Method of enhancing hydration of viscosifiers using controlled mechanically induced cavitation

Abstract

A method of hydrating a dry powdered viscosifier such as a powdered polymer is disclosed. The method includes mixing the powdered viscosifier with a solvent such as water to form a mixture; moving the mixture through a cavitation zone; inducing energetic shock waves and pressure fluctuations in the mixture by mechanically inducing cavitation events within the mixture, the shock waves and pressure fluctuations untangling, separating, and straightening polymer molecule chains and distributing the chains throughout the mixture, and extracting the resulting hydrated viscosifier from the cavitation zone.

What is claimed is: 
     
         1 . A method of enhancing hydration of a powdered viscosifier comprising the steps of:
 (a) introducing a viscosifier containing non-hydrated powdered particles into a flow of a solvent or hydrating fluid to produce a mixture;   (b) feeding the mixture into a controlled cavitation reactor, wherein the mixture flows from sides of a rotor of the controlled cavitation reactor through a cavitation zone defined between an outer peripheral surface of the rotor and a wall of a housing of the controlled cavitation reactor, and into the rotor through a plurality of bores formed in the rotor   (c) as the rotor of the controlled cavitation reactor is rotated, generating cavitation events within the mixture in a low shear environment within the controlled cavitation reactor;   (d) controlling a rotor rotation rate as the mixture flows through the cavitation zone to control the cavitation events for generating shock waves that result in cavitation induced pressure variations that propagate through the mixture as the mixture flows through the cavitation zone to substantially separate and disperse the non-hydrated powdered particles of the viscosifier within the mixture and increase surface area contact between the solvent or hydrating fluid and the non-hydrated powdered particles of the viscosifier;   (e) as a result of step (d), forcing solvent molecules into and out of the powder particles to separate, untangle, hydrate, and straighten viscosifier molecule chains contained within the non-hydrated powdered particles of the viscosifier to thereby form substantially uniform hydrated viscosifier molecule chains without causing covalent bond breakage or polymer chain scission;   (f) distributing the hydrated viscosifier molecule chains substantially homogeneously throughout the mixture; and   (g) collecting a resulting mixture.   
     
     
         2 . The method of  claim 1  where in step (a) the viscosifier comprises a polymer. 
     
     
         3 . The method of  claim 2  wherein the polymer comprises dehydrated polymer chains. 
     
     
         4 . The method of  claim 1  wherein the solvent or hydrating fluid comprises water. 
     
     
         5 . The method of  claim 1 , further comprising controlling one or more of a dwell time within the controlled cavitation reactor, an energy input, a clearance between the rotor and the housing, a temperature of the mixture, a concentration of the mixture, a particulate grind size of the non-hydrated powdered particles of the viscosifier, or a combination thereof, in conjunction with controlling the rotor rotation rate as the mixture moves through the cavitation zone to control the cavitation events generated within the mixture. 
     
     
         6 . The method of  claim 1  wherein generating cavitation events is conducted without heating the mixture or adding a secondary solvent to the mixture. 
     
     
         7 . The method of  claim 1 , wherein generating cavitation events within the mixture comprises forming a low pressure zone within the cavitation zone and forming cavitation bubbles within the bores of the rotor, wherein shock waves and cavitation induced pressure variations that propagate through the mixture are formed upon collapse of the cavitation bubbles. 
     
     
         8 . The method of  claim 1  wherein step (d) further comprises breaking up lumps of powdered viscosifier powder to minimize fish eyes within the mixture. 
     
     
         9 . The method of  claim 1  wherein (a) comprises subjecting the collected resulting viscosifier and solvent or hydrating fluid to a batch mixing process. 
     
     
         10 . The method of  claim 1  further comprising the step of subjecting the collected resulting mixture to a batch mixing process following step (g). 
     
     
         11 . A method of hydrating a viscosifier:
 feeding a flow of a solvent or hydrating fluid through a first port of a controlled cavitation reactor;   introducing the viscosifier comprising non-hydrated powdered particles through a second port of the controlled cavitation reactor and into the flow of the solvent or hydrating fluid, wherein the solvent and non-hydrated powdered particles of the viscosifier are mixed, thereby forming a mixture;   directing the mixture into a cavitation zone of the controlled cavitation reactor defined between a peripheral surface of a rotor and a side wall of a housing of the controlled cavitation reactor;   operating the controlled cavitation reactor including controlling a rotor rotation rate thereof so as to generate, in a low shear environment, cavitation events within the mixture;   wherein generating the cavitation events comprises forming cavitation bubbles within the mixture to create shock waves that result in cavitation induced pressure variations that propagate through the mixture upon collapse of the cavitation bubbles;   wherein the cavitation events force solvent or hydrating fluid molecules into and out of the powder particles sufficient to thereby separate, untangle, hydrate, and straighten viscosifier molecule chains contained within the non-hydrated powdered particles of the viscosifier to form hydrated viscosifier molecule chains without causing covalent bond breakage or polymer chain scission; and   collecting a resulting mixture from the controlled cavitation reactor.   
     
     
         12 . The method of  claim 11  wherein the peripheral surface of the rotor comprises a plurality of radial bores and wherein the cavitation bubbles are generated as the mixture flows through the bores. 
     
     
         13 . The method of  claim 11  wherein the rotation rate of the rotor is controlled in view of a concentration of the non-hydrated powdered particles of the viscosifier within the solvent or hydrating fluid. 
     
     
         14 . The method of  claim 11  wherein operating the controlled cavitation reactor further comprises controlling one or more of a dwell time of exposure of the non-hydrated powdered particles of the viscosifier within the mixture to the shock waves and the cavitation pressure variations, controlling an energy input, a clearance between the peripheral surface of the rotor and the housing defining the cavitation zone, a temperature of the mixture, a concentration of the mixture, a particulate grind size of the non-hydrated powdered particles of the viscosifier, or combination thereof. 
     
     
         15 . The method of  claim 11  wherein operating the controlled cavitation reactor further comprises breaking lumps of the non-hydrated powdered particles of the viscosifier sufficient to minimize fish eyes in the mixture. 
     
     
         16 . The method of  claim 11  wherein operation of the controlled cavitation reactor to form the resulting mixture is a part of a batch hydration process as a side stream. 
     
     
         17 . The method of  claim 11  wherein operation of the controlled cavitation reactor increases hydration yield of the resulting mixture by about 20% to about 30%. 
     
     
         18 . The method of  claim 11  wherein generating the cavitation events is conducted without heating the mixture or adding a secondary solvent or hydrating fluid to the mixture.