JPS5838788A - Method and apparatus for gasification of coal - Google Patents

Abstract

PURPOSE:To obtain high-colorific methane gas at a low cost, by reacting steam with dust containing unburned carbon and existing in the exhaust gas generated by the partial combustion of coal, and reacting the produced hydrogen with carbon monoxide in the above exhaust gas. CONSTITUTION:Coal is subjected to partial combustion in the combustion furnace 10 to obtain exhaust gas which contains dust containing unburned carbon (hereinafter called as char) and carbon monoxide, and the char and the carbon monoxide are discharged through the pipe 14. The char is separated by the char collectors 20, 40 and sent to the water gas furnace 50. The char is made to react with steam in the water gas furnace 50 to obtain hydrogen, which is mixed with the above exhaust gas in the methanater 60, etc. and reacted with carbon monoxide in the exhaust gas to produce methane.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a coal gasification method and apparatus, and more particularly to a method and apparatus suitable for obtaining high calorific value gas based on a coal partial combustion method.

When coal is partially combusted, a gas containing carbon monoxide* (Co) as a main combustion component is obtained, so coal can be gasified based on this coal partial combustion method.

However, the calorific value of CO is 3020 KcaJ/N-, which is lower than that of other hydrocarbon gases.

For example, even meta-y (CH4) with 1 carbon number has 9520Kca
It has a calorific value of 1/Nm3, which is more than three times that of CO.

In particular, when air is used to partially burn coal, there is a problem that the combustion gas contains a large amount of N, resulting in a significantly low concentration of CO and a low calorific value.

(Usually around 600-1000 Kca//N@”).

The purpose of the present invention is to solve the problems of the prior art,
It is an object of the present invention to provide a coal gasification method and apparatus that can obtain gas with a high calorific value even when air is used when coal is partially combusted.

The present invention converts CO into CH4 by reacting 900 KH produced by partial combustion of coal, and uses soot dust (hereinafter referred to as char) containing unburned coal*Yk produced during partial combustion of coal as a source of H. ) is reacted with water vapor, and Hl produced by a water gasification reaction between carbon and water in the char is used.

The embodiments shown in the accompanying drawings will be described below.

FIG. 1 is a block diagram of a coal gasification apparatus according to an embodiment of the present invention. The figure shows a 10Fi coal combustion furnace (in this embodiment, a jet combustion furnace), and is provided with an air supply pipe 11, a coal supply pipe 12, an ash discharge pipe 13, and a combustion gas discharge pipe 14.

Reference numeral 20 denotes a first char collecting device (a cyclone in this embodiment), to which the pipe 14 is connected, and a soot and dust delivery pipe 21 and a treated gas discharge pipe 22 are provided. 30 is a heat exchanger for recovering thermal energy generated by partial combustion of coal. 40 is a second char collector, which collects soot and dust not collected by the first char collector, and further reduces the dust 1 in the product gas obtained in the subsequent process. .

This collection device 40F'i is connected to the heat exchanger 30 and the pipe 21 by pipes 31 and 41, respectively, and is further connected to the metane +-60, which will be described later, via a pipe 42. 5
0 is a water gasifier, which reacts unburned carbon in the char supplied from an introduction pipe 51 connected to pipes 21 and 41 with steam supplied from a steam introduction pipe 52 to produce CO and H7. It is for producing water gas containing. 53 is an ash outlet, and 54 is a water gas discharge pipe. 60 is a methanator which supplies CO from the pipe 42 and CO supplied from the pipe 54; The reaction produces methane. 61 is a product gas take-off pipe.

Next, the operation of the embodiment apparatus configured as described above and the chemical reactions within each apparatus will be explained.

In the combustion furnace 10, the coal is partially oxidized to 2G + 02
→CO is produced by the reaction of 2CO. At the same time, soot dust (char) containing unburned matter is generated. This CO and char are discharged through tube 14. The spouted bed is used because it makes the partial oxidation reaction uniform and has a great effect of preventing coal particles from coalescing. This char is separated by cyclones 20 and 40 and sent to a water gasifier SOK. In the water gasifier 50-c'h, C1H! o-+co
+H1, OyobiCo +H, 0→Co, +H, A gas containing H as the main component is generated by the reaction. This H2
reacts with CO in the methanator to form Go + 3H, →C
Methane is produced according to the reaction M, + 1(, O.

As mentioned above, the heat generation t (9520K) per N of methane
cal) riH, (3050Kc!a#) and Co(3
It is significantly higher than -020Kca (7). Further, H and O produced in the methanator are liquefied and separated when cooled. Therefore, the product gas taken out from the methanator becomes rich in methane, and its calorific value increases.

In addition, in the methanator, Co + 3H, → CH4+ H
, O as the reaction progresses, a large amount of Hl is consumed. Therefore, it is preferable that the H2 concentration of the water gas taken out from the water gasifier 50 is as high as possible.

FIG. 2 shows a shift converter 55 installed between the water gasifier 50 and the methanator 60 in order to further increase the H1 concentration.
It has been established. In the #7 futo converter 55, the reaction Co + H, O→CO, + Ht further progresses in the presence of an appropriate catalyst, and the H! content and therefore the methane content in the product gas. In addition, 56 in FIG. 2 is a bypass, and the shift converter 5
This is to adjust the amount of gas sent to 5.

In the embodiment described above, air was used to oxidize the coal, but this may be oxygen gas or oxygen-enriched air.As described above, according to the present invention, coal is used as a raw material and is rich in methane and has a high calorific value. Gas can be produced. In addition, since it is based on a water gas reaction between H,i;

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a coal gasifier according to an embodiment of the present invention, and FIG. 332 is a block diagram of another embodiment. IO... Combustion furnace, 20.40... Dust collector, 50... Water gasifier, 55... Shift converter, 60... Methanator. Agent Tatsuyuki Unuma

Claims (2)

[Claims] (1) Partially burn coal in a combustion furnace to generate combustion exhaust gas containing unburned carbon-containing dust and carbon monoxide, react the unburned carbon-containing dust with steam to generate hydrogen, and then generate hydrogen. A coal gasification method characterized in that the generated hydrogen and the combustion exhaust gas are mixed and reacted with carbon monoxide in the carcass exhaust gas to generate methane. (2) Coal combustion furnace and skeleton combustion furnace discharge - A dust collector for collecting soot in the gas, and a reaction between unburned carbon in the soot and dust collected by the skeleton dust collector and water vapor. A coal gasifier comprising: a water gasifier for generating hydrogen; and a methanator for reacting the hydrogen generated by the water gasifier with carbon monoxide in the combustion furnace exhaust gas.