Process, Method, and System for Removing Heavy Metals from Oily Solids

Abstract

Oil is recovered from a mercury containing oily solids by mixing the solids with at least a treating agent selected from selected from flocculants, sulfidic compounds, demulsifiers, and combinations thereof, and optionally a solvent, forming a mixture. The mixture is then separated to recover a first phase containing treated oil having less than 50% of the original amount of mercury in the oily solids, and a second phase containing treated solids having a reduced concentration of mercury. The oily solids are selected from drilling muds; oily sediments coating inside of pipelines; sediment deposits on crude oil tanks, vessels, and separators; surface coating on equipment; slop oil from upstream operations; oily solids from heavy oil processing operations; solids recovered from processes for removing mercury from hydrocarbon materials; spill clean-up materials; and mixtures thereof.

1 . A process to recover oil from oily solids containing a first amount of mercury and first concentration of mercury, the process comprising:
 mixing the oily solids containing mercury with a treating agent in an amount from 0.001-10 wt % based on weight of the oily solids, forming a mixture, wherein the treating agent is selected from flocculants, sulfidic compounds, demulsifiers, and combinations thereof;   separating the mixture to recover a first phase containing treated oil having less than 50% of the first amount of mercury and a second phase containing treated solids having a second amount of mercury, wherein the second amount of mercury is less than the first amount.   
     
     
         2 . The process of  claim 1 , wherein the first concentration of mercury in the oily solids is greater than 50% meta-cinnabar as determined by Reitveld XRD refinement. 
     
     
         3 . The process of  claim 1 , the recovered treated oil has a mercury concentration of less than 100 ppbw. 
     
     
         4 . The process of  claim 1 , further comprising
 adding to the oily solids at least a solvent selected from water, light hydrocarbon material, and crude oil at a weight ratio of solvent to oily solids of 15:1 to 10,000:1;   wherein the solvent is added prior to separating the mixture to recover a first phase;   
       and wherein the first phase contains a mixture of treated oil in the solvent. 
     
     
         5 . The process of  claim 4 , further comprising separating the mixture of treated oil and solvent to recover treated oil having less than 50% of the first amount of mercury and the solvent containing at least 50% of the first amount of mercury. 
     
     
         6 . The process of  claim 5 , wherein the solvent is water and wherein the separation is carried out by any of gravity separation, filtration, centrifugation, hydrocyclones, and combinations thereof. 
     
     
         7 . The process of  claim 1 , wherein the treating agent is a sulfur compound which when dissolved in water, yields at least one of S 2− , SH − , S x H 2− , and S x H −  anions, and wherein the sulfur compound converts mercury to soluble mercury complexes. 
     
     
         8 . The process of  claim 7 , wherein the sulfur compound is selected from potassium sulfide, sodium sulfide (Na 2 S), sodium hydrosulfide (NaSH), potassium polysulfide, sodium polysulfide (Na 2 Sx), ammonium sulfide [(NH 4 ) 2 S], ammonium hydrosulfide (NH 4 HS), ammonium polysulfide [(NH 4 ) 2 Sx], Group 1 and Group 2 counterparts of these materials, and combinations thereof. 
     
     
         9 . The process of  claim 1 , wherein the treating agent is a water treating polymer which removes dissolved minerals from water by complexing with the minerals. 
     
     
         10 . The process of  claim 9 , wherein the water treating polymer is selected from nonionic polymers, anionic polymers, cationic polymers, copolymers having any of functional groups acrylamide, acrylic acid, amine, acrylate, ethylene imine, ethylene oxide, and mixtures thereof. 
     
     
         11 . The process of  claim 9 , wherein the water treating polymer is selected from aluminum chlorohydrate, prism polymers, sulfonate-based polymers, and mixtures thereof. 
     
     
         12 . The process of  claim 1 , wherein the treating agent is a demulsifier selected from polyamines; polyamidoamines; polyimines; condensates of o-toluidine and formaldehyde; quaternary ammonium compounds; ionic surfactants; polyoxyethylene alkyl phenols, their sulphonates and sodium sulphonates thereof; polyalkoxylate block copolymers and ester derivatives; alkylphenol-aldehyde resin alkoxylates; polyalkoxylates of polyols or glycidyl ethers; polyamine polyalkoxylates and related cationic polymers; polyurethanes (carbamates) and polyalkoxylate derivatives; hyperbranched polymers; vinyl polymers; polysilicones; and mixtures thereof. 
     
     
         13 . The process of  claim 12 , wherein the demulsifier is a polyamine. 
     
     
         14 . The process of  claim 1 , wherein the oily solids are selected from any of drilling muds from drilling operations; oily sediments coating inside of pipelines; sediment deposits on crude oil tanks, vessels, and separators; surface coating on equipment; slop oil from upstream operations; slop oil from waste processing facilities; oily solids from heavy oil processing operations; solids recovered from processes for removing mercury from hydrocarbon materials; spill clean-up materials; and mixtures thereof. 
     
     
         15 . The process of  claim 14 , wherein the oily solids comprise particulates selected from activated carbon, polymeric materials, and diatomaceous earth recovered from mercury removal filtration units for removing mercury from hydrocarbons. 
     
     
         16 . The process of  claim 1 , wherein the treating agent is sodium hydrosulfide. 
     
     
         17 . A process to recover oil from oily solids containing a first amount of mercury, the process comprising:
 mixing the oily solids containing mercury with at least a treating agent selected from flocculants, sulfidic compounds, demulsifiers, and combinations thereof, forming a mixture, wherein the treating agent is present in an amount ranging from 0.001 wt % and 10 wt % based on weight of the oily solids;   adding a sufficient amount of hydrocarbon material to the mixture for a weight ratio of hydrocarbon material to oily solids of 50:1 to 2000:1;   separating the mixture to recover a first phase containing treated oil and hydrocarbon material having less than 50% of the first amount of mercury and a second phase containing treated solids having a second amount of mercury, wherein the second amount of mercury is less than the first amount.   
     
     
         18 . The process of  claim 17 , wherein the treating agent is a flocculant selected from water treating polymers. 
     
     
         19 . The process of  claim 18 , wherein the water treating polymer is cationic polyacrylamide. 
     
     
         20 . A process to recover oil from oily solids containing a first amount of mercury, the process comprising:
 mixing the oily solids containing a first amount of mercury with water and a treating agent selected from flocculants, sulfidic compounds, demulsifiers, and combinations thereof, forming a mixture, wherein the treating agent is present in an amount ranging from 0.001 wt % and 10 wt % based on weight of the oily solids, and the water is added in a sufficient amount for a weight ratio of water to oily solids of 50:1 to 2000:1;   separating the mixture for a first phase containing treated oil in water and a second phase containing treated solids having a second amount of mercury, wherein the second amount of mercury is less than the first amount of mercury;   separating the first phase containing treated oil in water to recover a first stream containing water having more than 50% of the first amount of mercury and a second stream containing treated oil having less than 50% of the first amount of mercury.   
     
     
         21 . The process of  claim 20 , wherein the treating agent is a sulfur compound which when dissolved in the water, yields S 2− , SH − , S x   2− , or S x H −  anions. 
     
     
         22 . The process of  claim 21 , wherein the sulfur compound is selected from sodium polysulfide, ammonium polysulfide, sulfide-containing polymer, alkali sulfides, alkali hydrosulfides, ammonium sulfides, and mixtures thereof. 
     
     
         23 . The process of  claim 20 , further comprising injecting the recovered first stream containing water into a depleted oil or gas reservoir. 
     
     
         24 . The process of  claim 20 , further comprising recycling the recovered first stream containing water as dilution fluid for injection into an oil or gas reservoir. 
     
     
         25 . The process of  claim 20 , wherein the water treating polymer is cationic polyacrylamide.