Abstract: A method of inhibiting or retarding formation of hydrates from water and a lower alkane, such as methane or ethane, involves adding additives which comprise (i) a corrosion inhibitor and (ii) a salt which is of formula [R1(R2)XR3]+Y−, wherein each of R1, R2 and R3 is bonded directly to X, each of R1 and R2, which may be the same or different is an alkyl group of at least 4 carbons, X is S, NR4 or PR4, wherein each of R3 and R4 which may be the same or different represents hydrogen or an organic group, with the proviso that at least one of R3 and R4 is an organic group of at least 4 carbons, and Y is an anion, the additives being added in an amount effective to inhibit or retard hydrate formation, to a medium susceptible to hydrate formation.

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):[R1(R2)XR3]+Y− 1/v, I wherein each of R1, R2 and R3 is bonded directly to X, each of R1 and R2, which may be the same or different is an alkyl group of at least 4 carbons, X is S, NR4 or PR4, wherein each of R3 and R4 which may be the same or different represents hydrogen or an organic group, with the proviso that at least one of R3 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.

Abstract: A method of inhibiting or retarding formation of hydrates from water and a lower alkane, such as methane or ethane, involves adding additives which comprise (i) a corrosion inhibitor and (ii) a salt which is of formula [R.sup.1 (R.sup.2)XR.sup.3 ].sup.+ Y.sup.-, wherein each of R.sup.1, R.sup.2 and R.sup.3 is bonded directly to X, each of R.sup.1 and R.sup.2, which may be the same or different is an alkyl group of at least 4 carbons, X is S, NR.sup.4 or PR.sup.4, wherein each of R.sup.3 and R.sup.4 which may be the same or different represents hydrogen or an organic group, with the proviso that at least one of R.sup.3 and R.sup.4 is an organic group of at least 4 carbons, and Y is an anion, the additives being added in an amount effective to inhibit or retard hydrate formation, to a medium susceptible to hydrate formation.