JPS61200839A - Operation of gas separation cascade - Google Patents

Abstract

PURPOSE:To reduce the electric capacity of power source equipment for driving a cascade, by dividing the cascade into a plurality of re-start units and successively performing re-starting and speed re-raising at every re-start unit. CONSTITUTION:For example, a large number of separators constituting a cascade 10 are divided into first, second, ... i-th groups and the cascade 10 is divided into a first re-start unit, a second re-start unit 22, ... i-th re-start unit 23 and re-starting and speed re-raising are successively performed at every re-start unit. Therefore, electrical load at the time of re-starting can be dispersed and, as a result, the capacity of power source equipment for driving a plant can be reduced by 20-30%.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a method of operating a gas separation cascade, and more specifically, to a method for operating a gas separation cascade, and more specifically, a method for controlling power outage and recovery of a driving power supply that can reduce the electrical capacity of the cascade driving power supply equipment. This is related to the cascade restart method during power up.

<Prior art> Separation devices such as isotope separators are used to separate and collect specific component gases from mixed gas systems.
Since the separation effect and throughput of only one separator are small, a so-called cascade, in which a large number of separators are connected in series, is generally used.

When such a gas separation cascade is operated at full capacity, as shown in FIG. , the product in which the gas to be separated is concentrated flows from the top of the cascade to product stream 12.
As a result, waste products are taken out from the lowest stage of the cascade as a waste product stream 13.

Plan 1 - If the driving power supply is restored after a power outage during operation of the gas separation cascade, if the power outage is relatively short, it is recommended to supply gas inside the cascade to prevent a drop in the cascade operating rate. Conventionally, the method used was to maintain the circulating state and restart the cascade all at once when power is restored to increase the speed to the rated speed again.

<Problems to be Solved by the Invention> However, according to the above-described batch restart method, the number of restart units of the drive power source increases. Although such a batch restart takes an extremely short amount of time compared to other operating conditions, the capacity of the drive power supply equipment must be set sufficiently large in advance in preparation for the batch restart, so the power supply equipment is There is a tendency for plants to become larger and have larger capacities, which has been a factor in increasing plant construction costs.

Therefore, the present invention aims at plan 1 - miniaturization of drive power supply equipment,
The purpose of this invention is to provide a method for restarting a gas separation cascade upon power failure and power restoration of the driving power source, which enables the capacity to be reduced.

<Means for Solving the Problems> In other words, the present invention divides the cascade into a plurality of restart units when restarting and speeding up the cascade when the power supply for driving the gas separation cascade is restored after a power outage. This is a method of operating a gas separation cascade characterized by sequentially restarting each restart unit and increasing the speed again.

According to such a cascade restarting method, the electrical load at the time of restarting and speeding up again is distributed, and the electrical capacity of the drive power supply equipment can be reduced.

<Examples> The present invention will be briefly described below with reference to examples shown in the drawings. FIG. 1 shows a first cascade of separators according to the invention. Second, divided into i-th group,
First restart unit 21, second restart unit 22, respectively.
. . . shows a state divided into first restart units 23.

Fig. 2 shows the operating procedure according to the method of the present invention when the cascade is divided into two parts, a first restart unit and a second restart unit, for ease of explanation, and the vertical axis represents the configuration of the cascade. The rotational speed of the centrifugal separator is expressed as elapsed time on the horizontal axis. That is, a power outage (2) of the driving power supply occurs at the rated rotation (2) of the gas separation cascade, and the first restart unit is restarted (2) after the power is restored (2). As a result, only the first restart unit speeds up again as shown by the broken line (2) and reaches the rated rotation (3).

Then, by restarting the second restart unit (2) and raising the speed again, the entire cascade returns to the rated rotation (2).

Although the restart order of the restart units is arbitrary, it can be selected in consideration of the flow rate and pressure safety of the constituent separators from the cascade internal flow. For example, if the gas flow rate inside the cascade becomes unevenly distributed due to a power outage,
You can restart the restart unit where the flow rate is concentrated first, or
It is also possible to restart the restart unit that is a major cause of bias first.

FIG. 3 shows the cascade internal flow fluctuations represented by pressure or flow rate when the operating procedure is as shown in FIG. 2.

This graph shows that internal flow fluctuations are dispersed over time. For example, this means that by first restarting the restart unit where the flow rate was concentrated, the rotation speed is restored and the deviation in the internal flow rate is suppressed, and then the restart unit that was the cause of the deviation is restarted to bring the entire cascade to a steady state. means to recover.

By appropriately selecting the operating parameters, it is possible to make the cascade internal flow fluctuation width approximately equivalent to that in the case of conventional batch restart, and no safety issues arise.

Furthermore, when the cascade is divided into a plurality of restart units according to the present invention, it is preferable to make the number of divisions match the number of initial startup divisions of the cascade, since this will not result in the addition of δ1 installation equipment.

<Effects of the Invention> As explained above, according to the present invention, the cascade is divided into a plurality of restart units, and by sequentially restarting and re-boosting each restart unit, the electrical power at the time of restart is reduced. The load can be distributed, and as a result, the plant drive power supply equipment capacity can be reduced by 20 to 30%. Since this power supply equipment cost accounts for a small proportion of the plant construction cost, a significant reduction in plant construction costs can be expected.

In addition, by appropriately selecting a speed increase unit that corresponds to the flow rate and pressure horn condition inside the cascade, there is also the advantage that the safety of the separators that make up the cascade is improved and the operating rate of the cascade is also improved.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing the concept of dividing a large number of separators constituting a cascade into a plurality of restart units based on the present invention, and Fig. 2 shows the operating procedure according to the method of the present invention when the cascade is divided into two. Figure 3 is a graph showing changes over time in the internal flow fluctuations of the cascade when the operating procedure is as shown in Figure 2, and Figure 4 is an explanatory diagram showing a general gas separation cascade. . 10...Cascade, 21,22.23...Restart unit.

Claims (1)

[Claims] 1. When restarting and re-boosting the cascade when power is restored after a power outage for driving the gas separation cascade, divide the cascade into multiple restart units and restart and re-boost sequentially for each restart unit. A method of operating a gas separation cascade characterized by speed.