JPS5815713B2 - Atmosphere heating furnace - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an atmosphere heating furnace that increases thermal efficiency and suppresses fuel consumption.

More specifically, the nitrogen component and oxygen component in the atmosphere are separated and purified, the nitrogen component is not used as a protective atmosphere gas, and the sulfur component is used as combustion oxygen in a heating burner, or The present invention relates to an atmosphere heating furnace in which the combustion air of a row heat burner is mixed and added to increase the combustion efficiency of the heating burner and reduce or suppress fuel consumption.

Conventionally, when nitrogen gas is separated and purified from the atmosphere, the oxygen gas that is separated and removed at the same time is wasted into the atmosphere, so it is desired to make effective use of this.

In particular, when nitrogen gas is added to an atmosphere heating furnace that uses nitrogen gas as part of the atmospheric gas, oxygen gas other than nitrogen gas purified from the atmosphere is thrown away into the atmosphere.

□The present inventors have made the invention in order to eliminate the above-mentioned waste of the separated oxygen gas generated during the purification of the nitrogen gas used in the atmosphere of the atmosphere heating furnace.

The purpose of the present invention is to separate and refine the atmosphere into nitrogen gas and oxygen gas, to inject the nitrogen gas into the heating furnace as a protective atmosphere gas, and to burn the oxygen gas in a heating burner such as a radiant tube. Therefore, an object of the present invention is to provide an atmosphere heating furnace in which oxygen is added alone or as a mixture with air.The object of the present invention is therefore to significantly raise and reduce the combustion temperature by adding oxygen, thereby increasing the combustion efficiency. By reducing the amount of combustion air by the proportion of oxygen gas added, the amount of heat carried out by the combustion waste gas is reduced, increasing the overall thermal efficiency of the heating furnace. To provide an atmosphere heating furnace that is economically advantageous by reducing operating costs) and reducing costs.

Another object of the present invention is to measure the dew point and the amount of acid ice in the carbon dioxide region in the furnace and add hydrocarbon gas to adjust and control the oxidation and decarburization of the material to be treated. Provide a furnace.

゛. Next, two preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows a longitudinal sectional front view of the atmosphere heating furnace, and FIG. 2 shows a side view of the same.

The heating furnace used in the present invention is a radiant tube type,
The heating furnace 1 consists of a furnace body 2 made of refractory material and an outer wall 3 surrounding the outside.

A mounting table 4 for the workpiece W is provided on the floor 2a of the main body 2, and radiant tubes 6 are provided on the left and right sides of the furnace chamber 5.
．． 6 is arranged hanging down.

The radiant tube 6.6 has a U-shape as shown in FIG. 2, with the main body 6a facing into the furnace chamber 5, and the inlet 6b passing vertically through the furnace main body 2 and the ceilings 2b and 3b of the outer wall 3 and extending upward. The outlet section 6c is also exposed upward through the ceilings 2b and 3b, and is connected to the air passageway. The portions of each burner 7, 621 and 6-2, are connected to a fuel gas supply source through a thread 8, and fuel gas alone or a mixture of fuel gas and air is supplied to the burner 7.

. In conclusion, an air separation device is provided outside the furnace 1, specifically an adsorption tower 8, and the upstream side of the adsorption tower 8 is communicated with the atmosphere via a cooler 9.

The adsorption tower 8 separates and refines the air introduced from the cooler 9 into oxygen gas and nitrogen gas, and the nitrogen gas is sent to the furnace 1 via a pipe 10.
is supplied to a nozzle 11 installed vertically in the ceilings 3b, 2b of the furnace chamber 5, and introduced into the furnace chamber 5.

On the other hand, the separated and purified acid solution gas is sent to the burner 1 of the radiant tube 6 through a pipe line 13 equipped with a pump 12 such as a vacuum pump, and the radiant tube 6 has 6-L on the left and right.
6-2, each burner 1 has a branch path 13a.
, 13b.

Oxygen gas is fed to the burner 7 either as a single oxygen gas or mixed with air! In addition, the nitrogen gas supplied through the pipe 10 is used as part or all of the atmosphere gas component for heat treatment.
The gas atmosphere detection device 1 is installed vertically on the ceilings 2b and 3b of the
4 is attached, which notifies the gas analyzer 15 outside the furnace of the atmosphere.

On the other hand, a nozzle 16 is provided extending vertically through the ceilings 2b and 3b, and is connected to a hydrocarbon gas source via a pipe 11.

A control valve 18 is interposed in this conduit 17, and the control valve 18 is connected to the gas analyzer 15 described above.
The control pulp 15 is selectively opened and closed based on information about the atmosphere inside the furnace chamber 5, and hydrocarbons are supplied into the furnace chamber 5.

In the above, nitrogen gas separated and purified from the air is supplied into the furnace chamber 5 through the nozzle 11, and oxygen gas (normally, the oxygen in the air is reduced to 35% or more by purification) (i.e. oxygen-enriched gas)
Oxygen gas is supplied to the burner 7 of the radiant tube 6-1, 6-2, and is added at a predetermined ratio as oxygen gas alone or as a mixture with combustion air, and is used for combustion.

As a result, the combustion temperature within the radiant tube increases significantly, and the amount of combustion air can be reduced by the proportion of oxygen gas, reducing the amount of heat taken out of the combustion waste gas and improving the overall thermal efficiency of the heating furnace. .

As a result, fuel gas consumption is reduced, and operating costs can be reduced.

. By the way, when the material to be treated is put into a heating furnace and subjected to heat treatment, it has traditionally been the principle that it is washed, but due to problems with wastewater treatment, the material to be treated is sometimes put into the furnace as is after heating. are becoming more common.

For this reason, oil, water, etc. adhering to the surface of the workpiece are brought into the furnace, causing variations in the amount of carbon dioxide and oxygen in the protective atmosphere inside the furnace, which causes oxidation, decarburization, etc. A problem is occurring.

The present invention is equipped with the above-mentioned furnace atmosphere sensor 14, which detects the air between the wires, sends it to the analyzer 15, and analyzes it to determine the dew point, oxygen amount, and dioxide of the furnace atmosphere. Control pulp 18.
A necessary amount of hydrocarbon gas, such as propane gas, is introduced into the furnace and added to the atmosphere to protect the workpiece from acid peaks and decarburization.

Next, concrete implementation of the present invention will be described.

6:: Goods.

, 6, 7, A, 7, U. Using a radiant tube type heating furnace that heats up to 900°C, 100 pieces of the workpiece are heated.
When processing 0 kQ/H, about 12 m/H of butane gas was consumed as heating fuel.

On the other hand, as a protective atmosphere gas in the furnace, an exothermic gas mainly composed of nitrogen gas was required at a rate of about 5 om/H.

The butane gas required to generate this protective atmosphere gas was approximately 2577//H.

The present invention uses a resistant tube type heating furnace that heats from room temperature to 900°C in an atmospheric heating furnace with an internal furnace volume of about 10°C.
When processing 1000 kg/H of the material to be treated, when 12 n//H of oxygen gas separated and purified from the atmosphere was mixed and added to the combustion air of the heating combustion burner, the consumption of butane gas was 10 m//H, While it was found that fuel consumption was significantly suppressed and reduced compared to conventional methods, nitrogen gas, which was separated and purified at the same time as oxygen gas, was used as the atmosphere gas in the furnace, but it caused oxidation and decarburization of the processed products. As is clear from the above, according to the present invention, atmospheric air is separated and purified into nitrogen gas and oxygen gas, and nitrogen gas is introduced into the furnace and used as a protective atmosphere gas. The oxygen gas generated during nitrogen gas purification is used as a combustion aid and accelerator for the radiant tube, either alone or mixed with the combustion air, so oxygen gas is used without waste, improving combustion efficiency and reducing fuel consumption. It is possible to reduce the operating cost of this type of heating furnace, reduce the cost of processed products, and reasonably achieve energy savings.

Since an atmosphere sensor is installed in the above furnace and hydrocarbons are supplied into the furnace and controlled according to the atmosphere, decarburization and oxidation of the material to be treated can be prevented, resulting in a good quality of the material being treated. Processed products can be obtained.

[Brief explanation of the drawing]

The plan view shows one embodiment of the present invention, and FIG. 1 is a longitudinal sectional front view of the furnace, and FIG. 2 is a sectional view of the same side. 1 in the drawing shows the furnace;
6 is a radiant tube, 8 is a nitrogen and oxygen separation and purification device, 10 is a nitrogen supply system, 13 is an oxygen supply system, 14 is an atmosphere sensor, and 17 is a hydrocarbon supply system.

Claims (1)

[Claims] 1. Nitrogen gas and oxygen gas in the atmosphere are separated and purified, and the nitrogen gas is fed into the furnace as a heating furnace or protective atmosphere gas, and the separated oxygen gas is supplied to a heating burner to be used as a single combustion air. An atmosphere heating furnace characterized by mixing and burning. 2. Separate and refine nitrogen gas and oxygen gas in the atmosphere, and throw the nitrogen gas into the furnace as a protective atmosphere gas for the furnace. Dew point of (c) 1. 7 of carbon dioxide or oxygen amount
1. An atmosphere heating system characterized in that a sacrificial sensor for detecting m or two or more types and a hydrocarbon particle gas supply system for preventing oxidation and decarburization of a material to be treated are arranged in the furnace. , .