KR101269391B1 - Pulverized fuel and method for production of the same - Google Patents

Abstract

The present invention relates to a fine fuel and a method for producing the same, which can obtain the effect of stabilizing combustion efficiency and reducing combustion gas emissions by including pulverized green coal and biomass.

Description

Fine fuel and its manufacturing method {PULVERIZED FUEL AND METHOD FOR PRODUCTION OF THE SAME}

The present invention relates to a fine fuel and a method for producing the same, which can obtain the effect of stabilizing combustion efficiency and reducing combustion gas emissions by including green coal and biomass finely ground to the same particle size.

Coal has occupied more than 24% of the world's energy sources until recently, but its use is gradually decreasing in Korea, unlike advanced countries, due to the negative view that it is not environmentally friendly due to the emission of environmental pollutants.

However, with the recent surge in oil prices, the current technology is reaching a limit that it is difficult to secure new energy sources such as solar energy and bioenergy that can replace crude oil. to be.

Coal is widely distributed all over the world, so not only can we expect a stable supply in the long run, but also considering the increase in demand, it is rich in resources. There is an advantage.

Currently, coal relies on imports for most of the bituminous coal used in the industry, except for small amounts of anthracite coal produced in Korea. Imported bituminous coal requires a separate heat source for initial ignition when used in a heater such as a farmhouse, and it is not easy to adjust thermal power, and it is not easy to change the temperature of the heater according to the greenhouse temperature.

Therefore, in view of economics and supply and demand stability of logistics, it is urgently required to develop new coal raw materials to replace bituminous coal.

Meanwhile, amid concern about global warming and the depletion of fossil resources, biomass, the second most abundant energy source after coal and oil, is drawing attention as a new energy source.

Biomass refers to the mass of biomass, and refers to organic materials of biological origin that can be used as energy resources and raw materials. Biomass is a "renewable" organic resource produced from mineral water and carbon dioxide by photosynthesis using solar energy. Also, since the carbon dioxide released when burning biomass is the same as the carbon dioxide absorbed into the atmosphere by photosynthesis during biogrowth, biomass does not increase the carbon dioxide concentration in the atmosphere during its life cycle. 'Has characteristics.

Therefore, if the energy or products derived from fossil resources are replaced with biomass, the greenhouse gas (carbon dioxide) emission that causes global warming can be greatly reduced, and the sulfur content is low, so when mixed with high sulfur coal, SO ₂ The effect of reducing occurrence can be obtained. Biomass is more economical than bituminous coal and is continuously increasing with fossil fuel consumption due to rapid economic development.

Biomass can be obtained from municipal biomass obtained from woody biomass, sugarcane, fruit juice obtained from trees and the like, starchy biomass obtained from sweet potatoes, biomass of photosynthetic bacteria, food waste, etc. And biomass to be obtained. Among these, woody biomass can be produced in three forms of solid, liquid, and gas and can be used for heat and power transportation fuel. Examples of the solid woody biomass include wood chips, wood pellets, woody brackets and charcoal. Examples of the liquid woody biomass include bio-oil and bio-ethanol. Examples of the gaseous biomass include Is syngas.

The wood-based biomass is an environmentally friendly fuel capable of reducing SO ₂ generation due to its low sulfur content. In particular, when mixed with high sulfur coal, the alkali material contained in the biomass can be expected to remove SO ₂ , and the nitrogen content of the biomass is converted to NH radicals during combustion, thereby reducing NO. It is reported to have the effect of removing NO _x since it is used to remove. However, wood-based biomass generally has a low calorific value as low as 6 to 70% of coal, and the raw biomass has a high porosity inside the material.

As a way to remedy these shortcomings, a mixture of coal and wood biomass has been developed. For example, Patent Literature 1 discloses 45-80% by weight of anthracite coal for heat generation and 15-45% by weight of paper waste sludge, which is an industrial waste generated from a paper mill for heat generation, and a liquid oyster shell with sterilization and odor remover. The ball-coal using the papermaking sludge which consists of 3.0-7.0 weight% of a solution and 2.0-3.0 weight% of loess as a caking additive for improving caking power is disclosed, and patent document 2 based on the composition total weight of a wood pellet 30- A solid fuel composition comprising 50 parts by weight and 70 to 50 parts by weight of anthracite powder is disclosed. Patent Document 3 discloses 45 to 99% by weight of bituminous coal, 0.1 to 25% by weight of petroleum coke, 0.1 to 10% by weight of heavy oil ash, and A fuel composition for the production of cement clinker using waste sludge, sawdust or a waste containing 0.1 to 20% by weight thereof is disclosed.

However, the literature reviewed so far shows that during the mixed combustion of most coal / biomass, many of the volatiles contained in the biomass can cause flame instability, and slagging due to the low melting temperature of the ash In addition, there is a disadvantage in that fouling (fouling) occurs, the existing power plants use only a limited amount of the mixed situation. In particular, the boiler using wood pellets, one of the wood-based biomass, is greatly reduced in combustion efficiency during the use process, and also is not used properly due to poor fuel supply.

Therefore, while overcoming the disadvantages of the fuel mixture of the conventional coal and biomass, the research on the development of fine fuel that can be used in a general boiler combustion apparatus, such as for farms, has emerged.

Republic of Korea Patent Publication No. 2006-26471 Republic of Korea Patent Publication No. 2010-58741 Republic of Korea Patent Publication No. 2010-130443

In order to solve the conventional problems as described above, the present invention includes green coal and biomass with increased calorific value, which improves the emission of harmful gases generated during the combustion of bituminous coal, thereby stabilizing the ignition rate and the combustion efficiency, and exhausting the combustion gas. An object of the present invention is to provide a fine fuel and a method for producing the same that can obtain a substance reducing effect.

Differential fuel

In order to achieve the above object, in the present invention

80 to 90% by weight of green coal having 1% by weight or less of water, 3 to 20% by weight of volatile matter, 15% by weight or less of ash, 70 to 85% by weight of fixed carbon, and 0.5% by weight of sulfur,

It provides a fine fuel comprising 10 to 20% by weight of semi-carbonized biomass.

At this time, in the specification of the present invention, the term 'below' is preferable when the value is less than or equal to the upper limit defined in the specification, and is described as meaning that the technical significance of the present invention is limited to the limited upper limit only, and the lower limit is more than 0 (that is, even a trace amount). Must be included).

In the fine fuel of the present invention, when the mixing ratio of the semi-carbonized biomass is more than 20% by weight, excessive volatile content stabilizes the combustion rate and the combustion efficiency in the coal boiler, and reduces the emissions of the combustion gas. Difficult to satisfy the effect. In addition, if the mixing ratio of the semi-carbonized biomass is less than 10% by weight, the initial ignition rate is lowered, the content is insufficient, there is a disadvantage that it does not solve the problems of general coal, such as semi-coke or anthracite coal.

The calorific value of the fine fuel of the present invention is 7,000 Kcal / Kg, preferably 7,200 Kcal / Kg or more.

In the fine fuel of the present invention, the green coal is 15% by weight or less of the raw coal, and has a calorific value of 6,000 Kcal / kg or more on anhydrous basis, 35-40% by weight of volatile matter, 10% by weight or less of ash, and 0.5% by weight of sulfur. It is produced using bituminous coal which is% or less. At this time, the bituminous coal is not particularly limited to coking coal and non-coking coal, but is more preferable in the case of non-coking coal.

In the fine fuel of the present invention, the biomass may use any one selected from the group consisting of woody biomass, rice hull, or combustible household waste. For example, volatile matter and moisture are higher than coal, and nitrogen, ash and Low sulfur content, low environmental pollution, high K ₂ O, CaO in ash, fuel ratio (fixed carbon / volatile matter) is about 0.2, less than 1/10 of coal. Preference is given to using.

In order to use the wood-based biomass as an energy source, it is required to undergo direct combustion, thermochemical conversion (solid fuelization, liquefaction, gasification), and biological conversion (biorefining). The simplest way to process wood into fuel is to grind it into wood chips or sawdust. On the other hand, while fuel chips and the like are simple to process, they have disadvantages of high water content, non-uniformity and quantity. Therefore, in the present invention, in order to improve the disadvantage that the production capacity during the grinding process for the subsequent micronization of the biomass used for fine fuel to reduce the production capacity during the grinding to the desired particle size, further drying and semi-carbonization process before grinding It is desirable to. Through this process, the moisture and high temperature volatilization content of the biomass raw material is reduced, and the specific gravity is increased to facilitate the subsequent grinding process. In other words, biomass raw materials were 8.62% moisture, 70.14% volatile matter (LOI), 0.95% ash, 20.18% fixed carbon, and the carbon content was 50.87%. The hydrogen content was 5.87%, the oxygen content was 40.48%, the nitrogen content was 0.28%, and the sulfur content was 0.1%, and the calorific value was about 4,660 kcal (dry basis). However, the content of wood-based biomass after semi-carbonization was 0.75% of water, 63.38% of volatile matter (LOI), 0.96% of ash, and 35.65% of fixed carbon.The results of chemical analysis showed 83.25% of carbon, 1.02% of hydrogen, Nitrogen content was reduced to 0.1%, sulfur content 0.1%, the calorific value was found to increase to about 5,650 kcal (dry basis).

In addition, in the fine fuel of the present invention, the fine fuel is a fine powder having a particle size of 200 mesh or less, for example, a fine powder having a particle size of 100 to 200 mesh in order to maximize combustion efficiency when applied to a boiler or the like. It is preferably made up of 90% by weight to 93% by weight of fine powder having a particle size of 200 mesh or less.

In the case of the conventional biomass, since the porosity inside the material is very high in the raw state, it is difficult to handle such as the large volume and the transportation efficiency is significantly lower than that of coal. In contrast, the fine fuel comprising the green coal and the semi-carbonized biomass of the present invention is composed of fine powder having a particle size of 200 mesh or less, thereby improving transport and storage properties. In addition, the fine fuel of the present invention can be easily mixed by increasing the air permeability and smooth oxygen supply because the fine powder having an increased surface area is mixed at a predetermined ratio.

In addition, the fine fuel of the present invention can prevent spontaneous ignition by blocking the contact with oxygen by the surface (coating) treatment with a surface coating material.

The surface coating material used in the surface (coating) treatment is not particularly limited as long as it is burned at a low temperature, hardly reacts with moisture, and has a low viscosity and a high coating rate to block the contact surface between air and fine fuel. Specific examples include, but are not limited to, solid paraffin or stearic acid. In general, paraffin is weak in reactivity and resistant to chemicals. Paraffin is a colorless and translucent solid and is called solid paraffin and stone wax paraffin. The degree of refinement of the tablet indicates various melting points depending on the components and the like, and is in the range of 47 to 65 ° C. The main component consists of a straight-chain paraffinic hydrocarbon CH ₃ (CH ₂ ) _n CH ₃ , preferably having from 16 to 40 carbon atoms, for example, 20 to 30 carbon atoms. The surface coating material of the present invention is preferably applied to 1 to 2% by weight relative to the total weight of the fine powder. At this time, even if 2 wt% of the surface coating material is applied, almost the same effect as the case of applying 1 wt% is obtained, and the content of solid paraffin suitable for fine fuel coating is a minimum content, that is, an appropriate amount of 1 wt% is used for cost reduction. It is preferable that it is%.

Manufacturing method of fine fuel

In order to achieve the above object, in the present invention

Drying the mined raw coal;

Indirect air at 500-800 ° C Preparing a green coal by performing a heating and pyrolysis process;

Injecting the biomass raw material into the closed, high temperature drying furnace, and drying the biomass to produce a semi-carbonized biomass;

Mixing the green coal and the semi-carbonized biomass; And

It provides a method for producing fine fuel comprising the step of pulverizing the mixed green coal and semi-carbonized biomass to produce a fine fuel (see FIG. 1).

At this time, the raw coal is preferably 15% by weight or less of anhydrous reference calorific value 6000 Kcal or more, volatile matter 35-40% by weight, ash 10% by weight or less, sulfur content 0.5% by weight or less is preferable. At this time, the bituminous coal is not particularly limited to coking coal and non-coking coal, but is more preferable in the case of non-coking coal.

First, since mined raw coal contains adhered moisture, intrinsic moisture, and bonded moisture, it is necessary to carry out a drying process. At this time, the adhered moisture is mechanically attached to the coal, and refers to the moisture that is evaporated and disappeared when the coal is thinned indoors and dried at room temperature. Intrinsic moisture is due to the colloidal hygroscopicity of coal, and refers to moisture that is lost when dried at 105 ° C. after removing the adhered moisture. Bound moisture is moisture in chemically bound form and refers to moisture released at about 300 to 500 ° C. when coal is dried without being evaporated at 105 ° C. The water content of coal in this moisture is the sum of the adhesion moisture and the intrinsic moisture. Coal is typically added artificially with a certain amount of moisture to prevent dust blowing during transportation, usually having a water content of 5-15% of the total weight of coal.

Specifically, in the present invention, by spreading the mined raw coal containing a certain moisture thinly in a large space as a natural dry or using a facility such as a rotary dryer using steam, such as a moisture content of 5 to 15% by weight or less, Preferably it is dried to have 5 to 7% by weight.

At this time, if the moisture content exceeds 15% by weight in the raw coal drying process, the temperature rise in the furnace is delayed due to the use of a heat source for initial excessive moisture evaporation, so that the thermal decomposition rate such as the removal of volatile components is lowered. You will not be able to get it. In addition, when the moisture content is less than 5% by weight, it is difficult to not only environmental aspects but also worker's work due to fine powder flying during transportation and charging.

Subsequently, green coal is manufactured by heating raw coal having an appropriate amount of water content under air-tight sealing conditions at 500 to 800 ° C. using a multi-stage energy-saving rotary kiln facility of an indirect heating method under a sealed structure. In this case, when the heating temperature is less than 500 ° C., it is difficult to expect a gas generation reduction effect during combustion because a large amount of volatile matter is not removed. In addition, when the excess amount of volatiles is removed in excess of 800 ℃ it is difficult to ignite during combustion, it is not economical due to rising fuel costs.

Specifically, the raw coal having an appropriate amount of water is charged into the rotary kiln inlet charging hopper, and the charged dry raw coal is continuously transferred into the kiln (part of the rotary kiln in the combustion chamber) through a screw feeder. The pyrolysis process of raw coal is performed by indirect heating method by composing a combustion chamber composed of iron case, refractory, and burner outside the rotary kiln. The pyrolysis process according to temperature during the low temperature drying of raw coal charged into the rotary kiln is as follows.

(1) 25 to 100 ° C .: During the natural drying process, most of the adhered moisture is removed, and some of the remaining adhered and intrinsic moisture evaporates. Moisture is most separated at 60-80 ° C, uniformly separated little by little above 80 ° C, and separation is almost stopped at 105 ° C.

(2) 100-200 degreeC: Separation of the occlusion gas (hydrocarbon) absorbed in solid inside arises.

(3) 200-300 degreeC: Decomposition of the less coaled coals, such as lignite, begins. Upon decomposition, bound water, CO ₂ and CO are separated in the oxygen compound, and H ₂ S is separated in the organic sulfur compound.

(4) 300-400 degreeC: The coal decomposition of bituminous coal and anthracite coal starts. Coking coal is first melted and decomposed at 310 to 320 ° C, and after decomposition, gases such as H ₂ O, CO ₂ , CO, and H ₂ S and red tar and hydrocarbons having low viscosity start to separate.

(5) 400 to 500 ° C: NH ₃ starts to decompose from nitrogen oxides, and tar separation occurs most vigorously. Minerals also begin to decompose, and CO ₂ begins to separate from CaCO ₃ .

_{(6) 500~600 ℃: H 2} O, Co generation of the gas is stopped, and is actively separated C _m H _n, H ₂ and CH _4, the tar also continues to be isolated from large amounts.

(7) 600 to 700 ° C: C _m H _n is decomposed to generate CH ₄ , a part of tar is decomposed to a gas, and a part is changed to aromatic.

(8) 700 to 800 ° C .: C _m H _n Thermal decomposition of gas and tar results in H ₂ and CO generation. The gas generated during the pyrolysis of the raw coal is transferred back into the combustion chamber along the gas line and used as a heat source for coal pyrolysis, thereby reducing fuel costs. As the rotary kiln rotates, the raw material in the furnace slowly moves in the direction of the exit and exits the kiln (part of the rotary kiln inside the combustion chamber) through a screw feeder, as installed at the inlet.

In this case, the method for producing fine fuel according to the present invention includes cooling the coal heat-treated in a kiln (rotary kiln portion inside the combustion chamber) for a predetermined time after manufacturing the green coal to be below a predetermined temperature to prevent spontaneous ignition before being discharged to the outside. Need more. The rotary kiln portion (outlet) outside the combustion chamber is surrounded by cooling equipment such as a water cooling jacket, thereby cooling the temperature of the discharged coal to 50 ° C or lower. Subsequently, the green coal cooled by a cooling facility such as a water cooling jacket is discharged to the outside through a rotary valve provided at the lower end of the rotary kiln outlet.

The raw coal, which has undergone a series of processes (drying, pyrolysis, cooling), has a calorific value of 7000 kcal / kg or more, 1% by weight or less of moisture, 3 to 20% by weight of volatile matter, 15% by weight or less of ash, 70 to 85% by weight of fixed carbon, and sulfur content. It is made of green coal of 0.5 wt% or less.

In addition, in the present invention, the biomass raw material is introduced into a closed, high temperature drying furnace and pyrolyzed under a temperature condition of 300 to 350 ° C. to produce dry and semi-carbonized biomass.

At this time, the main equipment used for the drying and carbonization of biomass is a high temperature drying furnace, generally a rotary kiln type as an external heat drying furnace, and a hot air furnace type as a heat resistant drying furnace. In the present invention, a semi-carbonization process is performed using an external heat type vertical furnace.

Specifically, the wood-based biomass raw material is charged to a carbonization chamber that can be sealed, and then sealed and heated to the target temperature by applying heat from the outside. Wood-based biomass is subjected to a pyrolysis atmosphere for about 2 hours at a furnace temperature of 300 ° C. in a high temperature drying furnace. During the pyrolysis process, the dry gas contained in the biomass is volatilized and the remaining wood-based biomass is semi-carbonized. The generated dry gas can be reused as a heat source because it is generated by mixing of flammable gas. The weight of the semi-carbonized biomass after pyrolysis is reduced to 40-45% of the weight of the raw material as the moisture and volatiles are removed.

Subsequently, the obtained green coal and semi-carbonized biomass are mixed at a ratio of 80 to 90 wt%: 10 to 20 wt%, and then the mixed green coal and semi-carbonized biomass are pulverized.

The equipment used for the grinding process is a tube mill (ball mill) type grinding apparatus, which puts balls of different sizes of steel material into the cylindrical grinding vessel together with the grinding raw material, and then rotates the ball about the vertical axis of the cylinder. It is a facility that grinds into fine powder by friction action of raw materials and has a production capacity of about 400kg / hr. The final fine fuel obtained by such a grinding process should be composed of 90% or more with a particle size of 200 mesh or less (75 μm) of a standard body, and specifically, a fine powder between 100 and 200 mesh (150 to 75 μm) is about 7 to 10%, It is preferable that the fine powder of 200 mesh (75 micrometers) or less consists of about 90 to 93%. As such, the fine fuel of the present invention may be easily mixed in a boiler by increasing the surface area of the finely divided fine components to increase the air permeability and smooth oxygen supply.

On the other hand, in general, coal absorbs oxygen in the air and oxygen in moisture (H ₂ O) in contact with coal, and a phenomenon of spontaneous ignition occurs in which heat is gradually generated. In addition, the coal powder has a large specific surface area and a large contact area with oxygen, resulting in high rate of spontaneous ignition (increased oxidation rate).

Therefore, in the present invention, in order to prevent the fine fuel from contacting with oxygen to prevent spontaneous ignition of the fine fuel, when mixing the green coal and the semi-carbonized biomass, a solid surface coating material is mixed together, and then the green When finely pulverizing coal and semi-carbonized biomass, it is desirable to allow the surface coating to be ground (coated) with the fine coating of the fine powder.

At this time, the surface coating material is not particularly limited as long as it burns at a low temperature, hardly reacts with moisture, and has a low viscosity and a high coating rate to block the contact surface of air and fine fuel, but for example, solid paraffin Or stearic acid is preferable. In addition, the surface coating material of the present invention is preferably applied 1 to 2% by weight based on the total weight of the fine powder, more preferably 1% by weight of the proper amount of use.

As described above, the char carbonized semi-carbonized wood-based biomass used in the production method of the finely divided raw material of the present invention starts the combustion reaction at 400 ° C or lower, and the green coal starts the combustion reaction at the temperature of 600 ° C or lower. Therefore, the combustion reaction is started at a temperature of about 200 ° C. lower than that of the green coal, indicating that the wood-based biomass car is a relatively good fuel for combustion than the green coal. Therefore, when the fine fuel mixed with the green coal and the wood-based biomass car is mixed at a predetermined ratio, the initial combustion power and the combustion reaction speed due to the mixed properties of the two fuels can be increased. In addition, the fine fuel of the present invention has a calorific value (7000 kcal / kg or more) suitable for the boiler combustion device, and can improve the combustion atmosphere in the combustion furnace can bring about stabilization of combustion speed and combustion efficiency.

In addition, the fine fuel of the present invention can be prepared by mixing the green coal and semi-carbonized biomass of the clean raw material of solid fossil raw materials to increase the initial combustion power and the combustion reaction speed due to the mixed characteristics of the two fuels, and the continuous combustion In addition to maintaining the stabilization of efficiency, it is possible to significantly reduce the emission concentrations of air pollutants by reducing the emissions of SO _x and carbon dioxide relative to the calorific value during boiler operation. Therefore, the development and use of fine fuels expands the range of coal utilization and develops them into eco-friendly and economical fuels, thereby reducing the dependence on oil, which accounts for more than 40% of domestic energy sources, and stably fueling ordinary people's fuels even when energy prices such as high oil prices rise. We have established a foundation to supply.

In the present invention, by providing a fine pulverized fine fuel comprising green coal and semi-carbonized biomass, while having a suitable calorific value in the boiler combustion apparatus, it is possible to satisfy the conditions of stabilizing combustion speed and combustion efficiency, and reducing combustion gas emissions. there was. Therefore, it is possible to establish a stable supply base for the coal-based industry and to supply the common people fuel stably even when energy prices such as high oil prices rise.

1 is a manufacturing process diagram of the fine fuel of the present invention.
Figure 2 is a graph showing the temperature change of the fine fuel coated with 0.5% solid paraffin obtained from Comparative Example 13.
3 is a graph showing the temperature change of the fine fuel coated with 1% solid paraffin obtained from Example 17. FIG.
4 is a graph showing the temperature change of the fine fuel coated with 2% solid paraffin obtained from Example 18. FIG.

Hereinafter, although an Example demonstrates this invention concretely, it is not limited to these Examples at this invention.

I. Green coal  Produce

Examples 1-12 and Comparative Examples 1-6

Manufactured with mined bituminous coal (non-coking coal) (water content 10%, volatility 35.40%, ash 8.21%, fixed carbon 56.39%>, sulfur 0.48%) and dried naturally for more than 24 hours to produce 5% moisture content. It was. Prior to charging the raw material, the rotary kiln was heated to a firing temperature at a rate of 5 ° C./min. After the temperature of the rotary kiln was completed, dried bituminous coal (non-coking coal) contained in a ton bag was charged into the rotary kiln inlet charging hopper at 400 kg per hour. The charged coal was transferred into the kiln through a screw feeder. At each test firing temperature, the pyrolysis was performed for a period of time while changing the holding time of the furnace by adjusting the rotation speed of the rotary kiln. After the pyrolysis was completed, the water was cooled to 50 ° C. or lower by a water cooling jacket provided outside the rotary kiln outlet, and the green coal obtained through the rotary valve was discharged to the outside. At this time, the amount of green coal discharged to the outside was adjusted to 240kg per hour. The quality of green coal obtained under each pyrolysis condition is shown in Tables 1 and 2 below. At this time, moisture, volatile matter, ash, and fixed carbon of green coal were calculated by industrial analysis method, sulfur by C / S analysis, and calorific value by industrial analysis result. In addition, the number of samples used for each analysis was 10EA, and the average value was shown.

Exam conditions Green Coal Quality Example Firing temperature
(℃) Charging
Discharge time
(time) moisture
(%) Anhydrous standards sulfur
(%) Calorific value
(kcal / kg) Volatility
(%) Ash
(%) Fixed carbon
(%) One 500 One 0.99 19.78 10.20 70.02 0.47 7476 2 600 0.90 17.35 10.50 72.15 0.46 7436 3 700 0.84 14.99 10.80 74.21 0.43 7393 4 800 0.77 11.52 11.24 77.24 0.43 7326 5 500 2 0.87 17.12 10.53 72.35 0.44 7434 6 600 0.82 15.88 10.69 73.43 0.42 7413 7 700 0.73 13.56 10.99 75.45 0.42 7371 8 800 0.59 9.76 11.47 78.77 0.38 7297 9 500 3 0.75 16.37 10.63 73.00 0.46 7429 10 600 0.73 14.58 10.86 74.56 0.45 7393 11 700 0.64 11.01 11.31 77.68 0.41 7322 12 800 0.29 6.41 11.89 81.70 0.38 7229

Exam conditions Green Coal Quality Comparative example Firing temperature
(℃) Charging
Discharge time
(time) moisture
(%) Anhydrous standards sulfur
(%) Calorific value
(kcal / kg) Volatility
(%) Ash
(%) Fixed carbon
(%) One 300 2 1.52 30.21 8.87 60.92 0.49 7553 2 400 1.11 26.70 9.32 63.98 0.48 7568 3 900 0.25 2.50 12.39 85.11 0.37 7136 4 300 3 1.50 26.88 9.29 63.83 0.48 7505 5 400 1.00 23.29 9.75 66.96 0.48 7523 6 900 0.22 1.86 12.47 85.67 0.36 7120

As shown in Tables 1 and 2, when the raw coal (coal briquettes) is heated and pyrolyzed at 500 ° C. or lower, volatiles are not removed, and thus a large amount of volatiles are hardly expected. In addition, when the raw coal (coal briquettes) is heated and pyrolyzed at 800 ° C. or higher, excess volatiles are removed, which may cause difficulty in ignition in subsequent combustion.

II. Preparation of Biomass

Example  13-14 and Comparative example  7-8

The wood-based biomass raw material was charged into a sealable carbonization chamber and then sealed, and a semi-carbonized biomass was manufactured through a pyrolysis atmosphere in a temperature condition of Table 3 below for about 2 hours (see Table 3 below).

Exam conditions Biomass quality Semi-carbonization
Temperature
(℃) moisture
(%) Anhydrous standards carbon
(%) Hydrogen
(%) sulfur
(%) Calorific value
(kcal / kg) Volatility
(%) Ash
(%) Fixed carbon
(%) Biomass raw materials - 8.62 70.14 0.95 20.18 50.87 5.87 0.1 4,600 Example 13 300 0.75 63.38 0.96 35.65 68.98 4.97 0.08 5,650 Example 14 350 0.7 61.22 0.98 37.78 70.13 4.97 0.08 5,740 Comparative Example 7 200 1.9 68.21 0.95 30.84 66.88 5.01 0.1 4,950 Comparative Example 8 500 0.34 15.45 2.27 82.28 83.25 1.02 0.08 6,550

III. Manufacture of fine fuel

Example  15-16 And Comparative example  9-12

The green coal obtained in Example 6 and the biomass obtained in Example 13 together with the steel balls (diameter 10 to 80 mm) in a cylindrical grinding vessel as a tube mill (ball mill) type grinding apparatus are shown in Table 4 below. After mixing at the mixing ratio indicated, the ball and the raw materials were rotated about the vertical axis of the cylinder to rub the balls and the raw materials to obtain 10% fine powder of 100-200 mesh particle size and fine powder of 200 mesh or less (-75㎛). A fine fuel consisting of 90% was prepared. Table 4 shows the quality of the fine fuel according to each mixing ratio.

Mixing ratio
(Semi-carbonized
Biomass: Green Coal) Industrial analysis (%) Chemical analysis (%) Calorific value
(kcal / kg) moisture Volatility Ash fixing
carbon carbon Hydrogen Oxygen nitrogen sulfur Example 15 10: 90 0.56 19.62 8.65 71.28 78.97 3.33 15.75 1.50 0.46 7252 Example 16 20: 80 0.57 24.24 7.80 67.56 77.99 3.51 16.74 1.34 0.42 7084 Comparative Example 9 8: 92 0.56 14.92 8.91 75.41 80.21 2.98 14.81 1.53 0.47 7350 Comparative Example 10 30: 70 0.59 28.87 6.94 63.83 7.00 3.70 17.74 1.19 0.38 6916 Comparative Example 11 40: 60 0.60 33.49 6.09 60.11 76.02 3.88 18.73 1.03 0.34 6748 Comparative Example 12 50: 50 0.62 38.11 5.24 56.39 75.04 4.06 19.73 0.88 0.30 6580 Mined coal - 10 35.40 8.21 56.39 78.66 2.87 14.03 1.04 0.48 5800 Reflection coke - 2 to 4 6 6 to 8 80 to 85 84.84 3.10 15.27 1.10 0.35 to 0.46 7100

Referring to Table 4 above, in the case of fine fuel containing green coal and semi-carbonized biomass, the solid fossil raw material has a high calorific value compared to mined coal, and thus has a high calorific value. If the biomass content ratio exceeds 20% by weight, it does not meet the high calorific value of fine fuel equivalent to semi-coke, and the process loss due to the scattering of semi-carbonized biomass, which is relatively light in the combustion process. It tends to decrease the efficiency of use relatively. Table 5 shows the measurement of the fuel loss rate according to the mixing ratio. In this case, the fuel loss rate was estimated by dividing the weight of the fixed carbon in the fine fuel by the weight of the fixed carbon in the dust collected in the outside air.

Mixing ratio
(Semi-carbonized biomass: green coal%) Fuel loss rate (%) Example 15 10: 90 2.4 Example 16 20: 80 2.8 Comparative Example 10 30: 70 3.3 Comparative Example 11 40: 60 4.0 Comparative Example 12 50: 50 5.2

Example  17, 18 and Comparative example  13

Fine powder was prepared in the same manner as in Example 15, except that the solid paraffins were mixed together at the content ratios shown in Table 6 when the green coal and the semi-carbonized biomass were mixed in Example 15. At this time, the solid paraffin content means the content (%) in 100g of the fine powder.

Differential fuel Paraffin content
(%) Temperature rise
(℃) Spontaneous combustion
Prevention Example 17 Example 16 One 69 ○ Example 18 Example 16 2 65 ○ Comparative Example 13 Example 16 0.5 180 ×

In order to measure the effect of preventing spontaneous ignition according to the degree of coating of fine fuel, the coated fine raw materials obtained in Examples 17, 18 and Comparative Example 13 were stored in a ton bag at a weight of about 300 kg and the storage form was compared with air in the air. To infer the degree of reaction, they were stored in closed, normal (medium between sealed and open) and open types, respectively. In order to observe the temperature change during storage, a thermocouple (high temperature measuring device) was installed to continuously observe the temperature change over time (see FIGS. 2 to 4).

That is, Figure 2 is a graph showing the temperature change during storage of the fine powder coated with 0.5% paraffin obtained in Comparative Example 13. In the graph of FIG. 2, the differential fuel temperature at the beginning of the ton bag storage immediately after pulverization showed a temperature of about 30 to 40 ° C., and showed a steep temperature change on the third day (above 100 ° C.). Apparently there was no change with temperature rise. On the 4th day, the ash bag started to smoke at a temperature of about 160 ° C or higher, and the ash burned at the local area where smoke continued continuously inside the tone bag was visually confirmed. Therefore, the prevention of spontaneous ignition of the fine fuel coated with 0.5% of the solid paraffin obtained in Comparative Example 13 was found to be ineffective.

Figure 3 is a graph showing the temperature change during storage of the fine fuel coated with 1% paraffin obtained in Example 17. At this time, the grinding, coating storage conditions were performed in the same manner as the test conditions of 0.5%. Unlike FIG. 2, the initial storage temperature was about 60 ° C., which is relatively high. It showed a temperature rise curve for about 1 day, but since then, the temperature tended to decrease, and the effect of preventing spontaneous ignition was shown to be effective by decreasing the temperature of the stored fine fuel to room temperature. The maximum elevated temperature was found to be about 70 ° C or less.

Figure 4 is a graph showing the temperature change during storage of the fine fuel coated with 2% paraffin obtained in Example 18. The spontaneous ignition temperature change of the coated fine powder applied with 2% of solid paraffin did not show a big difference from the fine fuel mixed with 1%, and the maximum temperature was about 65 ℃. In addition, it was confirmed that the effect of preventing spontaneous combustion by showing the temperature drop curve within 24 hours.

2-4 As shown in FIG. 3, the maximum temperature rise was about 69 ° C. when 20% of volatile green coal was coated with paraffin 1%. In the case of coating with paraffin 1%, the maximum elevated temperature was similar to about 70 ° C. or less regardless of the type of sealing or opening and storing. In the case of 1% paraffin-coated pulverized coal, the temperature rising reaction was shown up to about 70 ° C., but the temperature was not raised to the temperature at which the ignition reaction was started, and the spontaneous ignition prevention effect was observed. However, in the green coal test coated with 0.5% paraffin, the maximum temperature was raised to about 180 ° C (3.5 days), and spontaneous ignition started from the green coal in the normal storage form under these conditions. The 0.5% paraffin coating test showed no spontaneous ignition inhibiting effect by the fine coating. This can be judged to provide a cause of ignition by having a continuous temperature increase effect at the uncoated topical area during raw material storage.

Claims (16)

80 to 90% by weight of green coal having 1% by weight or less of water, 3 to 20% by weight of volatile matter, 15% by weight or less of ash, 70 to 85% by weight of fixed carbon, and 0.5% by weight of sulfur,
A fine fuel comprising 10 to 20% by weight of semi-carbonized biomass. The method according to claim 1,
The calorific value of the fine fuel is 7,000 Kcal / kg Differentiated fuel characterized by the above. The method according to claim 1,
The green coal is not more than 15% by weight of moisture received;
It has a calorific value of more than 6,000 Kcal / kg on anhydrous basis.
A fine fuel comprising a bituminous coal containing 35 to 40% by weight of volatile matter, 10% by weight or less of ash, and 0.5% by weight or less of sulfur. The method according to claim 1,
The biomass is fine fuel, characterized in that any one of wood-based biomass or combustible household waste. The method according to claim 1,
The fine fuel is 7 to 10% by weight of fine powder having a particle size of 100 to 200 mesh,
Fine fuel comprising the fine powder 90 to 93% by weight having a particle size of 200 mesh or less. The method according to claim 1,
The fine fuel is fine fuel characterized in that the surface treatment using a surface coating material. The method of claim 6,
The surface coating material is a fine fuel, characterized in that the paraffin or stearic acid. The method of claim 6,
The surface coating material is a fine fuel, characterized in that used in 1 to 2% by weight relative to the total weight of the fine fuel. Drying the mined raw coal;
Manufacturing green coal through indirect heating and pyrolysis of the raw coal at 500 to 800 ° C. under an air-blocking sealed condition;
Injecting the biomass raw material into a closed, high temperature drying furnace and pyrolyzing to produce a semi-carbonized biomass;
Mixing the green coal and the semi-carbonized biomass; And
And finely grinding the mixed green coal and semi-carbonized biomass to produce a fine fuel according to claim 1. The method according to claim 9,
The raw coal is a 15% by weight or less moisture, anhydrous reference calorific value 6000 Kcal or more, volatile matter 35 to 40% by weight, ash content 10% by weight or less, sulfur content 0.5% by weight or less, the method for producing fine fuel. The method according to claim 9,
The method further comprises the step of cooling the green coal after the green coal manufacturing step, before being discharged to the outside. The method according to claim 9,
The mixing ratio of the green coal and the semi-carbonized biomass is 80 to 90% by weight: 10 to 20% by weight of the production method of fine fuel. The method according to claim 9,
The fine fuel is 7 to 10% by weight of fine powder having a particle size of 100 to 200 mesh,
A method for producing fine fuel, characterized in that consisting of 90 to 93% by weight of fine powder having a particle size of 200 mesh or less. The method according to claim 9,
The method further comprises incorporating a surface coating upon mixing green coal and semi-carbonized biomass; And
And finely grinding the green coal, the semi-carbonized biomass and the surface coating material together to surface-treat the fine fuel with the surface coating material. The method according to claim 14,
The surface coating material is a method for producing fine fuel, characterized in that paraffin or stearic acid. The method according to claim 14,
The surface coating material is a method for producing fine fuel, characterized in that used in 1 to 2% by weight relative to the total weight of the fine fuel.

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