JP2020185559A - Liquid filter - Google Patents

Abstract

To provide a liquid filter which can reliably avoid entry of a process liquid into an air exhaust mechanism.SOLUTION: In a liquid filter 10, a liquid level detection mechanism 2 comprises: a main liquid level detection device 21 which can detect a flooded liquid state; and a sub liquid level detection device 22 which can detect a semi-flooded liquid state which is the state that the liquid level reaches a semi-upper limit at a lower position than an upper limit. The liquid level detection mechanism 2 has caution signal transmission means which transmits a caution signal to a control mechanism 6 at any time when the main liquid level detection device 21 detected the flooded liquid state and when a preset reference time has lapsed after the sub liquid level detection device 22 detected the semi-flooded liquid state. The control mechanism 6 has control means which causes each mechanism of the liquid filter 10 to perform a process liquid leakage prevention operation for preventing entry of the process liquid into an air exhaust mechanism 5 when receiving the caution signal.SELECTED DRAWING: Figure 1

Description

The present invention relates to a liquid filter. Specifically, the present invention presents the infiltration of the treatment liquid into the exhaust duct in a closed liquid filter typified by a continuous liquid filter or the like used in nickel smelting or the like using HPAL (high pressure sulfuric acid leaching) technology. It is a technology that more reliably prevents and imparts a high degree of safety to the liquid filter.

For example, in a hydrometallurgy process based on high pressure sulfuric acid leaching (HPAL: High Pressure Acid Leach) that recovers nickel from low-grade nickel oxide ore, the gas in the gas phase part is conventionally treated in a closed type treatment tank. A type of liquid filter equipped with an exhaust mechanism for discharging to the outside of the is widely used.

In a liquid filter having such a basic structure, usually, the liquid level of the treatment liquid in the treatment tank is detected, and while this is fed back to the control mechanism, other operations such as supply and discharge of the treatment liquid are sequenced. It is controlled. However, in the case of a liquid filter having the above structure, in the unlikely event that a malfunction such as a malfunction of the instrument that detects the liquid level occurs, the processing liquid will infiltrate into the exhaust mechanism and the operation will continue. There was a risk that it would be impossible, or that the function of the exhaust mechanism as an environmental smoke collecting facility would be impaired and harmful gas would leak to the outside of the factory.

In order to prevent the above-mentioned risk from becoming apparent, a waste liquid transfer device (see Patent Document 1) having a mechanism for detecting an abnormal inflow of waste liquid and stopping the operation of the pump as necessary, and an upper liquid level detector and a lower one. A filtration tank (see Patent Document 2) or the like having a liquid level detection unit and controlling the fluctuation of the water level of the filtered water as small as possible is used.

Japanese Unexamined Patent Publication No. 63-214388 Japanese Unexamined Patent Publication No. 2005-58970

However, in all the conventional control methods of the treatment liquid, the safety measures at the time of malfunction of the above-mentioned detector and the like are not always sufficient. In a liquid filter such as a "continuous liquid filter", even if a malfunction occurs in a device that detects the liquid level, it is possible to more reliably prevent the treatment liquid from entering the inside of the exhaust mechanism. There was a need for a technical means that could be done.

An object of the present invention is to provide a liquid filter capable of more reliably avoiding the infiltration of the processing liquid into the inside of the exhaust mechanism even when a malfunction occurs in the device for detecting the liquid level. To do.

In a liquid filter such as a continuous liquid filter, the present inventors have described the liquid level detection mechanism for detecting the upper limit of the liquid level as described below in two types of upper limit detection devices, main and sub, which have different functions. It has been found that the risk of the treatment liquid infiltrating into the inside of the exhaust mechanism can be remarkably reduced by the configuration according to the above, and the present invention has been completed. Specifically, the present invention provides the following.

(1) A liquid filter including a closed type treatment tank, a treatment liquid supply mechanism, a filtrate discharge mechanism, and an exhaust mechanism, and a liquid level for detecting the liquid level of the treatment liquid inside the treatment tank. The liquid level detection mechanism has a detection mechanism, a filtrate discharge mechanism, and a control mechanism for controlling the operation of the exhaust mechanism, and the liquid level detection mechanism detects a full state in which the liquid level has reached a specified upper limit. A possible main liquid level detecting device and a sub-liquid level detecting device capable of detecting a quasi-full liquid state in which the liquid level has reached a quasi-upper limit at a position lower than the upper limit are provided. The liquid level detection mechanism is a reference time set in advance when the main liquid level detecting device detects the full liquid state or after the sub liquid level detecting device detects the semi-full state. A caution signal transmitting means for transmitting a caution signal toward the control mechanism is provided at any time after the lapse of time, and the control mechanism enters the inside of the exhaust mechanism of the processing liquid when the caution signal is received. A liquid filter having a control means for causing each mechanism of the liquid filter to perform a treatment liquid leakage prevention operation for preventing the infiltration of the liquid filter.

(2) The liquid filter according to (1), wherein the treatment liquid leakage prevention operation includes an operation of opening the filtrate discharge mechanism to promote discharge of the filtrate from the treatment tank.

(3) The operation according to (1) or (2), wherein the treatment liquid leakage prevention operation includes an operation of closing the exhaust mechanism to prevent the treatment liquid from entering the inside of the exhaust mechanism from the treatment tank. Liquid filter.

(4) The liquid filter according to any one of (1) to (3), wherein a device for detecting the intrusion of liquid into the exhaust mechanism is installed.

According to the present invention, it is possible to provide a liquid filter capable of more reliably avoiding the infiltration of the processing liquid into the inside of the exhaust mechanism even when a malfunction occurs in the device for detecting the liquid level. it can.

It is sectional drawing which shows typically the structure of the liquid filter of this invention. It is a flowchart which shows the flow of the process liquid leakage prevention operation in the liquid filter of this invention.

Hereinafter, embodiments of the present invention will be described. However, the present invention is not limited to the following embodiments.

<Liquid filter>
The liquid filter 10 of the present invention is the same as the conventional closed type treatment tank, the treatment tank 1, the treatment liquid supply mechanism 3 for supplying the treatment liquid to the inside of the treatment tank 1, and the treatment after filtration to the outside of the treatment tank 1. The filtrate discharge mechanism 4 for discharging the liquid (filtrate) and the exhaust mechanism 5 for discharging the gas from the gas phase portion on the treatment liquid to the outside of the treatment tank are provided.

In addition to the above-mentioned basic configuration as a liquid filter, the liquid filter 10 of the present invention further includes a liquid level detection mechanism 2 having a configuration peculiar to the present invention and a caution signal transmitted from the liquid level detection mechanism 2. Correspondingly, a control mechanism 6 (not shown in FIG. 1, see FIG. 2) for controlling the operation of each mechanism provided in the liquid filter 10 is provided. Details of the functions of each mechanism will be described later.

[Processing tank]
The liquid filter 10 includes a closed type processing tank 1 that operates in a state where the gas phase portion is formed on the liquid surface of the liquid phase portion except when the processing liquid is filled. A filtration membrane (filter cloth) 11 is installed inside the treatment tank 1, and the treatment liquid (however, usually containing impurities as a solid substance; the same applies hereinafter) is continuously applied by the filtration membrane 11. A filtrate from which impurities have been removed can be obtained from the treatment liquid.

[Liquid level detection mechanism]
The liquid filter 10 includes a liquid level detection mechanism 2 having a configuration peculiar to the present invention. The liquid level detection mechanism 2 is a mechanism for detecting the liquid level of the processing liquid inside the processing tank 1, but it is a combination of two detection devices that independently detect the liquid levels specified at different heights. It is configured.

The main liquid level detecting device 21, which is one device constituting the liquid level detecting mechanism 2, is in a “full state” in which the liquid level of the processing liquid inside the processing tank 1 has reached a specified “upper limit”. It is a device that detects that. Here, the "full state" usually means a state in which the treatment liquid is filled up to the top of the treatment tank 1, but the "upper limit" of the liquid level that defines the "full state" is individual. The liquid level may be arbitrarily set according to the structure, function, or operating conditions of each liquid filter. As shown in FIG. 1, the main liquid level detecting device 21 is installed at a position where it can detect that the liquid level of the processing liquid has reached the "upper limit" and is in the "full state".

The sub-liquid level detection device 22, which is another device constituting the liquid level detection mechanism 2, detects that the liquid level in the processing tank 1 is in a predetermined “quasi-full state”. The "quasi-full state" in the present specification means the inside of the processing tank 1 at a predetermined "quasi-upper limit" predetermined at a position lower than the above-mentioned "upper limit" that defines the above-mentioned "full state". It refers to the state in which the liquid level of the treatment liquid has reached. The "quasi-upper limit" that defines the "quasi-full state" can be arbitrarily set according to the structure, function, or operating conditions of each liquid filter. As shown in FIG. 1, the sub-liquid level detection device 22 is installed at a position where it can detect that the "quasi-full state" has reached the "quasi-upper limit".

Then, of the above two detection devices, the sub-liquid level detection device 22 starts time measurement starting from the time when the "quasi-full state" is reached, in addition to the function of detecting the "quasi-full state". It has a time measuring means 221 such as various timers that can measure that a preset "reference time" has elapsed from the time when the "quasi-full state" is reached.

The liquid level detection mechanism 2 is preset when the main liquid level detection device 21 detects the "full state" and after the sub liquid level detection device 22 detects the "quasi-full state". It has a caution signal transmitting means for transmitting a "caution signal" to the control mechanism 6 at any time when the "reference time" of the above has elapsed. The details of the flow of the processing liquid leakage prevention operation to the exhaust mechanism 5 in which the operation of the liquid level detection mechanism 2 and the operation of the control mechanism 6 are performed in conjunction with each other will be described later.

It is preferable that the liquid filter 10 is further provided with a lower limit detection device 23 capable of detecting that the liquid level has reached the lower limit.

In addition, each of the above-mentioned detection devices (21 to 23) can be specifically configured by appropriately using various conventionally known liquid level detection devices such as a vibration type level switch.

[Treatment liquid supply mechanism]
In the liquid filter 10, the treatment liquid supply mechanism 3 for supplying the treatment liquid to the inside of the treatment tank 1 may have the same structure as the conventional liquid filter. The treatment liquid supply mechanism 3 includes, for example, a water inlet valve 31 and a treatment liquid inlet valve 32 that start or stop the supply of the treatment water and the treatment liquid.

[Sulfate discharge mechanism]
In the liquid filter 10, the filtrate discharge mechanism 4 for discharging the filtrate to the outside of the treatment tank 1 may have the same structure as that of the conventional liquid filter. The filtrate discharge mechanism 4 includes, for example, a filtrate outlet valve 41 and the like for starting or stopping the discharge of treated water and the filtrate.

[Exhaust mechanism]
In the liquid filter 10, the exhaust mechanism 5 for discharging gas from the gas phase portion of the treatment tank 1 to the outside of the treatment tank 1 includes an exhaust gas duct 51, an exhaust gas outlet valve 52, and the like. For example, in the continuous liquid filter used in the wet process of the nickel smelting process described above, the gas in the gas phase portion of the treatment tank 1 is exhausted through the exhaust mechanism 5, and the treatment liquid is discharged inside the treatment tank 1. It is filled. Further, in many cases, the exhaust mechanism 5 functions in conjunction with the environmental smoke collecting equipment of the entire plant.

Further, it is preferable that the exhaust mechanism 5 is provided with, for example, a liquid intrusion detection device 53 that detects the intrusion of the treatment liquid into the duct near the inlet on the side of the treatment tank 1 of the exhaust gas duct 51. As the liquid intrusion detection device 53, various conventionally known detection devices can be used, but a capacitance type or optical type wetness sensor or the like can be preferably used, whereby the liquid passes through the duct without being filled. It can also detect the liquid to be used.

[Control mechanism]
The control mechanism 6 infiltrates the processing liquid into the exhaust mechanism 5 in response to a "caution signal" received from the liquid level detection mechanism 2 composed of the main liquid level detection device 21 and the sub liquid level detection device 22. A control means for causing each mechanism of the liquid filter 10 to perform a "treatment liquid leakage prevention operation" for preventing the above. The control mechanism 6 may be any mechanism capable of exerting a function of controlling the operations of the processing liquid supply mechanism 3, the filtrate discharge mechanism 4, and the exhaust mechanism 5 in response to the above-mentioned "caution signal". The specific form of the control mechanism 6 is not particularly limited, but in an electronic control device such as a programmable logic controller (PLC) used for controlling the operation sequence of each mechanism in a general liquid filter, the present invention is used. The control mechanism 6 can be configured by operating a program programmed according to the original "control method of the liquid filter".

[Other mechanisms]
In addition, a spray water inlet valve 71, a nitrogen inlet valve 72, a backwash liquid inlet valve 73, a drain valve 74, and the like are installed in the liquid filter 10 as needed. For example, in the case of the above-mentioned continuous liquid filter, the filtered solid matter adhering to the filtration membrane 11 is the water supplied by the spray water inlet valve 71, the nitrogen inlet valve 72, the reverse cleaning liquid inlet valve 73, and / or. Alternatively, it is wiped off by nitrogen and discharged through the drain valve 74.

The liquid filter of the present invention described above is preferably implemented as a continuous liquid filter used in the nickel recovery process by the above-mentioned high-pressure sulfuric acid leaching (hereinafter, HPAL: High Pressure Acid Leach) as a representative example of a preferable embodiment. Can be mentioned. However, the present invention is not limited to this, and is a general liquid filter having a closed type processing tank having a liquid phase portion and a gas phase portion and having a mechanism for discharging gas from the gas phase portion as needed. Can be widely applied to.

<Control method for liquid filter>
FIG. 6 shows a control method capable of preventing the processing liquid from entering the inside of the exhaust mechanism 5 even when a malfunction occurs in the device for detecting the liquid level in the liquid filter 10 having the structure described above. This will be described with reference to 2.

In normal operation of the liquid filter 10, if the main liquid level detecting device 21 detects the "flooded condition", "caution signals S _1" is transmitted to the control mechanism 6. Control mechanism 6 that has received the attention signal S ₃ passing through the OR circuit (OR circuit), by opening the filtrate outlet valve 41 to the filtrate discharge mechanism 4 transmits a command for starting the discharge of the filtrate, the exhaust mechanism 5 , 52 is closed to send a command to stop the discharge of gas. In this state, the treatment liquid is continuously supplied to the inside of the treatment tank 1 by the treatment liquid supply mechanism 3, so that the filtration step is started and the filtrate is obtained through the filtrate outlet valve 41. As long as the main liquid level detecting device 21 is operating normally, each of the above commands also prevents the processing liquid from entering the inside of the exhaust mechanism 5. That is, in this case, the above-mentioned normal operation of the filtrate discharge mechanism 4 and the exhaust mechanism 5 performed by the command from the control mechanism 6 is the "treatment liquid leakage prevention operation".

On the other hand, in the liquid filter 10, when the sub-liquid level detecting device 22 detects the "quasi-full state", the "attention signal S ₂ " is first generated, and the duration of the "attention signal S ₂ " is measured by the time measuring means. Measure at 221. When no longer "JunMitsurueki state" and "CAUTION signal S _2" is gone, the duration back to zero. On the other hand, if the "quasi-full state" continues and the "caution signal S ₂ " is maintained, the "caution signal S ₂ '" is transmitted to the control mechanism 6 when the above-mentioned "reference time" has elapsed. Will be done. Also in this case, the control mechanism 6 which has received the attention signal S ₃ passing through the OR circuit (OR circuit) and transmits the same command to the filtrate discharge mechanism 4 and the exhaust system 5. Therefore, even when the main liquid level detection device 21 is not operating normally, the "processing liquid leakage prevention operation" is operated by the command from the control mechanism 6. In this way, by measuring the duration of the "caution signal S ₂ " with the time measuring means 221, it is possible to avoid improper operation of the control mechanism 6 when the liquid tends to decrease in the processing tank 1. , It can be easily configured without the need for a device for knowing the rate of increase / decrease in the liquid level.

The "treatment liquid leakage prevention operation" in the present specification is not limited to the specific operations related to the filtrate discharge mechanism 4 and the exhaust mechanism 5 described above. Lined according to the caution signal transmitted from the main liquid level detection device 21 immediately after the "full state" is detected and the caution signal transmitted from the sub liquid level detection device 22 after the reference time elapses after the "quasi-full state" is detected. Any operation that can actually prevent the processing liquid from entering the inside of the exhaust mechanism 5 is sufficient, and all the liquid filters 10 capable of performing such an operation are the techniques of the present invention. Included in the target range.

Further, as described above, when the liquid intrusion detection device 53 is installed in the exhaust mechanism 5 of the liquid filter 10, even when the liquid intrusion detection device 53 detects the intrusion of the processing liquid, the “Caution signal S” ₄ (not shown) ”can be transmitted to activate the“ processing liquid leakage prevention operation ”. However, in this case, an alarm with the sending of "attention signal S _4", besides, with the configuration to be installed an interlock that stops the supply of the processing liquid immediately in the liquid filter 10 The safety can be further enhanced. Further, depending on the degree of infiltration of the treatment liquid, measures may be taken to prevent the infiltration of the treatment liquid by opening the drain valve 74 or using other equipment connected to the environmental end smoke equipment.

1 Treatment tank 11 Filter membrane 2 Liquid level detection mechanism 21 Main liquid level detection device 22 Sub liquid level detection device 221 Time measuring means 23 Lower limit detection device 3 Treatment liquid supply mechanism 31 Water inlet valve 32 Treatment liquid inlet valve 4 Filtration discharge mechanism 41 Filtration outlet valve 5 Exhaust mechanism 51 Exhaust duct 52 Gas outlet valve 53 Liquid intrusion detection device 6 Control mechanism 71 Spray water inlet valve 72 Nitrogen inlet valve 73 Backwash liquid inlet valve 74 Drain valve 10 Liquid filter

Claims (4)

A liquid filter including a closed type treatment tank, a treatment liquid supply mechanism, a filtrate discharge mechanism, and an exhaust mechanism.
A liquid level detection mechanism that detects the liquid level of the treatment liquid inside the treatment tank, and
It has a filtrate discharge mechanism and a control mechanism for controlling the operation of the exhaust mechanism.
The liquid level detection mechanism reaches a main liquid level detecting device capable of detecting a full liquid state in which the liquid level has reached a specified upper limit, and a quasi-upper limit at which the liquid level is lower than the upper limit. It is equipped with a secondary liquid level detection device that can detect the semi-full state, which is the state of the product.
The liquid level detection mechanism is a reference time set in advance when the main liquid level detecting device detects the full liquid state or after the sub liquid level detecting device detects the semi-full state. It has a caution signal transmitting means for transmitting a caution signal toward the control mechanism at any time when
The control mechanism has a control means for causing each mechanism of the liquid filter to perform a treatment liquid leakage prevention operation for preventing the treatment liquid from entering the inside of the exhaust mechanism when the caution signal is received.
Liquid filter. The liquid filter according to claim 1, wherein the treatment liquid leakage prevention operation includes an operation of opening the filtrate discharge mechanism to promote discharge of the filtrate from the treatment tank. The liquid filter according to claim 1 or 2, wherein the treatment liquid leakage prevention operation includes an operation of closing the exhaust mechanism to prevent the treatment liquid from entering the inside of the exhaust mechanism from the treatment tank. The liquid filter according to any one of claims 1 to 3, wherein a device for detecting the intrusion of liquid into the exhaust mechanism is installed.

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