JP2005194341A - Method for molding coal powder or mixture of coal powder and another substance - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a molded material having strengths by low compressive force from coal from which a molded material having strengths is not obtained when coal powder or coal powder mixed with another substance is compression molded. <P>SOLUTION: The method for molding a mixture comprises mixing coal powder having ≤10% or ≥30% volatile matter content, which has a large amount of expansion and does not give a molded material having strengths, with coal powder having >10% and <30% volatile matter content, which has a small amount of expansion and gives a molded material having strengths in the weight ratio of ≥15% and compression molding the mixture by using a roll type molding machine at ≥35 kN/cm pressure between rolls and ≤ 60 kN/cm compression force when coal powder is compression molded or coal powder is mixed with vegetable powder such as saw dust, maize stem, slaked lime as a desulfurizing agent, or the like, so as to reduce soot and SOx in flue gas during combustion and to make briquette. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to molding of coal powder or a mixture of coal powder and other substances such as wood flour.

  Coal powder of about 3 mm or less, or plant material such as pulverized wood, corn stalk, cocoon or the like of about 2 mm or less mixed with coal powder at a weight ratio of 5 to 30% and slaked lime at a weight ratio of about 2 to 10% A compact briquette having a size of about 3 cc or more is formed by compression molding to improve combustibility or to make transportation and storage convenient. In addition, it is compression-molded into a plate shape having a thickness of 10 mm or less, and pulverized into granules of about 10 mm or less to obtain industrial raw materials. To form a briquette or plate, a roll type molding machine that supplies powder raw material between two rotating rolls, or a press mold that fills the powder raw material in a cylindrical cylinder and compresses it with a piston. A molding machine is used.

  However, depending on the type of coal, in order to make a molded product with a strength that does not break during transportation and storage, the press molder has a compressive force exceeding 350 MPa. A high compressive force of 75 kN / cm or more between the rolls is applied, or a binder such as starch, molasses, and a polymer agent is mixed with the raw material in a weight ratio of about 2% to 10%. Increasing the compression force or mixing a large amount of binder increases the molding cost.

The problem to be solved is that when a coal powder or a mixture of coal powder with other substances is compressed to make a molded product, a binder is mixed or the molding pressure is increased depending on the type of coal. This is the point that must be done.

Means to solve the problem

  The present invention clarifies the relationship between the volatile content of coal and the strength of the molded product for coal with different volatile content when compression molding of coal powder or a mixture of coal powder and other materials such as wood powder. , Volatile coal powder that gives a strong molded product by compression is mixed with volatile coal powder that does not give a strong molded product, and strong molding with low compressive force without mixing binder A product can be obtained, or a strong molded product can be obtained with a low compressive force even if the amount of the binder is reduced.

Comparing the height of the molded product when coal powder is filled into a cylindrical cylinder with a press molder and compressed with a piston, and the height of the molded product after taking out the molded product from the cylinder after compression molding The molded product expands after removing the compressive force. In a roll molding machine, the molded briquette expands immediately after leaving the roll. The amount of expansion differs when the volatile content of one of the coal components is different. Coal with a volatile content of more than 10% and less than 30% has a small amount of expansion of the molding formed by the press molding machine, and the molding has a high crushing strength. Briquettes formed with a roll inter-roll pressure of 30 kN / cm or more and 60 kN / cm or less per roll unit width divided by the width of the outer peripheral surface can obtain a crushing strength that can withstand impact during transportation and storage. Coal with a volatile content of 10% or less and 30% or more has a large amount of expansion and has a low crushing strength. Coal powder with a large amount of expansion causes the particles to expand after compression molding, weakens the adhesion between the particles, reduces the bonding force, and lowers the strength of the molded product.

  The amount of expansion is low and the strength of the molded product is weak. If a binder is not mixed, a strong molded product cannot be produced. The volatile matter that increases the strength of more than 10%, coal powder of less than 30% is continuously embedded between the particles, mixing at 15% or more by weight ratio that produces the effect of increasing the strength of the molded product, By using a roll-type molding machine and compressing with a compression force between rolls of 35 kN / cm or more and 60 kN / cm or less, a strong briquette that can withstand transportation and storage can be obtained without mixing the binder. Even when the agent is mixed, the amount of the binder can be reduced.

  In addition, coal powder moldability is good even when briquettes are made by mixing vegetable powder such as wood chips and corn stalk and desulfurizing agent such as slaked lime to reduce soot and SOx in the flue gas during combustion. Due to the impact of briquette crushing strength, coal powder with a large volatile content of 10% or less and 30% or more has low molding strength and may require a binder, but the volatile content is 10%. More than 15% coal powder with a volatile content of 10% or less and 30% or more is mixed with coal powder with a weight ratio of 15% or more, and the inter-roll pressure is 35 kN / cm or more and 60 kN / cm or less with a roll molding machine. By compressing with the compression force, briquettes with strength that can withstand transportation and storage can be obtained without mixing the binder, and even when the binder is mixed, the amount of binder can be reduced. It can be reduced.

The invention's effect

  When coal powder or coal powder is mixed with wood, molded, and used as fuel or industrial raw material, the volatile matter with a large amount of expansion of the molded product such as briquette after molding is 30% or more, 10% Mix the following coal powder with a volatile content of less than 10% and a weight ratio of 15% or more in which the coal powder of less than 30% is continuously embedded between the particles of the molded product and produces an effect. By molding, a strong molded product can be obtained even with a low compressive force, and even when it is necessary to mix a binder, the amount of the binder can be reduced. In the case of molding with a roll-type molding machine, a molded product that can withstand transportation and storage can be produced by a compressive force between rolls of 35 kN / cm or more and 60 kN / cm or less.

  When compressing and molding coal powder or coal powder mixed with other materials such as wood powder, if the coal powder has a volatile content of 10% or less, 30% or more and a strong molded product cannot be obtained, 15% or more of coal powder with a volatile content exceeding 10% and less than 30% can be obtained in order to obtain a strong molded product, and compression between rolls between 35 kN / cm and 60 kN / cm with a roll molding machine By compressing with force, it was possible to make a strong molded product.

  A cylinder with a diameter of 25 mm is filled with coal powder with a different volatile content at a certain height and compressed with a piston to make a tablet of the molded product. The tablet thickness after removing the compression force and the tablet thickness at the time of molding Ratio of tablet height after removing compressive force, ie {(tablet thickness after removing compressive force-tablet thickness when compressed) / tablet after removing compressive force The thickness of the molded article is set to 100%, and the expansion rate of the molded product and the crushing strength at the time of breaking the molded product are measured. The crushing strength of briquettes formed by a roll type molding machine having an inter-roll pressure of 25 kN / cm, 35 kN / cm, 60 kN / cm, and 75 kN / cm divided by the width of the outer peripheral surface of the roll that compresses was measured.

  Table 1 shows the results. Brittlet made with a roll-type molding machine, with a volatile content of more than 10% and less than 30% of 14% and 28% coal compression-molded tabrents with a low expansion rate and a tablet crushing strength of 15 kg or more. The crushing strength was 20 kg or more when the inter-roll pressure was 35 kN / cm, and it was strong enough to withstand transportation and storage. When the inter-roll pressure was 60 kN / cm, the crushing strength of the briquette was 35 kg or more. 8%, 35%, and 42% coal, which has a volatile content of 10% or less and 30% or more, has a large expansion rate of compression-molded tablets, and the crushing strength of tablets is 10kg or less. The crushing strength of the briquette is 20 kg or less even at an inter-roll pressure of 60 kN / cm, which is a weak briquette. It was strong enough to break during transportation and storage.

Coal with a volatile content exceeding 10% and less than 30% and having a small expansion rate has a significantly higher crushing strength for briquettes at 35 kN / cm than for briquettes having a roll-to-roll pressure of 25 kN / cm. In the process in which the powder is compressed between the rolls, as the compressive force increases, the gap between the particles narrows, and further, some of the particles break up to fill the gaps between the particles, increasing the density between the particles. There is a phenomenon in which the binding force becomes significantly stronger. From about 35 kN / cm between the rolls, some particles are crushed, the density is increased, and the briquette crushing strength is increased.
Coal with a volatile content of 10% or less, or 30% or more and a large expansion coefficient, when compressed, the particles are elastically deformed little, and the particles do not collapse. This weakens the bonding force between the particles.

  15% or more by weight of coal with good moldability with a volatile content of more than 10% and less than 30% is mixed with coal powder with a volatile content of 30% or more and poor moldability. A briquette with a high crushing strength was obtained.

  Table 2 shows the results. When coal powder with a volatile content of 30% or more with poor moldability is mixed with coal powder with a volatile content of more than 10% and less than 30% with a good moldability of 15% or more by weight, the inter-roll pressure is 35 kN / cm. The briquette crushing strength molded at 60 kN / cm is 20 kg or more, and it can withstand transportation and storage. When coal powder with good moldability is mixed at a weight ratio of 10% or less, the increase in crushing strength is small. When the coal particles having good formability are almost continuously embedded between the briquette coal particles, the crushing strength of the briquettes is greatly increased. Increasing the mixing amount to 20% increases the crushing strength of the briquettes.

  5% slaked lime and 8% molasses were mixed as a binder with 8% volatile matter coal powder, which had a large amount of expansion during molding, and molded with a roll molding machine at an interroll pressure of 35 kN / cm. The crushing strength of brikent was 22 kg, but slaked lime was 2% by weight as a binder in a mixture of coal powder with 8% volatile content and 15% by weight coal powder with good moldability of 14% volatile content. The briquette formed by mixing 4% molasses with molasses and molding with a roll molding machine at an inter-roll pressure of 35 kN / cm was almost the same at 24 kg. In other words, the amount of binder can be reduced by mixing 15% or more of coal with good moldability exceeding 10% and less than 30% into coal of 10% or less with poor moldability. It was.

  Raw material obtained by mixing 10% by weight and 3% desulfurizing slaked lime with coal powder dried to 3mm or less and crushed to 1mm or less, and wood powder dried to 15% or less and crushed to 2mm or less. The crushing strengths of briquettes made with a roll molding machine at an inter-roll pressure of 35 kN / cm and 60 kN / cm were compared.

  Table 3 shows the results. Wood flour is a fiber, and the compression force between rolls is about 25 kN / cm due to elastic deformation. The briquette is expanded after removing the compression force, and its crushing strength is low. The crushing strength of briquettes increases due to the strong intertwining of quality wood flour. However, if the coal volatile content is 30% or more and 10% or less, the briquette crushing strength is less than 20kg in the range of 35kN / cm to 60kN / cm between rolls. In order to make the strength not to collapse, it is necessary to mix a binder with the raw material or further increase the inter-roll pressure. By mixing 15% or more by weight of coal powder with good moldability exceeding 10% and less than 30%, the briquette's crushing strength becomes 20kg or more, and it can withstand transportation and storage. The briquette was obtained.

  In the case of coal with a volatile content of 35%, the pressure between rolls is 60 kN / cm to achieve a briquette crushing strength of 20 kg or more, but the coal powder with a volatile content of 14% or 28% is 15% by weight. % Mixing, the crushing strength of the briquette is 20 kg or more even when the inter-roll pressure is 35 kN / cm. That is, by mixing 15% or more of coal powder with good moldability exceeding 10% and less than 30%, the pressure between rolls can be lowered, and the power consumption during molding can be reduced. .

  When making briquettes by mixing other substances with coal, coal volatile matter will exceed 10% and coal less than 30% should be mixed 15% or more because coal formability affects briquette strength. This has the effect of increasing the strength of the briquette.

  Coal has the largest reserve of fossil fuels and is widely used as an industrial raw material or fuel. Powdered coal of about 5 mm or less is often generated during mining and transportation, and is a massive briquette. Alternatively, it is used in the form of a plate, but the amount of binder is mixed even if a binder is not used or a binder is used by a method utilizing the characteristics of coal volatile matter. The ability to produce a molded product that can withstand transportation and storage with a low molding pressure with a low molding pressure has the great advantage of reducing production costs and has the potential for use.

Claims (2)

  When molding coal powder or coal powder mixed with other substances, if the volatile content of the coal powder is 10% or less, or 30% or more, the volatile content exceeds 10% and less than 30% A method in which 15% or more of the coal powder is mixed and molded.   The method of Claim 1 WHEREIN: The method of shape | molding with the roll pressure of a roll type molding machine being 35 kN / cm or more and 60 kN / cm or less.