JPS6160116B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device (operator) for cyclic process control of a plurality of oil and gas generators that generate gas by catalytically cracking naphtha, etc., and in particular for operating a shift steam valve. Concerning improvements in circuits.

The well-known cyclic naphtha gas generator alternately repeats the heating period (blow period) and manufacturing period (make period).
The CO transformers are unit 10 and unit 2, which have the same configuration.
For two gas generators with Unit 20, one
They are installed to share a CO transformer. First, the case of standalone operation of unit 1 10 will be explained with reference to Figs. 1 and 2. The gas production process is divided into four processes: blow period, blow purge period, make period, and make purge period. starts from the blowing period, and the take-off valves 19a, 19
Close valve b, open stack valve 14, and open valve 1.
6 and 15 are opened to send heating oil (burner oil) and air (burner air) to heat the steam preheater 11 to store heat, and the heated exhaust gas is passed through the reactor 12 and waste heat boiler 13 to the stack valve 14. The blowing phase ends at about 50% of the total process. Then valve 14,1
5 and 16 and open valves 17 and 18 to send make oil and process steam into the steam preheater 11;
Catalytic cracking of naphtha is performed using the stored heat and the action of a catalyst, generating gas. The generated gas is guided into the transformer 30 by the suction pressure generated by opening the take-off valves 19a, 19b and the transform steam valve 31 to blow out the transform steam, and is guided into the transformer 30 by the subsequent relief holder (not shown). 40% of the makeup stage process has been completed. During this period, purge (blow purge and make purge) with steam (valve 17 open) at the end of the blow period and make period.
are set at a few percent each, and these processes are taken as 100% and one cycle process (160 seconds ~
220 seconds), and gas is produced by repeating this cycle.

Next, when operating two gas generators (No. 1 unit 10 and No. 2 unit 20) as a pair, first
0 starts from the blow period, then the second machine 20 starts when the first machine 10 enters the make period, i.e. 50
The blow period starts with a % delay. Each of the machines 10 and 20 produces gas in the same process as in the above-described individual operation with a 50% difference. That is,
When the first machine 10 is in the make period (or blow period), the second machine 20 is the blow machine (or in the make period)
They are operated in pairs. In this way, the make periods of each machine 10, 20 are performed alternately and do not overlap, so that each machine 10, 20 has a transformer 30.
and can be used interchangeably in common and subsequent lines.
Further, there is an advantage that fluctuations in the amount of gas produced and the amounts of raw material oil (make oil or naphtha), heating oil (burner oil or naphtha), secondary air, and steam used are reduced and averaged out.

The above steps are carried out using the power operated valves 14 to 18, 19 provided in each line of the plant shown in the first diagram.
a, 19b; 24-28, 29a, 29b are cyclically opened and closed in relation to each other according to predetermined timing and order. Valve operation control devices, that is, operators 40 and 50 are provided to control the opening and closing of each of these valves and to manage the operation of the gas production process.

Regarding the operator 40 for Unit 1 10,
The configuration functions will be explained with reference to the block diagram in FIG. In addition to preventing malfunctions and erroneous operations by the operator 40, the combination of opening and closing positions of each valve (process status), operating status (operation congestion), and process status (air pressure, naphtha pressure, operating hydraulic pressure) are checked, and if any abnormality is detected, the plant is inspected. A circuit is provided to shut down the device to a safe state. Each solenoid valve 14-1
8, 19a, 19b, and 31 are opened and closed by a valve opening/closing command signal issued from the control circuit 140 of the operator 40. Each valve 14-18, 19a, 1
The opening/closing results of valves 9b and 31 are detected by an opening/closing detector (proximity switch), for example, switches SW3 and SW4 of the transformation steam valve 31, which are electromagnetic valves, and are fed back to the operator 40 to check whether each valve has been opened and closed as instructed. Checks are made to see if the process has been completed completely (valve operation congestion check), the relationship with other valves, and the opening/closing position (process status check). Operator 4 for the above-mentioned machine No. 1 10
An operator 50 for the second unit 20, which has the same configuration and functions as the second unit 20, is also installed, and one set of operators 40, 50 can operate one gas generator 10,
20 respectively.

The relationship between the signals between the operators 40 and 50 and each valve is as described above.
Since there is only one unit for the two gas generators 10 and 20 (therefore, the two operators 40 and 50), there will be problems when the two gas generators 10 and 20 are operated as a pair. Opening/closing command signals issued from the operators 40 and 50 to the shift steam valve 31 and the shift steam valve 31 are shared so that the shift steam valve 31
The opening/closing detection signal fed back to the operators 40 and 50 is as follows.

First, the opening/closing command signal to the shift steam valve 31 will be explained. Each operator 40, 50 of the first unit 10 and the second unit 20 is provided with a control circuit 140, 150 that issues an opening/closing command signal, and each operator 40, 50 opens/closes one shift steam valve 31. be able to. When opening the valve 31, the low temperature take-off valve 19b,
The condition that the opening occurs after the opening of the opening 29b is set in advance.

One shift steam valve 3 in pair operation with 50% shift
1 will be described below. Unit 1 1
When an open command signal B is issued from either the operator 40 or 50 of the No. 0 or the No. 2 reactor 20 (after detection of the valve 19b, 29b open detection signal A), the shift steam valve 31 is opened. Also, for example, Unit 1 10
by the opening command signal B from the operator 40 of
The output of AND gate 1 operates monostable 2, the output of bistable 3 drives relay 4, and switch SW
1 becomes conductive, the shift steam valve 31 opens,
Therefore, for example, the operator 50 of the No. 2 machine 20
Even if a close command signal is issued from the converter, the relay 4a is demagnetized, and the switch SW2 is shut off, the shift steam valve 31 does not close (However, in the event of an abnormality, the plant stop circuit 5 is activated and the control circuit 140 resets the bistable 3. Then the valve 31 will close). That is, the valve 31 is closed only when a close command signal for the valve 31 is issued by both operators 40,50. This is valve 31
Switches SW1 and SW2 for (valve 31 opens when these switches SW1 and SW2 are connected)
This is realized by providing the operators 40 and 50 of both machines 10 and 20, respectively, and making these switches SW1 and SW2 a parallel circuit. This circuit configuration is designed so that when the other machine, that is, the pair machine (for example, the first machine 10) is in the blowing period and the operator 40 is commanding the valve 31 to close, the own machine (for example, the second machine 20) ), the operator 50 commands the valve 31 to open in order to make the process, and when such a pre-shield occurs, the valve 31 is opened. In this case, even if the valve 31 is actually opened despite the command to close the valve 31, the valve 19 is closed.
a, 19b are closed, and conditions are set in the control circuits 140, 150 of the operators 40, 50 so that the operation can be carried out without any trouble despite such a contradiction.

Next, the detection signal of the open/closed state of the valve 31 will be described. When the valve 31 is activated in response to an open or close command signal from the operators 40 and 50, it is detected whether the valve 31 is completely opened or closed by proximity switches SW4 and SW3, which are respectively provided at the open and close positions of the valve 31 body. , gives its detection signal to both operators 40,50. Since there are two operators 40 and 50 for one valve 31, the detected opening/closing detection signal is input to the operator 40 of the first unit 10, and is input to the operator 50 of the second unit 20.
An open/close detection signal is also sent to. The opening/closing detection signal of the valve 31 given to these two operators 40, 50 is sent to each machine 10, along with the opening/closing detection signal of other valves.
Used as a condition signal and confirmation signal for 20 plants.

The valve operation congestion circuit is provided for the purpose of monitoring whether the valve opening/closing operation is as instructed.
Even though an open or close command signal is issued from 0 or 50, if the valve does not open or close according to the command, or if the command signal stops midway and the command is not completely executed, the valve will open or close for a certain period of time. (Valve operating time)
Plan B will be shut down later. A switch SW3 provided on each valve, such as valve 31,
The actual open/close state signal detected by the open/close detection switch such as SW4 is checked.
In the case of two-machine pair operation, even though the own machine (for example, No. 1) is issuing a close command signal to the valve 31 during the blowing period, the other machine (for example, No. 2) is
When Unit No. 20) enters the make period, Unit No. 2 20)
The valve 3 is opened by an opening command signal from the operator 50.
1 is open.

The circuit for the shift steam valve 31 of the operators 40 and 50 of the prior art uses a simulated signal to set conditions and check for abnormalities in order to perform pair operation. A mixture of simulated signals creates a complex and difficult-to-understand circuit, and the simulated signals also differ from the actual open/close state. For example, when an open command signal is derived from one operator, the other operator assumes that the valve is open, even if it is not open due to a malfunction, and therefore outputs a close signal. , and performs logical processing. In this way, the open command signal from one operator is treated as a close signal by the other operator, called a simulated signal, without being based on actual detection. As a result, the occurrence rate of failures is high, and repairs are time-consuming, and operators and maintenance personnel are prone to misunderstandings when operating the plant or inspecting circuits. Furthermore, from a functional point of view, there is a lack of reliability in checking whether the valve 31 is open or closed.

The main purpose of the present invention is to simplify the circuit configuration and improve the reliability of the check function for the open/closed state of the shift steam valve 31, to eliminate the simulated signal of the shift steam valve 31 and to use only the true detection signal. In addition to modifying the original circuit, the aim is to enable safe pair operation using only real detection signals without using simulated signals.

In the present invention, each of the plurality of oil and gas generators is constructed by connecting a steam preheater 11, a reactor 12, and a waste heat boiler 13 in this order, and in the blowing period, the steam preheater 11 is a heating oil burner. The waste gas is discharged from the reactor 12 to the atmosphere via the waste heat boiler 13 and the stack valve 14,
During the make period, manufactured oil passing through the make oil valve and steam passing through the process steam valve 17 flow into the preheater 11.
The produced oil is introduced into the reactor 12 and preheated, and the produced oil is catalytically cracked by the action of a catalyst to produce gas, and then the produced oil is introduced into the reactor 12 or the waste heat boiler 1.
take-off valves 19a, 19b in connection with the outlets of 3;
is interposed, and each of the oil and gas generators has a single
The oil and gas production process consisting of the blow period and the make period is periodically repeated by sharing the CO transformer 30 at different times, and the gas is converted to the take-off valve 19a by steam passing through the conversion steam valve 31. ，
19b, the control device for the oil and gas generator sucked into the CO transformer 30 detects the open/closed state of the shift steam valve 31, and when the shift steam valve 31 is even slightly open, a closed state detection signal D is sent. means SW4, N1 for deriving the following; and a first means 14 for deriving the closing command signal E for closing the shift steam valve 31 of the certain oil and gas generator.
0, and a second means 15 for deriving a closing command signal for closing the transformation steam valve 31 of the other oil and gas generator.
0, the closed state detection signal D from the closed state detection signal deriving means SW4, N1, the close command signal E from the first means 140, and the close command signal from the second means 150 are generated simultaneously. 1 processing means 7, 8, 9, 10 for generating a stop signal; means SW3, N2 for deriving an open state detection signal when the shift steam valve 31 is even slightly closed; and means SW3, N2 for opening the shift steam valve 31. The open state detection signal from the open state detection signal deriving means SW3, N2 and the open command signal from the third means 140, 150 are generated simultaneously. when the second processing means 15 generates the second stop signal; the first processing means 7, 8, 9, 10; and at least the first and second stop signals from the second processing stage 15; a third processing means 11 that generates a stop signal when one of the signals is generated; a timer 12 that delays the signal from the third processing means 11 by a predetermined time period; An oil and gas generation device characterized in that it includes means 13, 5, and 140 for stopping the operation of the oil and gas generation device in a safe state and continuing the operation of the certain oil and gas generation device when there is no output from the timer 12. It is a control device for the device.

In one embodiment of the present invention, an AND gate 8 is used to combine a closed state detection signal D obtained by inverting the valve 31 closed detection signal C from the switch SW4 with an inverting circuit N1 and a high-level signal when the switch 7 is conductive.
Furthermore, in the blow purge period and the make purge period, the output of the inverting circuit N1 is used as is. The closed state detection signal D is at a high level if the valve 31 is even slightly open. Here, the switch 7 is controlled by the control circuit 150 of the operator 50 of the partner machine 20,
This is a switch that is turned on by a closing command signal of the shift steam valve 31. During the make purge period, the actual closing detection signal D is used to check the process status.
Therefore, according to the present invention, the check function can be further improved and the check effect can be increased.
The switches SW3 and SW4 are switches that are installed close to the main body of the shift steam valve 31 and detect whether the valve 31 is open or closed. One switch SW4 outputs a high-level output signal when the valve 31 is in the closed position (i.e., not closed), and when the valve 31 is out of the closed position and becomes even slightly open (i.e., not closed). ) does not output an electrical signal and becomes low level. The other switch SW3 is the valve 31
This is a switch that detects the open state of the switch, and its high-level output signal is conductive only when the switch is fully open. The signal from this switch SW3 is inverted by an inverting circuit N2. The output of the reversing circuit N2 is the output of the shift steam valve 3.
This is an open state detection signal that becomes high level when 1 is closed even slightly (that is, when it is not fully open), and is applied to the AND gate 15. Now, when the operator 40 issues a command signal to close the valve 31, the valve 31 starts its closing operation, and when the valve 31 is completely closed, a close output signal detected by the switch SW4 is derived, and the valve 31 is completely closed. If it is not fully closed or even slightly opened, the close output signal will not be output. The closed detection signal C is inverted by the NOT circuit N1 to become the closed detection signal D. These signals C and D can also be used in the process condition abnormality and valve operation congestion check circuit of the first machine 10.

The term "closed" here means not fully closed,
In other words, it means not only fully open but also slightly open. The switch SW4 derives a high level detection signal when the shift steam valve 31 is fully closed, and is low level when it is not fully closed, that is, when it is closed. Therefore, the fact that the closed state detection signal D representing the closed state is at a high level means that the output of the switch SW4 is at a low level, that is, it is not fully closed. This closed state detection signal D is derived from the inverting circuit N1.

Similarly, the term "open" refers to not being fully open; in other words, it refers not only to fully closed, but also to a state in which the degree of opening is slightly closed from the fully open state. The switch SW3 derives a high level detection signal when the metamorphic steam valve 31 is fully open, and is low level when it is not fully open, that is, when it is open. The open state detection signal indicating this open state is
This open state detection signal is obtained from an inverting circuit N2 that inverts the output of SW3, and is at a high level when it is in an open state.

To check the valve operation congestion, the actual signal, which is the closure detection signal D of the valve 31, is used as it is. According to the present invention, when the closing command signal E of the shift steam valve 31 is issued from the operator 40, the closing command signal E passes through the OR gate 9 and the AND gate 10.
is given to one input of As a response to this close command signal E, the valve 31 is not completely closed, that is, the close detection signal D is output from the inverting circuit N1, and the paired machine (No. 2 machine in this case) is not commanded to close, that is, the switch 7 is not closed. When the condition is that valve 3 is conducting due to the close command signal,
Valve 3 by 1 closed detection signal D and paired machine (unit 2)
At the time of closing command of 1, two signals called conductive signal F are
This is established at AND gate 8, and its output is given to the other input of AND gate 10. In this way, when the valve 31 closing detection signal D and the closing command signals E and F are generated from the operators 40 and 50 and the AND condition is met, the operation of Unit 1 is stopped in a safe state, and when the AND condition is not met, the operation of the No. 1 unit is stopped in a safe state. , Unit 1 will continue to operate. That is, in the AND gate 10, the output of the AND gate 8 is the first unit 10.
A high level output signal is sent from the AND gate 10 from the OR gate 11 to the timer 12, which indicates that the valve 31 is not closing as instructed.
After a certain period of time, the valve operation abnormality is stored in the bistable circuit 13, the control circuit 140 is operated by the plant stop circuit 5, and the No. 1 unit 10 is shut down to a safe state.

The predetermined period of time of the timer 12 is a predetermined time period that is longer than both the time it takes for the shift steam valve 31 to go from a fully closed state to a fully open state, and the time for it to go from a fully open state to a fully closed state. By setting in this way, malfunctions can be avoided.

However, during pair operation, if an open command signal is output from the pair machine (No. 2 unit 20) to the conversion steam valve 31, the pair unit (No. 2 unit 20) is in the make period, and the valve 31 is opened to start CO conversion. Since the gas generated in the vessel 30 must be passed through, the valve 31 must be kept open. Therefore, by eliminating the close command signal for closing the transformation steam valve 31 from the paired machine (No. 2 unit 20), the switch 7 is shut off and the AND gate 8 is prevented from outputting a high-level output signal. Avoid shutdown. When checking the make purge period to check the process status, the signal G is input to the OR gate 9, and the subsequent operations are the same as described above. The other operator 50 is similarly configured. The switch SW3 outputs a high level signal when the valve 31 is open, and the valve 31 open detection signal and the valve 31 open command signal B are input to the AND gate 15.
The output of AND gate 15 is given to OR gate 11.

The switch 7, AND gates 8, 10, and OR gate 9 constitute a first processing means, and this first processing means detects the open/closed state of the shift steam valve 31 and detects that it is open even slightly. A closed state detection signal generated by a shift steam valve 3 of a certain oil and gas generator
When a close command signal for closing the shift valve 1 and a close command signal for closing the shift steam valve 31 of the other oil and gas generator are generated simultaneously, a stop signal is generated.
The AND gate 15 constitutes a second processing means, and simultaneously generates a closed state detection signal derived when the shift steam valve 31 is closed even slightly and an open command signal for opening the shift steam valve 31. generates a stop signal when The third processing means is constituted by an OR gate 11, and AND gates 10 and 15.
generates a stop signal when at least one of the outputs from the

As described above, according to the present invention, since no conventional simulated signal is used for operation checking, there is no need for a simulated signal generation circuit, and the configuration is greatly simplified compared to the prior art. The circuit can be realized using only real signals that match the actual open/close states of the shift steam valve 31. As a result, maintenance can be easily performed, and it is also useful in preventing illusions during driving operations.

[Brief explanation of the drawing]

Fig. 1 is a system diagram of a naphtha gas generator that forms the basis of the present invention and is used to explain the prior art, and Fig. 2 shows the manufacturing of each power-operated valve installed in the line of the naphtha gas generator shown in Fig. 1. A diagram showing the opening/closing state for the process, Figure 3 shows operators 40, 50 installed for each naphtha gas generator.
1 is a block diagram of an embodiment of the present invention showing the configuration of the present invention. 10... Unit 1 naphtha gas generator, 20...
Unit 2 naphtha gas generator, 11, 21... Steam preheater, 12, 22... Reactor, 13, 23...
Waste heat boiler, 14, 24...Stack valve, 15,
25... Burner air valve, 16, 26... Burner oil valve, 17, 27... Process steam valve, 18, 28
...Make oil valve, 19,29...Takeoff valve,
30...CO transformer, 31...Transformation steam valve, 32
... Naphtha source, 33, 35 ... Steam source, 34...
...Blower, 40... Unit 1 operator, 50...
Unit 2 operator, SW3, SW4...switch.

Claims (1)

[Claims] 1. Each of the plurality of oil and gas generators includes a steam preheater 1
1, a reactor 12, and a waste heat boiler 13 are connected in this order, and in the blowing period, the steam preheater 1
1 stores heat by burning heated oil in a burner, and its waste gas is released into the atmosphere from the reactor 12 through a waste heat boiler 13 and a stack valve 14, and during the make period, it is mixed with manufactured oil and process oil through the make oil valve. Steam through the steam valve 17 is introduced into the preheater 11 and preheated, and the manufactured oil is catalytically cracked in the reactor 12 by the action of a catalyst to produce gas, which is then transferred to the reactor 12 or the waste heat. Take-off valves 19a and 19b are interposed in connection with the outlet of the boiler 13, and each of the oil and gas generators has a single CO
The oil and gas production process consisting of the blow period and the make period is periodically repeated by sharing the transformer 30 at different times, and the gas is converted into the take-off valves 19a, 19
In the control device for the oil and gas generator sucked into the CO transformer 30 via b, the open/close state of the shift steam valve 31 is detected, and when the shift steam valve 31 is even slightly open, a closed state detection signal D is sent. means SW4, N1 for deriving the following; and a first means 14 for deriving the closing command signal E for closing the shift steam valve 31 of the certain oil and gas generator.
0, and a second means 15 for deriving a closing command signal for closing the transformation steam valve 31 of the other oil and gas generator.
0, the closed state detection signal D from the closed state detection signal deriving means SW4, N1, the close command signal E from the first means 140, and the close command signal from the second means 150 are generated simultaneously. 1 processing means 7, 8, 9, 10 for generating a stop signal; means SW3, N2 for deriving an open state detection signal when the shift steam valve 31 is even slightly closed; and means SW3, N2 for opening the shift steam valve 31. The open state detection signal from the open state detection signal deriving means SW3, N2 and the open command signal from the third means 140, 150 are generated simultaneously. a second processing means 15 that generates a second stop signal; and at least one of the first and second stop signals from the first processing means 7, 8, 9, 10 and the second processing means 15. a third processing means 11 that generates a stop signal when a signal is generated; a timer 12 that delays the signal from the third processing means 11 by a predetermined time period; and a timer 12 that receives the delayed output from the timer 12 and An oil and gas generator characterized in that it includes means 13, 5, and 140 for stopping the operation of the gas generator in a safe state and continuing the operation of the certain oil and gas generator when there is no output from the timer 12. Control device for.