JPS58170515A - Apparatus for collecting dust and recovering heat from converter waste gas - Google Patents

Abstract

PURPOSE:To carry out dust collection and heat recovery of a converter waste gas, by supplying the gas at 800 deg.C to a moving bed type gas colling high temp. dust collecting part in which one end part of a heat pipe group is embedded to obtain a clean gas in a high heat recovery ratio and in a reduced waste water treating amount. CONSTITUTION:A waste gas from a converter 1 is directly subjected to heat recovery in a high temp. heat recovery part 4 in a high concn. state to lower the temp. thereof from about 1,450 deg.C to about 800 deg.C. In the next step, the treated gas is supplied to a moving bed type gas cooling high temp. dust collecting part 10 in which one end part of a heat pipe group 27 is embedded to carry out heat recovery as well as to lower the temp. thereof from about 800 deg.C to 300-350 deg.C while molten dust therein is collected in a stickiness free solidified state to enable the use thereof in a low temp. heat recovery part 14 comprising a usual heat exchanger. In addition, heat recovery from 300-350 deg.C to 100-150 deg.C is carried out in this low temp. heat recovery part 14. As the result, recovered energy becomes large and the sensible heat of the waste gas can be recovered within a range from about 1,450 deg.C to 100-150 deg.C while various apparatuses in the low temp. part are miniaturized to be made economical.

Description

[Detailed Description of the Invention] The present invention effectively collects the high-temperature retained heat discharged from the converter, removes dust such as bath molten iron grains, iron powder, and slag contained in the gas. This invention relates to a dust collection and heat recovery device for converter exhaust gas, which is recovered as fuel gas.

As is well known, converter exhaust gas has a high temperature of around 1460° C. and also contains dust such as molten iron particles, iron powder, and slag. However, since the gas contains a large amount of hydrogen and carbon oxides, a non-combustion treatment method has traditionally been adopted in which a certain amount of heat is recovered, followed by dust removal and cooling, and the gas is recovered as fuel gas. Particularly recently, from the viewpoint of energy conservation, this heat recovery and effective gas recovery have been actively carried out.

More recently, a process has been developed that actively produces carbon monoxide and hydrogen by injecting coal and steam into a converter at the same time as oxygen and gasifying the coal at the same time as iron refining. In such a case, it is desired that the heat recovery and the recovery of the useful gas be carried out particularly efficiently.

An example of a conventional processing method is as follows, and is a commonly used method. That is,
A high humidity collection section such as a waste heat boiler is provided in the converter gas duct, and heat is recovered from a temperature level of 1450°C to a temperature level of about 800°C. Note that it is not practical to recover heat to lower the gas temperature to a lower temperature level because the scattered dust, especially 6M iron and slazo, solidifies and causes blockage of the waste heat boiler. is considered impossible. Heat recovery in this part can only be performed up to a temperature at which the pickle, molten iron, and sludzo flow down in a slagging state without solidifying. Gas from the waste heat boiler is introduced directly into the quencher and cooled by water spray. At this time, most of the dust such as molten iron, iron powder, and slag is also removed. Then, if necessary, the gas is purified by passing it through a wet dust collector, etc., and then stored in a gas holder as fuel gas. As mentioned above, the conventional treatment method has an extremely poor heat recovery rate, does not require a large amount of quench water for cooling, and there is a large amount of dust in the converter gas, which can hardly be used until it is quenched. Since no dust was collected, a large amount of quench water was required to improve dust collection efficiency. As a result, the amount of wastewater naturally increases, and the wastewater treatment section has the disadvantage of becoming larger.

Now, the biggest cause of the above-mentioned drawbacks is the effective dry heat exchange that can process waste heat boiler outlet gas containing a large amount of dust from each camphor tree at approximately 800°C and recover heat ideally to below 100°C. The reason lies in the fact that the vessel does not exist. In other words, this gas not only contains a large amount of dust, but also contains dissolved iron and slazo, which become sticky and solidify when the temperature drops, so it is difficult to solve this problem. This makes it difficult.

The present invention has been made to solve the above-mentioned drawbacks.
A high-temperature heat recovery section is provided in the converter exhaust gas duct, and a moving bed type gas cooling plate made of spherical filter material such as mullite, silica, or alumina is installed downstream of this high-temperature heat recovery section, with one end of a group of heat pipes buried. A hot-dyed ASIG is connected, the other end of the heat pipe group is configured to flow a gas flow to be heated, and a low-temperature heat absorption section is provided in the downstream duct of the moving bed type gas-cooled high-temperature dust collection section, A water-washing cooling dust collection tower is connected downstream of this low-temperature heat absorption section, and further connected to a converter produced gas collection section via an induced blower. As a result, it is possible to provide a converter gas dust collecting and heat recovery device that has a high heat recovery rate, obtains clean gas, and requires a small amount of waste water to be treated.

Hereinafter, the structure of the present invention will be explained based on an embodiment shown inside. FIG. 1 shows the entire structure of the present invention, and FIG. 2 shows a gas cooling (heat recovery)/dust collection section which is the main part of the present invention.

Although FIG. 1 shows the entirety of this gas cooling/dust collecting section, the details of its construction are not shown, and the details are shown in FIG. 2.

(1) is a steelmaking converter that purifies molten pig iron by blowing oxygen or air into it. Incidentally, if pulverized coal and steam are blown into this converter (1) through a lance (not shown), the original form of a GL anvil coal gasifier will be constructed. In other words, when operating the copper converter (1), fuel gas containing hydrogen and carbon monoxide is produced, but by adding the above-mentioned coal, multiple hydrogen and carbon monoxide gases are produced over a longer period of time. is generated. This converter (1
) is connected to the converter exhaust gas duct (3) via the hood case (2), and a high-temperature heat recovery section (4), which is a waste heat boiler, is formed in the heat radiation section of the converter exhaust gas duct (3). do. In addition, (5) is a steam drum installed as needed, and (6) is its steam extraction pipe.

Downstream of the high-temperature heat recovery section (4), a spherical filter material (8) made of refractory material such as mullite, silica, or alumina is charged from the hopper (7) into the darkness of the louver support (9). A movable bed type dry gas cooling high temperature collecting section α0 having a laminar layer formed by being movably filled in a layered manner.
Connect. Here, this gas cooling A temperature collection pot αq has the configuration shown in FIG. 2 so as to have the performance of dry gas cooling and to be able to recover its heat. Note that FIG. 2 is viewed from a direction making a 90° angle with the viewing direction of FIG. 1. Here, one end of a dry heat pipe group is buried in a moving layer formed by a spherical filter material (8), and is supported by a partition wall (2) of the heat pipe group to form a heat dissipation section. The other end is exposed on the fourth side. A heat carrier is a heat transfer medium for heat recovery, usually a gaseous medium such as air for combustion.

In addition, in Figures 1 and 2, Qυ is the dust separator (
sieve), υ is the dust removal pipe.

A low-temperature heat recovery section α4, such as a normal heat exchanger, is installed in the downstream duct of the gas-cooled high-temperature dust collection section α.

This low-temperature heat recovery section 04 is composed of a tube-and-cell heat exchanger in FIG. ), but it is not necessary to use such a heat exchanger, and a rotary heat storage type heat exchanger may also be used. A water quench type cooling dust collection tower (b) is connected downstream.

Here, (f) is a water supply pipe that supplies cooling water to the water sprinkler pipe (g) of the cooling collection tower (17), and (e) is a waste water outlet pipe. (2) is a mist separator connected to the outlet side of the cooling clam tower αη, (c) is an exhaust gas induced blower, (F) is a switching valve, (4) is an ah gas holder, (e)
is a flare stack.

In the apparatus configured as above, the gas discharged from the converter (1) is at a high temperature of 1450°C, and the temperature is 1QQ.
Co, %e, including dust with high concentration of f/Hw1 or more
co! .

It is a gas made up of things like horses. What is characteristic is that the dust is mostly in a molten state, and the dust components are made up of iron, slap, and other miscellaneous materials. Such gas passes through the duct (3) and is introduced into the high temperature heat recovery section (4) where the heat is recovered. However, the heat recovery here is limited to about 800'ct, and it is practically difficult to recover heat to a temperature lower than that. Because S.O.
This is because at temperatures below 0°C, the above-mentioned molten dust solidifies, solidifying inside the heat exchanger and causing a phenomenon in which the function of the heat exchanger is stopped. When the temperature is 800° C. or higher, the dust flows down along the pipe wall in a slagging state, so there is no major problem.

Conventionally, even if this molten dust solidifies, it does not cause any adverse effects, and it has been used in low temperature ranges such as 800°C to 400'c.
Until now, there was no equipment that had the ability to recover heat and collect dust, so we decided to use a direct water quench method to cool the 800°C gas and collect dust, knowing that there would be a large heat loss and a large burden of water treatment. They were introducing it into the tower and processing it. In the present invention, gas at SOO° C. is supplied to a moving bed type gas-cooled high-temperature dust collection section αQ in which one end of a pipe group is buried, thereby solving the conventional drawbacks and eliminating large losses. In other words, the exhaust gas that crosses the louver support (9) and is introduced into the moving layer composed of the spherical filter material (8) in which the heat pipe group is embedded is heated by the heat vibrator W#. The n1 heat transferred to the body is recovered. At this time, the exhaust gas is naturally cooled and reaches a temperature of 800 to 850°C at the exit of the moving bed.

By cooling during this time, the molten dust present in the exhaust gas solidifies, but this dust adheres to and is captured by a spherical filter material (8 mm) and is filtered, reducing to a few 2 particles on the exit side.

Here, a spherical filter material (a spherical filter material made by molding a refractory material such as mullite, silica, or alumina) is preferable, and coke, which is generally proposed to be used in a moving bed dust collector, is recommended. Irregularly shaped crushed products such as , coal, and sand are not preferable, because although these are certainly efficient in terms of dust capture rate, the dust here is molten iron, #I molten slag, etc. Since it is captured while solidifying, with such filter media, after filtration,
This is because it is almost impossible to separate these. On the other hand, the spherical filter material t molded from the refractory material used in the present invention has a loose dust-adhesive part, and is easily separated by a dust separator (b) such as a vibrating sieve. Ru. Therefore, the filter material after separation can be repeatedly used by returning it to the hopper (7) by an appropriate means such as a packet elevator (toward), which is economical.

The amount of dust in the gas that exits the gas cooling high temperature dust collection section (G) is several y/Md as mentioned above, but at the same time the gas temperature is lowered to 800-860°C, so this dust It has completely solidified and lost its viscous properties as in the molten state. Therefore, the low-temperature heat collection section (B) installed downstream of this gas-cooled high-temperature dust collection section (B) uses commonly used tube-and-cell type heat exchangers, rotary heat storage type heat exchangers, etc. It is possible. Heat is recovered from a temperature of 800 to 850°C to 100 to 150'C in this low temperature heat recovery section α◆.

Finally, it is introduced into a water quench type cooling dust collection tower αη, where it is deafened to several tens of mV″M- and cooled to around 60°C, and water droplets are removed by a mist separator (2). , a clean gas containing % and Co. This gas is used directly via the exhaust gas induced blower or stored in the gas holder (E). In addition, at the start of operation, etc.
If it does not contain sufficiently high concentrations of ii, , and co, operate the switching valve ① to burn and release it from the flare stack (e). In addition, the wastewater discharged from the wastewater collection pipe of the water quench type cooling dust collection tower (Foundation) is cooled and treated as necessary to remove dust, and then cooled by being supplied from the water supply Vibe Q. It may also be circulated as water.

As described above in detail, the converter exhaust gas collection and
The heat recovery device recovers heat from the converter exhaust gas in a high-temperature heat recovery section while keeping it at a high concentration (approximately 1450℃ to approximately 800℃), and then one end of the heat pipe group is removed (approximately 800℃).
℃ to 80℃ (h850℃), the molten dust is solidified and collected to eliminate the viscosity of the dust, making it possible to use a low-temperature heat collection section consisting of an ordinary heat exchanger, and to recover the low-temperature heat. The unit is configured to recover heat from 80 () -850℃ to 100 to 150℃, so the sensible heat of the exhaust gas is recovered from approximately 1450℃ to 10
It can be recovered up to 0 to 150°C, and the various devices in the low-temperature section are miniaturized, making it economical. In particular, the reduction in the amount of water used in the water-cooled dust collection tower and the amount of wastewater treatment required are extremely significant.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention; FIG. 1 is a diagram of its overall configuration, and FIG. 2 is a diagram of its essential parts. (1)...Converter for steelmaking, (3)...Converter exhaust gas duct, (4)...High temperature heat absorption section, (8)--Spherical filter material, (9--Louver support , 0Q...Gas cooling high temperature collection section, α◆...Low temperature heat collection section, αη...Water cooling dust collection tower, Su...Exhaust gas induced blower, (c)...Gas holder, (Support)...Heat vibrator group, Han...Heat dissipation part

Claims (1)

[Claims] 1. A high-temperature heat recovery section is installed in the converter exhaust gas duct, and one end of the heat vibrator group is buried downstream of this high-temperature heat recovery section. A gas-cooled straw-warming dust collection section is connected, and a heated gas flow is made to flow through the other end of the heat vibe group, and low-temperature heat is recovered to the downstream duct of the moving bed type gas-cooled high-temperature collector. A water-cooled dust collection tower is connected downstream of the low-temperature heat recovery section, and a converter generated gas recovery section is connected to the awn via an induced blower.・Heat recovery equipment.