US20150322348A1 - Process for treatment of crude oil, sludges, and emulsions - Google Patents

Process for treatment of crude oil, sludges, and emulsions Download PDF

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US20150322348A1
US20150322348A1 US14/652,014 US201314652014A US2015322348A1 US 20150322348 A1 US20150322348 A1 US 20150322348A1 US 201314652014 A US201314652014 A US 201314652014A US 2015322348 A1 US2015322348 A1 US 2015322348A1
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water
solvent
sludge
layer
treatment
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Dhruva Jyoti Dasgupta
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Nagaarjuna Shubho Green Technologies Private Ltd
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    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
    • C10G1/00—Production of liquid hydrocarbon mixtures from oil-shale, oil-sand, or non-melting solid carbonaceous or similar materials, e.g. wood, coal
    • C10G1/002—Production of liquid hydrocarbon mixtures from oil-shale, oil-sand, or non-melting solid carbonaceous or similar materials, e.g. wood, coal in combination with oil conversion- or refining processes
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
    • C10G31/00—Refining of hydrocarbon oils, in the absence of hydrogen, by methods not otherwise provided for
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/02—Treatment of water, waste water, or sewage by heating
    • C02F1/04—Treatment of water, waste water, or sewage by heating by distillation or evaporation
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F11/00—Treatment of sludge; Devices therefor
    • C02F11/12—Treatment of sludge; Devices therefor by de-watering, drying or thickening
    • C02F11/121—Treatment of sludge; Devices therefor by de-watering, drying or thickening by mechanical de-watering
    • C02F11/127—Treatment of sludge; Devices therefor by de-watering, drying or thickening by mechanical de-watering by centrifugation
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F11/00—Treatment of sludge; Devices therefor
    • C02F11/12—Treatment of sludge; Devices therefor by de-watering, drying or thickening
    • C02F11/14—Treatment of sludge; Devices therefor by de-watering, drying or thickening with addition of chemical agents
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
    • C10G1/00—Production of liquid hydrocarbon mixtures from oil-shale, oil-sand, or non-melting solid carbonaceous or similar materials, e.g. wood, coal
    • C10G1/04—Production of liquid hydrocarbon mixtures from oil-shale, oil-sand, or non-melting solid carbonaceous or similar materials, e.g. wood, coal by extraction
    • C10G1/045—Separation of insoluble materials
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
    • C10G31/00—Refining of hydrocarbon oils, in the absence of hydrogen, by methods not otherwise provided for
    • C10G31/08—Refining of hydrocarbon oils, in the absence of hydrogen, by methods not otherwise provided for by treating with water
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
    • C10G31/00—Refining of hydrocarbon oils, in the absence of hydrogen, by methods not otherwise provided for
    • C10G31/10—Refining of hydrocarbon oils, in the absence of hydrogen, by methods not otherwise provided for with the aid of centrifugal force
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
    • C10G33/00—Dewatering or demulsification of hydrocarbon oils
    • C10G33/04—Dewatering or demulsification of hydrocarbon oils with chemical means
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
    • C10G33/00—Dewatering or demulsification of hydrocarbon oils
    • C10G33/06—Dewatering or demulsification of hydrocarbon oils with mechanical means, e.g. by filtration
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
    • C10G53/00—Treatment of hydrocarbon oils, in the absence of hydrogen, by two or more refining processes
    • C10G53/02—Treatment of hydrocarbon oils, in the absence of hydrogen, by two or more refining processes plural serial stages only

Definitions

  • the present invention relates to processes for treatment of petroleum/crude sludge, emulsions and slop oil. More particularly, the present invention relates to a process of removal of bound and unbound water from petroleum/crude sludge, emulsions and slop oil comprising of hydrocarbons, bound water, unbound water, dissolved and un-dissolved solids, into different pure salable streams, particularly but not restricted to petroleum industry.
  • Petroleum crude comes out of oil wells invariably with water, dissolved and un-dissolved solids and sulfur bearing compounds containing partly both bound water and unbound water.
  • This petroleum crude is thereafter treated at group collection centers (GCCs, hereinafter) of oil companies wherein firstly the petroleum crude is de-sulfurized and then unbound water are removed along with un-dissolved solids.
  • GCCs do not remove bound water and dissolved solids except in cases where de-emulsifiers are used.
  • desalting of crude leads to additional formation of emulsion with bound water, crude with bound water is sent to oil wells.
  • GCC is specifically required to remove sulfur with most of the un-dissolved solids from the crude and remove entire water to bring down the crude water content below 5000 ppm before sending it to refineries.
  • the process of removal of water mainly involves allowing the crude to settle in a settling tank wherein the top layer, middle layer and bottom layer are formed.
  • the top layer contains pure crude that is sent to refineries for further treatment.
  • the middle layer contains water bearing emulsion that is sent to tank where it is heated subjected to high voltage oscillating electric field and optionally with use of de-emulsifiers where the purpose is to remove maximum water in least time.
  • the bottom layer normally contains oily water with un-dissolved solids which is known as slop oil. Being a pollutant, often the slop oil is sent to abandoned oil wells for storage through pipe lines.
  • Sludge is generally a tightly held viscous emulsion of oil, water and solids wherein the solid content could vary widely. Whenever oil and water is mixed and agitated, sludge gets formed. In refineries, sludge is also formed in the desalting unit where crude is washed with fresh water to remove Alkalis that had ingressed with seawater. Also, sludge gets produced in hydro-crackers, crude storage tanks, slop oil, API separators and the like. Normally 1.6 kgs. of sludge is produced per tonne of crude.
  • Sludge also gets formed, when water in crude is vigorously agitated/sheared by transfer pumps. Being heavier than light oils, it tends to settle at the bottom of ship, load, but gets removed from ship, when crude is pumped out at the refinery.
  • tank sludge which is a solid layer that accumulates with time at ship bottom, and is removed once in 5 years or so.
  • tank sludge typically a 60-M tank disgorges 1,000 MT of material. About 85 to 90% of it constitutes heavy hydrocarbons like paraffin, asphalt, micro-crystalline wax, etc. Often this material is removed using high pressure water jets. Sludge also gets generated in post refinery operations.
  • DG sets 0.5 wt % to 1 wt % sludge gets formed. These DG sets could either be land based or marine. Sludge also gets produced in waste-oil re-conditioning plants. Formation of sludge is a great problem in overall world.
  • M/s. Smith & Loveless Inc. treats refinery sludge with chemicals and aeration.
  • M/s. Lenntech Petrochemical Company from Netherlands uses chemicals, solvent extraction, membranes, filtration, floatation, flocculation, reverse osmosis, etc. to recover oil.
  • M/s. Reverse Oil a Ukrainian-American Joint Venture is desludging “Ukrtatnafta” sludge ponds since 1996, with a plethora of chemicals, merely to minimize its adverse environmental impact.
  • sludge breaking with chemicals/de-emulsifiers doesn't always affect 100% separation.
  • the use of de-emulsifiers is unfit for further use within refineries unless the recovered oil is predominantly free from water.
  • German patent document DE 19936474 to Bereznikov Anatoli provides separation of oil-containing sludges by heating with a solvent and recycling the solvent is effected using a solvent (e.g. toluene) forming a heterogeneous azeotropic mixture with the aqueous component.
  • a solvent e.g. toluene
  • the mixture is steadily mixed to give slurry which is then heated to its boiling point.
  • the saturated vapour is condensed and the aqueous component and the solid residue removed, this being continued to complete water separation by controlling the temperature increase.
  • Spanish patent document ES2047129T3 to Richter Gedeon Vegyeszet discloses dehydration process employing Azeotropic distillation and more particularly it relates to a process for the vigorous dehydration of substances or mixtures, primarily condensation reaction mixtures, (e.g. direct esterification, direct acetal formation, direct ketal formation) using continuous Azeotropic distillation.
  • condensation reaction mixtures e.g. direct esterification, direct acetal formation, direct ketal formation
  • 3,669,847A to Dynamit Nobel Ag discloses process for separating steam-volatile organic solvents from industrial process waste waters wherein Steam-volatile organic solvents are removed from process waste waters by intimately mixing the process waste waters with steam to form an azeotropic steam mixture, withdrawing the Azeotropic steam mixture from the resultant mixture of steam and water, and condensing said Azeotropic steam mixture.
  • CEVA International Inc. & M/s. E & I Technologies, Inc. recover oil by centrifuging sludge.
  • PWS M/s. Petro-Waste Services, Inc.
  • CEVA offers equipment in 2 sizes. One processes 200 tonnes of sludge/day, while the other handles 475 tonnes of sludge a day. Some of these are mobile units. Often when sludge resolution is not possible, refineries incinerate them. Due to high water content, here burning is often supported with supplementary liquid fuels. M/s. W. N. Best makes incineration systems for processing 0.38 to 26.5 tonnes of petroleum sludge/hour. Many modern refineries dump their sludge in Coker Plants, where fuel is partially recovered. Hence they don't generate sludge. Pollution prevention through non-generation is considered to be most profitable. They create what's known as Pet Coke. However, the coke oven plants produce high sulfur contents.
  • Bioremediation is however emerging as major trend.
  • sludge is uniformly mixed with soil, such that its total hydrocarbon content is limited to ⁇ 3 wt. %.
  • Naturally existing bacteria in soil then degrades hydrocarbons into CO2 & H2O over a period of few years. To accelerate this, one increases the supply of air, moisture & nutrients into the soil. To increase nutrients, one supplies nitrogen & phosphorus based fertilizers. A certain density & variety of bacteria also helps. With all these, one tries to achieve a significant reduction of hydrocarbons in soil within about a year. This process is also known as “land farming”, since one works sludge into land with a view to achieve its final disposal through the slow process of bacterial action.
  • Biopiling is a further improvement in this field where homogenous sludge and soil mix are placed over an impermeable base of natural clay, along with wood chips to improve permeability.
  • Perforated pipes are connected to a blower or vacuum pumps to aerate the soil pile.
  • Leachate collection system is also incorporated for uniform addition of water and nutrient.
  • bioremediation technique has certain limitations. Firstly, the bioremediation process leads to entire loss of valuable hydrocarbon which is highly undesired. Secondly, the bioremediation process is highly expense and consumes a lot of time in waste disposal process. Also, the product obtained after remediation fails to convert waste into wealth as the product obtained after bioremediation treatment is of no use.
  • slop oil which is normally an oily water containing solids and salts. This water is treated at Group Collection Centres (GCCs) prior sending it to refineries. Slop oil also gets generated in refineries where the crude is added with fresh water for desaltation and removed using same equipments as that of GCC thereby adding unnecessary cost. Also, lot of hydrocarbon is lost in such process in addition to generation of polluting slop oil.
  • GCCs Group Collection Centres
  • This water being a pollutant is normally sent back for storage wherein the stored corrosive water may leak out in addition to adding cost of transport for discharging the corrosive water in sea water through pipelines.
  • Slop oil also has large implications on environment where it contaminates sea water thereby effecting marine life. Further, slop oil is a major source which has always been neglected although being a valuable source of oil and water both.
  • Slop oil even comes from cleaning of oil contaminated equipments including cleaning of oil carrying ships. Even in industries apart from oil industries, the industries where oil is used as coolant or for lubrication slop oil gets generated.
  • German patent document DE4205885 to Meiken, Bernard entitled “Recovery of water, gasoline, heavy oils, and solids from slop oils or oil emulsions” discloses use of two-phase decanter for centrifuging of slop oil/emulsions wherein Slop oil is heated to 105-135° C. in a heating circuit formed by a heater, column, and pump. The gases and steam are then drawn from the top of the column, and, from the bottom of the column, heated oil slops are taken, cooled, and, in a two-phase decanter separated into a centrifuged clean oil-phase and a solid phase.
  • Russian patent document RU2217476 teaches processes of the oil-bearing slimes refining and extraction hydrocarbons from them for refining of the liquid and pasty oily slimes, in particular of the bottom sediments, resistant oil-water emulsions, intermediate layers containing a fair quantity of mechanical impurities.
  • the method provides for dilution of the oily slimes with petroleum, its heating and separation in the three-phase decanter centrifuge for petroleum, water and a concentrate of mechanical impurities. Residual water is separated from petroleum with the light oil fractions in the distillation column.
  • Chinese patent document CN100582031 to China Nat Petroleum Corp discloses a process for processing and utilizing for oil field oil-containing sewage sludge.
  • the invention relates to the process and utilization method of the oily sludge wherein the horizontal centrifuge via a secondary lift pump is used for dehydration. The dehydrated water enters the coming liquid pipeline of the sewage disposal system after centrifuge operation.
  • centrifuge technique is not without limitations.
  • centrifuges There are generally two types of centrifuges that are used in tandem, namely a decanter and disc stack centrifuge.
  • the disc stack centrifuge has advantages of higher G but it is inefficient when slop oil contains more amount of solids.
  • the decanters enhance density difference but they fail in case of handling of heavy crude/extra heavy crude contaminated water that has oil density equal to water density.
  • Centrifuge enhances buoyancy but reduces residence time due to which it is effective only when the particle size is more and drag is less.
  • surface charge of the oil particles tends to prevent oil particles to coalesce and come together. Further, the centrifuge can handle ultrafine particles only until population density is very large.
  • centrifuge technique substantially fails to work as intended when the slop oil contains either ultrafine oil droplets or highly viscous oil droplets containing solids and bound water therein.
  • filtration technique is also seen in the art for sludge treatment.
  • Canadian patent document CA1202223 to Amsted Industries Incorporated discloses a deep bed type filter containing gravity separator. The bed is agitated and dislodged oil entrapped in filter bed. Where the oil in the water is unusually viscous or has a waxy, tarlike, or sticky consistency, for example, rejuvenation of the filter bed is enhanced by the addition of a small amount of a solvating liquid to the oil-water mixture before filtering.
  • GB1340931 to Beavon D K teaches a treatment method for oil-water mixture containing also oily particulate solids which is treated by passing it through a granular filter medium to remove the particulate solids wherein the filtrate obtained is being water or a mixture of water and oil. The next is to periodically solvate oil from the granular filter media by passing an oil stripping media through the bed in the same direction as the oil-water mixture without affecting the integrity of the filter medium followed by backwashing the filter to remove the now oil-free solids. The oil-water filtrate obtained may then be separated by gravity settling.
  • filtration technique substantially fails to produce oil free water without any chance of total separation of salable quantity of oil when there is large population of ultrafine droplets of sub-micron size. Further, the filtration technique is highly time consuming considering the pore size of the filtration medium. Moreover, regeneration of filtration medium is a highly tedious and time consuming task.
  • coagulants or flocculants are also used to overcome above disclosed disadvantages of centrifuge and/or filtration.
  • these coagulants/flocculants deteriorate or contaminate quality of oil.
  • the addition of coagulants and flocculants is a slow process and time consuming. If the oil droplets are held by water then neither filtration nor centrifuge will work unless the emulsifiers are used. For example, entire fats cannot be removed from milk by filtration or centrifuge because fats are hold by proteins which are emulsifier in this case.
  • An object of the present invention is to remove bound and unbound water from petroleum/crude sludge and emulsions, comprising of hydrocarbons, bound water, unbound water, solids and dissolved salts into different pure salable streams.
  • Another object of the present invention is to provide a process for treatment of sludge that is cost effective and which facilitates recovery of pure oil and water as complete as possible without deteriorating original composition/characteristics thereof.
  • Further object of the present invention is to provide a process for treatment of slop oil to recover usable water from slop oil by an effective and economically viable process.
  • Yet another object of the present invention is to recover usable hydrocarbons from the slop oil by an effective and economically viable process in addition to mitigating the problems of slop oil pollution.
  • a process for treatment of a sludge mixture wherein the sludge mixture includes hydrocarbons with bound water, unbound water, dissolved and un-dissolved solids therein.
  • the process for treatment of the sludge mixture comprises a first step of centrifuging the sludge mixture in a first centrifuge provided if the sludge mixture splits into various components.
  • the first centrifuge being a batch centrifuge forms a viscous hydrocarbon layer, a slop oil layer and a free flowing hydrocarbon layer.
  • the viscous hydrocarbon layer is desalted 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.
  • the vapors of low boiling liquid hydrocarbons are condensed in a first condenser for obtaining low boiling liquid hydrocarbons along with water for use.
  • the crude hydrocarbons coming from a group collection center are desalted in a second desalter for obtaining desalted product crude thereby removing bound water containing hydrocarbon layer that is subsequently mixed with the viscous hydrocarbon layer from the first centrifuge.
  • the free flowing hydrocarbon layer is desalted in a third desalter for entire removal of salts therefrom.
  • the viscous hydrocarbon layer is treated in a homogenizer by adding a first predefined amount of solvent for forming a volatiles free non-viscous homogenized stream therefrom.
  • BTX and Ash tests of the non-viscous homogenized stream are performed 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.
  • the non-viscous homogenized stream is centrifuged in a second centrifuge for separating a bound water dominant hydrocarbon stream, unbound water dominant or water free hydrocarbon stream and the slop oil therefrom.
  • the non-viscous homogenized stream is treated in a hot insulated settling tank for removal of water free solvent along with hydrocarbons therefrom.
  • the unbound water dominant or water free hydrocarbon stream is heated in a first heating vessel thereby optionally adding a predefined amount of free water.
  • the first heating vessel operates at a first predefined temperature range thereby forming a first residual phase and a first vapor phase.
  • the bound water dominant hydrocarbon stream is heated in a second heating vessel at a second temperature range thereby optionally adding a third predefined amount of additional solvent.
  • the second heating vessel forms a second residual phase and a second vapor phase.
  • the first residual phase is centrifuged 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.
  • the second residual phase is treated in the first heating vessel.
  • the first vapor phase and the second vapor phase are condensed through a second condenser for obtaining at least 100% solvent, the bound water in a range of about 99 wt % to 100 wt % and the free water in a range of about 94 wt % to 99 wt %.
  • the solvent is reused in said process.
  • the first centrifuge reduces quantum of the sludge mixture with bound water that requires further processing which reduces cost and time of further processing.
  • 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.
  • the viscous hydrocarbon layer is having at least 42.21 wt. % water typically having 8.61 wt. % Ash with CV of 5,210 kcal/kg.
  • 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.
  • the first desalter, the second desalter and the third desalter retain the quality of hydrocarbons coming from different process streams and hence improve commercial value thereof.
  • the first desalter, the second desalter and the third desalter prevent needless repetition of identical processes done in the group collection center for removal of bound and unbound water from crude again into refineries after desalting of the crude.
  • 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 in downstream of said process and vessels from refinery onwards processes.
  • the first desalter, the second desalter and the third desalter allow the group collection center to dispatch crude without salts and without having to worry about either disposal or processing of crude containing bound water.
  • the first desalter, the second desalter and the third desalter prevent corrosion of pipelines and tankers during transportation.
  • the heat based stripping vessel separates the low volatiles from the viscous hydrocarbon layer for preventing co-distillation thereof along with the solvent during removal of bound water with solvent in downstream of said process. Removal of the bound water from the viscous hydrocarbon layer also allows removal of heavy metal, Ash and salts therefrom which effectively improves commercial value thereof.
  • the BTX and Ash tests help assists in determination of amount of solvent to be added in said process.
  • the solvent reduces viscosity for removal of bound water from topmost layer of the non-viscous homogenized stream on account of viscosity.
  • the solvent help assists in homogenization of the sludge that in turn helps sampling and further helps in accurate determination of water and Ash content.
  • the solvent is added in said process only for viscous portion of the hydrocarbons which substantially reduces overall use of solvent.
  • the solvent is selected from the group of Benzene, Toluene, Xylene and similar Azeotropes of water.
  • the solvent helps removal of the bound water from the top most layer and has least possible thermal damage to the product hydrocarbon stream in said top most layer.
  • the solvent stream and the second centrifuge mutually remove substantial bound water from the viscous hydrocarbon layer at an ambient temperature.
  • the solvent depresses the boiling point of the bound water.
  • the solvent is added in a range of about 1.8 to 100 times the weight of water present in the sludge for removal of entire bound water.
  • 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.
  • the bound water obtained is high quality usable water that requires minimal treatment for being used as a drinking water.
  • the first predefined temperature of the first heating vessel is in a range of about 90° C.-105° C.
  • the second heating vessel is a multi effect evaporator preferably with thermal vapor recompression to avoid thermal cracking of the product hydrocarbon stream.
  • the second heating vessel includes a foam breaker and an entrainment separator adapted to avoid entrainment of hydrocarbons in condensate.
  • the first heating vessel includes a foam breaker and an entrainment separator adapted to avoid entrainment of hydrocarbons in the condensate.
  • the second heating vessel maintains a controlled rate of heating with an optimum ratio of residual solvent to water for entire removal of bound water from the hydrocarbon.
  • the first and second heating vessels are provided with waste heat for reducing cost of energy in said process.
  • the hot centrifuge is a hot settling tank that ensures adequate reduction in viscosity of hydrocarbons thereby allowing settling of free water present therein over a period of time.
  • the hot centrifuge has a temperature in a range of about 80° C. to 94° C.
  • the hot settling tank may be operated under high pressure so that operating temperature can be increased to further reduce the viscosity of hydrocarbon that will facilitate faster removal of free water without leading to boiling of water.
  • a process for pre-treatment of slop oil where the slop oil contains water, solids, salts and hydrocarbon content greater than 10,000 PPM with or without bound water.
  • the process for pre-treatment of slop oil comprises an initial step of feeding the slop oil in a first settling tank for phase separation thereby forming a substantially unbound water-free hydrocarbon layer with or without salts, a water dominant hydrocarbon layer, and a slop oil layer having hydrocarbon content less than 10,000 PPM.
  • the water dominant layer is treated in a second settling tank by adding a predefined amount of alum therein.
  • the second settling tank forms a substantially unbound water-free hydrocarbon layer, a gelatinous oil bearing layer and alum containing slop oil having hydrocarbon content less than 10,000 PPM.
  • the gelatinous oil bearing layer is centrifuged in a third centrifuge by adding a predefined amount of solvent.
  • the third centrifuge forms a solvent layer containing Alum along with solid coated with hydrocarbons.
  • the solvent layer contains Alum that is being added to the first heating vessel in said process.
  • the third centrifuge helps to quickly separate solvent cum hydrocarbon layers and gelatinous oil bearing layer from slop oil.
  • a process for treatment of slop oil wherein the slop oil contains water, solids, salts and limited hydrocarbon content less than 10,000 PPM with or without bound water.
  • the process comprises an initial step of 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.
  • the above slop oil from is treated 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.
  • BTX and Ash tests of the solvent dominant hydrocarbon layer are conducted for bound water followed by a heat treatment thereof in a third heating vessel and a fourth heating vessel.
  • the third vessel has a predefined amount of solvent added therein.
  • the fourth vessel is having a predefined amount of free water added therein.
  • the third heating vessel and fourth heating vessel separate a vapor phase from a liquid phase.
  • the vapor phase is having entire remaining solvent and free water therein.
  • the liquid phase is having hydrocarbons with limited solids, limited salts and alum therein.
  • the liquid phase is centrifuged through a sixth centrifuge that is operating at a predefined temperature for separating a product hydrocarbon layer from a water layer.
  • the water layer is having limited salts, limited solids and alum therein.
  • the water layer is treated through a first reverse osmosis plant for obtaining water for use and a reject stream.
  • the vapor phase is condensed through a third condenser for obtaining water for use and solvent that can be reused in the high speed shear mixer.
  • the water dominant hydrocarbon layer is heated 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.
  • the fifth heating vessel produces a liquid phase that includes remaining water, limited hydrocarbons, salts and solids with a substantially low turbidity.
  • the liquid phase is treated in a settling tank followed by addition of a predefined amount of alum therein.
  • the settling tank forms a water dominant alum layer and a gelatinous oil bearing layer.
  • the water dominant alum layer is filtered in a filtration unit.
  • the filtration unit separates the water dominant alum layer into a filtrate stream and a residual stream.
  • the filtrate stream includes water, alum and salts therein.
  • the residual stream includes wet solids with traces of hydrocarbons, salts and alum.
  • the filtrate stream is treated in a second reverse osmosis plant for recovering usable water therefrom.
  • the filtration unit in accordance with the present invention brings down the turbidity value of the slop oil below 1 NTU. Effectiveness of filtration depends on pore size of the filtrate media and nature of hydrocarbons present in the slop oil.
  • the residual stream is mixed 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.
  • the viscous liquid is agitated in an agitator cum de-oiling unit by adding a predefined solvent followed by treatment thereof through a seventh centrifuge thereby adding water therein.
  • the seventh centrifuge provides a water layer, a cake layer and a solvent layer, the water layer having alum, salts and limited solvent therein.
  • the cake layer is preferably a cake of de-oiled solids with solvent, limited salts and limited alum.
  • the water is treated 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 either for use or for further treatment in said process.
  • the solvent layer is treated in the fourth heating vessel for recovery of solvent.
  • the cake layer is treated in a second hot dryer for recovery of solvent through the condenser. The second hot dryer produces dried de-oiled solids having traces of alum and salts therein.
  • the third heating vessel is a multiple effect evaporator preferably with thermal vapor recompression adapted to avoid thermal cracking of the product hydrocarbon.
  • the third heating vessel has a temperature in a range of about 70° C.-150° C.
  • the fourth heating vessel has a temperature in a range of about 90° C. to 105° C.
  • the fifth heating vessel has a temperature in a range of about 90° C. to 105° C.
  • the sixth centrifuge is a hot centrifuge that has a temperature of about 80° C. to 94° C.
  • the sixth centrifuge is a hot settling tank that has a temperature of about 80° C. to 94° C.
  • the hot settling tank may be operated under high pressure so that operating temperature can be increased to further reduce the viscosity of hydrocarbon that will facilitate faster removal of free water without leading to boiling of water.
  • the sixth heating vessel is an evaporator.
  • the sixth heating vessel has a temperature in a range of about 90° C. to 105° C.
  • the BTX study and Ash study help assists in determination of amount of solvent to be added in said process.
  • the solvent is selected from the group of Benzene, Toluene, Xylene and other azeotropes of water.
  • the first hot dryer has a temperature of about 108° C.
  • the second hot dryer has a temperature of about 200° C.
  • the first reverse osmosis plant removes alum, salts and solids to produce water of usable quality. Addition of alum in the second settling tank neutralizes surface charge which facilitates speedy separation of the hydrocarbons through flocculation and formation of the gelatinous oil bearing layer.
  • the fourth centrifuge is a multi-pass centrifuge that reduces turbidity value of slop oil to a limiting value beyond which centrifuge is unable to produce any further value addition because then size variations of dispersed oil droplets become narrow and population density of dispersed oil droplets also falls with increase in mean free path, residual droplets are electrically charged and density difference is very small.
  • the above lacuna for centrifuge gets magnified when starting turbidity value of the slop oil is very high.
  • the solvent is added through the high shear mixer when centrifuge reaches its limiting value. Addition of solvent enhances the operating range of centrifuge by bringing in large variation in droplet size and also by increasing the population density of droplets along with increasing density difference between oil and water.
  • the centrifuge again reaches a limiting value at that point the residual solvent is boiled out with free water in a temperature range of about 90° C. to 99° C.
  • a process for treatment of a sludge mixture comprising of a centrifuge.
  • the process for treatment using only centrifuge comprises a step of centrifuging the sludge containing hydrocarbons, bound water, salts and solvents in a centrifuge to break the binding between hydrocarbons by increasing residence time of the hydrocarbons in the centrifuge thereby forming three different layers, namely a viscous hydrocarbon layer with bound water, salts and solids, a free flowing hydrocarbons layer with limited salts and solids and a free water with limited solids and salts.
  • the centrifuge repositions the viscous hydrocarbon layer from a back side to a middle side of the centrifuge by slowly increasing revolutions per minute thereof and slowly decreasing an angle between a vertical axis of centrifuge container and a horizontal plane thereof by gradually reducing but not allowing it to become 0°.
  • the sludge mixture has bound water requiring further processing which reduces further processing cost and time.
  • the centrifuge gives a large amount of marketable product hydrocarbons, namely free flowing hydrocarbons.
  • a process for treatment of sludge mixture with combined effect of centrifuge and solvent wherein the sludge mixture contains bound water, salts and solids therein.
  • the process for treatment comprises an initial step of adding of a predefined amount of solvent in the sludge mixture followed by mixing thereof to reduce the viscosity of the sludge mixture.
  • the sludge mixture is centrifuged 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 has an extended residence time for getting less of sludge with bound water therein.
  • the large layer of solvent and hydrocarbon is treated for recovery of solvent by boiling through free water in a temperature range of 90° C. to 99° C. at an atmospheric pressure.
  • the sludge mixture has bound water requiring further processing reduces thereby saving further processing cost and time.
  • the centrifuge gives a large amount of marketable product hydrocarbons, namely free flowing hydrocarbons.
  • FIG. 1 is a process flow diagram showing production and collection of crude at a group collection center
  • FIG. 2 is a process flow diagram showing treatment of a sludge mixture of FIG. 1 prior to removal of bound water therefrom;
  • FIG. 3 is a process flow diagram showing treatment of the sludge mixture of FIG. 2 for removal of bound water therefrom;
  • FIG. 4 is a process flow diagram showing treatment of slop oil with hydrocarbon content above 10,000 PPM;
  • FIG. 5 is a process flow diagram showing treatment of the slop oil with hydrocarbon content equal to or less than 10,000 PPM;
  • FIG. 6 is a continued process flow diagram of FIG. 5 showing treatment of the slop oil with hydrocarbon content equal or below 10,000 PPM;
  • FIG. 7 shows a graphical representation of Benzene at a rate of 2500 PPM when mixed with water using high shear mixer for 1 minute;
  • FIG. 8 shows a graphical representation of Benzene at a rate of 5000 PPM when mixed with water using high shear mixer for 1 minute;
  • FIG. 9 shows a graphical representation of Toluene at a rate of 2500 PPM when mixed with water using high shear mixer for 1 minute;
  • FIG. 10 shows a graphical representation of Toluene at a rate of 5000 PPM when mixed with water using high shear mixer for 1 minute;
  • FIG. 11 shows a graphical representation of Xylene at a rate of 2500 PPM when mixed with water using high shear mixer for 1 minute;
  • FIG. 12 shows a graphical representation of Xylene at a rate of 5000 PPM when mixed with water using high shear mixer for 1 minute;
  • FIG. 13 shows a graphical representation of Coconut Oil at a rate of 2500 PPM when mixed with water using high shear mixer for 1 minute;
  • FIG. 14 shows a graphical representation of Coconut Oil at a rate of 5000 PPM when mixed with water using high shear mixer for 1 minute;
  • FIG. 15 shows a graphical representation of Coconut Oil at a rate of 2500 PPM when mixed with water using high shear mixer for 3 minutes;
  • FIG. 16 shows a graphical representation of Coconut Oil at a rate of 2500 PPM when mixed with water using high shear mixer for 5 minutes;
  • FIG. 17 shows a graphical representation of ONGC Oil at a rate of 2500 PPM when mixed with water using high shear mixer for 1 minute;
  • FIG. 18 shows a graphical representation of ONGC Oil at a rate of 5000 PPM when mixed with water using high shear mixer for 5 minutes;
  • FIG. 19 shows a graphical representation of ONGC Oil at a rate of 2500 PPM when mixed with water using high shear mixer for 3 minutes;
  • FIG. 20 shows a graphical representation of ONGC Oil at a rate of 2500 PPM when mixed with water using high shear mixer for 5 minutes;
  • FIG. 21 shows a graphical representation of Diesel at a rate of 2500 PPM when mixed with water using high shear mixer for 5 minutes.
  • references in the specification to “one embodiment” or “an embodiment” means that a particular feature, structure, characteristic, or function described in connection with the embodiment is included in at least one embodiment of the invention.
  • the appearances of the phrase “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment.
  • the term “Sludge” is defined broadly as a mixture of hydrocarbons, bound and unbound water, dissolved and undissolved solids and naturally occurring emulsifiers.
  • the sludge in accordance with the present invention is a sludge that contains total water content is in a range of 2 wt % to 95 wt %. However, when total water content is in a range of 2 wt % to 61 wt %, the entire water in the hydrocarbons is bound water when emulsifiers are not additionally added. When the water content is above 61% the water is combination of both bound water and unbound water. Sludge is deadly pollutant as it contains heavy metals and getting rid of is an expensive affair. It can pollute ground, water and even air through low volatiles.
  • the term “Slop oil” is defined broadly as a mixture of hydrocarbons, emulsifiers, un-dissolved solids, hydrocarbon coated un-dissolved solids and dissolved solids, bound and unbound water.
  • the slop oil in accordance with the present invention is having hydrocarbon content in a range of 5 ppm-5 lac ppm. These hydrocarbons are not water soluble. Often when oil content extends beyond 10,000 PPM, it will reasonably quickly spilt into 3 layers, a decantable top layer of pure oil with PPM level of water, a significant water bearing oil in the middle where separation rate of pure oil is slow and a residual bottom layer which is slop oil containing less than 10,000 PPM.
  • Brown Water is defined broadly as water that does not come out hydrocarbon inspite centrifuging the sludge at 21893 RCF for at least 10 minutes is bound water.
  • Unbound Water is defined broadly as any water apart from bound water.
  • Dissolved Solids is defined broadly as the solids that are dissolved in the water that comes out with sludge.
  • Un-dissolved Solids is defined broadly as the heavy metals including radioactive metals that come out from oil well along with crude.
  • a process flow chart 100 shows a process undergone by a petroleum crude 102 after being recovered through a plurality of oil wells 101 followed by processing thereof at a group collection center 104 (GCC, hereinafter) as illustrated.
  • the crude 102 preferably contains sulfur, bound water, unbound water, salts and solids. However, gases, if any, are removed from the crude 102 at line 101 A before being sent to GCC 104 .
  • the GCC 104 includes a desulfurization plant 106 that separates out sulfur from crude 102 via line 108 thereby forming a sulfur-free crude stream 110 containing crude with bound water, unbound water, salts and solids.
  • the sulfur-free crude stream 110 is fed to a gravity based settling tank 112 .
  • the gravity based settling tank 112 separates crude into three streams namely an upper crude stream 114 , a middle crude stream 116 and a lower crude stream 118 .
  • the upper crude stream 114 contains crude with salts, limited solids and traces of water that follows line-A.
  • the lower crude stream 118 contains water with salts, solids and limited crude that follows line-B. It is understood here that lower crude stream 118 is slop oil stream having less than 10,000 PPM hydrocarbon content in this one preferred embodiment.
  • the middle crude stream 116 contains crude with salts, bound water, unbound water and solids that is fed to a hot insulated settling tank 120 through line 119 .
  • the hot insulated settling tank 120 operates at an atmospheric pressure and at a temperature at about or less than 95° C.
  • a de-emulsifier 122 is optionally added to the hot insulating settling tank 120 through line 124 .
  • a high voltage oscillating electric field 125 is given to the hot insulating settling tank 120 in this one embodiment.
  • the hot insulated settling tank 120 treats the middle crude stream 116 thereby forming three layers therein, namely a top crude layer 126 , a middle crude layer 128 and bottom, crude layer 130 .
  • the top crude layer 126 contains crude with salts, limited solids and traces of water that follows line-A.
  • the bottom crude layer 130 contains water with salts, solids and limited crude that follows line-B.
  • the bottom crude layer 130 is slop oil having less than 10,000 PPM hydrocarbon content.
  • the middle crude layer 128 is preferably sludge in accordance with the preferred embodiment which contains crude with bound water, salts, limited unbound water and limited solids. Accordingly, the sludge 128 follows line-C in this one preferred embodiment.
  • a process 200 for treatment of the sludge 128 before removal of bound water therefrom is illustrated.
  • the sludge 128 is fed to a first centrifuge 202 through the line-C. Additionally, a plurality of sludges 204 from all other sources with/without salts is added to the first centrifuge 202 along with the sludge 128 .
  • the first centrifuge 202 is a batch type or multi-pass centrifuge, in this one preferred embodiment.
  • the first centrifuge 202 forms three layers, namely a top layer 208 , a middle layer 206 and a bottom layer 210 .
  • the bottom layer 210 preferably contains water with salts, solids and limited crude.
  • the middle layer 206 is preferably a viscous hydrocarbon layer with bound water, limited solids and traces of unbound water with/without salts.
  • the top layer 208 preferably contains free flowing hydrocarbons with or without salts, limited unbound water and limited solids.
  • the bottom crude layer 210 is slop oil having less than 10,000 PPM hydrocarbon content.
  • the middle layer 206 is preferably fed to a first desalter 212 through line 211 if it contains salts. A predefined amount of free water is added to the first desalter 212 in order to obtain an upper stream 213 and a lower stream 214 .
  • the lower stream 214 preferably contains water with salts, solids and limited crude which is mixed with bottom layer 210 in this one embodiment.
  • the upper stream 213 preferably contains desalted viscous hydrocarbons with bound water, limited unbound water and limited solids.
  • the upper stream 213 follows line 213 -A in this one embodiment.
  • the middle layer 206 can be directly fed to a homogenizer 216 through line 215 if the middle layer 206 is without salts and low volatiles. It is understood here that the line 215 may be mixed with the line 213 -A before being fed to the homogenizer 216 .
  • the top layer 208 is preferably fed to a third desalter 218 through line 217 if it contains salts.
  • a predefined amount of free water is added to the third desalter 218 in order to obtain either two or three layers.
  • the third desalter 218 produces an upper layer 220 , a bottom layer 222 and optionally a middle layer 224 if it has a fraction having bound water contained therein.
  • the upper layer 220 is a free flowing salt free hydrocarbon product with limited solids and traces of water.
  • the bottom layer 222 contains water with salts, solids and limited crude that follows line-B. In this one embodiment, the bottom crude layer 222 is slop oil having less than 10,000 PPM hydrocarbon content.
  • the middle layer 224 if formed, is added to the upper stream 213 in this one embodiment.
  • the crude stream 114 containing crude with salts, limited solids and traces of water following line-A is fed to a second desalter 228 .
  • the second desalter 228 preferably forms three layers, namely a top layer 230 , a middle layer 232 and a bottom layer 234 .
  • the bottom layer 234 contains water with salts, solids and limited crude that follows line-B.
  • the bottom crude layer 234 is slop oil having less than 10,000 PPM hydrocarbon content.
  • the top layer 230 is a desalted product crude with traces of solids and water which goes back to, refinery as a product.
  • the middle layer 232 contains desalted viscous hydrocarbons with bound water that is added to the stream 213 and fed to the homogenizer 216 .
  • the homogenizer 216 treats desalted viscous hydrocarbon layer with bound water, limited unbound water and limited solids thereby adding a limited solvent stream 236 in case where the hydrocarbons are highly viscous.
  • the homogenizer 216 advantageously facilitates addition of solvent only after reducing volume of sludge and specifically for viscous hydrocarbon portion thereby drastically reducing overall use of solvent in the process.
  • the solvent is also added to the homogenizer 216 in order to help assist in BTX study being performed during the process.
  • the solvent 236 also helps assists in reducing viscosity for removing bound water on account of viscosity.
  • the solvent 236 is selected from one or more of the following Benzene, Toluene and Xylene.
  • the homogenizer 216 produces a non-viscous homogenized stream 238 that follows line-D as illustrated.
  • the stream 238 preferably contains hydrocarbons that are volatiles free, desalted and non-viscous.
  • the hydrocarbons in the non-viscous homogenized stream 238 preferably contain bound water, limited unbound water and limited solids contained therein.
  • a heat based low volatiles stripping vessel 240 may be employed if the desalted viscous hydrocarbons in the stream 213 contain low boiling volatiles therein.
  • the stream 213 is sent to a heat based low volatiles stripping vessel 240 via line 242 instead of being sent to homogenizer 216 via line 213 -A.
  • the viscous hydrocarbon layer 206 may be directly fed to the heat based low volatiles stripping vessel 240 through line 244 if it is free from salts but contains only low volatiles therein.
  • the heat based low volatiles stripping vessel 240 is adapted in the process 200 to prevent the low volatiles to come out with solvent by separation thereof which would otherwise contaminate the solvent and removal of these hydrocarbons later on would need fractional distillation which would be needlessly a costlier affair. Hence, the heat based low volatiles stripping vessel 240 is adapted in the process to separate the low volatile hydrocarbons.
  • the heat based low volatiles stripping vessel 240 is provided with a waste heat to facilitate heating.
  • the heat based low volatiles stripping vessel 240 forms a vapor phase 246 and a liquid phase 248 .
  • the vapor phase 246 preferably contains vapors of low volatiles, hydrocarbons and water.
  • the liquid phase 248 preferably contains volatiles free, desalted hot hydrocarbons with bound water, limited unbound water and limited solids.
  • the vapor phase 246 is sent to a first condenser 250 for removing heat therefrom followed by processing through a first condensate/phase separator 252 .
  • the condensate/phase separator 252 preferably forms a first layer 254 , a second layer 256 and a third layer 258 .
  • the first layer 254 contains pure water that can be reused in the process or packed for sale.
  • the second layer 256 contains low boiling liquid hydrocarbons that are mixed with a desalted product crude 230 through line 260 .
  • the third layer 258 contains non condensable vapors of hydrocarbons that are flared as a source of heat via line 262 as illustrated.
  • the liquid phase 248 is fed to a cooling vessel 264 wherein the hot hydrocarbons are cooled to a room temperature and added to the homogenizer 216 via line 266 to subsequently produce the product stream 238 which follows line-D as illustrated.
  • the first centrifuge 202 is able to separate sludge wherein one can find a small fraction of viscous hydrocarbons floating on the top carrying about 40-44 wt % bound water and 13% Ash.
  • the free flowing hydrocarbons about 40 wt % are obtained which contains 0.3 wt % to 0.8 wt % Ash and less than 3000 ppm of water.
  • the water that goes out is having turbidity well below 20 NTU. One cannot add this water back to the hydrocarbons and make sludge thereby preventing reconstitution.
  • a process 300 for treatment of the product stream 238 for removal of bound water is illustrated.
  • the product stream 238 (refer FIG. 2 ) is fed to an agitator cum homogenizer 306 through the line-D after performing a BTX study 302 and an ash content study 304 .
  • the BTX study 302 is performed to detect moisture content in the product stream 238 and the ash content study 304 is performed to detect ash content in the product stream 238 .
  • a calculated amount of solvent 308 is added in the agitator cum homogenizer 306 through line 310 . It is understood here that the quantum of solvent added has an impact in the agitator cum homogenizer 308 in order to bring out the water at least temperature from the hydrocarbons.
  • ratio of Xylene to wt. of hydrocarbon/water (whichever is higher) is 5.5.
  • ratio of Toluene to wt. of hydrocarbon/water is 10.0.
  • ratio of Benzene to wt. of hydrocarbon/water is 80.0.
  • the contents in the agitator cum homogenizer 306 are fed to a second centrifuge 312 through line 311 .
  • the contents in the agitator cum homogenizer 306 are fed to a hot insulating tank 312 A that separates out a water free top layer 312 B containing solvent and hydrocarbons.
  • the water free top layer 312 B follows line-J as shown.
  • the second centrifuge 312 splits the contents in three layers, namely a first layer 314 , a second layer 316 and a third layer 318 .
  • the first layer 314 is an unbound water dominant hydrocarbon stream that preferably contains volatiles free desalted hydrocarbons, solvent, limited unbound water and solids contained therein.
  • the second layer 316 is a bound water dominant stream that preferably contains volatile free desalted hydrocarbons with bound water, solvent, limited bound water and solids contained therein.
  • the third layer 318 preferably contains water with solids, limited hydrocarbons and solvent that follows line-B. It is understood here that the contents in the hot insulating tank 312 A may be mixed with the third layer 318 via line 312 C.
  • the third layer 318 is slop oil having less than 10,000 PPM hydrocarbon content.
  • homogenizer 306 one puts hydrocarbons for the treatment with up to 61% bound water wherein the difference in density between water and hydrocarbon is in a region of 0.05 gm/cc and containing bound water which does not come out of the first centrifuge 202 in spite of 21900 RCF for 10 minutes. However, after adding solvent 308 followed by reduction in viscosity in the second centrifuge 312 the entire bound water comes out in subsequent processing. It is understood here that the same hydrocarbon had undergone similar centrifugal action in first centrifuge 202 where viscosity was reduced still the bound water that is recovered here had not come out. This fact of recovery of bound water is a discovery in accordance with the present invention.
  • the first layer 314 is fed to a first heating vessel 320 through line 322 .
  • the first heating vessel 320 operates at an atmospheric pressure and a temperature range of about 90° C. to 105° C., more preferably in a range of about 90° C.-98° C., in this one preferred embodiment.
  • a predefined amount of free water is added to the first heating vessel 320 and waste heat is supplied for heating the first heating vessel at the desired temperature in order to produce a first residual phase 324 and a first vapor phase 326 .
  • free water may perform an additional function of de-salting and de-ashing apart from boiling out entire pure solvent for re-use or sale at temperatures below 100° C.
  • the first vapor phase 326 preferably contains vapors of entire remaining solvent and part of unbound water which is fed to a second condenser 328 where heat is removed from the vapors to form a liquid phase that moves to second condensate phase separator 330 through line 329 .
  • the condensate phase separator 330 separates the liquid phase into a solvent phase 332 and a water phase 334 .
  • the solvent phase 332 is preferably reused in the process.
  • the water phase 334 is pure water having turbidity less than 5 NTU which is either recycled in the process or packed for sale.
  • the first residual phase 324 preferably contains hydrocarbons and remaining unbound water with limited solids that is fed to a hot centrifuge/hot settling tank 336 .
  • the hot centrifuge 336 operates at an atmospheric pressure and preferably at an inlet temperature less than or equal to 95° C. and more preferably at the inlet temperature of 92° C.-93° C.
  • the hot centrifuge 336 preferably separates the liquid stream 324 into two layers, namely a top layer 338 and a bottom layer 340 .
  • the top layer 338 preferably contains volatiles free desalted hydrocarbon product with traces of water/solids having water content less than 5000 ppm.
  • the bottom layer 340 entirely contains unbound water with solids and traces of hydrocarbons.
  • the bottom layer 340 is mixed with water phase 334 via line 341 if it has turbidity less than 5 NTU.
  • the bottom layer 340 is fed to an alum based settling tank 342 via line 343 if the turbidity is greater than 5 NTU.
  • the alum based settling tank treats the water to bring the turbidity below 5 NTU followed mixing thereof with water phase 334 via line 344 .
  • Alum based settling tank 342 may be a filtration unit or a reverse osmosis plant in other alternative embodiments of the present invention.
  • the second layer 316 is fed to a second heating vessel 346 through line 348 that operates at an atmospheric pressure and preferably in a temperature ranges of about 70° C.-150° C. wherein waste heat is applied for heating purpose.
  • the second heating vessel 346 may be a multi effect evaporator with thermal vapor recompression alternative embodiment of the present invention.
  • the second heating vessel 346 may be a foam breaker and entrainment suppressor in yet another embodiment of the present invention.
  • a predefined of solvent may be added to the second layer 316 if required.
  • the second heating vessel 346 forms a second vapor phase 350 and a second residual phase 352 .
  • the second vapor phase 350 contains vapors of solvent with entire bound water and unbound water which is fed and processed through the second condenser 328 as per the treatment process of vapor phase 326 as stated above.
  • the second residual phase 352 is added the first heating vessel 320 and processed therethrough as illustrated.
  • the first centrifuge 202 advantageously allows rapid separation of the sludge into value added layers at ambient temperature wherein typical CV of incoming sludge is about 6,044 kcal/kg with water content about 40 wt. % and ash content about 3.68 wt. %.
  • the first centrifuge substantially reduces the mass of the sludge to be handled subsequently by more than 3 times followed by separating in-coming hydrocarbons into two fractions that commands different market price and in all probability different subsequent treatment.
  • the first centrifuge 202 operates for 10 minutes at relative centrifugal force (RCF, hereinafter) of 4,500 (which requires cycle time of 30 mins.) to produce about 41 wt.
  • the first centrifuge 202 enhances force of buoyancy over extended time by gradually increasing the RPM and also by having centrifuge bottles held onto rotor through a pivot.
  • the first centrifuge 202 provides an extended residence time with enhanced force of buoyancy that allows building up of an adequately large Kinetic Energy differential between droplets of separating liquids, which then, on exceeding a threshold value, provides the energy needed to break the bonds that were holding these droplets together. Breaking of bonds was necessary but not adequate. Subsequently, these different materials are carried as entirely as possible through one another and collect them into distinct, single component layers 206 , 208 and 210 .
  • the enhanced or increased residence time or centrifugal force squeezes out more water and to a small extent even oil from viscous layer 213 and by doing so makes it even further viscous and hence reaching a limiting point beyond which it did not make sense to try any further.
  • the Combination of progressively increasing RPM and of pivots holding centrifuge bottles probably had a couple of additional impacts. Initially, a less RPM which is low centrifugal force limits accumulation of viscous hydrocarbons that helps in collection of the viscous hydrocarbons as lumps without flattening thereof as cakes. Further, a low RPM wherein the force of weight is larger than centrifugal force helps collection of the viscous hydrocarbons at the bottom-most space within bottles thereby leaving behind ample free space at top.
  • the three. desalters 212 , 218 , 228 facilitate de-salting of crude prior to removing bound water and also prior to dispatching it to refineries. This has a special importance in accordance with the present invention.
  • the process 200 includes placement of desalters 212 , 218 and 228 allow crude de-salting at the specific location within the proposed process which is different from its current location.
  • the desalters 212 , 218 and 228 prevent needless, expensive, time-cum-capital consuming repetition of crude de-Watering at refineries, after first carrying out exactly similar process earlier at GCCs.
  • the desalters 212 , 218 and 228 enhance product quality and reduce expense on paid energy, by preventing ingression of water into crude stream at refineries.
  • the desalters 212 , 218 and 228 at our disclosed location of the process 200 facilitates mitigation of the problem of bound water that gets into Crude while de-salting, without having the advantage of distillation column.
  • the desalters 212 , 218 and 228 prevent mixing of hydrocarbons having bound water with hydrocarbons having unbound water and the product hydrocarbon stream in comparison to mere de-salting. This also allows preventing mixing of viscous hydrocarbons with free flowing hydrocarbons.
  • the second desalter 228 has unique ability to dispatch de-salted hydrocarbons to refineries without loading them with bound water.
  • the heat based low volatiles stripping vessel 240 facilitate stripping in case of hydrocarbons coming in with bound water and low-boiling volatiles.
  • the stripping vessel 240 strip these low volatiles and separate them by heating prior to removal of bound water using solvents and even prior to addition of solvent itself in the process 200 thereby preventing the low boiling volatiles to distill out with the solvent during removal of bound water with solvent in downstream of the process 200 wherein depending on the solvent used the final temperature could rise at least as high as 140° C.
  • the stripping vessel 240 also prevents the low volatiles to enter in subsequent purification of the solvent which would otherwise become a far more expensive & elaborate a process.
  • the heat based low volatiles stripping vessel 240 prevents low boiling volatiles to distill out with the solvent during removal of bound water subsequently with the use of solvent in the homogenizer 306 and the second centrifuge 312 followed by exposure to temperature of at least as high as 98° C. in the first heating vessel 320 .
  • the heat based stripping vessel facilitates recovery of the low boiling hydrocarbons that can be recycled back to the desalted product crude 230 which apart from conservation and economical advantages help to deliver back the hydrocarbons in as original form as possible. If a fraction of low volatiles becomes non-condensable stream 258 due to thermal cracking then that fraction would be either flared or combusted to provide an additional source of heat.
  • addition of solvent before the second centrifuge 312 is more important instead of addition of solvent, before the first centrifuge 202 .
  • This is partly because one would end up consuming more solvent in such case as it will get needlessly mixed also with the free flowing hydrocarbons. This may lead to an additional cost and process for subsequent removal of the solvent from free flowing hydrocarbons.
  • the removed solvents would get contaminated with low boiling hydrocarbons in such case. Also, one would end up mixing low valued viscous hydrocarbons with higher valued free flowing hydrocarbons in such case.
  • the second centrifuge 312 treats the solvent bearing sludge after removing the clear water with turbidity values from below 20 NTU in certain cases.
  • the second centrifuge 312 removes entire remaining bound water from the sludge stream fed thereto such as Furnace Oil Sludge, ONGC Viscous Hydrocarbons and the like.
  • the second centrifuge 312 does not remove the entire bound water from the sludge where a part of hydrocarbons holds onto bound water on account of emulsifier. Apart from removing bound water, the second centrifuge also helps in reducing ash in hydrocarbons.
  • the process 300 combines the enhanced force of buoyancy due to increased acceleration due to gravity and additionally a significant decrease in viscosity of the sludge by using the solvent, like Xylene, that is in proportion of two times the weight of sludge itself at ambient temperatures and over an extended period of time thereby affecting complete separation of bound water from viscous hydrocarbons which is hitherto not possible either by singly using even 4.87 times more powerful a centrifuge over same time alone or by singly using the same solvent in similar proportion even at twice the ambient temperature Over 72 hours as against 10 minutes.
  • the solvent like Xylene
  • the slop oil stream 402 has hydrocarbon content greater than 10,000 PPM.
  • the slop oil feed stream 402 preferably contains water with salts, solids and limited hydrocarbons with or without bound water.
  • the slop oil feed stream 402 is sent to a first settling tank or a phase separation column 404 wherein preferably three layers are formed, namely a top layer 406 , a middle layer 408 and a bottom layer 410 .
  • the top layer 406 preferably contains free flowing hydrocarbons with or without salt along with traces of water and solids.
  • the middle layer 408 preferably contains hydrocarbons with large amounts of water with or without salts and solids.
  • the bottom layer 410 preferably contains water with salts, solids, limited hydrocarbons which follows line-B. In this one alternative embodiment, the bottom layer 410 is slop oil having less than 10,000 PPM hydrocarbon content.
  • the top layer 406 is directly stored as a product storage tank 412 through line 411 if it does not contain any traces of salts therein. Alternatively, the top layer 406 may be optionally fed to third desalter 218 (refer FIG. 2 ) via line F if it contains salts therein.
  • the middle layer 408 is fed to a second settling tank 414 followed by adding a predefined amount of alum.
  • the second settling tank 414 forms a first layer 416 , a second layer 418 and a third layer 420 .
  • the first layer 416 preferably contains free flowing hydrocarbons with or without salts and traces of water and solids which is mixed with the top layer 406 in this one embodiment.
  • the second layer 418 mainly contains alum with water having salts, solids, limited hydrocarbons.
  • the second layer 418 is mixed with the bottom layer 410 to follow line-B as illustrated.
  • the third layer 420 is a gelatinous oil bearing layer containing hydrocarbons, alum, salts, solids and water contained therein.
  • the third layer 420 follows line-H. It is understood here that addition of alum in the second settling tank 414 facilitates speedy separation of the hydrocarbon through coagulation and formation of the gelatinous oil bearing layer.
  • the first settling tank 404 may occasionally produce a fraction 422 which may contain viscous hydrocarbons with or without salts/solids/bound water.
  • the fraction 422 may be optionally fed to a first desalter 212 via line-I if it contains salts and bound water both.
  • the fraction 422 may be optionally fed to second desalter 228 by mixing with line-A if it contains salts without any bound water therein.
  • the fraction 422 may be optionally mixed with an upper stream 213 via line-E if it contains only bound water without any salts therein.
  • the fraction 422 may be optionally sent to a third centrifuge 424 via line 423 if it contains only solids without any salts and bound water therein.
  • a predefined amount of solvent is added to the third centrifuge 424 in order to separate the fraction 422 into two layers, namely a top layer 426 and a bottom layer 428 .
  • the third centrifuge 424 reduces drag, surface charge on the particles of hydrocarbon thereby reducing mean free path and allowing coalescence of the particles at ambient temperature.
  • the top layer 426 preferably contains hydrocarbons and solvent with traces of solids which is sent to the first heating vessel 320 via line-J.
  • the bottom layer 428 preferably contains solids that are coated with hydrocarbons which follows line-K in this one embodiment. However, the bottom layer 422 may be directly stored as a product 430 via line 429 if it is free from salts, solids and bound water.
  • the slop oil stream 502 preferably has a high turbidity and hydrocarbon content less than 10,000 PPM.
  • the slop oil stream 502 preferably contains water with salts, solids and limited hydrocarbons with or without bound water.
  • the slop oil feed stream 502 is fed to a fourth centrifuge 504 to reduce turbidity and obtain a stream 506 having low turbidity.
  • the fourth centrifuge 504 is a multipass centrifuge that works on its own as long as population density of ultrafine particles of hydrocarbons is high because then mean free path is low.
  • ultrafine particles can be removed only after they coalesce and for coalescing there has to be relative movement between particles. This comes only due to relative particle size distribution. This distribution is very narrow in the zone of high density of small particles. It is understood here that the multipass centrifuge 504 must begin with fresh slop oil. Also, it is understood that the gap between slop oil generation and operation of centrifuge 504 should be as minimum as possible. Further, it is understood that the fourth centrifuge 504 uses the relative motion brought by high G till such time that mean free path between the hydrocarbon particles is increased beyond maximum capacity thereof.
  • the stream 506 having low turbidity is fed to a high speed shear mixer 508 wherein a predefined amount of solvent is added via line 510 thereby forming a mixture 512 that is fed to a fifth centrifuge 514 .
  • Addition of solvent followed by high shear mixing in a range of about 8000-10000 RPM, allows formation of the adequate size solvent particles, preferably in a range of about 0.5 to 0.8 micron size whose population density increases by a substantial amount. It is understood that for adequate disintegration of solvent there is an optimum mixing time that is about 1 min. Further increase in time may result in increase in particle size and fall in turbidity.
  • the right particle size of solvent preferably removes almost similar size of ultra fine oil particles.
  • coalescence speed increases which prove to be a rate controlling step in accordance with the present invention wherein effect of coalescence extends in the working range of the fifth centrifuge 514 .
  • the centrifuge 514 starts working due to high population density and continues till the population density falls down to an earlier level. This effectively allows the oil particles to completely go out.
  • addition of solvent facilitates coalescence that enhances the efficiency of the centrifuge 514 by having enhanced sweeping effect wherein a limiting factor for centrifuge 514 about population density of ultra fine droplets is reached with solvent droplets instead of oil droplets.
  • Addition of solvent in the high speed shear mixer 508 enhances population density within the slop oil that makes the fifth centrifuge 514 to efficiently allow the solvent to facilitate coagulation thereby moving the hydrocarbon particles to move from bottom and separate with a swiping impact. Addition of solvent in large amount in the high speed shear mixer 508 allows replacement of hydrocarbon droplet with solvent droplet for replacing oil with solvent therein.
  • the fifth centrifuge 514 preferably forms two layers, namely a top layer 516 and a bottom layer 518 .
  • the top layer 516 is a solvent dominant hydrocarbon layer that preferably contains a top layer comprising solvent, hydrocarbons with or without bound water, limited free water, limited salts and limited solids.
  • the bottom layer 518 is a water dominant hydrocarbon layer that preferably contains water, limited solvent, limited hydrocarbons, salts, solids with very high turbidity value.
  • the top layer 516 is subjected to a BTX study 520 to know water and ash content for deciding requirement of solvent, if needed.
  • the top layer 516 is added to a third heating vessel 522 via line 524 if the top layer 516 contains hydrocarbons having bound water contained therein.
  • the top layer 516 is added to a fourth heating vessel 526 through line 528 if the top layer 516 contains hydrocarbons having no bound water contained therein.
  • the third heating vessel 522 may be a multi effect evaporator with thermal vapor recompression, foam breaker and entrainment suppressor in other alternative embodiments of the present invention.
  • the third heating vessel 522 preferably operates at an atmospheric pressure and in a temperature range of about 70° C.-150° C.
  • a predefined amount of additional solvent may be added to the third heating vessel 522 based on the BTX study 520 .
  • a predefined amount of waste heat is applied to the third heating vessel for increasing the temperature of the third heating vessel 522 and forming two phases, namely a vapor phase 530 and a liquid phase 532 .
  • the liquid phase 532 preferably contains hydrocarbons, remaining solvent, limited solids and limited salts therein.
  • the vapor phase 530 contains vapors having a part of solvent, entire bound water and free water therein.
  • the vapor phase 530 is fed to a condenser 536 through line 538 .
  • the condenser 536 removes heat from the vapor phase 530 followed by processing through a condensate/phase separator 540 .
  • the condensate/phase separator 540 preferably forms a first layer 542 and a second layer 544 .
  • the first layer 542 contains pure water that can be reused in the process or packed for sale.
  • the second layer 544 contains solvent that is reused in the process by mixing with the solvent line 510 .
  • the liquid phase 532 is free from bound water which is subsequently added to the fourth heating vessel 526 through line 534 .
  • the fourth heating vessel 526 operates at an atmospheric pressure and in a temperature range of about 90° C. to 105° C. A predefined amount of a solvent stream-G (refer FIG. 6 ) may be added to the fourth heating vessel 526 as illustrated.
  • the heating vessel 526 produces a vapor phase 546 and a liquid phase 548 .
  • the vapor phase 546 contains entire remaining solvent and a part of free water.
  • the liquid phase 548 contains hydrocarbons, remaining free water, limited solids, limited salts and alum.
  • the vapor phase 546 is added to the condenser 536 via line 550 .
  • the liquid phase 548 is fed to a sixth centrifuge 552 .
  • the sixth centrifuge 552 is a hot centrifuge or hot settling tank in this one embodiment that operates at an atmospheric pressure and at a temperature equal to or less than 95° C.
  • the sixth centrifuge 552 preferably produces two layers, namely a top layer 554 and a bottom layer 556 .
  • the top layer 554 is a hydrocarbon product having traces of water, salts and solids therein.
  • the top layer 554 is stored or packed for sale.
  • the bottom layer 556 contains water, limited salts, limited solids and alum.
  • the bottom layer 556 is processed through a RO plant 558 to obtain a pure water stream 560 and a reject stream 562 .
  • the pure water stream 560 is mixed with the first layer 542 .
  • the reject stream 562 follows line-H in this one embodiment.
  • the bottom layer 518 is fed to a fifth heating vessel 564 that operates at an atmospheric pressure and in a temperature range of about 90° C. to 105° C.
  • the fifth heating vessel 564 is supplied with waste heat to achieve the desired temperature range.
  • the fifth heating vessel 564 produces a vapor phase 566 and a liquid phase 568 .
  • the vapor phase 566 preferably contains vapors of solvent and part of water that is further processed through the condenser 536 as illustrated.
  • the liquid phase 568 preferably contains remaining water, limited hydrocarbons, salts and solids.
  • the liquid phase 568 has substantially low turbidity which follows line-E as illustrated.
  • the liquid phase 568 following line-E is fed to a third settling tank 602 wherein a predefined amount of alum stream 604 is added.
  • the alum stream 604 is preferably added to reduce the turbidity of the liquid phase 568 and bring it down below 2.0 NTU.
  • the third settling tank 602 may be optionally provided with heat to facilitate alum treatment in hot condition. Addition of Alum under heated condition at a temperature in a range of about 80° C. to 90° C. for at least four hours may reduce the turbidity of the slop oil by at least 90%.
  • the settling tank 602 preferably forms two layers, namely a top layer 606 and a bottom layer 608 .
  • the top layer 606 is a water dominant alum layer that preferably contains water, alum, solids, salts and traces of hydrocarbons contained therein.
  • the bottom layer 608 is preferably a gelatinous oil bearing layer containing hydrocarbons, alum, water, solids and salts therein.
  • the top layer 606 is sent to a filtration unit 610 that splits the top layer 606 into a filtrate stream 612 and a residual stream 614 .
  • the residual stream 614 preferably contains solids with traces of hydrocarbons, salts and alum.
  • the residual stream 614 is mixed with the bottom layer 608 through line 616 .
  • the filtrate stream 612 preferably contains water, alum and salts.
  • the filtrate stream 612 is sent to a RO plant 618 through line 617 for obtaining a pure water stream 620 if total dissolved solids (TDS, hereinafter) of the filtrate stream 612 is high else directly stored or packed for sale via stream 622 if the TDS is low.
  • TDS total dissolved solids
  • addition of alum in third settling tank 602 improves rate of filtration in the filtration unit 610 thereby substantially reducing turbidity below 2 NTU.
  • the bottom layer 608 is mixed with the third layer 420 (refer FIG. 4 ) following line-H and sent to a first hot dryer 624 .
  • the first hot dryer 624 preferably operates at an atmospheric pressure and a temperature of about 108° C.
  • the viscous liquid stream 628 is fed to an agitator/de-oiling unit 630 .
  • a predefined amount of solvent stream 631 is added to the agitator/de-oiling unit 630 along with the bottom layer 428 (refer FIG. 4 ) following line-K and containing solids that are coated with hydrocarbons.
  • the agitator/de-oiling unit 630 produces free flowing liquid stream 632 that preferably contains solvent with hydrocarbons, alum, salts and de-oiled solids.
  • the free flowing liquid stream 632 is sent to a seventh centrifuge 634 through line 633 .
  • the seventh centrifuge 634 may be phase separator in other alternative embodiments of the present invention.
  • the seventh centrifuge 634 preferably produces three layers, namely a first layer 636 , a second layer 638 and a third layer 640 .
  • the first layer 636 preferably contains solvent and hydrocarbons which is added to the heating vessel 526 (as shown in FIG. 5 ) through line-G.
  • the second layer 638 is a water dominant alum layer that preferably contains water with alum and salts along with limited solvent.
  • the second layer 638 is fed to a sixth heating vessel 642 which operates at an atmospheric pressure and in a temperature range of about 90° C.
  • the sixth heating vessel 642 produces two phases namely, a vapor phase 643 and a liquid phase 644 .
  • the liquid phase 644 preferably contains water, alum and salts contained therein.
  • the liquid phase 644 is recycled to the RO plant 618 via recycle line 646 .
  • the vapor phase 643 preferably contains vapors of solvent and water.
  • the vapor phase 643 is sent to a condenser 648 for removing heat followed by processing through a condensate/phase separator 650 .
  • the condensate/phase separator 650 preferably forms a first layer 652 and a second layer 654 .
  • the first layer 652 contains pure water that can be reused in the process or packed for sale.
  • the second layer 654 contains solvent that can be reused in the process.
  • the third layer 640 preferably contains cake of wet de-oiled solids with solvent, limited salts and limited alum.
  • the third layer 640 is sent to a second hot drier 656 that operates at an atmospheric pressure and temperature of about 200° C. A predefined amount of waste heat is applied to the dryer 656 to achieve desired temperature.
  • the second hot dryer 656 treats the third layer 640 thereby removing a vapor stream 658 thereby forming a residual stream 660 .
  • the vapor stream 658 preferably contains vapors of solvent and water contained therein.
  • the residual stream 660 preferably contains dried de-oiled solids with traces of alum and salts.
  • the vapor stream 658 is mixed with the vapor phase 643 and further treated through the condenser 648 as illustrated.
  • the processes 400 and 500 advantageously convert pollutants into valuable product streams thereby mitigating problems of environmental pollution and damage to environment.
  • the processes 400 and 500 facilitate best possible recovery of oil and valuable water wherein the water can be used as a drinking water for commercial use at a cost less than the cost of storage of sludge/slop oil.
  • the processes 400 and 500 facilitate use of chemicals for recovery of oils such that the chemicals used are totally recycled and reused in the process.
  • the process of the present invention runs at almost nil energy cost by making use of waste heat in overall process.
  • a predefined amount of in-house Sludge was prepared with water using Viscous/Non-Viscous Hydrocarbons in order to understand sludges and also for subsequent removal of entire Bound Water from therein. Accordingly, weighed amounts of Water, Hydrocarbons and Sodium Lauryl Sulphate as emulsifier, if any, are mixed and then stirred at 10,000 rpm using a high shear Mixer, for 1 minute at a time and for 5 times, while ensuring that temperature of mixed material never exceeded 58° C. After every 1 minute of mixing the material was cooled to near ambient temperature.
  • the sludge with bound water mean from wherein no free water visibly emerges out even on batch centrifuging it at RCF of 21,893 with residence time of 10 minutes at peak RCF.
  • the sludges were made without using external emulsifier like Sodium Lauryl Sulphate (SLS) with viscous Furnace Oil but not with free flowing diesel. It, was observed that, drag on account of viscosity was an important reason for hydrocarbons to tightly hold onto fine droplets of water. It was observed that for diesel, use of Sodium Lauryl Sulphate was necessary. Even then, as can be seen from Table #3, only 5.96 wt. % of total water present could be bound to diesel and 82.64 wt.
  • SLS Sodium Lauryl Sulphate
  • % water of the sludge exceeded certain threshold value, which lies between the values of 61 to 70, then even without SLS, if a Furnace Oil Sludge was centrifuged for 10 minutes at a peak RCF of 21,893 it was found to be divided into sludge with bound water and slop oil. It was observed that if the sludge was having 70 wt. % water and nil SLS, then it was found to be divided such that 53 wt. % of the sludge was containing 44 wt. % water and the entire water was bound water. The remaining material was found to be the slop oil. Alternatively, it was observed that if furnace Oil containing 96 wt.
  • the sludge was found to be divided such that only 6 wt. % of it forming the sludge with 40 wt. % water, the entire water being bound water, and the remaining material mostly as slop oil. It was further observed that beyond 70 wt. % water, with increasing water content, there was less yield of sludge with bound water in it. However, it was observed that the quantum of bound water inside the sludge does not vary much. Moreover, it was observed that for the less yield of sludge more slop oil was obtained.
  • centrifuging with diesel sludge for 13 minutes at RCF of 21,893 adds value only when the sludge was having emulsifier like SLS in it. This was possible only when the water was bound to the diesel. However, without SLS, water was found to be separated from the diesel without any sludge formation. But once SLS is present, the centrifuging was able to concentrate 87 wt. % diesel into the sludge with just 6.44 wt. % water thereby nearly doubling the energy density within the sludge in no time up to a value of 10,160 kcal/kg which was found to be 92% of energy density of pure diesel.
  • centrifuge enhances acceleration due to gravity by enormously speeding up the naturally occurring separation of two different immiscible liquids due to their density difference. It was observed that the centrifuge was helping when mean free path between tiny droplets of a particular liquid is small followed by consolidating them into much larger droplets with reduced drag, which then helped them move even faster.
  • Example-1 it was observed that on addition of external emulsifiers like Sodium Lauryl Sulphate to furnace oil based sludges containing up to 61 wt. % water with respect to the total water therein, the amount of water held by Furnace Oil as bound water, dropped down from 100% to a much lower level.
  • external emulsifiers like Sodium Lauryl Sulphate
  • Example-3 the furnace oil sludge with 47.52 wt. % water and 2.51 wt. % SLS in it, centrifuging for 10 minutes at 21,893 RCF a viscous sludge was retrieved containing 20.47 wt. % bound water and 3.74 wt. % SLS therein. The obtained viscous sludge with 20.47 wt. % bound water alone was taken for the treatment.
  • Example-2 it was observed that on batch centrifuging of incoming ONGC Lagoon Sludge for 10 minutes at 21,893 RCF or even at 4,500 RCF, the sludge got separated into 3 different layers and middle layer was a viscous sludge with 30 wt. % bound water therein.
  • RCF was just 4,500, the middle layer had 42.21 wt. % total water in it, of which only 72 wt. % was bound water.
  • the middle layer after centrifuging in-coming ONGC sludge for 10 minutes at 4,500 RCF produced 42.21 wt. % total water in it.
  • the temperature had two impacts on the mixture. Firstly, apart from further reducing its viscosity, it enhanced the rate of evaporation of water from the top-most layer. Again, the latter had two implications. Firstly, it helped to reduce water in the top-most layer. Secondly, it enhanced the rate of condensation. Part of our settling vessel projected out above the water level in water bath. Hence, its top portion was relatively cooler, allowing rapid condensation. With that, droplets of condensed water rapidly trickled back into the top-most layer. That in turn explained why we had more water in the top-most layer as observed from Tables 3.5, 3.7 and 3.10.
  • top-most layer consisted of just 6.12 wt. % of total mixture as against 9.07 wt. % in Table 3.5 where more xylene was used.
  • the third layer was obtained only in case of ONGC Sludge containing clear water.
  • the Top-most layer was invariably water free. It was containing bulk of solvent added and also large amounts of hydrocarbons released from sludge.
  • the middle layer in cases where three layers were obtained, was consisting of hydrocarbons and water. Subsequently, the middle layer was evaluated. On centrifuging it for 10 minutes at 21,893 RCF we got sludge with bound Water, albeit much smaller in quantity, a free flowing layer of solvent plus some dissolved hydrocarbons and slightly coloured slop oil. The sludge thus obtained was then evaluated for bound water using BTX and calorific value using Bomb calorimeter.
  • Toluene was observed to remove 85 wt % hydrocarbons present in sludge along with 34 wt. % of water as against Xylene removing 86 wt. % hydrocarbons along with 87 wt. % hydrocarbons and 26 wt. % water present in sludge. Toluene was found to extract water from the sludge in a relatively better manner while Xylene seems to extract hydrocarbons a little better manner in comparison to Toluene.
  • a condenser with chilled water supply was attached to the RB flask with supply of chilled water at 6° C. wherein the vapours of solvent and water were condensed.
  • a Stop Cork at bottom of the receiver was attached to periodically collect condensate and individually weigh the immiscible constituents after first separating them in a separating flask. The temperature of material at near bottom in the RB Flask was continuously recorded using a digital thermometer.
  • Ratio of Solvent to Furnace Oil 2.00 4.00 3.00 6 Observed Boiling Temperature Range at 86.7-98.31 97.28-98.5 96.89-97.58 933 mbar (° C.) 7 Initial Wt. Ratio of Solvent to Water 558.63 4.85 2.07 Collected 8 Final Wt. Ratio of Solvent to Water 0.03 0.08 0.05 Collected 9 Average Wt. Ratio of Solvent to Water 2.26 2.38 1.05 Collected 10 Total Wt. of Water Collected (g) 136.28 252.31 489.69 11 Total Wt. of Solvent Collected (g) 307.89 602.66 464.66 12 Rate of Solvent Collection (g/min) 2.81 2.96 1.76 13 Wt.
  • the temperature range was observed to be higher. It was in a range of about 96.33° C. to 136.28° C. This was because boiling point of pure xylene was higher than that of toluene as can be seen from Table 5.1. Interestingly, it was observed that the end boiling point rose close to that of the boiling point of pure solvent. This was presumably because towards the end, with depletion of bound water, the left over material in the RB flask became similar to the starting material as per Table 6.1. Here too the weight ratio of egressing solvent to water was found to be 1.92 which was lower than that 2.08 as indicated in Table 5.2.
  • boiling point range was found to vary from 72.11° C. to 79.54° C. It was observed that weight ratio of egressing benzene to water for boiling out pure water was 82.34 on an average, which was however more than 61.97 as seen in Table 5.2. This showed here that the water was indeed bound and not free. Therefore, a lot more benzene was required as having weakest ability to remove free water.
  • Furnace Oil Sludges with 50 wt. % Bound Water in it predefined proportions of sludge and solvent by weight were taken in the RB flask of Dean and Stark Apparatus and followed by continuous heating thereof in the mantle heater while continuously monitoring the temperature of material in RB Flask with digital thermometer.
  • the vapours of bound water and solvent were collected in the receiver after condensing them with circulating cold water 5° C. to 6° C. in the insulated condenser.
  • the condensates were out and collected in separating flask using the stop cork at the bottom of the receiver. After phase separation, water and solvent collected were individually weighed each time.
  • furnace oil remained free flowing with very small viscosity till the end.
  • boiling point was not significantly raised till the end by presence of soluble furnace oil with large fraction of residual solvent.
  • the left over weight ratio of solvent to oil was observed to be Minimum of 3.59, 3.09 and 2.98 for Xylene, Toluene and Benzene respectively for removing entire bound water from less viscous Oil.
  • initial wt. ratio of solvent to water/oil are 5.5, 10.0 and 80.0 for Xylene, Toluene and Benzene respectively and follow optimally controlled rate of heating.
  • % bound water was added with twice if its weight of solvent like xylene and then centrifuged for 10 minutes at 21,893 RCF. Most furnace oil in sludge was moved out with solvent leaving behind 14.5 wt. % of initial sludge cum solvent as a stable viscous sludge containing 15 wt. % furnace oil with 85 wt. % bound water in that. This sludge was taken for Test 4 in Table 9.1B and then removed bound water from therein.
  • Rate of water removal was distinctly low when water content in sludge is 15 wt. % or lower. Rate of bound water removal was inversely proportional to binding strength of water to furnace oil. This strength was higher when total water content was lower.
  • boiling point itself starts from 121° C. when water present in furnace oil sludge was only 2.15 wt. % whereas for all other cases is starts from 95° C. or 96° C.
  • 14.79 times of xylene egresses out when water present was 2.15 wt. % per unit mass of water removed. This high value might possibly be due to enormous quantity of Xylene being present. Normally, this weight ratio was observed to be varying from 3.3 to 1.92.
  • Xylene was added to furnace oil sludges with 50 wt. % Bound Water, in 4 weight ratios, i.e. 1.85, 2.50, 3.50 and 5.50 with respect to water present in Sludge. And then for each ratio the heating rate was varied. It was observed that impact of varying heating rate was marginal except for weight ratios 1.85, 3.50 and 5.50. It was observed that medium rate of heating was necessary for weight ratio of 1.85 where water removal rate was 0.48 g/min or condensate removal rate was 1.35 g/min. It was observed that best results in terms of low residual moisture were obtained in left over material with least rise in temperature.
  • the vapors of water and solvent that boiled out were condensed in an insulated condenser where water was circulated at 5° C. to 6° C.
  • the condensates were collected in a receiver thereby using a stop cork at bottom of the receiver to periodically drain out condensate in separating flask while noting the time elapsed. After immediate phase separation the solvent and water collected were individually weighed. At the end material left in RB Flask was weighed and mass balance thereof was performed.
  • Ratio of Solvent to Furnace Oil 3.00 3.00 3.00 3.00 6 Observed Boiling Temperature Range 96.15-121.44 96.89-103.86 96.40-98.30 95.90-97.6 (° C.) 7 Initial Wt. Ratio of Solvent to Water 6.00 6.72 5.11 4.73 Collected 8 Final Wt. Ratio of Solvent to Water 0.21 0.18 4.15 1.98 Collected 9 Average Wt. Ratio of Solvent to Water 2.77 2.89 2.35 1.87 Collected 10 Total Wt. of Water Collected (g) 166.29 160.54 194.22 241.15 11 Total Wt.
  • the weight ratio of Toluene to furnace oil left behind was 3.09 as per table 7.2 and the weight ratio of benzene to furnace oil left behind was 2.98 as per table 7.3.
  • the process was started by adding toluene 4 times the weight of furnace oil present and then 3 times the weight of furnace oil present.
  • a preferred initial weight ratio of free water to solvent was 1 in both cases.
  • boiling point range for Toluene was 97.28° C. to 98.50° C. and 96.40° C. to 98.30° C. respectively.
  • the weight ratio Benzene was 3 times the weight of furnace oil present and then 2 times the weight of furnace oil present. It was seen that for 3 times benzene, preferred initial weight ratio of free water to solvent was 2. However with 2 times benzene, preferred initial weight ratio of free water to solvent was 1.50 times instead. It was seen that for both these preferred quantum of free water, the boiling temperature range was 80.12-98.59° C. and 86.70-98.31° C. respectively.
  • Relative Centrifugal 5.00 Force in minutes 8 Time taken to de-accelerate to zero RPM 16.35 16.25 9 Total Residence Time in minutes inside 24.25 23.90 centrifuge 10 Temperature of material after Centrifuge (° C.) 33.88 32.98 11 Residual Water in Furnace Oil after 1,17,895 1,12,688 Centrifuge as determined by BTX Process (ppm)
  • weight fraction of bound and unbound water present in sludges were firstly determined and then calculated amount of solvent was added therein followed by heating in a Dean and Stark Apparatus using Mantle Heater. Accordingly, entire bound and free water present in sludge was removed with combined effect of solvent cum heat. Subsequently, entire water was condensed and collected along with part of solvent used. Further, a calculated amount of free water was added to residual matter in RB Flask and once again heated using the same apparatus. Subsequently, entire remaining solvent was removed and collected along with some free water.
  • Ratio of Solvent to 5.53 10.05 Hydrocarbon added 8 Observed Boiling Temperature 101.21-136.61 93.08-108.32 Range (° C.) 9 Initial Wt. Ratio of Solvent to 2.09 5.04 Water Collected 10 Final Wt. Ratio of Solvent to 54.31 50.13 Water Collected 11 Average Wt. Ratio of Solvent to 2.54 6.08 Water Collected 12 Wt. % Water collected during 99.64 99.30 Experiment inclusive of losses 13 Wt. % Solvent collected during 33.31 43.89 Experiment inclusive of losses 14 Wt. Ratio of Solvent to 3.65 5.52 Hydrocarbons Left over in RB Flask at the End of Experiment 15 Residual Water present in left over 329 290 Solvent cum Hydrocarbons in ppm as determined by BTX Process
  • the total furnace oil that was present in sludges retrieved was about 99 wt. %. This was inspite of the fact that a tiny fraction thereof got removed along with solvent collected. It was seen that the furnace oil retrieved was having about 3,806 ppm of residual moisture on an average as against original water content of 2,100 ppm therein. Inspite of slightly higher water content the recovered furnace oil was observed to have a calorific value of 10, 176 kcal/kg on an average as against the value of 10,172 kcal/kg for original furnace oil.
  • free water retrieved from furnace oil sludges was about 96.5 wt. % on an average.
  • the free water recovery for ONGC sludges was 97.3 wt. %.
  • the free water recovery for diesel based sludges was found to be 98.6 wt. %.
  • the free water obtained was in large in quantity and was under process for more than 48 hours with multiple steps.
  • Oil coated sand samples were prepared. These sand samples were treated using solvent like Xylene and thereafter quantitatively and qualitatively the recovery of sand, oils, Xylene and water was evaluated. Firstly, weighed amounts of oils into weighed sand which was water washed, completely dried and very clean. After mixing oils into sand, the oil coated sand samples were washed in separate batches of Xylene. Progressively, oil was moved from sand into Xylene. The washing was stopped once turbidity value and colour of pure Xylene did not change much from its original state after last washing cycle of the sand.
  • Step 2b Separation of Oil and Water by gravity separation & Periodic removal of separated water by keeping material in oven at 90° C. for 48 hours 10 Wt. of Oil recovered inclusive of 0.10 0.15 sticking on glassware (kg) 11 Moisture in Oil after Step 2b as per 3,420 3,123 BTX (ppm) 12 Turbidity of recovered Free Water after 4.2 3.6 Step 2b (NTU)
  • the recovered ONGC free flowing oil was having only 3,420 ppm of residual moisture with a calorific value of 10,580 kcal/kg as against residual moisture of 3,900 ppm and calorific value of 10,652 kcal/kg for original ONGC Oil. It was seen that the recovered furnace oil was having residual moisture of about 3,123 ppm with calorific value of 10,164 kcal/kg as against original furnace oil having residual moisture of 2100 ppm and calorific value of 10,173 kcal/kg. It was seen that the recovered Solvent had barely 153 ppm moisture in it on an average as against 40 ppm moisture in original Xylene used.
  • amount of Xylene required to wash unit mass of oil coated sand depends on both the type of oil that coats the sand and the amount of oil coating the sand.
  • the weight of Xylene required was about 7 times the weight of oily sand for removing 9.2 wt. % ONGC free flowing oil.
  • the weight of Xylene required was instead about 13 times for completely de-oiling the sand that contain 13.12 wt. % Furnace oil.
  • slop oils were prepared with different oils and solvents. These oils/hydrocarbons were added to water in varying parts per million and then vigorously fragmented in high shear mixer at 10,000 RPM over varying time. Subsequently, a representative sample was subjected to Turbidity test at wavelength of 455 nm with Hach Turbidity Meter. The turbidity readings were measured in NTU (Normal Turbidity Unit) thereby taking turbidity values of these slop oils at regular intervals of time till they reached near constant values.
  • NTU Normal Turbidity Unit
  • Benzene failed to easily fragment or remain fragmented into fine droplets even over short periods of time with vigorous stirring in water and therefore Benzene was believed to be not as suitable as Xylene and Toluene for mopping up ultra-fine oil droplets from slop oils. This was indicated by its turbidity values of 8 to 12 NTU as shown in FIG. 7 and FIG. 8 .
  • the turbidity values of transparent liquids were indicative of population density of droplets having diameters of order of 455 nm per unit volume of liquid.
  • Slop Oils contain all sizes of oil droplets. Amongst them, ultra-fines were found to be most difficult to mop up. Benzene was found little less effective than Xylene and Toluene when removal of ultra-fine droplets was an object. It was found that very large droplets of solvents were better suited for removing all oil droplets, other than a fraction of those which were ultra-fine in size. Large droplets of solvents work faster in removing bulk of the oil present. As these were the ones that swept away and then carried with them large numbers of smaller oil droplets while rising up due to buoyancy.
  • FIGS. 9-12 as against FIGS. 13-20 bear testimony to a statement that good solvents coalesce very rapidly unlike hydrocarbons present in the slop oils.
  • the turbidity values of Toluene and Xylene fell down in hours.
  • the turbidity values of Xylene and Toluene fell down sharply with increasing concentration, unlike those of most hydrocarbons. This can be clearly seen by comparing FIG. 9 with FIG. 14 . It was seen that, with solvents, higher concentration did not lead to higher population density of ultra-fine droplets. Instead it triggered instant coalescence.
  • Diesel In case of Diesel, it was seen that Diesel too got fragmented initially but not as much as Toluene and Xylene. It was also seen that Diesel was extremely fast as compared to other hydrocarbons with regard to coalescence, but still not found as fast as that of Toluene and Xylene. After 13 mins of mixing at 10,000 RPM turbidity values for 2,500 ppm Diesel Slop Oil was 3,852 NTU, while for same ppm & RPM, turbidity values of Toluene and Xylene after 5 mins of mixing alone were 54 and 874 NTU respectively. However, as clearly seen in FIG. 21 , Diesel based Slop Oils were found easiest to be processed for recovery of oil and clean water due to rapid coalescing nature.
  • Step 1 Heating of Slop Oil 1 Time Span in minutes 126 5 — 2 Temperature range (° C.) 80-90 95-98 — 3 Turbidity of Slop Oil after heating (NTU) 4,277 4,099 —
  • Step 2 Centrifuging of Slop Oil at 4,500 RCF twice with NIL residence time at peak RCF value 4 Turbidity of Slop Oil after 2nd Centrifuge (NTU) 553 386 797
  • Step 3 Addition of Solvent, Centrifuging it once under same conditions as above and then removal of entire top layer of Solvent + Oil 5 Name & Wt.
  • Step 4 Removal of Solvent from Slop Oil through Boiling with Free Water present therein 8 Turbidity of Slop Oil in NTU on cooling after 14.4 14.6 12.0 addition of make-up water that was lost through boiling
  • Step 5 Addition of Alum with Residence Time in Settling Vessel 9 Wt.
  • Toluene was added to the prepared slop oils. Toluene was mixed in them using high shear mixer at 10,000 RPM for 1 minute. Before addition of Solvent, Slop Oils were tested for turbidity and time was noted. Solvent added samples were allowed to stand for 20 hours for most Oil and Solvent to collect at the top. Later, top layer containing solvent and oil was separated from each Slop Oil Sample and remaining material was tested for turbidity after homogenization and again the time was noted. Subsequently, entire residual solvent was boiled out, in temperature range of 95° C. to 98° C. from remaining material with help from free water present in sop oil. After cooling, make up water was added to replace the water lost through boiling.
  • Solvent was invariably added into slop oils by mixing it for 1 minute at 10,000 RPM. Probably this mixing might have further fragmented existing droplets of Coconut Oil and ONGC Oil and that could have raised turbidity values by increasing the population density of ultra-fine droplets. Impact of further fragmentation was expected to be higher in case of slop oils produced through 1 minute of mixing as compared to those that had been generated after 5 minutes of mixing. Hence turbidity values of slop oils after 1 minute mixing we found to be increasing a lot more. Probably use of solvent might have failed also because most of the solvent got consumed removing large oil droplets. Consequently, ultra fine droplets might have been remained intact with additional need of solvents in batches.
  • centrifuge Time adjusted impact of centrifuge was found to be substantially dependent on starting turbidity values. It progressively reduced turbidity with every successive operation. It was seen that impact of first round of centrifuge was large. In successive rounds, the impact kept diminishing. It was observed that the centrifuge was lot more effective in removing large sized oil droplets since the impact of drag was less on the droplets. It was seen that force of buoyancy worked better with large sized droplets with substantial reduction in turbidity in the first round. It was seen that the centrifuge became ineffective due to one or more of the following reasons. Firstly, centrifuge could have become ineffective once size variations of dispersed oil droplets became narrow. Secondly, centrifuge could have
  • centrifuge could have become ineffective once population density of dispersed droplets falls with increasing mean free path. Thirdly, centrifuge could have become ineffective as initial turbidity values were too large. Fourthly, centrifuge could have become ineffective due to dispersed oil droplets that might have electrically charged. Lastly, centrifuge could have become ineffective due to small density difference between oil and water.
  • centrifuge cannot reduce turbidity of slop oils to the required value of 1 to 4 NTU. In fact, the limiting turbidity values of the centrifuge were lot higher. This was more so in cases of colored slop oils. It was further concluded that the density difference between oil and water and also the RCF and residence time inside the centrifuge play significant role in this regard.
  • slop oils were prepared under conditions given in table nos. 23.1 and 23.3. Subsequently, the turbidity values of slop oils were measured. Thereafter, these slop oils were centrifuged twice with nil residence time at maximum RCF of 4,500. Further, the solvents were added by mixing them into slop oils for 1 minute at 10,000 RPM. Thereafter, the contents were centrifuged once again with nil residence time at maximum RCF of 4,500.
  • test Nos. 2, 3 and 4 in table 23.2 and test Nos. 3 and 4 in Table 23.4 we could not get values because we could quantify the impact of adding solvents to slop oils for these tests as can seen from table Nos. 21.2 & 21.4. However, without quantifying the impact of using solvents, we cannot remove the impact of solvent for these tests.
  • centrifuge must preferentially be used for removing large oil droplets while solvents must be used for removing ultra fine droplets.
  • Solvents must be added only after centrifuge has ceased to be effective for want of wide droplet size distribution or low population density of fine droplets or small density difference between oils and water. This combination was found must when initially turbidity of slop oils was large.
  • slop oil samples were prepared with both low and high turbidity values as per conditions mentioned in below mentioned tables 24.1A and 24.2A.
  • Alum was added and settling time was provided as per figures mentioned in tables 24.1B and 24.2B.
  • Alum was added in 3 different proportions for high turbidity samples and turbidity values were evaluated over 4 days with and without adjusting the effect of time.
  • Turbidity Values including the impact of 4,165 5.44 5.38 9.52 3.59 3.54 time (NTU) 5 Turbidity Values excluding the impact of 4,364 204 204 194 188 188 time (NTU) Day-2 6 Time permitted for Settling (Hrs) 48.06 47.96 47.95 47.95 47.96 47.97 7 Turbidity Values including the impact of 2,468 5.36 3.9 2.53 6.27 2.67 time (NTU) 8 Turbidity Values excluding the impact of 2,634 171 170 105 108 105 time (NTU) Day-3 9 Time permitted for Settling (Hrs) 71.52 71.36 71.34 71.46 71.33 71.28 10 Turbidity Values including the impact of 366 5 2.61 4.72 4.79 3.31
  • Step-1 Addition of Alum with Residence time in Settling Vessel 1 Turbidity of Slop Oil before adding Alum 42.1 90.6 56.1 66.5 (NTU) 2 Wt % of Alum added to Slop Oil 0.05 0.05 0.05 0.05 3 Time permitted for Flocculation of Oil & 5.04 5.84 3.44 4.56 Solids in Settling Vessel (Hrs) 4 Turbidity after Flocculation (NTU) 11.4 92.7 75.9 72.9
  • Step-2 Heating of Alum added Slop Oil 1 Time kept for heating (Hrs) 4 4 1 3 2 Set Temperature of instrument (° C.) 80 80 80 80 3 Average Turbidity of Alum added Slop Oil 2.92 19.1 18.5 10.8 after heating (NTU) 4 Time taken for the process of heating alum 5.11 5.72 3.22 4.43 added Slop oil (Hrs)
  • the slop oil samples were prepared as per conditions mentioned in table 26.1. These samples were filtered repeatedly four times using 40 and 41 Grade Whatman cellulose Filter Papers. In one set of readings the same filter paper was repeatedly used while in the other set of readings new filter papers were used each time. The turbidity values were noted before and after each filtration. The time taken for filtration of a given weight of slop oil was also noted each time to arrive at the rate of filtration.
  • Step-1 Filtration using NO. Whatman Filter paper TEST 1 TEST 2 1 Mode of using Filter Paper Same Filter Each Time Same Filter Each Time Paper used New Filter Paper used New Filter each time Paper used each time Paper used 2 Grade of Whatman Filter 40 41 40 41 40 41 Paper used 3 Turbidity: After 1st 1,971 6,007 2,063 6,543 3,888 4,596 3,918 4,689 Filtration (NTU) 4 Flow Rate of Slop Oil 2.07 13.95 2.4 7.78 7.48 45.43 6.73 91.31 collected for 1st Filtration (g/min) 5 Turbidity: After 2nd 1,096 3,033 1,147 4,370 3,646 4,650 3,373 4,666 Filtration (NTU) 6 Flow Rate of Slop Oil 0.62 2.9 6.95 46.33 7.46 54.13 6.4 82.1 collected for 2nd Filtration (g/min) 5 Turbidity: After 2nd 1,096 3,033 1,147 4,370 3,646 4,650 3,373 4,666 Filtration
  • slop oil samples were prepared under conditions mentioned in below tables 27.1A and 27.2A.
  • Alum was added to these samples after testing for initial turbidity values 0.05 wt. %.
  • the turbidity values of these samples were tested again after close to 24 hours. Further, the samples were successively filtered with Grade 41 and then with Grade 40 Whatman Cellulose Filter Papers and after each filtration reduction in turbidity values were recorded.
  • slop oils were prepared as per conditions mentioned in table nos. 28.1A, 28.2A, 28.3A, 28.4A, 28.5A, 28.6A and 28-7A. Procedures of preparation were also mentioned in table nos. 28.1B, 28.2B, 28.3B, 28.4B, 28.5B, 28.6B and 28.7B. Subsequently, solvents like Toluene and Xylene were used mixed in different proportions.
  • the solvents were mixed with the slop oils using high shear mixer at 8,090 RPM for 1 minute.
  • the oil content in slop oils was varied from 5 PPM to 4, 99,052 PPM.
  • the various oils used were selected from one or more of the following Coconut Oil, Furnace Oil, Diesel, ONGC Free Flowing Oil and ONGC viscous hydrocarbons. Subsequently, all four processing steps involving the use of Centrifuge, Solvent, Alum and Filtration were employed in sequential manner. Accordingly, following observations were made.
  • Step 3 Removal of Solvent from Slop Oils through Boiling with Free Water present therein 7 Average Turbidity of Slop Oils in 6 12 42 54 NTU on cooling after addition of make-up water that was lost through boiling
  • Step 4 Addition of Alum with Residence Time in Settling Vessel 8 Wt.
  • Step 4 Removal of Solvent from Slop Oil through boiling with free water present therein 9 Average Turbidity of Slop Oil in NTU 14 10 31 on cooling after addition of make-up water that was lost through boiling
  • Step 5 Addition of Alum with Residence Time in Settling vessel 10 Wt.
  • Step 3 Removal of Solvent from Slop Oil through Boiling with Free Water present therein 6 Average Turbidity of 31 42 35 37 39 40 Slop Oil in NTU on cooling after addition of make-up water that was lost through boiling
  • Step 4 Addition of Alum with Residence Time in Settling Vessel 7 Wt.
  • Step 4 Removal of Solvent from Slop Oil through boiling with Free Water present therein 9 Average Turbidity of Slop Oil in NTU 236 220 238 on cooling after addition of make-up water that was lost through boiling
  • Step 5 Addition of Alum with Residence Time in Settling Vessel 10 Wt.
  • the slop oils were prepared with Coconut Oil under conditions as mentioned below in table 29.1. These slop oil samples were retained in a separating flask for 48 hours that lead to formation of three layers. The top layer obtained was containing pure oil. The middle layer obtained was containing oil and water both while the bottom layer was containing mostly water with little Oil therein. The bottom layer was removed and treated as slop oil along with slop oil coming from middle layer as explained below.
  • the middle Layer was treated with Alum and retained in Separating Flask for another 48 hours that lead to further formation of three layers, i.e. top layer containing pure oil, middle layer containing oil and alum with water and bottom layer of slop oil.
  • the layer containing alum was dried and tested for Calorific Value.
  • the weight percent recovery of pure coconut oil from top and middle layers and calorific value of dried alum layer can be seen in table 29.2 while results of treatment of slop oil along with weight percent recovery of coconut oil cum solvent can be seen in table 29.3.
  • Step 4 Removal of Solvent from Slop Oil through Boiling with Free water present therein 9 Average Turbidity of Slop Oil in NTU 60 53 on cooling after addition of make-up water that was lost through boiling
  • Step 5 Addition of Alum with Residence Time in Settling Vessel 10 Wt.
  • Step 4 Removal of Solvent from Slop Oil through Boiling with Free Water present therein 9 Average Turbidity of Slop Oil in NTU 140 33 after addition of make-up water that was lost through boiling (NTU)
  • Step 5 Addition of Alum with Residence time in Settling Vessel 10 Wt.

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US20170073591A1 (en) * 2014-03-02 2017-03-16 Nagaarjuna Shubho Green Technologies Private Limited Process for removal of water (both bound and unbound) from petroleum sludges and emulsions with a view to retrieve original hydrocarbons present therein
TWI671523B (zh) * 2018-12-11 2019-09-11 中國鋼鐵股份有限公司 污泥混合均勻度檢驗方法
US11130075B2 (en) * 2016-05-10 2021-09-28 Rocco Slop Ab Method and system for purification of slop oil and industrial emulsions comprising two processes run in parallel
US11332677B2 (en) 2020-05-07 2022-05-17 Saudi Arabian Oil Company Enhanced demulsifier performance ranking procedure and algorithm based on separation efficiency
US11471791B2 (en) * 2015-11-30 2022-10-18 Hindustan Petroleum Corporation Limited Process for separating a hydrophibic material from a mixture of hydrophobic and hydrophilic material
US11958004B2 (en) 2019-02-08 2024-04-16 Skf Recondoil Ab Method and system for purification of contaminated oil
US12097453B2 (en) 2019-02-08 2024-09-24 Skf Recondoil Ab Method and system for circular use of industrial oil

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MY202431A (en) * 2019-01-29 2024-04-29 Seechem Horizon Sdn Bhd Method for recovering hydrocarbons from waste sludge
CN110407422B (zh) * 2019-07-24 2020-08-14 湖南省计量检测研究院 一种石化油泥的资源化处理方法
CN115671798A (zh) * 2021-07-22 2023-02-03 中国石油天然气股份有限公司 一种原油采出液及老化油脱水工艺
CN115677095B (zh) * 2022-10-24 2023-09-26 江苏金润环保工程有限公司 一种电镀污水零排放处理装置及其处理工艺

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US20170073591A1 (en) * 2014-03-02 2017-03-16 Nagaarjuna Shubho Green Technologies Private Limited Process for removal of water (both bound and unbound) from petroleum sludges and emulsions with a view to retrieve original hydrocarbons present therein
US11471791B2 (en) * 2015-11-30 2022-10-18 Hindustan Petroleum Corporation Limited Process for separating a hydrophibic material from a mixture of hydrophobic and hydrophilic material
US11130075B2 (en) * 2016-05-10 2021-09-28 Rocco Slop Ab Method and system for purification of slop oil and industrial emulsions comprising two processes run in parallel
TWI671523B (zh) * 2018-12-11 2019-09-11 中國鋼鐵股份有限公司 污泥混合均勻度檢驗方法
US11958004B2 (en) 2019-02-08 2024-04-16 Skf Recondoil Ab Method and system for purification of contaminated oil
US12097453B2 (en) 2019-02-08 2024-09-24 Skf Recondoil Ab Method and system for circular use of industrial oil
US11332677B2 (en) 2020-05-07 2022-05-17 Saudi Arabian Oil Company Enhanced demulsifier performance ranking procedure and algorithm based on separation efficiency

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