Process for treatment of crude oil, sludges, and emulsions

Abstract

The present invention provides a process for treatment of petroleum/crude sludge for removal of bound and unbound water thereby facilitating recovery of non volatiles free product hydrocarbons in a range of about 96 wt. % to 100 wt. % along with unbound water having turbidity at least below 20 NTU. The process for treatment of sludge facilitates recovery of almost 100% solvent along with entire bound water in a range of about 99 wt % to 100 wt %. The process for treatment of sludge facilitates recovery of free water in a range of about 94 wt. % to 99 wt. %. The process for treatment of sludge also facilitates recovery of solvent to be reused in said process. The present invention further provides a process for treatment slop oil containing water, solids, salts and limited hydrocarbon content less than 10,000 PPM for recovering usable water therefrom by an effective and economically viable process. The process for treatment of slop oil is capable of bringing down turbidity value thereof in a range of 90 wt. % to 99 wt. %.

1 . A process for treatment of a sludge mixture having hydrocarbons with bound water, unbound water, dissolved and un-dissolved solids therein, the process for treatment of the sludge mixture comprising the steps of:
 a) Centrifuging the sludge mixture in a first centrifuge provided the sludge mixture splits into various components, the first centrifuge being a batch or Multi-Pass centrifuge, the said centrifuge forming a viscous hydrocarbon layer, a slop oil layer and a free flowing hydrocarbon layer;   b) Desalting the viscous hydrocarbon layer from step a) in a first desalter followed by optional treatment thereof in a heat based low volatiles stripping vessel for removing vapors of low boiling liquid hydrocarbons therefrom;   c) Condensing the vapors of low boiling liquid hydrocarbons from step b) in a first condenser for obtaining low boiling liquid hydrocarbons along with water for use;   d) Optionally desalting crude hydrocarbons coming from a group collection center in a second desalter for obtaining desalted product crude and removal of a bound water containing hydrocarbon layer followed by mixing the bound water containing hydrocarbon layer with the viscous hydrocarbon layer from the first centrifuge;   e) Desalting the free flowing hydrocarbon layer from step a) in a third desalter for entire removal of salts therefrom;   f) Homogenizing the viscous hydrocarbon layer from step b) in a homogenizer by adding a first predefined amount of solvent for forming a volatiles free non-viscous homogenized stream therefrom;   g) Performing BTX and Ash tests of the non-viscous homogenized stream from step f) followed by treatment thereof in an agitator cum homogenizer thereby adding a second predefined amount of solvent therein in accordance with the BTX and Ash tests results;   h) Centrifuging the non-viscous homogenized stream from step g) in a second centrifuge for separating a bound water dominant hydrocarbon stream, an unbound water dominant or water free hydrocarbon stream and the slop oil therefrom;   i) Optionally treating the non-viscous homogenized stream from step g) in a hot insulated settling tank for removal of water free solvent along with hydrocarbons therefrom;   j) Heating the unbound water dominant or water free hydrocarbon stream from step h) in a first heating vessel thereby optionally adding a predefined amount of free water therein, the first heating vessel operating at a first predefined temperature range thereby forming a first residual phase and a first vapor phase therein;   k) Heating the bound water dominant hydrocarbon stream from step h) in a second heating vessel at a second temperature range thereby optionally adding a third predefined amount of additional solvent therein, the second heating vessel forming a second residual phase and a second vapor phase therein;   l) Centrifuging the first residual phase from step j) in a hot centrifuge at a second predefined temperature for obtaining volatiles free desalted product hydrocarbons in a range of about 96 wt % to 100 wt % along with unbound water having turbidity at least below 20 NTU;   m) Treating the second residual phase from step k) in the first heating vessel; and   n) Condensing the first vapor phase from step j) and the second vapor phase from step k) through a second condenser for obtaining almost 100% solvent, the bound water in a range of about 99 wt % to 100 wt % wherein the free water in a range of about 94 wt. % to 100 wt. % is collected through the entire process, the solvent being reused in said process.   
     
     
         2 . The process for treatment of the sludge mixture as claimed in  claim 1 , wherein the first centrifuge substantially reduces the quantum of the sludge mixture with bound water that facilitates further processing with reduced cost and time in downstream processing of said process. 
     
     
         3 . The process for treatment of the sludge mixture as claimed in  claim 1 , wherein the free flowing hydrocarbon layer is about 41 wt % typically having 3,864 ppm water and 0.88 wt. % ash with calorific value of 10,635 kcal/kg. 
     
     
         4 . The process for treatment of the sludge mixture as claimed in  claim 1 , wherein the viscous hydrocarbon layer has at least 42.21 wt. % water typically having 8.61 wt. % Ash with CV of 5,210 kcal/kg. 
     
     
         5 . The process for treatment of the sludge mixture as claimed in  claim 1 , wherein the first centrifuge enhances separation between the components present in the sludge by extending a period of residence time of the sludge thereby gradually varying revolutions per minute of the batch centrifuge enabling collection of slop oil behind the viscous hydrocarbon layer. 
     
     
         6 - 7 . (canceled) 
     
     
         8 . The process for treatment of the sludge mixture as claimed in  claim 1 , wherein the first desalter, the second desalter and the third desalter prevent ingression of water into various product hydrocarbon streams in refineries thereby preventing accumulation of sludge downstream of said process and in vessels utilized in refinery onward processes. 
     
     
         9 - 11 . (canceled) 
     
     
         12 . The process for treatment of the sludge mixture as claimed in  claim 1 , wherein removal of the bound water from the hydrocarbon layer allows removal of heavy metal, ash and salts therefrom for effectively improving commercial value. 
     
     
         13 . The process for treatment of the sludge mixture as claimed in  claim 1 , wherein the BTX and Ash tests help assist in determination of an optimum amount of solvent to be added in said process. 
     
     
         14 . The process for treatment of the sludge mixture as claimed in  claim 1 , wherein the solvent reduces viscosity for removal of bound water from topmost layer of the non-viscous homogenized stream on account of viscosity. 
     
     
         15 . The process for treatment of the sludge mixture as claimed in  claim 1 , wherein the solvent assists in homogenization of the sludge that in turn helps in sampling and accurate determination of water and ash content. 
     
     
         16 . The process for treatment of the sludge mixture as claimed in  claim 1 , wherein the solvent is added in said process only for viscous portion of the hydrocarbons which substantially reduces overall use of solvent in said process. 
     
     
         17 . The process for treatment of a sludge mixture as claimed in  claim 1 , wherein the solvent is selected from the group of Benzene, Toluene, Xylene and similar solvents which can form azeotropes with water. 
     
     
         18 . (canceled) 
     
     
         19 . The process for treatment of the sludge mixture as claimed in  claim 1 , wherein the solvent¾tream and the second centrifuge mutually remove substantial bound water from the viscous hydrocarbon layer at an ambient temperature. 
     
     
         20 . The process for treatment of the sludge mixture as claimed in  claim 1 , wherein the solvent depresses the boiling point of the bound water. 
     
     
         21 . The process for treatment of the sludge mixture as claimed in  claim 1 , wherein the solvent is added in a range of about 1.8 to 100 times the weight of water present in the sludge for entire removal of the bound water. 
     
     
         22 . The process for treatment of the sludge mixture as claimed in  claim 1 , wherein the solvent has a left over weight ratio of solvent to hydrocarbon in a minimum range of 2.00 to 6.00 for entire removal of the bound water at least temperature. 
     
     
         23 . The process for treatment of the sludge mixture as claimed in  claim 1 , wherein the first predefined temperature of the first heating vessel is in a range of about 90° C.-105° C. 
     
     
         24 . The process for treatment of the sludge mixture as claimed in  claim 1 , wherein, the hot centrifuge has a temperature in a range of about 80° C. to 94° C. 
     
     
         25 . The process for treatment of the sludge mixture as claimed in  claim 1 , wherein the hot centrifuge is a hot settling tank that ensures adequate reduction in viscosity of hydrocarbons thereby allowing settling of free water therein over a predefined period of time. 
     
     
         26 . The process for treatment of the sludge mixture as claimed in  claim 25 , wherein the hot settling tank is operated under high pressure for increasing the operating temperature range for further reducing the viscosity of the hydrocarbon thereby facilitating faster removal of free water without leading to boiling of water therein. 
     
     
         27 . process for treatment of the sludge mixture as claimed in  claim 1 , wherein the second heating vessel is preferably a multi effect evaporator preferably with a thermal vapor recompression to avoid thermal cracking of the product hydrocarbon stream. 
     
     
         28 . The process for treatment of the sludge mixture as claimed in  claim 1 , wherein one or both of the first and second heating vessel includes a foam breaker and an entrainment separator adapted to avoid entrainment of hydrocarbons in condensate, and optionally the first and second heating vessels are provided with waste heat for reducing cost of energy in said process. 
     
     
         29 . (canceled) 
     
     
         30 . The process for treatment of the sludge mixture as claimed in  claim 1 , wherein the second heating vessel maintain a controlled rate of heating with an optimum ratio of residual solvent to dehydrated Hydrocarbon for complete removal of bound water from the hydrocarbon. 
     
     
         31 . The process for treatment of the sludge mixture as claimed in  claim 1 , wherein the bound water obtained is high quality usable water that requires minimal treatment for being used as a drinking water. 
     
     
         32 - 33 . (canceled) 
     
     
         34 . A process for treatment of slop oil containing water, solids, salts, and hydrocarbons with or without bound water, the process comprising the steps of:
 a) Centrifuging the slop oil through a fourth centrifuge for obtaining the slop oil with low turbidity by connecting most oil present in a thin top layer;   b) Treating the above slop oil from step a) in a high speed shear mixer by adding a solvent to form a mixture followed by centrifuging thereof in a fifth centrifuge for obtaining a water dominant hydrocarbon layer and a solvent dominant hydrocarbon layer therefrom;   c) Performing BTX and Ash tests of the solvent dominant hydrocarbon layer from step b) for bound water therein followed by a heat treatment thereof in a third heating vessel and a fourth heating vessel, the third vessel having a predefined amount of solvent added therein, the fourth vessel having a predefined amount of free water added therein, the third heating vessel and fourth heating vessel separating a vapor phase from a liquid phase, the vapor phase having entire remaining solvent and part of free water therein, the liquid phase having hydrocarbons with limited solids, limited salts, free water and alum therein;   d) Centrifuging the liquid phase from step c) through a sixth centrifuge operating at a predefined temperature for separating a product hydrocarbon layer from a water layer, the water layer having limited salts, limited solids and alum therein;   e) Treating the water layer from step d) through a first reverse osmosis plant for obtaining water for use and a reject stream therefrom;   f) Condensing the vapor phase from step c) through a third condenser for obtaining solvent for being reused in the high speed shear mixer and water for use therefrom;   g) Heating the water dominant hydrocarbon layer from step b) in a fifth heating vessel for separating vapors of solvent therefrom followed by condensing thereof in the third condenser to obtain solvent for reuse and water for use therefrom, the fifth heating vessel producing a liquid phase having remaining water, limited hydrocarbons; salts and solids with a substantially low turbidity;   h) Treating the liquid phase from step g) in a settling tank followed by addition of a predefined amount of alum therein, the settling tank forming a water dominant alum layer and a gelatinous oil bearing layer therein;   i) Filtering the water dominant alum layer from step h) in a filtration unit, the filtration unit separating the water dominant alum layer into a filtrate stream and a residual stream, the filtrate stream having water, alum and salts therein, the residual stream having wet solids with traces of hydrocarbons, salts and alum therein;   j) Treating the filtrate stream from step i) in a second reverse osmosis plant for recovering usable water therefrom;   k) Mixing the residual stream from step i) with the gelatinous oil bearing layer followed by drying thereof in a first hot dryer for obtaining a viscous liquid containing hydrocarbons, alum, solids and salts;   l) Agitating the viscous liquid from step k) in an agitator cum de-oiling unit by adding a predefined solvent therein followed by treatment thereof through a seventh centrifuge for obtaining a water layer, a cake layer and a solvent layer thereby adding water therein, the water layer having alum, salts and limited solvent therein, the cake layer having cake of de-oiled solids with solvent, limited salts and limited alum therein;   m) Treating the water layer from step l) in a sixth heating vessel for obtaining vapors of solvent and water followed by treatment thereof through a fourth condenser for obtaining solvent for reuse and water for use or further treatment in said process;   n) Treating the solvent layer from step l) in the fourth heating vessel for recovery of solvent therefrom; and   o) Treating the cake layer from step l) in a second hot dryer for recovery of solvent through the condenser, the second hot dryer producing dried de-oiled solids having traces of alum and salts therein.   
     
     
         35 - 59 . (canceled) 
     
     
         60 . A process for treatment of a sludge mixture comprising of a centrifuge, the process for treatment comprising the steps of:
 Centrifuging the sludge containing hydrocarbons, bound and unbound water, salts and solids in a centrifuge to break the binding between the components present by increasing residence time of the sludge in the centrifuge thereby forming a viscous hydrocarbon layer with bound water, salts and solids, a free flowing hydrocarbons layer with limited salts and solids and a free water layer with limited solids and salts, the centrifuge repositioning the viscous hydrocarbon layer from a back side to a middle side therein by slowly increasing revolutions per minutes thereof, the centrifuge slowly decreasing an angle between a vertical axis of a container and a horizontal plane thereof thereby gradually reducing but not allowing said angle to become 0°.   
     
     
         61 - 62 . (canceled) 
     
     
         63 . A process for treatment of sludge mixture with combined effect of centrifuge and solvent, the sludge mixture containing bound and unbound water, salts and solids therein, the process for treatment comprising the steps of:
 a) Adding a predefined amount of solvent in the viscous hydrocarbon layer from step a), followed by mixing thereof, the solvent reducing the viscosity of the viscous hydrocarbon layer.   b) Centrifuging the solvent dominant viscous hydrocarbon layer from step a) in the centrifuge to obtain a large layer of solvent and hydrocarbon, a layer containing hydrocarbons and bound water and a free water layer, the centrifuge having an extended residence time to produce less sludge with bound water therein;   c) Treating the large layer of solvent and hydrocarbon in step b) to recover solvent by boiling through free water in a temperature range of 90° C. to 99° C. at an atmospheric pressure.   
     
     
         64 - 65 . (canceled)