阅读说明：本技术 水泥厂协同处理含有机质危废制备混合燃料的方法 (Method for preparing mixed fuel by cooperatively treating hazardous wastes containing organic matters in cement plant ) 是由 尹小林 余智英 宋剑飞 于 2020-07-22 设计创作，主要内容包括：水泥厂协同处理含有机质危废制备混合燃料的方法,包括如下步骤：(1)改性处理；(2)制混合燃料粉；(3)喷入窑炉燃烧。本发明工艺简单、投资少,既对危废的材料成分改性处理,且消除挥发性异味,并稳定重金属等污染物,利用煤粉的天然吸附性能消除干燥粉磨过程中产生的异味等污染物,处理过程中无二次污染；将含有机质危废改性处理作为水泥厂燃煤的燃烧促进组分(即助燃剂)和替代燃料,混合粉磨制成混合燃料粉,利于含有机质危险废弃物的清洁燃烧、和入窑煤粉的清洁燃烧,可有效节省燃煤,利于环保,利于绿色、低碳、循环经济的持续发展。(The method for preparing the mixed fuel by cooperatively treating hazardous wastes containing organic substances in the cement plant comprises the following steps: (1) modification treatment; (2) preparing mixed fuel powder; (3) spraying into a kiln for combustion. The invention has simple process and less investment, not only modifies the material components of the hazardous wastes, but also eliminates volatile peculiar smell, stabilizes pollutants such as heavy metal and the like, eliminates the pollutants such as peculiar smell and the like generated in the drying and grinding process by utilizing the natural adsorption performance of the coal powder, and has no secondary pollution in the processing process; the modification treatment of hazardous waste containing organic substances is used as a combustion promoting component (namely a combustion improver) and a substitute fuel of fire coal of a cement plant, and the mixed fuel powder is prepared by mixing and grinding, so that the clean combustion of hazardous waste containing organic substances and the clean combustion of pulverized coal entering a kiln are facilitated, the fire coal can be effectively saved, the environmental protection is facilitated, and the sustainable development of green, low-carbon and circular economy is facilitated.)

1. A method for preparing mixed fuel by cooperatively processing hazardous wastes containing organic substances in a cement plant is characterized by comprising the following steps: the method comprises the following steps:

(1) modification treatment: adding an oxidation promoter and a heavy metal ion stabilizer into the pre-treatment process of crushing, stirring and mixing or rolling and mixing hazardous wastes containing organic matters for modification treatment, and carrying out mixed reaction for 3-90 min to obtain a modified combustion-supporting material;

(2) preparing mixed fuel powder: continuously adding the modified combustion-supporting material obtained in the step (1) from the coarse powder return material of the coal mill or continuously adding the modified combustion-supporting material from an inlet pipeline of the coal mill, and grinding the mixture into mixed fuel powder with 80um screen residue less than 3 percent and water content less than 1.5 percent;

(3) spraying into a kiln for combustion: and (3) sending the mixed fuel powder obtained in the step (2) into a cement kiln system to serve as head coal and/or tail coal fuel, and spraying the mixture into a kiln/furnace by a coal injection pipe to burn and fire clinker.

2. The method for preparing the mixed fuel by the synergistic treatment of the hazardous organic waste in the cement plant according to claim 1, wherein in the step (1), the hazardous organic waste is one or a mixture of more than two of agroforestry, fishery and animal medicine hazardous waste, organic solvent-containing waste, mineral oil-containing waste, oil-water waste, hydrocarbon/water mixture waste, emulsion waste, polychlorinated (bromo) biphenyl waste, distillation residue, dye waste, coating waste, organic cyanide waste, phenol-containing waste and ether-containing waste, which can enter a coal mill and has a heat value of 600-8000 x4.18KJ/Kg.

3. The method for preparing the mixed fuel by the synergistic treatment of the hazardous wastes containing organic matters in the cement plant according to the claim 1 or 2, characterized in that in the step (2), the addition amount of the modified combustion-supporting material is 1-80%, preferably 10-50%, more preferably 10-30% of the mass of the raw coal.

4. The method for producing blended fuel by using cement plant to co-process hazardous waste containing organic substances according to any one of claims 1 to 3, wherein in the step (1), the oxidation accelerator is at least one of ferrate, permanganate, percarbonate, fluorosulfonic acid, benzoic acid and its salts, naphthenic acid and its salts, and nitrate.

5. The method for preparing the mixed fuel by the synergistic treatment of the hazardous waste containing the organic substances in the cement plant according to the claim 1 or 2, wherein the amount of the oxidation accelerator used in the step (1) is 0.2-6%, preferably 1-5% of the amount of the hazardous waste containing the organic substances.

6. The method for preparing a mixed fuel by using a cement plant to cooperatively process hazardous wastes containing organic matters according to any one of claims 1 to 5, wherein in the step (1), the heavy metal ion stabilizer is at least one of sodium/potassium silicate, sodium/potassium metaaluminate, polyvinyl alcohol, sodium/potassium thiosulfate and phytic acid.

7. The method for preparing the mixed fuel by the synergistic treatment of the hazardous wastes containing the organic substances in the cement plant according to one of the claims 1 to 6, wherein in the step (1), the amount of the heavy metal ion stabilizer is 0.3 to 8 percent of the mass of the hazardous wastes containing the organic substances.

8. The method for preparing a blended fuel by using hazardous wastes containing organic substances in cooperation with a cement plant according to any one of claims 1 to 7, wherein in the step (1), one or a mixture of two or more of lime, carbide slag, cement powder, slag powder, silica fume powder, calcium carbonate powder, bauxite, bentonite, zeolite powder, attapulgite powder and other carbon-containing organic compound materials is/are added as auxiliary materials in the modification treatment process.

Technical Field

The invention relates to a recycling method of hazardous waste containing organic substances, in particular to a method for preparing mixed fuel by cooperatively processing hazardous waste containing organic substances in a cement plant.

Background

The hazardous waste in China has the characteristics of large production amount, multiple types and wide sources, the hazardous waste is divided into 46 types in the national hazardous waste list (2016 edition), and the total number of the hazardous waste is 479 types, wherein the proportion of the carbon-containing organic matter hazardous waste is not less. In recent 20 years, three major treatment technologies, mainly incineration treatment technology, curing stabilization technology and cement kiln co-treatment, have been developed in China. At present, the cement kiln is used for disposing hazardous wastes together, which is one of the most important and effective technical approaches.

In the last decade, the policy documents issued by the ministry of China in succession locate the cement kiln to co-dispose waste at the strategic height of promoting environmental protection, developing circular economy, promoting energy conservation and emission reduction, and adjusting industrial structure. The progress of the waste co-treatment of the cement kiln in China is effectively promoted, and nearly two hundred cement enterprises which co-treat dangerous waste or pass the environmental evaluation or are in the environmental evaluation stage are developed. However, compared with the developed countries abroad, in the aspect of preparing the alternative fuel, the cement enterprises in China are influenced by the investment and cost bearing capacity due to the huge difference of the national conditions and the exchange rate converted cement price, and the waste alternative fuel has the practical problems of insufficient stable components, nonuniform shape, low heat value and the like, so that the alternative fuel product is insufficiently combusted in the cement kiln, and the energy consumption of the system is increased. In the aspect of replacing fuel, the average replacement rate of the fuel is far lower than that of developed countries in China in the cement production process by more than 30%, the maximum replacement rate is more than 90%, the replacement rate of fuel wastes of most cement enterprises in China is 0%, and the replacement rate of the most advanced typical enterprise fuel wastes is less than 10%.

Although cement kiln systems and clinker minerals have great compatibility, wastes easily cause adverse effects on the working condition stability of the kiln systems, pollutant discharge and cement clinker performance, technical workers at home and abroad carry out a great deal of research and practice for solving or reducing the effects of various wastes including hazardous wastes on the cement kiln systems in the cooperative treatment of the cement kiln systems, and the conventional cooperative treatment method can be roughly divided into the following steps:

(1) the method for burning kiln head sprayed into rotary kiln mainly includes three modes:

(A) after the hazardous waste liquid (water-containing waste liquid, waste solvent, waste oil and the like) is subjected to blending, filtering and pretreatment, the hazardous waste liquid is pumped to a kiln hood and sprayed into a rotary kiln for incineration. The method is suitable for the cooperative treatment of the hazardous waste liquid with high calorific value, low chlor-alkali and low moisture, is equivalent to oil injection combustion, can save a large amount of fuel, but the hazardous waste liquid with high water content or containing chlor-alkali elements can influence the burning of the first coal or generate a large amount of chloric acid aerial fog and the like to influence the kiln conditions, not only can not effectively utilize organic energy sources in the hazardous waste liquid, but also can increase energy consumption.

(B) The powdery hazardous waste is conveyed to a kiln head cover through pipeline compressed air and is sprayed into the rotary kiln for incineration. The method has the advantages that firstly, the method influences the burning of the head coal and increases the heat consumption, secondly, the method is not suitable for dangerous wastes containing easily reduced and volatilized heavy metals such as mercury and the like and high in chlor-alkali content, the kiln condition is influenced, and the applicable treatment capacity is generally very small.

(C) Combustible high-heat-value wastes such as powdery or fine granular anhydrated sawdust, animal feed, plastics and the like are conveyed to a kiln hood by a pipeline and sprayed into a rotary kiln for incineration. The method can save a large amount of fuel, but has high drying and crushing treatment cost.

(2) The method for pushing the kiln head/kiln tail into the rotary kiln for burning mainly comprises the steps of pushing large combustible waste such as rubber tires, and has high requirements on a feeding and pushing mechanism.

(3) The method for burning the combustible waste in the grate cooler in kiln head cover is characterized by directly burning the combustible waste in the grate cooler, so that the burning is easily influenced

The cooling quality of the material and the oxygen-containing concentration of secondary air entering the kiln and tertiary air entering the kiln are reduced, and the pulverized coal combustion and the kiln conditions of the kiln are influenced. The method is only suitable for heat-absorbing materials or low-heat-value materials and materials which need targeted pretreatment on contained heavy metals, chlor-alkali sulfur and the like.

(4) The method for co-processing the waste gas fed into the kiln tail smoke chamber comprises the following three modes: (A) and directly sending the crushed solid waste into a kiln tail smoke chamber for cooperative treatment. (B) Directly pumping the slurry material into a kiln tail smoke chamber for cooperative treatment. (C) The powdery material is directly sprayed into a kiln tail smoke chamber by pipeline compressed air for cooperative treatment. A common drawback of this type of process is: firstly, easily cause the material accumulation of kiln tail smoke chamber to glue stifled. And secondly, heavy metals in the solid waste are not subjected to reduction inhibition and pre-curing treatment, so that reduction volatilization of the heavy metals and volatilization of chlor-alkali sulfur are easily caused, the skinning of a smoke chamber, a throat and the like is aggravated, the stability of kiln conditions is influenced, and the heat consumption is increased. Because the kiln tail smoke chamber is an anoxic channel for communicating the rotary kiln with the upper decomposing furnace, the head coal which is not burnt out in time is accelerated to fly to the smoke chamber along with wind, and a small amount of coal dust particles also fall along with materials along with wind and star fire at the cone part of the upper decomposing furnace, so that the smoke chamber is always in a weak reducing atmosphere or a strong reducing atmosphere state. Thirdly, the combustible substances such as carbon-containing organic matters, sulfides and the like in the solid waste are not subjected to transitional reduction inhibition treatment, wherein the combustible substances can aggravate the reduction skinning of a smoke chamber and a throat.

(5) Sending the raw materials into a predecomposition furnace for a synergistic treatment method, which mainly comprises the following steps:

(A) and directly feeding the crushed carbon-containing organic solid waste serving as alternative fuel into the decomposing furnace from the inlet position of a tertiary air pipe of the decomposing furnace for cooperative treatment. The synergistic disposal mode is expected to preferentially heat and burn the solid waste by the high-temperature oxygen-containing tertiary air, but because the combustion performance of the carbon-containing organic solid waste is much poorer than that of fire coal, most of the carbon-containing organic solid waste contains a lot of adsorbed water and crystal water, the cold solid waste entering the decomposing furnace has poorer combustion performance, customers visually influence the combustion of pulverized coal in the decomposing furnace, most of the carbon-containing organic solid waste increase coal consumption, influence the working condition of a kiln system and increase the emission of heavy metals and pollutants in waste gas.

(B) The slurry hazardous waste or solid/plastic hazardous waste is smashed into slurry slag hazardous waste, and then oil substances are added and mixed, and the mixture is pumped into a decomposing furnace from a tertiary air pipe inlet position of the decomposing furnace as a substitute fuel for cooperative treatment. Although oil is added for supporting combustion and is added at an ideal position of a high-temperature oxygen-containing tertiary air port, the combustion performance of the carbon-containing organic matter solid waste is much lower than that of coal, most of the carbon-containing organic matter solid waste contains a lot of adsorbed water, combined water and free water, and the actual operation condition mostly influences the combustion of coal powder in a decomposing furnace, but increases the coal consumption, influences the working condition of a kiln system and increases the emission of heavy metals and pollutants in waste gas.

(C) The pretreated and dried combustible material is used as a substitute fuel and is put into the pre-decomposition furnace from the upper part (or the top) of the pre-decomposition furnace for cooperative treatment, and the pretreated and dried substitute fuel is generally combustible granular or powdery sawdust, filter soil, plastics, RDF, polluted soil, dried organic sludge, paper making sludge and the like which adsorb waste. The method can replace a large amount of tail coal, but the pretreatment and drying costs are high, most cement enterprises in China cannot bear the cost exceeding that of coal burning, and the secondary pollution problem in most pretreatment processes which is more troublesome is difficult to solve or extremely high in cost.

(6) The method is suitable for treating common solid waste to replace raw materials, and the dangerous waste which is not subjected to targeted effective pretreatment may have the hidden trouble of pollution diffusion of heavy metal/toxic harmful substances.

Obviously, the existing technology of using the carbon-containing organic hazardous waste as the alternative fuel has the defects.

Disclosure of Invention

The invention aims to solve the technical problem of overcoming the defects in the prior art and provides a method for preparing mixed fuel by using a cement plant to cooperatively process hazardous wastes containing organic matters, wherein the hazardous wastes containing organic matters can be cooperatively disposed by using a dry cement production line as alternative fuel, and simultaneously can be directly used as combustion improver (combustion improver) of coal-fired in the cement plant to promote clean combustion of coal powder.

The technical scheme adopted by the invention for solving the technical problems is as follows: a method for preparing mixed fuel by cooperatively processing hazardous wastes containing organic matters in a cement plant comprises the following steps:

(1) modification treatment: adding an oxidation promoter and a heavy metal ion stabilizer into the pre-treatment process of crushing, stirring and mixing or rolling and mixing hazardous wastes containing organic matters for modification treatment, and carrying out mixed reaction for 3-90 min to obtain a modified combustion-supporting material;

(2) preparing mixed fuel powder: continuously adding the modified combustion-supporting material obtained in the step (1) from the coarse powder feed back of the coal mill or continuously adding the modified combustion-supporting material from an inlet pipeline of the coal mill, and grinding the mixture into mixed fuel powder with 80um screen residue less than 3 percent and water content less than 1.5 percent;

(3) spraying into a kiln for combustion: and (3) sending the mixed fuel powder obtained in the step (2) into a cement kiln system to serve as head coal and/or tail coal fuel, and spraying the mixture into a kiln/furnace by a coal injection pipe to burn and fire clinker.

Further, in the step (1), the hazardous waste containing organic substances is one or a mixture of more than two of agroforestry, fishery, and pastoral hazardous waste, organic solvent-containing waste, mineral oil-containing waste, oil-water waste, hydrocarbon/water mixture waste, emulsion waste, polychlorinated (brominated) biphenyl waste, distillation residues, dye waste, coating waste, organic cyanide waste, phenol-containing waste and ether-containing waste, which can enter a coal mill and have a heat value of 600-8000 x4.18KJ/Kg.

Further, in the step (2), the adding amount of the modified combustion-supporting material is 1-80% of the mass of the raw coal, preferably 10-50%, and more preferably 10-30%.

Further, in the step (1), the oxidation promoter is at least one of ferrate, permanganate, percarbonate, fluorosulfonic acid, benzoic acid and its salt, naphthenic acid and its salt, and nitrate.

Further, in the step (1), the amount of the oxidation accelerator is 0.2-6%, preferably 1-5% of the mass of the hazardous waste containing organic substances. The addition of the oxidation accelerator is beneficial to promoting the oxidation and combustion of the carbon-containing organic matters, eliminating volatile peculiar smell and oxidizing heavy metal elements contained in the carbon-containing organic matters.

Further, in the step (1), the heavy metal ion stabilizer is at least one of sodium/potassium silicate, sodium/potassium metaaluminate, polyvinyl alcohol, sodium/potassium thiosulfate and phytic acid. The addition of the heavy metal ion stabilizer may initially stabilize the heavy metal and prevent the diffusion of contaminants during the pretreatment process.

Further, in the step (1), the amount of the heavy metal ion stabilizer is 0.3-8% of the mass of the hazardous waste containing organic substances.

Further, in the step (1), one or a mixture of more than two of lime, carbide slag, cement powder, slag powder, silicon powder, silica fume powder, calcium carbonate powder, bauxite, bentonite, zeolite powder, attapulgite powder and other carbon-containing organic compound materials can be added as auxiliary materials in the modification treatment process.

The invention has the beneficial effects that: (1) the process is simple, the investment is low, the hazardous waste material components are modified, the volatile peculiar smell is eliminated, the pollutants such as heavy metal and the like are stabilized, the pollutants such as the peculiar smell and the like possibly generated in the drying and grinding process are eliminated by utilizing the natural adsorption performance of the coal powder, and no secondary pollution is generated in the treatment process; (2) the hazardous waste containing organic matters is modified and treated to serve as a combustion promoting component (namely a combustion improver) and a substitute fuel of fire coal of a cement plant, and mixed and ground to prepare mixed fuel powder, so that clean combustion of hazardous wastes containing carbon organic matters and clean combustion of pulverized coal entering a kiln are facilitated, the fire coal can be effectively saved, environmental protection is facilitated, and sustainable development of green, low-carbon and circular economy is facilitated.

Detailed Description

The present invention will be further described with reference to the following examples.

The chemical reagents used in the examples of the present invention, unless otherwise specified, are commercially available in a conventional manner.

The following examples of the present invention relate to criteria including: DB 37/T1939-2011 is used for solid wastes in cement production, GB 18597-2001 standard for controlling pollution of storage of dangerous wastes, Standard Corrosion differentiation of dangerous wastes (GB 5085.1-2007), Standard Leaching toxicity differentiation of dangerous wastes (GB 5085.3-2007), Standard general rules of identification of dangerous wastes (GB 5085.7), Standard content differentiation of toxic substances of hazardous wastes (GB 5085.6), Standard reactivity differentiation of hazardous wastes (GB 5085.5), Standard Specification of identification of hazardous wastes (HJ/T298), and TCLP experiment detection of clinker by using a toxicity characteristic Leaching method.

The following examples were carried out on a phi 4 × 60m cement production line with a five-stage cyclone preheater predecomposition kiln drying method, and during normal production, the kiln tail smoke chamber, the throat and the kiln are moderately skinned and long-looped, about 10% of the reducing materials are contained in the clinker, and the stability of the kiln conditions is deviated. The average output of clinker under normal kiln conditions is 2678t/d, and the clinker output isThe actual standard coal consumption is 110.7kg/t, the vertical rise weight fluctuation of clinker is 1160-1330 g/L, the f-CaO fluctuation is 0.5-1.2%, the clinker strength fluctuation is 24.6-32.4 MPa in 3d compressive strength and 52.8-57.6 MPa in 28d compressive strength, the water demand fluctuation of standard consistency is 23-28%, the coagulation time fluctuation is 104-137 min in initial coagulation, 139-168 min in final coagulation, and chloride ions (Cl)^-) The content is 0.013%.