# US 2019/0169050 A1 · Method of Filtering Water > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0169050 A1 - Document ID: US20190169050A1 - Status: Published application - Kind: A1 - Application number: 16/319,328 - Filed: 2017-07-11 - Published: 2019-06-06 - Earliest claimed: 2016-07-21 - Assignees: BP Exploration Operating Company Limited - Applicants: BP Exploration Operating Company Limited - Inventors: John Henry Crouch; James Lomax; John Dale Williams - Web page: https://patentgrep.com/patent/US20190169050A1 ## CPC - C02F 1/444: {by ultrafiltration or microfiltration} - B01D 61/14: Ultrafiltration; Microfiltration - B01D 61/18: Apparatus therefor - B01D 61/22: Controlling or regulating - B01D 63/031: {Two or more types of hollow fibres within one bundle or within one potting or tube-sheet} - B01D 65/02: Membrane cleaning or sterilisation {; Membrane regeneration} - B01D 2313/54: Modularity of membrane module elements - B01D 2315/08: Fully permeating type; Dead-end filtration - B01D 2315/20: Operation control schemes defined by a periodically repeated sequence comprising filtration cycles combined with cleaning or gas supply, e.g. aeration - B01D 2317/04: Elements in parallel - B01D 2319/04: Elements in parallel - B01D 2321/04: Backflushing - C02F 2303/16: Regeneration of sorbents, filters - C02F: TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE (separation in general B01D; special arrangements on waterborne vessels of installations for treating water, waste water or sewage, e.g. for producing fresh water, B63J; adding materials to water to prevent corrosion C23F; treating radioactively-contaminated liquids G21F9/04; regeneration of reactants for recirculation into processes, see the relevant places for the processes) - B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28) ## Abstract A method of operating a filtration unit of a filtration system includes feeding, during filtration, feed water containing suspended particulate material to an inside of each of a plurality of hollow fibres through a first inlet and a second inlet of each hollow fibre while simultaneously removing a filtrate from an outside of each of the hollow fibres through an outlet of a filtration elements. In addition, the method includes feeding, during back-washing, back-wash water to the outside of the hollow fibres through the outlet of the filtration element. Further the method includes discharging, in a first back-wash cycle, back-wash water containing entrained particulate material from the inside of the hollow fibres from one end thereof. Still further, the method includes discharging, in a second back-wash cycle, back-wash water containing entrained particulate material from the inside of the hollow fibres from the other end thereof. ## Claims ### Claim 1 A method of operating a filtration system, the method comprising: feeding, during filtration, feed water containing suspended particulate material to an inside of each of a plurality of hollow fibres through a first inlet of each of the hollow fibres and a second inlet of each of the hollow fibres while simultaneously removing filtrate from an outside of the hollow fibres through an outlet of at least one filtration element, wherein a filtration system comprises at least one filtration unit including a filtration vessel containing the at least one nitration element wherein the at least one filtration element comprises a plurality of the hollow fibres, wherein each hollow fibre has a first inlet at a first end thereof and a second inlet at a second end thereof, wherein the first inlet and the first outlet of each hollow fibre is in fluid communication with the inside of the hollow fibre, and wherein the outlet of the at least one filtration element is in fluid communication with the outside of the hollow fibres; and feeding, during back-washing, back-wash water to the outside of the hollow fibres through the outlet of the at least one filtration element; discharging, in a first back-wash cycle, back-wash water containing entrained particulate material from the inside of the hollow fibres through the first inlets thereof; and, discharging, in a second back-wash cycle, back-wash water containing entrained particulate material from the inside of the hollow fibres through the second inlets thereof, wherein the first and second back-wash cycles may be performed sequentially in either order. ### Claim 2 (depends on 1) The method of claim 1, wherein the at least one filtration element has a first outlet and a second outlet arranged at a first end and a second end, respectively, thereof; and, during filtration, removing filtrate from the outside of the hollow fibres simultaneously through both the first and second outlets of the at least one filtration element. ### Claim 3 (depends on 1) The method of claim 1, wherein the filtration vessel of the at least one filtration unit contains a plurality of filtration elements each having a first and a second back-wash cycle, and performing the back-wash cycles for the plurality of filtration elements sequentially in any order. ### Claim 4 (depends on 3) The method of claim 3, wherein the filtration vessel of the at least one filtration unit contains a first filtration element having a first and a second back-wash cycle (Cycles A and B) and a second filtration element having a first and a second back-wash cycle (Cycles C and D) and: (i) in Cycle A, feeding the back-wash water to the outlet of the first filtration element and removing back-wash water containing entrained particulates from the first inlets of the first filtration element; (ii) in Cycle B, feeding the back-wash water to the outlet of the first filtration element and removing back-wash water containing entrained particulates from the second inlets of the first filtration element; (iii) in Cycle C, feeding the back-wash water to the outlet of the second filtration element and removing back-wash water containing entrained particulates from the first inlets of the second filtration element; and, (iv) in Cycle D, feeding the back-wash water to the outlet of the second filtration unit and removing back-wash water containing entrained particulate from the second inlets of the second filtration element; and, wherein performing Cycles A to D is effected sequentially in any order. ### Claim 5 (depends on 1) The method of claim 1, wherein the filtration vessel contains a plurality of filtration elements each having a first back-wash cycle and a second back-wash cycle, and performing the first back-wash cycles for each of the filtration elements simultaneously and performing the second back-wash cycles for each of the filtration elements simultaneously, in either order. ### Claim 6 (depends on 1) The method of claim 1, wherein the filtration vessel contains from four to twelve filtration elements each having a first and a second back-wash cycle, and backwashing the filtration elements in two or more subsets each subset comprising at least two filtration elements and backwashing the two or more subsets are successively in any order by performing the first back-wash cycles for each subset of filtration elements simultaneously and performing the second back-wash cycles for each subset of filtration elements simultaneously in either order. ### Claim 7 (depends on 1) The method of claim 1, wherein the filtration system comprises a plurality of filtration units and the filtration vessels of the plurality of filtration units each contain a plurality of filtration elements located at first, second and optional successive positions in the filtration vessels, each filtration element having first and second back-wash cycles, and wherein some or all of the filtration units are back-washed by performing: the first back-wash cycles for the filtration elements located at the first positions of the filtration vessels simultaneously; the second back-wash cycles for the filtration elements located at the first positions of the filtration vessels simultaneously; the first back-wash cycles for the filtration elements located at the second positions of the filtration vessels simultaneously; the second back-wash cycles for the filtration elements located at the second positions of the filtration vessels simultaneously; the first back-wash cycles for the filtration elements located at the or each optional successive positions of the filtration vessels simultaneously; and the second back-wash cycles for the filtration elements located at the or each optional successive positions of the filtration vessels simultaneously; wherein the simultaneous back-wash cycles for the elements located at the first, second and optional successive positions in the filtration vessels are performed sequentially in any order. ### Claim 8 (depends on 7) The method of claim 7, further comprising back-washing of the filtration element of each filtration unit every 50 to 60 minutes. ### Claim 9 (depends on 7) The method of claim 7, wherein, during filtration, providing the feed water for the plurality of filtration unit at a pressure in the range of 2 to 10 bar gauge, preferably, 2.5 to 5.5 bar gauge and at a flow rate of feed water to the first and second inlets of the hollow fibres of each of the plurality of filtration elements in the range of 1.4 to 2.5 m3/hour. ### Claim 10 (depends on 9) The method of claim 9, further comprising, during back-washing, providing the back-wash water for the at least one filtration unit at a pressure in the range of 1.5 to 3.0 bar gauge and a flow rate of the back-wash water to the at least one filtration element during either the first back-wash cycle or the second back-wash cycle in the range of 40 to 50 m3/hour. ### Claim 11 (depends on 7) The method of claim 7, wherein the plurality of the filtration units are arranged in a rack comprising two or more banks of filtration units and the banks of filtration units are back-washed sequentially in any order. ### Claim 12 (depends on 1) The method of claim 1, further comprising periodically adding at least one cleaning chemical to the back-wash water, wherein the cleaning chemical is selected from: (1) acids such as organic acids (in particular citric acid) or protic acids (in particular, hydrochloric acid) for removing inorganic mineral scales from the filtration system; (2) bases such as sodium hydroxide or potassium hydroxide that target organic species that foul the membrane; (3) oxidants or disinfectants such as sodium hypochlorite, chlorine gas or hydrogen peroxide for removing organic materials or biofilms from the membranes; and, (4) surfactants to remove organic materials and inert particles from the membranes. ### Claim 13 A filtration unit comprising: a filtration vessel containing at least one dead-end filtration element, wherein the at least one-filtration element comprises a plurality of hollow fibre microfiltration or ultrafiltration membranes wherein each hollow fibre has a first inlet and a second inlet at the first and second ends thereof, respectively, in fluid communication with the inside of the hollow fibre, and wherein the at least one filtration element has an outlet at one or both of the first and second ends thereof in fluid communication with the outside of the hollow fibres; wherein: (i) the first inlets of the hollow fibres of the at least one filtration element are connected either directly or indirectly to a first dedicated feed line via a first dedicated feed port in the filtration vessel and the second inlets of the hollow fibres of the at least one filtration element are connected either directly or indirectly to a second dedicated feed line via a second dedicated feed port in the filtration vessel; (ii) the outlet of the at least one filtration element is connected either directly or indirectly to a filtrate line via a filtrate port in the filtration vessel; wherein the first and second dedicated feed lines and the filtrate line each have a valve provided with an actuator wherein the actuators are independently actuatable to move the valves between an open and closed position. ### Claim 14 (depends on 13) The filtration unit of claim 13, wherein the at least one filtration element has a first and a second outlet arranged at the first and second ends respectively of the at least one filtration element and the first and second outlets are connected either directly or indirectly to a first filtrate line and second filtrate line respectively via first and second filtrate ports respectively in the filtration vessel and the first and second filtrate lines have valves provided with actuators that are independently actuatable to move the valves between an open and closed position. ### Claim 15 (depends on 13) The filtration unit of claim 13, wherein the filtration vessel is a cylindrical vessel containing at least two filtration elements and wherein first and second feed ports are arranged in the filtration vessel at or near the first and second ends thereof, first and second filtrate ports are arranged in the filtration vessel at or near the first and second ends thereof and one or more side feed ports are arranged in the filtration vessel with a single filtration element arranged on either side of the each of the one or more side feed ports and wherein each of the one or more side feed ports is connected either directly or indirectly to a dedicated side feed line having a valve provided with an actuator that is independently actuatable to move the valve between an open and closed position. ### Claim 16 (depends on 15) The filtration unit of claim 15, wherein the at least two filtration elements are arranged in a row within the cylindrical filtration vessel and wherein each filtration element comprises an outer cylindrical sleeve, an inner perforated pipe and a plurality of hollow fibres arranged in parallel within the annular space formed between the outer cylindrical sleeve and the inner perforated pipe; and, wherein the perforated pipes of adjacent filtration elements are connected together via tubular pipe members and the terminal end of the perforated pipe of a first filtration element in the row is connected via a tubular pipe member to a first filtrate line via a first filtrate port arranged at or near the first end of the filtration vessel and the terminal end of the perforated pipe of the final filtration element of the row is connected via a tubular pipe member to a second filtrate line via a second filtrate port arranged at or near the second end of the filtration vessel. ### Claim 17 (depends on 16) The filtration unit of claim 16, wherein the filtration vessel contains a first and second filtration element arranged in the row. ### Claim 18 (depends on 13) A filtration system comprising a controller and at least one filtration unit of claim 13, wherein: (a) during filtration, the controller instructs the actuators to move the valves on the first dedicated feed line, the second dedicated feed line and the filtrate line to an open position; and, (b) during back-washing, the at least one filtration element is back-washed in two cycles by the controller instructing the actuators to open and close the valves on the flow lines in sequence such the valve on the filtrate line is in an open position and, in a first back-wash cycle, the valve on the first dedicated feed line is in an open position and the valve on the second dedicated feed line is in a closed position, and, in a second back-wash cycle, the valve on the first dedicated feed line is in a closed position and the valve on the second dedicated feed line is in an open position. ### Claim 19 (depends on 17) A filtration system comprising a controller and at least one filtration unit of claim 17, wherein: (a) during filtration, the controller instructs the actuators to move the valves on the first dedicated feed line, the second dedicated feed line, the side feed line, first filtrate line and second filtrate line to open positions; and (b) during back-washing, the first filtration element of the filtration vessel is back-washed in a first and second back-wash cycle (Cycles A and B) and the second filtration element of the filtration vessel is back-washed in a first and second back-wash cycle (Cycles C and D) by the controller instructing the actuators to open and close the valves on the flow lines in sequence wherein: (i) in Cycle A, the valves on the first filtrate line and first feed line are in an open position and the remaining valves in a closed position; (ii) in Cycle B, the valves on the first filtrate line and the side feed line are in an open position and the remaining valves are in a closed position; (iii) in Cycle C, the valves in the second filtrate line and the side feed line are in an open position and the remaining valves are in a closed position; and (iv) in Cycle D, the valves on the second filtrate line and second feed line are in an open position and the remaining valves are in a closed position; and, wherein the Cycles A to D may be performed sequentially in any order. ### Claim 20 (depends on 19) The filtration system of claim 19, further comprising a plurality of filtration units arranged in a rack; a set of vertical headers comprising a first vertical feed header, a second vertical feed header, an additional (side) vertical feed header, a first vertical filtrate header, a second vertical filtrate header; and, a filtrate tank, wherein the filtration units are arranged horizontally in the rack in a plurality of rows arranged one above another, and wherein the first and second vertical feed headers are in fluid communication with the first and second dedicated feed lines of each of the plurality of filtration units, the additional (side) vertical feed header is in fluid communication with the side feed line of each of the plurality of filtration units, and the first and second vertical filtrate headers are in fluid communication with the first and second filtrate lines of each of the plurality of filtration units and wherein the first and second vertical filtrate headers are also in fluid communication with the filtrate tank which is located above the rack. ### Claim 21 (depends on 20) The filtration system of claim 20, wherein the rack comprises one or more sets of vertical headers with a single bank of filtration units arranged on either side of the or each set of vertical headers and wherein each of the banks of filtration units are independently isolatable. ### Claim 22 (depends on 13) The filtration unit of claim 13, wherein the filtration vessel contains a single dead-end filtration element and a single filtrate line to which the outlet of the single dead-end filtration element is directly or indirectly connected. ### Claim 23 A filtration unit comprising: a filtration vessel comprising at least two dead-end filtration elements arranged in a row, wherein each of the at least two dead-end filtration elements comprises a plurality of hollow fibre microfiltration or ultrafiltration membranes, wherein each hollow fibre comprises a first inlet and a second inlet at first and second ends thereof, respectively, in fluid communication with the inside of the hollow fibre, wherein each of the at least two dead-end filtration elements has an outlet at one or both of the first and second ends thereof in fluid communication with the outside of the hollow fibres, wherein each of the at least two filtration elements comprises an inner perforated pipe fluidly connected with the outside of the hollow fibres of that filtration element and wherein the inner perforated pipes of adjacent filtration elements are connected together via tubular pipe members; a first dedicated feed line fluidly connected with the filtration vessel at or near a first end thereof, a second dedicated feed line fluidly connected with the filtration vessel at or near a second end thereof, and one or more dedicated side feed lines, wherein each of the one or more side feed lines is fluidly connected with the filtration vessel via a feed port with a filtration element arranged on either side of each of the one or more side feed ports, a first filtrate line arranged at or near the first end of the filtration vessel and fluidly connected via a tubular pipe member with a terminal end of a perforated pipe of a first filtration element in the row, and a second filtrate line arranged at or near the second end of the filtration vessel and fluidly connected via a tubular pipe member to a terminal end of a perforated pipe of a final filtration element in the row; wherein the first and second dedicated feed lines, the one or more dedicated side feed lines, and the first and second filtrate lines each comprise a valve provided with an actuator whereby the actuators are independently actuatable to move the valves between an open and closed position such that, during back-washing of each of the at least two dead-end filtration elements, back-wash water can be fed to the outside of the hollow fibres through the outlet thereof and, in a first back-wash cycle, back-wash water containing entrained particulate material can be discharged from the inside of the hollow fibres through the first inlets thereof; and, in a second back-wash cycle, back-wash water containing entrained particulate material can be discharged from the inside of the hollow fibres through the second inlets thereof.