JPS59206490A - Apparatus for drawing out coal ash slag - Google Patents

Abstract

PURPOSE:To keep the calorific value of the produced gas constant even during the fluctuation of load and to prevent a slag discharge port from being clogged without lowering gasification efficiency, by embedding an electric resistance-heating unit in the area of a molten slag discharge port. CONSTITUTION:Pulverized coal 21 and oxygen 22 are fed to a gasifying chamber 1 and partially burnt to gasify the coal 21 while keeping the temp. at a level not lower than the melting temp. of ash contained in the coal, and the produced gas 23 is recovered from the upper part. Ash contained in the coal 21 is allowed to flow in a molten state through a slag discharge port 2 into a cooler 3 to cool and solidify it with cooling water 24. A coil heating unit 8 is embedded in the slag discharge port 2, and a lead wire 9 is connected to both terminals of the heating unit 8. The temp. of the slag discharge port 2 is controlled to a temp. not lower than the m.p. of the ash in the coal by the heating unit 8, whereby molten slag is prevented from being solidified on the way of the slag discharge port 2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a device for extracting coal ash slag from a spouted bed coal gasifier.

[Background of the invention]

The temperature of the slag discharge hole (hereinafter referred to as slag tap) in a spouted bed gasifier is determined by the balance between the heat supplied from the highest gasification section (heat input) and the heat dissipated to the section that cools the molten ash (heat output). It is determined by Therefore, when the load on the gasifier decreases, the heat input decreases and the temperature of the slag tap decreases. As the temperature of the slag tap decreases, the molten ash flowing down also cools and its viscosity increases, making it difficult to flow down.If the temperature further decreases, the ash solidifies and the slag tap becomes clogged. One way to prevent slag tap clogging during load reduction is to increase the proportion of oxygen supplied to coal.
An increase in the oxygen-to-coal ratio has the disadvantage of reducing the amount of combustible gas generated per unit of coal, deteriorating the gasification efficiency, and changing the calorific value of the produced gas. Also, heat the slag tap,
JP-A-57-172 as a device that improves slag removal
No. 986 has been proposed. This technology uses a slag tap as a formed brick, wraps the outer periphery of the formed brick with insulating concrete, embeds a water-cooled inductance coil in the insulated concrete, and applies a frequency to the coil to create a slag tap of the formed brick. This is a method of induction heating.

Therefore, since heating the slag tap is an indirect method of heat transfer from the insulated concrete embedded coil to the molded bricks, the responsiveness of temperature adjustment during load fluctuations during gasification operation is not necessarily good. . Furthermore, since cooling water is used, the structure around the slag tap becomes large and complicated. Furthermore, stopping the cooling water will cause coil burnout, so it is necessary to take measures to prevent water outages.

As a result of the above, there are problems with temperature control of the slag tap and reliability in terms of device operation.

[Purpose of the invention]

The present invention has been made in an attempt to improve the above-mentioned drawbacks.
The purpose is to prevent the slag tap from clogging without reducing the gasification efficiency even when the load fluctuates.

[Summary of the invention]

That is, the features of the present invention include a gasification chamber that partially oxidizes coal with oxygen or an oxygen-containing gas and gasifies the coal by maintaining it at a temperature higher than the melting temperature of ash in the coal; A spout bed coal gasification furnace having a slag discharge hole for discharging ash in a molten state from a gasification chamber to a slag cooler, a coal ash slag extraction device comprising an electric resistance heating element embedded in the slag discharge hole portion. Nichiru.

[Embodiments of the invention]

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

In FIG. 1, pulverized coal 21 is conveyed with nitrogen gas, is supplied to a nozzle 6 together with oxygen 22, and is sprayed into the gasification chamber 1 from the tip of the nozzle 6. The pulverized coal 21 sprayed from the nozzle 6 is partially combusted by oxygen and converted into a combustible gas rich in carbon oxide and hydrogen, which is taken out upward as a generated gas 23. The ash contained in the coal is melted by the heat generated by partial combustion, and a part of it adheres to the inner wall of the refractory 5 covering the gasification chamber 1, gradually flows down the wall surface, and cools the slag from the slag tap 2. It falls into vessel 3. Cooling water is stored in the lower part of the slag cooler 3, and this cooling water is supplied to the large mouth valve 24.
Alternatively, the output valve 25 may be adjusted to maintain a constant amount at all times. The ash that has fallen into the slag cooler 3 is submerged in the cooling water and solidified, and is taken out by opening the valve 7- at regular intervals.

The refractory 5 is housed in the pressure vessel 4, thereby enabling gasification under pressure. The refractory 5 serves as a heat insulator to maintain the gasification chamber 1 at a high temperature, and at the same time prevents molten coal ash from coming into contact with metal parts including the pressure vessel 4 and causing corrosion.

The shape of gasification chamber 1 is 200 m in diameter and 800 m in height +++
The upper part of the cylinder from which the produced gas 23 is taken out is narrowed to a diameter of 100 cm. Similarly, the slag tap 2 has a diameter of 50y* and a length of 30mm in the initial state.

In FIGS. 2 to 4, a coiled heating element 8 is embedded in the slug tap 2, and electrical lead wires 9 are provided at both ends. The energizing lead wire 9 is preferably made of nickel or nichrome wire, and in order to maintain insulation from the slag cooler 3,
It is inserted into a protective tube made of ceramics, etc. To manufacture the slag tap 2, a large material such as alumina cement is injected with water and kneaded, and a coiled heating element 8, which has been previously formed into a spiral shape, is placed horizontally in a mold and allowed to dry and solidify naturally. Here, there is a possibility that the slag tap 2 may be maintained at a degree of 1300 to 1500♂ which is higher than the melting point of the ash in the coal.

For this reason, when embedding the coiled heating element 8 in the muddy alumina cent, it is important to wrap the coil with fibers such as gauze. In other words, fibers such as gauze have 300 to 40
Because it burns out at 0C, a gap is created at the contact surface between the refractory and the coiled heating element 8, and even if the coiled heating element 8 has an extension in a high temperature state, the gap creates a gap between the coiled heating element 8 and the refractory. The tension on both sides is relaxed, and damage to the slag tap 2 can be prevented.

The slag is extracted in the spouted bed gasifier operation by installing the slag tap 2 shown in FIG. 4 in the following manner. Gasification operates at temperatures above the melting point of the ash in the coal, so
By adjusting the temperature of the slag tap 2 to this temperature, the slag can flow down to the slag cooler 3 without solidifying in the middle of the slag tap 2.

The temperature of the slug tap 2 can be determined by connecting a measuring device (not shown) that can measure current, voltage, or power values to the lead wire 9 that conducts electricity, or by detecting the input value to the heating element. The temperature of slag tap 2 can be calculated from As a result, a current regulator such as a system slide transformer is operated manually or automatically to adjust the temperature to around the melting temperature of the ash. The temperature of the slag tap 2 must be set within a certain range. If the set temperature is low, the slag will solidify before passing through the slag tap 2, resulting in blockage. Also,
If the set temperature is too high, the life of the slag tap 2 itself or the heating element will be shortened, so it is important to set it near the melting point temperature of the ash.

Examples and comparative examples of gasification operation using the slag tap of the present invention will be described below. In the equipment shown in Figures 1 and 4, pulverized coal 2
The Pacific coal whose properties are shown in Table 1 as 1 is 4 to 12 to 30.
/h, oxygen 22 was supplied 9/h from 10 to 24, and the temperature of the slag tap was varied. The results are shown in Table 2.

Table 1 In Table 2, at 100 inch load, slag tap temperature 1a2
When the device was operated with the temperature set at oc (temperature converted from input value detection), the normal state continued for 10 hours.

As a comparative example, when the slag tap was operated at 100% load without energization, the slag tap 2 became clogged in about 3 hours. Further, as described above, normal operation was possible with heating of the slag tap at 83% load, but the slag tap was clogged in about 1 hour without heating. Furthermore, with a 53-chi load, the heating temperature of the slag tap was varied and the operation was performed. As a result, when the slag tap temperature was 1320r, it was in a normal state, but when the temperature was lowered to 1100c, the slag tap was closed after about 1 hour.

As described above, by heating the slag tap by applying electricity from outside, the slag could be extracted successfully.

5 and 7 show other embodiments of the invention.

First, in FIG. 5, a coiled heating element is inserted into a refractory similarly to that shown in FIG. 2, and here it is inserted vertically around a hole through which slag flows. FIG. 6 is a sectional view taken along line BB in FIG. 5, and the coiled heating element 8 has a spiral shape. According to this structure, the slug tap 2
The surrounding area of the slag flow hole can be heated.

It is also possible to use a heating element that is a combination of the spiral coil shown in FIG. 2 and the spiral coil shown in FIG. 5.

FIG. 7 shows a cylindrical heating element, which is made of a fire-resistant insulator, and generates heat when the insulator 10 is energized. FIG. 8 is a developed view obtained by processing the above-mentioned FIG. 7, in which grooves 11 are cut alternately on the upper and lower sides in order to increase the effective current-carrying length of the insulator. If the heating element 10 has high heat resistance and can withstand the melting point temperature of ash, it is possible to fix the outer periphery of the heating element with the refractory 5 of the gasification chamber 1.
Can be used directly as a slug tap.

As described above, in the present invention, since the slag tap itself is used as a heating element, the responsiveness and operability of temperature adjustment are good, the area around the slag tap can be made compact, and the reliability of the device operation is also good.

〔Effect of the invention〕

According to the present invention, it is possible to keep the generated gas calorific value constant even during load fluctuations, and to prevent slag tap clogging without reducing gasification efficiency.

[Brief explanation of the drawing]

Fig. 1 is an equipment diagram for explaining a spouted bed gasifier, Fig. 2 is a longitudinal cross-sectional view of the slag tap of the present invention, and Fig. 3 is a line A-A in Fig. 2.
4 is a schematic sectional view of the slag tap shown in FIG. 2 attached to the gasifier shown in FIG. 1, FIG. 5 is a longitudinal sectional view of another slag tap of the present invention, and FIG. BB sectional view in Figure 5,
FIG. 7 is a perspective view of another slug tap of the present invention, and FIG. 8 is a developed view of FIG. 7. Engineering: Gasification chamber, 2: Slag tap, 6: Nozzle, 8: Coiled heating element, 9: Lead wire, 1
0... Cylindrical heating element, 21... Pulverized coal, 22...
Oxygen, 23...Produced gas. Funeral 1 Figure 3 Figure Dice - 4 Figure 77 Figure 10 Army Figure 8 Continuation of Page 1 0 Inventor Hiroshi Miyadera 3-1-1 Saiwaimachi, Hitachi City Stock% Formula % @ Applicant Babcock Hitachi Stock Company 2-6-2 Otemachi, Chiyoda-ku, Tokyo

Claims (1)

[Claims] 1. A gasification chamber that partially oxidizes coal with oxygen or oxygen-containing gas and gasifies the coal by maintaining it at a temperature higher than the melting temperature of the ash in the coal; A device for extracting coal ash slag, characterized in that a spout bed coal gasifier has a slag discharge hole for discharging water to a slag cooler, and an electric resistance heating element is embedded in the slag discharge hole portion.