JPS6164788A - Upgrading of low-grade coal - Google Patents

Abstract

PURPOSE:To enable the use of equipment having a built-in heating pipe, by producing a heating medium by the use, as fuel, of the gas generated in the carbonization of a low-grade coal, and carrying out the carbonization using this heating medium. CONSTITUTION:A low-grade coal A is treated in a drier 10 with a heating medium (a) obtained by burning coal (b) in a producer 20. The dried coal B thus obtained is treated in carbonization equipment 30 equipped with a built-in heating pipe 31 to form a carbonized coal C, which passes through cooling and adsorption equipment 40 and is taken out as a reformed coal D. Gases (c) such as those of tar and a resin are introduced into the cooling and adsorption equipment 40, where the tar component is adsorbed by the carbonized coal C to be removed. A refined gas (c') thus obtained is then fed into a heating- medium producer 21, and the heating medium (d) produced therein is introduced into the heating pipe 31 where it is used as the heat source for the carbonization equipment 30. The heating medium (d') discharged from equipment 30 is employed as a part of the heat source for the drier 10.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a method for improving the quality of low-rank coal.

[Background of the invention]

The fuel used for drying and carbonizing coal is coal.

It was common to use gas or oil. In the case of low-rank coal as used in the present invention, it is cheapest to use the low-rank coal itself as a fuel. However, when such coal is used as fuel, some of the ash in the coal is mixed into the hot air, and even if it is collected in a cyclone, some ash still remains in the hot air. When performing drying or carbonization, there is a concern that the heating tubes will be worn out due to the influence of this ash content.

In contrast to this method, Koppe 1man drying.

In the case of the carbonization process, the gas generated during heat treatment was used as fuel, and no external fuel was required.

However, since this method requires the generation of a considerable amount of gas, the carbonized coal becomes more coked than necessary, resulting in an excessively high fuel ratio, making it unsuitable as a fuel for conventional boilers. There were some problems.

[Purpose of the invention]

An object of the present invention is to provide a method for improving the quality of low-rank coal that can use a device equipped with a heating tube as a carbonization device.

[Summary of the invention]

The present invention is characterized in that a heating medium 1 is generated using gas generated from low-rank coal as fuel during carbonization treatment of low-rank coal, and at least carbonization treatment of low-rank coal is performed using the heating medium, and the low-rank coal contains no ash. By avoiding the need to carbonize low-grade coal using a heat medium that does not require a heat transfer agent, it is possible to use a built-in device such as a heating tube as a carbonization device.

[Embodiments of the invention]

As mentioned above, if a heating medium generated by burning coal is used as a heating medium for drying or carbonizing low-grade coal, there is a problem that the heating tubes will wear out due to the ash mixed in the heating medium. , Therefore, a device with a built-in heating tube in the carbonization device,
For example, it has been difficult to use a moving bed type carbonization apparatus.

On the other hand, in the case of low-grade coal, a considerable amount of gas is generated during carbonization, and although it is insufficient as a heating medium for the entire drying and carbonization process, it has been found that it is sufficient for carbonization purposes.

Therefore, if a heat medium generated using this gas as fuel is used for carbonization, and a heat medium generated using coal as fuel is used for drying, the above-mentioned influence of ash content on the heating tubes will be avoided. In some cases, a device 1 having a built-in heating tube, for example, a moving bed type carbonization device may be employed as the carbonization device.

An embodiment of the present invention will be described below with reference to the drawings.

In the drawing, low-grade coal A is supplied to a drying device jlO, such as a rotating drum dryer, where it is dried to become dry coal B. As the heating medium in this case, heating medium a generated in a heating medium generating furnace is mainly used. Coal coal is supplied as fuel to the heating medium generating furnace and is burned there to generate heating medium a. For example, dry charcoal B is delivered to a dry bag via a rotary feeder (not shown)! It is supplied from j10 to carbonization device t30, where it is carbonized to become carbonized coal C. Carbonization bag! (9
) is, for example, a device with a built-in heating tube 5, such as a moving bed type carbonization device. For example, the carbonized coal C is cooled and
Suction bag! 40, where it is cooled and subjected to tar adsorption treatment to become reformed coal and taken out of the system. The reformed coal taken out of the system is stored, for example, in a coal storage yard (not shown), and then burned in, for example, a power plant combustion boiler (not shown).

In the drawing, when dry coal B is carbonized in carbonization unit I, gas C such as tar and resin is generated from dry coal B, and this gas C is generated in carbonization unit i! (capital) and supplied to the cooling/adsorption bag WL40. The gas C supplied to the cooling/adsorption device is brought into contact with the carbonized coal C cooled by a refrigerant, such as cooling water, flowing through the cooling pipe 41, and as a result, the carbonized coal C contains the gas C. The tar is adsorbed. Gas C', from which most of the tar 1 has been removed, is taken out from the cooling/adsorption device and supplied as fuel to the heating medium generating furnace, where it is combusted to generate heating medium d. This heating medium d is supplied to the heating tube (2) of the carbonization device i30.

The dry charcoal B is heated and carbonized by the heating medium d flowing through the heating tube 31. After that, the heating medium d' is discharged from the heating tube 31, but since the heating medium d' is at a fairly high temperature, it is supplied to the drying device jlo and used as a part of the heating medium for drying. do.

As described above, since the drying device i10 employs a rotary drum dryer or the like to indirectly heat the low-grade coal A'1, there is no particular problem even if some ash is mixed in the heating medium.

In addition, in this case, as a heating medium for dry distillation treatment of dry coal B,
Since the heating medium d generated using the gas C' as fuel is used, there is no concern that ash will be mixed into the heating medium, and for example, a moving bed type carbonization apparatus can be used without any problem.

〔Example〕

A test was conducted using subbituminous coal from the western United States having the properties shown in Table 1. The drying temperature was set at 150°C, and the carbonization temperature was set at 350°C. As a result, the amount of low hydrocarbon gas generated was 37N.
The calorific value of one raw coal is 5゜700 kcal/kg
Then, it was supplied to a heating medium generating furnace for carbonization.

The generated heat medium is cooled by mixing air and sent to the carbonization equipment 72
Feed at 5°C and discharge at 410°C. As a result of (2), the properties of the produced reformed coal were such that it could be fully used as fuel coal for boilers, as shown in Table 2.

In addition, in addition to this embodiment, the gas generated from dry coal by carbonization treatment may be directly supplied as fuel to a heating medium generation furnace for soft tubes to generate a heating medium for carbonization.

〔Effect of the invention〕

As explained above, the present invention generates a heating medium using gas generated from low-rank coal as fuel during carbonization treatment of low-rank coal, and carbonizes the low-rank coal with the heating medium to remove ash content. Low-grade coal can be carbonized using a heat medium that does not require
This has the advantage that a device having a built-in heating tube can be used as the carbonization device.

[Brief explanation of drawings]

The drawing is a flowchart of an apparatus for converting low-rank coal into high-grade coal according to the present invention. common

Claims (1)

[Claims] 1. In a method of at least carbonizing low-rank coal to improve its quality, a heating medium is generated using gas generated from the low-rank coal during the carbonization treatment of the low-rank coal as fuel, and the heating medium is used to improve the quality of the low-rank coal. A method for improving the quality of low-rank coal, characterized by subjecting it to at least carbonization treatment.