| abstract |
A hydrate inhibitor comprising a blend of an additive (i) and at least one of an additive (ii) and an additive (iii) wherein additive (i) is a polymer of an ethylenically unsaturated N-heterocyclic carbonyl compound, with 6-8 ring atoms in the heterocyclic ring, additive (ii) is a corrosion inhibitor and additive (iii) is a salt of formula (I): [R?1(R2)XR3]+Y-¿ 1/v, I wherein each of R?1, R2 and R3¿ is bonded directly to X, each of R?1 and R2¿, which may be the same or different is an alkyl group of at least 4 carbons, X is S, NR?4 or PR4¿, wherein each of R?3 and R4¿ which may be the same or different represents hydrogen or an organic group, with the proviso that at least one of R?3 and R4¿ is an organic group of at least 4 carbons, especially at least 5 carbons, and Y is an anion of valency v, wherein v is an integer of 1-4. |