Heavy amines as hydrogen sulfide and mercaptan scavengers

Abstract

The present invention generally relates to compositions and methods for scavenging hydrogen sulfide and/or mercaptans from fluids. More particularly, the invention relates to the use of compositions comprising a surfactant and the reaction product between a polyamine and a formaldehyde as a hydrogen sulfide or a mercaptan scavenger for hydrocarbon-containing fluids, particularly for natural gas, crude oil, field oil, fuel oil, naphtha, gasoline, kerosene, diesel, slurry oil, gas oil, resid, refinery gas, coal gas, tar, asphalt, coke gas, ammonia synthesis gas, gas from an industrial gas stream, or a sulfurization plant.

1 . A method of reducing the amount of hydrogen sulfide or mercaptans in a hydrocarbon-containing fluid, the method comprising contacting an effective amount of a scavenger composition with the hydrocarbon-containing fluid, the scavenger composition comprising a surfactant and a reaction product of a polyamine and formaldehyde. 
     
     
         2 . The method of  claim 1 , wherein the hydrocarbon-containing fluid comprises crude oil, field oil, asphalt, naphtha, gasoline, kerosene, diesel, natural gas, refinery gas, coal gas, coke gas, ammonia synthesis gas, gas from a sulfurization plant, or an industrial gas stream. 
     
     
         3 . The method of  claim 1 , wherein the hydrocarbon-containing fluid is crude oil. 
     
     
         4 . The method of  claim 1 , wherein the polyamine comprises ethylenediamine, propylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, tetrabutylenepentamine, hexaethyleneheptamine, hexapentyleneheptamine, heptaethyleneoctamine, octaethylenenonamine, nonaethylenedecamine, decaethyleneundecamine, decahexyleneundecamine, undecaethylenedodecamine, dodecaethylenetridecamine, tridecaethylenetetradecamine, N-tallow propylenediamine, or a combination thereof. 
     
     
         5 . The method of  claim 4 , wherein the polyamine comprises diethylenetriamine, tetraethylenepentamine, or a combination thereof. 
     
     
         6 . The method  claim 1 , wherein the reaction product has a molar ratio of formaldehyde to polyamine of 0.1:1 to 25:1 
     
     
         7 . The method of  claim 6 , wherein the polyamine comprises diethylenetriamine, tetraethylenepentamine, or a combination thereof and the reaction product has a molar ratio of formaldehyde to polyamine of 0.4:1 to 2:1. 
     
     
         8 . The method of  claim 1 , wherein the surfactant comprises a quaternary ammonium compound, a trialkylamine oxide, or a combination thereof. 
     
     
         9 . The method of  claim 8 , wherein the surfactant comprises a tetraalkyl ammonium chloride, a tetraalkyl ammonium sulfate, a (C 8 -C 20 alkyl)di(C 1 -C 4 alkyl) amine oxide, ethoxylated C 4 -C 14  alcohol, or a combination thereof. 
     
     
         10 . The method of  claim 8 , wherein the surfactant comprises tetralkyl ammonium chloride. 
     
     
         11 . The method of  claim 1 , wherein the surfactant is added to the scavenger composition at a concentration of from about 1 to about 10 wt. %, based on the total weight of the scavenger composition. 
     
     
         12 . The method of  claim 11 , wherein the surfactant is added to the scavenger composition at a concentration of from about 1 to about 5 wt. %, based on the total weight of the scavenger composition. 
     
     
         13 . The method of  claim 11 , wherein the surfactant comprises a tetraalkyl ammonium chloride, a tetraalkyl ammonium sulfate, a (C 8 -C 20 alkyl)di(C 1 -C 4 alkyl) amine oxide, ethoxylated C 4 -C 14  alcohol, or a combination thereof and is added to the scavenger composition at a concentration of from about 4 to about 6 wt. %, based on the total weight of the scavenger composition. 
     
     
         14 . The method of  claim 1 , wherein the scavenger composition is contacted with the hydrocarbon-containing fluid at a concentration from 0.2 to 0.8 ppm per 1 ppm of hydrogen sulfide or mercaptan detected in the vapor space of the hydrocarbon-containing fluid. 
     
     
         15 . The method of  claim 14 , wherein the scavenger composition is contacted with the hydrocarbon-containing fluid at a concentration from 0.4 to 0.8 ppm per 1 ppm of hydrogen sulfide or mercaptan detected in the vapor space of the hydrocarbon-containing fluid. 
     
     
         16 . The method of  claim 1 , wherein the scavenger composition is contacted with the hydrocarbon-containing fluid at a temperature from about 20° C. to about 290° C. 
     
     
         17 . The method of  claim 16 , wherein the scavenger composition is contacted with the hydrocarbon-containing fluid at a temperature from about 20° C. to about 100° C. 
     
     
         18 . The method of  claim 1 , wherein the rate of reaction between the hydrogen sulfide or mercaptan and the reaction product of a polyamine and formaldehyde is increased using the scavenger composition as compared to the rate of reaction using the reaction product of a polyamine and formaldehyde in the absence of the surfactant. 
     
     
         19 . The method of  claim 18 , wherein the increased rate of reaction is demonstrated by a reduction in the hydrogen sulfide or mercaptan concentration of or more times during a residence time of 2 hours at 100° C. 
     
     
         20 . The method of  claim 18 , wherein the increased rate of reaction is demonstrated by a reduction in the hydrogen sulfide or mercaptan concentration of 8, or more times during a residence time of 2 hours at 100° C.