Apparatus and process for filter cake breakthrough detection

Abstract

A filtration apparatus can be configured to utilize a control system to detect sufficient dewatering of filter cake for facilitating quicker operation for improved output. Some embodiments can include a control device that can monitor pressure upstream and downstream of a pressurization fluid feed valve to detect a condition during pressurization of filter cakes for dewatering to indicate that sufficient dewatering has occurred for subsequent processing.

Description

APPARATUS AND PROCESS FOR FILTER CAKE BREAKTHROUGH DETECTIONFIELD

[0001] The present innovation relates to processes and apparatuses for filtration of solid particulates from a slurry and processes and apparatuses configured to detect that one or more filter cakes formed via a filtration process are sufficiently dewatered for further processing.BACKGROUND

[0002] Filtration for separation of solid media from a liquid can be performed via different types of filter devices, which can use filter media to help facilitate separation of the liquid from the solid particulates. Examples of such devices, filter media, and filtration processing can be appreciated from U.S. Patent Nos. 7,674,386, 7,011,741, 6,521,135, 6,491,817, 6,350,382, 6,159,359, 5,615,713, 5,573,667 5,236,601, 5,292,434, 5,059,318, and 4,145,288, as well as U.S. Pat. App. Pub. Nos. 2022 / 0379243, 2019 / 0336890, 2016 / 0250570, 2015 / 0343354, 2010 / 0096341, 2007 / 0256984, 2006 / 0283785, and 2006 / 0027509 and Japanese Patent Publication No. JP2004167446 A2.SUMMARY

[0003] In pressure filtration, pressurized air may be supplied to a slurry-filled filter in order to dry filter cakes. In horizontal plate-based filter presses (e.g. AFP automatic filter press offered by FLSmidth), pressure from a pump can be used to fill filter chambers and dewater the filter cakes to the maximum degree afforded by the pump's pressure. Compressed air may then be used to dry the filter cakes to a target moisture level, which is a step that is often called the cake blow or air blow. In vertical filter presses (e.g. the Pneumapress vertical filter offered by FLSmidth) a cake blow step may be used to dry filter cakes after their initial formation.

[0004] Some types of vertical filter presses, such as the Pneumapress vertical filter, can use compressed air for both the initial dewatering and the filter cake drying / air blow steps. We have found that, during filter cake drying or air blow, the incompressible liquid in the chamber can initially create a restriction of gas flow such that there may be a minimal difference in pressure between the compressed gas and the pressure downstream of a valve through which compressedgas can be fed to the filter press. We determined that this minimal difference in pressure may be a result of the incompressible liquid providing a restriction of flow to the compressed gas that is being fed to the filter to push the liquid out of a filter cloth while the filter cloth retains solid particulates of a slurry. We determined that this condition can exist even through there may be an outlet through which liquid in the slurry being filtered can be removed (e.g., an outlet that is kept at atmospheric pressure or other lower pressure so the liquid can be pushed through the filter media for being output form the filter device for filtration). For example, we determined that this type of condition can exist because the liquid in the slurry being filtered can restrict the flow of compressed gas through the filter cloth. This condition can permit the compressed gas to push the liquid through the filter cake even though there is not much, if any, compressed gas being passed through the filter cloth during this initial dewatering stage of filtration. A “wall” of liquid passing through the filter cloth functions to restrict the flow of the compressed gas passing through the filter cloth.

[0005] We determined that once the compressed air forces the liquid of the slurry through the filter cloth, it can “break through” the filter cake. At the “breakthrough” event, there can be a significant pressure difference between the pressure of the compressed gas upstream of its feed valve and the pressure that may be detected downstream of the feed valve We have determined that at this “cake breakthrough” condition, the filter cakes are not completely dry because there is still residual moisture that can be reduced with further air blow. However, we have further determined that the initial “wall” of water (that can prevent the pressure from changing substantially) can be a condition that can be detected via the pressure difference that may be present between positions that are upstream and downstream of a compressed gas feed valve.

[0006] Previous to cake breakthrough, almost no compressed air may be consumed (e.g. only enough compressed air may be supplied to the filter to fill its filter chambers for pressurizing the filter chambers for acting on the filter cakes) to remove the “wall” of water, which can represent the bulk of remaining cake moisture. After the cake breakthrough, we determined that compressed air can flow through the filter cake and to the chamber outlet at a much higher rate. This may reduce the rate of cake moisture reduction and require far more air usage, leading to inefficient filtration efficiency after cake breakthrough. Filter operators can have an optimal filter cake moisture level they are targeting to try and maximize throughput or product quality. Wehave recognized that use of too much filter cake drying could move the final filter cake moisture level away from this optimal point, consume more compressed air than necessary, and cause a regular disturbance of compressed air loudly blowing through the filter. Also, use of too little filter cake drying can also cause problems by providing a filter cake that is too wet to meet process requirements and can pose other processing problems.

[0007] Conventionally, we do not believe there is a way to detect when a cake breakthrough condition occurs. For instance, in the operation of the Pneumapress vertical filter, there is no distinction between the initial dewatering and filter cake drying steps since they are typically involved in a continuous application of compressed air to the filter cakes. The duration of the application of compressed air is set to a fixed time value manually during filter commissioning.

[0008] This type of processing scheme can result in a number of problems that we have recognized. For example, a filter cake's target moisture level may correspond with the cake breakthrough, and conventional processing can result in non-detection of when this occurs. As a result, the filter cakes formed can be over-dried. Conventional processing can also result in the overall output capacity of the filter being lower than it otherwise could be. This can have a significant impact on the overall operational flexibility and production output for a filter device.

[0009] We have determined that being able to detect a cake breakthrough condition can better allow for filter cake formation to result in filter cake having a moisture content that is at, or closer to, a desired moisture content setpoint for the filter cake drying process. This can permit more consistent filter cake moisture levels for produced filter cakes as compared to use of a predetermined set filtration cycle time (that may be, at best, an educated guess as to what a combined time may be actually needed for adequate cake dewatering and drying). Such a set filtration cycle time may be a specific time that is estimated to be a time for adequate dewatering for applying compressed gas to the filter to filter the solid particulates and subsequently air blow the filter cake formed on the media. Some embodiments can avoid use of such guessing to provide improved operational performance while also permitting faster cycle times that provide filter cake output that has a more precisely controlled moisture content. The improved consistency in moisture content of the formed filter cakes can facilitate improved moisture content consistency, which can result in providing higher quality output.

[0010] Also, in situations where filter cake washing may occur after a filter cake is formed, the amount of cake drying beyond breakthrough is almost entirely wasteful as a redundant use of compressed air will be needed (post-washing), since the dried filter cakes will immediately be rewetted with a cleaning solution during the washing. Conventionally, after cleaning, the filter cakes may be redried, again. This illustrates how the over-drying of filter cakes can have a significant impact of efficient operation of a filter and also incur a significant waste of power and other resources in use of compressed gas for the drying that often over dries the filter cakes. In addition to increased use of power and compressed gas, the delays associated with the over drying reduces the overall production output of the filter as well.

[0011] We have determined that embodiments of a filer apparatus and control system, as well as processes for filtering and controlling a filtration apparatus can address over drying of filter cake issues. Embodiments can provide a significant reduction in time used for filter cake drying while also providing a more uniform application of filter cake drying so that the moisture levels in a dried filter cake are more consistently at a pre-selected or desired moisture content level. Embodiments can permit improved operational flexibility, increased production capacity, use less power and compressed gas, and may also provide other related benefits (e.g. reduced maintenance and maintenance down times, etc.).

[0012] In some embodiments, a valve can be utilized in conjunction with the air inlet header through which compressed air can be fed into the filter device’s chambers for dewatering and / or drying. Pressure sensors can be positioned on opposite sides of the valve to monitor the pressure differential across the valve between the pressures at those locations. When compressed air is initially supplied to the filter chambers, the upstream and downstream pressure sensors may read the same pressure or a similar pressure since the flow of compressed air is low during dewatering until the cake breakthrough condition occurs. Once cake breakthrough occurs, the flow of compressed air can drastically increase and the flow restriction created by the valve can result in a pressure differential between the upstream and downstream pressure sensors exceeding a preselected threshold that can be selected to detect the cake breakthrough condition. Once this pressure differential is detected as being at or above the selected threshold value, the supply of compressed air can be stopped (e.g. immediately stopped, or stopped after a short designatedinterval of time after detection) to avoid unnecessary cake drying and / or overuse of compressed air.

[0013] Some embodiments may utilize a control valve or modulating valve. In some embodiments, the pressure sensors that are on opposite upstream and downstream sides of the valve can be communicatively connected to a controller to control the position of the control valve based on the differential between the pressures detected. Position of the control valve may be determined, for example, via the data of the pressure sensors that can be communicated to the controller. A pre-selected threshold for the pressure differential can be a suitable pressure differential that corresponds to a cake breakthrough condition (e.g. a pressure difference of at least 0.05 kPa, a difference in pressure of 1% or greater than 1%, a difference in pressure of 5% or greater than 5%, a difference in pressure of greater than 10%, a difference in pressure of greater than 20%, a difference in pressure of greater than 40%, a difference in pressure of between 5% and 100%, or other suitable value, without limitation).

[0014] Embodiments can be configured so that redundant or excessive cake drying can be avoided and overuse of compressed air can also be avoided. This can help reduce the overall operational expense, and cycle time, which can significantly increase the throughput for a filter device. Also, this can result in a reduction in greenhouse gas emissions associated with the use of the power for operation of the filter device. It may also provide improved operational flexibility while also permitting a more reliable production of filter cakes having a desired moisture content. Further, embodiments can be configured to adapt to different filtering conditions that may exist without having those conditions negatively affect filter cake formation or moisture content of the formed and discharged filter cake. Such improvement in providing filter cakes with a desired moisture content can significantly improve the quality of the filter cakes formed via operation of a filter device while also improving the reliability of the operation of the device.

[0015] A filtration apparatus for separation of solid particulates from a slurry comprising liquid and the solid particulates can be provided. Embodiments of the filtration apparatus can include a plurality of moveable plates that are adjustable from closed positions to open positions and moveable filter media positioned between immediately adjacent plates such that slurry is positionable on the filter media when the plates are in their closed positions to separate the solidparticulates from the liquid for forming filter cake on the filter media, the filter media being moveable when the plates are in their open position to discharge the filter cake. A compressed gas feed line can be in fluid communication with the plates to feed compressed gas into cavities defined when the plates are in their closed positions. The compressed gas feed line can have a first valve that is adjustable between an open position and a closed position. The first valve can be positioned so that when the first valve is in the open position, compressed gas from a source of compressed gas that is connectable to the compressed gas feed line is feedable to the cavities when the plates are in their closed position, and the compressed gas is stopped from being passable into the cavities when the first valve is in the closed position. A first pressure sensor can be positioned to detect a pressure of the compressed gas feed line at a location that is upstream of the first valve and a second pressure sensor can be positioned to detect a pressure of the compressed gas feed line at a location that is downstream of the first valve in a downstream portion of the compressed gas feed line that extends from the first valve to the plates for feeding the compressed gas to the cavities. A controller can be communicatively connected to the first pressure sensor and the second pressure sensor to detect a pressure differential between (a) the pressure of the compressed gas feed line at the location that is upstream of the first valve and (b) the pressure of the compressed gas feed line at the location that is downstream of the first valve to detect a cake breakthrough for closing of the first valve.

[0016] The controller can be a type of control device. For example, the controller can include a processor communicatively connected to a non-transitory memory. The controller can also be communicatively connected to the first valve. The controller can also include other hardware and be communicatively connected to other elements. In some embodiments, the controller can be communicatively connected to the first valve to actuate adjustment of the first valve in response to detection of the cake breakthrough.

[0017] In some embodiments, the compressed gas feed line can have a second valve that is adjustable between an open position and a closed position. The second valve can be positioned downstream of the first valve. For example, the second valve can be positioned between the first valve and the second pressure sensor and the first valve can be positioned between the first pressure sensor and the second valve. The controller can be communicatively connected to the first valve and / or the second valve to actuate adjustment of the first valve and / or the secondvalve in response to detection of the cake breakthrough. In some embodiments, the first valve can be a modulating valve and the second valve is a control valve. In other embodiments, the first and second valves can be other types of suitable valves.

[0018] The filter media can be comprised of filter cloth in some embodiments. In other embodiments, the filter media can include filter membrane material or other suitable filter media..

[0019] The filtration apparatus can be configured as a type of filter device. For example, embodiments of the filtration apparatus can be configured as a vertical filter press or other type of filter press.

[0020] A control system for a filtration apparatus is also provided. Embodiments of the control system can include a first pressure sensor positioned to detect a pressure of a compressed gas feed line that is positioned at a location that is upstream of a first valve of the compressed gas feed line. A second pressure sensor can be positioned to detect a pressure of the compressed gas feed line at a location that is downstream of the first valve in a downstream portion of the compressed gas feed line that extends from the first valve to a plurality of plates in their closed positions for feeding the compressed gas into cavities defined by the plates that have moveable filter media positioned therein such that slurry is positionable on the filter media to separate the solid particulates from the liquid for forming filter cake on the filter media. A controller can be communicatively connected to the first pressure sensor and the second pressure sensor to detect a pressure differential between (a) the pressure of the compressed gas feed line at the location that is upstream of the first valve and (b) the pressure of the compressed gas feed line at the location that is downstream of the first valve to detect a cake breakthrough for closing of the first valve. The controller can include a processor communicatively connected to a non-transitory computer readable medium.

[0021] In some embodiments of the control system, the controller is communicatively connected to the first valve to actuate adjustment of the first valve in response to detection of the cake breakthrough.

[0022] In some embodiments of the control system, the compressed gas feed line can have a second valve that is adjustable between an open position and a closed position wherein thesecond valve is positioned downstream of the first valve. The second valve can be positioned between the first valve and the second pressure sensor and the first valve can be positioned between the first pressure sensor and the second valve. The controller can be communicatively connected to the first valve and the second valve to actuate adjustment of the first valve and the second valve in response to detection of the cake breakthrough.

[0023] A process for filtration is also provided. Embodiments of the process for filtration can include feeding slurry into cavities defined by immediately adjacent plates of a filtration apparatus in a closed position for filtration of the slurry to form filter cakes, pressurizing the cavities for dewatering of the filter cakes, detecting a pressure differential based on pressure data from a first pressure sensor and pressure data from a second pressure sensor to identify a cake breakthrough via the pressure differential exceeding a pre-selected threshold, and opening the plates to discharge the filter cakes after the cake breakthrough is identified.

[0024] Embodiments of the process can also include other steps or other features. For example, the pressurizing of the cavities for dewatering of the filter cakes can include feeding compressed gas into the cavities via a compressed gas feed line. The first pressure sensor can be positioned to detect a pressure of the compressed gas feed line upstream of a first valve of the compressed gas feed line and the second pressure sensor can be positioned to detect a pressure of the compressed gas feed line at a location that is downstream of the first valve in a downstream portion of the compressed gas feed line that extends from the first valve for feeding the compressed gas into the cavities.

[0025] Each of the cavities can have filter media positioned therein for draining of liquid from the slurry so a filter cake is formable on the filter media.

[0026] The process can also include other steps. For instance, in response to detection of the cake breakthrough, the first valve can be closed. The closing of the first valve can occur after a pre-selected post cake breakthrough drying time period has passed after the cake breakthrough was detected.

[0027] In some embodiments, the detecting of the pressure differential based on the pressure data from the first pressure sensor and the pressure data from the second pressure sensor to identify the cake breakthrough via the pressure differential exceeding the pre-selected thresholdcan be performed by a controller that is communicatively connected to the first pressure sensor and the second pressure sensor.

[0028] In some embodiments, the process can include closing the first valve in response to the identification of the cake breakthrough, passing a cleaning fluid to the cavities, pressurizing the cavities for dewatering of the filter cakes after the passing of the cleaning fluid to the cavities, and detecting a pressure differential based on the pressure data from the first pressure sensor and the pressure data from the second pressure sensor to identify the cake breakthrough via the pressure differential exceeding a pre-selected threshold after the cleaning fluid is passed to the cavities. The opening of the plates to discharge the filter cakes after the cake breakthrough is identified can be performed after the filter cakes are cleaned via the cleaning fluid and the cake breakthrough is identified after the cleaning fluid is passed to the cavities.

[0029] In some embodiments, the compressed gas is compressed air. Other embodiments may utilize another type of compressed gas.

[0030] Other details, objectives, and advantages of a filtration apparatus, control device for a filter press, process of filtration, process of detecting sufficient filter cake dewatering, control system, and methods of making and using the same will become apparent as the following description of certain exemplary embodiments thereof proceeds.BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Exemplary embodiments of our filtration apparatus, control device for a filter press, process of filtration, process of detecting sufficient filter cake dewatering, control system, and methods of making and using the same are shown in the drawings included herewith. It should be understood that like reference characters used in the drawings may identify like components.

[0032] Figure 1 is a schematic diagram of a first exemplary embodiment of a filtration apparatus 1 with plates 4 of the apparatus in a closed position. This embodiment of the filtration apparatus 1 also includes an exemplary embodiment of a control system.

[0033] Figure 2 is a schematic diagram of the first exemplary embodiment of the filtration apparatus 1 with plates 4 of the apparatus in an opened position.

[0034] Figure 3 is a flow chart illustrating a first exemplary embodiment of a process for filtration, which can utilize an exemplary embodiment of a process for detection of sufficient filter cake dewatering.

[0035] Figure 4 is a schematic illustration of an exemplary embodiment of a filtration module of a filtration apparatus in which the immediately adjacent plates are in a closed position for formation of a filter cake thereon in a state in which the pressurized gas is not yet being fed into the filtration modules of the apparatus.

[0036] Figure 5 is a schematic illustration of the exemplary embodiment of the filtration module of a filtration apparatus similar to that shown in Figure 4 in which the pressurized gas is being fed into the filtration modules of the apparatus to separate liquid from the particulates of the slurry to form filter cake on filter media within the closed filtration module.

[0037] Figure 6 is a schematic illustration of the exemplary embodiment of the filtration module of a filtration apparatus similar to that shown in Figures 4 and 5 in which the pressurized gas is being fed into the filtration modules of the apparatus to separate liquid from the particulates of the slurry to form filter cake on filter media within the closed filtration module wherein further liquid has drained from the module via the application of the pressurized gas as compared to Figure 5.

[0038] Figure 7 is a schematic illustration of the exemplary embodiment of the filtration module of a filtration apparatus similar to that shown in Figures 4-6 in which the pressurized gas is being fed into the filtration modules of the apparatus to separate liquid from the particulates of the slurry to form filter cake on filter media within the closed filtration module wherein the filter cake has further consolidated on the filter media and further liquid has drained from the module via the application of the pressurized gas as compared to Figure 6.

[0039] Figure 8 is a schematic illustration of the exemplary embodiment of the filtration module of a filtration apparatus similar to that shown in Figures 4-7 in which the pressurized gas is being fed into the filtration modules of the apparatus to separate liquid from the particulates of the slurry to form filter cake on filter media within the closed filtration module wherein the filter cake is more consolidated and further liquid has drained from the module via the application of the pressurized gas as compared to Figure 7.

[0040] Figure 9 is a schematic illustration of the exemplary embodiment of the filtration module of a filtration apparatus similar to that shown in Figures 4-8 in which the pressurized gas is beingfed into the filtration modules of the apparatus to separate liquid from the particulates of the slurry to form filter cake on filter media within the closed filtration module wherein further liquid has drained from the filter cake via the application of the pressurized gas as compared to Figure 8.

[0041] Figure 10 is a schematic illustration of the exemplary embodiment of the filtration module of a filtration apparatus similar to that shown in Figures 4-9, in which the pressurized gas is being fed into the filtration modules of the apparatus to separate liquid from the particulates of the slurry to form filter cake on filter media within the closed filtration module wherein further liquid has drained from the filter cake via the application of the pressurized gas as compared to Figure 9.

[0042] Figure 11 is a schematic illustration of the exemplary embodiment of the filtration module of a filtration apparatus similar to that shown in Figures 4-10, in which the pressurized gas is being fed into the filtration modules of the apparatus to perform a blowdown operation to further dry the filter cake formed on the filter media to provide a filter cake with a desired level of moisture.DETAILED DESCRIPTION

[0043] Referring to Figures 1-11, a filtration apparatus 1 can include a base 2 that supports a plurality of moveable plates 4 between open positions and closed positions. The open position of the filtration apparatus 1 can be a position in which the plates 4 are spaced apart from each other so each immediately adjacent plate 4 has a gap 4g between the immediately adjacent plates. The closed position of the filtration apparatus 1 can be a position in which the plates 4 are positioned in close proximity to each other to form filter cakes within a cavity defined between the immediately adjacent plates 4. In some embodiments, the closed position can be a position in which immediately adjacent plates are in air-tight proximity or engagement with each other, for example.

[0044] The base 2 can include one or more legs 3 or other type of support structure for supporting the filtration apparatus on a floor or the ground. The base 2 can also include other features to provide support to the moveable plates 4 and for operation of the filtration apparatus 1. At least one discharge chute 15 can be positioned on a discharge side of the filtration apparatus. In some embodiments, the filtration apparatus 1 can be configured as filter press, a vertical filter press, a vertical tower press filter, or other type of filtration device.

[0045] The plates 4 of the filtration apparatus can include a plurality of plates 4 that have a topmost plate 4t, a bottommost plate 4b, and at least one intermediate plate 4i positioned between the topmost plate 4t and the bottommost plate 4b. In some embodiments, there may be between 8 and 20 intermediate plates. Other embodiments may have more than 20 intermediate plates or less than 8 intermediate plates 4i.

[0046] Each filter cake defining module, which can be defined by two immediately adjacent plates 4, can include at least two pulleys 8 along which a filter media 7 extends. The filter media 7 can be a filter cloth (e.g. multifilament or monofilament belt filter cloth, filter press cloth, other type of filter cloth, etc.) or a type of filter membrane that can be configured as a continuous sheet that has a first end positioned around a first pulley 8 and a second end opposite the first end that is positioned around a second pulley. A first pulley 8 can be coupled to a drive mechanism that can rotate at least the first pulley 8 to drive motion of the filter media in a continuous motion around the first pulley 8 and the second pulley 8. There can also be one or more guides positioned to contact the filter media as the filter media is moved to keep the filter media in tight engagement for movement via the rotation of at least one of the pulleys 8.

[0047] The filter media can be a filter cloth or other type of filter media (e.g. a membrane, etc.) that can receive a liquid slurry having solid particulates therein. The filter media can be configured so that the liquid of the slurry may pass through the filter media 7 and the solid particulates can be retained on the filter media 7 to form a filter cake 13 on the filter media 7. The filter cake 13 can be an agglomeration of the solid particulates that are retained on the filter media after the liquid is passed through the filter media 7. After the filter cake 13 is formed and sufficiently dried, the filtration apparatus 1 can be moved to its open position and the formed filter cakes can be moved for being discharged into the chute(s) 15. For instance, one or more of the pulleys 8 can be moved to cause the filter media 7 to move along the pulleys about which the filter media is wrapped to cause the filter cakes 13 to be discharged into the chute(s) 15 as shown via arrows in Figure 2. Such motion also results in another portion of the filer media 7 being positioned so that it will be within the cavity when the plates 4 are again closed to filter more slurry and form more filter cakes in another operational cycle.

[0048] For example, when the plates 4 are in their closed positions, liquid slurry can be fed into the chambers defined by immediately adjacent closed cavities via a slurry feed conduit 6 that isin fluid communication with these cavities. The slurry feed conduit 6 can be connected to a feed valve 5f through which the slurry feed conduit 6 can receive slurry from a slurry feed conduit 5 that is connected to a source of the slurry (e.g. a tank that retains slurry, etc.). The slurry feed conduit 6 can also, in some embodiments, be connected to a slurry recirculation conduit 5r that can feed recirculated slurry to the slurry feed conduit 6 as well. Such recirculated slurry can be liquid that has been drained from the filtration apparatus 1 while it is in the closed position to form filter cakes, for example.

[0049] After the liquid slurry is fed into the closed chambers, or cavities, defined by immediately adjacent plates 4 in their closed positions, a compressed gas can be fed into the cavities to push the liquid through the filter media to be drained away from the solid particulates and form the filter cakes 13. For example, a source of compressed gas can be air that is fed from a compressed gas feed line 9 that is in fluid communication with the cavities of the closed plates 4 and the source of the compressed gas. The compressed gas can be fed to the filtration apparatus 1 via at least one compressor, which can compress air and feed the compressed air to the cavities of the closed plates via the compressed gas feed line 9, for example. The compressed gas can alternatively (or also) be provided via a compressed gas storage vessel that is in fluid communication with the compressed gas feed line 9.

[0050] The compressed gas feed line 9 can include a compressed gas header line, for example. The compressed gas feed line 9 can be a conduit that includes a first valve FV115 through which the compressed gas is passable for being fed to the cavities of the closed plates 4. Some embodiments can include a second valve FV114 that can be positioned downstream of the first valve FV115 to help provide additional isolation between the filtration apparatus 1 and the source of the compressed gas. A downstream portion 10 of the compressed gas feed line can extend from the second valve FV114 to the plates 4 for feeding compressed gas to the cavities defined by the immediately adjacent plates 4 when the plates are in their closed positions. The second pressure sensor PSI 16 can be connected to the downstream portion 10 of the compressed gas feed line to measure or detect the pressure of the compressed gas in this downstream portion 10 of the compressed gas feed line 9, which is downstream of the first valve FV115 and can also be downstream of the second valve FV114 (when also utilized). The second pressure sensor PS 116 can be positioned so it is downstream of the valve(s) V (e.g. first valve FV 115 and / orsecond valve FV114) and also be upstream of the plates 4 and / or compressed gas feed inlets for the filtration modules of the apparatus.

[0051] In some embodiments, the first valve FV115 can be a modulating valve V and the second valve FV114 can be a control valve V. In other embodiments the first valve FV115 can be a control valve V or other type of valve V and the second valve FV114 may not be utilized.

[0052] The compressed gas feed line 9 can include at least one conduit segment that includes the valves. The compressed gas feed line 9 may also include other flow control elements or sensors (e.g. a flow sensor, etc.).

[0053] The compressed gas feed line 9 can be structured as a conduit that includes piping or tubing for conveying the compressed gas. For example, the compressed gas feed line 9 can include welded segments of pipe or tube, or pipe or tube that are mechanically fastened together, for example.

[0054] A first pressure sensor PSI 17 can be positioned upstream of the first valve FV 115 such that the first valve FV 115 is between the first pressure sensor PSI 17 and a second downstream pressure sensor PSI 16. In embodiments that can utilize the second valve FV114, the second downstream pressure sensor PSI 16 can be positioned downstream of this second valve so that the first and second valves FV115 and FV114 are both between the first and second pressure sensors PSI 17 and PSI 16. In other configurations that may utilize the first and second valves, the second valve FV114 can be positioned downstream of the second pressure sensor PSI 16 so that the second pressure sensor PS 116 is between the first valve FV 115 and the second valve FV114.

[0055] After the slurry is fed to the cavities while the filtration apparatus 1 is in its closed position, the slurry feed valve 5f can be closed and the compressed gas valve(s) (e.g. first valve FV115 and / or, when utilized, second valve FV114) can be moved to an open position so that compressed gas can be fed into the cavities. The compressed gas can be fed until the pressure of the cavities is at a similar pressure (e.g. the same pressure or within + / - 5% of the same pressure) as the pressure of the source of the compressed gas. Liquid of the slurry can pool on the filter media 7 during this time and block further passage of compressed gas. Once the liquid starts to pass through the filter media 7, the pressure can change greatly as the pressure of the cavities at the inlet at which it receives the compressed gas can be lowered to the pressure at an outletthrough which liquid is to drain from the cavity, and the higher pressure compressed gas is able to also pass through the inlet and outlet of the cavity or cavities. Such an operational condition can be considered a “cake breakthrough” or a “breakthrough” condition. We have determined that at this “cake breakthrough” condition, the filter cakes 13 are not completely dry because there is still residual moisture that can be reduced with further compressed gas blow, but the initial “wall” of liquid that can create a pressure differential between the cavity inlet and outlet has been forced out of the filter cake 13.

[0056] Prior to this cake breakthrough condition occurring, almost no compressed gas fed to the cavities of the closed filtration apparatus 1 may be consumed (e.g. only enough compressed gas may be supplied to cavities defined by the immediately adjacent and closed plates 4 for pressurizing the cavities for acting on the filter cakes 13 to remove the “wall” of liquid, which can represent the bulk of remaining filter cake moisture.

[0057] Prior to the cake breakthrough event occurring, the pressure of the compressed gas measured by the first pressure sensor PSI 17 and the second pressure sensor PSI 16 can be the same or can be substantially the same (e.g. be the same, be within + / - 3% of each other, or be within + / - 5% of each other). For example, there may only be a slight differential in pressure that may be detected via those sensors prior to the cake breakthrough condition occurring during a filtration cycle while the filtration apparatus 1 is in its closed position. After the cake breakthrough condition has occurred, the pressure difference between the pressure measured, or detected, by the first pressure sensor and the pressure measured, or detected, by the second pressure sensor can be substantial (e.g. greater than 5% different, greater than 10% different, etc.).

[0058] For example, the pressure of the downstream portion 10 of the compressed gas feed line 9 that is detected or measured by the second pressure sensor PSI 16 can be the same or can be less than the pressure detected or measured by the first pressure sensor PSI 17 that is upstream of the first valve FV115. When this pressure differential exceeds a pre-selected threshold (e.g. a pre-selected cake breakthrough threshold), the cake breakthrough condition can be detected. This can indicate that the filter cakes 13 are mostly dry for meeting a pre-selected moisture content criteria for the filter cakes 13. The pre-selected threshold can be a suitable pressure threshold for a particular embodiment. In some embodiments, the pre-selected threshold cancorrespond to a pressure difference greater than 1%. For example, in some embodiments the pre-selected threshold may correspond to a pressure difference greater than or equal to 5% of the pressure detected by the first upstream pressure sensor, a difference in pressure of greater than or equal to 10% of the pressure detected by the first upstream pressure sensor, a difference in pressure of greater than or equal to 20% of the pressure detected by the first upstream pressure sensor, a difference in pressure of greater than or equal to 40% of the pressure detected by the first upstream pressure sensor, or other suitable value for defining the pre-selected threshold. In some embodiments, the pre-selected threshold may correspond to a pressure difference which is greater than approximately 1% but less than 100%, without limitation. The value can be defined as a pre-defined value or as a value that defines a deviational difference between the pressure sensed by the first upstream pressure sensor PSI 17 and the pressure sensed by the second downstream pressure sensors PSI 16.

[0059] A controller CTRL can be communicatively connected to the first and second pressure sensors PSI 17 and PSI 16 as well as the first valve FV115 and (when utilized) the second valve FV114. The controller CTRL can receive the pressure measurement data from the first and second pressure sensors PSI 17 and PSI 16 and determine the pressure differential that is indicated by those sensors. When the detected pressure differential corresponds to the preselected pressure differential threshold (e.g. is at the threshold or is greater than the threshold), the controller CTRL can communicate with the first valve FV115 and / or second valve FV114 to close one or both of those valves so that no more compressed air is fed to the filtration apparatus. The closing of the valve(s) can be actuated to occur immediately after detection of the preselected pressure differential threshold (which can also be considered a pre-selected cake breakthrough threshold), or can be actuated to occur after a pre-selected post cake breakthrough drying time period that is to pass after the pre-selected pressure differential condition is detected. The pre-selected post cake breakthrough drying time period can be a suitable value (e.g. between greater than 0 seconds and 20 seconds, between greater than 0 seconds and 60 seconds, between greater than 0 seconds and 120 seconds, etc.) to account for the particular filtration system.

[0060] In some embodiments, the pre-selected post breakthrough drying time period can be greater than 0 seconds and less than 5 seconds or greater than 0 seconds and less than 10 seconds. In other embodiments, the closing of the valves may be configured to occurimmediately after the pre-selected pressure differential condition is detected (e.g. there is no use of the pre-selected post breakthrough drying time period or the pre-selected post breakthrough drying time period is set to be 0 seconds).

[0061] After the cake breakthrough condition is detected and the first valve FV115 and / or the second valve FV114 (when utilized) can be closed, the filtration apparatus 1 can be moved to its open position for discharging of the dried filter cakes 13. As noted above, this may also occur after the pre-selected post breakthrough drying time period has passed when the pre-selected post breakthrough drying time period is utilized.

[0062] Some filtration cycles may include one or more cleaning cycles after the filter cakes 13 are formed. In such situations, the filtration apparatus 1 may not be opened. Instead, at least one cleaning cycle may occur in which a cleaning solution from a source of the cleaning solution can be fed to the cavities for passing through the filter cakes 13 for cleaning the filter cakes (e.g. to remove undesired elements from the particulates of the filter cakes 13). After cleaning, the filter cake may again be dried via the compressed gas in a drying cycle. The drying cycle can again occur similar to the drying cycle using compressed gas discussed above.

[0063] For example, after the cleaning solution has been fed to the cavities of the filtration apparatus having the filter cakes 13 formed thereon, the compressed gas can be fed to the filtration apparatus 1 via at least one compressor, which can compress air and feed the compressed air to the cavities of the closed plates via the compressed gas feed line 9, for example. For example, the first valve FV115 and (when utilized) the second valve FV114 can be opened for feeding the compressed gas into the cavities having the filter cakes 13 while the filtration apparatus 1 is in its closed position.

[0064] The compressed gas can be fed until the pressure of the cavities is at a similar pressure (e.g. the same pressure or within + / - 5% of the same pressure) as the pressure of the source of the compressed gas. Liquid of the cleaning solution can pool on the filter media 7 during this time and block further passage of compressed gas. Once the liquid starts to pass through the filter media 7, the pressure can change greatly as the pressure of the cavities at the inlet at which it receives the compressed gas can be lowered to the pressure at an outlet through which liquid is to drain from the cavity, and the higher pressure compressed gas is able to also pass through the inlet and outlet. Such an operational condition can be considered a “cake breakthrough” or a“breakthrough” condition. We have determined that at this “cake breakthrough” condition, the filter cakes 13 are not completely dry because there is still residual moisture that can be reduced with further compressed gas blow, but the initial “wall” of liquid that can create a pressure differential between the cavity inlet and outlet has been forced out of the filter cake 13.

[0065] Prior to this cake breakthrough condition occurring, almost no compressed gas fed to the cavities of the closed filtration apparatus 1 may be consumed (e.g. only enough compressed gas may be supplied to cavities defined by the immediately adjacent and closed plates 4 for pressurizing the cavities for acting on the filter cakes 13 to remove the “wall” of liquid, which can represent the bulk of remaining filter cake moisture.

[0066] Prior to the cake breakthrough event occurring, the pressure of the compressed gas measured by the first pressure sensor PSI 17 and the second pressure sensor PSI 16 can be about the same. For example, there may only be a slight differential in pressure detected by those sensors prior to the cake breakthrough condition occurring during a filtration cycle while the filtration apparatus 1 is in its closed position. After the breakthrough condition has occurred, the pressure difference between the pressure measured, or detected, by the first pressure sensor and the pressure measured, or detected, by the second pressure sensor can be substantial.

[0067] When the detected pressure differential corresponds to the pre-selected pressure differential threshold, or cake breakthrough threshold, the controller CTRL can communicate with the first valve FV115 and / or second valve FV114 to close those valves so that no more compressed air is fed to the filtration apparatus. The closing of the valve(s) can be actuated to occur immediately after detection of the pre-selected pressure differential threshold or can be actuated to occur after a pre-selected post cake breakthrough drying time period that is to pass after the pre-selected pressure differential condition is detected. The pre-selected post cake breakthrough drying time period can be a suitable value to account for the particular filtration system.

[0068] In some embodiments, the pre-selected post breakthrough drying time period can be greater than 0 seconds and less than 5 seconds or greater than 0 seconds and less than 10 seconds. In other embodiments, the closing of the valves may be configured to occur immediately after the pre-selected pressure differential condition is detected (e.g. there is no useof the pre-selected post breakthrough drying time period or the pre-selected post breakthrough drying time period is set to be 0 seconds).

[0069] After the cake breakthrough condition is detected and the first valve FV115 or the second valve FV114 (when utilized) can be closed, the filtration apparatus 1 can be moved to its open position for discharging of the dried filter cakes 13. As noted above, this may also occur after the pre-selected post breakthrough drying time period has passed when the pre-selected post breakthrough drying time period is utilized. Alternatively, yet another cleaning cycle can be performed and a subsequent drying cycle can again occur in various other cycles of operation until the filter cakes 13 are considered to be sufficiently clean to meet a pre-selected content criteria for being discharged. In a discharge operation of the filtration cycle, after the final cake breakthrough is detected, the filtration apparatus 1 can be moved to its open position to facilitate motion of the filter media 7 for discharging the filter cakes 13 via the discharge chute(s) 15 positioned adjacent the plates 4 of the filtration apparatus 1.

[0070] In some embodiments, the pre-selected pressure differential threshold can be a different value to account for different operational cycles (e.g. initial filtering via slurry can have a different pre-selected pressure differential threshold value as compared to a cleaning using a cleaning solution). Also, some phases of operation (e.g. initial filtering, subsequent cleaning, etc.) within a filtration cycle can utilize a pre-selected post breakthrough drying time period while other phases may not. For example, only after a final cleaning phase may a pre-selected post breakthrough drying time period of greater than 0 seconds be utilized (e.g. since other prior cycles may just result in re-wetting of the filter cakes 13 via a cleaning solution, etc.).

[0071] It should be appreciated that the controller CTRL can be part of a control system 20 that is a type of machine that includes hardware. For example, the controller CTRL can include a processor P that is communicatively connected to non-transitory memory M and at least one transceiver T. The memory M can have at least one application A and / or at least one data store DS stored thereon. The memory M can store instructions that are processed by the processor P for evaluation of the pressure data received from the first and second pressure sensors PSI 17 and PSI 16 for determining the pressure differential and evaluating when the pre-selected pressure differential has been reached. The controller CTRL can also be configured to utilize, or notutilize, the pre-selected post breakthrough drying time period as discussed above via the instructions stored in the memory M that can be executed by the processor P.

[0072] The controller CTRL of the control system can be communicatively connected to an operator device or can be a component of an operator device that can be utilized to oversee operations of the filtration apparatus 1. In some embodiments, the operator device can be a workstation, laptop computer, or other type of computer for example. The controller CTRL can be configured to be communicatively connected to at least one input device and at least one output device to facilitate interaction with a user (e.g. via communications with a touch screen, a pointer device, a keyboard, a display, a speaker, a microphone, etc.).

[0073] The controller CTRL can be communicatively connected to the pressure sensors and valves via wired communicative connections or via a network connection (e.g. a wireless local area network connection, a local area network connection, etc.). The controller CTRL can also be connected to other sensors, detectors, control elements, or operator devices as well. For instance, the controller CTRL can also be communicatively connected to actuators that are connected to the plates 4 for adjusting the positions of the plates 4 to adjust the filtration apparatus 1 between its open and closed positions.

[0074] The control system 20 can also include other process control elements. For example, the control system 20 can include sensors (e.g. flow rate sensors, temperature sensors, other pressure sensors), detectors, valves, or other process control equipment that can be communicatively connected to the controller CTRL. The control system can also include at least one operator device that can be communicatively connected to the controller CTRL in embodiments where the controller CTRL is not incorporated into the operator device (e.g. computer or workstation that may run an automated process control application for controlling operations of the filtration apparatus 1).

[0075] Figure 3 illustrates an exemplary embodiment of a process of filtration for separation of solid particulates from liquid of a slurry. Embodiments of this process can be performed via an embodiment of the filtration apparatus 1.

[0076] For example, in a first step SI, slurry can be fed into cavities defined by plates positioned to define cavities having portions of filtration media within the cavities for forming filter cakes 13 on the filter media 7 in the cavities. Such a process can include opening a slurryfeed valve 5f to fill the cavities defined between immediately adjacent closed plates 4 with slurry and closing the feed valve 5f after the cavities are sufficiently filled. In a second step S2, these filtration modules (e.g. filter media within the cavities having the slurry therein) can be pressurized via compressed gas for dewatering the filter cakes 13. This step can include opening of the first valve FV115 and / or the second valve FV114 to feed compressed gas into the cavities as discussed above, for example.

[0077] Figures 4-10 illustrate exemplary features of the filter cake formation processing that can occur during the first and second steps S1-S2. For example, in the first step, the slurry can be fed into the cavities defined by the plates for forming filter cakes on the filter media 7. Figure 4 illustrates such a condition in which the pressure in the closed filtration modules is less than the pressure of the compressed gas CG that can be fed into the filtration modules. Once the compressed gas CG is fed into the filtration apparatus, via opening of the first valve FV115 and / or the second valve FV114, the pressurized gas can be fed to the apparatus so that the compressed gas can start pushing the liquid of the slurry (as indicated via the vertical arrow VA) in each filtration module through the filter media 7 while the particulates can be retained on the filter media for consolidation thereon for formation of filter cakes on the filter media. After the compressed gas CG is fed to the closed filtration modules, the pressure difference between pressure sensors that are upstream and downstream of a compressed dewatering gas feed valve V (e.g. first valve FV115 or second valve FV114) can be determined based on the sensor data received from the first and second pressure sensors PSI 17 and PSI 16 as discussed above. This pressure differential may be 0 or be relatively close to 0 initially as the liquid is being pushed through the filter media for formation of the filter cakes. As can be appreciated from Figure 5-7, the liquid draining can initially result in a consolidation of the solid particulates for formation of a filter cake on the filter media 7.

[0078] As can be seen from Figures 8-10, after the filter cake is consolidated in a compressed state, the liquid within the filter cake can have different liquid levels LL as the liquid is pressed out of the filter cake via the compressed gas to further dewater the filter cake in the second step S2. For instance, the liquid level LL can initially be within an entirety of the filter cake and the liquid level of liquid within the filter cake consolidated onto the filter media can subsequently bereduced to lower levels as the compressed gas CG pushes the liquid through the filter media 7 while the filter media 7 retains the particulates of the slurry thereon.

[0079] In a third step S3, a pressure differential between pressure sensors that are upstream and downstream of a compressed dewatering gas feed valve (e.g. first valve FV115 or second valve FV114) exceeding a pre-selected threshold can be detected to determine the filter cakes 13 are sufficiently dewatered. This relatively large pressure differential can be detected because the liquid is no longer being pushed through the filter cake, which greatly reduces the restriction of the compressed gas CG through the filtration modules of the closed filtration apparatus 1. This reduction in the restriction of the compressed gas results in the pressure detected by the downstream pressure sensor varying greatly from the pressure detected from the upstream pressure sensor, which can result in the detected large pressure differential.

[0080] For instance, in some embodiments, the controller CTRL can make the determination that a breakthrough condition has occurred based on the sensor data received from the first and second pressure sensors PSI 17 and PSI 16 as discussed above, for example. After the cake breakthrough condition is detected, at least one valve of the compressed gas feed line 9 can be closed (e.g. first valve FV115 and / or second valve FV114 can be closed) as the cake breakthrough condition can be identified for indicating a sufficient dewatering has occurred or that sufficient dewatering has occurred after a pre-selected post cake breakthrough drying time period has passed after the cake breakthrough condition was detected. For instance, the controller CTRL can communicate with the valve(s) to close the valve(s) in response to the detected breakthrough condition or after the pre-selected post cake breakthrough drying time period has passed after the breakthrough condition was detected. In some embodiments, the preselected post cake breakthrough drying time period may only occur on a final dewatering step after any prior cleaning and / or washings steps have occurred for the formation of a filter cake have a desired level of moisture and / or a desired level of purity or composition.

[0081] Figure 11 illustrates an exemplary filtration module in which the filter cake has been drained of liquid and sufficiently dewatered and the compressed gas CG can be further provided to perform a blowdown operation for a pre-selected post cake breakthrough drying time period after the cake breakthrough detection occurred. In this blowdown operation, the compressed gas CG can pass through the filter cake as indicated via vertical arrow VA to help further dry the 1filter cake, which may still be moist though there is no a level of liquid within a portion of the filter cake that is positioned on the filter media 7 (e.g. the moisture can be adsorbed in the particulates, but not be in a layer on the filter media within the filter cake). After a sufficient blowdown has occurred, then at least one valve V of the compressed gas feed line 9 can be closed (e.g. first valve FV115 and / or second valve FV114 can be closed).

[0082] In a fourth step S4, the plates 4 can be opened to discharge formed filter cakes 13 or cleaning of the filter cakes can be performed. In the event cleaning is to be performed, a step S4a can be performed in which a cleaning solution is fed to the cavities defined by plates positioned to define the cavities having filter cakes 13 on the filter media 7 in the cavities to facilitate cleaning of the filter cakes. Thereafter, the second step S2 can be performed again to again feed compress gas can be fed to the cavities for pressurizing the filtration modules for dewatering (e.g. removing the liquid from) the filter cakes that were exposed to the cleaning solution for cleaning. Then, the third step S3 may be performed again to again return to the fourth step S4. In the event further cleaning is needed, step S4a may again be repeated.Alternatively, the plates 4 can be opened and a fifth step S5 can be performed so that the filter cakes 13 are moved to a discharge chute 15 for discharging the filter cakes and further processing of the particulate material of the filter cakes can be performed.

[0083] Embodiments of the process shown in Figure 3 can also include other steps or features. For example, embodiments of the process can also include utilization of a pre-selected post cake breakthrough drying time period. Such a time period may only be used in a final cleaning step of a process in some embodiments. Embodiments can also utilize other steps or features. For example, other process steps can include actuation of actuators of the filtration apparatus 1 for adjusting the positions of the plates from open and closed positions, performance of slurry feed valve position adjustments, or other steps.

[0084] Embodiments of the filtration apparatus 1, control system 20, and process for filtration can facilitate improved filtration operational capacity with higher quality filter cake formation. Some embodiments can provide significantly improved yields of higher quality filter cake having more reliable and uniform moisture content, for example. Also, embodiments can provide improved operational flexibility that can also use less compressed gas and / or power forcompression of the gas, which can improve the environmental impact on operations of the filtration apparatus 1 as well.

[0085] It should be appreciated that modifications to the filtration apparatus 1, control device for a filter press, process of filtration, process of detecting sufficient filter cake dewatering, control system, and methods of making and using the same can be made to meet a particular set of criteria for different embodiments of the filtration apparatus 1 or process. For instance, the size, shape, and thickness of different structural features of a filter device (e.g. piping, filter media 7, plates 4, etc.) can be adapted to accommodate a particular set of design criteria. As another example, the conduit apparatus 20 can be adapted for a particular installation situation.

[0086] As yet another example, embodiments of the filtration apparatus 1 and the filtration process can each be configured to include other process control elements positioned and configured to monitor and control operations (e.g. temperature and pressure sensors, flow sensors, an automated process control system having at least one work station that includes a processor, non-transitory memory and at least one transceiver for communications with the sensor elements, valves, and controllers for providing a user interface for an automated process control system that may be run at the work station and / or another computer device of the plant, etc.). It should be appreciated that embodiments can utilize a distributed control system (DCS) for implementation of one or more processes and / or controlling operations of an apparatus or process as well.

[0087] As another example, it is contemplated that a particular feature described, either individually or as part of an embodiment, can be combined with other individually described features, or parts of other embodiments. The elements and acts of the various embodiments described herein can therefore be combined to provide further embodiments. Thus, while certain exemplary embodiments of a process, an apparatus, a control system, and methods of making and using the same have been shown and described above, it is to be distinctly understood that the invention is not limited thereto but may be otherwise variously embodied and practiced within the scope of the following claims.

Claims

What is claimed is:

1. A filtration apparatus for separation of solid particulates from a slurry comprising liquid and the solid particulates, the filtration apparatus comprising: a plurality of moveable plates that are adjustable from closed positions to open positions; moveable filter media positioned between immediately adjacent plates such that slurry is positionable on the filter media when the plates are in their closed positions to separate the solid particulates from the liquid for forming filter cake on the filter media, the filter media being moveable when the plates are in their open position to discharge the filter cake; a compressed gas feed line in fluid communication with the plates to feed compressed gas into cavities defined when the plates are in their closed positions, the compressed gas feed line having a first valve that is adjustable between an open position and a closed position, the first valve positioned so that when the first valve is in the open position, compressed gas from a source of compressed gas that is connectable to the compressed gas feed line is feedable to the cavities when the plates are in their closed position, and the compressed gas is stopped from being passable into the cavities when the first valve is in the closed position; a first pressure sensor positioned to detect a pressure of the compressed gas feed line at a location that is upstream of the first valve; a second pressure sensor positioned to detect a pressure of the compressed gas feed line at a location that is downstream of the first valve in a downstream portion of the compressed gas feed line that extends from the first valve to the plates for feeding the compressed gas to the cavities; a controller communicatively connected to the first pressure sensor and the second pressure sensor to detect a pressure differential between (a) the pressure of the compressed gas feed line at the location that is upstream of the first valve and (b) the pressure of the compressed gas feed line at the location that is downstream of the first valve to detect a cake breakthrough for closing of the first valve.

2. The filtration apparatus of claim 1, wherein the controller comprises a processor communicatively connected to a non-transitory memory, the controller also being communicatively connected to the first valve.

3. The filtration apparatus of claim 1, wherein the compressed gas feed line has a second valve that is adjustable between an open position and a closed position, the second valve being positioned downstream of the first valve.

4. The filtration apparatus of claim 3, wherein the second valve is positioned between the first valve and the second pressure sensor and the first valve is positioned between the first pressure sensor and the second valve.

5. The filtration apparatus of claim 4, wherein the first valve is a modulating valve and the second valve is a control valve.

6. The filtration apparatus of claim 3, wherein the controller is communicatively connected to the first valve and / or the second valve to actuate adjustment of the first valve and / or the second valve in response to detection of the cake breakthrough.

7. The filtration apparatus of claim 1, wherein the controller is communicatively connected to the first valve to actuate adjustment of the first valve in response to detection of the cake breakthrough.

8. The filtration apparatus of claim 1, wherein the filter media is comprised of filter cloth.

9. The filtration apparatus of claim 1, wherein the filtration apparatus is configured as a vertical filter press.

10. A control system for a filtration apparatus, the control system comprising:a first pressure sensor positioned to detect a pressure of a compressed gas feed line that is positioned at a location that is upstream of a first valve of the compressed gas feed line; a second pressure sensor positioned to detect a pressure of the compressed gas feed line at a location that is downstream of the first valve in a downstream portion of the compressed gas feed line that extends from the first valve to a plurality of plates in their closed positions for feeding the compressed gas into cavities defined by the plates that have moveable filter media positioned therein such that slurry is positionable on the filter media to separate the solid particulates from the liquid for forming filter cake on the filter media; a controller communicatively connected to the first pressure sensor and the second pressure sensor to detect a pressure differential between (a) the pressure of the compressed gas feed line at the location that is upstream of the first valve and (b) the pressure of the compressed gas feed line at the location that is downstream of the first valve to detect a cake breakthrough for closing of the first valve; the controller comprising a processor communicatively connected to a non-transitory computer readable medium.

11. The control system of claim 10, wherein the controller is communicatively connected to the first valve to actuate adjustment of the first valve in response to detection of the cake breakthrough.

12. The control system of claim 10, wherein the compressed gas feed line has a second valve that is adjustable between an open position and a closed position, the second valve being positioned downstream of the first valve, the second valve being positioned between the first valve and the second pressure sensor and the first valve being positioned between the first pressure sensor and the second valve; the controller being communicatively connected to the first valve and the second valve to actuate adjustment of the first valve and the second valve in response to detection of the cake breakthrough.

13. A process for filtration, the process comprising:feeding slurry into cavities defined by immediately adjacent plates of a filtration apparatus in a closed position for filtration of the slurry to form filter cakes; pressurizing the cavities for dewatering of the filter cakes; detecting a pressure differential based on pressure data from a first pressure sensor and pressure data from a second pressure sensor to identify a cake breakthrough via the pressure differential exceeding a pre-selected threshold; opening the plates to discharge the filter cakes after the cake breakthrough is identified.

14. The process of claim 13, wherein: the pressurizing the cavities for dewatering of the filter cakes includes feeding compressed gas into the cavities via a compressed gas feed line; and the first pressure sensor is positioned to detect a pressure of the compressed gas feed line upstream of a first valve of the compressed gas feed line and the second pressure sensor is positioned to detect a pressure of the compressed gas feed line at a location that is downstream of the first valve in a downstream portion of the compressed gas feed line that extends from the first valve for feeding the compressed gas into the cavities.

15. The process of claim 14, wherein each of the cavities has filter media positioned therein for draining of liquid from the slurry so a filter cake is formable on the filter media.

16. The process of claim 14, comprising: in response to detection of the cake breakthrough, closing the first valve.

17. The process of claim 16, wherein the closing of the first valve occurs after a pre-selected post cake breakthrough drying time period has passed after the cake breakthrough was detected.

18. The process of claim 14, wherein the detecting of the pressure differential based on the pressure data from the first pressure sensor and the pressure data from the second pressure sensor to identify the cake breakthrough via the pressure differential exceeding the pre-selectedthreshold is performed by a controller that is communicatively connected to the first pressure sensor and the second pressure sensor.

19. The process of claim 14, comprising: closing the first valve in response to the identification of the cake breakthrough; passing a cleaning fluid to the cavities; pressurizing the cavities for dewatering of the filter cakes after the passing of the cleaning fluid to the cavities; detecting a pressure differential based on the pressure data from the first pressure sensor and the pressure data from the second pressure sensor to identify the cake breakthrough via the pressure differential exceeding a pre-selected threshold after the cleaning fluid is passed to the cavities; and wherein the opening of the plates to discharge the filter cakes after the cake breakthrough is identified is performed after the filter cakes are cleaned via the cleaning fluid and the cake breakthrough is identified after the cleaning fluid is passed to the cavities.

20. The process of claim 14, wherein the compressed gas is compressed air.

Images