JPH0630759B2 - Cyan waste liquid treatment device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a cyan waste liquid treatment apparatus that heats and holds a cyan waste liquid by heating steam in a pressure vessel and thermally hydrolyzes it.

(Prior Art) In this type of processing apparatus, management of the processing temperature and a predetermined time during the decomposition processing step largely depends on the processing capacity.

That is, regarding the treatment temperature, if the cyan waste liquid heated to a predetermined treatment temperature is kept in a pressure vessel having a heat retaining function, the temperature will inevitably decrease during the decomposition treatment process. A predetermined processing temperature is maintained by intermittently introducing heating steam into the inside.

As for the predetermined time, a timer or the like can perform the decomposition process for, for example, 3 hours.

However, when the temperature changes during the decomposition process, the temperature may temporarily fall below the guaranteed temperature, and the decomposition process performance is extremely deteriorated in the time range below the guaranteed temperature. On the other hand, since the decomposition processing time is uniformly set as described above, the processing time also includes the time equal to or lower than the guaranteed temperature, and the cyan waste liquid may not be decomposed sufficiently.

Also, by setting the processing temperature high, it is possible to stabilize the processing capacity of the cyan waste liquid, but the processing capacity does not increase in proportion to the increase in heating energy, and the energy efficiency drops extremely, resulting in Expense will increase significantly.

(Object of the invention) The object of the present invention is to achieve stabilization of the decomposition treatment capacity of cyan waste liquid and saving of fuel cost.

(Technical means for achieving the object) In order to achieve the above object, the present invention provides a temperature sensor for detecting the temperature of a cyan waste liquid, and a temperature detected by the temperature sensor is in a temperature range lower than the guaranteed temperature or higher than the guaranteed temperature. And a determination means for determining when the temperature becomes equal to or higher than a predetermined processing temperature and when the temperature becomes equal to or lower than the optimum processing lower limit temperature. And a closing signal transmitting means for transmitting a closing signal when a time point at which the temperature exceeds a predetermined processing temperature is detected, an integrating means for integrating only the time of the temperature equal to or higher than the guaranteed temperature after the start of the decomposition processing, and the integrating means And a signal transmitting means for transmitting a closed state lock signal to the actuator of the steam injection valve when the time reaches a predetermined time.

(Operation) The cyan waste liquid is thermally hydrolyzed into ammonia gas, formate salt and metal oxide by the high-temperature heating steam in the pressure vessel. During the decomposition process, the temperature is detected by a temperature sensor and the steam injection valve is opened / closed by the temperature detection so that the temperature is controlled to be as high as possible. Moreover, even if the temperature falls below the guaranteed temperature during processing, the time range is not integrated into the processing time, and the processing time is controlled by integrating only the time at a temperature higher than the guaranteed temperature with the processing time.

(Example) FIG. 1 is a schematic piping diagram of a cyan waste liquid treatment apparatus to which the present invention is applied. In FIG. 1, a pressure vessel 1 is connected with a preheating tank 3 via a liquid supply valve 2, and A next process tank, for example, a cooling tank 6 is connected via the drain valve 5. The preheating tank 3 is connected to a cyan waste liquid storage tank 10 via a liquid feeding pump 8. Nozzle type steam supply unit 4 is provided in the pressure vessel 1.
And the steam supply unit 4 is connected to a steam supply source 12 via a steam injection valve 11. The steam supply source 12 supplies heating steam having a temperature slightly higher than a predetermined processing temperature of 170 ° C. to the pressure vessel 1.

An ammonia gas absorption tank 14 is connected to the pressure vessel 1 via a gas vent valve 13. In this embodiment, the gas vent valve 13 is connected to the preheating tank 3 via the gas charging valve 15 so that the exhaust gas can be used as a heat source for the preheating tank 3. An actuator 23 for automatically opening and closing the gas vent valve 13, such as a hydraulic cylinder or a pneumatic cylinder, is connected to the gas vent valve 13.

In order to keep the inside of the pressure vessel 1 at a predetermined processing temperature as much as possible, the pressure vessel 1 is provided with a temperature sensor 20, and the steam injection valve 11 is provided with an actuator 21 for automatically opening and closing the temperature sensor 20, such as a hydraulic cylinder or pneumatic pressure. The cylinders are connected. Each actuator 21, 23
Is connected to the output of the controller 22, and the temperature sensor 20 is connected to the input of the controller 22.

FIG. 3 shows a block diagram of the control device 22. The control device 22 includes a discrimination means 31 for discriminating various ranges and time points of the temperature detected by the temperature sensor 20, a closing valve opening / closing signal transmission means 32, and an integration. Means 33, lock signal transmitting means 35 and the like are provided.

The discriminating means 31 discriminates whether the temperature range is lower than the guaranteed temperature (for example, 165 ° C.) or is the guaranteed temperature or more, and when the temperature reaches a predetermined processing temperature (170 ° C.) or more and Δt ° C. (about 1 ° C.) from the predetermined processing temperature. 〜2 ℃) Low optimum lower limit temperature (1
It has a function to determine the time when the temperature falls below 69 ° C or 168 ° C.

The steam injection valve opening / closing signal transmitting means 32 sends an open signal to the actuator 21 of the steam injection valve 11 when the determination means 32 detects a time point at which the temperature becomes equal to or lower than the optimum processing lower limit temperature, and determines the time point at which the processing temperature becomes equal to or higher than the predetermined processing temperature. Has a function of sending a closing signal to the actuator 21 when the steam injection valve 11 is detected.

The integrating means 33 has a function of integrating only the time in the temperature range equal to or higher than the guaranteed temperature during the decomposition process.

The lock signal transmission means 35 transmits a closed state lock signal to the actuator 21 of the steam supply valve 11 and an open signal to the actuator 23 of the gas vent valve 13 when the integration time by the integration means 33 reaches a predetermined time (3 hours). It has the function of transmitting.

Further, an abnormality warning device 50 is connected to the discrimination means 31, and an abnormality warning is issued by a lamp, a buzzer or the like when detecting a time point at which the temperature falls below the guaranteed temperature.

Further, an abnormal temperature time integration means 51 is connected to the determination means 31, and the integration means 51 sends a working signal to the abnormality alarm device 50 again when a temperature lower than the guaranteed temperature is integrated for a set time, for example, 30 minutes or more. have.

The cyan waste liquid treatment work will be described. A predetermined amount of the cyan waste liquid in the cyan waste liquid storage tank 10 shown in FIG. 1 is sent to the preheating tank 3 by the pump 8 and heated there to about 100 ° C.

The heated cyan waste liquid is sent from the preheating tank 3 into the pressure vessel 1 due to the level difference between the preheating tank 3 and the pressure vessel 1, for example.
The steam injection valve 11 is opened and heated to a predetermined processing temperature of 170 ° C. by the heating steam from the steam supply source 12.

When the temperature of the cyan waste liquid reaches 170 ° C, the steam injection valve 1
When 1 is once closed, the integrating means 33 in FIG. 3 starts to operate, and the decomposition process of the cyan effluent by thermal hydrolysis starts. The integration end time by the integration means 33 is set to 3 hours, for example. The cyan waste liquid is decomposed into ammonia gas, formate salts, metal oxides and the like by thermal hydrolysis during the decomposition treatment step.

In the decomposition treatment step, for example, as shown in FIG. 2, the temperature naturally decreases, but when it falls below the optimum lower limit temperature of treatment like point P1, it is judged by the judging means 31, and the signal injection means 32 causes the steam injection valve. An open signal is issued to the actuator 21 of No. 11, and the actuator 21 is actuated by the signal to open the steam injection valve 11, and the heating steam is injected into the pressure vessel. As a result, the temperature inside the pressure vessel 1 rises.

Then, when the temperature reaches a predetermined processing temperature of 170 ° C. like point P2, a closing signal is sent from the signal sending means 32 this time, the steam injection valve 11 is closed, and the temperature inside the pressure vessel 1 is prevented from rising excessively.

The automatic temperature adjustment as described above is repeated every time the temperature inside the container falls below the optimum processing lower limit, as indicated by point P3.

During normal operation, for example, as shown by the phantom line after P3 in FIG. 2, the opening / closing adjustment of the steam injection valve 11 keeps the temperature substantially within the range of the predetermined processing temperature and the optimum processing lower limit temperature. Then, when the processing time is added up and reaches a predetermined time of 3 hours,
A signal for locking the actuator 21 of the steam injection valve 11 in a closed state is sent by the signal transmitting means 35 shown in FIG. 3 and at the same time, an open signal is sent to the actuator 23 of the gas vent valve 13 so that the steam injection is performed. The valve 11 is locked in the closed state and the degassing valve 13 is opened.

However, during operation, due to abnormalities such as damage to the steam source (boiler) or piping, the processing temperature did not rise despite the opening of the steam injection valve, as shown by the solid line after P3 in Fig. 2. There is a case (point P4) when it falls further. In this case, it is determined that some abnormality has occurred, and the alarm device 50 issues an abnormality alarm, which is used as a guide for adjusting the defective portion. In this way, when a temperature lower than the guaranteed temperature occurs during the processing, the time range t1 lower than the guaranteed temperature shown in FIG. Only T1 and T2 are added up.
That is, when the total of T1 and T2 reaches the predetermined time of 3 hours
A signal for locking the actuator 21 of the steam injection valve 11 in a closed state is sent by the signal transmission means 35 of FIG. 3, and at the same time, an open signal is sent to the actuator 23 of the gas vent valve 13, whereby the steam injection is performed. The valve 11 is locked in the closed state and the degassing valve 13 is opened.

Further, when the state (t1) lower than the guaranteed temperature shown in FIG. 2 is accumulated by the accumulating means 51 for a set time (for example, about 30 minutes) or more, it may cause a delay in the entire cyan waste liquid treatment cycle. An alarm is issued by the alarm device 50. This alarm can be used as a guide for confirming the cause of the abnormality.

When the decomposition process is completed, the temperature of the decomposed processed liquid is lowered in the pressure vessel 1 to some extent, and then the drain valve 5 is opened to send the processed liquid to the cooling tank 6. Ammonia gas is a gas absorption tank 1
4 or the preheating tank 3 for preheating.

(Effects of the Invention) According to the present invention as described above: (1) In the decomposition treatment step by heating and holding in the pressure vessel 1, only the time of a temperature higher than the guaranteed temperature is integrated, and it is calculated as a predetermined treatment time. As a result, the processing capacity by the automation of the processing device becomes stable.

That is, since only the time during which the cyan waste liquid is sufficiently decomposed is integrated as the predetermined processing time, the predetermined time is always maintained regardless of the frequency or the size of the temperature decrease below the guaranteed temperature in the pressure vessel 1. The amount of cyan waste liquid can be decomposed sufficiently.

(2) When the temperature exceeds a predetermined processing temperature, the steam injection valve 11 is closed to prevent the temperature from rising excessively, so that energy is not wastefully consumed and fuel cost can be saved.

If an abnormality alarm device that issues an abnormality alarm signal when the temperature is lower than the guaranteed temperature is connected to the determination means, it will detect an abnormality in the steam input source (for example, boiler) or the steam piping system, and can be used as a guideline for maintenance. it can.

[Brief description of drawings]

FIG. 1 is a schematic diagram of the entire piping of a cyan waste liquid treatment apparatus to which the present invention is applied, FIG. 2 is a graph showing the temperature change of the cyan waste liquid during the decomposition treatment process, and FIG. 3 is a block diagram of each means in the control device. is there. 1 ... Pressure vessel, 2 ... Cyan waste liquid supply section, 11 ... Steam injection valve, 12 ... Heating steam supply source,
20 ... Temperature sensor, 21 ... Actuator, 22
...... Control device, 31 ...... Discrimination means, 32, 35 ...... Signal transmission means

Claims (2)

[Claims] 1. A temperature sensor for detecting the temperature of a cyan waste liquid in a cyan waste liquid treatment device, wherein a heating steam supply source is connected to a pressure vessel via a steam injection valve to heat-hold and thermally hydrolyze the cyan waste liquid. A determination means for determining whether the temperature detected by the temperature sensor is lower than the guaranteed temperature or higher than the guaranteed temperature, and at the time when the temperature is equal to or higher than the predetermined processing temperature and equal to or lower than the optimum processing lower limit temperature; An open / close signal transmission means that sends an open signal to the actuator of the steam injection valve when the temperature below the lower limit temperature is detected, and a close signal when the time above the predetermined processing temperature is detected, and the guaranteed temperature after the start of the decomposition process. An integrating means for integrating only the time of the above temperature, and a closed state lock signal to the actuator of the steam injection valve when the integrating time by the integrating means reaches a predetermined time. Cyanide decomposition treatment apparatus characterized by comprising a signal transmitter for transmitting. 2. The cyan decomposition processing device according to claim 1, further comprising an abnormality alarm device for issuing an alarm in a temperature range lower than the guaranteed temperature, which is connected to the discriminating means.