Materials and methods for suppression of filamentous coke formation

Abstract

Materials and methods for inhibiting the formation of filamentous coke on heated metal surfaces. Organoselenium compounds, including diarylselenides, diaryldiselenides, alkylarylselenides, and alkylaryldiselenides, are employed as hydrocarbon feedstock additives or as hydrocarbon fuel additives to inhibit filamentous coke formation on hydrocarbon processing systems, including reactors, furnaces, engines and parts thereof and in particular to inhibit filamentous coke formation on heat-exchangers in such systems.

We claim:  
     
         1 . A hydrocarbon feedstock or hydrocarbon fuel composition exhibiting reduced levels of filamentous coke formation at a temperature above about 300° C. which comprises a hydrocarbon feedstock or a hydrocarbon fuel and an organoselenium compound present between about 0.01 ppm selenium and about 1000 ppm selenium with respect to the hydrocarbon.  
     
     
         2 . The composition of  claim 1  wherein the organoselenium compound is present at a level less than or equal to about 100 ppm selenium.  
     
     
         3 . The composition of  claim 1  wherein the organoselenium compound is present at a level ranging from about 1 ppm selenium to about 50 ppm selenium.  
     
     
         4 . The composition of  claim 1  wherein the organoselenium compound is present at a level less than or equal to about 10 ppm selenium.  
     
     
         5 . The composition of  claim 1  wherein the organoselenium compound is selected from the group consisting of a dialkylselenide, a diarylselenide, a dialkyldiselenide, a diaryldiselenide, an alkylarylselenide, an alkylaryldiselenide, a diaklylselenohalide, an alkylselenol, and an arylselenol.  
     
     
         6 . The composition of  claim 1  wherein the organoselenium compound is diphenylselenide.  
     
     
         7 . The composition of  claim 6  wherein the diphenylselenide is present at a level ranging from about 1 ppm selenium to about 30 ppm selenium.  
     
     
         8 . The composition of  claim 1  wherein the organoselenium compound is selected from the group consisting of diphenylselenide, diphenyldiselenide, dibenzylselenide, or benzylselenol.  
     
     
         9 . The composition of  claim 1  also exhibiting prevention of filamentous coke formation at a temperature above about 300° C.  
     
     
         10 . The composition of  claim 1  also exhibiting removal of coke deposits at a temperature above about 300° C.  
     
     
         11 . The composition of  claim 1  exhibiting reduced levels of filamentous coke formation on a surface comprising metal or alloy, said metal or alloy containing iron or nickel or both.  
     
     
         12 . The composition of  claim 1  wherein the hydrocarbon fuel is a fuel for an engine, a propulsion system, or a hypersonic aircraft.  
     
     
         13 . The composition of  claim 1  wherein the hydrocarbon feedstock is a feedstock for a pyrolysis furnace or a reactor.  
     
     
         14 . The composition of  claim 13  wherein the pyrolysis furnace is a cracking furnace for ethylene production.