JPS6017996B2 - Control device for heat exchanger in concentrator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device for a heat exchanger in a concentrator that performs condensation processing using steam.

An example of such a concentration device is the radioactive waste treatment facility shown in FIG.

This concentrator includes a heat exchanger 2 disposed within a condenser 1, boils a treated liquid 3 in the concentrator blades with high-temperature steam passing through the condenser 1, and transfers the steam to a condenser 4. It condenses there and sends it to storage tank 5. In such a concentrator, if a large amount of heated steam is passed through the heat exchanger 2 when starting the device from room temperature, thermal stress will occur in the components of the heat exchanger, which will have an adverse effect on the concentrator. In the past, operators had to manually inject steam gradually to provide this. On the other hand, in recent concentrators, when the device is operated, the temperature of the heating system 6 including the heat exchanger 2 is controlled by a control valve according to a preset ramp signal as shown in FIG. The flow rate of 7 is gradually increased to prevent thermal stress from occurring in the heating system 6 including the heat exchanger 2. In addition, in FIG. 1, 8 is a control device, 8A
is a signal output from the blind eye to the control valve T, 3 is a flowmeter,
9A is a signal output from the flow meter to the control device 8';
A river temperature sensor, 10A is a signal output from the detector, 11 is a liquid level detector, 11A is a signal output from the detector, 12 is a flow control valve controlled by the signal 11A, 13 is a Pump 14 is a processing liquid tank. By the way, in the concentrating apparatus, a so-called batch process may be performed in which a plurality of processing liquid tanks are arranged in parallel and these tanks are sequentially connected to a concentrator for processing.

In such a case, the operation of temporarily stopping the apparatus, switching the processing liquid tank, and then restarting the apparatus is repeated. However, when the concentrator of the above control method is adopted for the above batch processing, even when the heat exchanger is in a sufficiently heated state, the heating steam flow rate control valve is set in advance from the fully closed state. A certain amount of time T is always required for the valve's relationship to reach the target value according to the ramp signal.

The present invention has been developed in view of these problems, such as when processing liquids in multiple tanks in a batch process using one concentrator. The present invention provides a control device for a heat exchanger in a concentrator that is particularly advantageous in cases where the temperature range up to the target temperature is divided into several temperature ranges, and the input temperature signal is In response to this, a stepped signal generation circuit is used that outputs a signal corresponding to the temperature range to which the temperature of the signal belongs, and the circuit is provided with a step signal that is detected from the processing liquid in the heater or concentrator as the overflow signal. The heating steam variable flow rate control valve is controlled by the output from the stepped signal generation circuit, thereby rapidly raising the temperature of the heat exchanger to the target temperature. It is in.

The present invention will be described below with reference to embodiments shown in the drawings.

The concentrator shown in FIG. 3a has substantially the same construction as that of the subsidiary shown in FIG. 1, except for the control device 21. -Thus, elements in FIG. 3a that are the same as in FIG. 1 are provided with the same reference numerals. The control device according to the present invention includes:
Set the temperature range up to the target temperature (boiling point temperature of the processing liquid) in several steps, e.g. 8, S40℃, 40pm○<02≦6000,
It is divided into temperature ranges such as 60q○<88 S80qo, 8pi0<OS boiling point temperature, and corresponding to the input temperature signal, the highest temperature in the temperature range to which the signal temperature belongs (for example, the input signal If the temperature of is 82, it is 60℃)
A step-like signal generation circuit 22 that outputs a signal corresponding to
A is input moment by moment, and the output 22A from the stepped signal generation circuit 22 is compared with the heating steam flow rate signal 9A by the deviation detection circuit 23, and the deviation amount 23A obtained there is proportionally and The flow rate control valve is controlled by the control signal 24A that is output as a result of integral calculation. Reference numeral 25 is a starting signal generator, and 25A is its signal. 3 shows the characteristics of the flow rate control valve T controlled by the control device according to FIG.

As can be understood from this characteristic diagram, the flow rate control valve 7 is
A flow rate relationship corresponding to the processing liquid temperature 8 is quickly reached in the concentrator 1. That is, for example, if the processing liquid temperature 8 in the concentrator 1 is 5000 at the time of starting the apparatus, that temperature signal is input to the stepped signal generation circuit 22, and corresponds to the overflow signal output from the circuit. A signal is output, which causes the flow rate control valve 7 to adjust to the 6000 heating equivalent function (
50%). At this time, the steam flow rate is
The amount of heat is sufficient to immediately raise the temperature of the treated liquid in the concentrator via the flow rate, and the flow rate is such that thermal stress does not occur in the heat exchanger (which is in a state of 50 qo). Thereafter, when the temperature of the processing liquid 3 exceeds 60 qo, the control valve 7's temperature increases to the 80°C heating equivalent function (75 qo), which is one step higher.
%), and as the temperature of the processing liquid 3 increases, the opening degree finally reaches the boiling point heating equivalent (100%). In addition, if the temperature a inside the concentrator 1 is 9 pi○ at the time of starting the device,
The opening degree of the control valve 7 is immediately adjusted to the boiling point heating equivalent function (100%
). Therefore, when starting the device, the heat exchanger 2
In this case, sufficient steam is supplied to the heat exchanger without causing thermal stress, and the temperature of the treated liquid in the concentrator 1 is rapidly raised. In the above embodiment, when starting the device, there is no means for warming up the entire heating system and removing the air in the pipes. However, in order to have this performed by the same control device, the control device 21 is required to control the device. A timer was incorporated to delay the start for a certain period of time, while a signal generation circuit was separately prepared to maintain the heating steam flow rate for warming up, and this was activated within the above-mentioned delayed time to produce the result shown in Figure 5. Flow characteristics can be obtained.

In FIG. 6, such a warming-up means is achieved by a child valve 7a arranged in parallel with the flow rate control valve 7. When the child valve 7a is used in this manner, it is not necessary to use a variable flow rate control valve as the child valve, and it may be a simple on-off valve. Further, although this child valve 7a is concerned with the delay time of the control described above, it may be allowed to continue to maintain the concerned state without being closed afterwards (see the one-dot chain line in Fig. 5). In such a case, the heated steam supplied to the heat exchanger 2 will have a flow rate that is the sum of the flow rate of the flow rate control valve 7 and the flow rate of the child valve 7a. Needless to say, it is sufficient to set the flow rate to a sufficient range within the range where the flow rate is.When the child valve 7a for warming up is disposed in this way, when designing the flow rate control valve 7a, it is necessary to set the flow rate to a wide range. Figure 7 shows another type of concentrator to which the present invention can be applied. , a circulation heating method in which a heat exchanger 2 is disposed in the heater, and the treated liquid in the concentrator 1 is introduced into the heater 26, heated there, and then returned to the concentrator 1 by a circulation pump 27. Therefore, in this device, the heat exchanger 2 is disposed inside the heater 26, and
Although the difference is that the temperature of the treated liquid in the concentrator 1 is detected instead of the temperature of the treated liquid in the heater 26 in which the heat exchanger 2 is housed, it is substantially the same as the apparatus shown in FIG. It does not change. In addition, if the processing liquid temperature is detected incorrectly, the heater 2
Of course, it does not matter if it is within 6. The control device according to the present invention is not limited to the above-mentioned embodiments, but can adopt various embodiments within the scope of the claims.

For example, in the characteristic diagrams in Figures 4 and 5 shown in the example in Figure 3, the temperature range up to the target temperature (boiling point temperature of the processing liquid) is 0.
, S40qo, 40qoku82 S60℃, 60ko00
3 S80℃, 80℃<84 ≦Boiling point was divided into four temperature ranges, but this was divided into 0, S30℃0, 30℃<82
Mi 40 pm 0, ......, 70℃<05 S80q0, 80
It may be divided into 7 stages such as °C<OB S90ko0, 90qo<07 ≦boiling point, or 0, S40qo, 4
0qo<82 S55o○, 560<03 S75℃,
The temperature ranges may be arranged at irregular intervals such as 75qo<84S boiling point. Further, the temperature width and the steam flow rate increase width do not always need to be at a constant ratio (for example, increased by 20% every 20 qo). Furthermore, in the embodiment shown in FIG.
However, since the flow control valve 7 of the present invention can be roughly controlled, this feedback is not necessarily required. Furthermore, in the embodiments shown in FIGS. 6 and 7, the heating steam flow rate is controlled between the control valve 7 and the child valve 7a.
Although the flow rate is detected from the main pipe before the flow is divided into the control valve 7 and the slave valve 7a, the flow rate is detected from the control valve 7 side branch pipe which is divided into the control valve 7 and the child valve 7a, and the control valve 7 is controlled by the detection signal. You can. As described above, the control device for the heat exchanger in the concentrator according to the present invention controls the steam flow rate corresponding to the temperature of the treated liquid in the heater or concentrator from the initial stage when starting the device. For example, in batch processing, when the processing liquid is already at a high temperature at the start of the device, the temperature of the processing liquid in the concentrator can be quickly raised to the boiling point temperature. Moreover, no thermal stress is generated in the heat exchanger.

[Brief explanation of drawings]

Figure 1 is a piping diagram showing a conventional concentrator, Figure 2 is a characteristic diagram showing the steam flow rate characteristics due to the control device, and Figure 3 a.
Figure 3b is a block diagram showing the control device of the heat exchanger, Figure 4 is a characteristic diagram showing the steam flow rate characteristics by the control device, Fig. 5 is a characteristic diagram showing the steam flow rate characteristics according to another embodiment, and Fig. 6
The figure is a piping diagram showing other examples of piping in the concentrator.
The figure is a piping diagram showing another concentrator. 1...Concentrator, 2...Heat exchanger, 3...
・Processing liquid, 7...Variable flow rate control valve for heating steam, 9.
...Flowmeter, 10...Temperature detector, 11...
...・Liquid level detector, 12... Supply liquid flow rate control valve, 21
, 21'... Control device, 22... Staircase signal generation circuit, 23... Deviation detection circuit, 24... Arithmetic circuit, 2
6... Heater, 27... Circulation pump. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7

Claims (1)

[Claims] 1. A staircase that divides the temperature range up to the target temperature into several temperature ranges and outputs a signal corresponding to the temperature range to which the temperature of the signal belongs in response to an input temperature signal. A stepwise signal generating circuit is used, and the temperature signal detected from the processing liquid in the heater or concentrator is momentarily input into the circuit as the temperature signal, so that the output from the stepwise signal generating circuit is 1. A control device for a heat exchanger in a concentrator, characterized in that the temperature of the heat exchanger is rapidly raised to a target temperature by controlling a variable flow rate control valve for heating steam. 2 The temperature range up to the target temperature is divided into several temperature ranges, and in response to an input temperature signal, a stepped signal generation circuit is used that outputs a signal corresponding to the temperature range to which the temperature of the signal belongs. Then, a temperature signal detected from the processing liquid in the heater or concentrator is momentarily inputted into the circuit as the temperature signal, thereby controlling the variable flow rate for heating steam using the output from the stepped signal generation circuit. A concentrator, comprising: a signal generating circuit that controls the valve, further includes a timer that delays the start of the control for a certain period of time, and maintains the flow rate control valve at a warming-up heated steam flow rate at least during the delay time; A control device for a heat exchanger in a concentrator, characterized in that a warming-up steam flow rate is maintained for a certain period of time at the beginning of startup, and then a steam flow rate corresponding to the temperature of the processing liquid is immediately supplied. 3 The temperature range up to the target temperature is divided into several temperature ranges, and in response to an input temperature signal, a stepped signal generation circuit is used that outputs a signal corresponding to the temperature range to which the temperature of the signal belongs. Then, a temperature signal detected from the processing liquid in the heater or concentrator is momentarily inputted into the circuit as the temperature signal, thereby controlling the variable flow rate for heating steam using the output from the stepped signal generation circuit. A timer is provided to control the valve and further delay the start of the control for a certain period of time, and an on-off valve is arranged in parallel to the flow rate control valve separately from the variable flow rate control valve, and the on-off valve is equipped with a signal generating circuit that opens the flow rate control valve at least during the delay time, and maintains the warming-up steam flow rate for a certain period of time at the beginning of the start-up of the concentrator, and then immediately increases the steam flow rate corresponding to the processing liquid temperature. 1. A control device for a heat exchanger in a concentrator, characterized in that the heat exchanger is supplied with.