CN101215488A - Solid fuel mixed with organic waste and sludge and preparation method thereof - Google Patents

Abstract

The invention discloses a solid fuel mixed with organic garbage and sludge and a preparation method thereof. Solid fuel includes organic waste: 25% to 55%, sludge: 20% to 50%, coal powder: 20% to 50%, combustion accelerant: 0.15% to 0.25%, desulfurization and dechlorination agent: 0.5% to 2%. The preparation process includes three stages: raw material preparation, molding and consolidation. The invention has been tested on solid fuel mechanical strength, combustion characteristics, pollution control and the like. The solid fuel mixed with organic garbage and sludge obtained by the manufacturing method of the present invention is an ideal clean fuel, has high mechanical strength, meets long-distance transportation, and has a drop strength of more than 99%. It is a kind of solid fuel with strong mechanical properties. , non-polluting solid fuel with good water resistance, excellent combustion characteristics, and strong thermal stability can be extended to civil and industrial applications. And it can save a lot of non-renewable fossil fuels such as oil and coal, and has good social and environmental benefits.

Description

Solid fuel mixed with organic waste and sludge and preparation method thereof

【Technical field】

The invention relates to the technical field of domestic garbage and sludge resource utilization and environmental protection energy, in particular to a solid fuel capable of reducing, harmless and resourceful treatment of urban domestic garbage mixed with organic garbage and sludge and its preparation method.

【Background technique】

The annual output of "urban waste" in my country alone is nearly 150 million tons, and it is increasing at an annual rate of 7% to 9%. According to incomplete statistics, China's urban domestic waste has been piled up to more than 6 billion tons over the years, and about two-thirds of the cities are trapped in the predicament of garbage siege. The vast majority of urban waste is piled in the open air, which not only affects the urban landscape, but also pollutes the atmosphere, water and soil that are vital to our lives, posing a threat to the health of urban residents. Garbage has become a thorny problem in urban development. Existing methods for dealing with domestic waste include sanitary landfill except open-air stacking. Although sanitary landfill avoids the problems caused by open-air stacking, the landfill covers a large area, is used for a short period of time (usually about ten years), and is expensive. At the same time, the resources available in the garbage have not been recycled. In addition, another method of garbage disposal is incineration. Garbage incineration can reduce the volume of garbage by 50% to 95%, but at the same time, it also burns recyclable resources, releases toxic gases, such as dioxins, mercury vapor in batteries, etc., and produces toxic and harmful slag and dust . As for the composting method, it is necessary to separate the organic waste from other waste. These existing garbage disposal methods also all need high treatment costs. Disposing of a ton of waste generally costs hundreds of yuan, not including the cost of building a waste disposal site. For example, it takes 100-200 million yuan to build a large-scale waste landfill plant, and more than 2 billion yuan to build a large-scale waste incineration plant. For an urban waste incineration plant, excluding the cost of land acquisition and slag treatment, the investment of a 1,000-ton/day incineration plant is more than 700 million yuan, and the average operating cost is 70-150 yuan/ton of waste.

The average low calorific value of urban waste in my country is only about 600kcal/kg, which is lower than the minimum calorific value standard of 1000kcal/kg for furnace waste stipulated by the state. At present, there is no good incineration method for low-calorific-value garbage in the world, and the insufficient combustion of garbage causes a large amount of highly toxic and harmful substances in the exhausted smoke, which seriously pollutes the environment.

At present, a large amount of garbage that is landfilled or incinerated without classification is not only a huge waste of resources, but also produces secondary pollution. Not less than 33% of domestic waste can be directly recycled. Among the annual output of 150 million tons of urban waste, the value of discarded "renewable resources" is as high as 25 billion yuan!

Municipal solid waste is a complex mixture of various substances, consisting of coal ash, bricks, paper, plastics, metal, cabinet waste, wood chips and other wastes. Its components are mainly affected by the scale of urban development, climate, seasons, living standards and habits, and energy structure. With the improvement of residents' living standards and the change of food structure, especially the change of energy structure, the composition of municipal solid waste has undergone obvious changes, with low content of organic combustible components, high content of inorganic non-combustible components, and large fluctuations in garbage components; moisture content With high content and low calorific value, it is difficult to directly realize energy conversion, and the utilization rate of waste resources is low.

In addition to the difficult problem of municipal solid waste treatment, the amount of sludge (dry weight) discharged by my country's urban sewage treatment plants is about 1.3 million tons per year, and it is increasing at a rate of 10-20%. Especially in several cities and regions with a high level of urbanization in my country, the problem of sludge outlets has become very prominent. If all urban sewage is treated, the amount of sludge (dry weight) will be 8.4 million tons, accounting for 3.2% of the total solid waste in my country. How to dispose of such a large amount of sludge is a problem that many big cities will face. The main domestic sludge treatment methods mainly include landfill, incineration, direct drying, anaerobic digestion, and biological treatment. The landfill method is basically similar to urban waste landfill, which takes up a lot of land and wastes land resources; while the nutrients contained in the sludge cause a large number of disease and miscellaneous bacteria to multiply, resulting in mildew in the sludge and polluting the environment. According to the survey of domestic sewage treatment plants , The average cost of landfill treatment per ton of sludge is about 40 yuan/ton; the existing sludge incineration needs to consume a lot of heavy oil, which is not economical, and causes air pollution and wastes resources. For example, in Japan, sludge incineration accounts for more than 60% of the total sludge treatment, and most of the incineration processes use multi-stage incinerators. The cost of a set of incineration equipment with a processing capacity of about 50m3/d is as high as 2.8 billion yen; direct drying method can Dry the sludge with a moisture content of 75% to 80%, and the temperature is as high as 200°C to kill various germs, and then landfill or reprocess, but the energy consumption is high and the treatment cost is high; most of the active sludge before the 1980s Sludge is treated by anaerobic digestion to kill microorganisms and bacteria and produce some usable biogas. Relevant data show that the construction investment of the sludge anaerobic digestion system is about 1 to 2 million yuan/ton of dry mud, and the operating cost is about 700 to 900 yuan/ton of dry mud; the biological treatment method is the biocomposting method, which is the introduction of aerobic Bacteria and oxygen make sludge aerobic biological high-temperature fermentation. At present, the main methods of sludge treatment and disposal in my country account for about 44.8% for agricultural use, about 31% for landfill, about 10.5% for other disposal, and about 13.7% for non-disposal. According to statistics, the investment in sludge treatment and disposal in my country is about Accounting for 20-50% of the total investment of sewage treatment plants, sludge treatment and disposal are in a serious lagging state.

Domestic waste has low calorific value, high moisture content, large changes, difficult sorting, and the world's largest output. This reality is difficult to change in a short period of time. Surrounded by the three major constraints of waste status, economy and technology, how to make full use of waste resources and develop low calorific value waste resource efficient utilization technologies with my country's independent intellectual property rights has become a top priority. For example, Beijing currently produces 13,000 tons of garbage per day, with an annual output of 4.95 million tons, including 362,000 tons of waste plastics, 388,000 tons of waste paper, and 1.213 million tons of waste food and vegetation, and will increase at an annual rate of 8%. Garbage as a fuel resource can bring huge economic benefits.

【Content of invention】

The purpose of the present invention is to provide a solid fuel mixed with organic waste and sludge and its preparation method for the huge waste of recyclable resources in the existing urban waste and the high cost of waste incineration. Garbage is used as the main component of raw materials, and water-soluble wastewater sludge is used as a binder to realize the recycling, harmless and reduction treatment of solid organic waste.

The invention discloses a solid fuel mixed with organic garbage and sludge to achieve the above purpose. It is characterized in that the fuel is composed of organic waste, sludge and coal powder, and the weight percentages of the various components are: organic waste: 25% to 55%, sludge: 20% to 50%, coal powder: 20% to 50%, combustion enhancer: 0.15% to 0.25%, desulfurization and dechlorination agent: 0.5% to 2%.

The combustion aid can be one or a mixture of MnO ₂ or KMnO ₄ .

The desulfurization and dechlorination agent can be: CaO or one or a mixture of CaCO ₃ and MgO.

The invention also discloses a method for preparing solid fuel mixed with organic waste and sludge, which is characterized in that it comprises the following steps: drying and dehydrating the organic waste from which inorganic components such as heavy metals, brick slag, and tiles have been removed; Separately crush the coal and coal to a particle size of 3mm-10mm, and then fully mix the organic waste particles, coal powder particles, sludge, combustion accelerant and desulfurization and dechlorination agent in proportion, and the suitable moisture content is 8%-12%. Manual kneading, pressing and molding; natural drying of the shaped product to a moisture content of 5% to 15%.

The beneficial effect of the invention is that: the invention uses domestic garbage as a fuel resource, increases the content of combustible components by reducing the water content, and prepares solid fuel by optimizing the ratio of organic garbage, sludge, high calorific value coal powder, and the like. The solid fuel can achieve the best thermal efficiency, and the urban waste and sludge volume can be reduced at the same time. The preparation method of the invention is simple, the treatment cost is low, there is no secondary pollution, economic benefits can be obtained in a short period of time, and the solid organic waste can be recycled, harmless and reduced. Through adopting statistical analysis, quantitative theoretical analysis method to 256 experimental results, and means evaluation such as level effect and engineering effect evaluation, it is a kind of more ideal solid fuel that the organic refuse that obtains with the present invention's manufacturing method is mixed with sludge Clean fuel, with high mechanical strength, can fully meet the long-distance transportation, the drop strength is over 99%, and has strong moisture resistance and water resistance; the combustion calorific value meets the calorific value requirements of ordinary fuel utilization, and the degree of thermal stability High, can be a substitute for ordinary coal fuel, is a solid fuel with strong mechanical properties, good water resistance, excellent combustion characteristics, strong thermal stability, and no secondary pollution. It can be extended to civil and industrial applications to realize the recycling, reduction and harmlessness of garbage, and the recycling of garbage, which can save a lot of non-renewable fossil fuels such as oil and coal, and has good social and environmental benefits . And the troublesome sludge is directly treated and utilized, which not only solves the environmental pollution problem of wastewater sludge, but also turns waste into wealth and provides energy, which has important economic and social application value.

【Detailed ways】

The scheme adopted by the present invention: first remove heavy metals and inorganic components such as large brick slag and tiles in the garbage, which is the main raw material of organic garbage, which contains combustible organic components that are not easy to degrade naturally such as fabrics and plastics. Drying, coal powder, sludge and desulfurization and dechlorination agents are used as auxiliary materials, mixed into the pretreated organic waste, mixed and stirred in a wet state according to a certain component distribution ratio, and then pressed into a solid fuel product with a certain strength and shape. The best formula is obtained by optimizing the ratio, and the finished product can be used by civilians or enterprises.

The preparation process of the present invention involves three stages of raw material preparation, molding and consolidation.

The preparation of raw materials includes drying, crushing and mixing of raw materials. Due to the high moisture content of the collected domestic waste, in order to meet the moisture requirements of the briquette fuel, the organic waste that has removed heavy metals, large brick slag, tiles and other inorganic components is dried or dehydrated by natural air drying, and its moisture content is controlled at 4 % to 8%; then the pulverized coal and the dried household garbage are crushed into particles of 3mm to 10mm by ordinary crushing machinery; Fully mixed, in order to make the surface of the raw material particles evenly wetted by the sludge, cover the surface of the garbage and coal particles, achieve the best bonding effect, and make the combustion improver, desulfurization and dechlorination agent, etc. evenly distributed, which is convenient for raw material molding, suitable The moisture content is 8% to 12%.

The molding process is the second stage. After the prepared raw materials are mechanically or manually kneaded, they are sent to a molding machine at normal temperature and pressure (molding pressure 1961-3432N/cm ² ) to be pressed into solid fuel products of desired shape.

The third stage is the consolidation process, in which the molded samples are naturally dried to a moisture content of 5% to 15%.

During the preparation of the solution of the present invention, the provided garbage materials only need to sort out inorganic components such as heavy metals, large brick slag, tiles, etc., which can be easily solved manually or mechanically, and the main components are organic garbage. Waste plastics do not need to be sorted out and heat polycondensed, and there is no need for pyrolysis or dry distillation and carbonization during drying, and only natural drying can meet the preparation conditions. The proportion of high calorific value combustibles that are difficult to handle due to waste plastics and other waste treatment methods has increased, effectively solving the fundamental problem that the low calorific value of waste components hinders the increase in the calorific value of finished fuels. The combustible content is high, which can save a lot of fuel oil or coal. The sludge is a water-based binder, which has good cohesive force and is easy to knead evenly. Products can be produced by machinery, which can be widely used by residents and industries. Therefore, no matter in the process of raw material preparation or molding and consolidation, the invention is easy to operate, the fuel can be fully burned, and there is no secondary pollution caused by polluting gases such as SO ₂ and HCl.

The average low-level calorific value of urban waste in my country is only about 600kcal/kg, and its own heat energy is not enough to burn. It is necessary to increase the (heat) value of the original waste by precipitation or introduce economical external heat energy that is several times the heat value of the waste itself. Garbage burns stably and meets economic and environmental requirements. The present invention provides organic combustible garbage and sludge (sludge from urban sewage treatment plants) that can be fully utilized to manufacture solid fuel and its preparation method through raw material preparation, molding, and consolidation processes. The mechanical properties of the product provided by the invention , combustion characteristics and thermal stability all meet the technical indicators of briquette.

In the present invention, experiments are carried out on the fuel's combustion characteristics, thermal stability, and mechanical performance indicators such as compressive strength, drop strength, water immersion strength, and re-dry strength.

[Example 1]

Mix organic waste particles, sludge, and coal powder particles with a moisture content of 4% to 8% after drying in a ratio of 1:1:2, add a combustion aid MnO ₂ content of 0.18%, and a desulfurization and dechlorination agent CaO content of 0.90 %, mix evenly, and keep the moisture content at 8% to 12%; then knead and shape, and then dry naturally to a solid fuel product with a moisture content of 5% to 15%. The compressive strength of the solid fuel is measured by "Method for Determination of Cold Compressive Strength of Industrial Briquette" (MT/T748-1997), and the compressive strength of the solid fuel is determined to be in the range of 167.2620kPa to 207.0788kPa, with a reliability of 95%.

[Example 2]

Mix organic waste particles, coal powder particles, and sludge with a moisture content of 4% to 8% after drying in a ratio of 2:1:1, add a combustion aid MnO ₂ content of 0.17%, and a desulfurization and dechlorination agent CaO content of 1.20 %, mix evenly, and keep the moisture content at 8% to 12%; then knead and shape, and then dry naturally to a solid fuel product with a moisture content of 5% to 15%. After immersing the molded solid fuel product in water (at room temperature) for 24 hours, the water immersion strength of the solid fuel was measured using the "Measurement Method for Water Immersion Strength and Water Immersion Re-drying Strength of Industrial Briquettes" (MT/T749-1997). The water immersion strength of the solid fuel is in the range of 18.74458kPa to 23.484038kPa, and the reliability is 95%.

[Example 3]

Mix organic waste particles, coal powder particles, and sludge with a moisture content of 4% to 8% after drying in a ratio of 2:1:1, add a combustion aid MnO ₂ content of 0.18%, and a desulfurization and dechlorination agent CaO content of 1.20 %, mix evenly, keep the moisture content at 8% to 12%, then knead and shape, and then dry naturally to a solid fuel product with a moisture content of 5% to 15%. Using the "Measurement Method for Immersion Strength and Immersion Re-drying Strength of Industrial Briquettes" (MT/T749-1997) to measure the water-immersion and re-drying strength of the solid fuel, the water-immersion and re-drying strength of the solid fuel is determined to be in the range of 58.32095kPa～66.58751kPa , with a reliability of 95%.

[Example 4]

After drying, the organic waste particles, coal powder particles, and sludge with a moisture content of 4% to 8% are mixed in a ratio of 2:1:1, and the content of _MnO2 is 0.19%, and the content of desulfurization and dechlorination agent CaO is 0.90%. , mix evenly, keep the moisture content at 8% to 12%, then knead and shape, and then dry naturally to a solid fuel product with a moisture content of 5% to 15%. The thermal stability of the solid fuel was measured using the "Measurement Method for Thermal Stability of Coal" (GB/T 1573-2001), and the thermal stability of the solid fuel was determined to be in the range of 69.895% to 83.581%, with a reliability of 95%.

[Example 5]

Mix organic waste particles, sludge, and coal powder particles with a moisture content of 4% to 8% after drying in a ratio of 1:1:2, add a combustion aid MnO ₂ content of 0.19%, and a desulfurization and dechlorination agent CaO content of 1.20 %, mix evenly, and keep the moisture content at 8% to 12%; then knead and shape, and then dry naturally to a solid fuel product with a moisture content of 5% to 15%. The combustion calorific value of the solid fuel is measured by "Measurement Method for Calorific Value of Coal" (GB/T213-1996), and the calorific value of the solid fuel is determined to be in the range of 18.92722 to 19.51157 kJ/g, with a reliability of 95%.

[Example 6]

Mix organic waste particles, coal powder particles, and sludge with a moisture content of 4% to 8% after drying in a ratio of 2:1:1, add a combustion aid MnO ₂ content of 0.19%, and a desulfurization and dechlorination agent CaO content of 1.50% , mix evenly, and keep the moisture content at 8% to 12%; then knead and shape, and then dry naturally to a solid fuel product with a moisture content of 5% to 15%. The sulfur fixation rate of the desulfurizer (the percentage of sulfur content in ash to the sulfur content of solid fuel) is used to measure the control effect on polluted gases, that is, the method for the determination of total sulfur in coal (GB/T 214-1996) The sulfur content of the solid fuel and ash is measured, and the sulfur fixation rate of the solid fuel is determined to be in the range of 73.675% to 91.461%, and the reliability is 95%.

[Example 7]

Mix organic waste particles, coal powder particles, and sludge with a moisture content of 4% to 8% after drying in a ratio of 2:1:1, add a combustion aid MnO ₂ content of 0.17%, and a desulfurization and dechlorination agent CaO content of 0.80% , mix evenly, and keep the moisture content at 8% to 12%; then knead and shape, and then dry naturally to a solid fuel product with a moisture content of 5% to 15%. The dechlorination rate of the solid fuel is measured in the range of 57.761% to 91.601% by "Determination of Chlorine in Coal" (GB 3558-1996), and the reliability is 95%.

[Example 8]

Mix organic waste particles, coal powder particles, and sludge with a moisture content of 4% to 8% after drying in a ratio of 2:1:1, add a combustion aid MnO ₂ content of 0.18%, and a desulfurization and dechlorination agent CaO content of 1.50% , mix evenly, keep the moisture content at 8% to 12%, then knead and shape, and then dry naturally to a solid fuel product with a moisture content of 5% to 15%. The compressive strength, water immersion strength, water immersion and re-drying strength, thermal stability and combustion calorific value of the solid fuel were respectively measured by the above method. It reaches 59.78425kPa, the thermal stability index TS ₊₆ value is 62.98%, the combustion heat value is 18.27323kJ/g, the sulfur fixation efficiency can reach 78.44%, and the chlorine fixation efficiency can reach 77.71%.

Claims (6)

1. organic waste and mud blended solid fuel, it is characterized in that described fuel comprises organic waste, mud, the coal dust composition that is mixed, the weight percent of described various compositions is: organic waste: 25%～55%, and mud: 20%～45%, coal dust: 20%～45%, ignition dope: 0.15%～0.25%, desulfurization dechlorinating agent: 0.5%～2%.

2. organic waste according to claim 1 and mud blended solid fuel is characterized in that described ignition dope is: MnO ₂Or KMnO ₄In a kind of or mixture.

3. organic waste according to claim 1 and mud blended solid fuel and preparation method thereof is characterized in that described desulfurization dechlorinating agent is: CaO or CaCO ₃, a kind of or mixture among the MgO.

4. described organic waste of claim 1 and the solid-fuelled preparation method of mud blended, it is characterized in that may further comprise the steps: the organic waste drying and dehydrating that will remove heavy metal and brick slag, tile inorganic components, organic waste and coal are crushed to 3mm～10mm particle diameter respectively, with organic waste particle, pulverized coal particle, mud, ignition dope and desulfurization dechlorinating agent thorough mixing in proportion, keeping moisture content is 8%～12% again; Pinch compression moulding through machinery or artificial mixing; With the moulding product seasoning to moisture content 5%～15%.

5. organic waste according to claim 4 and the solid-fuelled preparation method of mud blended is characterized in that the dehydration of described organic waste drying or natural air drying, and moisture content is controlled at 4%～8% behind the drying and dehydrating.

6. organic waste according to claim 4 and the solid-fuelled preparation method of mud blended is characterized in that described compression moulding process is under normal temperature, condition of normal pressure.