TWI641432B - Temperature control method of heating furnace for planning downtime - Google Patents

Abstract

A temperature control method for a furnace for planning shutdown includes three preparation steps before the start of the planned shutdown, wherein the first step is to cool the preheating zone, the second step is to cool the first heating zone, and the third step is Cooling in the soaking zone. By reducing the set temperature of the preheating zone, the first heating zone and the soaking zone, the fuel demand is reduced to achieve energy saving.

Description

Temperature control method for heating furnace for planned shutdown

The present invention relates to a temperature control method for a heating furnace, and more particularly to a temperature control method for a furnace for planning shutdown in a planned shutdown of a heating furnace in a hot rolling mill.

Before the production of rolling mill, the hot-rolled steel mill first feeds the flat steel into the heating furnace and heats it up. It enters the preheating zone of the heating furnace and moves through the moving beam in the heating furnace step by step to the heating zone and the soaking zone. The target temperature of the tapping (hereinafter referred to as the tapping temperature) varies depending on the thickness of the steel and the product. In the temperature control, the heating furnace tries to get every steel piece to be discharged to reach the required temperature. The furnace control computer is based on the production schedule, monitoring the position of the steel embryo, moving rate, the target temperature of the furnace, and temperature adjustment. However, during the heating process, the hot rolling mill production has irregular production suspensions, which are divided into two categories, among which the first type of non-planned shutdown: there are periodic replacements such as finishing rolls several times a day, each time. From about 8 minutes to 10 minutes, there is a delay in the processing time due to abnormal production of the production, electronic control abnormalities or mechanical equipment failure. In addition, the second type of planned downtime: there are predictive suspension of programmatic work such as roughing roll replacement and back roll replacement for more than 30 minutes, or temporary equipment failures with planned maintenance and longer downtime plans. At this time, the steel furnace is fully loaded with the steel embryo, and the heating can not be stopped, and must be maintained. As long as the pause state is released, the steel embryo can be immediately produced.

The program control system of the conventional program stops the planned shutdown of the heating furnace, which mainly allows the factory to temporarily reduce the consumption of unnecessary energy (fuel) during the production stoppage, and at the end of the planned downtime, the factory can resume normal production immediately. The pre-planned shutdown and cooling strategy is to reduce the consumption of unnecessary energy (fuel) before starting the planned shutdown. First, let the preheating zone cool down in advance, and then let the first heating zone and the soaking zone cool down earlier. It is the actual start of the planned shutdown of the furnace after the specified steel is reached.

However, the conventional furnace shutdown schedule may change. After the pre-input and start of the specified steel embryo enters the control range of the pre-planned shutdown cooling strategy, the set temperature of the furnace control zone will be reduced to reduce unnecessary Energy (fuel) consumption. If the planned stoppage plan change must be postponed, the change plan information is too slow, and the steel embryo may have insufficient heating temperature due to too early temperature drop, which may result in the factory not being able to produce smoothly.

Therefore, it is necessary to provide an improved temperature control method for a furnace for a planned shutdown to solve the problems of the prior art described above.

The object of the present invention is to provide a temperature control method for a furnace for planning shutdown, which reduces and suspends the heating demand of the steel preform in the preheating zone, the first heating zone and the soaking zone in advance, so that the preheating zone, The set temperature of the first heating zone and the soaking zone is lowered, and the fuel demand is automatically reduced to achieve energy saving.

In order to achieve the above object, the present invention provides a temperature control method for a furnace for planning shutdown, comprising a pre-cooling step, a preheating zone cooling step, a first heating zone cooling step, and a soaking zone cooling step. The step of cooling before is to divide at least one heating furnace into a preheating zone, a first heating zone and a soaking zone, wherein a plurality of steel embryos enter the pre-block by block first. The hot zone is preheated, and then sent to the first heating zone to heat up, and then the steel is transferred to the soaking zone for temperature adjustment to reach a desired tapping temperature.

The preheating zone cooling step, the first heating zone cooling step and the soaking zone cooling step are three preparation steps, and the three preparation steps are gradually performed according to the steel embryo selected to start the planned shutdown, and the selected steel is selected. The embryo leaves the preheating zone and immediately begins to lower the set temperature of the preheating zone by reducing the rate of movement of the steel embryo in the preheating zone to 0%, and immediately after the selected steel embryo leaves the heating zone, the heating zone is set. Temperature, the moving rate of the steel embryo in the heating zone is reduced to 0%, and the selected steel embryo moves to the Nth block of the soaking zone exit. The soaking zone immediately begins to lower the set temperature of the soaking zone, and the moving rate of the steel in the soaking zone decreases. 0%

In addition, the preheating zone cooling step detects the position of the steel preforms in the preheating zone, and when a selected steel blank leaves the preheating zone, the preheating zone is immediately cooled to a preheating zone set temperature, so that The warming movement rate of a preheating zone of the steel embryos in the preheating zone is reduced to 0%; the first heating zone cooling step is to detect the position of the steel embryos in the first heating zone, when one is selected The steel embryo leaves the first heating zone, and the first heating zone is immediately cooled to a first heating zone set temperature, so that the heating rate of a first heating zone of the steel preforms in the first heating zone is reduced to 0%. The soaking step of the soaking zone detects the position of the steel embryos in the soaking zone. When the Nth steel embryo of a selected steel embryo leaves the soaking zone, the soaking zone immediately cools down to an average The hot zone sets the temperature such that the rate of temperature rise of a soaking zone of the steel embryos in the soaking zone is reduced to 0%, where N is an integer.

In an embodiment of the invention, the preheating zone set temperature of the preheating zone is 940 °C.

In an embodiment of the invention, the first heating zone of the first heating zone is set to a temperature of 1200 °C.

In an embodiment of the invention, the soaking zone set temperature of the soaking zone is 1200 °C.

In an embodiment of the present invention, in the pre-cooling step, the heating furnace further distinguishes a second heating zone, the second heating zone is located between the first heating zone and the soaking zone, and the temperature control method Further comprising a second heating zone cooling step, the second heating zone cooling step is to detect the position of the steel embryos in the second heating zone after the first heating zone cooling step, when a selected steel embryo leaves In the second heating zone, the second heating zone is immediately cooled to a second heating zone set temperature, so that the heating rate of the second heating zone of the steel preforms in the second heating zone is reduced to 0%.

In an embodiment of the invention, the second heating zone of the second heating zone is set to a temperature of 1200 °C.

In an embodiment of the present invention, in the soaking step of the soaking zone, when the third block of the selected steel embryo leaves the soaking zone, the soaking zone is immediately cooled to the set temperature of the soaking zone. .

In an embodiment of the present invention, the pre-cooling step further has a setting step of selecting one of the plurality of heating furnaces for cooling, and selecting the selected steel embryo according to the number of the plurality of steel blanks.

In one embodiment of the invention, the furnace is shut down for a period of from 0.5 hours to 4 hours.

As described above, through the temperature control method of the furnace for the planned shutdown, it is known that the steel embryo which will start the planned suspension of production may be scheduled to be in 30 minutes, 1 hour, 2 hours or 3 hours. The procedure that occurs, preheating the zone, the first heating zone, and the soaking zone The steel embryo heating heating demand is reduced and suspended, the set temperature of the preheating zone, the first heating zone and the soaking zone is lowered, and the fuel demand is automatically reduced to achieve energy saving.

101‧‧‧Preheating zone

102‧‧‧First heating zone

102’‧‧‧second heating zone

103‧‧‧Hot zone

S201‧‧‧Pre-cooling steps

S202‧‧‧Setting steps

S203‧‧‧Preheating zone cooling step

S204‧‧‧First heating zone cooling step

S204’‧‧‧First heating zone cooling step

S205‧‧‧Hot zone cooling step

1 is a flow chart of a preferred embodiment of a temperature control method for a furnace for a planned shutdown according to the present invention; and FIG. 2 is a temperature control of a furnace for a planned shutdown according to the present invention. A schematic view of a furnace zone of a preferred embodiment of the method; Figures 3 and 4 are schematic illustrations of an operating system in accordance with a temperature control method for a furnace for a planned shutdown; Figure 5 is for use in accordance with the present invention A flow chart of another preferred embodiment of a temperature control method for a furnace for planning shutdown; and FIG. 6 is another preferred embodiment of a temperature control method for a furnace for planning shutdown according to the present invention A schematic view of the furnace area of the example.

The above and other objects, features and advantages of the present invention will become more <RTIgt; Furthermore, the directional terms mentioned in the present invention, such as upper, lower, top, bottom, front, rear, left, right, inner, outer, side, surrounding, central, horizontal, horizontal, vertical, longitudinal, axial, Radial, uppermost or lowermost, etc., only refer to the direction of the additional schema. Therefore, the directional terminology used is for the purpose of illustration and understanding of the invention.

1 is a preferred embodiment of a temperature control method for a furnace for a planned shutdown, the temperature control method includes a pre-cooling step S201, a setting step S202, and a preheating zone cooling. Step S203, a first heating zone cooling step S204 and a soaking zone cooling step S205. The operation steps and operational principles of the various elements will be described in detail below.

As shown in FIGS. 1 and 2, in the step S201 before the temperature reduction, the pre-cooling step S201 divides at least one heating furnace into a preheating zone 101, a first heating zone 102 and a soaking zone 103, wherein A plurality of steel blanks (not shown) will enter the preheating zone 101 block by block, and then preheated in the preheating zone 101, and then sent to the first heating zone 102 to heat up, and then the steel embryos are transported to the average The hot zone 103 is temperature adjusted to achieve the desired exit temperature, for example between 1159 and 1250 degrees.

Continuing with the first and second figures and in conjunction with FIG. 3, in the setting step S202, the operation is performed by the program-based shutdown operating system as shown in FIG. 3, and one of the plurality of heating furnaces (stop number) is selected. (or more than two) heating furnaces are used to cool down, and the selected steel preforms are selected according to the number (starting ID) of the plurality of steel blanks displayed in the selected heating furnace (starting furnace number), for example: start ID 168851500 . In the present embodiment, the program-based shutdown operating system is operated such that the planned shutdown time of the furnace is from 0.5 hours to 4 hours.

Continuing in Figures 1 and 2, in the preheating zone cooling step S203, the position of the steel preforms in the preheating zone 101 is detected, and when the selected steel blank leaves the preheating zone 101, the preheating The zone is immediately cooled to a preheat zone set temperature range of 0%, for example between 940 °C and 1098 °C (as shown in Figure 4). In this embodiment, the minimum value of the preheating zone set temperature of the preheating zone is 940 °C.

1 and 2, in the first heating zone cooling step S204, the positions of the steel embryos in the first heating zone 102 are detected, and when the selected steel blank leaves the first heating zone 102, The first heating zone 102 is immediately cooled down to a first heating zone set temperature range of 0% speed. For example, between 1200 ° C and 1293 ° C; in this embodiment, the first heating zone of the first heating zone has a minimum set temperature of 1200 ° C.

Continuing with the first and second graphs, in the soaking zone cooling step S205, the positions of the steel embryos in the soaking zone 103 are detected, when the selected steel embryo position is in the Nth position of the baked steel preform. The soaking zone 103 immediately has a temperature decreasing range of 0% of the soaking zone set temperature range, for example, between 1200 ° C and 1288 ° C. In the present embodiment, the soaking zone set temperature of the soaking zone is 1200 ° C.

With the above design, the program shutdown operating system is turned on to operate, and then, as shown in Figure 3, select the start number, select the start ID (from all the steels in the selected furnace), select the down time (stop The time is at least 30 minutes), choose the reason for the shutdown, select the furnace number, single option ALL (all furnaces) or individual furnaces. When ALL is selected, the IDs of other furnaces will be automatically selected according to the starting ID order, for example, start 2 No. furnace and ID 1688515, followed by furnace No. 3 furnace ID 1688516, No. 4 furnace ID 1688517, No. 1 furnace ID 1688518, and began to check the moving position of these IDs. Then, the cooling step of the preheating zone 101, the first heating zone 102 and the soaking zone 103 is performed, wherein each heating furnace detects itself and checks whether the selected steels have left the preheating zone 101 and the first heating zone in sequence. 102 and the soaking zone 103, which in turn generates different pre-cooling operation executions, so that the steel plate moving rate of the warming steel in the designated preheating zone 101, the first heating zone 102 and the soaking zone 103 is specified to be reduced to 0%. The maximum SP/min SP (Set Point set temperature) of the preheating zone 101, the first heating zone 102, and the soaking zone 103 are immediately lowered, and the preheating zone 101, the first heating zone 102, and the soaking zone are simultaneously allowed. All steel embryos in 103 are expected to have a lower temperature at the location where they are, and the temperature of the modulation changes from increasing to decreasing.

As described above, by the temperature control method of the furnace for the planned shutdown, the individual heating furnace or all the heating furnaces are designated by the planned shutdown operating system, and the pre-transmission is performed. Into the start of the planned shutdown of the steel embryo, the program control system automatically monitors the pre-cooling, without having to wait until the start of the planned shutdown of the steel embryo to reach the location of the furnace to cool down, that is, using the steel that is known to start planning to suspend production. The embryo, which may be scheduled to occur after 30 minutes, 1 hour, 2 hours, or 3 hours, reduces the need for heating and heating of the steel preform in the preheating zone 101, the first heating zone 102, and the soaking zone 103 in advance. The set temperature of the preheating zone 101, the first heating zone 102 and the soaking zone 103 is lowered, and the fuel demand is automatically reduced to achieve energy saving.

Please refer to FIGS. 5 and 6 for another preferred embodiment of the method for controlling the temperature of the furnace for the planned shutdown, except that in the step S201 before the temperature reduction, the furnace is further differentiated. a second heating zone 102', the second heating zone 102' is located between the first heating zone 102 and the soaking zone 103. In addition, the temperature control method further includes a second heating zone cooling step S204', The second heating zone cooling step S204' detects the position of the steel embryos in the second heating zone 102' after the first heating zone cooling step S204, when the selected steel blank leaves the second heating zone 102' The second heating zone 102' is cooled to a second heating zone set temperature, for example, between 1200 ° C and 1293 ° C, so that a second heating zone of the steel preforms in the second heating zone 102' is heated and moved. The rate drops to the lowest value in the range of 0%.

As described above, through the temperature control method of the furnace for the planned shutdown, it is known that the steel embryo which will start the planned suspension of production may be scheduled to be in 30 minutes, 1 hour, 2 hours or 3 hours. The process of generating, preheating and suspending the heating demand of the steel preform in the preheating zone 101, the first heating zone 102, the second heating zone 102' and the soaking zone 103, and letting the preheating zone 101 and the first heating zone 102. The set temperature of the second heating zone 102' and the soaking zone 103 is lowered, and the fuel demand is automatically reduced to achieve energy saving.

The present invention has been disclosed in its preferred embodiments, and is not intended to limit the invention, and the present invention may be modified and modified without departing from the spirit and scope of the invention. The scope of protection is subject to the definition of the scope of the patent application.

Claims (9)

A temperature control method for a furnace for planning shutdown, implemented in conjunction with a planned shutdown, and performed before a planned shutdown begins, the temperature control method comprising: a pre-cooling step, at least one The heating furnace is divided into a preheating zone, a first heating zone and a soaking zone, wherein a plurality of steel slabs are moved one by one from an inlet of the preheating zone of the heating furnace, and then preheated in the preheating zone, and then Delivered to the first heating zone to heat up, and then the steel embryos are sent to the soaking zone for temperature adjustment to reach a desired exit temperature; a preheating zone cooling step to detect the preheating of the steel preforms The position of the zone, when a selected steel embryo leaves the preheating zone, the preheating zone is immediately cooled to a preheating zone set temperature, so that the warming rate of a preheating zone of the steel embryos in the preheating zone is lowered. 0%; a first heating zone cooling step, detecting the position of the steel embryos in the first heating zone, when a selected steel embryo leaves the first heating zone, the first heating zone immediately cools to a first a heating zone setting temperature to enable the first heating zone The temperature rise movement rate of a first heating zone of the steel blank is reduced to 0%; a soaking step of the soaking zone detects the position of the steel embryos in the soaking zone, when the Nth steel embryo of a selected steel embryo leaves In the soaking zone, the soaking zone is immediately cooled to a set temperature of the soaking zone, so that the rate of temperature rise and movement of a soaking zone of the steel embryos in the soaking zone is reduced to 0%, wherein N is an integer. The temperature control method according to claim 1, wherein the preheating zone set temperature of the preheating zone is 940 °C. The temperature control method according to claim 1, wherein the first heating zone of the first heating zone has a set temperature of 1200 °C. The temperature control method according to claim 1, wherein the soaking zone has a soaking zone set temperature of 1200 °C. The temperature control method according to claim 1, wherein in the pre-cooling step, the heating furnace further distinguishes a second heating zone, wherein the second heating zone is located in the first heating zone and the soaking zone. In addition, the temperature control method further includes a second heating zone cooling step, the second heating zone cooling step is to detect the position of the steel embryos in the second heating zone after the first heating zone cooling step a selected steel blank exits the second heating zone, and the second heating zone is immediately cooled to a second heating zone set temperature, so that a second heating zone of the steel preforms in the second heating zone has a lowering rate of movement It is 0%. The temperature control method according to claim 5, wherein the second heating zone of the second heating zone is set to a temperature of 1200 °C. The temperature control method according to claim 1, wherein in the soaking step of the soaking zone, when the third steel piece from the selected steel embryo leaves the soaking zone, the soaking zone immediately cools down Set the temperature to the soaking zone. The temperature control method according to claim 1, wherein the pre-cooling step further has a setting step, selecting one heating furnace to cool down among the plurality of heating furnaces, and selecting the quilt according to the number of the plurality of steel embryos The steel embryo is selected. The temperature control method according to claim 1, wherein the furnace has a planned shutdown time of 0.5 hours to 4 hours.