JPH01193588A - Atmosphere gas furnace equipped with exhaust combustion gas refining device - Google Patents

Abstract

PURPOSE:To return exhaust combustion gas, discharged out of a furnace, into the furnace as protecting gas and contrive energy saving, by a method wherein a heat exchanger is interposed between a discharging port and a gas cooler so that the exhaust combustion gas, discharged out of the discharging port of the atmosphere gas furnace to send it to the gas cooler, provides gas, sent to a supplying port from an oxidizing gas removing device, with heat to reduce the temperature thereof. CONSTITUTION:Exhaust combustion gas, generated by combustion in a heating device 14, is discharged out of a discharging port 17 and provides refined gas with heat in a space between the first introducing port 25 of a heat exchanger and the first delivery port 26 of the same while the temperature of the exhaust gas itself is reduced and the gas is sent to a gas cooler 3 to cool it suddenly to a temperature, lower than a temperature zone in which Boodore reaction is generated and capable of sending it into an oxidizing gas removing device. Cooled gas is sent into an oxidizing gas removing tower 21 through a compressor 4 to change it into refined gas, from which oxidizing gas is removed, and accumulate it temporarily in a pressure accumulating tank 23, thereafter, the refined gas passes through the second introducing port 27 of the heat exchanger 6 to the second delivery port 28. Under this process, the refined gas receives the sensible heat of the exhaust combustion gas and the temperature thereof is risen, then, the refined gas is sent into the heat treatment space 11 of the atmosphere gas furnace 1 through the protecting gas supplying port 13 of the atmosphere gas furnace 1.

Description

[Detailed description of the invention] The present invention aims to solve the following problems.

(Industrial Application Field) The present invention relates to an atmospheric furnace that heat-treats heat-treated materials in a protective gas, and more specifically, it purifies combustion exhaust gas generated from a heating device in an atmospheric furnace, and The present invention relates to an atmospheric furnace equipped with a combustion exhaust gas purification device, which uses the gas as a protective gas in the furnace.

(Prior art) In such an atmosphere furnace, combustion exhaust gas coming out of a heating device is rapidly cooled by passing through a gas cooler, and the cooled gas is passed through an oxidizing gas removal device to remove oxidizing gas. is removed and the remaining gas is returned to the atmosphere furnace as a protective gas. When carrying out the above cycle, unless the combustion exhaust gas is rapidly cooled, the equilibrium will be disrupted by the Boudouard reaction and the composition will become unstable, making it unusable. Based on this, in the above gas cooler, a large amount of cooling water is used to
The combustion exhaust gas at 0° C. is rapidly cooled to a temperature close to room temperature, for example, about 40° C., thereby making it possible to supply high-quality protective gas to the atmospheric furnace. However, in this case, the high thermal energy of the combustion exhaust gas from the atmospheric furnace is wasted, resulting in a large loss of thermal energy. In addition, the above-mentioned gas cooler has the problem of requiring a large amount of operating cost to rapidly cool the high-temperature combustion exhaust gas, and it is desired to solve these problems.

(Intelligence to be Solved by the Invention) This invention eliminates the above-mentioned conventional problems and allows the thermal energy in the flue gas discharged from the furnace to be returned to the furnace together with the gas returned to the furnace as a protective gas. An object of the present invention is to provide an atmospheric furnace with a combustion exhaust gas purification device that can save energy and at the same time keep operating costs of the gas cooler low.

The configuration of the present invention is as follows.

(Means for Solving the Problems) The present invention takes the measures as described in the claims above, and its effects are as follows.

(Operation) After the combustion exhaust gas discharged from the exhaust port passes through a heat exchanger, it is rapidly cooled in a gas cooler, and then the oxidizing gas is removed in an oxidizing gas removal device. The removed gas passes through the heat exchanger and is sent as a protective gas to the supply port in the post-atmosphere furnace. In the above case, the heat of the gas from the exhaust port to the gas cooler is given to the gas from the oxidizing gas removal device to the supply port in the heat exchanger. As a result, the gas reaching the supply port becomes hotter, while the gas reaching the gas cooler becomes colder.

(Embodiments) The drawings showing the embodiments of the present application will be explained below. 1 is an atmospheric furnace, 2 is a purification device connected to the atmospheric furnace, a gas cooler 3, a compressor 4 for gas transfer,
It has an oxidizing gas removal device 5 and a heat exchanger 6.

In the atmospheric furnace 1, 1o is a hollow furnace body, which has a heat treatment space 11 therein, in which a heat treatment material 12 is placed as is well known. Reference numeral 13 indicates a supply port for supplying protective gas to the heat treatment space 11. Reference numeral 14 indicates a heating device attached to the furnace body 10, which uses, for example, a radiant tube to heat the inside of the furnace by burning fuel. In this, 15 indicates a fuel supply port, 16 indicates an air supply port, and 17 indicates a combustion exhaust gas discharge port.
8 is a stirring device attached to the furnace body 1o, which, as is well known, has a fan 19 and a motor 20 for rotating the fan 19.

Next, in the oxidizing gas removal device 5, 21 and 21 are oxidizing gas removal towers, and as is well known, the two are used alternately. Reference numeral 22 denotes a suction pump, which is used when regenerating the removal column 21. 23 is a pressure accumulator tank, which is used to soften the shock when switching between the two removal towers 21 and 21.

Next, as is well known, the heat exchanger 6 has a first inlet 25, an outlet 26, a second inlet 27, and an outlet 28, which are piped as shown.

In the case of the above configuration, the heating device 14 of the atmospheric furnace l
The fuel supplied to the fuel supply port 15 is combusted by the air supplied to the air supply port 16 at an air fuel consumption of λ-1.0 or less. The heat generated by the combustion heats the protective gas inside the furnace, and the gas is stirred by the fan 19, so that the heat-treated material 12 inside the furnace is heat-treated. The heating device 14
The combustion exhaust gas generated by the combustion in is discharged from the exhaust port 17. Its composition is 1-2% CO and 1% CO2.
2-14% Hz O is 12-14%, H2 is 1-2%, and the temperature is 800-900'C. The above-mentioned combustion exhaust gas gives heat to the purified gas, which will be described later, during the period from the first inlet 25 to the first outlet 26 of the heat exchanger 6, and the temperature itself is lowered (for example, to 500° C.). The gas reaches the gas cooler 3, where it is rapidly cooled to a temperature below the temperature range in which the Boudouard reaction occurs and to a temperature at which it can be sent to the oxidizing gas removal device, for example, 40'C.

After passing through the compressor 4, the cooled gas reaches the oxidizing gas removal tower 21, where oxidizing gases such as COz, H, and O are removed, and becomes purified gas (purified exothermic gas). After the gas is temporarily stored in the pressure accumulator tank 23, it passes through the heat exchanger 6 from its second inlet 27 to its second outlet 28. In the process, the purified gas is kept at a low temperature (e.g. 1
The purified gas, which was at 0°C), absorbs the sensible heat of the combustion exhaust gas and becomes high in temperature (for example, 350°C), and the heated purified gas is sent to the protective gas supply port 13 of the atmosphere furnace 1, and from there the atmosphere It is sent into the heat treatment space 11 of the furnace 1.

When refining the flue gas generated by combustion of fuel in the heating device 14 as described above, the flue gas is used for NX Lean, so the flue gas is transferred to the heat exchanger 6.
Even if it is cooled once in the gas cooler 3 and then rapidly cooled in the gas cooler 3, the destabilization of the composition due to the collapse of the gas equilibrium is extremely small.
For example, the composition of the gas at the first outlet 26 of the heat exchanger is 0.8 to 1.8% CO and 12.2 to 14% COt.
．． 2%, H2C 12.2-14.2%, H7 0.8
~1.8%. Therefore, no problem arises in the use of purified gas as described above.

Next, the results of a trial calculation of the energy saving effect by using the heat exchanger 6 are as follows.

For 2 radiant tube burners: 80 n (N/h) Preheating temperature of purified gas to supply port 13: 350°C By using the heat exchanger 6, energy savings of, for example, 1 million yen per year can be achieved. Can be done.

(Effects of the Invention) As described above, in the present invention, the combustion exhaust gas discharged from the outlet 17 of the heating device 14 in the atmospheric furnace 1 is rapidly cooled in the gas cooler 3, and then oxidized in the oxidizing gas removal device 5. Of course, it is possible to remove the toxic gas and return the gas to the protective gas supply port 13 in the atmospheric furnace 1 for reuse as a protective gas in the furnace.In the above case, by providing the heat exchanger 6, , the heat of the gas going from the discharge port 17 to the gas cooler 3 is given to the gas going from the oxidizing gas removal device 5 to the supply port 13, so that the former gas becomes lower in temperature, while the latter gas becomes hotter. be.

The first point is that the gas returned from the supply port 13 into the furnace can be made to adapt to the high temperature gas in the furnace by adding only a small amount of thermal energy, and the second point is that: Regarding the gas going to gas cooler 3, the gas cooler 3 is used to cool the gas to a necessary and sufficient temperature.
The degree to which the temperature must be lowered is sufficient, and there is the advantage that the effect of reducing the equipment cost by downsizing the gas cooler 3, the effect of reducing the installation space, and the effect of keeping operating costs low at the same time.

[Brief explanation of the drawing]

The drawings show an embodiment of the present application, and FIG. 1 is a system diagram of an atmospheric furnace with a combustion exhaust gas purification device. DESCRIPTION OF SYMBOLS 1... Atmosphere furnace, 3... Gas cooler, 5... Oxidizing gas removal device, 6... Heat exchanger, 13... Protective gas supply port, 14... Heating device, 17... ...Exhaust port for combustion exhaust gas.

Claims (1)

[Claims] It has an atmosphere furnace equipped with a heating device that heats the inside of the furnace by burning fuel, and the exhaust port of the combustion exhaust gas in the heating device has a temperature range in which the Boudouard reaction occurs in the discharged combustion exhaust gas. A gas cooler is connected to the gas cooler for rapidly cooling the gas to the following temperature and at a temperature that can be sent to the oxidizing gas removal device, and the gas cooler is connected to the gas cooler to remove the oxidizing gas from the gas sent out from the gas cooler.
In an atmospheric furnace with a flue gas purification device connected to an oxidizing gas removal device that sends the removed gas to a protective gas supply port in the atmospheric furnace, a connection between the oxidizing gas removal device and the supply port is provided. A heat exchanger is interposed between the oxidizing gas removal device and the supply port to raise the temperature of the gas from the oxidizing gas removal device to the supply port using the heat of the combustion exhaust gas discharged from the exhaust port, and the heat exchanger intervening between the exhaust port and the gas cooler so that the combustion exhaust gas flowing from the exhaust port to the gas cooler is cooled by heat being given to the gas flowing from the oxidizing gas removal device to the supply port; Features: Atmospheric furnace with combustion exhaust gas purification device.