Oil miscible additive compositions for mercury removal from liquid hydrocarbons

Abstract

The present application relates generally to processes, systems, and compositions for removing mercury from liquid hydrocarbons. In one embodiment, the application pertains to a method for removing mercury from hydrocarbons. The method comprises reacting a mercury species within the hydrocarbons with an additive composition to produce a reaction product. The reaction product typically comprises a different speciation for mercury than the original mercury species. The reaction product is then removed from the hydrocarbons. The additive composition employed comprises a sulfur or heteroatom donating substance and a substantially oil-soluble solvent.

What is claimed is: 
     
         1 . A method for removing mercury from hydrocarbons, comprising:
 reacting a mercury species within the hydrocarbons with an additive composition to produce a reaction product wherein the reaction product comprises a different speciation for mercury than the mercury species; and   removing at least a portion of the reaction product from the hydrocarbons;   
       wherein the additive composition comprises an effective amount of a sulfur or heteroatom donating substance and a solvent which is substantially miscible with oil wherein the heteroatom is nitrogen, sulfur, oxygen, or a mixture thereof. 
     
     
         2 . The method of  claim 1 , wherein the additive composition further comprises water. 
     
     
         3 . The method of  claim 1 , wherein the sulfur or heteroatom donating substance comprises a sulfide, a thiolate functionalized solid, a thiol, a dithiol, a dithiocarbamate, or any combination thereof. 
     
     
         4 . The method of  claim 3 , wherein the sulfur or heteroatom donating substance comprises the thiol, the dithiol, or the dithiocarbamate, or any combination thereof and wherein the sulfur or heteroatom donating substance further comprises a polymer. 
     
     
         5 . The method of  claim 3 , wherein the sulfide is Na 2 S, (NH 4 ) 2 S, a polysulfide having the formula MSx wherein M is selected from Na 2 , K 2 , or Ca, or any combination thereof. 
     
     
         6 . The method of  claim 3 , wherein the thiolate functionalized solid comprises self-assembled monolayers on mesoporous supports (SAMMS), a functionalized silica gel (SiliaMetS), or any combination thereof. 
     
     
         7 . The method of  claim 3 , wherein the dithiol comprises 1,3,4-thiadiazole-2,5-dithiol (TDT). 
     
     
         8 . The method of  claim 1 , wherein the solvent comprises a glycol, an alcohol, or any mixture thereof. 
     
     
         9 . The method of  claim 8  wherein the glycol comprises a polyalkylene glycol. 
     
     
         10 . The method of  claim 8 , wherein the glycol comprises dipropylene glycol methyl ether, 2-butoxyethanol, or any combination thereof. 
     
     
         11 . The method of  claim 8 , wherein the alcohol comprises isopropyl alcohol. 
     
     
         12 . The method of  claim 1 , wherein the additive composition comprises a concentration of the sulfur or heteroatom donating substance which is less than a saturation concentration of the sulfur or heteroatom donating substance in the additive composition. 
     
     
         13 . The method of  claim 1 , wherein the hydrocarbons comprise a crude, a condensate, a slop oil, a distillate, or any combination thereof. 
     
     
         14 . The method of  claim 1 , wherein the additive composition is a component of a wash water solution that is mixed with the hydrocarbons in a mixing vessel 
     
     
         15 . The method of  claim 1 , wherein the additive composition is added to a feed of the hydrocarbons before the hydrocarbons are introduced into a reactor. 
     
     
         16 . The method of  claim 1 , wherein the hydrocarbons and the additive composition are introduced into a reactor on a continuous basis. 
     
     
         17 . The method of  claim 1 , wherein the hydrocarbons and the additive composition are introduced into a reactor and are mixed in a batch process. 
     
     
         18 . The method of  claim 1 , wherein the reaction of the mercury species with the hydrocarbons with the additive composition is performed in a dedicated reactor, in a mixing tank, in a pipe with a static mixer, in a pipe with equipment or bends for mixing and residence time, or any combination thereof. 
     
     
         19 . The method of  claim 18  wherein the dedicated reactor is a continuous stirred tank reactor. 
     
     
         20 . The method of  claim 1 , wherein the reaction product is a precipitate and wherein the removing comprises a solid-liquid separation process. 
     
     
         21 . The method of  claim 20 , wherein the solid-liquid separation process comprises filtration, centrifugation, sedimentation, flotation, or any combination thereof. 
     
     
         22 . The method of  claim 1 , wherein the removing comprises an extraction process comprising desalting, water washing, sulfidic extraction, pH adjustment, or any combination thereof. 
     
     
         23 . The method of  claim 1 , wherein the removing is conducted in the absence of desalting. 
     
     
         24 . The method of  claim 1 , wherein the additive composition further comprises a phase transfer agent. 
     
     
         25 . The method of  claim 24 , wherein the phase transfer agent comprises an oil soluble cation salt. 
     
     
         26 . The method of  claim 24 , wherein the phase transfer agent comprises a quaternary ammonium salt, a quaternary phosphonium salt, an imidazolium salt, or any combination thereof. 
     
     
         27 . The method of  claim 26 , wherein the quaternary ammonium salt comprises an alkyl ammonium salt, an aryl ammonium salt, or any combination thereof. 
     
     
         28 . The method of  claim 27 , wherein the quaternary ammonium salt comprises tetrabutylammonium chloride (TBAC). 
     
     
         29 . A composition comprising:
 water;   a sulfur or heteroatom donating substance; and   an amount of a solvent which is substantially miscible with oil, wherein the amount of the solvent is sufficient to dissolve at least a portion of the sulfur or heteroatom donating substance and wherein a concentration of the sulfur or heteroatom donating substance in the composition is less than a saturation concentration of the sulfur or heteroatom donating substance in the composition.   
     
     
         30 . The composition of  claim 29  wherein the solvent comprises dipropylene glycol methyl ether, 2-butoxyethanol, isopropyl alcohol, or any combination thereof. 
     
     
         31 . The composition of  claim 29 , which further comprises a hydrocarbon and one or more mercury compounds. 
     
     
         32 . The composition of  claim 29 , which further comprises a phase transfer agent.