Exxon Chemical Patents, Inc.

Nguyen Van-Det

Peter M Robinson

Philip D Raby

K T Chang

The dewatering of sludge is improved by utilizing a water-soluble cationic copolymer in the aqueous phase of a water-in-oil emulsion wherein the copolymer has been prepared by (i) preparing an aqueous solution of a non-ionic monomer and a portion of the cationic monomer, (ii) emulsifying the aqueous solution in a hydro-carbon oil to form a water-in-oil emulsion, (iii) adding the balance of the total intended cationic monomer to the emulsion while substantially no polymerization is occurring, and (iv) polymerizing the monomers.

Improved method of dewatering sludge

Copolymer water-in-oil emulsions of 2-acrylamido-2-methylpropane sulphonic acid (AMPS) monomer and an anionic comonomer such as methacrylic acid are prepared with substantially less coagulum formation by means of a specific dual surfactant system. The resultant emulsions have enhanced long-term storage stability.

AMPS copolymer emulsions with improved stability

Water-in-oil emulsions of cationic water-soluble copolymers which are prepared by incorporating only a portion of the cationic monomer in the aqueous phase prior to forming the water-in-oil emulsion in which polymerization will occur, forming the emulsion, adding the balance of the cationic monomer such that essentially no polymerization occurs immediately after the addition, and polymerizing the monomers. Copolymers prepared by this process show improved performance over conventionally prepared cationic copolymers.

Cationic monomer delayed addition process

Water-in-oil emulsions of water-soluble polymers, i.e. polyacrylamides, which are subject to freeze-thaw degradation are stabilized against repeated freeze-thaw cycles by incorporating specific ethoxylated alkylphenol surfactants containing low levels of ethoxylation. Moreover, the resultant emulsions exhibit superior resistance to sheet gel formation under ambient storage conditions.

Freeze-thaw stable polyacrylamide emulsions

A Mannich emulsion containing a stabilizing amount of a guanidine salt has been found to exhibit substantially increased long term stability, even at elevated temperature.

Stabilized Mannich emulsions

An improved cationic water-soluble polymer is prepared from acrylamide, a cationic monomer such as dimethylaminoethyl methacrylate dimethylsulfate quaternary, and a waste stream which is produced as a result of the transesterification reaction between dialkylamino alcohols and acrylates which is used to prepare the cationic monomer. The polymers are especially useful in dewatering applications.

Cationic polymers

Water-in-oil emulsions of water-soluble polymers, i.e. polyacrylamides, which are subject to freeze-thaw degradation are stabilized against repeated freeze-thaw cycles by incorporating specific substituted succinic anhydrides.

Water-in-oil emulsions of monomers which form water-soluble polymers are polymerized in the presence of a biphase initiator system containing both an oil-soluble initiator and a water-soluble initiator or activator or alternatively a water-soluble initiator and an oil-soluble activator which results in polymers having improved performance characteristics. In addition, the system permits the satisfactory polymerization of monomers which could not have been reproducibly polymerized.

Growing community of inventors

Midland, GA, United States of America

Nguyen Van-Det