JPS5812A - Effective use of factory waste gas - Google Patents

Abstract

PURPOSE:To enable effective recovery of waste gas heat energy, as of a steel mill, by the use of high-temperature exhaust gas with a specified O2 concentration in order to dry and grind solid fuel such as coal. CONSTITUTION:The factory waste gas with a ten percent or less O2 concentration is led to the heat exchanger for heat recovery. Then, the waste gas now maintained at temperatures of 200-400 deg.C is fed to the device which is designed to dry and grind solid reducing agents. Then, the waste gas now maintained at temperatures of 60-120 deg.C is led to a dust collector to be made free of dust. This not only enables effective use of waste gas heat energy, but also provides ease of removal of dust from waste gas. Besides, this provides at low cost the hot blast required for drying and grinding solid reducing agents including coal.

Description

[Detailed description of the invention] This invention relates to a method for effectively utilizing factory exhaust gas.

41 relates to the effective use of exhaust gas flowing into a factory where solid reducing agents and the like are dried using hot air, and where the exhaust gas temperature is 400 to 1000°C.

Exhaust gas from rice mills, smelters, etc. has an elemental degree of 10 or less and contains harmful dust.

No effective method for recovering energy from exhaust gas, which has temperatures of 400 to 1000 degrees Celsius, could be found.

φ For example, if exhaust heat is effectively recovered using a heat exchanger, only enough energy can be recovered to reach a temperature of 200 to 400°C at the outlet of the #Il exchanger, and if it is not further cooled, dust in the exhaust gas Such bugs could not be removed with a simple dust collector.

On the other hand, in factories that use the solid reducing agent of Ishitatemisaki as a reducing agent, it is necessary to produce hot air with low oxygen content and a low temperature of 500 to 600° C. for drying and pulverization.

This means that if the elemental degree is 10 or more, the explosion limit of ○H3 will be high and dangerous, and if the temperature is too high, even if the oxygen level is low, the R elements in the reducing agent will This is because combustion or fusion may occur, leading to other problems.

The present invention solves the above-mentioned problems of the conventional technology. (1) Effectively uses the thermal energy of exhaust gas, (2) Easily removes dust in the exhaust gas, and at the same time reduces O coal and other solids. This is an inexpensive way to obtain hot air for drying and pulverizing chemicals.

In other words, the present invention introduces the factory exhaust gas of 0.10 s or less into a heat exchanger, recovers the heat, and then introduces the exhaust gas whose temperature is less than 200 to 400 C to a device that also dries and crushes the solid reducing agent. This invention relates to a method for effectively utilizing factory exhaust gas, which involves introducing the exhaust gas at a temperature of 940 to 120°C into a dust collector and collecting the dust to remove mold.

The present invention will be explained in detail below.

The exhaust gas targeted by the present invention is a factory exhaust gas with a 0-degree degree of 10- or less. There are many factors in factory exhaust gas, but 1%
The exhaust gas generated in smelters, etc. has an exhaust gas temperature of 400 to
As high as 1000℃.

It is normal that the amount of dust is 2~S　O11B-.

Heat is recovered from the exhaust gas until the outlet gas temperature falls within a temperature range where heat can be easily recovered by the M exchanger, that is, from 200 to 400°C.

For example, in an electric furnace in ferronickel smelting, exhaust gas equivalent to approximately 100 to 200 Nvd of exhaust gas electricity is generated.
The exhaust gas temperature is as high as 400 to 1000°C, and the amount of dust is as high as 5 to 12 fl/M/.

In order to heat exchange cough gas with cold air using a heat exchanger, the amount of cold air required is about 200 to 1000 k1/min.

After heat exchange, the cold air changes to hot air at 200℃.

It is used to preheat ore together with heavy oil or coal in kilns, etc. This will reduce the amount of heavy oil used in kilns and the like.

On the other hand, the exhaust gas after heat exchange is <200 to 400 as described above.
Since the exhaust gas temperature is less than ℃, the more effective use of this exhaust gas will strongly promote energy conservation.

In the present invention, the exhaust gas from the heat exchanger is used for drying and pulverizing the solid reducing agent.

When a solid reducing agent is used, for example, 1 coal, explosion due to generation becomes a problem.

However, in smelting exhaust gas whose temperature has been lowered to less than 200 to 400°C, it is not present at all.

There is no problem of cough explosion. This is also due to the fact that the number of carbon atoms in the exhaust gas is as low as 1091 or less.

Therefore, the solid reducing agent is dried and pulverized at the same time, allowing highly safe operation.

Grinding and drying are carried out by, for example, introducing a solid reducing agent into a grinding machine having grinding rollers and a rotary table from the upper part, and charging the above-mentioned exhaust gas for drying and grinding from the lower part. compression.

The solid reducing agent pulverized by shearing and wind pressure, or the solid reducing agent already in the form of powder, or the coal for combustion is transported by pneumatic flow together with the exhaust gas charged from the bottom,
dried.

By passing the gas through a cyclone, the pulverized solid additive and the dust in the exhaust gas, which have been carried away and dried by the exhaust gas, are recovered. The recovery rate of the isomeric reducing agent in this case is 951 or more.

The solid reducing agent is also dried to a moisture content of about 7 to less than about 2.

Furthermore, the dust and fine powder reducing agent that could not be recovered by the cyclone are collected by a dust collector consisting of a filter.

On the other hand, the exhaust gas temperature at the inlet of the dust collector is 1.60 to 120℃
As a result, it was demonstrated that the energy possessed by the exhaust gas was sufficiently used for drying.

In addition, the cough dust collector has an exhaust gas temperature of 40 to 120°C, and the present invention is applied to smelting exhaust gas.

The solid reducing agent is recovered together with the dust, but the skeleton dust is used again as a raw material for smelting and is ToD.

Also, since this reducing agent is added to &@,
The contamination of dust is not a disadvantage; on the contrary, it has the effect of preventing the loss of raw materials.

By carrying out the present invention as described above, the following effects can be obtained.

(1) It enables heat recovery and effective heat utilization of exhaust gas of 400 to 1000°C.

) Provides hot air for drying solid reducing agents, etc. at low cost.

Moreover, there is no danger of explosion due to OH, etc., and safe operation in the crushing and drying process is possible.

(2) Furthermore, since sufficient heat is utilized until the exhaust gas temperature reaches 60 to 120°C, it becomes possible to collect dust in the exhaust gas using a simple dust collection equipment at the final exhaust gas outlet.

0) While drying the transportation of solid storm base materials, etc. to long distances,
possible.

φ) It is possible to supply clear preheated hot air of around 200℃.

Examples of the present invention will be shown below.

Example Exhaust gas (s o
The present invention was carried out for OM, //min, temperature 9850°C).

The exhaust gas is passed through a heat exchanger and cooled air (600 MII/min.

Heat exchange was performed at 25°C. The cold air at the outlet of the heat exchanger rose to a temperature of 200° C. and was used as hot air for preheating the kiln.

On the other hand, the exhaust gas from the electric furnace maintained a high temperature of 550°C after leaving the heat exchanger, so it was used for the 1-coal drying equipment.

Exhaust gas is o*7%, 00s 29-, bird 64
Since it has a SO composition and a sufficiently low alX content, there was no risk of explosion due to the generation of OH- and toxins, which is a problem in coal pulverization.

A first-order mill was used to crush the coal. That is, it has a crushing roller and a rotating bottom plate, and coal is introduced from the top.

While being pulverized by the rollers, the fine powder blown away by the exhaust gas charged from the bottom is collected by a dust collector in the next step.

Therefore, coal having a particle size that cannot be blown away remains in the mill and is sufficiently pulverized by the rollers.

Coal is sufficiently dried not only in the mill but also in the first step, the coal collector.

As the gourd collector, a cyclone was used in the first step, and a bag filter was used in the second step. In the first process, 95 units of the input coal was recovered, and in the second process, the remaining 5 units were recovered.

The exhaust gas is used for drying and as a result, the exhaust gas is
The temperature was 50°C, but it dropped to 80°C at the exit of the bag filter, which is the second step.

For this reason, the P cloth of the bag filter was never worn out due to heat, and dust collection was possible in a simple and highly efficient manner.

Incidentally, the dust contained in the exhaust gas) 1ar, /MI
I/ was also effectively collected with a recovery rate of over 99.99-.

Part of the recovered pulverized coal was mixed with heavy oil for the kiln and used as fuel, and the rest was mixed with the raw material ferronickel ore and effectively used for preliminary reduction.

For patent purposes, ``Japan Mining Co., Ltd. Agent 1st Examination (7569) Parallel Keishi Proceedings Amendment Written August 22, 1980 Commissioner of the Patent Office Shima 1) Haruki Tono 1. 44 Displays 1982 Patent Application No. 97539 No. 2. Name of the invention: Method for effectively utilizing factory exhaust gas. In-house corporation & date of amendment order Column for detailed description of specification subject to amendment l Contents of amendment Form 4 Jj 1st line r 100-20ONI?/
/min" is corrected to "100-400 kbd/min."

Claims (1)

[Claims] 011〇 - After introducing the following factory exhaust gas into a heat exchanger, and introducing the exhaust gas whose temperature has become below 200 to 400℃ after heat treatment into a device that doubles as drying and pulverization of solid reducing agent or coal for combustion, etc. A method for effectively utilizing factory exhaust gas, in which the exhaust gas, which has reached a temperature of 60 to 120°C, is introduced into a dust collector and collected to remove mold.