JPS61119987A - Method of controlling furnace pressure of continuous type heating furnace - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for controlling the pressure inside a continuous heating furnace in which the amount of combustion gas fluctuates widely.

[Conventional technology]

The pressure in the furnace of a continuous heating furnace is due to the intrusion of the atmosphere through the openings in the furnace body, such as the charging door, extraction door manhole, or opening of the furnace, or the blowing out of the combustion gas inside the furnace, and is a factor in the fuel consumption rate. This is one of the fluctuation factors.

That is, when the pressure inside the furnace is negative, the amount of air entering the furnace increases and the atmospheric temperature inside the furnace decreases.

In order to ensure the heating capacity of the heated material, the amount of fuel burned must be increased.

In addition, when the pressure inside the furnace is positive, the amount of combustion gas blown out of the furnace increases, and just like when the pressure inside the furnace is negative, the amount of fuel burned must be increased to ensure heating capacity. I don't get it.

First, in a continuous heating furnace, as shown in Figure 1,
Detect the pressure Pv in the soaking zone 5, and adjust the opening of the furnace pressure control damper 2 installed in the flue 3 by adjusting the deviation Δε = (pv - SV) so that it reaches the set value SV. It is adjusted so that it becomes 0 by performing this with the device 4. At this time, the set value SV is kept constant.

However, recent heating furnaces have diverse operating conditions, such as the presence of cold pieces and hot pieces, and the amount of combustion gas fluctuates significantly. Furthermore, in order to improve the accuracy of combustion control in each zone, more partition walls 9 are being installed in the furnace, and the pressure loss within the heating furnace is also larger than in the past.

Therefore, as shown in Fig. 2, if the set pressure PVL3 of the soaking zone is kept constant regardless of the amount of combustion gas, the charging port 6
The pressure P ], 4 is expressed by equation (1).

p=pv-∆PF =pv-∆Pa Pressure loss Q in the furnace during PO: amount of combustion gas When the amount of combustion is small [for example, point (a) in Figure 2], the pressure inside the furnace at the charging port 6 becomes positive, and the combustion gas from the charging port 6 When the amount of air is increased and the amount of combustion is large [for example, the second
At point (B) in the figure, the pressure inside the furnace at the charging port 6 becomes negative, and the amount of air entering the furnace is larger than that at the charging port 6.

[Problem to be Solved by the Invention 3] As mentioned above, when the operating conditions of the heating furnace are diverse and the amount of combustion gas fluctuates greatly, the combustion source due to the blowout of combustion gas or the intrusion of air into the heating furnace. There is a problem of unit suffocation and quality deterioration of heated materials.

The object of the present invention is to improve the reduction in combustion intensity and to reduce the quality deterioration of heat-receiving materials.

[Means for solving the problem 2] In the present invention, the furnace pressure setting value in the soaking zone is varied according to the operating conditions of the heating furnace, and the furnace pressure at the heating furnace charging inlet is maintained at the optimum value. , minimize the amount of air entering the heating furnace and the amount of combustion gas blowing out of the furnace.

In other words, in controlling the pressure inside a continuous heating furnace, the amount of fuel gas is calculated by measuring the fuel with an orifice attached to the fuel main pipe, and the calculated value is introduced into a pre-memorized formula to set the set value ( (target value) and set the furnace pressure to this target value.

〔Example〕

FIG. 3 shows an outline of a heating furnace that implements one embodiment of the furnace pressure control of the present invention. In this heating furnace.

The pressure pv in the soaking zone 5 is verified and the deviation Δε= (PV - SV) is adjusted to 0 so that it becomes the set value SV. The set value S■' shown in the following equation (2) was measured, the combustion gas claw was calculated, and the value was stored in advance.
Have them compare.

sv' = ΔPa X (Q/Q2) 2・”(2)
A1≦sv'≦A2 where sv': Setting value in the soaking zone ΔPo: Pressure loss in the furnace at combustion gas amount Qo: Combustion gas A 1 + A2: Allowable minimum and maximum setting values in the furnace Typically, A I =0.5 artmAq, A2 =1.
5-2. OmtmAq is often adopted.

Therefore, as shown in FIG. 4, the furnace pressure P14 at the charging port 6 is expressed by equation (3), P"PV-ΔP P=sV'-AP p==ΔP a
X (Q/Q o )”−ΔP o X (Q/Q
o)”=0...
...(3), the pressure inside the furnace is maintained at OmmAq at the charging port 6 during operation [point (c) in Figure 4], and the amount of air entering from the atmosphere and the amount of IIA sintering gas blown out inside the furnace are reduced. . The pi combustion gas can be measured by directly measuring the amount of combustion gas, or by measuring the air used for burner combustion. *There are ways to calculate.

〔Effect of the invention〕

As is clear from the embodiments described above, since the pressure inside the furnace is controlled according to the fluctuating amount of combustion gas, the pressure inside the furnace at the charging port is Q mmAq, which is the same as the atmosphere, and the amount of incoming air and the combustion inside the furnace are controlled. The amount of gas blown out is kept to a minimum, which has a significant effect on reducing fuel consumption and maintaining the quality of the heated material.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view showing an overview of a heating furnace that uses a conventional furnace pressure control method, and Figure 2 shows the combustion gas amount and charging port furnace in a heating furnace that uses a conventional furnace pressure control method. It is a graph showing the relationship between internal pressure. Fig. 3 is a sectional view showing an outline of a heating furnace that implements one embodiment of the present invention, and Fig. 4 shows the amount of combustion gas and the inside of the charging port in a heating furnace that employs the furnace pressure control method of the present invention. It is a graph showing the relationship between pressures. l: Heating furnace 2: Furnace pressure control damper 3: Flue
4: Damper opening controller 5: Soaking area 6:
Charging port 7: Extraction port 8: M, protrusion 9: Furnace partition wall 10: Burner 11: Fuel main pipe 12 Niorifice 13 Soaking zone setting pressure 14: Charging port furnace pressure

Claims (1)

[Claims] In the furnace pressure control of a continuous heating furnace, the furnace pressure setting in the soaking zone is set to a value calculated by the following formula based on the amount of combustion gas in the entire heating furnace. Furnace pressure control method for heating furnace. SV=ΔPo×(Q/Q_0)^2 A_1≦SV≦A_2 where SV: Setting value for controlling pressure in the furnace ΔP_0: Pressure loss Q in the furnace at combustion gas amount Q_0: Combustion gas amount A_1: Minimum allowable setting value in the furnace A_2: Maximum allowable setting value in the furnace