-generation, and is suitable for the fields of energy, agriculture and chemical industry.

Description

Technical Field

[0001] The invention relates to the technical field of efficient utilization of lignite resources, and in particular to a method for improving the quality and efficiency of lignite by full physical biological extraction and high-temperature flash evaporation. Background Art

[0002] As a low-grade coal, lignite has a high water content (30% to 50%) and a low calorific value (about 8.82MJ / kg). Its direct combustion efficiency is low and it causes great pollution. Traditional quality improvement technologies mostly rely on chemical solvents or high-temperature pyrolysis, which have problems such as high energy consumption, heavy pollution, and single products. In recent years, physical and biological synergistic technologies have become a research hotspot. For example, the high-temperature flash evaporation process achieves efficient removal of water and volatiles through rapid pressure reduction, but it is not combined with biological extraction, and the resource utilization rate is low. The humic acid extraction process mostly uses alkali solution or oxidant, but the chemical residue affects the purity of the product and is not integrated with the quality improvement process; the mechanical activation process only improves the combustion performance through physical crushing, and does not activate the biologically active components in lignite.

[0003] Based on the shortcomings of the prior art, the motivation for the invention is to provide a new method for improving the quality and efficiency of lignite by full physical biological extraction and high-temperature flash evaporation. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a novel method for improving the quality and efficiency of lignite by full physical biological extraction and high-temperature flash evaporation. The full physical biological extraction technology based on mechanical physical activation, catalytic oxidation, negative pressure cracking, high-temperature flash evaporation and other technologies and processes realizes a comprehensive utilization method for improving the quality and efficiency of lignite, and can simultaneously produce a variety of high-value-added products such as high-efficiency coal powder, humic acid, and mineral-derived biostimulants.

[0005] The method for improving the quality and efficiency of lignite by full physical biological extraction and high-temperature flash evaporation provided by the present invention has the following technical solutions:

[0006] A method for improving the quality and efficiency of lignite by full physical biological extraction and high-temperature flash evaporation, comprising the following steps:

[0007] Step 1: Mechanical and physical activation and lignite pretreatment

[0008] The lignite raw material is crushed into 60-100 meshes, and the surface moisture is removed by mechanical pressing to destroy the pore structure; the oxidant is used for catalytic oxidation pretreatment to destroy the lignite macromolecular structure and improve the subsequent extraction efficiency;

[0009] Step 2: Full physical biological extraction

[0010] Mix the crushed and catalytically oxidized lignite with microorganisms in an oxidation tank or with an enzyme preparation in an enzymatic hydrolysis tank, and then enter a catalytic reaction kettle to react at 30-50 °C for 24-72 hours; separate the solid and liquid phases through a centrifugal separation device: the separated solid phase is high-efficiency pulverized coal, which is used for power generation in coal-fired power plants; the liquid phase is used to extract humic acid, fulvic acid and organic acid substances.

[0011] Step three: High-temperature flash evaporation for quality improvement

[0012] In a closed reaction system, introduce high-temperature flue gas at 800-1100 °C and input the lignite powder treated in step two, and maintain it for 5-15 seconds under the condition of a pressure of -0.2 to -0.8 MPa; high-temperature flash evaporation is carried out under negative pressure conditions to instantaneously evaporate moisture and light volatile components, and the volatile components are condensed and recovered for use in synthesizing biostimulants or fine chemicals.

[0013] Furthermore, it also includes step four: Preparation of mineral source biostimulants and soil conditioners

[0014] The humic acid extract obtained by condensing the volatile components in step three is concentrated at low temperature and added with the liquid phase extract obtained in step two and compounded with medium and trace elements to prepare a mineral source biostimulant with a pH of 5.0-6.0, which is used for soil improvement or foliar fertilizer.

[0015] After high-temperature negative-pressure pyrolysis, lignite becomes a multi-porous structure, which is rich in organic matter and humic acid, and is used for producing soil conditioners to promote crop growth and repair polluted soil.

[0016] Furthermore, in step one, the lignite raw material is crushed by a jaw crusher and then enters a multi-stage pair-roll crusher for squeezing and pulverizing to 60-100 meshes, changing the internal microstructure of lignite under high pressure to achieve mechanical physical activation. Then the lignite is sent to a raw material buffer bin by a bucket elevator, and the treated lignite raw material enters a flash evaporation device containing an oxidant from the raw material buffer bin for depolymerization extraction, and then enters an activated high-temperature pyrolysis furnace to break the macromolecular structure of lignite to complete the pretreatment.

[0017] 4. A method for improving the quality and efficiency of lignite by all-physical biological extraction and high-temperature flash evaporation according to claim 1, wherein: in step one, the oxidant is H2O2.

[0018] Furthermore, in step two, a temperature control and stirring system is built in the oxidation tank and the enzymatic hydrolysis tank, and a microbial community activity monitoring module is equipped.

[0019] Furthermore, in step two, after the lignite reacts in the catalytic reaction kettle, it enters another enzymatic hydrolysis tank, and then reacts in an extraction reaction kettle and then enters a centrifugal separation device to separate the solid and liquid phases.

[0020] Further, in Step 2, the microorganism is a lignin-degrading bacterium, the particle size of the solid-phase high-efficiency pulverized coal is <0.075 mm, and the purity of the extracted humic acid is ≥50%.

[0021] Further, in Step 3, the calorific value of the lignite after high-temperature flash evaporation is increased to 16.38 - 16.76 MJ / kg, and the moisture content is reduced to 5% - 12%, realizing the transformation of lignite from fuel to raw material and enhancing the economic value.

[0022] Further, in Step 3, the lignite powder after being treated in Step 2 enters the high-temperature negative-pressure cyclone extraction device through a lock-hopper feeder. After high-temperature flash evaporation, the lignite powder enters the coarse powder separator with the air duct to separate the lignite, and the finer pulverized coal passes through the cyclone dust collector and bag filter in sequence under the action of the induced draft fan to obtain the ultra-fine high-efficiency lignite powder.

[0023] Further, in Step 3, the cyclone extraction device is integrated with a pressure sensor, a temperature control system and an automatic pressure relief valve, supporting rapid pressure reduction and regulating cracking conditions; by adjusting the flash evaporation speed and pressure change, the composition ratio of volatile components can be adjusted, and after the subsequent solid-liquid separation, the volatile components are condensed and recovered.

[0024] The implementation of the present invention includes the following technical effects:

[0025] The method for improving the quality and efficiency of lignite by all-physical biological extraction and high-temperature flash evaporation of the present invention removes moisture and volatile components by high-temperature flash evaporation, combines all-physical biological extraction technology to extract humic acid and organic active components, and uses mechanical activation to enhance the reaction activity of lignite. Finally, high-efficiency pulverized coal, humic acid fertilizer and mineral source biological stimulants are produced, realizing the resource-based and high-value utilization of lignite. The present invention has the advantages of environmental protection, high efficiency and multi-cogeneration, and is applicable to the fields of energy, agriculture and chemical industry. Description of the Drawings

[0026] Figure 1 It is a schematic flow chart of the method for improving the quality and efficiency of lignite by all-physical biological extraction and high-temperature flash evaporation according to the embodiment of the present invention. Detailed Embodiment

[0027] The present invention will be described in detail below in conjunction with the embodiments and the drawings. It should be noted that the described embodiments are only for facilitating the understanding of the present invention and do not limit it in any way.

[0028] See Figure 1 As shown, a method for improving the quality and efficiency of lignite by all-physical biological extraction and high-temperature flash evaporation in this embodiment includes the following steps:

[0029] Step 1: Mechanical physical activation and lignite pretreatment

[0030] The raw materials are crushed to 60 - 100 mesh, and mechanically pressed to remove surface moisture and destroy the pore structure; catalytic oxidation pretreatment is carried out using an oxidant (H2O2) to break the macromolecular structure of lignite and improve the subsequent extraction efficiency; specifically, the lignite raw materials are crushed by a jaw crusher and then enter a multi-stage pair-roll crusher for pressing and crushing to 60 - 100 mesh, changing the internal microstructure of lignite under high pressure to achieve mechanical physical activation. After that, the lignite is sent to the raw material buffer bin by a bucket elevator, and the treated lignite raw materials then enter a flash evaporation device containing an oxidant for depolymerization extraction, and then enter an activated high-temperature cracking furnace to break the macromolecular structure of lignite, completing the pretreatment.

[0031] Step 2: All-physical biological extraction

[0032] The crushed and catalytically oxidized lignite is mixed with microorganisms (such as lignin-degrading bacteria) in an oxidation tank or with an enzyme preparation in an enzymatic hydrolysis tank, and then enters a catalytic reaction kettle for reaction at 30 - 50 °C for 24 - 72 hours; the solid-liquid two phases are separated by a centrifugal separation device: the separated solid phase is high-efficiency pulverized coal (particle size < 0.075 mm), which is used for power generation in coal-fired power plants; the liquid phase is used to extract humic acid (purity ≥ 50%), fulvic acid and organic acid substances; specifically, a temperature control and stirring system is built into the oxidation tank and the enzymatic hydrolysis tank, and a microbial community activity monitoring module is equipped. Preferably, after the lignite reacts in the catalytic reaction kettle, it enters another enzymatic hydrolysis tank, and then reacts in an extraction reaction kettle and then enters the centrifugal separation device to separate the solid-liquid two phases. This step makes the enzymatic hydrolysis and reaction more complete.

[0033] Step 3: High-temperature flash evaporation for quality improvement

[0034] In a closed reaction system, high-temperature flue gas at 800 - 1100 °C is introduced and the lignite pulverized coal treated in Step 2 is put in. Under the condition of a pressure of -0.2 - -0.8 MPa, it is maintained for 5 - 15 seconds; high-temperature flash evaporation is carried out under negative pressure conditions, so that moisture and light volatile components (such as small molecule organic acids, phenols) are instantaneously evaporated, and the volatile components are condensed and recovered for use in synthesizing biological stimulants or fine chemicals; the calorific value of the lignite after high-temperature flash evaporation is increased to 16.38 - 16.76 MJ / kg, and the moisture content is reduced to 5% - 12%, realizing the transformation of lignite from fuel to raw material and enhancing the economic value. Specifically, the lignite pulverized coal treated in Step 2 enters a high-temperature negative-pressure cyclone extraction device through a lock hopper feeder. After high-temperature flash evaporation, the lignite pulverized coal enters a coarse powder separator with the air duct to separate the lignite, and the finer pulverized coal passes through a cyclone dust collector and a bag filter in sequence under the action of an induced draft fan to obtain high-efficiency lignite pulverized coal. The cyclone extraction device integrates a pressure sensor, a temperature control system and an automatic pressure relief valve, supporting rapid pressure reduction and regulation of cracking conditions. By adjusting parameters such as the flash evaporation speed and pressure change, the composition ratio of the volatile components can be adjusted. After passing through the subsequent solid-liquid separation and condensing and recovering the volatile components, high-purity extracts are obtained.

[0035] Step 4: Preparation of Mineral Source Biological Stimulant and Soil Conditioner

[0036] The humic acid extract obtained by condensing the volatile matter in Step 3 is concentrated at low temperature and added with the liquid phase extract (humic acid) and compound medium and trace elements (calcium, magnesium, sulfur) in Step 2 to prepare a mineral source biological stimulant with a pH of 5.0 - 6.0, which is used for soil improvement or foliar fertilizer.

[0037] Lignite becomes a multi-porous structure after high-temperature negative-pressure cracking. It is rich in organic matter and humic acid, and is used to produce soil conditioners, promote crop growth and repair polluted soil. Its strong adsorption property can adsorb heavy metal ions, repair polluted soil, and at the same time has good fertilizer and water retention effects.

[0038] The method of this embodiment has the following technical advantages:

[0039] Comprehensive utilization of resources: The utilization rate of lignite > 90%, and multiple products such as fuel, humic acid, biological stimulant, soil conditioner and chemical raw materials are produced. It not only improves the quality of lignite, but also extracts useful chemical components and increases economic benefits;

[0040] Economy: The extraction cost of humic acid is reduced by 30%, and the mineral source biological stimulant can replace 10% - 20% of traditional chemical fertilizers.

[0041] Environmental protection: Less chemical solvents are used throughout the process, and harmful gases (H2S, NH3) are treated through centralized ventilation;

[0042] Wide application range: Applicable to lignite of different qualities.

[0043] To better illustrate the technical solution of the present invention, two embodiments of "preparation of high-efficiency pulverized coal" and "co-production of humic acid and biological stimulant" are described.

[0044] Example 1: Preparation of High-Efficiency Pulverized Coal

[0045] Take Inner Mongolia lignite (moisture content 45%), crush it to 80 mesh, and perform multi-stage crushing and catalytic oxidation (H2O2) treatment; after biological extraction, the solid phase is subjected to high-temperature flash evaporation (1000 °C, -0.3 MPa, 15 seconds), and then airflow pulverization. After classification by quality, ultrafine high-efficiency lignite powder (D90 < 75 μm) is obtained, which meets the direct combustion requirements of power plants, cement plants, etc. After high-temperature flash evaporation, the moisture content drops to 12%, and the calorific value reaches 16.5 MJ / kg.

[0046] Example 2: Co-Production of Humic Acid and Biological Stimulant

[0047] Take Inner Mongolia lignite (with a moisture content of 45%), crush it to 80 mesh, and subject it to multi-stage crushing and catalytic oxidation (H2O2) treatment; after activation, mix the lignite with lignin-degrading bacteria (*Phanerochaete chrysosporium*), react at 40 °C for 48 hours, and extract humic acid through alkali and acid; after centrifugal separation, concentrate the liquid phase by rotary evaporation until the solid content of humic acid reaches 50%, add medium and trace elements (calcium, magnesium, sulfur, boron, zinc) and pH regulators, such as magnesium sulfate, calcium nitrate, boron, zinc, molybdenum, etc. can be selectively added, to produce ore-source humic acid; the pH of the product is 5.8, the humic acid content is ≥55%, and field tests show a 12% increase in crop yield. After centrifugal separation, the solid phase is subjected to high-temperature flash evaporation to extract the volatile matter in the solid phase. The volatile matter is collected by condensation at the back end, and medium and trace elements (calcium, magnesium, sulfur, boron, zinc) and pH regulators, such as magnesium sulfate, calcium nitrate, boron, zinc, molybdenum, etc. can be selectively added, to produce a biostimulant.

[0048] The method for improving the quality and efficiency of lignite by all-physical biological extraction and high-temperature flash evaporation of the present invention organically combines technologies such as mechanical physical activation, catalytic oxidation, all-physical biological extraction, high-temperature flash evaporation dehydration, and negative-pressure cracking to achieve multi-stage fractional utilization of lignite and synchronously produce fuels, chemical raw materials, and agricultural materials.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for improving the quality and efficiency of lignite by full physical biological extraction and high-temperature flash distillation, characterized in that: The following steps are involved: Step 1: Mechanical and physical activation and lignite pretreatment The lignite raw material is crushed to 60-100 mesh, and mechanically pressed to remove surface moisture and destroy the pore structure; Use oxidant catalytic oxidation pretreatment to destroy the macromolecular structure of lignite and improve subsequent extraction efficiency; Step 2: Full physical biological extraction The crushed and catalytically oxidized lignite is mixed with microorganisms in an oxidation tank or with enzyme preparations in an enzymatic hydrolysis tank, and then placed in a catalytic reactor to react at 30-50°C for 24-72 hours; the solid and liquid phases are separated by a centrifugal separation device: the separated solid phase is high-efficiency lignite powder; the liquid phase is used to extract humic acid, fulvic acid and organic acid substances; Step 3: High temperature flash evaporation In a closed reaction system, high-temperature flue gas of 800 to 1100°C is injected and the lignite powder treated in step 2 is added, and the pressure is maintained at -0.2 to -0.8 MPa for 5 to 15 seconds; high-temperature flash evaporation is carried out under negative pressure conditions to evaporate water and light volatiles instantly, and the volatiles are condensed and recovered for the synthesis of biostimulants or fine chemicals.

2. The method for improving the quality and efficiency of lignite by full physical biological extraction and high temperature flash distillation according to claim 1, characterized in that: Also includes step 4: preparation of mineral-derived biostimulants and soil conditioners The humic acid extract obtained by condensing the volatile matter in step 3 is concentrated at low temperature and added with the liquid extract obtained in step 2 and compounded trace elements to prepare a mineral-derived biostimulant with a pH of 5.0 to 6.0 for soil improvement or foliar fertilizer; After high-temperature negative pressure cracking, lignite becomes a porous structure rich in organic matter and humic acid, which is used to produce soil conditioners, promote crop growth and repair contaminated soil.

3. The method for improving the quality and efficiency of lignite by full physical biological extraction and high temperature flash distillation according to claim 1, characterized in that: In step one, the lignite raw material is crushed by a jaw crusher and then sent to a multi-stage roller crusher to be pressed and crushed to 60-100 meshes, and the internal microstructure of the lignite is changed under high pressure to achieve mechanical and physical activation. After that, the lignite is sent to a raw material buffer bin via a bucket elevator. The treated lignite raw material then enters a flash evaporation device containing an oxidant from the raw material buffer bin for depolymerization and extraction, and then enters an activated high-temperature cracking furnace to destroy the lignite macromolecular structure, thereby completing the pretreatment.

4. The method for improving the quality and efficiency of lignite by full physical biological extraction and high temperature flash distillation according to claim 1, characterized in that: In step 1, the oxidant is H2O2.

5. The method for improving the quality and efficiency of lignite by full physical biological extraction and high temperature flash distillation according to claim 1, characterized in that: In step 2, a temperature control and stirring system is built into the oxidation tank and the enzymatic hydrolysis tank, and a bacterial activity monitoring module is provided.

6. The method for improving the quality and efficiency of lignite by full physical biological extraction and high temperature flash distillation according to claim 1, characterized in that: In step 2, the lignite enters another enzymatic hydrolysis tank after reacting in the catalytic reactor, and then enters a centrifugal separation device to separate the solid and liquid phases after reacting in the extraction reactor.

7. The method for improving the quality and efficiency of lignite by full physical biological extraction and high temperature flash distillation according to claim 1, characterized in that: In step 2, the microorganism is a lignin-degrading bacterium, the particle size of the solid-phase high-efficiency coal powder is less than 0.075 mm, and the purity of the extracted humic acid is ≥50%.

8. The method for improving the quality and efficiency of lignite by full physical biological extraction and high temperature flash distillation according to claim 1, characterized in that: In step three, the calorific value of the lignite after high-temperature flash evaporation is increased to 16.38-16.76 MJ / kg, and the moisture content is reduced to 5%-12%, thereby realizing the transformation of lignite from fuel to raw material and improving its economic value.

9. The method for improving the quality and efficiency of lignite by full physical biological extraction and high temperature flash distillation according to claim 1, characterized in that: In step three, the lignite powder treated in step two enters a high-temperature negative pressure cyclone extraction device through an air-locking feeder. After high-temperature flash evaporation, the lignite powder enters a coarse powder separator through an air duct to separate the lignite. The finer coal powder passes through a cyclone dust collector and a bag dust collector in turn under the action of an induced draft fan to obtain ultrafine and efficient lignite powder.

10. The method for improving the quality and efficiency of lignite by full physical biological extraction and high temperature flash distillation according to claim 1, characterized in that: In step three, the cyclone extraction device integrates a pressure sensor, a temperature control system and an automatic pressure relief valve to support rapid pressure reduction and regulation of cracking conditions; the composition ratio of the volatile matter can be adjusted by adjusting the flash evaporation rate and pressure changes, and the volatile matter is recovered by condensation after solid-liquid separation at the back end.

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