Continuous dissolution reactor

Abstract

A method for producing a rich solvent containing a dissolved compound at an intended concentration level includes filling one of two storage containers with lean solvent and fluidly connecting said storage container to a dissolution reactor containing the compound to be dissolved. The method further includes the following steps: i) enriching the lean solvent in the storage container being fluidly connected to the dissolution reactor by circulating the lean solvent between the dissolution reactor and said storage container, ii) emptying, if present, rich solvent from one of the two storage containers not fluidly connected to the dissolution reactor to a product handling facility, and then filling said storage container with lean solvent, and iii) when the solvent in step i) has reached the predetermined concentration level of dissolved compound, fluidly disconnecting said storage container in step i) from the dissolution reactor and fluidly connecting the dissolution reactor to the said storage container in step ii) being filled with lean solvent, and then go to step i).

1 . A method for producing a rich solvent containing a dissolved compound at an intended concentration level, wherein the method comprises:
 filling one of two storage containers with lean solvent and fluidly connecting said storage container to a dissolution reactor containing the compound to be dissolved,   wherein the method further comprises the following steps:
 i) enriching the lean solvent in the storage container being fluidly connected to the dissolution reactor by circulating the lean solvent between the dissolution reactor and said storage container, 
 ii) emptying, if present, rich solvent from one of the two storage containers not fluidly connected to the dissolution reactor to a product handling facility, and then filling said storage container with lean solvent, and 
 iii) when the solvent in step i) has reached the predetermined concentration level of dissolved compound, fluidly disconnecting said storage container in step i) from the dissolution reactor and fluidly connecting the dissolution reactor to the said storage container in step ii) being filled with lean solvent, 
 and then go to step i). 
   
     
     
         2 . A method for producing a rich solvent containing a dissolved compound at an intended concentration level,
 wherein the method comprises:   applying three storage containers labelled as no. 1, 2 and 3, respectively, and one dissolution reactor containing the compound to be dissolved,   set index n=1,   filling the storage container labelled no. 1 with a volume of lean solvent and fluidly connecting it to the dissolution reactor,   wherein the method further comprises the following steps:   i) enriching the solvent in the no. 1 labelled storage container by circulating it between the dissolution reactor and said storage container,   ii) if index n=1 go to step iii) or else: emptying the no. 2 labelled storage container's content of a rich solvent to a product handling facility,   iii) filling the no. 3 labelled storage container with a volume of lean solvent, and   iv) when the solvent in step i) has reached the intended concentration level of dissolved compound, fluidly disconnecting the no. 1 labelled storage container from the dissolution reactor and fluidly connecting the no. 3 labelled storage container to the dissolution reactor, and   v) relabel the storage containers such that the no. 1 storage becomes labelled the no. 2 storage container, the no. 2 storage container becomes labelled the no. 3 storage container, and the no. 3 storage container becomes labelled the no. 1 storage container, set index n=n+1, and go to step i).   
     
     
         3 . The method according to  claim 2 , wherein steps i) to iii) are executed simultaneously. 
     
     
         4 . The method according to  claim 2 , wherein the emptying of rich solvent from the no. 2 labelled storage container to the product handling facility is adapted to take equally long time to empty the no. 2 labelled storage container as it takes to enrich the solvent in the no. 1 labelled storage container from lean solvent to rich solvent containing the intended concentration level of dissolved compound. 
     
     
         5 . The method according to  claim 1 , wherein the lean solvent is a mineral acid, preferably a hydrochloric acid (HCl), nitric acid (HNO 3 ), sulphuric acid (H 2 SO 4 ), or a mixture thereof, and most preferably a solution of sulphuric acid, water and hydrogen peroxide (H 2 O 2 ). 
     
     
         6 . The method according to  claim 5 , wherein the compound to be dissolved is a metal. 
     
     
         7 . The method according to  claim 6 , wherein the concentration of sulphuric acid in the lean solvent is adapted such that when the lean solvent is enriched to rich solvent containing the intended concentration level of the dissolved compound, the sulphuric acid concentration of the rich solvent is less than 0.100 molar. 
     
     
         8 . A process plant, comprising:
 a dissolution reactor comprising a first dissolution chamber comprising a lower inlet for a solvent, an upper inlet for solid compound, and an outlet for solvent located below the upper inlet and above the lower inlet,   a first storage container,   a second storage container,   a first liquid conduit fluidly connecting a lower end of the first and the second storage containers to the inlet of the first dissolution chamber, wherein the first liquid conduit comprises a first pump, a first valve regulating the flow of solvent from the first storage container into the first liquid conduit, and a second valve regulating the flow of solvent from the second storage container into the first liquid conduit,   a second liquid conduit fluidly connecting the outlet of the first dissolution chamber to an upper end of the first and the second storage containers, where the second liquid conduit comprises a third valve regulating the flow of solvent from the second liquid conduit into the first storage container and a fourth valve regulating the flow of solvent from the second liquid conduit into the second storage container,   a third liquid conduit fluidly connecting the lower end of the first and the second storage containers to a downstream product handling facility, where the third liquid conduit comprises a fifth valve regulating the flow of solvent from the first storage container to the downstream product handling facility, and a sixth valve ( 32 ) regulating the flow of solvent from the second storage container to the downstream product handling facility, and   a fourth liquid conduit ( 40 ) fluidly connecting the upper end of the first and the second storage containers to an upstream supply of lean solvent, where the fourth liquid conduit comprises a seventh valve regulating the flow of solvent from the upstream supply of lean solvent to the first storage container, and an eight valve regulating the flow of solvent from the upstream supply of lean solvent to the second storage container.   
     
     
         9 . The process plant according to  claim 8 , further comprising a third storage container, and wherein:
 the first liquid conduit ( 10 ) further fluidly connects a lower end of the third storage container to the inlet of the first dissolution chamber and comprises a ninth valve regulating the flow of solvent from the third storage container into the first liquid conduit,   the second liquid conduit ( 20 ) further fluidly connects the outlet of the first dissolution chamber to an upper end of the third storage container and comprises a tenth valve regulating the flow of solvent from the second liquid conduit into the third storage container,   the third liquid conduit ( 30 ) further fluidly connects the lower end of the third storage container to the downstream product handling facility, where the third liquid conduit comprises an eleventh valve regulating the flow of solvent from the third storage container to the downstream product handling facility, and   the fourth liquid conduit further fluidly connects the upper end of the third storage container to the upstream supply of lean solvent, where the fourth liquid conduit comprises a twelfth valve regulating the flow of solvent from the upstream supply of lean solvent to the third storage container.   
     
     
         10 . The process plant according to  claim 8 , wherein the dissolution reactor further comprises:
 a second dissolution chamber comprising a lower inlet for a solvent, an upper inlet for solid compound, and an outlet, for solvent located below the inlet and above the inlet,   
       wherein
 the inlet of the first dissolution chamber is fluidly connected to the first liquid conduit, 
 the outlet of the first dissolution chamber is fluidly connected to the inlet of the second dissolution chamber, and 
 the outlet of the second dissolution chamber is fluidly connected to the second liquid conduit. 
 
     
     
         11 . The process plant according to  claim 8 , wherein the dissolution reactor further comprises:
 a second dissolution chamber comprising a lower inlet for a solvent, an upper inlet for solid compound, and an outlet, for solvent located below the inlet and above the inlet, and   a third dissolution chamber comprising a lower inlet, for a solvent, an upper inlet for solid compound, and an outlet, for solvent located below the inlet and above the inlet,   
       and wherein
 the inlet of the first dissolution chamber is fluidly connected to the first liquid conduit, 
 the outlet of the first dissolution chamber is fluidly connected to the inlet of the second dissolution chamber, 
 the outlet of the second dissolution chamber is fluidly connected to the inlet of the third dissolution chamber, and 
 the outlet of the third dissolution chamber is fluidly connected to the second liquid conduit. 
 
     
     
         12 . The process plant according to  claim 8 , wherein the dissolution reactor further comprises:
 a second dissolution chamber comprising a lower inlet for a solvent, an upper inlet for solid compound, and an outlet, for solvent located below the inlet and above the inlet,   
       wherein
 the inlet of the first dissolution chamber is fluidly connected to the first liquid conduit and the outlet of the first dissolution chamber is fluidly connected to the second liquid conduit, 
 the inlet of the second dissolution chamber is fluidly connected to the first liquid conduit and the outlet of the second dissolution chamber is fluidly connected to the second liquid conduit, 
 
       and wherein
 the first liquid conduit further comprises a thirteenth valve regulating the flow of solvent from the first liquid conduit into the first dissolution chamber, and a fourteenth valve regulating the flow of solvent from the first liquid conduit into the second dissolution chamber. 
 
     
     
         13 . The process plant according to  claim 8 , wherein the dissolution reactor further comprises:
 a second dissolution chamber comprising a lower inlet for a solvent, an upper inlet for solid compound, and an outlet, for solvent located below the inlet and above the inlet, and   a third dissolution chamber comprising a lower inlet, for a solvent, an upper inlet for solid compound, and an outlet, for solvent located below the inlet and above the inlet,   
       wherein
 the inlet of the first dissolution chamber is fluidly connected to the first liquid conduit and the outlet of the first dissolution chamber is fluidly connected to the second liquid conduit, 
 the inlet of the second dissolution chamber is fluidly connected to the first liquid conduit and the outlet of the second dissolution chamber is fluidly connected to the second liquid conduit, 
 the inlet of the third dissolution chamber is fluidly connected to the first liquid conduit and the outlet of the third dissolution chamber is fluidly connected to the second liquid conduit, 
 
       and wherein
 the first liquid conduit further comprises a thirteenth valve regulating the flow of solvent from the first liquid conduit into the first dissolution chamber, and a fourteenth valve regulating the flow of solvent from the first liquid conduit into the second dissolution chamber, and a fifteenth valve regulating the flow of solvent from the first liquid conduit into the third dissolution chamber. 
 
     
     
         14 . The process plant according to  claim 8 , further comprising a second solvent pump located in the second liquid conduit. 
     
     
         15 . The process plant according to  claim 8 , further comprising a heat exchanger located in one of the first, second, third or the fourth liquid conduit. 
     
     
         16 . The process plant according to  claim 8 , further comprising an inlet located either in the first, second, or the fourth liquid conduit, or in the first, second, or the third storage container, or in the first, second or the third dissolution chamber for adding additives to the solvent. 
     
     
         17 . The process plant according to  claim 8 , further comprising a solvent strength monitoring unit located in either the first or in the second liquid conduit. 
     
     
         18 . The process plant according to  claim 8 , wherein
 the first, second, third, fourth, fifth, sixth, seventh and the eighth, and if present, the ninth, tenth, eleventh, twelfth, thirteenth, the fourteenth, and the fifteenth valves are actuator controlled valves, and the first, and if present, the second solvent pumps are actuator controlled pumps, and   wherein the process plant further comprises a logic controller unit comprising a processor loaded with a logic commands which when executed regulates the actuators of the first, second, third, fourth, fifth, sixth, seventh and the eighth, and if present, the ninth, tenth, eleventh ( 33 ), twelfth, thirteenth, the fourteenth valves, and the fifteenth valves, and the first, and if present, the second solvent pumps so as to execute a method for producing a rich solvent containing a dissolved compound at a intended concentration level, wherein the method comprises:   filling one of two storage containers with lean solvent and fluidly connecting said storage container to a dissolution reactor containing the compound to be dissolved,   wherein the method further comprises the following steps:
 i) enriching the lean solvent in the storage container being fluidly connected to the dissolution reactor by circulating the lean solvent between the dissolution reactor and said storage container, 
 ii) emptying, if present, rich solvent from one of the two storage containers not fluidly connected to the dissolution reactor to a product handling facility, and then filling said storage container with lean solvent, and 
 iii) when the solvent in step i) has reached the predetermined concentration level of dissolved compound, fluidly disconnecting said storage container in step i) from the dissolution reactor and fluidly connecting the dissolution reactor to the said storage container in step ii) being filled with lean solvent, 
 and then go to step i). 
   
     
     
         19 . A dissolution reactor,
 wherein the dissolution reactor comprises:   a container having a wall and a bottom plate but being open in its upper end,   a corrosion resilient lining covering an inner surface of the wall and bottom plate of the container,   a corrosion resilient basket being open at its bottom end and at its top end, and being located inside the container such that it rests on the inner surface of the bottom plate and extends a first distance upwards inside the container, wherein the basket comprises a perforated plate covering its horizontal cross-sectional area and which is located a second distance above its lover end, and where the second distance<the first distance,   a fluid inlet adapted to inject a liquid into the container from below and into a space confined between the bottom plate, a lower part of the basket, and the perforated plate,   a fluid outlet adapted to extract liquid from the container through the wall at a height being at least the same height at which the upper end of the basket extends inside the container,   a funnel adapted to be suspended from the upper end of the container and being tapered and pointing towards the bottom plate, and which extends a third distance downwards into the container such that the narrow lower end of the funnel is below the upper end of the basket, and   a lid adapted to cover the upper end of the container and wherein the lid is adapted to be fluidly connected to a gas evacuation for extracting eventual gases being formed inside the dissolution reactor.   
     
     
         20 . The dissolution reactor according to  claim 19 , wherein the container is made of a metal, preferably a stainless steel alloy, and where the inner wall of the container is lined with a corrosion resistant lining chosen from one of; a rubber, a polyethylene, a polytetrafluoroethylene, or a vinyl ester. 
     
     
         21 . The dissolution reactor according to  claim 19 , wherein the corrosion resistant basket and the perforated bottom plate is made of a polyethylene, a polyvinyl, a vinyl ester, or a polypropylene. 
     
     
         22 . The dissolution reactor according to  claim 19 , wherein the lid and/or the upper part of the container may comprise one or more openings allowing false air to enter inside the lid. 
     
     
         23 . The process plant according to  claim 8 , wherein the dissolution reactor is a dissolution reactor according to comprises:
 a container having a wall and a bottom plate but being open in its upper end,   a corrosion resilient lining covering an inner surface of the wall and bottom plate of the container,   a corrosion resilient basket being open at its bottom end and at its top end, and being located inside the container such that it rests on the inner surface of the bottom plate and extends a first distance upwards inside the container, wherein the basket comprises a perforated plate covering its horizontal cross-sectional area and which is located a second distance above its lover end, and where the second distance<the first distance,   a fluid inlet adapted to inject a liquid into the container from below and into a space confined between the bottom plate, a lower part of the basket, and the perforated plate,   a fluid outlet adapted to extract liquid from the container through the wall at a height being at least the same height at which the upper end of the basket extends inside the container,   a funnel adapted to be suspended from the upper end of the container and being tapered and pointing towards the bottom plate, and which extends a third distance downwards into the container such that the narrow lower end of the funnel is below the upper end of the basket, and   a lid adapted to cover the upper end of the container and wherein the lid is adapted to be fluidly connected to a gas evacuation for extracting eventual gases being formed inside the dissolution reactor.