KR100460659B1 - a control system for furge and re-injection process on transport pipe of pulverized coal injection equipment malfuctioning - Google Patents

Abstract

The present invention provides a pulverized coal injection facility control system capable of performing a purge process and a re-injection process by automatically operating a three-way valve without operating a blow lance valve while maintaining the distributor pressure and the furnace pressure stable. The present invention is provided with a pressure bath insulated acid for adjusting the distributor pressure to maintain the difference between the distributor pressure and the furnace pressure in a predetermined range, the switching operation of the three-way valve required for the purge process and the re-blowing process is the difference in the pressure Is performed in a predetermined range, and when the distributor pressure is higher than that, the three-way valve can be returned to its original state to lower the distributor pressure to prevent an accident such as damage to the pipe protection disk and the blown lance.

Description

Control system for purge and re-injection process on transport pipe of pulverized coal injection equipment malfuctioning

The present invention relates to a control system for protecting the blow lance and the like in the event of an abnormality in the transfer main of the pulverized coal injection facility, in particular, in the case of performing a purge and re-injection process to repair the failure occurred in the transfer main main and It relates to a control system that allows the pressure difference in furnace pressure to automatically maintain a set range.

Referring to Fig. 1, the operation of the pulverized coal injection facility will be described. In the feeder 20, the pulverized coal is transferred to the pick-up machine 40 using nitrogen pressure, and the air pressure is applied from the air compressor 30 to the pick-up machine. The pulverized coal in 40 is transferred to the distributor 50, and then the pulverized coal in the distributor 50 is transferred to the blast furnace body 70 through a plurality (n) three-way valves 52. A plurality of tuyere 60 is formed on the side of the blast furnace body 70, and the tuyere 60 is provided with a blow lance 66 for blowing pulverized coal, the blow lance through the three-way valve 52 It is configured to be able to be transferred to the blast furnace body 70 along the intake pipe 54 connected to the 66 respectively. In addition, the operation unit 120 and the flow tank insulated acid unit 130 which input the blowing amount into the blow setter 90 at the cab and receive the value measured by the furnace pressure gauge 65 together with the input blow amount are carried out as necessary. The air flow rate can be calculated and the set blow-off amount can be automatically maintained by adjusting the return air flow opening / closing valve 32 according to the calculated flow rate. Herein, suitable proportioners (not shown) may be used to convert the set blowing amount and the furnace pressure into a return air flow rate.

In such a pulverized coal injection facility, the pick-up machine 40 is blocked by pulverized coal during pulverized coal injection, pulverized coal leakage occurs due to blockage or abrasion of a part of the transfer main pipe 44 or a failure occurs in the distributor 50. Can be. In the event of such a problem, repair of the installation or replacement of some equipment is required.

In this way, in order to perform repair and replacement work in the pulverized coal injection facility, firstly, the first and second blow valves 22 and 24 are interrupted to stop the injection of pulverized coal and return air supplied from the air compressor 30. Pulverized coal in pipes and the respective equipment parts of the transfer main pipe 44, etc. should be removed by passing through. This is called a purge process.

After the purge process, the first valve 62 in the blow lance 66 is operated to block the return air from the air compressor 30, and the second valve 64 is opened to blow the cooling air from the separate blower. It is introduced into (66) to cool it. In the process of blocking the return air by operating the first valve 62 of the blow lance, the distributor pressure increases according to the number of the first valve 62 of the blow lance being blocked. It should be kept large enough. Otherwise, if the furnace pressure becomes larger than the distributor pressure, damage to the equipment such as blown lance 60 due to hot air in the blast furnace body 70 is caused. On the contrary, if the distributor pressure is greater than the predetermined pressure than the furnace pressure, the distributor 50 may cause a problem that the pipe protection disk 47 at the bottom may be broken.

Looking at the conventional conveying air blocking and purging process to solve this problem, the first operator is disposed at the position of the blow lance to block the first valve 62 of the blow lance by the manual operation and to close the second valve (64). The conveying air is shut off in an open manner, and in this manner, the valves from the first blow lance to the nth blow lance are sequentially operated. On the other hand, while the second operator in the cab that can communicate with the first operator visually observes the distributor pressure indicator, the second operator increases in proportion to the number of the blow lances 66 in which the first valve 62 is blocked. When the dispenser pressure approaches a certain value or more, the first worker has been notified and the operation of the blow lance 66 has been stopped.

As described above, the manually operated conveying air shutoff operation makes it difficult to maintain the pressure difference (distributor pressure-furnace internal pressure = P) between the distributor pressure and the furnace pressure within a certain range, and the blow lance is operated by manual operation. Mistakes are likely to cause problems. Therefore, in the conventional pulverized coal injection facility, in the conveying air blocking and purging process, the internal pressure of the furnace becomes higher than the distributor pressure so that the hot air in the furnace flows into the distributor side, so that the blowing lance, the flexible hose, the blowing pipe, the first valve of the blowing lance and the second Large equipment accidents such as deformation and rupture of the valve occur, or on the other hand, the distributor pressure is increased by more than the predetermined amount, and the internal pressure of the transfer main pipe rapidly rises, so that the pipe protection disk disposed under the distributor There has been a problem that is broken.

As described above, in the case of repairing a problem in the case of a problem in the feed main of the pulverized coal injection facility, automated control that can carry out the blocking air and purge process while maintaining the predetermined pressure difference between the distributor pressure and the furnace pressure. System has been required.

In order to solve the above problems, an object of the present invention is to provide a pulverized coal that can perform the purge process and the re-blowing process by automatically operating the three-way valve without operating the suction lance valve while maintaining the distributor pressure and the internal pressure of the furnace Provide blowing facility control system.

1 is a schematic view showing a conventional pulverized coal injection facility.

Figure 2 is a schematic diagram showing the pulverized coal injection facility according to the present invention.

3 is a circuit diagram showing a control system of the pulverized coal injection facility according to the present invention.

4 is a circuit diagram showing a valve operation control unit of the pulverized coal injection facility according to the present invention.

5 is a control flowchart of the control system of the pulverized coal injection facility according to the present invention.

<Description of Signs of Major Parts of Drawings>

35: return air flow measurement unit 50: distributor

52: three-way valve 55: distributor pressure measuring unit

65: furnace pressure measuring unit 90: blowing amount setting unit

95: fuzzy control unit 100: pulverized coal blowing facility control system

120: calculator 130: flow tank insulation acid unit

150: pressure vessel insulation acid unit 170: valve operation control unit

175: subtractor

The present invention is provided in a pulverized coal injection facility including a flow opening / closing valve for adjusting a flow rate of conveying air provided from an air compressor, a furnace internal pressure measuring unit for measuring the pressure in the blast furnace, and a distributor pressure measuring unit for measuring the pressure in the distributor. A control system for maintaining a distributor pressure greater than the internal pressure and maintaining the difference in pressure within a predetermined range during purging and reblowing the pulverized coal injection facility, wherein the internal pressure measured by the furnace internal pressure measuring unit and the distributor pressure measuring unit A pressure tank insulated acid unit for calculating a return air flow rate necessary to maintain the set range when the difference in the distributor pressure measured in S is smaller than a set range, and controlling the flow open / close valve to supply the calculated return air flow rate; When the difference between the furnace pressure and the distributor pressure is within the setting range, the plurality of three-way valves are sequentially arranged with the distributor side. If the pressure difference is greater than the set range, the valve is controlled to open to the distributor side in reverse order from the three-way valve cut off at that time, thereby lowering the dispenser pressure to maintain the difference in the pressure in the set range. It provides a control system including an operation control unit.

In addition, the present invention further comprises a purge pipe connected to the lower end of the three-way valve, and a cooling blower connected to the other end of the purge pipe tube to introduce a cooling blower through the three-way valve into the intake pipe, the valve operation control unit When the pressure difference between the distributor pressure and the furnace pressure is in the setting range, the plurality of three-way valve can be made to open to the purge pipe side while sequentially blocking the plurality of three-way valve.

In addition, the present invention is to switch to selectively connect the flow opening and closing valve to the flow tank insulated acid unit for controlling the flow opening and closing valve and the flow tank insulated acid and the pressure tank insulated acid unit to convey the pulverized coal in accordance with the setting of the blowing amount It may further include a selection switch.

Although the first valve and the second valve of the blown lance have been adjusted by manual operation in the conventional conveying air blocking and purge process, the present invention does not adjust the valve of the blown lance by an automated system, but is conveyed by the pressure bath insulated acid unit. By adjusting the air flow rate to the appropriate distributor pressure, the operation of the three-way valve can be automatically controlled while maintaining the furnace pressure and the difference within the set range. Therefore, the present invention can perform a safe conveying air blocking and purging process, unlike the conventional method.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail with reference to drawings.

2 is a schematic diagram of a pulverized coal injection facility according to an embodiment of the present invention. The pulverized coal injection facility selectively opens and closes the pressure tank insulated acid unit 150, the valve operation control unit 170, the flow tank insulated acid unit 150, and the pressure tank insulated acid unit 150 in addition to the conventional pulverized coal intake facility shown in FIG. 1. It consists of the selection switch part 105 connected to the valve 35. As shown in FIG. In addition, a purge pipe (84) connected to the lower end of the three-way valve, and a cooling blower (80) connected to the end of the purge pipe (84) is further provided.

Hereinafter, the operation of the pulverized coal injection facility according to the present embodiment will be described generally.

In the normal pulverized coal injection process of this embodiment, the flow rate tank insulated acid supply unit 130 is connected to the return air flow opening / closing valve 32 using the selection switch unit 105, and the pulverized coal injection amount is blown by the blow amount setter 90. Set. Subsequently, the calculator 120 calculates a flow rate of the return air for transporting the pulverized coal set in relation to the furnace pressure. That is, the conversion value of the return air is calculated according to the pressure of the blowing air measured by the furnace internal pressure measuring unit 65, and the return air conversion value required according to the set blowing amount is calculated by the pressure of the blowing air. The actual required return air flow rate is calculated by subtracting the return air conversion value. Here, the pressures of the blowing amount setting unit 90 and the furnace internal pressure measuring unit 65 are converted into the return air values by the first proportioner and the second proportioner (not shown), respectively, and are input to the calculation unit 120. .

In this case, when an abnormality occurs in the transfer main pipe 44 during the normal blowing process, the blowing process must be stopped, the return air is blocked, and the purge process is executed to repair the same. In order to perform such a return air purge and purge process, the selection switch 105 is switched to a pressure control mode to connect the pressure bath insulated acid supply unit 150 to the return air flow valve 32. On the other hand, the distributor pressure measured from the distributor pressure measuring unit 55 disposed in the distributor 50 is provided to the pressure bath insulated acid unit 150, and the pressure bath insulated acid unit 150 from the distributor pressure measurer 55 The flow rate control valve 32 calculates a difference between the provided distributor pressure and the pressure measured by the furnace internal pressure measuring unit 65, and the difference P between the distributor pressure and the furnace pressure is in a predetermined range. Adjust the return air flow by controlling the opening and closing of the. Here, the predetermined range varies depending on the physical conditions of the equipment, but in general, when the internal pressure of the furnace is constant, it is larger than the distributor pressure which keeps stable so as not to be introduced into the distributor side from the hot air of the blast furnace, It is determined in a range smaller than the distributor pressure such that breakage or the like occurs. In the present embodiment, the upper and lower limits of the pressure difference are set to 0.4 kg / cm 2 &lt; P <4.0 kg / cm 2, whereby the calculation formula of the pressure bath insulation acid part is set to configure the valve operation control part.

3 shows in detail a control system 100 characterizing the present embodiment.

Referring to Fig. 3, in addition to the conventional configuration for controlling the return air flow rate according to the pulverized coal injection amount setting, the pressure bath insulation acid unit 150, the selector switch 105 and the third proportioner 126 according to the present invention are provided. Is shown.

In the operation for normal operation, as described above, the selector switch 105 is set to the flow rate control mode, and the conventional flow chamber insulated acid unit 120 and the return air flow opening / closing valve 130 are connected to each other, and the blow amount setting unit ( If the blowing amount is set in (90), it is converted into the return air flow amount according to the blowing amount by the first proportioner 102, and converted into the additionally required return air flow amount according to the furnace pressure by the second proportioner 104. do. The converted flow amount is input to the calculation unit 120 and summed up, where the summed flow amount is subtracted from the current flow of return air flow measured by the flowmeter 35 so that the flow rate tank insulated part 130 is currently additionally required to be returned. Calculate the air flow rate. According to the calculated return air flow rate, the flow rate tank insulated acid unit 130 is configured to control the return air flow opening / closing valve 32.

When such an abnormality occurs during the normal operation such as the transfer of the pulverized coal stop, and the selection switch 105 to switch the pressure control mode to connect the flow opening and closing valve 130 to be controlled by the pressure vessel insulated acid unit 150 , By adjusting the furnace pressure measured by the furnace internal pressure measuring unit 65 appropriately using the third proportioner 126 to obtain a difference P from the distributor pressure measured by the distributor pressure measuring unit 55 and adjusting the pressure. Input to the calculator 150. The pressure bath insulation acid unit 150 adjusts the return air flow opening / closing valve 32 so that the pressure difference of the distributor increases and decreases in a predetermined range.

In addition, although the control system 100 which concerns on this embodiment was abbreviate | omitted in FIG. 3, it includes the valve operation control part shown in detail in FIG. The valve control operation unit controls the operation of the three-way valve according to the difference between the distributor pressure and the furnace internal pressure that are varied in real time.

Referring to Figure 4, the valve operation control unit 170 will be described in detail. The valve operation control unit is connected to the purge operation unit 95 consisting of a branch pipe purge start switch, a main pipe purge start switch, and a branch pipe purge end switch to receive a signal for controlling the valve operation, and at the parts ⓐ and ⓑ of FIG. Each of the three-way valve 52, the blower air shutoff valve 82, and the lance purge shutoff valve 86 are automatically controlled according to the difference P between the distributor pressure and the furnace internal pressure, including a grounded subtractor.

5 shows a control flowchart by the control system 100 according to the present invention.

4 and 5, the operation of the control system 100 according to the present embodiment will be described in detail. In the case of starting the pulverized coal injection (step 200), when the transfer main body 44 or the pick-up machine 40 is blocked or requires repair, or when an abnormality occurs in the dispenser 50, the driver operates the purge control unit 95. The main purge start switch 97 of the main tube purge is turned on (step 202), and the first and second intake valves 22 and 24 are blocked to stop the injection of pulverized coal (step 204). In this way, only the return air is introduced for a predetermined time to purge the piping and each device. Subsequently, when the branch pipe purge start switch 96 is operated in the on state (step 206) to execute the branch pipe purge process according to the present embodiment, the contact point R1 is turned on, and the blower air shutoff valve 82 Open and the lance purge cutoff valve 86 is closed (step 208). If the output value C obtained by the subtractor 80 is greater than a (where a is the subtractor output value corresponding to the difference P between the distributor pressure and the furnace internal pressure 0.4 kg / cm 2), selection By selecting the switch 105 in the pressure regulation mode, the dispenser pressure is automatically controlled. This automatic adjustment of the distributor pressure is as described in the pressure vessel insulated acid unit 150.

On the other hand, the relay R4 is driven, the contact R4 is turned on, the relay R6 is driven and the first three-way valve is switched to the branch pipe purge tube 84 side to blow the suction pipe 54 into the branch pipe purge pipe. Connected to 84, the air is introduced into the cooling blower 80 (step 212). After a certain delay time ends (step 214), it is then determined whether or not the output value C of the subtractor 175 indicating the difference between the distributor pressure and the furnace pressure is greater than a (step 216), which is greater than a and the output value ( If C) is greater than h (P = 4.0 kg / cm 2) (step 218), if it is smaller than h, the contact T1 is connected after the predetermined delay time by the timer T1 to purge the second three-way valve. It is switched to the branch pipe 84 side (step 220). As such, when the three-way valve previously switched to the purge branch 84 is maintained at a suitable pressure difference for a predetermined time, the three-way valve in the next order is operated to operate the n three-way valves sequentially (step 222). To this end, the circuit configuration as shown in FIG. 3 can be used to enable sequential operation, but this is only an example, and the sequential operation can be performed only when a constant pressure difference is established on the premise of securing a delay time and operating the preceding valve. Various circuits capable of in-valve operation can be configured, and other such embodiments also belong to the present invention. Here, when the output of the subtractor 175 is not greater than a, the end of the predetermined delay time is a necessary time for properly raising and stabilizing the distributor pressure in the pressure bath insulation acid unit 150.

In addition, it is determined whether the output value C of the subtractor 175 is larger than h (P = 4.0 kg / cm 2) (step 218), and when the output value C is larger than that, the contact point R5 is turned off, and the purge pipe 84 of the subsequent three-way valve is turned off. The operation switched to the side is stopped, and since the contact T103 is in the off state, the first three-way valve is returned to the blown state and the dispenser pressure is lowered (step 230). In this way, if C> h during the purge switching operation of any of the three-way valves, the three-way valve switched to the purge branch pipe 84 side is switched to the blown state from that point, and if C> h, the contact R5 is still off. Since the three-way valve is switched to the blown-up state in the reverse order to the switching order on the purge branch pipe 54 side, the switching operation of the blown-up state is stopped when the dispenser pressure is within the range (a <C <h). Subsequently, if it is in the above range, the operation of sequentially switching the three-way valve back to the purge branch pipe 84 side proceeds sequentially.

As a result, in the present embodiment, the valve P in the blow lance 66 as in the prior art is not operated manually, and the difference P between the distributor pressure and the furnace internal pressure is 0.4 kg / cm 2 &lt; P <4.0 kg / cm 2 (a < It can be performed stably and quickly by automating the switching operation of the three-way valve for the branch pipe purging process while maintaining the condition in the range of C <h). In this way, when the switching operation of the three-way valve is completed (step 222), the driver notifies the end of the main purge (step 224) and closes the return air shutoff valve 34 (step 226) to transfer the main pipe 44 or the like. The possibility of repairs will be established.

In the case of starting the re-injection of pulverized coal after the completion of the repair and replacement work, the driver executes main pipe purge and opens the return air valve 34. In addition, the selection switch 105 is operated to connect the flow tank insulated acid unit 130 to the flow opening / closing valve 32. In this case, since the branch pipe purge state continues, the blower air shutoff valve 82 is opened, and the lance purge shutoff valve 86 is kept in a blocked state. In such a condition, the return air is introduced, and the valve operation control unit 170 operates the three-way valve switched to the purge state according to the difference between the distributor pressure and the furnace internal pressure output from the subtractor 175. That is, in the state where all three-way valve switching operations to the n-th three-way valve are completed, the branch purge end switch 98 is turned on to drive the relay R3, and the contact R1 is turned off through the relay R1. Let's do it. Subsequently, when the difference between the distributor pressure and the furnace pressure is maintained at P> 0.4 kg / cm 2, the switch is sequentially switched from the n-th three-way valve to the blown pipe 54 from the distributor 50. The switching operation of the three-way valve is continued to the switching operation of the next three-way valve under the condition of maintaining a stable pressure for a predetermined time. Here, using a timer (T101 to T (100 + n)) for a certain time delay, if the pressure difference during the time out of P> 0.4kg / ㎠ to switch back to the purge pipe 84 side. In this way, when the n three-way valves are operated in sequence and all three-way valves are switched to the blown state, the branch pipe purging process is completed.

As described above, according to the present embodiment, even in the process of operating the three-way valve for re-blowing, it is possible to perform the dispenser pressure and the furnace internal pressure stably at 0.4 kg / cm 2 <P <4.0 kg / cm 2 stably.

In addition, as shown in Fig. 2, a separate purge pipe 84 is connected to the three-way valve 52 side of the branch pipe 37 connected to the three-way valve 52 from the air compressor 30, and the purge pipe 84 The branch pipe purge is performed through the cooling blower 80 mounted at the other end thereof. However, it is preferable to omit the conventional branch pipe and connect the purge branch pipe 84 directly to the three-way valve 52. However, as shown in Figure 2 is only an example used to modify the conventional pulverized coal injection facility.

As described above, according to the present invention, in the case of a problem such as the transfer main of the pulverized coal injection facility occurs, in the case of performing the repair and replacement work, in order to shut off the return air and to carry out the purge process, and re-injected pulverized coal after the repair and replacement work In this regard, the dispenser pressure and the furnace pressure can be automatically compared and judged during the process to effectively prevent the dispenser pressure from being greatly raised or lowered and to achieve a rapid process. As a result, it is possible to minimize the occurrence of equipment accidents and safety accidents due to the difference between the distribution pressure and the internal pressure, and to minimize the reduction of the charter production, and contribute to the stabilization of the blast furnace operation.

The detailed description of the embodiments of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many improvements and modifications are possible in light of the above. It is intended that the scope of the invention be limited not by this detailed description, but rather by the claims. The above specification, embodiments are intended to provide a more complete description of the manufacture and use of the invention. There may be many embodiments without departing from the spirit and scope of the invention, which is defined by the appended claims.

Claims (3)

It is provided in the pulverized coal injection facility including a flow opening / closing valve which regulates the flow rate of conveying air provided from an air compressor, a furnace internal pressure measuring unit for measuring the pressure in the blast furnace, and a distributor pressure measuring unit for measuring the pressure in the distributor. In a control system for dispensing the pressure of the distributor greater than the internal pressure during purging and reblowing the equipment, and maintaining the difference of the pressure in the set range, The difference between the furnace pressure measured by the furnace internal pressure measuring unit and the distributor pressure measured by the distributor pressure measuring unit is calculated, and the return air flow rate required to maintain the set range when the difference in pressure is smaller than the set range is calculated. And a pressure bath insulated acid unit for controlling the flow opening / closing valve to supply the calculated return air flow rate; When the difference between the furnace pressure and the distributor pressure is within the set range, the plurality of three-way valves are controlled to be sequentially cut off from the distributor side. When the difference in pressure is greater than the set range, the three-way valve is reversed from the shut-off valve at that time. And a valve operation control unit which controls the opening to the distributor side in order to lower the distributor pressure so as to maintain the difference in pressure in a set range. The method of claim 1, A purge pipe connected to the bottom of the three-way valve, It is connected to the other end of the purge pipe further comprises a cooling blower for introducing a cooling blower through the three-way valve to the intake pipe, The valve operation control unit And when the pressure difference between the distributor pressure and the furnace internal pressure is within the set range, the plurality of three-way valves are opened to the purge pipe side while sequentially blocking the plurality of three-way valves from the distributor side. The method of claim 1, A flow tank insulated acid unit for controlling the flow opening / closing valve to convey the pulverized coal according to the setting of the blowing amount; And a selection switch for switching one of the flow tank insulated acid unit and the pressure bath insulated acid unit to be selectively connected to the flow shutoff valve.