Biomass-cooperated liquid-state deslagging method for household garbage gasification furnace

Abstract

The invention belongs to the technical field of harmless treatment of garbage, and particularly relates to a biomass-synergistic household garbage gasifier liquid-state deslagging method which comprises the following steps: component determination: respectively determining ash components of household garbage ash and ash components of biomass ash; fluxing agent selection: selecting one biomass or a biomass mixture obtained by mixing at least two biomasses as a biomass fluxing agent according to ash components of the household garbage ash and the biomass ash; and gasification reaction: mixing the household garbage and the biomass fluxing agent, carrying out gasification reaction on the obtained mixture, and discharging ash. According to the method, the heat value of the gasification raw material is guaranteed, and the FT temperature of the household garbage gasification reaction ash is reduced, so that the requirement for the reaction temperature is reduced, the energy consumption of equipment operation is reduced, the equipment operation cost is reduced, meanwhile, the temperature interval is expanded, the fluctuation temperature of a slag discharging opening is met, smooth liquid slag discharging is achieved, and the equipment operation stability is improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of harmless treatment of garbage, and particularly relates to a method for liquid slagging of a biomass-collaborative household garbage gasifier. BACKGROUND

[0002] City household garbage refers to solid waste generated in various activities in daily life of a city, and has the characteristics of wide source, large total amount and complex composition. High-temperature gasification technology can well realize cleaner resource utilization of household garbage. In the high-temperature gasification process, household garbage will decompose to generate synthesis gas such as CO and H2, and organic matters (dioxin, furan, etc.) will further decompose under the action of high temperature, and the inorganic matters remaining after the reaction are converted into glass, so that the reduction of household garbage is realized, and secondary pollution of household garbage is avoided and resource utilization of household garbage is realized, that is, the substances and energy in household garbage are re-introduced into the ecological recycling utilization system.

[0003] At present, high-temperature gasifiers such as space furnace, Tsinghua furnace, East furnace, Jinhang furnace and BGL (British Gas-Lurgi gasifier) adopt a slagging mode of liquid slagging, which improves the requirement for raw materials to a certain extent. Household garbage ash has a high Ca content (> 50%) and a low Si content. Excessive Ca will not only react with the low content of Al in household garbage ash to generate calcium aluminate CaAl2O4 (melting point 1600℃) with a high melting point, but also form CaO (melting point 2572℃). Therefore, the flow temperature of household garbage ash is relatively high, far greater than 1500℃. To realize liquid slagging of household garbage ash, two ways can be theoretically adopted: one is to produce household garbage gasification at an operating temperature higher than 1600℃, but this will undoubtedly increase the energy consumption of equipment operation and increase the equipment operation cost; the other is to add inorganic flux to household garbage to reduce the ash melting point, and the addition of inorganic flux will cause the ash content in household garbage ash to surge, which greatly reduces the calorific value of the raw material. SUMMARY

[0004] The present application aims to provide a method for liquid slagging of a biomass-collaborative household garbage gasifier to solve the above technical problems.

[0005] In order to achieve the above-mentioned purpose, the present application adopts the following technical solutions: The application provides a method for liquid slagging of a biomass-assisted household garbage gasification furnace, comprising the following steps: component determination: respectively determining ash components of household garbage ash and ash components of biomass ash; fluxing agent selection: selecting one kind of biomass or a mixture of at least two kinds of biomass as a biomass fluxing agent according to the ash components of the household garbage ash and the ash components of the biomass ash; gasification reaction: mixing the household garbage and the biomass fluxing agent, and performing gasification reaction on the obtained mixture to discharge ash.

[0006] In some embodiments of the application, the ash components of the household garbage ash mainly include CaO, the ash components of the biomass ash mainly include SiO2, one kind of biomass or a mixture of at least two kinds of biomass is selected as the biomass fluxing agent according to the mass fraction of CaO in the ash components of the household garbage ash and the mass fraction of SiO2 in the ash components of the biomass ash, the mixing ratio of different biomasses in the mixture of the biomasses is adjusted, and the mixing ratio of the biomass fluxing agent and the household garbage in the gasification reaction step is adjusted, so that the mass ratio of CaO to SiO2 in the ash is less than 2.7.

[0007] In some embodiments of the application, the mass ratio of CaO to SiO2 in the ash is 0.5-1.8.

[0008] In some embodiments of the application, the mass ratio of CaO to SiO2 in the ash is 1.7, 1.6, 1.5, 1.4, 1.3, 1.2, 1.1, 1.0, 0.9, 0.8, 0.7, 0.6 or 0.5.

[0009] In some embodiments of the application, the biomass is an agricultural and forestry waste.

[0010] In some embodiments of the application, the agricultural and forestry waste is at least one of corn stalks, wheat stalks, corn cobs or rice husks.

[0011] In some embodiments of the application, the mass ratio of the biomasses in the biomass fluxing agent is corn stalks:wheat stalks:corn cobs:rice husks=(0-7):(0-2):(0-2):(0-2).

[0012] In some embodiments of the application, the biomass fluxing agent is selected from corn stalks, corn cobs and wheat stalks. In some embodiments of the application, the mass ratio of corn stalks to wheat stalks in the biomass fluxing agent is 0.5-3.5 or the mass ratio of corn stalks to corn cobs is 0.5-3.5.

[0013] In some embodiments of the application, the mass ratio of corn stalks to wheat stalks in the biomass fluxing agent is 1.5 or the mass ratio of corn stalks to corn cobs is 1.5.

[0014] In some embodiments of the present application, the component determination step further comprises a preparation step, ashing: ashing the household garbage and the biomass separately to obtain household garbage ash and biomass ash.

[0015] In some embodiments of the present application, the gasification reaction step comprises a homogenization treatment: crushing and sieving the household garbage and the biomass fluxing agent separately to obtain crushed household garbage and crushed biomass fluxing agent, crushing and sufficiently mixing the crushed household garbage and the crushed biomass fluxing agent to obtain homogenized material.

[0016] In some embodiments of the present application, the particle size of the crushed household garbage and the crushed biomass fluxing agent obtained by crushing and sieving the household garbage and the biomass fluxing agent in the homogenization treatment step is less than 0.2 mm. The particle size of the crushed household garbage and the crushed biomass fluxing agent is less than 0.2 mm to uniformly mix the crushed household garbage and the crushed biomass fluxing agent and avoid insufficient local reaction or coking in the subsequent gasification reaction process.

[0017] In some embodiments of the present application, the mixing method in the homogenization treatment step is mechanical mixing or pyrolysis mixing.

[0018] In some embodiments of the present application, the gasification reaction step further comprises a forming processing treatment: forming the homogenized material into fuel pellets by sieving or into fuel rods by pressing, and then feeding the fuel pellets or the fuel rods into a gasification furnace for gasification reaction.

[0019] In some embodiments of the present application, the particle size of the fuel pellets is less than 100 mesh. The particle size of the fuel pellets is less than 100 mesh to have a larger specific surface area, so that the homogenized material has a larger contact area with air, the reaction rate is accelerated during the gasification reaction, the gasification reaction is more complete, and the residual amount of household garbage ash is reduced.

[0020] In some embodiments of the present application, the gasification furnace comprises an entrained flow bed, a fluidized bed, and a fixed bed, and the fuel pellets or the fuel rods are fed into the entrained flow bed, the fluidized bed, or the fixed bed for gasification reaction.

[0021] In some embodiments of the present application, the fuel pellets are fed into the entrained flow bed or the fluidized bed for gasification reaction, and the fuel rods are fed into the fluidized bed or the fixed bed for gasification reaction.

[0022] In some embodiments of the present application, the device used for pressing and forming the fuel rods is a double-roll forming machine.

[0023] In some embodiments of the present application, the flow temperature of the ash is less than 1500℃.

[0024] The application provides a method for liquid slagging of a household garbage gasification furnace in cooperation with biomass, aiming at the characteristics of high calcium and low silicon in household garbage ash, and proposes to co-gasify high-silicon biomass, so as to reduce the melting temperature of household garbage ash at a lower loss of the calorific value of the gasification raw material, significantly reduce the flow temperature of household garbage ash, thereby reduce the requirement for the reaction temperature, reduce the energy consumption of equipment operation, reduce the equipment operation cost, expand the temperature interval, meet the fluctuation temperature of the slagging port, realize smooth liquid slagging, and increase the stability of equipment operation. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 A viscosity-temperature characteristic curve of household garbage is provided in the application.

[0026] Figure 2 A viscosity-temperature characteristic curve of ash slag is provided in Example 1 of the application.

[0027] Figure 3 A viscosity-temperature characteristic curve of ash slag is provided in Example 2 of the application.

[0028] Figure 4 A viscosity-temperature characteristic curve of ash slag is provided in Example 3 of the application.

[0029] Figure 5 A viscosity-temperature characteristic curve of ash slag is provided in Example 4 of the application.

[0030] Figure 6 A viscosity-temperature characteristic curve of ash slag is provided in Example 5 of the application. DETAILED DESCRIPTION

[0031] In the present application, the numerical range indicated by “~” means that the numerical value indicated before and after “~” is respectively taken as the minimum value and the maximum value of the range.

[0032] In the numerical range recorded in stages in the present application, the upper limit value or the lower limit value recorded in a certain numerical range can be replaced by the upper limit value or the lower limit value of other stages of the recorded numerical range. In the numerical range recorded in the present application, the upper limit value or the lower limit value recorded in a certain numerical range can be replaced by the value shown in the examples.

[0033] Unless the context clearly indicates otherwise, when used in the present specification, the term “comprise”, “include” or “contain” specifies the presence of the stated element, but does not exclude the presence or addition of one or more other elements.

[0034] In order to make the above objectives, features and advantages of the present application more apparent, more comprehensible, the specific embodiments of the present application are described in detail below with reference to the drawings. In the following description, a large number of specific details are set forth in order to provide a thorough understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the spirit of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0035] The method for biomass-coordinated liquid slagging of household garbage gasification furnace of the present application aims to solve the problems that the liquid slagging of household garbage gasification reaction process needs to be carried out at a high operating temperature, increasing the energy consumption of equipment operation and the operating cost of equipment, and that the additional addition of inorganic flux is needed to reduce the melting temperature of household garbage ash, but will cause the ash content in household garbage ash to surge, greatly reducing the calorific value of raw materials.

[0036] The household garbage of the present application refers to solid waste generated in daily life or activities providing services for daily life, and solid waste regarded as household garbage by laws and administrative regulations. It mainly includes household garbage, market trade and commercial garbage, public place garbage, street cleaning garbage and enterprise and institution garbage, etc.

[0037] In the embodiments of the present application, the flow temperature (FT) of the household waste ash is determined by an ash fusibility tester, the flow temperature of the ash is determined according to the national standard “GB / T 219-2008 Determination of Ash Fusibility”, the prepared triangular ash cone is placed in the ash fusion tester, the temperature is raised from room temperature to 900℃ at a rate of 15℃ / min, and then the temperature is continuously raised at a rate of 5℃ / min until 1500℃, the corresponding melting temperature is observed and recorded according to the change of the shape of the ash cone, the melting temperature includes: deformation temperature (DT), softening temperature (ST), hemisphere temperature (HT), flow temperature (FT), the flow temperature refers to the critical temperature at which the mixture (such as ash) begins to have obvious fluidity during heating. The high-temperature viscosity curve of the household waste ash is determined by a high-temperature viscometer, the molten slag flow condition of the gas flow bed is simulated, the ash sample is placed in a high-temperature electric furnace for pre-melting, the pre-melting temperature is 100℃-200℃ higher than the ash flow temperature, the crucible is taken out after natural cooling to room temperature and broken, the ash slag is obtained, and the obtained ash slag is subjected to viscosity test, the viscosity test process includes the following steps: (1) 50-55g of ash sample is placed in the test crucible, placed on the viscometer support and then covered with a corundum protection tube; (2) turn on the vacuum pump switch, turn off the exhaust switch and the air inlet switch, and pump for about 5 minutes, when the vacuum gauge shows that the pressure is close to-0.1MPa, turn off the vacuum pump; (3) introduce the required atmosphere (air atmosphere, weak reducing atmosphere), and the flow rate is controlled at 100ml / min; (4) set the temperature rising program and start heating, when the sample reaches the highest set temperature (pre-melting temperature), the rotor is placed in the sample and the cooling test is started, and the cooling rate is 2℃ / min; (5) the computer automatically records the temperature and viscosity; (6) after the test is completed, the rotor is taken out of the liquid surface according to the instrument prompt, and the high-temperature furnace continues to cool to room temperature. According to the recorded temperature and viscosity, the high-temperature viscosity curve is drawn, and the temperature when the viscosity of the ash slag meets the industry standard system of 2.5-25Pa·s is obtained.

[0038] The method for the biomass-coordinated liquid slagging of the household waste gasification furnace provided in the embodiments of the present application includes the following steps, Component determination: respectively determine the ash components of the household waste ash and the ash components of the agricultural and forestry waste ash; The flux is selected according to the ash components of the household garbage ash and the agroforestry waste ash, and a biomass mixture of one agroforestry waste or at least two agroforestry wastes is selected as the biomass flux; in the embodiments of the present application, the specific agroforestry waste is selected from corn stalks, wheat stalks, corn cobs and rice husks, and the mass ratio of each component in the biomass flux is corn stalks:wheat stalks:corn cobs:rice husks=(0-7):(0-2):(0-2):(0-2); in some embodiments of the present application, the specific agroforestry waste is selected from corn stalks, wheat stalks and corn cobs, and the mass ratio of corn stalks:wheat stalks in the biomass flux is 0.5-3.5 or the mass ratio of corn stalks:corn cobs is 0.5-3.5; in some embodiments of the present application, the mass ratio of corn stalks:wheat stalks in the biomass flux is 1.5 or the mass ratio of corn stalks:corn cobs is 1.5.

[0039] The gasification reaction is performed on the mixture of the household garbage and the biomass flux, and the ash residue is discharged.

[0040] The component determination step further includes the following preparation step, The ashing treatment is performed on the household garbage and the agroforestry waste respectively to obtain the household garbage ash and the agroforestry waste ash.

[0041] The gasification reaction step further includes the following steps, The homogenization treatment is performed on the household garbage and the biomass flux respectively to obtain the crushed household garbage and the crushed biomass flux, and the crushed household garbage and the crushed biomass flux are crushed again and mixed thoroughly to obtain the homogenized material. In the embodiments of the present application, the particle size of the crushed household garbage and the crushed biomass flux obtained after the household garbage and the biomass flux are crushed and sieved is less than 0.2 mm, and the crushed biomass flux is mixed with the crushed household garbage at a blending ratio of 30%, 40%, 50%, 60% and 70% by mass fraction, and the thorough mixing is performed by mechanical mixing or pyrolysis mixing.

[0042] The forming processing treatment is performed on the homogenized material to form fuel pellets or fuel rods by sieving or by pressing, and then the fuel pellets or the fuel rods are sent into a gasification furnace for gasification reaction. In the embodiments of the present application, the particle size of the fuel pellets is less than 100 mesh, and the gasification furnace includes an entrained flow bed, a fluidized bed and a fixed bed, and the fuel pellets or the fuel rods are sent into the entrained flow bed, the fluidized bed or the fixed bed for gasification reaction.

[0043] The ash components of the household garbage ash in the component determination step mainly include CaO, and the ash components of the agricultural and forestry waste ash mainly include SiO2. According to the mass fraction of CaO in the ash components of the household garbage ash, one agricultural and forestry waste or a mixture of at least two agricultural and forestry wastes is selected as the biomass fluxing agent in the fluxing agent selection step, the mixing ratio of different agricultural and forestry wastes in the mixture of agricultural and forestry wastes is adjusted, and the mixing ratio of the biomass fluxing agent and the household garbage in the gasification reaction step is adjusted, so that the mass ratio of CaO to SiO2 in the ash slag is less than 2.7. In the embodiments of the present application, the mass ratio of CaO to SiO2 in the ash slag is 0.5-1.8; preferably, the mass ratio of CaO to SiO2 in the ash slag is 1.7, 1.6, 1.5, 1.4, 1.3, 1.2, 1.1, 1.0, 0.9, 0.8, 0.7, 0.6 or 0.5. Based on the promoting effect of the high content of SiO2 in the agricultural and forestry waste on the melting point of the high content of CaO in the household garbage, the appropriate amount of SiO2 is added to promote the reaction of the high melting point CaO in the household garbage with the SiO2 in the biomass to generate a low melting point calcium silicate salt. In addition, the agricultural and forestry waste also contains alkali metal oxides (such as Na2O, MgO and K2O), and the melting point of the alkali metal oxides is generally low, which can be melted to form liquid slag at a relatively low temperature (700-1200°C). In particular, the melting point of K2O is 770°C, and the low melting point K2O can destroy the crystal lattice structure of the high melting point CaO in the household garbage, promote the formation of a multi-component eutectic body with itself, and reduce the overall melting temperature, thereby achieving the effect of low-temperature eutectic.

[0044] According to the above steps, the agricultural and forestry waste is added to the household garbage to obtain a homogenized material. Although the content of K2O in the ash slag can be increased, the melting temperature of the household garbage during the gasification reaction can be reduced, but the content of SiO2 in the ash slag is also increased. The appropriate amount of SiO2 promotes the reaction of the high melting point CaO in the household garbage with the SiO2 in the biomass to generate a low melting point calcium silicate salt. Excessive SiO2 will react with the high melting point CaO in the household garbage to generate a high melting point mineral, so that the melting temperature of the household garbage during the gasification reaction shows a downward trend first and then an upward trend. Therefore, in the case of a known amount of household garbage, the key is to control the amount of SiO2 in the added agricultural and forestry waste, so that the mass ratio of CaO to SiO2 in the ash slag can achieve the purpose of reducing the melting temperature of the household garbage during the gasification reaction.

[0045] The compositions of household garbage ash, corn stalk ash, corn cob ash, and wheat stalk ash are determined according to the national standard “GB / T30725-2014 Determination of ash composition of solid biomass fuel”. The results are shown in Table 1. (The various elements in the ash may exist in the form of oxides, eutectics, etc. in the ash, and the ash composition detected by the national standard is actually the content of various ions, but the content of various components in the ash composition is usually represented in the form of various element ion oxides.) The household garbage is incinerated to obtain household garbage ash, and the composition of the household garbage ash mainly includes CaO, SiO2, Al2O3, TiO2, K2O, Na2O, Fe2O3, MgO, P2O5, and SO3. The mass fraction of CaO in the household garbage ash (especially the ash after incineration) is more than 50%. The biomass (such as agricultural and forestry waste) is incinerated to obtain biomass ash, and the biomass ash is rich in SiO2, Al2O3, Fe2O3, MgO, and K2O, and the mass fractions of SiO2 and K2O are both more than 30%. Agricultural and forestry waste is an important component of biomass, and it has the characteristics of high silicon and high alkali metal. Household garbage has the characteristic of high calcium. By adding agricultural and forestry waste to household garbage, silicon reacts with calcium to generate low-melting-point substances and alkali metal oxides, which promotes low-temperature eutectic, reduces the FT temperature of the ash, and improves the viscosity-temperature characteristic curve of the ash.

[0046] The present application proposes a liquid slagging method for household garbage ash based on biomass fluxing, to reduce the FT temperature of the ash and improve the viscosity-temperature characteristic curve of the ash, according to the complex and variable characteristics of the composition of household garbage ash. Specifically, on the one hand, the high-silicon (SiO2) biomass ash has a promoting effect on the regulation of the melting point of high-calcium (CaO) garbage ash. The appropriate addition of SiO2 promotes the reaction of CaO (melting point 2572℃), Ca2SiO4 (melting point 2130℃), and SiO2 (melting point 1713℃) to generate low-melting-point calcium silicates, such as Ca3Si2O7 (melting point 1458℃) and CaSiO3 (melting point 1540℃). At the same time, SiO2 also reacts with calcium aluminate CaAl2O4 (melting point 1600℃) to generate calcium aluminosilicate with a relatively lower melting point, such as CaAl2Si2O8 (melting point 1553℃), further reducing the melting point of high-calcium household garbage ash. On the other hand, based on the fact that alkali metal oxides and corresponding alkali metal silicates generally have a relatively low melting point and can melt to form liquid slag at a relatively low temperature (700℃-1200℃), low-melting-point alkali metal oxides (such as K2O and Na2O) and their corresponding alkali metal silicates (such as potassium silicate and sodium silicate) can destroy the crystal lattice structure or silicon-aluminum-oxygen network of high-melting-point metal oxides (such as CaO, Ca2SiO4, and calcium aluminate), promote the formation of a multi-component eutectic, and reduce the overall melting temperature, thereby achieving the effect of low-temperature eutectic.

[0047] The present application mixes biomass (agricultural and forestry waste) and household garbage in a certain proportion, homogenizes the mixture, and then crushes the homogenized material to less than 100 mesh through a crusher, and then enters a gas flow bed for gasification reaction. Or the homogenized material is formed into a fuel rod by a roll forming machine under pressure and enters a fluidized bed or a fixed bed for gasification reaction. Biomass plays a role of fluxing at this time, which can reduce the melting temperature of ash to a certain extent, and under the condition of ensuring the gasification efficiency and carbon conversion rate, the reaction temperature of the gasification furnace can be reduced, thereby reducing energy consumption. At the same time, the calorific value of biomass and household garbage is similar, so the gas yield and gas calorific value are also guaranteed in the case of doping biomass.

[0048] In Tables 2 to 6 of the embodiments of the present application, CaO / SiO2 is the mass ratio of CaO / SiO2 in the ash after gasification reaction. The mass fractions of CaO and SiO2 in the biomass ash and household garbage ash are determined according to the national standard "GB / T30725-2014 Solid Biomass Fuel Ash Composition Determination Method", and then the ash content (the mass of the ash after incineration accounts for the percentage of the mass of the corresponding household garbage / biomass) is measured according to the national standard "GB / T28731-2012 Solid Biomass Fuel Industrial Analysis Method". The relationship between the mass fractions of CaO and SiO2 in each biomass and household garbage, the ash content, and the mass ratio of CaO / SiO2 can be converted by the following formula.

[0049] In the process of household garbage gas flow bed high-temperature gasification reaction, according to the mixing ratio of 0% to 100% of the mass fraction of the waste crop fragments in Examples 1 to 5 and the fragments of household garbage, the fragments are fully mixed, the ash content is measured based on the national standard "GB / T28731-2012 Solid Biomass Fuel Industrial Analysis Method", and in the case of not adding biomass fluxing agent, the FT temperature of the household garbage ash is greater than 1500℃, the mass fractions of CaO and SiO2 in the household garbage ash are determined based on the national standard "GB / T30725-2014 Solid Biomass Fuel Ash Composition Determination Method", and the mass ratio of CaO / SiO2 is 2.7. In order to ensure that the FT temperature of the ash is reduced to below 1500℃, the mass ratio of CaO to SiO2 of the ash discharged from the gas flow bed should be less than 2.7 (0.5 to 1.8 in this embodiment), and in order to reduce the melting temperature of household garbage and make it smoothly discharge, it is necessary to add biomass with high SiO2 content to regulate its high-temperature melting characteristics. The mass ratio of CaO / SiO2 in the homogenized material is adjusted by calculation, and the ash contents of the biomass and household garbage are measured based on the national standard "GB / T28731-2012 Solid Biomass Fuel Industrial Analysis Method". ad1 , A ad2 The addition method of the biomass fluxing agent is calculated as follows:

[0050] wherein the mass fraction of biomass is M, the mass fraction of municipal solid waste is 1-M, the mass ratio of CaO / SiO2 is X, and X 1CaO , X 1SiO2 is the mass fraction of CaO and SiO2 in the biomass ash. 2CaO , X 2SiO2 is the mass fraction of CaO and SiO2 in the municipal solid waste ash.

[0051] It is found in Examples 1 to 5 that when the mass ratio of CaO / SiO2 in the ash X is between 0.5 and 1.8, it is helpful for the high-melting-point CaO (2570℃) and Ca2SiO4 (2130℃) to be converted into low-melting-point calcium silicate salts such as K2Ca6Si4O 15 (1200℃) and KAlSi3O8 (1150℃). Therefore, when the mass ratio of CaO / SiO2 X, the ash content A ad1 , A ad2 of the biomass and the municipal solid waste, the mass fraction X 1CaO , X 1SiO2 of CaO and SiO2 in the biomass ash, and the mass fraction X 2CaO , X 2SiO2 of CaO and SiO2 in the municipal solid waste ash are known, the mass fraction M of the biomass that needs to be added to make the mass ratio of CaO / SiO2 in the ash X can be calculated by the above formula.

[0052] It is found through experiments and calculations that when the composition of the municipal solid waste ash, the composition of the biomass ash, and the mass ratio of CaO / SiO2 are determined, the fluxing agent of the biomass fluxing agent can be determined, and the content of alkali metals in the biomass can also be determined.

[0053] Table 1 Ash composition determination results

[0054] The high-temperature viscosity curve of the municipal solid waste ash was determined by a high-temperature viscometer.

[0055] The household waste ash of the present embodiment is obtained from the ash residue after the household waste in a household waste incineration plant is fully subjected to gasification reaction. Without adding fluxing agent, the main existing form of calcium element in the ash composition of the household waste ash is determined by XRD (X-Ray Diffraction) to be CaO (melting point 2572°C) and Ca2SiO4 (melting point 2130°C). The ash residue is formed by the gasification reaction of the household waste at high temperature. Since the ash residue is a mixture of multiple components, there is a eutectic melting effect, and a calcium-silicon eutectic is mainly formed. The FT temperature of the eutectic is greater than 1500°C, and the temperature interval corresponding to the viscosity of 2.5-25 Pa·s is 1300-1340°C, with a temperature interval of 40°C, as shown in FIG. 1. The following embodiments are the change law of the flow temperature and viscosity-temperature characteristic curve of the ash residue in the case of adding fluxing agent. Figure 1

[0056] Example 1 The household waste and corn stalks are respectively crushed by a crusher and sieved to obtain crushed materials of the household waste and corn stalks with a particle size of less than 0.2 mm. Then the corn stalk crushed materials (heat value: 15.5 MJ / kg) are mixed with the crushed materials of the household waste at a mixing ratio of 30%, 40%, 50%, 60% and 70% by mass fraction, and then crushed and fully mixed again to obtain homogenized materials of the household waste and corn stalks with different mixing ratios. The homogenized materials with different mixing ratios are respectively formed into fuel rods by a roll forming machine under pressure and subjected to gasification reaction. The ash residue after the reaction is subjected to FT temperature and viscosity-temperature curve test, and part of the results are shown in Table 2. In the case of adding an appropriate amount of corn stalks, the main components of the ash residue change from CaO and Ca2SiO4 to K2Ca6Si4O 15 (1200°C) and KAlSi3O8 (1150°C). However, when the corn stalks are excessive, high-melting-point minerals MgAl2SiO8 (1890°C) and Ca7Mg(SiO4)4 (1554°C) appear in the main components of the ash residue, so the FT temperature of the ash residue shows a trend of first decreasing and then increasing. Since the heat value of the corn stalks is similar to that of the household waste, the FT temperature, the temperature point (T 2.5Pa∙s ) corresponding to the viscosity of 2.5 Pa·s, and the temperature point (T 25Pa∙s ​), temperature interval, the calorific value of the mixed material and cost, the best mixing ratio is 50% corn stalks, in which case the FT temperature is 1126.9°C, reaching a minimum, and the calorific value of the reactants decreases from 15.9 MJ / kg to 15.6 MJ / kg, a decrease of 1.9%; at this time, the flow temperature of the ash decreases by 373.1°C, which is within the temperature interval corresponding to a viscosity of 2.5-25 Pa·s, which is 986°C-1103°C, and the temperature interval becomes 117°C, as shown in the accompanying Figure 2 .

[0057] Table 2: Results of corn stalk mixing experiments

[0058] Compared to all household garbage, the FT temperature of the household ash after adding corn stalks decreases significantly, the calorific value does not change significantly, and the temperature interval widens significantly, which is conducive to reducing the temperature of the entrained flow bed reaction, increasing the adaptability of the ash outlet to temperature fluctuations, thereby reducing energy consumption and improving equipment stability.

[0059] Example 2 The household garbage and wheat straw were crushed and sieved by a crusher to obtain crushed materials of household garbage and wheat straw with a particle size of less than 0.2 mm. Then the crushed wheat straw (calorific value: 15.2 MJ / kg) was mixed with the crushed household garbage at mixing ratios of 30%, 40%, 50%, 60% and 70% by mass fraction, and the mixture was crushed again to obtain homogenized materials of household garbage and wheat straw at different mixing ratios. The homogenized materials at different mixing ratios were formed into fuel rods by a roll forming machine under pressure and subjected to gasification reaction. The FT temperature and viscosity-temperature curve of the ash after reaction were tested, and some results are shown in Table 3. With the addition of wheat straw, low-melting-point K2Ca6Si4O 15 , KAlSi3O8 gradually replaced CaO and Ca2SiO4 to become the main component of the gasification ash, so the FT temperature of the gasification ash continued to decrease and the temperature interval corresponding to a viscosity of 2.5-25 Pa·s widened with the addition of wheat straw. Since the calorific value of wheat straw is similar to that of household garbage, the mixing ratio, FT temperature, temperature point corresponding to a viscosity of 2.5 Pa·s (T 2.5Pa∙s ), and temperature point corresponding to a viscosity of 25 Pa·s (T 25Pa∙s, the temperature interval, the heat value of the mixed material, and the cost, etc. factors, the best mixing ratio is to add 40% of the wheat straw, the heat value of the reactant only decreases from 15.9 MJ / kg to 15.6 MJ / kg, which reduces by 1.9%; at this time, the flow temperature of the ash slag decreases by 396.4 ℃, the temperature interval corresponding to the viscosity of 2.5-25 Pa·s is 1171 ℃~1040 ℃, and the temperature interval becomes 131 ℃, as shown in the accompanying Figure 3 .

[0060] Table 3 Wheat straw mixing experiment results

[0061] Compared with the living garbage, the FT temperature of the living ash slag after adding the wheat straw decreases obviously, the heat value does not change obviously, and the temperature interval is widened obviously, which is beneficial to reduce the gas flow bed reaction temperature, increase the adaptability of the slag discharge port to the temperature fluctuation, thereby reducing the energy consumption and improving the equipment stability.

[0062] Example 3 The living garbage and the corn cob are respectively crushed by a crusher to obtain the crushed material of the living garbage and the crushed material of the corn cob with a particle size less than 0.2 mm, then the crushed material of the corn cob (heat value: 16.18 MJ / kg) is mixed with the crushed material of the living garbage again by crushing according to the mixing ratio of the mass fraction of 30%, 40%, 50%, 60%, and 70% to obtain the homogenized material of the living garbage and the corn cob with different mixing ratios, the homogenized material with different mixing ratios is respectively formed into a fuel rod by a roll forming machine under pressure and is subjected to a gasification reaction. The FT temperature of the ash slag after the reaction is tested, and part of the results are shown in Table 4. The change of the main mineral substances in the gasification ash slag of the corn cob and the corn straw is similar. The only difference is that the corn cob is rich in K element, K2O (melting point 770 ℃) is generated, and a low-temperature eutectic phenomenon is formed. Since the heat value of the corn cob is similar to that of the living garbage, the mixing ratio, the FT temperature, the temperature point (T 2.5Pa∙s ) corresponding to the viscosity of 2.5 Pa·s, the temperature point (T 25Pa∙s ) corresponding to the viscosity of 25 Pa·s, the temperature interval corresponding to the viscosity of 2.5-25 Pa·s, the heat value of the mixed material, and the cost, etc. factors are considered, the best mixing ratio is to add 50% of the corn cob, the heat value of the reactant increases from 15.9 MJ / kg to 16.0 MJ / kg, which increases by 0.6%; at this time, the flow temperature of the ash slag decreases by 425.1 ℃; the temperature interval corresponding to the viscosity of 2.5-25 Pa·s is 1174 ℃~953 ℃, and the temperature interval becomes 221 ℃, as shown in the accompanying Figure 4 .

[0063] Table 4 Corn cob blending experiment results

[0064] Compared with all living garbage, the FT temperature of living cinder after adding corn cob has a significant decrease, the calorific value increases slightly, and the temperature interval is obviously widened, which is conducive to reducing the gas flow bed reaction temperature, increasing the adaptability of the discharge port to temperature fluctuations, thereby reducing energy consumption and improving equipment stability. Compared with corn straw blending, the FT temperature of gasification cinder after corn cob blending has a more obvious decrease, and the improvement effect of viscosity temperature interval is more obvious.

[0065] Example 4 The corn straw / wheat straw mixture was obtained by mixing corn straw and wheat straw at a mass ratio of 1.5 (calorific value: 15.31 MJ / kg). The living garbage and the corn straw / wheat straw mixture were crushed and sieved by a crusher to obtain crushed materials of the living garbage and the corn straw / wheat straw mixture with a particle size of less than 0.2 mm. Then, the corn straw / wheat straw mixture crushed materials were again crushed and mixed with the crushed materials of the living garbage at blending ratios of 30%, 40%, 50%, 60%, and 70% by mass fraction to obtain homogenized materials of the living garbage and the corn straw / wheat straw mixture at different blending ratios. The homogenized materials at different blending ratios were formed into fuel rods by a roll forming machine under pressure and subjected to a gasification reaction. The FT temperature and viscosity-temperature curve of the cinder after the reaction were tested, and some results are shown in Table 5. As shown in Table 1, the ash composition of the blended biomass and corn straw is similar, so as the addition amount increases, the change of the main minerals in the blended gasification cinder is similar. Since the calorific value of the corn straw and wheat straw mixed biomass is similar to that of the living garbage, the best blending ratio is considered by taking into account the blending ratio, FT temperature, temperature point (T 2.5Pa∙s ) corresponding to 2.5 Pa·s viscosity, temperature point (T 25Pa∙s ) corresponding to 25 Pa·s viscosity, temperature interval corresponding to 2.5-25 Pa·s viscosity, calorific value of the mixed material, and cost, etc. When the addition amount is 50%, the calorific value of the reactant decreases from 15.9 MJ / kg to 15.6 MJ / kg, a decrease of 1.9%; at this time, the flow temperature of the cinder decreases by 407.5°C; the temperature interval corresponding to 2.5-25 Pa·s viscosity is 1004°C-1126°C, and the temperature interval is 122°C, as shown in FIG. 2. Figure 5

[0066] Table 5 Corn straw / wheat straw blending experiment results

[0067] ​Compared with all living garbage, the FT temperature of living ash after adding corn stalks / wheat stalks = 1.5 ratio has a significant decrease, the calorific value is almost unchanged, and the temperature interval is obviously widened, which is conducive to reducing the gas flow bed reaction temperature, increasing the adaptability of the discharge port to temperature fluctuations, thereby reducing energy consumption and improving equipment stability.

[0068] Example 5 The corn stalks / corn cob mixture was obtained by mixing corn stalks / corn cob = 1.5 (calorific value: 15.89 MJ / kg) in mass ratio. The living garbage and the corn stalks / corn cob mixture were crushed and sieved by a crusher to obtain crushed materials of the living garbage and the corn stalks / corn cob mixture with a particle size of less than 0.2 mm. Then the corn stalks / corn cob mixture crushed material was mixed with the crushed material of the living garbage again by crushing at a mixing ratio of 30%, 40%, 50%, 60% and 70% in mass fraction to obtain homogenized materials of the living garbage and the corn stalks / corn cob mixture at different mixing ratios. The homogenized materials at different mixing ratios were formed into fuel rods by a roll forming machine under pressure and subjected to gasification reaction. The ash after reaction was tested for FT temperature and viscosity-temperature curve, and part of the results are shown in Table 6. As shown in Table 6, the ash composition of the mixed biomass and corn stalks is similar, so as the addition amount increases, the change of the main minerals in the mixed gasification ash is similar. However, due to the rich K2O (melting point 770℃) in corn cob, the generation of KAlSi3O8 and the low temperature eutectic phenomenon are promoted. Therefore, compared with the mixed corn stalks and corn stalks / wheat stalks = 1.5, the fluxing effect of this mixed biomass is more obvious in improving the viscosity-temperature interval. Since the mixed corn stalks and corn cob have a similar calorific value to the living garbage, considering the mixing ratio, FT temperature, temperature point (T 2.5Pa∙s ) corresponding to 2.5 Pa·s viscosity, temperature point (T 25Pa∙s ) corresponding to 25 Pa·s viscosity, temperature interval corresponding to 2.5-25 Pa·s viscosity, calorific value of the mixed material and cost, etc., the best mixing ratio is 50% addition amount, and the reaction material calorific value remains unchanged; at this time, the flow temperature of the ash decreases by 379.9℃; the temperature interval corresponding to 2.5-25 Pa·s viscosity is 972℃~1091℃, and the temperature interval becomes 119℃, as shown in the accompanying drawings. Figure 6

[0069] Table 6 Experimental results of corn stalks / corn cob mixing

[0070] ​Compared with all living garbage, corn stalks, corn stalks / wheat straw = 1.5, the FT temperature of the living ash after adding corn stalks / corn cob = 1.5 ratio has a significant decrease, the heat value is basically unchanged, and the temperature interval is obviously widened, which is conducive to reducing the gas flow bed reaction temperature, increasing the adaptability of the discharge port to temperature fluctuations, thereby reducing energy consumption and improving equipment stability.

[0071] The gasification furnace discharge port is a certain distance from the center heating area of the gasification furnace, which causes the discharge port temperature to be lower than the actual reaction temperature of the gas flow bed, and has a certain volatility. When the temperature interval is wide, not only can the reaction temperature requirement be reduced, but also the temperature fluctuation of the discharge port can be met, increasing the stability of the equipment operation and realizing smooth liquid discharge.

[0072] The method for biomass-coordinated living garbage gasification furnace liquid discharge provided by the present application is proposed in view of the characteristics of high calcium and low silicon in living garbage ash. The biomass with high silicon and high alkali metal is co-gasified with the living garbage to achieve the purpose of reducing the melting temperature of the living garbage ash at a lower degree of loss of the gasification raw material heat value, significantly reducing the FT temperature of the living garbage ash for gasification reaction, thereby reducing the reaction temperature requirement, reducing the energy consumption of the equipment operation, and reducing the equipment operation cost. The gasification furnace is in the temperature interval corresponding to the viscosity of 2.5-25 Pa·s, the temperature interval is widened, the reaction temperature requirement is reduced, the temperature fluctuation of the discharge port can also be met, smooth liquid discharge is realized, and the stability of the equipment operation is increased. The specific advantages of the present application are as follows: 1. The present application is aimed at the characteristics of high calcium and low silicon in living garbage ash. The biomass with high silicon is selected to mix and gasify with the living garbage to regulate the ratio of acidic oxides and basic oxides, which can effectively reduce the melting temperature of the living garbage ash, improve the garbage ash viscosity-temperature characteristic curve, and reduce the living garbage ash flow temperature from more than 1500℃ to below 1200℃, so that the garbage ash viscosity-temperature characteristic curve meets the operation standard of high-temperature gasification technology.

[0073] 2. The present application uses agricultural and forestry waste as a fluxing agent for living garbage ash, realizes the resource utilization of agricultural and forestry waste, and reduces the operation cost.

[0074] 3. The present application proposes to mix multiple biomasses as fluxing agents in view of the influence of factors such as season and region on the types and yield of agricultural and forestry waste, realizes the adaptation to local conditions and the adaptation to the time, and reduces the storage cost of agricultural and forestry waste.

[0075] 4. The present application is aimed at the influence of factors such as season and region on the composition of living garbage ash, and starts from adjusting the composition ratio of living garbage ash. Different types of biomasses are mixed according to different ash compositions of different raw materials, which is high in flexibility and wide in applicability.

[0076] 5. The biomass fluxing agent prepared in the present application itself has a certain calorific value, compared with the addition of traditional fluxing agent, which will significantly reduce the calorific value of the reactants, the addition of biomass fluxing agent will not have a significant impact on the calorific value of the reactants, and even will improve the calorific value of the reactants.

[0077] The above description of disclosed embodiments enables one skilled in the art to make or use the application. Numerous modifications to these embodiments will be apparent to those skilled in the art, and the generic principles defined herein can be applied to other embodiments without departing from the spirit or scope of the application. Therefore, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for liquid ash discharge from a biomass co-processing municipal solid waste gasification furnace, characterized in that, Including the following steps: Composition determination: The ash composition of municipal solid waste ash and biomass ash were determined separately; Flux selection: Based on the ash composition of the municipal solid waste ash and biomass ash, select one type of biomass or a biomass mixture of at least two types of biomass as the biomass flux; Gasification reaction: municipal solid waste and biomass flux are mixed, and the resulting mixture is subjected to a gasification reaction to discharge ash and slag.

2. The method according to claim 1, characterized in that, In the component determination step, the ash component of the municipal solid waste ash mainly includes CaO, and the ash component of the biomass ash mainly includes SiO2. Based on the mass fraction of CaO in the ash component of the municipal solid waste ash, in the flux selection step, one type of biomass or a mixture of at least two types of biomass is selected as a biomass flux, and the mixing ratio of different biomass in the biomass mixture and the blending ratio of the biomass flux and the municipal solid waste in the gasification reaction step are adjusted so that the mass ratio of CaO to SiO2 in the ash is less than 2.

7.

3. The method according to claim 2, characterized in that, The mass ratio of CaO to SiO in the ash is 0.5 to 1.

8.

4. The method according to claim 1, characterized in that, The biomass is agricultural and forestry waste, which is at least one of corn stalks, wheat stalks, corn cobs, or rice husks.

5. The method according to claim 4, characterized in that, The biomass mass ratio in the biomass flux is corn straw: wheat straw: corn cob: rice husk = (0~7):(0~2):(0~2):(0~2).

6. The method according to claim 1, characterized in that, The biomass flux is selected from corn stalks, wheat stalks and corn cobs, and the mass ratio of corn stalks to wheat stalks in the biomass flux is 0.5 to 3.5 or the mass ratio of corn stalks to corn cobs is 0.5 to 3.

5.

7. The method according to claim 1, characterized in that, The gasification reaction step includes: Homogenization process: Municipal solid waste and biomass flux are crushed and screened separately to obtain fragments of municipal solid waste and biomass flux. The fragments of municipal solid waste and biomass flux are then crushed again at a certain mixing ratio and thoroughly mixed to obtain homogenized material.

8. The method according to claim 7, characterized in that, In the homogenization process, the municipal solid waste and the biomass flux are crushed and sieved respectively, and the particle size of the resulting fragments of the municipal solid waste and the biomass flux is less than 0.2 mm.

9. The method according to claim 7, characterized in that, The gasification reaction step also includes... Forming and processing: The homogenized material is sieved to form fuel chips or pressurized to form fuel rods, and then the fuel chips or fuel rods are fed into the gasifier for gasification reaction.

10. The method according to claim 9, characterized in that, The particle size of the fuel chips is less than 100 mesh.

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