JPS58142987A - Dehydration of brown coal with steam - Google Patents

Abstract

PURPOSE:To improve the efficiency of the dehydration of brown coal, by sealing brown coal in plural pressure containers, feeding super heated steam to the first pressure container so that the brown coal is dehydrated and dried, transferring saturated steam to the second pressure container so that the brown coal is dehydrated with the saturated steam. CONSTITUTION:The brown coal 3 is sealed and hermetically closed in plural pressure containers, the first pressure container 1 and the second pressure container 2 such as autoclave. Superheated steam is fed to the first pressure container 1, passed through the brown coal 3, so that the brown coal 3 is dehydrated and dried, and saturated steam or steam near to the saturated steam is exhausted. The saturated steam or the steam near to it is fed to the second pressure container 2 or pressure containers following it, and the brown coal 3 is dehydrated with the saturated steam. Preferably the first pressure container 1 is charged with fine brown coal and the second pressure container 2 with coarse brown coal.

Description

[Detailed Description of the Invention] The present invention is applicable to brown coal, lignite, sub-bituminous coal, etc., which have a low degree of coalification.
This invention relates to a method for steam dehydration of organic solid materials such as high moisture coals.

Drying of organic solid materials is generally carried out by evaporation method, which involves heating the material to be dried. It is not suitable for dehydrating and drying lignite because it evaporates and consumes a lot of heat, and if the dehydrated product is rice flour, there are problems such as single dust, spontaneous combustion, and explosions.

Conventionally, brown coal contains a large amount of water in its fiber structure or capillary tubes, and in this method, the brown coal is sealed in a pressure vessel such as an autoclave, and hot water or saturated steam is supplied at high temperature and pressure.1. 1. without evaporating most of the water it contains. The fly-stewing method is already known, which allows dehydration and drying without the need for latent heat by expanding the volume of water and contracting the volume of brown coal.

1, or 1. Therefore, in the dehydration method in which lignite is heated with hot water, in order to extract the dehydrated lignite from hot water at high temperature and high pressure, it must be depressurized and cooled - at this time some of the water turns into lignite. Because it is reabsorbed, the effect of dehydration is reduced.

Also in the saturated steam dehydration method.

If the produced water, which consists of liquid water separated from lignite or condensed water of steam, is separated, and the lignite is in saturated steam, then the pressure is reduced, there will be no re-absorption of moisture.1-1 Remaining moisture Evaporation 1. The effect will be even higher as it will be reduced by
When the grain size of lignite is small, the separation of lignite and produced water is insufficient, and the produced water trapped between grains reabsorbs moisture, making it difficult to dehydrate and dehydrate it sufficiently.
The disadvantage is that it cannot be dried.

The present invention has been made in view of the above-mentioned points, and consists of: sealing lignite in a plurality of pressure vessels (17); supplying superheated steam to the first pressure vessel; (1) supplying superheated steam to the first pressure vessel; 1. Dehydrate and dry the lignite and discharge saturated or nearly saturated steam. eye.

This saturated steam or nearly saturated steam is then supplied to the second pressure vessel or subsequent pressure vessels! By saturated steam dehydration of lignite in step 2, the advantages of the conventional saturated steam dehydration method can be utilized [and, by combining it with the evaporative drying method, it is also possible to process fine lignite.1. The purpose of this invention is to provide a method for steam dehydration of brown coal.

The configuration of the present invention will be explained below with reference to the drawings.

FIG. 1 shows an embodiment of the lignite steam dehydration method of the present invention, in which LABa 1 is a first pressure vessel such as an autoclave; A2 is a second pressure vessel such as an autoclave; Closed and closed. First, superheated steam is supplied to the first pressure vessel 1, and is passed through the brown coal 6 to dehydrate and dry the lignite.7 The steam discharged from the first pressure vessel 1 is saturated steam, but still nearly saturated steam. This steam is then supplied to the second pressure vessel 2 to dehydrate the lignite 6 with saturated steam. The produced water discharged from the second pressure vessel 2 is used for brown coal power preheating. In Figure 1, the pressure vessel is 2
Although only one pressure vessel is shown in the figure, there may be three or more pressure vessels.

In the method shown in FIG.
Even if the water contains fine particles, the water will evaporate and become a gas.
Since the water is removed in step 7, the amount of dehydration will not be reduced due to moisture being trapped between particles. Also, the supplied superheated steam and steam evaporated from lignite are monosaturated steam [7] and used in the second pressure vessel 2. and then further used as part of the produced water to preheat another brown coal.

Since the water is discharged as water at around 100°C, the heat consumption is almost the same as in the saturated steam dehydration method.

Further, as shown in FIG. 2, the first pressure vessel 1 may be filled with fine lignite 4 and the second pressure vessel 2 may be filled with coarse lignite 5. In this case, the superheated steam heats only the fine brown coal 4.
The advantage is that only a small amount of superheated steam is consumed, since the moisture can be evaporated using only 5 steps.

FIG. 3 shows another embodiment of the method of the invention.1. I'm here.

In this method, the brown coal 3 in the first pressure vessel 1 is dehydrated with saturated steam [7], then superheated steam is supplied [1], the brown coal 6 is dehydrated and dried, the saturated steam is discharged 1°, and then the brown coal 6 is dehydrated and dried. This saturated steam is supplied to the second pressure vessel 2 or subsequent pressure vessels (not shown).1. After the lignite 3 is dehydrated with saturated steam, superheated steam is supplied.1. The lignite 3 is dehydrated and dried. in this case.

Since a considerable portion of the moisture in the brown coal 3 is removed in liquid form, the superheated steam only needs to mainly evaporate intergranular water, resulting in less heat consumption.

Further, as shown in FIG. 4, it is possible to seal coarse lignite 5 in the bottom of the pressure vessel and fine lignite 4 in the upper part. In this case, there is an advantage that less water is bound to the lignite during the saturated steam dehydration process, so the consumption of superheated steam is reduced, and less fine lignite is washed away by the produced water during the saturated steam dehydration process. be.

FIG. 5 shows a case where saturated steam partially discharged from one pressure vessel 1 is supplied to a plurality of (two as an example in FIG. 5) pressure vessels. That is, saturated steam is supplied to the second pressure vessel 2, the third pressure vessel 6, etc. As shown in FIG. 6, fine brown coal 4 is contained in the first pressure vessel 1, and coarse brown I# is contained in the second pressure vessel 2, third pressure vessel 6, etc.
5 may be encapsulated. The smaller the particle size, the more the amount of water restricted between grains.
Anything less than m becomes a problem. The particle size distribution of lignite varies depending on the quality of the coal (hardness, friability), mining method, etc., but it is usually 115. At most 1/3 of the amount of fine particles becomes a problem. Therefore, it is possible to carry out the process more effectively by providing about 2 to 4 pressure vessels for treating coarse lignite for each pressure vessel for treating fine lignite. Fifth
In the method shown in Figures and Figure 6, the first pressure vessel 1
The brown coal inside.

Drying with superheated steam alone may be carried out, or saturated steam dehydration may be carried out.
, then dry with superheated steam 1. However, there are design issues, such as heat balance and particle size balance, when the superheated steam required for fine lignite is less.

A method of drying using only superheated steam is convenient, and
When the saturated steam discharged from pressure vessel 1 is greater than the saturated steam required for the pressure vessel for dehydrating coarse lignite, part 1
It is convenient to first dehydrate the fine lignite in the pressure vessel 1 with saturated steam.

In addition, in the methods shown in Figures 1 to 6, if the required amount of superheated steam is very small, only a part of the saturated steam used for saturated steam dehydration is discharged from the pressure vessel in which superheated steam drying is performed. It is a thing.

The remaining saturated steam is supplied from an external steam source.

As explained above, the method of the present invention effectively combines the advantages of the conventional saturated steam dehydration method with the evaporative drying method using superheated steam, and can be used not only for lumps and coarse grains of lignite. , it has the effect of being able to efficiently dehydrate even fine-grained lignite.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing one embodiment of the brown coal steam dehydration method of the present invention, and FIGS. 2 to 6 are explanatory diagrams showing other embodiments of the method of the present invention. 1...First pressure vessel, 2...Second pressure vessel, T...
Lignite-4...Fine-grained lignite, 5...Coarse-grained lignite, 6...Continued from page 1 of 3rd pressure vessel 0 Inventor: Kawasaki, 3-1 Higashiyosaki-cho, Chuo-ku, Kobe City 0 inventions at the Kobe Plant of Heavy Industries, Ltd. Author: Kei Komai - 3-1-1 Higashiyosaki-cho, Chuo-ku, Kobe 0 inventions at the Kobe Plant, Kawasaki Heavy Industries, Ltd. Author: Takeshi Wakabayashi 3-chome, Higashiyosaki-cho, Chuo-ku, Kobe City No. 1 No. 1 Kawasaki Heavy Industries Co., Ltd. Kobe Factory ■Applicant Kawasaki Heavy Industries Co., Ltd. 3-1-1 Higashi Kawasaki-cho, Chuo-ku, Kobe City

Claims (1)

[Claims] 1. Enclose brown coal in a plurality of pressure vessels, supply superheated steam to the first pressure vessel 12 to dehydrate and dry the brown coal,
Discharging saturated or nearly saturated steam and then supplying this saturated or nearly saturated steam to a second or subsequent pressure vessel.1. A method for steam dehydration of lignite, which is characterized by dehydrating lignite using saturated steam. 2. The method for steam dehydration of brown coal according to claim 1, wherein fine brown coal is sealed in the first pressure vessel and coarse brown coal is sealed in the second pressure vessel. 6 Enclose lignite in multiple pressure vessels, dehydrate the lignite in the first pressure vessel with saturated steam, and then supply superheated steam to dehydrate and dry the lignite, and discharge saturated or nearly saturated steam. First, this saturated steam or nearly saturated steam is supplied to the second pressure vessel or subsequent pressure vessels to dehydrate the brown coal with saturated steam, and then superheated steam is supplied to dehydrate and dry the brown coal. A method for steam dehydration of lignite, which is characterized by: 4. The method for steam dehydration of lignite according to claim 3, wherein coarse lignite is sealed in the bottom of the pressure vessel and fine lignite is sealed in the upper part. 5. Claim 1, in which only a part of the saturated steam used for saturated steam dehydration is discharged from the pressure vessel in which superheated steam drying is performed, and the remaining saturated steam is supplied from an external steam generation source. , the method for steam dehydration of lignite according to item 2, $3 or 4.