JPH0352994A - Production of molded fuel - Google Patents

Abstract

PURPOSE:To improve water resistance of molded fuel without requiring heating by blending sulfur containing coal powder with fibrous biomass powder and slaked lime to give a mixture, molding the mixture under high pressure and treating the surface. CONSTITUTION:(A) 100 pts.wt. coal powder containing >=1.0wt.% combustible sulfur (anhydrous base) is blended with (B) 15-45 pts.wt. fibrous biomass powder such as woody waste, bagasse or strained lees of cotton seed oil having 2-3mm particle diameter and (C) slaked lime. The mixture is molded under 2,000-5,000 kgf/cm<2> high pressure into a briquette state and the prepared granulated material is subjected to surface treatment with a solution of paraffin and heavy oil A having weight ratio of paraffin and heavy oil A=(1:9)-(5:5) to give the objective molded material.

Description

[Detailed description of the invention]

[Industrial Field of Application J The present invention uses coal powder containing high chlorous content as the main raw material,
to this! This invention relates to a method for producing molded fuel, which is characterized by imparting water resistance through surface treatment to high-pressure granules containing woven fibrous biomass powder as +1 raw material and slaked lime as a desulfurizing agent.

[Conventional technology]

Regarding the molded fuel in which low sulfur content coal powder is used as the main raw material and wood powder, which is a type of biomass, is used as an auxiliary raw material, and the blending ratio of coal and biomass raw materials is within the range required by 1I of the present invention, the present inventors et al. It is publicly known due to two inventions +11121 by. One method is to set the raw material composition ratio (weight) of coal, wood, and wood waste from 9:1 to 5:5, and for example, at a temperature of 20
This is a molded fuel obtained at 0°C and a pressure of 300 kg/a1. Another feature is to impart binder activity to the wood components in the mixture by holding the above-mentioned coal/wood powder mixture in the coexistence of water vapor at a temperature range of 80 to 100°C for a certain period of time. This is a method for producing molded fuel. The coal/wood molded fuel returned in this way has the following characteristics compared to just coal.
<L) The amount of smoke generated during f1m firing is extremely small. (
2) Good shape retention during combustion. (3) Low ash content. (4) Good ignitability. (5) Since powdered raw material is used, it can be molded into any shape and size to match the side of the combustion equipment or combustion machine. (6) It is inexpensive because it does not use a binder. (7) It saves resources because it uses wood waste. [Problems to be solved by the invention] The coal/wood molded fuel obtained by the conventional technology has the above-mentioned characteristics. However, unless further improvements are made in the following points, it is difficult to accept coal/wood molded fuel as an alternative energy to petroleum in terms of economy and quality given the current petroleum energy situation.In other words, main raw materials The quality of coal is subject to a wide range of targets, for example, it can be used even if it has a high sulfur content.■ The auxiliary raw material, fiber biomass, is not limited to wood waste, and various types can be used. ■For energy saving purposes, it can be molded without heating.■The molded fuel has water resistance, etc.

[Means for solving the problem] As a result of various studies to improve the above-mentioned points, we have developed a book as described in the claims by using a roll press method that is highly mass-producible and can be granulated under high pressure. This led to the invention. The manufacturing method according to the present invention will be explained below. The manufacturing process according to the present invention includes raw material preparation (1), mixing (I1),
It is roughly divided into the following steps: molding (Ill), deburring (+V) of the molded product, and surface treatment (V). Raw material adjustment 1m (
In 1), the main raw material, coal, is dried to its own moisture content and crushed to a particle size of 2 to 3 grains or less. Regarding biomass, in addition to wood waste materials such as sawdust and bark, we also target bagasse (sugar cane lees), beet pulp, rice hulls, and wheat straw, which are dried to a moisture content of 10% or less and made into grains. Grind to a diameter of 2 to 3 ms+ or less. Mixing process (
In II), using raw materials whose particle size and moisture content have been adjusted in the above steps, 15 to 45 parts by weight of fiber-containing biomass powder is added to 1001 m parts of coal powder, and 100 to 150% of the combustible sulfur content of the coal is added. Add an equivalent weight of slaked lime and stir to mix uniformly. In the present invention, the combustible sulfur content is l. Owt% or more coal is the target, and molded fuel using less than that amount of coal contains biomass with an extremely low sulfur content, so there is no practical problem in terms of the generation of sulfur oxides. In the forming process (Ill), the mixture is continuously granulated into briquettes through a feeder by a roll press under a pressure of 2,000 to 5,000 kgf/cm'' without heating, and then granulated into briquettes. The process (I
The additional grains from which pari has been removed through the screen of V) are supplied to the surface treatment process $1 (V). Meanwhile, the paris are passed through the feeder again and formed by a roll press. In the surface treatment step (V), the obtained granules are crushed for several seconds in a solution having a weight ratio of paraffin = heavy oil A = l:9 to 5:5, and the above solution layer is formed on the surface of the granules. Form. Hereinafter, the present invention will be explained in detail with reference to Examples. [Example] The fuel used in the example was low-grade lignite as coal, wood waste wood, bagasse as NI#I biomass,
They are wheat straw, cottonseed oil press lees, and rice hulls. These raw materials were pulverized to 2 μm or less each, mixed to a predetermined raw material composition ratio, and mixed thoroughly with stirring without heating. Next, 15 kg of these mixtures were fed to a roll press using a screw feeder and molded under the conditions shown in Table 1. This operation was repeated five times for each mixed sample to continuously mold a total of 75 kg of raw material, and the pars of the granules were removed through a LESM sieve. Subsequently, the obtained granules were mixed with 10% paraffin and 90% heavy oil A (weight ratio).
The sample was soaked in a solution consisting of for about 3 seconds and then left at room temperature. Table 2 shows the fracture strength of the granules thus obtained. As is clear from this table, the strength of the molded product differs depending on the type of biomass, but any biomass can be made by high-pressure roll press without using any special binder and without heating. It was possible to produce coal/biomass-based molded fuel. Table 2 shows biomass 20
Although only an example of wt% blending is shown, it goes without saying that the strength of the granules increases as the amount of biomass blended increases. Table 3 shows the analysis values of grains using wood waste and bagasse as examples of raw coal and biomass, and also shows a comparison of the effects of desulfurization agents. Raw coal is a low-grade coal with an extremely high sulfur content, containing a large amount of pyrite-like substances that have a low thermal decomposition temperature, and cannot be used as is because it generates large amounts of sulfur oxides when used as fuel.
However, by blending biomass and slaked lime, the amount of sulfur oxides generated was significantly reduced compared to raw lignite coal. This has also been confirmed by measuring the amount of non-combustible sulfur contained in combustion ash after combustion in an actual coal stove. Therefore, the combustible sulfur contained in coal reacts with slaked lime during combustion. 8il, it is nothing but fixed in the ash in the form of anhydrite. In addition, it goes without saying that this granule has the same combustion characteristics as the well-known coal-wood molded fuel mentioned above, and in terms of the effect of the desulfurization agent, the comparison between granules I1 and ① in Table 3. As is clear from the above, slaked lime has a greater desulfurization effect than calcium carbonate. This is due to the difference in thermal decomposition temperature between the two, and in the case of the shaped fuel according to the present invention,
Slaked lime is more suitable as a desulfurizing agent. In addition, quicklime is used as a desulfurizing agent for calcium compounds, but if it is present in molded products as it is, it has the disadvantage of reducing its strength, so measures are taken to ensure that the final product is Ca(OH)a. There must be. Therefore, the reason why slaked lime is used in the present invention is as mentioned above. Regarding the water resistance of the granules, the amount of precipitation 50% was determined by spraying.
mm/h for 120 minutes, the results showed that untreated granules immediately became wet and disintegrated;
The surface-treated sulfur-forming product showed no change in shape even after 120 minutes of precipitation, and its water absorption amount was 1. Although it was small at around 0 wt%, a significant improvement in water resistance was observed. Therefore, the molded fuel according to the present invention can sufficiently withstand exposure to water due to temporary rain during normal outdoor storage and transportation, and also has a small amount of water absorption at that time, so even if it is exposed to water, It can be used as fuel without drying. The use of paraffin as a surface treatment agent to impart water resistance to conventional molded fuels is well known.
However, paraffin is an expensive raw material, and it is desirable to keep its usage to a small amount from the viewpoint of cost. The present invention was made based on the results of various studies aimed at replacing expensive paraffin with inexpensive paraffin as much as possible, and at the same time imparting the same level of water resistance as paraffin alone. In other words, as shown in the example, sufficient water resistance can be achieved even when 90% of paraffin is replaced with inexpensive Alk oil, and when this mixed solution is used, the A heavy oil component mainly flows into the inside of the molded fuel. One paraffin component remains on the surface, resulting in a surface condition similar to when paraffin alone is used. Therefore, the use of paraffin and heavy oil solutions as surface treatment agents in the present invention is based on the above findings. [Effects of the Invention J] As explained above about the present invention, the present method for producing shaped fuel uses high sulfur content coal and various biomass as raw materials.
In addition to having excellent combustion characteristics similar to well-known coal and wood waste molded fuels, it is possible to mix and process raw materials during the manufacturing process.
Its main feature is that it does not require heating during molding and is water resistant. Therefore, the present invention provides a molded fuel that is excellent not only in terms of quality and combustion characteristics, but also in terms of economical cleanliness, diversity of factory locations, and ease of production, and it is possible to utilize unused energy resources. It not only promotes effective utilization but also makes a major contribution from the standpoint of resource conservation and energy conservation. Table 1 Molding conditions Table 2 Breaking strength of granules (kgf) Lignite (material), biomass 20, slaked lime 10% composition table 3 Analysis values of raw coal and granules A゛B ゜C ゜D゜Moisture (X) Ash content (χ) Volatile content (X) Fixed carbon (z) Total calorific value (kcal 8 wards) Total sulfur (sulfur, anhydride) Nonflammable sulfur (〃) Combustible sulfur (〃) l2.0 24.2 34. 2 29.2 4,410 6.8 0.5 6.3 6.5 39.8 36.4 17.3 4,250 4.2 3.7 0.5 6.3 40.2 37.O l6 .5 4 , 230 4.5 3.9 0.6 6.9 33.3 39.2 20.6 4,260 4.9 1.2 3.7 15%

Claims (1)

[Claims] 15 parts by weight of fibrous biomass powder per 100 parts by weight of coal powder containing combustible sulfur content of 1.0 wt% or more (anhydride group)
After high-pressure molding a mixture of ~45 parts by weight and an appropriate amount of slaked lime into a briquette shape, the resulting granules are surface-treated with a solution with a weight ratio of paraffin: heavy oil A: 1:9 to 5:5. A method for producing shaped fuel characterized by