Comprehensive utilization method of coal gasification fine slag

Abstract

The invention discloses a coal gasification fine slag comprehensive utilization method which comprises the following steps: mixing gasification fine slag slurry with a collecting agent, a foaming agent and an accelerant, and carrying out flotation to obtain a carbon-rich component and a carbon-poor component; reacting the first part of the carbon-rich component with hydrochloric acid to obtain a first solid phase in a reactant as a carbon material; obtaining a second solid phase in the second part of the carbon-rich component as a boiler fuel; and mixing the third solid phase with a dispersant and a modifier, and crushing the mixture to obtain the filler. According to the method, the coal gasification fine slag is utilized in a graded and quality-divided manner, so that a carbon material which can be used as a water treatment adsorbent, a boiler fuel which can replace part of fuel coal to serve as a blended combustion fuel and a filler which can play roles of filling, reinforcing and toughening materials and the like are respectively obtained, and the coal gasification fine slag is turned into wealth; and high value and comprehensive utilization of the gasified fine slag are realized.

Description

Technical Field

[0001] The invention relates to the technical field of industrial solid waste resource utilization, and in particular to a method for comprehensive utilization of coal gasification fine slag. Background Art

[0002] With the rapid development of my country's coal chemical industry, the emission of gasification ash is increasing day by day, and its large-scale disposal and resource utilization are imminent. Gasification ash is a solid residue formed by the physical and chemical transformation of inorganic minerals in coal and the residual carbon particles in coal during the incomplete combustion of coal and oxygen or oxygen-enriched air to produce CO and H2. Gasification ash includes coarse slag and fine slag. The coarse gasification slag is discharged from the slag discharge port at the bottom of the gasifier, and its composition is similar to boiler ash; the fine gasification slag is filtered from the ash water system during the washing and purification process of the raw coal gas of the gasifier.

[0003] At present, the mainstream coal gasification device is an entrained-flow coal gasification furnace, including water-coal slurry gasification and dry coal powder gasification. The coarse gasification slag produced by the two gasification devices is dehydrated to a water content of 15-20wt% by a vibrating screen after coming out of the slag scoop machine, and the fine gasification slag is dehydrated to a water content of 50-60wt% by a plate-and-frame filter press or a horizontal spiral centrifuge. The combustible content, water content, calorific value and annual output of the fine gasification slag produced by several typical large-scale entrained-flow coal gasification devices are shown in Table 1, and the ash composition of the fine gasification slag is shown in Table 2.

[0004] Table 1

[0005]

[0006]

[0007] From the data in Table 1, it can be seen that the gasified fine slag has the characteristics of high residual carbon content, high moisture content, and high ash content. Its ignition loss is relatively high (20-50wt%), which does not meet the requirements of cement admixtures. Its high residual carbon content hinders the gelling reaction between the gasified fine slag and cement or lime, and it cannot be directly used in products such as building materials.

[0008] Table 2

[0009] project <![CDATA[SiO2]]> <![CDATA[Fe2O3]]> <![CDATA[Al2O3]]> CaO MgO <![CDATA[SO3]]> <![CDATA[P2O5]]> <![CDATA[K2O]]> <![CDATA[Na2O]]> Xinjiang gasification fine slag 24.5％ 24.3％ 14.0％ 24.7％ 4.3％ 4.8％ 0.5％ 1.1％ 1.8％ Baotou gasification fine slag 44.0％ 8.3％ 21.5％ 14.3％ 1.4％ 3.3％ 0.0％ 0.4％ 6.8％ Ningdong gasification fine slag 53.8％ 9.9％ 18.2％ 9.1％ 2.6％ 1.6％ 0.3％ 2.5％ 2.0％

[0010] From the data in Table 2, it can be seen that the ash composition of gasification fine slag is mainly oxides of silicon, iron, aluminum, and calcium, accounting for 87-91%, with magnesium, sulfur, phosphorus, potassium, sodium and other elements. Silicon, iron, aluminum and calcium mainly exist in amorphous form, and some silicon elements exist in quartz phase. The carbon in gasification fine slag mainly includes amorphous carbon and graphite carbon. The amorphous carbon accounts for 90-95%, which is mainly organic carbon and has certain reactivity. The carbon particles in gasification fine slag are mainly divided into three types: dense amorphous, spherical and porous flocculent. Among them, the dense amorphous and porous flocculent forms are mainly composed of carbon components, while the spherical body is a eutectic formed by carbon and inorganic silicon, iron, calcium and aluminum components. The inorganic components in the carbon particles can be removed by chemical stripping.

[0011] A water-coal slurry gasification enterprise directly returned the concentrated gasification slag at the bottom of the clarifier to the coal slurry preparation system for recycling, which brought a series of problems: (1) It caused the coal slurry pipeline to wear more severely; (2) The number of micropores inside the gasification slag was significantly reduced compared with the raw coal, and some of the pore structures were blocked by the molten material. Its reaction activity was significantly lower than that of the raw coal, affecting the efficiency of the gasification system; (3) It caused some gasification ash to circulate in the system, causing wear and tear of the water system pipelines and equipment.

[0012] A dry coal pulverization gasification enterprise tried to feed gasification slag into a circulating fluidized bed boiler for co-firing, but encountered the following problems: (1) Since the water content of gasification slag reached about 60wt%, the boiler efficiency was low, the gasification slag feed had a strong corrosive effect on the boiler pipeline, the ash content in the flue gas increased, and the boiler wear was aggravated. The gasification slag could not be directly used for co-firing in a circulating fluidized bed boiler; (2) Combustion kinetics believes that coal char combustion is mainly determined by the diffusion of gas on the surface of coal char. Since the number of micropores in the gasification slag is reduced, the combustion performance of the gasification filter cake is lower than that of the raw coal; (3) Since the general design indicators of the boiler require ash content <25wt% and calorific value >18.0MJ / kg, and the ash content of the gasification slag is high (ash content 50-80wt%), the ratio of gasification slag to coal is limited to more than 20%.

[0013] Therefore, the current treatment method for gasification fine slag in my country is mainly landfill, which has led to serious land waste and environmental pollution. As the country's environmental protection requirements for the discharge of three wastes become more and more stringent, the reduction, resource utilization and harmless utilization of gasification fine slag are major problems faced by coal chemical companies. The resource utilization of gasification ash has become a technical problem that the coal chemical industry urgently needs to solve. Summary of the invention

[0014] In view of this, the main purpose of the present invention is to provide a method for comprehensive utilization of coal gasification fine slag, to utilize the coal gasification fine slag in a graded and quality-based manner, and to transform the coal gasification fine slag into treasure.

[0015] To achieve the above-mentioned object of the invention, the present invention provides a method for comprehensive utilization of coal gasification fine slag, comprising:

[0016] 1) Mixing the gasified fine slag slurry with a collector, a frother and a promoter, and flotation is performed to obtain carbon-rich components and carbon-poor components;

[0017] 2) reacting the carbon-rich component in the first part with hydrochloric acid to obtain a first solid phase in the reactant as a carbon material;

[0018] 3) obtaining the second solid phase in the carbon-rich component of the second part as boiler fuel;

[0019] 4) obtaining a third solid phase in the carbon-poor component, and mixing and crushing the third solid phase with a dispersant and a modifier to obtain a filler.

[0020] Furthermore, in step 1), the collector is selected from one or more of sodium oleate and sodium palmitate, the foaming agent is selected from one or more of polyethylene glycol PEG600, polyethylene glycol PEG800, polypropylene glycol PPG400, and polypropylene glycol PPG600, and the promoter is a PEO-PPO-PEO block copolymer.

[0021] Furthermore, the molecular weight of the PEO-PPO-PEO block copolymer is 4000-6000, wherein the PEO content is 35-45wt%.

[0022] Furthermore, the collector is added in an amount of 0.05-0.15% of the mass of the gasified fine slag slurry, the foaming agent is added in an amount of 0.01-0.03% of the mass of the gasified fine slag slurry, and the promoter is added in an amount of 0.001-0.005% of the mass of the gasified fine slag slurry.

[0023] Furthermore, in step 2), obtaining the first solid phase in the reactant includes: subjecting the reactant to solid-liquid separation to obtain the first solid phase, and drying the first solid phase.

[0024] Furthermore, the first solid phase is dried until the water content is reduced to <1 wt %, and a specific surface area of ​​300 to 600 m 2 / g of carbon material.

[0025] Furthermore, in step 3), obtaining the second solid phase in the second portion of carbon-rich components comprises: subjecting the second portion of carbon-rich components to solid-liquid separation to obtain the second solid phase, and drying the second solid phase.

[0026] Furthermore, the second solid phase is dried until the water content is reduced to 20-30 wt % and used as boiler fuel.

[0027] Furthermore, in step 4), obtaining the third solid phase in the carbon-depleted component comprises: subjecting the carbon-depleted component to solid-liquid separation to obtain the third solid phase, and drying the third solid phase.

[0028] Further, the third solid phase is dried until the water content is reduced to <1 wt %.

[0029] Furthermore, the dispersant is a polyester dispersant, and the added amount accounts for 0.2-2% of the mass of the third solid phase.

[0030] Furthermore, the modifier is selected from one or more of a self-milling coupling agent, a silane coupling agent, and a monoalkoxy titanate coupling agent, and the added amount accounts for 0.1 to 0.5% of the mass of the third solid phase.

[0031] Furthermore, in step 4), the pulverizing includes: pulverizing to obtain fine powder with D97<10μm and D50<2μm as filler.

[0032] Furthermore, the gasification fine slag slurry comes from the bottom of the clarification tank of the coal gasification water system.

[0033] Compared with the prior art, the present invention has the following advantages:

[0034] The present invention performs flotation on the gasification fine slag slurry to obtain a carbon-rich component and a carbon-poor component; reacts the carbon-rich component in the first part with hydrochloric acid to obtain a first solid phase in the reactant as a carbon material; obtains a second solid phase in the carbon-rich component in the second part as a boiler fuel; obtains a third solid phase in the carbon-poor component, and mixes and grinds the third solid phase with a dispersant and a modifier to obtain a filler. Therefore, the present invention performs graded and quality-based utilization of coal gasification fine slag, and obtains carbon materials that can be used as water treatment adsorbents, boiler fuels that can replace part of the fuel coal as a blended fuel, and fillers that can serve as filling, reinforcing, and toughening materials, etc., thereby turning waste into treasure for coal gasification fine slag, and achieving high value and comprehensive utilization of gasification fine slag.

[0035] Furthermore, the present invention adds a collector, a foaming agent and a promoter to mix with the gasified fine slag slurry during flotation, thereby improving the flotation effect of carbon particles in the gasified fine slag. The present invention adds a dispersant to the carbon-poor component, so that the dispersant and the carbon-poor component can be evenly mixed, and the addition of a modifier can make the crushed carbon-poor component and the modifier evenly mixed and fully contacted, thereby performing a modification treatment on the carbon-poor component.

[0036] Other features and advantages of the present invention will be described in detail through the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present invention but do not constitute a limitation of the present invention. In the accompanying drawings:

[0038] Figure 1 The figure is a schematic flow chart of a method for comprehensive utilization of coal gasification fine slag according to an example of the present invention. DETAILED DESCRIPTION

[0039] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0040] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0041] Furthermore, the terms “first”, “second”, etc. are used for descriptive purposes only and are not to be understood as indicating or implying relative importance.

[0042] Unless otherwise specified, the materials used in the embodiments of the present invention can be obtained from commercial channels.

[0043] The present invention provides a method for comprehensive utilization of coal gasification fine slag, comprising:

[0044] 1) Mixing the gasified fine slag slurry with a collector, a frother and a promoter, and flotation is performed to obtain carbon-rich components and carbon-poor components;

[0045] 2) reacting the carbon-rich component in the first part with hydrochloric acid to obtain a first solid phase in the reactant as a carbon material;

[0046] 3) obtaining the second solid phase in the carbon-rich component of the second part as boiler fuel;

[0047] 4) obtaining a third solid phase in the carbon-poor component, and mixing and crushing the third solid phase with a dispersant and a modifier to obtain a filler.

[0048] Furthermore, in step 1), the collector is selected from one or more of sodium oleate and sodium palmitate, the foaming agent is selected from one or more of polyethylene glycol PEG600, polyethylene glycol PEG800, polypropylene glycol PPG400, and polypropylene glycol PPG600, and the promoter is a PEO-PPO-PEO block copolymer with a molecular weight of 4000 to 6000, wherein the PEO content is 35 to 45 wt%.

[0049] Gasification fine slag is mainly composed of loose, porous, irregularly shaped carbon particles and molten ash particles formed under high temperature conditions. The carbon particles present a layered porous structure and a flocculent structure, and have a certain degree of hydrophobicity; the ash particles have a strong hydrophilicity.

[0050] The main function of the collector selected in the present invention is to improve the hydrophobicity of the surface of the carbon particles. The gasified fine slag mixed liquid is a weak alkaline environment. Sodium oleate, sodium palmitate, etc. as collectors have hydrophilic acid radical ions at one end and hydrophobic hydrocarbon chains at the other end under alkaline conditions. The acid radical ions are combined with ash in the form of chemical adsorption and are difficult to adhere to the bubbles and be taken out. The hydrophobic hydrocarbon chains are combined with the carbon particles to make the carbon particles hydrophobic and float up with the bubbles during the flotation process.

[0051] The function of introducing a frother in the flotation process of the present invention is to capture hydrophobic carbon particles and bring them into the gas phase while leaving hydrophilic ash particles. Polyethylene glycol (PEG600 / PEG800) and polypropylene glycol (PPG400 / PPG600) can obtain better flotation effect (high flotation speed, yield and selectivity) due to their better surface activity. The speed of flotation of ultrafine particles using a mixture of a promoter and polyol is 3 to 4 times that of using a promoter or polyol alone.

[0052] The promoter selected by the present invention as a surface adjuster can improve the hydrophobicity of carbon particles, and the adsorption of the promoter on the air-water interface can form better bubbles and a stable foam layer. PEO-PPO-PEO block copolymers are non-ionic macromolecular surfactants. Compared with small molecular weight hydrocarbon surfactants, PEO-PPO-PEO block copolymers have unique properties. The surface activity of block copolymers is also different from that of small molecular weight hydrocarbon surfactants. Block copolymers have higher surface activity, and lower concentrations can greatly reduce the surface tension of the solution; block copolymers form molecular brush structures at the air-liquid interface, showing surface activity different from that of small molecular weight hydrocarbon surfactants. In the change of the surface tension of the block copolymer solution with concentration, the appearance of the turning point in the molecular brush region indicates that the interaction between the block copolymer molecules begins to strongly affect the surface tension of the solution.

[0053] PEO-PPO-PEO block copolymers can be used to adjust the surface properties of carbon particles, thereby improving the flotation effect of carbon particles. It has a dual effect on flotation, which can change the surface properties of carbon particles and enhance the emulsification effect of collectors. For easy-to-select coal, only a small amount of collector is usually required, so compared with the emulsification effect, the block copolymer mainly plays a surface adjustment role. For medium-selectable and difficult-to-select coal, flotation requires a larger amount of collector, so the surface adjustment and emulsification of the polymer are very important. The carbon particles of gasified fine slag belong to difficult-to-select coal. Based on the study of surface tension and contact angle, it was found that for the copolymer on the coal-water interface, the PPO group is adsorbed to the hydrophobic site (carbon particles) through hydrophobic action, while the PEO group is adsorbed to the hydrophilic site (ash) through hydrogen bonding. The coverage of the surface hydrophilic groups by the block copolymer promoter is believed to be the reason for the increase in the hydrophobicity of the coal surface, thereby improving the flotation effect of carbon particles.

[0054] Preferably, the collector is added in an amount of 0.05-0.15% of the mass of the gasified fine slag slurry, the foaming agent is added in an amount of 0.01-0.03% of the mass of the gasified fine slag slurry, and the promoter is added in an amount of 0.001-0.005% of the mass of the gasified fine slag slurry.

[0055] In some embodiments, in step 2), the concentration of the hydrochloric acid solution is 3-10 wt %.

[0056] In some embodiments, in step 2), obtaining the first solid phase in the reactant includes: subjecting the reactant to solid-liquid separation to obtain a first solid phase containing 50-60% water, and drying the first solid phase.

[0057] Preferably, the first solid phase is dried until the water content is reduced to <1 wt %, and a specific surface area of ​​300 to 600 m 2 / g of carbon material.

[0058] In some embodiments, in step 3), obtaining the second solid phase in the second portion of carbon-rich components includes: subjecting the second portion of carbon-rich components to solid-liquid separation to obtain a second solid phase containing 50-60% water, and drying the second solid phase.

[0059] Preferably, the second solid phase is dried until the water content is reduced to 20-30 wt % and used as boiler fuel.

[0060] In some embodiments, in step 4), obtaining the third solid phase of the carbon-depleted component comprises: subjecting the carbon-depleted component to solid-liquid separation to obtain a third solid phase containing 50-60% water, and drying the third solid phase.

[0061] Preferably, the third solid phase is dried until the water content is reduced to <1 wt%.

[0062] In some embodiments, the dispersant is a polyester dispersant, and preferably, the added amount accounts for 0.1-0.5% of the mass of the third solid phase.

[0063] In some embodiments, the modifier is selected from one or more of a self-milling coupling agent, a silane coupling agent, and a monoalkoxy titanate coupling agent. Preferably, the added amount accounts for 0.1-1% of the mass of the third solid phase.

[0064] In some embodiments, in step 4), the dried third solid phase is conveyed via a screw feeder, a dispersant is added at the feed point of the screw conveyor, and then enters a grinder for ultrafine grinding, a modifier is added to the grinder, and fine powder with D97<10μm and D50<2μm is obtained by grinding as a filler for rubber plastic.

[0065] As described above, the present invention adds a dispersant at the feed point of the screw conveyor, so that the dispersant and the carbon-poor component can be evenly mixed. The screw conveyor serves as both a conveying device and a mixing and stirring device. Adding a modifier to the pulverizer allows the ultrafinely crushed carbon-poor component to be evenly mixed and fully contacted with the modifier, and the carbon-poor component is modified. Therefore, the addition of the dispersant and the modifier are respectively integrated in the process of conveying and ultrafine crushing, which saves equipment and improves the mixing and modification effects.

[0066] In the present invention, the gasification fine slag slurry comes from the bottom of the clarification tank of the coal gasification water system.

[0067] The present invention does not limit the order of step 2), step 3) and step 4).

[0068] Conventional equipment in the field can be used in the present invention, for example: the filtering equipment can be a vacuum plate and frame filter or a horizontal spiral centrifuge, the drying equipment can be a paddle dryer or a disc dryer, and the pulverizer can be a three-ring medium-speed micro powder mill or a steam mill.

[0069] The present invention is further described below with detailed exemplary embodiments, but these embodiments do not constitute any limitation to the present invention.

[0070] Example 1

[0071] refer to Figure 1 The method for comprehensive utilization of coal gasification fine slag according to the embodiment of the present invention comprises:

[0072] (1) The concentrated gasified slag from the bottom of the clarification tank of the coal gasification water system is directly fed into the flotation device. The combustible content and ash composition of the gasified slag are shown in Tables 1 and 2 above for the parameters of Xinjiang gasified slag. The gasified slag slurry flow rate is 62 t / h, and the solid content is 10%. Sodium oleate (Shandong Longhui Chemical Co., Ltd.) is added as a collector in the flotation device in an amount of 0.07% of the mass of the gasified slag slurry. Polyethylene glycol PEG600 (Jiangsu Hai'an Petrochemical Plant) is added as a foaming agent in an amount of 0.015% of the mass of the gasification fine slag slurry, and then add a promoter (PEO-PPO-PEO block copolymer), the addition amount is 0.002% of the mass of the gasification fine slag slurry, the molecular weight of the PEO-PPO-PEO block copolymer is 4200 (Shanghai Yanke New Materials Co., Ltd.), the PEO content is 40%, and water circulation is used for flotation to obtain carbon-rich components and carbon-poor components respectively. The carbon content in the carbon-rich component is 75%, the carbon recovery rate is 70%, and the carbon-poor component contains 21.9% carbon.

[0073] (2) One third of the carbon-rich components obtained by flotation enter the reactor, and hydrochloric acid solution is added for stirring reaction. The concentration of the hydrochloric acid solution is 5wt%. The amount of hydrochloric acid added is calculated according to the measured contents of Fe2O3, Al2O3, CaO, MgO, K2O, and Na2O in the gasification fine slag ash. The metal oxides such as Fe2O3, Al2O3, CaO, MgO, K2O, and Na2O in the carbon-rich components react with hydrochloric acid to generate soluble substances that dissolve in the water phase. About 70% of the weight of the carbon-rich components is reacted into the solution. The reaction product enters the filtering equipment (horizontal spiral centrifuge) for filtration to obtain a solid phase containing 60% water. The filtrate is dehydrated and separated from the salt and then enters the ash water tank of the gasification water system for recycling. The solid phase components obtained by filtration enter the drying equipment (paddle dryer) for two-stage drying to reduce the water content of the solid phase to <1wt%, and obtain a specific surface area of ​​580m 2 / g of carbon material 0.69t / h, can be used as water treatment adsorbent, annual by-product carbon material ~5500t.

[0074] (3) Two-thirds of the carbon-rich components obtained by flotation enter the filtering equipment (horizontal spiral centrifuge) for filtration to obtain a solid phase containing ~60% water. The filtrate enters the ash water tank of the gasification water system for recycling. The solid phase components obtained by filtration enter the drying equipment (paddle dryer) for drying, reducing the solid phase water content to about 25wt% of fuel carbon 2.23t / h, with a calorific value of 20.65MJ / kg (received basis), which can be used as boiler fuel for blending, saving ~18,000 tons of fuel coal annually.

[0075] (4) The carbon-poor component obtained by flotation enters the filtering equipment (horizontal spiral centrifuge) for filtration to obtain a solid phase containing ~60% water. The filtrate enters the ash water tank of the gasification water system for recycling. The solid phase component obtained by filtration enters the drying equipment (paddle dryer) for two-stage drying to reduce the water content of the solid phase to ~1wt%. The dried material is conveyed by a screw feeder, and a dispersant (polyester dispersant SP-24000, Shanghai Zhehua Company) is added at the feed point of the screw conveyor. The dispersant addition amount is 0.15% of the material mass. Then it enters the pulverizer (steam mill) for ultrafine grinding. A modifier (grinding coupling agent L-3G, Chongqing Jiashitai Chemical Co., Ltd.) is added to the pulverizer. The modifier addition amount is 0.2% of the material mass. After grinding, D97<10μm is obtained, of which particles <2μm account for >50%. Ultrafine powder particles 3.7t / h, with a volume average diameter of 0.6μm, can be used as fillers for rubber and plastics, and 30,000 tons of fillers are produced as by-products annually. The output of the above-mentioned coal gasification fine slag comprehensive utilization products is shown in Table 3.

[0076] Table 3

[0077]

[0078] Example 2

[0079] (1) The concentrated gasified slag from the bottom of the clarification tank of the coal gasification water system is directly fed into the flotation device. The combustible content and ash composition of the gasified slag are shown in Tables 1 and 2 above for the parameters of the Ningdong gasified slag. The flow rate of the gasified slag slurry is 145.1 t / h, and the solid content is 10%. Sodium oleate (Shandong Longhui Chemical Co., Ltd.) is added as a collector in an amount of 0.1% of the mass of the gasified slag slurry. Polyethylene glycol PEG600 (Jiangsu Hai'an Petrochemical Plant) is added as a foaming agent. The amount is 0.02% of the mass of the gasification fine slag slurry, and then a promoter (PEO-PPO-PEO block copolymer) is added in an amount of 0.003% of the mass of the gasification fine slag slurry, the molecular weight of the PEO-PPO-PEO block copolymer is 4200 (Shanghai Yanke New Materials Co., Ltd.), the PEO content is 40%, and water circulation is used for flotation to obtain carbon-rich components and carbon-poor components respectively. The carbon content in the carbon-rich component is 73%, the carbon recovery rate is 60%, and the carbon content in the carbon-poor component is 10.2%.

[0080] (2) 40% of the carbon-rich components obtained by flotation enter the reactor, and hydrochloric acid solution is added for stirring reaction. The concentration of the hydrochloric acid solution is 5wt%, and about 44% of the weight of the carbon-rich components is reacted into the solution. The reaction product enters the filtering equipment (horizontal spiral centrifuge) for filtration to obtain a solid phase containing 60% water. The filtrate is dehydrated and salted before entering the gray water tank of the gasification water system for recycling. The solid phase components obtained by filtration enter the drying equipment (paddle dryer) for two-stage drying to reduce the water content of the solid phase to <1wt%, and obtain a specific surface area of ​​350m2 / g of carbon material 0.73t / h, can be used as water treatment adsorbent, annual by-product carbon material ~5900t.

[0081] (3) 60% of the carbon-rich components obtained by flotation enter the filtering equipment (horizontal spiral centrifuge) for filtration to obtain a solid phase containing 60% water. The filtrate enters the ash water tank of the gasification water system for recycling. The solid phase components obtained by filtration enter the drying equipment (paddle dryer) for drying, reducing the solid phase water content to about 25wt% of fuel carbon 2.0t / h, with a calorific value of 21.50MJ / kg (received basis), which can be used as boiler fuel for blending, saving 16,000 tons of fuel coal annually.

[0082] (4) The carbon-poor component obtained by flotation enters the filtering equipment (horizontal spiral centrifuge) for filtration to obtain a solid phase with a water content of ~60%. The filtrate enters the ash water tank of the gasification water system for recycling. The solid phase component obtained by filtration enters the drying equipment (paddle dryer) for two-stage drying to reduce the water content of the solid phase to ~1wt%. The dried material is conveyed by a screw feeder, and a dispersant (polyester dispersant SP-24000, Shanghai Zhehua Company) is added at the feed point of the screw conveyor. The dispersant addition amount is 0.3% of the material mass. Then it enters the pulverizer (steam mill) for ultrafine grinding. A modifier (grinding coupling agent L-3G, Chongqing Jiashitai Chemical Co., Ltd.) is added to the pulverizer. The modifier addition amount is 0.4% of the material mass. After grinding, D97<10μm is obtained, of which particles <2μm account for >50%. Ultrafine powder particles 12.0t / h, with a volume average diameter of 0.55μm, can be used as fillers for rubber and plastics, and 96,000 tons of fillers are produced as by-products annually. The output of the above-mentioned coal gasification fine slag comprehensive utilization products is shown in Table 4.

[0083] Table 4

[0084]

[0085] Example 3

[0086] The difference from Example 1 is that in step 4), the amount of polyester dispersant added is 0.3% of the material mass, and the amount of modifier (grinding aid coupling agent L-3G, Chongqing Jiashitai Chemical Co., Ltd.) added is 1% of the material mass. After crushing, ultrafine powder particles with D97<10μm are obtained, of which particles <2μm account for >50%, with a volume average diameter of 0.5μm, which can be used as fillers for rubber and plastics, and an annual by-product of 30,000 tons of fillers is obtained.

[0087] Example 4

[0088] The difference from Example 1 is that the addition amount of the collector sodium oleate is 0.05% of the mass of the gasified fine slag slurry, the addition amount of the foaming agent PEG600 is 0.01% of the mass of the gasified fine slag slurry, and the addition amount of the promoter PEO-PPO-PEO block copolymer is 0.001% of the mass of the gasified fine slag slurry.

[0089] The obtained carbon-rich component contains 65% carbon, with a carbon recovery rate of 58%, and the carbon-poor component contains 29.7% carbon.

[0090] Example 5

[0091] The difference from Example 1 is that the addition amount of the collector sodium oleate is 0.15% of the mass of the gasified fine slag slurry, the addition amount of the foaming agent PEG600 is 0.03% of the mass of the gasified fine slag slurry, and the addition amount of the promoter PEO-PPO-PEO block copolymer is 0.005% of the mass of the gasified fine slag slurry.

[0092] The obtained carbon-rich component contains 77% carbon, with a carbon recovery rate of 73%, and the carbon-poor component contains 19.9% ​​carbon.

[0093] Comparative Example 1

[0094] The difference from Example 1 is that no promoter PEO-PPO-PEO block copolymer is added.

[0095] The obtained carbon-rich component has a carbon content of 73.5%, a carbon recovery rate of 68%, and a carbon-poor component has a carbon content of 23.2%. Compared with Example 1, Comparative Example 1 does not add a promoter. Under the same other conditions, the obtained carbon-rich component has a lower carbon content and a lower recovery rate, and the carbon-poor component has a higher carbon content.

[0096] Comparative Example 2

[0097] The difference from Example 1 is that no promoter is added, and the added collector and frother are conventional flotation additives, that is, the collector is light diesel oil, the addition amount is 0.07%, and the frother is octanol, the addition amount is 0.015%.

[0098] The obtained carbon-rich component has a carbon content of 60%, a carbon recovery rate of 55%, and a carbon-poor component has a carbon content of 32.4%. Comparative Example 2 Compared with Example 1, the collector and the foaming agent are both conventional additives, and the addition amount is the same as that in Example 1. The obtained carbon-rich component has a lower carbon content and a lower recovery rate, and the carbon content of the carbon-poor component is significantly increased.

[0099] In summary, the method for comprehensive utilization of coal gasification fine slag according to the embodiment of the present invention has the following beneficial effects:

[0100] The present invention can be used to produce a specific surface area of ​​300 to 600 m 2 / g of carbon material can be used as water treatment adsorbent in chemical plants to achieve high-value resource utilization of gasification fine slag.

[0101] Since the design index of power boilers of coal chemical enterprises generally requires ash content <25% and calorific value >18.2MJ / kg, and the ash content of gasified fine slag is high (ash content 50-80%), the ratio of gasified fine slag to coal blending is limited to more than 20%. In view of the high residual carbon content of gasified fine slag, the carbon-rich gasified fine slag recovered by the present invention has a carbon content of more than 70%, which can be used as a blended fuel for coal-fired boilers, can replace part of the fuel coal, save fuel costs, and realize the cascade comprehensive utilization of gasified fine slag.

[0102] The ultrafine gasified fine slag filler prepared by the present invention is added to polymer materials such as PE, PP, PVC, epoxy resin, ethylene propylene rubber, etc., to play the role of filling, reinforcing and toughening the material performance, thereby realizing the high-value utilization of the gasified fine slag.

[0103] Obviously, the above embodiments of the present invention are merely examples for clearly explaining the present invention, and are not intended to limit the implementation methods of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is impossible to list all implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are within the spirit scope of the present invention.

Claims

1. A method for comprehensive utilization of coal gasification fine slag, characterized in that: include: 1) Mixing the gasified fine slag slurry with a collector, a frother and a promoter, and flotation is performed to obtain carbon-rich components and carbon-poor components; 2) reacting the carbon-rich component in the first part with hydrochloric acid to obtain a first solid phase in the reactant as a carbon material; 3) obtaining the second solid phase in the carbon-rich component of the second part as boiler fuel; 4) obtaining a third solid phase in the carbon-poor component, and mixing and crushing the third solid phase with a dispersant and a modifier to obtain a filler.

2. The method for comprehensive utilization of coal gasification fine slag according to claim 1, characterized in that: In step 1), the collector is selected from one or more of sodium oleate and sodium palmitate; and / or the foaming agent is selected from one or more of polyethylene glycol PEG600, polyethylene glycol PEG800, polypropylene glycol PPG400, and polypropylene glycol PPG600; and / or the promoter is a PEO-PPO-PEO block copolymer.

3. The method for comprehensive utilization of coal gasification fine slag according to claim 2, characterized in that: The added amount of the collector is 0.05-0.15% of the mass of the gasified fine slag slurry, the added amount of the foaming agent is 0.01-0.03% of the mass of the gasified fine slag slurry, and the added amount of the promoter is 0.001-0.005% of the mass of the gasified fine slag slurry.

4. The method for comprehensive utilization of coal gasification fine slag according to any one of claims 1 to 3, characterized in that: In step 2), obtaining the first solid phase in the reactant comprises: subjecting the reactant to solid-liquid separation to obtain the first solid phase, and drying the first solid phase; Furthermore, the first solid phase is dried until the water content is reduced to <1 wt %.

5. The method for comprehensive utilization of coal gasification fine slag according to any one of claims 1 to 4, characterized in that: In step 3), obtaining the second solid phase in the second portion of carbon-rich components comprises: subjecting the second portion of carbon-rich components to solid-liquid separation to obtain the second solid phase, and drying the second solid phase; Furthermore, the second solid phase is dried until the water content is reduced to 20-30 wt%.

6. The method for comprehensive utilization of coal gasification fine slag according to any one of claims 1 to 5, characterized in that: In step 4), obtaining the third solid phase in the carbon-depleted component comprises: subjecting the carbon-depleted component to solid-liquid separation to obtain the third solid phase, and drying the third solid phase; Further, the third solid phase is dried until the water content is reduced to <1 wt %.

7. The method for comprehensive utilization of coal gasification fine slag according to any one of claims 1 to 6, characterized in that: The dispersant is a polyester dispersant. Preferably, the amount of the dispersant added accounts for 0.1-0.5% of the mass of the third solid phase.

8. The method for comprehensive utilization of coal gasification fine slag according to any one of claims 1 to 7, characterized in that: The modifier is selected from one or more of a self-milling coupling agent, a silane coupling agent, and a monoalkoxy titanate coupling agent. Preferably, the amount of the modifier added accounts for 0.1-1% of the mass of the third solid phase.

9. The method for comprehensive utilization of coal gasification fine slag according to any one of claims 1 to 8, characterized in that: In step 4), the pulverizing includes: pulverizing to obtain fine powder with D97<10μm and D50<2μm as filler.

10. The method for comprehensive utilization of coal gasification fine slag according to any one of claims 1 to 9, characterized in that: The gasification fine slag slurry comes from the bottom of the clarification tank of the coal gasification water system.

Images