A pulse cycle temperature control method for annealing furnace burner of hot-rolled stainless steel annealing and pickling unit

Abstract

The invention discloses a pulse cycle temperature control method for annealing furnace burners of hot-rolled stainless steel annealing and pickling unit, comprising the following steps: step 1, initializing the start command and actual burning time of each burner, n is the number of the burner, k is the target number of the start burner, and during initialization, n=0, k=0; step 2, the nth to n+k-1th burners are sequentially subjected to single burner cycle control, when n+k-1>m, the nth to mth and the 1st to n+k-1-mth burners are sequentially subjected to single burner cycle control, each burner is independently timed, and the single burner starts the cycle logic, and when n=0 and k=0, step 2 is skipped to enter step 3; step 3, the number of burners to be started is calculated according to the load rate setting value, as the target number k, if the nth burner stops, n is updated to n+1, and the cycle result is that the feedback temperature is close to the set temperature, and the actual load rate is stabilized at the load rate setting value. The method makes the temperature distribution in the region more uniform and saves energy consumption.

Description

Technical Field

[0001] The invention relates to the technical field of annealing furnaces for hot-rolled stainless steel processing lines, and in particular to a pulse circulation temperature control system method for a burner of an annealing furnace of a hot-rolled stainless steel annealing and pickling unit. Background Art

[0002] Annealing furnace plays a very important role in the steel industry. Hot-rolled stainless steel annealing and pickling units are widely used in China. Annealing furnace is an important part of hot-rolled stainless steel annealing and pickling units. At present, the temperature control system of the annealing furnace of hot-rolled stainless steel annealing and pickling units mainly adopts double cross limit control.

[0003] The double cross-limiting temperature control method is relatively stable at high temperatures, but at low temperatures, the burners in the same area will not be fully open, making it difficult to control the temperature. In addition, it is difficult to ensure uniform heating in the furnace by manually heating the burners at a single point during the oven baking process. Summary of the invention

[0004] The purpose of the present invention is to provide a pulse cycle temperature control method for the burner of an annealing furnace of a hot-rolled stainless steel annealing and pickling unit in order to address the technical defect that the annealing furnace in the prior art basically adopts manual control to start and stop the burner.

[0005] The technical solution adopted to achieve the purpose of the present invention is:

[0006] A pulse cycle temperature control method for a burner of an annealing furnace of a hot-rolled stainless steel annealing and pickling unit, wherein the pulse cycle temperature control method controls m burners in a region of a heating section of the annealing furnace, wherein the burners in the region are evenly distributed from the first to the mth burners, and the pulse cycle temperature control method comprises the following steps:

[0007] Step 1, initialize the start command of each burner and the actual combustion time, n is the burner number, k is the target number of the start burners, during initialization, n = 0, k = 0;

[0008] Step 2, the No. 1 to No. m burners perform the following single burner cycle control in sequence, each burner is timed independently, and the single burner starts the cycle logic. When n=0 and k=0, skip step 2 and go to step 3:

[0009] The logic of the single burner start cycle is as follows:

[0010] Step s1, first determine whether the actual burning time of the current burner is 0, if it is 0, jump to step s2, if not 0, then compare the actual burning time of the current burner with the burner opening time, the specific comparison criteria are as follows:

[0011] When the load rate setting value is less than the load rate of all burners turned on, the actual burning time of the burner is compared with the burner opening time; if the comparison result is greater than or equal to, the actual burning time of the burner is reset and the burner is turned off; if the comparison result is less than, the actual burning time of the burner is increased and the burner continues to be turned on;

[0012] Step s2, judging whether the number of cycles of the start-up cycle of a single burner exceeds m, if not, looping to step s1 to start judging the next burner, if exceeded, jumping out of the loop and proceeding to step 3;

[0013] Step 3, according to the load rate setting value, the number of burners to be started is calculated as the target number k. If the nth burner stops, n is updated to n+1. When n exceeds the maximum number of burners m in this area, n=1, and then step 4 is performed. If the nth burner does not stop, the process loops to step 2.

[0014] Step 4, taking the burners No. n to No. n+k-1 in the area as target burners, when n+k-1>m, taking the burners No. n to No. m and No. 1 to No. n+k-1-m as target burners; setting the actual combustion time of the target burners to 1, setting the actual combustion time of other burners to 0, and looping to step 2;

[0015] The result of the cycle is that the feedback temperature is close to the set temperature, and the actual load rate is stable at the load rate set value.

[0016] In the above technical solution, the load rate of all burners opened is 92-97%, preferably 95%.

[0017] In the above technical solution, if the load rate setting value is less than 1-the load rate at which all burners are turned on, all burners are turned off; if the load rate setting value is greater than the load rate at which all burners are turned on, all burners are turned on.

[0018] In the above technical solution, the control system based on the method includes a main controller, a remote IO controller, and a host computer, wherein: the host computer is communicatively connected to the main controller, the main controller is connected to the burner controller through the remote IO controller, and the burner controller controls the start and stop of the burner.

[0019] In the above technical solution, the thermocouple collects the temperature of the local area as the feedback temperature, and the thermocouple transmits the data to the temperature regulator in the main controller. The temperature of the local area is set as the set temperature on the host computer, and the load rate setting value is determined by the feedback temperature and the set temperature.

[0020] In the above technical solution, the load rate setting value and the load rate of all burners turned on are manually input on the host computer, or the load rate setting value is output by the temperature regulator.

[0021] In the above technical solution, the main controller uses S7-1500 series CPU, uses TIA Portal V17 to develop the program, the remote IO controller uses ET200SP series remote module, the remote IO controller connects N burner controller signals, and each burner controller controls the start and stop of a burner.

[0022] In the above technical solution, the S7-1500 series CPU and the remote IO controller communicate via Profinet, the remote IO controller and the burner controller are connected via a hard line, and the host computer and the main controller communicate via Ethernet.

[0023] In the above technical solution, the shortest combustion cycle = minimum combustion time + combustion timeout time, wherein the minimum combustion time and the combustion timeout time are both set manually;

[0024] Pulse switching point load rate = minimum combustion time * maximum load rate / shortest combustion cycle;

[0025] Burner closing time = minimum burning time * maximum load rate / load rate setting value - minimum burning time;

[0026] When the load rate setting value is less than 1-the load rate of all burners turned on, the burner closing time = the minimum burning time;

[0027] Burner opening time = combustion timeout time * load rate setting value / (maximum load rate - load rate setting value);

[0028] When the load rate setting value > the pulse switching point load rate, the burner opening time = minimum burning time;

[0029] In the above technical solution, the maximum load rate is set to 99-101%, preferably 100%.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1. The present invention realizes the pulse cycle start control of the burner of the annealing furnace of the continuous annealing and pickling unit, which greatly improves the degree of electronic control automation of the annealing furnace.

[0032] 2. The burner pulse cycle temperature control system has the advantages of greatly reducing energy consumption, making the furnace heated evenly, and reducing the generation of NOx, providing strong technical support for the construction of the annealing furnace of the continuous annealing and pickling unit in the future.

[0033] 3. The present invention is based on PLC technology and adopts Profinet communication protocol to ensure the stability of the annealing furnace system. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 Shown is a schematic structural diagram of the control system of the present invention.

[0035] Figure 2 Shown is a schematic diagram of temperature PID. DETAILED DESCRIPTION

[0036] The present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0037] Example 1

[0038] A pulse cycle temperature control method for a burner of an annealing furnace of a hot-rolled stainless steel annealing and pickling unit, the method is based on a control system including a main controller, a remote IO controller, and a host computer, wherein:

[0039] In this embodiment, the main controller uses Siemens S7-1500 series CPU, and uses TIA Portal V17 to develop the program. The remote IO controller uses Siemens ET200SP series remote module. The remote IO controller connects N burner controller signals, and each burner controller controls the start and stop of a burner. Profinet communication is used between the Siemens S7-1500 series CPU and the remote IO controller. The remote IO controller and the burner controller are connected by a hard wire. The host computer uses WINCC7.5 software to develop the host computer HMI system, and the host computer and the main controller communicate using Ethernet.

[0040] The cyclic temperature control method controls m burners in a zone in the heating section of the annealing furnace. The burners in the zone are evenly distributed from the first to the mth. The thermocouple collects the temperature of the zone as the feedback temperature. The thermocouple transmits the data to the temperature regulator in the main controller. The temperature of the zone is set as the set temperature on the host computer. The load rate setting value is determined by the feedback temperature and the set temperature. The load rate setting value and the load rate of all burners are manually input on the host computer, or the load rate setting value is output by the temperature regulator.

[0041] The burner opening time, burner closing time and burner cycle time are calculated according to the load rate setting value. The specific calculation method is as follows:

[0042] The shortest combustion cycle = minimum combustion time + combustion timeout time, where the minimum combustion time and combustion timeout time are both set manually;

[0043] Pulse switching point load rate = minimum combustion time * maximum load rate / shortest combustion cycle. The maximum load rate is generally set to 100%, and can also be set according to actual conditions.

[0044] Burner closing time = minimum burning time * maximum load rate / load rate setting value - minimum burning time;

[0045] When the load rate setting value is <5%, the burner closing time = minimum burning time;

[0046] Burner opening time = combustion timeout time * load rate setting value / (maximum load rate - load rate setting value);

[0047] When the load rate setting value > the pulse switching point load rate, the burner opening time = minimum burning time;

[0048] The pulse cycle temperature control method is as follows:

[0049] Step 1, initialize the start command of each burner and the actual combustion time, n is the burner number, k is the target number of the start burners, during initialization, n = 0, k = 0;

[0050] Step 2, the No. 1 to No. m burners perform the following single burner cycle control in sequence, each burner is timed independently, and the single burner starts the cycle logic. When n=0 and k=0, skip step 2 and go to step 3:

[0051] The logic of the single burner start cycle is as follows:

[0052] Step s1, first determine whether the actual burning time of the current burner is 0, if it is 0, jump to step s2, if not 0, then compare the actual burning time of the current burner with the burner opening time, the specific comparison criteria are as follows:

[0053] When the load rate setting value is less than the load rate of all burners turned on, the actual burning time of the burner is compared with the burner opening time; if the comparison result is greater than or equal to, the actual burning time of the burner is reset and the burner is turned off; if the comparison result is less than, the actual burning time of the burner is increased and the burner continues to be turned on;

[0054] Step s2, judging whether the number of cycles of the start-up cycle of a single burner exceeds m, if not, looping to step s1 to start judging the next burner, if exceeded, jumping out of the loop and proceeding to step 3;

[0055] Step 3, according to the load rate setting value, the number of burners to be started is calculated as the target number k. If the nth burner stops, n is updated to n+1. When n exceeds the maximum number of burners m in this area, n=1, and then step 4 is performed. If the nth burner does not stop, the process loops to step 2.

[0056] Step 4, taking the burners No. n to No. n+k-1 in the area as target burners, when n+k-1>m, taking the burners No. n to No. m and No. 1 to No. n+k-1-m as target burners; setting the actual combustion time of the target burners to 1, setting the actual combustion time of other burners to 0, and looping to step 2;

[0057] The result of the cycle is that the feedback temperature is close to the set temperature, and the actual load rate is stable at the load rate set value.

[0058] In the above steps, if the load rate setting value is less than 1-the load rate at which all burners are turned on (95%), all burners are turned off; if the load rate setting value is greater than the load rate at which all burners are turned on (95%), all burners are turned on.

[0059] Example 2

[0060] There are 10 burners in one area of ​​the heating section of the annealing furnace, that is, m=10, which are evenly distributed in the area and are burners No. 1 to No. 10.

[0061] Step 1, during initialization, n=0, k=0;

[0062] Entering step 3, the number of burners to be started is calculated according to the load rate setting value, and the calculated target number k=3;

[0063] Step 4, burners No. 1 to 3 in the area are used as target burners, the actual combustion time of the target burners is set to 1, the actual combustion time of other burners is set to 0, and the process is repeated to step 2;

[0064] Step 2, burners No. 1 to No. 10 perform the following single burner cycle control in sequence, each burner is timed independently, and the single burner starts the cycle logic:

[0065] Step s1, first determine whether the actual combustion time of burner No. 1 is 0, if not 0, then compare the actual combustion time of the burner with the burner opening time, the specific comparison criteria are as follows: when the load rate setting value is less than the load rate of all burners turned on (95%), the actual combustion time of the burner is compared with the burner opening time; if the comparison result is greater than or equal to, the actual combustion time of the burner is reset and the burner is turned off, if the comparison result is less than, the actual combustion time of the burner is increased and the burner continues to be turned on;

[0066] Step s2, at this time, the number of cycles is 1, which does not exceed 10, then the No. 2 burner continues to perform step s1, at this time the number of cycles is 2, which does not exceed 10, then the No. 3 burner continues to perform step s1, at this time the number of cycles is 3, then the No. 4 burner performs step s1, the actual combustion time of the No. 4 burner is 0, the single burner start loop logic is not executed, the number of cycles is +1, and the cycle is repeated in sequence until the number of cycles is 10, and then the burner is jumped out to perform step 3;

[0067] Step 3, if the calculated k is still 3, if the No. 1 burner stops, then update n to 2, the No. 2 to No. 4 burners are the target burners, and the No. 2 to No. 4 burners are sequentially controlled by single burner cycle: if the No. 2 burner stops, then continue to update n to 3, the No. 3 to No. 5 burners are the target burners, and they are updated and sequentially controlled by single burner cycle until n = 9, the No. 9 to No. 10 burners and the No. 1 burner are the target burners;

[0068] The above processes are all based on the situation where k remains unchanged. If the value of k calculated here is 4, then the No. 10, No. 1, No. 2, and No. 3 burners are the target burners.

[0069] Until the cycle result is that the feedback temperature is close to the set temperature and the actual load rate is stable at the load rate set value.

[0070] This method makes the temperature distribution in the area more uniform and saves more energy.

[0071] The above is only a preferred embodiment of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A pulse cycle temperature control method for the burner of an annealing furnace of a hot-rolled stainless steel annealing and pickling unit, characterized in that: The pulse cycle temperature control method controls m burners in a zone in the heating section of the annealing furnace, and the burners in the zone are evenly distributed from the 1st to the mth burners. The pulse cycle temperature control method includes the following steps: Step 1, initialize the start command of each burner and the actual combustion time, n is the burner number, k is the target number of the start burners, during initialization, n=0, k=0; Step 2, the No. 1 to No. m burners perform the following single burner cycle control in sequence, each burner is timed independently, and the single burner starts the cycle logic. When n=0 and k=0, skip step 2 and go to step 3: The logic of the single burner start cycle is as follows: Step s1, first determine whether the actual burning time of the current burner is 0, if it is 0, jump to step s2, if not 0, then compare the actual burning time of the current burner with the burner opening time, the specific comparison criteria are as follows: When the load rate setting value is less than the load rate of all burners turned on, the actual burning time of the burner is compared with the burner opening time; if the comparison result is greater than or equal to, the actual burning time of the burner is reset and the burner is turned off; if the comparison result is less than, the actual burning time of the burner is increased and the burner continues to be turned on; Step s2, judging whether the number of cycles of the single burner start-up cycle has reached m, if not, looping to step s1 to start judging the next burner, if reached, jumping out of the loop and proceeding to step 3; Step 3, calculate the number of burners that need to be started according to the load rate setting value, as the target number k, if the nth burner stops, then update n to n+1, when n exceeds the maximum number of burners m in this area, n=1, and then proceed to step 4, if the nth burner does not stop, loop to step 2; Step 4, taking the burners No. n to No. n+k-1 in the area as target burners, and when n+k-1>m, taking the burners No. n to No. m and No. 1 to No. n+k-1-m as target burners; setting the actual combustion time of the target burners to 1, and the actual combustion time of other burners to 0, and looping to step 2; The result of the cycle is that the feedback temperature is close to the set temperature, and the actual load rate is stable at the load rate set value.

2. The pulse cycle temperature control method for the annealing furnace burner of the hot-rolled stainless steel annealing and pickling unit according to claim 1 is characterized in that: The load rate of all burners is 92-97%.

3. The pulse cycle temperature control method for the annealing furnace burner of the hot-rolled stainless steel annealing and pickling unit according to claim 1, characterized in that: If the load rate setting value is less than 1-the load rate at which all burners are turned on, all burners are turned off. If the load rate setting value is greater than the load rate at which all burners are turned on, all burners are turned on.

4. The pulse cycle temperature control method for the annealing furnace burner of the hot-rolled stainless steel annealing and pickling unit according to claim 1, characterized in that: The control system on which the method is based includes a main controller, a remote IO controller, and a host computer, wherein: the host computer is communicatively connected to the main controller, the main controller is connected to a burner controller via the remote IO controller, and the burner controller controls the start and stop of the burner.

5. The pulse cycle temperature control method for the annealing furnace burner of the hot-rolled stainless steel annealing and pickling unit according to claim 4, characterized in that: The thermocouple collects the temperature of the local area as the feedback temperature, and transmits the data to the temperature regulator in the main controller. The temperature of the local area is set as the set temperature on the host computer, and the load rate setting value is determined by the feedback temperature and the set temperature.

6. The pulse cycle temperature control method for the burner of the annealing furnace of the hot-rolled stainless steel annealing and pickling unit according to claim 5, characterized in that: The load rate setting value and the load rate of all burners turned on are manually input on the host computer, or the load rate setting value is output by the temperature regulator.

7. The pulse cycle temperature control method for the annealing furnace burner of the hot-rolled stainless steel annealing and pickling unit according to claim 4, characterized in that: The main controller uses S7-1500 series CPU and uses TIA Portal V17 to develop the program. The remote IO controller uses ET200SP series remote module. The remote IO controller is connected to N burner controller signals, and each burner controller controls the start and stop of a burner.

8. The pulse cycle temperature control method for the annealing furnace burner of the hot-rolled stainless steel annealing and pickling unit according to claim 4, characterized in that: The S7-1500 series CPU and the remote IO controller communicate via Profinet, the remote IO controller and the burner controller are connected via a hard line, and the host computer and the main controller communicate via Ethernet.

9. The pulse cycle temperature control method for the annealing furnace burner of the hot-rolled stainless steel annealing and pickling unit according to claim 1, characterized in that: The shortest combustion cycle = minimum combustion time + combustion timeout time, where the minimum combustion time and combustion timeout time are set manually; Pulse switching point load rate = minimum combustion time * maximum load rate / shortest combustion cycle; Burner closing time = minimum burning time * maximum load rate / load rate setting value - minimum burning time; When the load rate setting value is less than 1-the load rate of all burners turned on, the burner closing time = the minimum burning time; Burner opening time = combustion timeout time * load rate setting value / (maximum load rate - load rate setting value); When the load rate setting value > pulse switching point load rate, the burner opening time = minimum combustion time.

10. The pulse cycle temperature control method for the burner of the annealing furnace of the hot-rolled stainless steel annealing and pickling unit according to claim 9, characterized in that: The maximum load factor is set at 99-101%.

11. The pulse cycle temperature control method for the annealing furnace burner of the hot-rolled stainless steel annealing and pickling unit according to claim 2, characterized in that: The load factor of all burners is 95%.

12. The pulse cycle temperature control method for the annealing furnace burner of the hot-rolled stainless steel annealing and pickling unit according to claim 10, characterized in that: The maximum load factor is set at 99-100%.

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