JPS5831519B2 - Parallel operation method for multiple gas holders - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a gas distribution system in which a plurality of gas holders are connected to one or more gas generating sources and gas consuming machines, respectively, and a parallel operation method of the plurality of gas holders at the same level. Regarding.

Originally, a gas holder was designed to provide safety protection equivalent to the time needed to switch fuels at each factory (gas consumption machine) in the event of a sudden accident (for example, a sudden wind shutdown in a blast furnace) of a gas generation source connected to the gas distribution system to which the gas holder belongs. The purpose of the gas holder is to secure the amount of gas, absorb fluctuations in supply and demand between the gas generation source and the gas consumption side, and ensure efficient gas use and smooth supply. to have.

■ Easy to operate and monitor.

■ Install the holder in a position that absorbs fluctuations in gas generation and consumption and allows for full use of the holder.

■ Install in a location that can save on overall operating costs, including piping.

■ There must be open space.

It is required to satisfy the following conditions.

In particular, from the viewpoint of ease of operation and safety, it is common to install one holder for gas types.

However, in steel factories, for example, when the capacity of existing holders becomes insufficient due to an increase in production scale and it is necessary to install additional gas holders, the following methods are usually forced to be selected.

In other words, ■ Reusing the existing holder and installing a new holder with the full capacity, or ■ In the case where it is unavoidable to add a holder with only the insufficient capacity, and it is installed adjacent to the existing holder. The same method is basically used for single-unit operation, in which one holder is held at a security level and the other is used for fluctuation adjustment.

Either.

In the case of item (■) above, the construction cost is extremely high, and the holder construction site requires the largest area compared to item (2) or the method of the present invention. When performing this, operation without a holder is forced, and on the other hand, even in the case of item
Furthermore, since one of the holders is maintained at a safety level, there is a drawback that smooth operation of the holder cannot be confirmed at all times when the holder is raised and lowered.

The present invention has been made to solve the above-mentioned drawbacks, and is characterized by a gas distribution system in which a plurality of gas holders are interconnected with one or more gas generation sources and gas consumption machines. In the step, the level signal value of the specific holder (any one holder among the plurality of holders) is input and set to the level controller, and in the level controller, the level signal value of the setting device and each other holder except the specific holder is input and set. A continuous comparison operation is performed with a level signal value, and the opening degree of the gas distribution system flow control valve is adjusted based on the output signal value, and multiple holders are held at the same holder level. The purpose is to provide a parallel operation method.

The same holder level as used in the present invention means, for example, A(100000771") B(
150,000 m') This means that the capacity ratios of the two gas holders, that is, the ratio of the current storage capacity to the total capacity of the holders, are the same, and controlling in this way is called equal level control.

For example, if A holder is at 60% position, B holder is also at 60% position.
% position.

FIG. 2 is a plant system control diagram according to the present invention, showing a state in which a new gas distribution system (indicated by thick lines) is connected to an existing gas distribution system (indicated by thin lines).

1 is an existing gas holder (hereinafter referred to as holder 1), 2 and 3 are gas generation sources such as a blast furnace, and 4, 5 and 6 are
is a gas consumer such as a boiler, and the gas pipes 7, 8,
9 and 10, and constitute an existing gas distribution system.

Reference numeral 11 denotes a newly installed gas holder (hereinafter referred to as holder 2), which can be formed to have the same capacity as the Al holder or an appropriate capacity.

12 is a newly installed gas generation source, and 13 is a newly installed gas consumption machine.

Said 2 holder 11. The gas generation source 12 and the gas consumer 13 are mutually connected to the new gas piping 14 and constitute a new gas distribution system.

The new gas distribution system is connected to the existing gas distribution system via a flow control valve 15.

Reference numeral 16 denotes a drive system for the flow control valve 15, which is composed of, for example, an electro-hydraulic control machine.

1T is a level controller, 18 and 19 are AI and shoe 2 holders for the level controller, and level signal value input circuit 2.
0 is an output signal circuit from the level controller 17, which is electrically connected to the flow control valve drive system 16, for example.

Reference numeral 21 denotes a comparator which converts each holder to a reference level when a plurality of holders with different capacities are operated in parallel.

First, prior to the completion of the present invention, the inventors studied the actual conditions such as gas pressure fluctuations or gas flows in the existing gas distribution system, and found that the pressure balance of the existing gas distribution system was determined by the Al holder (existing holder). It was found that the gas pressure at a specific point in the gas distribution system was determined by the pressure drop due to the flow rate toward the boiler 1 holder.

In other words, pressure fluctuations occur following fluctuations in the flow rate toward the holder 1, and if a pressure loss source such as an orifice plate is inserted into this gas distribution system, naturally the resistance will be large. In addition, rapid fluctuations in flow rate due to gas generation sources such as simultaneous replacement of hot stoves, blast furnace slip, etc. will also cause rapid increases in the gas pressure at specific points in the gas distribution system. I found out that.

Furthermore, since the surplus gas generated in the new gas distribution system has a unidirectional gas flow, it is necessary to keep the gas pressure at the connection point to the existing gas distribution system as low as possible, and
It is a process that avoids any impact on the existing gas distribution system during operation, that is, ■ it does not require an increase in personnel to implement the present invention, and ■ it has low equipment costs and is a simple system. ■It is possible to connect with existing equipment in a short period of time, and the modification of existing equipment can be kept to a small scale.■It is possible to prevent abnormal situations with multiple holders, and to prevent sudden changes in gas generation and gas consumption. Various studies were conducted to satisfy the following conditions: (1) gas holders must be operated in parallel with the existing gas distribution system from the start of operation of the new gas distribution system;

In view of the above-mentioned series of conditions, the inventors used an analog computer, incorporated into the computer a control system that could take into account the above-mentioned conditions, and combined the new gas distribution system with the existing gas distribution system. A simulation was attempted by inputting the unbalanced gas balance conditions for the case.

As a result, it was found that parallel operation is possible by using the level of each holder as a process feedback input and controlling the communication flow rate between each holder to the same level as a control method.

Furthermore, as a result of repeated consideration of the setting position of the connecting flow rate control valve (hereinafter simply referred to as flow rate control valve), no particular difference was found whether it was installed at any point in the existing or newly installed gas distribution system. For example, as shown in FIG. 2, the gas distribution system is installed near the connection point between the new gas distribution system and the existing gas distribution system.

A case will be described in which two gas holders are operated in parallel based on the plant system control diagram shown in FIG.

In this case, in the sense that the entire gas distribution system is unidirectional,
The pressure of the second holder 11 is set higher than that of the &1 holder 1 by a certain amount.

This constant pressure is determined by the pressure drop of the flow control valve 15 and the installation system, and it was found using an analog computer that there is a limit range that is most suitable for control and that reduces the cost increase of the gas holder.

In the above case, the set pressure of &2 holder 11 can be set lower than A,1 holder 1 by a certain pressure.

For example, a float type level meter (not shown) is attached to the A1 holder 1 and the shoe 2 holder, and the level signal value of each holder is constantly sent to the level controller 1 through circuits 18 and 19.
7 is entered.

In this case, the level signal value of the specific holder, that is, &2 holder 110, is set as the setting value of the level controller 17, while the level signal value of the other holder, that is, the shoe 1 holder, excluding the specific holder, is input as the control signal value, and the level signal value of the level controller At 17, a proportional operation is performed between the set value and the control signal value, and the difference signal is inputted as an output signal value to the drive system (electro-hydraulic control device in FIG. 2) 16 of the flow rate control valve 15.

The drive system controls the flow rate of both gas distribution systems by adjusting the opening degree of the flow rate control valve 15 according to the magnitude of the input signal value from the level controller 17, and keeps both gas holders at the same level (strictly). Adjust so that the level is within a range that can be seen to be approximately the same.

Using an analog computer, we found that the control system's gain (GAIN), responsiveness, and operating speed of the flow control valve may have optimal values in order to reduce hunting or control delay.

Also, ■ (integral) and D (differential) operations are unnecessary for the level controller; P (proportional) operation is sufficient, and a special feed
We discovered that control can be achieved by obtaining the optimal gain using a simple method without the need to construct an expensive and complicated control system such as a forward sampling control system.

The above-described operation is constantly repeated to operate a plurality of gas holders in parallel.

FIG. 3 shows two gas holders (both holders have the same capacity of 100,000 m') in which the method of the present invention was used.

) shows an example of the control results (chart).

As seen in the chart, there is almost no difference in the holder level between the shoe 1 holder and the &2 holder, and very good control results are obtained.

In other words, the level difference between &1 holder 1 and A2 holder 11 is less than 1/100 of the total stroke of the holder, and g
It is within the range that can be said to be at the same level.

That is, since the level controller 17 does not perform an integral operation, a deviation remains, but stable control is achieved.

Since the levels of both holders are equal to g, the holder operation becomes a holder operation whose capacity is the sum of the capacities of both holders, and the speed of rising or falling is halved compared to the case of 1 group, increasing the safety level. At the same time, both holders themselves can be used effectively over the entire stroke.

Although the present invention has been described using an example in which two gas holders are provided, the present invention is not limited to this, and parallel operation is possible in all cases where two or more gas holders are provided.

That is, by controlling the specific holder and each holder other than the specific holder at the same level, it is possible to maintain favorable operating conditions such as the pressure balance of the entire gas distribution system and the unidirectionality of the gas flow.

By configuring and using the present invention as described above, the following effects can be obtained.

■ It is possible to significantly reduce construction costs compared to conventional construction methods.

■ The capacity of the new holder can be set to the minimum capacity compared to the conventional method, and therefore the site area is also reduced.

■ In the present invention, there is no need to provide an existing holder and a new holder adjacent to each other, and the layout can be freely designed.

(2) In the present invention, a plurality of holders are raised and lowered at the same time at the same level, so that the holders can be operated smoothly at all times and safety can be ensured.

In addition, the present invention provides parallel operation of a plurality of holders or tanks,
It can be applied to equipment systems for the purpose of storage or adjustment in which levels are controlled to change in conjunction with each other, and can be used, for example, in gas holders, oil tanks, powder hoppers, etc.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the same holder level control of the present invention. FIG. 2 is an apparatus and control system diagram provided for the present invention. FIG. 3 is a chart showing one embodiment of the present invention. 1: Existing gas holder (1 holder), 2: Gas source,
4, 5, 6 gas consumption machine, 7-10: gas piping, 11:
Newly installed gas holder (A2 holder), 12: Newly installed gas generation source, 14: Newly installed gas piping, 15: Flow rate control valve, 16: Drive system of flow rate control valve 15, 17: Level controller, 18, 19
Input circuit for A1 and A2 holder level signal values to the Nirepel controller, and output signal circuit from the Nirepel controller 17.

Claims (1)

[Claims] 1. In a gas distribution system in which a plurality of gas holders are interconnected with one or more gas generation sources and gas consumption machines, the level signal value of a specific holder is input and set to an L novel controller. In addition, in the level controller, the set value and
Continuously compare the level signal values of each holder other than the specific holder, and use this output signal value to adjust the opening of the gas distribution system flow control valve to maintain the holder level at the same level. A parallel operation method for multiple gas holders.