Treatment of Aqueous Systems

Abstract

A method is described for selecting a treatment additive for aqueous systems, in which crystal habit modification properties are prioritized; for aqueously preparing a substantially poly-maleic additive through in-situ formation of maleic acid copolymer so that mono-carboxylic acids, non-ionic functional groups, and terminal hydroxyl groups are also formed during polymerization; and for applying such additives for treatment of aqueous systems. Treatment agents resulting from these processes are also described.

The claimed invention is: 
     
         1 . A method of preparing in-situ a substantially maleic acid copolymer, comprising:
 polymerizing at least a portion of a plurality of maleic acid monomer components, wherein some of such maleic acid monomer components are transformed into monomeric repeating units within each of a plurality of polymer molecules,   increasing decarboxylation during said polymerizing,   forming in-situ a copolymer molecule comprising at least one decarboxylated portion of said copolymer molecule,   increasing an average frequency of non-carboxylated monomeric repeating units in said polymer molecules to at least approximately 5 molar %.   
     
     
         2 . A method according to  claim 1 , wherein said polymerizing comprises aqueously polymerizing. 
     
     
         3 . A method according to  claim 2 , wherein said increasing decarboxylation comprises adjusting one or more reaction parameters selected from the group of temperature, metal catalyst concentration, hydrogen peroxide concentration, and other reaction additives. 
     
     
         4 . A method according to  claim 2 , wherein said copolymer molecule further comprises at least one terminal hydroxyl group. 
     
     
         5 . A method according to  claim 3 , wherein said polymerizing further comprises co-polymerizing one or more co-monomers capable of reacting in a free-radical aqueous polymerizing system. 
     
     
         6 . A substantially polymaleic acid copolymer comprising:
 mono-carboxylic acids,   terminal hydroxyl groups,   non-ionic functional groups which aid in adsorption onto a crystal surface,   wherein said non-ionic functional groups and said terminal hydroxyl groups are substantially formed during an aqueous polymerization process, so that said copolymer comprises at least approximately 50 molar % maleic acid and up to 50 molar % of free radical polymerized co-monomers, including at least 5 molar % decarboxylated maleic acid repeating units.   
     
     
         7 . A method comprising:
 applying the copolymer of  claim 6  to treat an aqueous system by modifying a crystal habit of at least one inorganic compound selected from the group consisting of calcium carbonate, calcium sulfate, barium sulfate, strontium sulfate, calcium fluoride, calcium oxalate, calcium phosphate, iron oxides, iron hydroxides, silica, and silicates.   
     
     
         8 . A method according to  claim 7 , wherein the aqueous system is selected from the group consisting of industrial water systems, boilers, cooling towers, evaporators, digestors, membranes, thermal desalination systems, recreational water systems, swimming pools, spas, hot tubs, decorative fountains, potable water systems, reverse osmosis membranes, filtration systems, top-side oil systems, down-hole oil systems, top-side gas systems, down-hole gas systems, squeeze treatments, flood treatments, drilling systems, fracturing applications, mining systems, pulp-and-paper systems, sugar evaporators, ethanol evaporators, household cleaning systems, laundry systems, and textile processing systems. 
     
     
         15 . A method comprising:
 selecting a polymer additive for mineral scale treatment of aqueous systems on a primary basis of crystal habit modification properties, and secondarily based on one or more properties selected from the group of threshold inhibition, sequestration, chelation, stabilization, and particulate dispersion.   
     
     
         16 . A method according to  claim 15 , wherein said polymer additive comprises pluralities of mono-carboxylic acids, non-ionic functional groups, and terminal hydroxyl groups; 
     
     
         17 . A method according to  claim 15 , wherein composition components of said polymer additive comprise ratios of carboxylates and non-ionic compounds, and wherein the ratio of said non-ionic compounds is selected to optimize polymer adsorption on crystal surfaces, and wherein the ratio of carboxylates is selected to retain adequate threshold inhibition, chelation, and sequestration properties of said polymer additive.