Method for starting control of exhaust fan coupled with outlet air duct and continuous casting machine

Abstract

The application provides a starting control method of exhaust steam fan with outlet air pipe converging coupling and a continuous casting machine device. The exhaust steam fan is divided into N groups, the i-th group is composed of M i exhaust steam fans, the outlet air pipes of each exhaust steam fan are converging coupled and then exhaust steam through a converging air pipe, N and M i are integers greater than or equal to 1, 1≤i≤N; the exhaust steam fans are started in turn according to the grouping, and in each group, the exhaust steam fans are started in turn according to the sequence, and the first exhaust steam fan is formally started while the remaining exhaust steam fans are micro-started; the method can solve the problem of excessive current caused by simultaneous starting of multiple exhaust steam fans, and can prevent starting failure caused by air flow disturbance during starting in turn, and can be used in a continuous casting machine device to improve the stability and reliability of the device.

Description

Technical Field

[0001] This invention relates to the start-up control of exhaust fans and continuous casting machine equipment in the metallurgical industry, and particularly to the start-up control method of exhaust fans with outlet duct manifold coupling and continuous casting machine equipment. Background Technology

[0002] Exhaust fans are mainly used to discharge steam generated during the production process through pipelines. When the amount of steam generated is large, multiple exhaust fans are usually required for steam extraction and discharge. In conventional designs, each exhaust fan outlet corresponds to a separate duct for steam discharge. However, to simplify pipeline layout and reduce space occupation, the outlet ducts of multiple (i.e., two or more) exhaust fans are combined and coupled to share a common duct for steam discharge.

[0003] For example, in continuous casting equipment, exhaust fans (or steam exhaust fans) are one of the most crucial pieces of equipment in the continuous casting production line. Their main function is to exhaust the steam generated after the high-temperature slabs are cooled by secondary cooling water spray during the continuous casting process, through pipelines, outside the plant. In slab continuous casting, due to the large volume and high heat of the slabs, as well as the large amount of steam generated after cooling, multiple exhaust fans are required for steam extraction and discharge. In conventional designs, each exhaust fan outlet corresponds to a separate duct for steam discharge. However, due to the complex layout of slab continuous casting equipment and pipelines, and the increasing demand for platform space as slab cross-sections become wider and thicker and slabs become more multi-flow, many projects require multiple exhaust fan outlet ducts to be combined and coupled to share a common duct for steam discharge.

[0004] The conventional starting control method for exhaust fans is either manual starting by an operator or automatic starting based on control conditions. Because exhaust fan motors have high power, starting multiple exhaust fans simultaneously can easily cause system overload due to excessive current. If multiple exhaust fans start sequentially, and their outlet ducts are coupled together, the steam flow during startup will cause airflow interference at the duct junction. The interference occurs when the first exhaust fan starts drawing steam from the steam chamber inlet, accelerating it, and then discharging it through the outlet duct. Simultaneously, if other exhaust fans coupled through the outlet duct are not yet started, some of the steam discharged from the already started fans will, under pressure difference, flow backwards into the ducts of the unstarted exhaust fans at the outlet duct junction, creating interfering airflow. This airflow then flows back into the steam chamber, forming a weak internal airflow cycle. This cycle will cause the blades of the unstarted exhaust fans to rotate in the opposite direction due to the interfering airflow, interfering with the start-up control of these fans and causing malfunctions. For example, when the exhaust fan receives a start command, the system may display a stall fault warning, leading to the exhaust fan startup failure.

[0005] Therefore, finding a solution that can both address the problem of excessive current caused by the simultaneous start-up of multiple exhaust fans and prevent start-up failures caused by airflow disturbances during sequential start-up is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] In view of the above-mentioned technical status, the present invention provides a starting control method for exhaust fans with outlet duct manifold coupling. When using this method for starting control, it can solve the problem of excessive current caused by the simultaneous starting of multiple exhaust fans, and can prevent starting failures caused by airflow disturbances when starting sequentially.

[0007] The technical solution provided by this invention is: a start-up control method for an exhaust fan coupled to an outlet duct, wherein the exhaust fan is divided into N groups, where N is an integer greater than or equal to 1;

[0008] The i-th group consists of M i The system consists of several exhaust fans. The outlet ducts of each exhaust fan are coupled together and then discharge steam through a connecting duct, denoted as the i-th connecting duct. M i Let i be an integer greater than or equal to 1, where 1 ≤ i ≤ N;

[0009] The j-th exhaust fan in the i-th group is denoted as exhaust fan ij, 1≤j≤M i ;

[0010] The startup control method includes the following steps:

[0011] (1) Let i = 1;

[0012] (2) The starting methods for each exhaust fan in group i are as follows:

[0013] The initial speed v of each exhaust fan in group i 初始ij same;

[0014] Let j = 1; start the exhaust fan ij according to method A. At the same time, except for the j-th exhaust fan in the i-th group, the other exhaust fans are micro-started according to method B.

[0015] (3) When the start-up cycle of the exhaust fan ij is completed, proceed to step (4);

[0016] (4) Let j = j + 1, and start the exhaust fan ij according to method C;

[0017] (5) Repeat step (4) until j = M i ;

[0018] (6) Let i=i+1;

[0019] (7) Repeat steps (2) to (6) until i = N.

[0020] Method A is the formal start-up method for the exhaust fan ij, as detailed below:

[0021] The initial speed of the exhaust fan ij is v 初始ij ;like Figure 1 As shown, exhaust fan ij officially starts, the speed of exhaust fan ij increases, and the start-up and operation time t of exhaust fan ij is... 微ij The speed then reaches a very low speed V. 微ij Startup target time t 目标ij After reaching the target speed v 目标ij , t 目标ij >t 微 ij, then maintain the target speed v 目标ij Continue running t 间隔ij (denoted as interval time t) 间隔ij The start-up cycle of the exhaust fan ij is completed, and the target speed v is maintained thereafter. 目标ij run;

[0022] Method B is a micro-starting method for the exhaust fan ij, as detailed below:

[0023] The initial speed of the exhaust fan ij is v 初始ij ;like Figure 2 As shown, exhaust fan ij begins a micro-start, the speed of exhaust fan ij increases, and the micro-starting time t... 微ij The speed then reaches a very low speed V. 微ij Then maintain a low rotation speed V 微ij Running, waiting to enter the formal startup;

[0024] Method C is the formal start-up method for the exhaust fan ij from the micro-start state, as detailed below:

[0025] like Figure 3 As shown, the exhaust fan ij officially starts from the micro-start state, and the speed of the exhaust fan ij starts from the micro-speed V. 微ij Start increasing, officially start running target time t 目标ij After reaching the target speed v 目标ij Then maintain the target speed v 目标ij Continue running t 间隔ij (denoted as interval time t) 间隔ij The start-up cycle of the exhaust fan ij is completed, and the target speed v is maintained thereafter. 目标ij run.

[0026] Preferably, in step (2), the initial rotational speed v of each exhaust fan in the i-th group is... 初始ij =0.

[0027] In method A, preferably, at least one of the following conditions (a) to (v) is satisfied:

[0028] (i) The time t of each row of blowers ij in the i-th group 微ij same;

[0029] (ii) The micro-speed V of each row of steam blowers ij in group i 微ij same;

[0030] (III) The target time t for each row of steam blowers ij in the i-th group 目标ij same;

[0031] (iv) The target rotational speed v of each steam blower ij in group i 目标ij same;

[0032] (v) The interval t between each row of steam blowers ij in the i-th group 间隔ij same.

[0033] In method B, preferably, at least one of the following conditions (a) to (v) is satisfied:

[0034] (i) The time t of each row of blowers ij in the i-th group 微ij same;

[0035] (ii) The micro-speed V of each row of steam blowers ij in group i 微ij same.

[0036] In method C, preferably, at least one of the following conditions (a) to (v) is satisfied:

[0037] (i) The micro-speed V of each row of steam blowers ij in group i 微ij same;

[0038] (ii) The target time t for each row of steam blowers ij in the i-th group 目标ij same;

[0039] (III) The target rotational speed v of each steam blower ij in group i 目标ij same;

[0040] (iv) The interval t between each row of steam blowers ij in the i-th group 间隔ij same.

[0041] In this invention, the micro-speed V of the exhaust fan ij 微ij The setting standard is to be able to overcome airflow disturbances during rotation, that is, at this micro-speed V 微ij Under certain conditions, the exhaust fan ij does not rotate freely with the disturbing airflow, thus avoiding startup failure when the exhaust fan ij is officially started.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] (1) In this invention, the exhaust fans are started in the order of grouping, which can reduce the overall start-up load and reduce the system load failure rate;

[0044] (2) In this invention, in each group, the exhaust fans are started in sequence to further reduce system load failure; and, in each group, an anti-disturbance control scheme is set, that is, when the first exhaust fan in the group is started, the remaining exhaust fans are set to a micro speed for micro-start, which can effectively avoid the start failure caused by the airflow disturbance caused by the duct coupling, which causes the subsequent exhaust fans to rotate freely with the disturbing airflow, and can also ensure that the system load does not change suddenly under the micro speed condition;

[0045] (3) The control method of the present invention is applicable to the start-up of exhaust fans with pipeline manifold coupling. For example, in the metallurgical industry, when the continuous casting machine equipment includes exhaust fans with pipeline manifold coupling, the start-up control method of the present invention can improve the stability and reliability of the equipment. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of the formal start-up of the exhaust fan ij in this invention.

[0047] Figure 2 This is a schematic diagram of the micro-start of the exhaust fan ij in this invention.

[0048] Figure 3 This is a schematic diagram of the formal start-up of the exhaust fan ij from the micro-start state in this invention.

[0049] Figure 4 This is a schematic diagram of the exhaust fan start-up control when two groups of four exhaust fans are coupled together to form the outlet duct. Detailed Implementation

[0050] The present invention will be further described in detail below with reference to the embodiments. It should be noted that the embodiments described below are intended to facilitate the understanding of the present invention. Non-essential improvements and adjustments made to the present invention by those skilled in the art based on the above description of the present invention are still within the protection scope of the present invention.

[0051] In this invention, the terms "including" and "comprising" should be interpreted as including rather than exclusive or exhaustive; that is, they mean "including but not limited to".

[0052] In this invention, terms such as "first" and "second" are used to describe the purpose and should not be construed as indicating or implying relative importance.

[0053] In this invention, "multiple units" means two or more units.

[0054] In this embodiment of the invention, the exhaust fans coupled to the outlet duct are divided into N groups, where N is an integer greater than or equal to 1. The i-th group consists of M... i It consists of a steam exhaust fan, 1≤i≤N, M i The value is an integer greater than or equal to 1. In the i-th group, the outlet ducts of each exhaust fan are coupled together and then discharge steam through a single duct. There are N groups corresponding to N ducts, and the duct in the i-th group is denoted as the i-th duct.

[0055] In the exhaust fans coupled to the outlet duct, the j-th exhaust fan in the i-th group is denoted as exhaust fan ij, where 1≤j≤M. i .

[0056] For example, in some embodiments, the exhaust fans in the outlet duct manifold coupling are divided into two groups. The first group consists of three exhaust fans, whose outlet ducts are coupled together and then discharge steam through a single manifold, denoted as the first manifold. The second group consists of four exhaust fans, whose outlet ducts are coupled together and then discharge steam through a single manifold, denoted as the second manifold. The three exhaust fans in the first group are designated as exhaust fans 11, 12, and 13; the four exhaust fans in the second group are designated as exhaust fans 21, 22, 23, and 24.

[0057] For example, in some embodiments, the exhaust fans of the outlet duct junction coupling are divided into two groups. The first group consists of three exhaust fans, and the steam is discharged through a junction duct after the outlet ducts of the three exhaust fans are junction coupled. The second group consists of one exhaust fan. The three exhaust fans in the first group are designated as exhaust fans 11, 12, and 13, respectively; the one exhaust fan in the second group is designated as exhaust fan 21.

[0058] The starting methods for the exhaust fan ij include formal start, micro start, and formal start from micro start state, which are respectively performed using the following methods A, B, and C.

[0059] Method A: Formal start-up of exhaust fan ij

[0060] like Figure 1 As shown, the initial rotational speed of the exhaust fan ij is v. 初始ij The exhaust fan ij officially starts, the speed of the exhaust fan ij increases, and the start-up and operation time of the exhaust fan ij is t. 微ij The speed then reaches a very low speed V. 微ij Startup target time t 目标ij After reaching the target speed v 目标ij , t 目标ij >t 微ij, then maintain the target speed v 目标ij Continue running t 间隔ij (denoted as interval time t) 间隔ij The start-up cycle of the exhaust fan ij is completed, and the target speed v is maintained thereafter. 目标ij run.

[0061] Method B: Micro-start of exhaust fan ij

[0062] like Figure 2 As shown, the initial rotational speed of the exhaust fan ij is v. 初始ij The exhaust fan ij begins a micro-start, the speed of the exhaust fan ij increases, and the micro-starting time t... 微ij The speed then reaches a very low speed V. 微 ij, then maintain a low rotation speed V 微ij Running, waiting to enter the formal startup.

[0063] Method C: Formal start-up of the exhaust fan ij from the micro-start state.

[0064] like Figure 3 As shown, the exhaust fan ij officially starts from the micro-start state, and the speed of the exhaust fan ij starts from the micro-speed V. 微ij Start increasing, officially start running target time t 目标ij After reaching the target speed v 目标ij Then maintain the target speed v 目标ij Continue running t 间隔ij (denoted as interval time t) 间隔ij The start-up cycle of the exhaust fan ij is completed, and the target speed v is maintained thereafter. 目标ij run.

[0065] In this embodiment, the starter control method for the exhaust fans coupled to the outlet duct is as follows: they are started sequentially in groups; and within each group, they are started sequentially, with the first exhaust fan starting while the remaining exhaust fans are micro-started. Specifically, the steps are as follows:

[0066] (1) Let i = 1;

[0067] (2) The starting methods for each exhaust fan in group i are as follows:

[0068] The initial speed v of each exhaust fan in group i 初始ij same;

[0069] Let j = 1; start the exhaust fan ij according to method A. At the same time, except for the j-th exhaust fan in the i-th group, the other exhaust fans are micro-started according to method B.

[0070] (3) When the start-up cycle of the exhaust fan ij is completed, proceed to step (4);

[0071] (4) Let j = j + 1, and start the exhaust fan ij according to method C;

[0072] (5) Repeat step (4) until j = M i ;

[0073] (6) Let i=i+1;

[0074] (7) Repeat steps (2) to (6) until i = N, at which point the exhaust fan of the outlet duct coupling is finished starting.

[0075] For example, in some embodiments, the following conditions are met:

[0076] In step (2), the time when the first exhaust fan in the first group, namely exhaust fan 11, is officially started is denoted as t0, and t0 = 0; the initial speed v of each exhaust fan in the i-th group is... 初始ij The same, denoted as v0;

[0077] In method A, the micro-speed V of each exhaust fan ij in the i-th group 微ij The same, denoted as v1; target rotational speed v 目标ij Same, denoted as v2; target time t 目标ij The same, denoted as t1; the interval time t 间隔ij The same, denoted as t2; and t1=25s, t2=5s, v0=0, v2=50Hz, and v1=3Hz. Under this low speed condition, each exhaust fan does not rotate freely with the disturbing airflow, which can avoid the start-up failure when each exhaust fan is officially started.

[0078] At this point, when the exhaust fans in the outlet duct manifold coupling are divided into two groups, the first group consists of three exhaust fans. After the outlet ducts of the three exhaust fans are coupled together, steam is discharged through a manifold duct. The second group consists of one exhaust fan. The three exhaust fans in the first group are designated as exhaust fans 11, 12, and 13, respectively, and the exhaust fan in the second group is designated as exhaust fan 21. The four fans in the system are started sequentially starting from subscript 11, as follows:

[0079] like Figure 4 As shown, the exhaust fan 11 is officially started according to method A, that is, it starts at the initial speed v0 at time t0, runs for t1 = 25s and reaches the target speed v2, and then runs at speed v2 for t2 = 5s. The start-up cycle of the exhaust fan 11 is completed, and then it runs at speed v2.

[0080] Simultaneously with the start of exhaust fan 11, exhaust fans 12 and 13 are both micro-started according to method B, that is, they start synchronously at an initial speed v0, and maintain a micro speed v1 after reaching it. When the start-up cycle of exhaust fan 11 is completed, that is, after the system has run for t1+t2=30s, exhaust fan 12 is started according to method C. That is, exhaust fan 12 runs at a micro speed v1 as the starting speed for t1=25s to reach the target speed v2, and then runs normally at speed v2 for t2=5s, thus completing the start-up cycle of exhaust fan 12. After that, it maintains the speed v2.

[0081] When the start-up cycle of exhaust fan 12 is completed, that is, after the system runs for 2t1+2t2=60s, exhaust fan 13 is started according to method C. That is, exhaust fan 13 runs at a low speed v1 for t1=25s to reach the target speed v2, and then runs normally at speed v2 for t2=5s. The start-up cycle of exhaust fan 13 is completed, and the first coupled combustor exhaust fan group is started.

[0082] Then, exhaust fan 21 is officially started according to method A, that is, after the system runs for 3t1+3t2=90s, exhaust fan 21 starts at the initial speed v0, runs for t1=25s to reach the target speed v2, and then runs at speed v2 for t2=5s, completing the start-up cycle of exhaust fan 21. After that, it maintains speed v2. At this point, the start-up and operation of all exhaust fans in the system is completed.

[0083] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A start-up control method for exhaust fans coupled to outlet duct manifolds, characterized by: The exhaust fans are divided into N groups, where N is an integer greater than or equal to 1; The i-th group consists of M i It consists of several exhaust fans. The outlet ducts of each exhaust fan are coupled together and then discharge steam through a manifold duct. M i Let i be an integer greater than or equal to 1, where 1 ≤ i ≤ N; The j-th exhaust fan in the i-th group is denoted as exhaust fan ij, 1≤j≤M i ; The startup control method includes the following steps: (1) Let i = 1; (2) The starting methods for each exhaust fan in group i are as follows: The initial speed v of each exhaust fan in group i 初始ij same; Let j = 1; start the exhaust fan ij according to method A. At the same time, except for the j-th exhaust fan in the i-th group, the other exhaust fans are micro-started according to method B. (3) When the start-up cycle of the exhaust fan ij is completed, proceed to step (4); (4) Let j = j + 1, and start the exhaust fan ij according to method C; (5) Repeat step (4) until j = M i ; (6) Let i=i+1; (7) Repeat steps (2) to (6) until i = N; Method A is as follows: the initial rotational speed of the exhaust fan ij is v. 初始ij The exhaust fan ij officially starts, the speed of the exhaust fan ij increases, and the start-up and operation time of the exhaust fan ij is t. 微ij The speed then reaches a very low speed V. 微ij Startup target time t 目标ij After reaching the target speed v 目标ij , t 目标ij >t 微ij Then maintain the target speed v 目标ij Continue running t 间隔ij The start-up cycle of the exhaust fan ij is completed, and the target speed v is maintained thereafter. 目标ij run; Method B is as follows: the initial rotational speed of the exhaust fan ij is v. 初始ij The exhaust fan ij begins a micro-start, the speed of the exhaust fan ij increases, and the micro-starting time t... 微ij The speed then reaches a very low speed V. 微 ij, then maintain a low rotation speed V 微ij Running, waiting to enter the formal startup; Method C is as follows: the exhaust fan ij is officially started, and the speed of the exhaust fan ij starts from a low speed V. 微ij Start increasing, officially start running target time t 目标ij After reaching the target speed v 目标 ij, then maintain the target speed v 目标ij Continue running t 间隔ij The start-up cycle of the exhaust fan ij is completed, and the target speed v is maintained thereafter. 目标ij run.

2. The start-up control method as described in claim 1, characterized in that: In step (2), the initial rotational speed v of each exhaust fan in the i-th group is... 初始ij =0.

3. The start-up control method as described in claim 1, characterized in that: In method A, at least one of the following conditions (i) to (v) is satisfied: (i) The time t of each row of blowers ij in the i-th group 微ij same; (ii) The micro-speed V of each row of steam blowers ij in group i 微ij same; (III) The target time t for each row of steam blowers ij in the i-th group 目标ij same; (iv) The target rotational speed v of each steam blower ij in group i 目标ij same; (v) The interval t between each row of steam blowers ij in the i-th group 间隔ij same.

4. The start-up control method as described in claim 1, characterized in that: In method B, at least one of the following conditions (i) to (ii) is satisfied: (i) The time t of each row of blowers ij in the i-th group 微ij same; (ii) The micro-speed V of each row of steam blowers ij in group i 微ij same.

5. The start-up control method as described in claim 1, characterized in that: In method C, at least one of the following conditions (i) to (iv) is satisfied: (i) The micro-speed V of each row of steam blowers ij in group i 微ij same; (ii) The target time t for each row of steam blowers ij in the i-th group 目标ij same; (III) The target rotational speed v of each steam blower ij in group i 目标ij same; (iv) The interval t between each row of steam blowers ij in the i-th group 间隔ij same.

6. A continuous casting machine, characterized in that: The exhaust fan includes an outlet duct manifold coupling, and the exhaust fan adopts the start-up control method described in any one of claims 1 to 5.

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