Processes and compositions for scavenging hydrogen sulfide
Processes and compositions for scavenging hydrogen sulfide from hydrocarbon streams are disclosed that reduce, if not substantially eliminate, the formation of crystalline or amorphous solids even under cold conditions. The compositions used in the processes comprise a hexahydrotriazine component and an amphiphilic component that form a hydrophobic micelle when the hexahydrotriazine component becomes spent.
1. A process for reducing an amount of sulfhydryl moieties in hydrocarbon streams comprising contacting in the presence of water and at least one amphiphilic moiety said hydrocarbon streams with at least one substituted hexahydrotriazine that is substantially devoid of hydroxyl groups but is soluble in water, for a time sufficient to provide a spent triazine in which at least one hetero nitrogen atom is replaced with a sulfur atom and wherein the amphiphilic moiety is provided in an amount sufficient to form a hydrophobic micelle with said spent triazine, with the proviso that the hexahydrotriazine and amphiphilic moiety are different.
2. The process of claim 1 wherein the substituted hexahydrotriazines is represented by the formula
1,3,5 (tris-R)hexahydrotriazine
wherein each R is the same or different and may be alkyl including branched alkyl of 1 to 20 carbon atoms; aryl of 5 to 10 carbon atoms; alkoxyalkylene of 2 to 20 carbon atoms; and alkyleneamines of 1 to 20 carbon atoms.
3. The process of claim 2 wherein the amphiphilic moiety comprises a hydroxyl or alkoxy-containing organic compounds having at least about 4 carbon atoms.
4. The process of claim 3 wherein the amphiphilic moiety comprises a hexahydrotriazine substituted with hydroxyalkyl and alkoxyalkylene groups of 1 to 20 carbon atoms.
5. The process of claim 4 wherein the amphiphilic moiety comprises at least one of MEA triazine, MOPA triazine, and 1,3,5 (tris-methoxyethyl) hexahydrotriazine and partially or fully spent derivatives thereof; benzyl alcohol, benzyl ethers of 1 to 6 carbons; phenol; and alkylphenolalkoxylates of up to 30 carbons.
6. A process for reducing an amount of sulfhydryl moieties in hydrocarbon streams comprising contacting in the presence of water a composition comprising MEA triazine and at least one of MMA triazine and MOPA triazine for a time sufficient to provide a spent triazine in which at least one hetero nitrogen atom is replaced with a sulfur atom, wherein each of the MEA triazine and MMA triazine are provided in an amount sufficient to avoid the formation of solids.
7. The process of claim 6 wherein the composition comprises MEA triazine and MOPA triazine.
8. The process of claim 7 wherein the mole ratio of MOPA triazine to MEA triazine is in the range of about 1:4 to 1:25.
9. The process of claim 6 wherein the composition comprises MEA triazine and MMA triazine.
10. The process of claim 6 wherein the mole ratio of MMA triazine to MEA triazine is in the range of about 1:4 to 1:25.