Method for continuous monitoring and optimization of recovery process

Abstract

Systems and methods for exacting elements of interest, such as lithium, from an aqueous material are described herein. The systems generally use multiple vessels with selective media in each vessel to accomplish extraction of the element of interest. The vessels are operated in cyclic, permuted fashion to move between absorption and desorption operations by routing flows of streams for accomplishing such operations among the vessels in programmed ways. Sensors configured to detect total dissolved solids, or a parameter related to total dissolved solids, are used to detect endpoints for mode switching and to ascertain other aspects of system performance.

We claim: 
     
         1 . A system for extracting an element of interest from an aqueous material, the system comprising:
 a first vessel containing a first selective medium to extract an element of interest from an aqueous material;   a second vessel containing a second selective medium to extract the element of interest from the aqueous material;   a source of the aqueous material fluidly couplable to the first vessel and the second vessel;   an eluent source fluidly couplable to the first vessel and the second vessel;   a first sensor to measure total dissolved solids (TDS), or a parameter related to TDS, at the first vessel;   a flow system to direct the aqueous material to the first vessel or to the second vessel and to direct the eluent to the first vessel or to the second vessel; and   a controller configured to:
 control the flow system to route one of the aqueous material and eluent to the first vessel; and 
 iteratively vary a flow rate through the first vessel, for each iteration control the first sensor to measure TDS, or the parameter related to TDS, at the first vessel, and determine a target value of the flow rate through the first vessel based on one or more of the measurements. 
   
     
     
         2 . The system of  claim 1 , wherein the flow system is a first flow system, and further comprising a second flow system to route a first effluent of the first vessel and a second effluent of the second vessel. 
     
     
         3 . The system of  claim 2 , wherein the controller is further configured to control the second flow system to route a depleted stream from the first vessel while the aqueous material is routed to the first vessel and to route a product stream from the second vessel while the eluent is routed to the second vessel, and to route a product stream from the first vessel while the eluent is routed to the first vessel and a depleted steam from the second vessel while the aqueous material is routed to the second vessel. 
     
     
         4 . The system of  claim 1 , wherein the flow rate through the first vessel is the flow rate of the aqueous material when the controller controls the flow system to route the aqueous material to the first vessel. 
     
     
         5 . The system of  claim 1 , wherein the flow rate through the first vessel is the flow rate of the eluent when the controller controls the flow system to route the eluent to the first vessel. 
     
     
         6 . The system of  claim 1 , wherein the controller is further configured to adjust the flow rate through the first vessel to the target value of the flow rate through the first vessel. 
     
     
         7 . The system of  claim 1 , further comprising a second sensor to measure TDS, or a parameter related to TDS, at the second vessel, wherein the controller is further configured to iteratively vary a flow rate through the second vessel, for each iteration control the second sensor to measure TDS, or the parameter related to TDS, at the second vessel, and determine a target value of the flow rate through the second vessel. 
     
     
         8 . The system of  claim 7 , wherein the controller is further configured to adjust the flow rate through the first vessel to the target value of the flow rate through the first vessel, and to adjust the flow rate through the second vessel to the target value of the flow rate through the second vessel. 
     
     
         9 . The system of  claim 7 , wherein the first sensor is located at an outlet of the first vessel and the second sensor is located at an outlet of the second vessel. 
     
     
         10 . The system of  claim 9 , further comprising a third sensor to measure TDS, or a parameter related to TDS, the third sensor located at an inlet of the first vessel, and/or a fourth sensor to measure TDS, or a parameter related to TDS, the fourth sensor located at an inlet of the second vessel. 
     
     
         11 . The system of  claim 10 , wherein the controller is further configured to compare the measurements of two or more of the first sensor, the second sensor, the third sensor, and the fourth sensor and to adjust the flow rate through the first vessel, the flow rate through the second vessel, or both based on the comparison. 
     
     
         12 . A method, comprising:
 extracting an element of interest from an aqueous material using at least a first vessel containing a first selective medium and a second vessel containing a second selective medium, wherein extracting the element of interest includes coupling a source of the aqueous material to the first vessel and to the second vessel to load the element of interest onto the first and second selective medium and coupling an eluent source to the first vessel and to the second vessel to unload the element of interest from the first and second selective medium,   wherein the method further includes routing a target fluid to the first vessel, wherein the target fluid is one of the aqueous material and eluent;   iteratively varying a flow rate of the target fluid to the first vessel,   measuring total dissolved solids (TDS), or a parameter related to TDS, at the first vessel for each iteration; and   determining a target value of the flow rate of the target fluid through the first vessel based on the one or more of the measurements.   
     
     
         13 . The method of  claim 12 , wherein the extracting the element of interest is performed using a simulated moving bed process,
 wherein the simulated moving bed process includes cyclically permuting the first and second vessels between a set of stations,
 wherein a first subset of the set of stations is fluidly connected to an aqueous material source and a second subset of the set of stations is fluidly connected to an eluent source, 
 wherein the cyclic permutation is obtained via switching positions of one or more fluid circulation devices, and
 wherein extracting the element of interest includes controlling the position of the one or more fluid circulating devices so that the first vessel is fluidly connected to the aqueous source in a first station of the set of stations, and subsequently controlling the position of the fluid circulating devices so that the first vessel is fluidly connected to the eluent source in a second station of the set of stations. 
 
   
     
     
         14 . The method of  claim 12 , further including:
 routing the target fluid to the second vessel,   iteratively varying a flow rate of the target fluid to the second vessel,   measuring total dissolved solids (TDS), or a parameter related to TDS, at the second vessel for each iteration; and   determining a target value of the flow rate of the target fluid through the second vessel based on the one or more of the measurements.   
     
     
         15 . The method of  claim 13 , comprising:
 routing the target fluid to the second vessel,   iteratively varying a flow rate of the target fluid to the second vessel,   measuring total dissolved solids (TDS), or a parameter related to TDS, at the second vessel for each iteration; and   determining a target value of the flow rate of the target fluid through the second vessel based on the one or more of the measurements,   
       the method further comprising flowing the target fluid through the first vessel at a target value of the flow rate of the target fluid through the first vessel when the first vessel is in the first station and flowing the target fluid through the second vessel at the target value of the flow rate of the target fluid through the second vessel when the second vessel is in the first station. 
     
     
         16 . The method of  claim 12 , wherein the parameter related to TDS comprises a conductivity or a density. 
     
     
         17 . The method of  claim 12 , wherein the TDS, or the parameter related to TDS, is measured at the inlet or the outlet of the first vessel, or both. 
     
     
         18 . The method of  claim 13 , wherein the vessels are cyclically permuted counter-current relative to the flow of the aqueous material and eluent. 
     
     
         19 . The method of  claim 12 , wherein the target fluid is the aqueous material, wherein the method further includes routing the eluent to the first vessel,
 iteratively varying the flow rate of the eluent to the first vessel,   measuring total dissolved solids (TDS), or a parameter related to TDS, at the first vessel for each iteration; and   determining a target value of the flow rate of the eluent through the first vessel based on the one or more of the measurements.   
     
     
         20 . The method of  claim 12 , wherein flowing the target fluid to the first vessel is performed using one or more fluid circulation devices wherein the method includes detecting a leak in the one or more fluid circulation devices based on the one or more measurements.