WO2014091498A4

WO2014091498A4 - Treatment of crude oil, sludges and emulsions

Info

Publication number: WO2014091498A4
Application number: PCT/IN2013/000764
Authority: WO
Inventors: Dhruva Jyoti DASGUPTA
Original assignee: Nagaarjuna Shubho Green Technologies Private Limited
Priority date: 2012-12-13
Filing date: 2013-12-11
Publication date: 2015-07-16
Also published as: GB201511405D0; AU2013358575A1; US20150322348A1; GB2523517A; MX2015007576A; WO2014091498A3; WO2014091498A2; NO20150745A1; CN104903244B; BR112015013732A2; CN104903244A; EA201591066A1; CA2894026A1

Abstract

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

Claims

AMENDED CLAIMS

received by the International Bureau on 16 May 2015 (16.05.15)

A process for treatment of a sludge mixture having hydrocarbons with bound water, unbound water, dissolved and un-dissolved solids therein, the process for treatment of the sludge mixture comprising the steps of:

a) Centrifuging the sludge mixture in a first centrifuge provided the sludge mixture splits into various components, the first centrifuge being a batch or Multi-Pass centrifuge, the said centrifuge forming a viscous hydrocarbon layer, a slop oil layer and a free flowing hydrocarbon layer; b) Desalting the viscous hydrocarbon layer from step a)in a first desalter followed by optional treatment thereof in a heat based low volatiles stripping vessel for removing vapors of low boiling liquid hydrocarbons therefrom;

c) Condensing the vapors of low boiling liquid hydrocarbons from step b) in a first condenser for obtaining low boiling liquid hydrocarbons along with water for use;

d) Optionally desalting crude hydrocarbons coming from a group collection center in a second desalter for obtaining desalted product crude and removal of abound water containing hydrocarbon layer followed by mixing the bound water containing hydrocarbon layer with the viscous hydrocarbon layer from the first centrifuge;

e) Desalting the free flowing hydrocarbon layer from step a) in a third desalter for entire removal of salts therefrom;

f) Homogenizing the viscous hydrocarbon layer from step b) in a homogenizer by adding a first predefined amount of solvent for forming a volatiles free non- viscous homogenized stream therefrom;

g) Performing BTX and Ash tests of the non-viscous homogenized stream from step f) followed by treatment thereof in an agitator cum homogenizer thereby adding a second predefined amount of solvent therein in accordance with the BTX and Ash tests results;

h) Centrifuging the non-viscous homogenized stream from step g) in a second centrifuge for separating a bound water dominant hydrocarbon stream, an unbound water dominant or water free hydrocarbon stream and the slop oil therefrom;

i) Optionally treating the non-viscous homogenized stream from step g) in a hot insulated settling tank for removal of water free solvent along with hydrocarbons therefrom;

j) Heating the unbound water dominant or water free hydrocarbon stream from step h) in a first heating vessel thereby optionally adding a predefined amount of free water therein, the first heating vessel operating at a first predefined temperature range thereby forming a first residual phase and a first vapor phase therein;

k) Heating the bound water dominant hydrocarbon stream from step h) in a second heating vessel at a second temperature range thereby optionally adding a third predefined amount of additional solvent therein, the second heating vessel forming a second residual phase and a second vapor phase therein;

1) Centrifuging the first residual phase from step j)in a hot centrifuge at a second predefined temperature for obtaining volatiles free desalted product hydrocarbons in a range of about 96 wt% to 100 wt% along with unbound water having turbidity at least below 20 NTU;

m) Treating the second residual phase from step k) in the first heating vessel; and

n) Condensing the first vapor phase from step j) and the second vapor phase from step k) through a second condenser for obtaining almost 100% solvent, the bound water in a range of about 99 wt% to 100 wt % wherein the free water in a range of about 94 wt. % to 100 wt. % is collected through entire process, the solvent being reused in said process.

The process for treatment of the sludge mixture as claimed in claim 1, wherein the first centrifuge substantially reduces quantum of the sludge mixture with bound water that facilitates further processing with reduced cost and time in downstream processing of said process. 202

3. The process for treatment of the sludge mixture as claimed in claim 1, wherein the free flowing hydrocarbon layer is about 41 wt% typically having 3,864 ppm water and 0.88 wt.% ash with calorific value ofl0,635 kcal/kg.

The process for treatment of the sludge mixture as claimed in claim 1, wherein 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 process for treatment of the sludge mixture as claimed in claim 1, wherein the first centrifuge enhances separation between the components present in the sludge by extending a period of residence time of the sludge thereby gradually varying revolutions per minute of the batch centrifuge enabling collection of slop oil behind the viscous hydrocarbon layer.

The process for treatment of the sludge mixture as claimed in claim 1, wherein 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 process for treatment of the sludge mixture as claimed in claim 1, wherein the first desalter, the second desalter and the third desalter prevent needless repetition of identical processes being done in group collection center for removal of bound and unbound water from crude again into refineries after desalting of the crude.

The process for treatment of the sludge mixture as claimed in claim 1, wherein the first desalter, the second desalter and the third desalter prevent ingression of water into various product hydrocarbon streams in refineries thereby preventing accumulation of sludge in downstream of said process and in vessels utilized in refinery onward processes. 203

9. The process for treatment of the sludge mixture as claimed in claim 1, wherein 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.

10. The process for treatment of the sludge mixture as claimed in claim 1, wherein the first desalter, the second desalter and the third desalter prevent possibility of corrosion of pipelines and tankers during transportation. 11. The process for treatment of the sludge mixture as claimed in claim 1, wherein the heat based stripping vessel separates the low volatiles from the viscous hydrocarbon layer for preventing co-distillation of the low volatiles with the solvent during removal of the bound water with solvent in downstream of said process.

12. The process for treatment of the sludge mixture as claimed in claim 1, wherein removal of the bound water from the hydrocarbon layer allows removal of heavy metal, Ash and salts therefrom for effectively improving commercial value.

13. The process for treatment of the sludge mixture as claimed in claim 1, wherein the BTX and Ash tests help assist in determination of an optimum amount of solvent to be added in said process. 14. The process for treatment of the sludge mixture as claimed in claim 1, wherein the solvent reduces viscosity for removal of bound water from topmost layer of the non-viscous homogenized stream on account of viscosity. 15. The process for treatment of the sludge mixture as claimed in claim 1, wherein the solvent help assists in homogenization of the sludge that in turn helps in sampling and accurate determination of water and Ash content. 204

16. The process for treatment of the sludge mixture as claimed in claim 1, wherein the solvent is added in said process only for viscous portion of the hydrocarbons which substantially reduces overall use of solvent in said process.

17. The process for treatment of a sludge mixture as claimed in claim 1, wherein the solvent is selected from the group of Benzene, Toluene, Xylene and similar Azeotropes of water.

18. The process for treatment of the sludge mixture as claimed in claim 14, wherein the solvent removes the bound water from the top most layer with least possible thermal damage to the product hydrocarbon stream in said top most layer.

19. The process for treatment of the sludge mixture as claimed in claim 1, wherein the solvent stream and the second centrifuge mutually remove substantial bound water from the viscous hydrocarbon layer at an ambient temperature.

20. The process for treatment of the sludge mixture as claimed in claim 1, wherein the solvent depresses the boiling point of the bound water.

21. The process for treatment of the sludge mixture as claimed in claim 1, wherein the solvent is added in a range of about 1.8 to 100 times the weight of water present in the sludge for entire removal of the bound water.

22. The process for treatment of the sludge mixture as claimed in claim 1, wherein the solvent has a left over weight ratio of solvent to hydrocarbon in a minimum range of 2.00 to6.00 for entire removal of the bound water at least temperature. 205

The process for treatment of the sludge mixture as claimed in claim 1, wherein the first predefined temperature of the first heating vessel is in a range of about 90°C- 105°C.

The process for treatment of the sludge mixture as claimed in claim 1, wherein the hot centrifuge has a temperature in a range of about 80 °C to 94°C.

25. The process for treatment of the sludge mixture as claimed in claim 1, wherein the hot centrifuge is a hot settling tank that ensures adequate reduction in viscosity of hydrocarbons thereby allowing settling of free water therein over a predefined period of time.

26. The process for treatment of the sludge mixture as claimed in claim 25, wherein the hot settling tank is operated under high pressure for increasing the operating temperature range for further reducing the viscosity of the hydrocarbon thereby facilitating faster removal of free water without leading to boiling of water therein. 27. The process for treatment of the sludge mixture as claimed in claim 1, wherein the second heating vessel is preferably a multi effect evaporator preferably with a thermal vapor recompression to avoid thermal cracking of the product hydrocarbon stream. 28. The process for treatment of the sludge mixture as claimed in claim 1, wherein the second heating vessel includes a foam breaker and an entrainment separator adapted to avoid entrainment of hydrocarbons in condensate. 29. The process for treatment of the sludge mixture as claimed in claim 1, wherein the first heating vessel includes a foam breaker and an entrainment separator adapted to avoid entrainment of hydrocarbons in the condensate. 206

30. The process for treatment of the sludge mixture as claimed in claim 1, wherein the second heating vessel maintain a controlled rate of heating with an optimum ratio of residual solvent to dehydrated Hydrocarbon for entire removal of bound water from the hydrocarbon.

31. The process for treatment of the sludge mixture as claimed in claim 1, wherein the bound water obtained is high quality usable water that requires minimal treatment for being used as a drinking water.

32. The process for treatment of the sludge mixture as claimed in claim 1, wherein the first and second heating vessels are provided with waste heat for reducing cost of energy in said process.

A process for treatment of slop oil containing water, solids, salts and hydrocarbons with or without bound water, the process for treatment of slop oil comprising steps of:

a) Centrifuging the slop oil through a fourth centrifuge for obtaining the slop oil with low turbidity by connecting most oil present in a thin top layer;

b) Treating the above slop oil from step a) in a high speed shear mixer by adding a solvent to form a mixture followed by centrifuging thereof in a fifth centrifuge for obtaining a water dominant hydrocarbon layer and a solvent dominant hydrocarbon layer therefrom;

c) Performing BTX and Ash tests of the solvent dominant hydrocarbon layer from step b)for bound water therein followed by a heat treatment thereof in a third heating vessel and a fourth heating vessel, the third vessel having a predefined amount of solvent added therein, the fourth vessel having a predefined amount of free water added therein, the third heating vessel and fourth heating vessel separating a vapor phase from a liquid phase, the vapor phase having entire remaining solvent and part of 207

free water therein, the liquid phase having hydrocarbons with limited solids, limited salts, free water and alum therein;

d) Centrifuging the liquid phase from step c)through a sixth centrifuge operating at a predefined temperature for separating a product hydrocarbon layer from a water layer, the water layer having limited salts, limited solids and alum therein;

e) Treating the water layer from step d)through a first reverse osmosis plant for obtaining water for use and a reject stream therefrom;

f) Condensing the vapor phase from step c)through a third condenser for obtaining solvent for being reused in the high speed shear mixer and water for use therefrom;

g) Heating the water dominant hydrocarbon layer from step b) in a fifth heating vessel for separating vapors of solvent therefrom followed by condensing thereof in the third condenser to obtain solvent for reuse and water for use therefrom, the fifth heating vessel producing a liquid phase having remaining water, limited hydrocarbons, salts and solids with a substantially low turbidity;

h) Treating the liquid phase from step g) in a settling tank followed by addition of a predefined amount of alum therein, the settling tank forming a water dominant alum layer and a gelatinous oil bearing layer therein;

i) Filtering the water dominant alum layer from step h) in a filtration unit, the filtration unit separating the water dominant alum layer into a filtrate stream and a residual stream, the filtrate stream having water, alum and salts therein, the residual stream having wet solids with traces of hydrocarbons, salts and alum therein;

j) Treating the filtrate stream from step i) in a second reverse osmosis plant for recovering usable water therefrom;

k) Mixing the residual stream from step i) with the gelatinous oil bearing layer followed by drying thereof in a first hot dryer for obtaining a viscous liquid containing hydrocarbons, alum, solids and salts; 208

1) Agitating the viscous liquid from step k) in an agitator cum de-oiling unit by adding a predefined solvent therein followed by treatment thereof through a seventh centrifuge for obtaining a water layer, a cake layer and a solvent layer thereby adding water therein, the water layer having alum, salts and limited solvent therein, the cake layer having cake of de-oiled solids with solvent, limited salts and limited alum therein;

m) Treating the water layer from step 1) in a sixth heating vessel for obtaining vapors of solvent and water followed by treatment thereof through a fourth condenser for obtaining solvent for reuse and water for use or further treatment in said process;

n) Treating the solvent layer from step 1) in the fourth heating vessel for recovery of solvent therefrom; and

o) Treating the cake layer from step 1) in a second hot dryer for recovery of solvent through the condenser, the second hot dryer producing dried de- oiled solids having traces of alum and salts therein.

The process for treatment of the slop oil as claimed in claim 33, wherein the slop oil with more than 10,000ppm hydrocarbon content is subjected to a pre-treatment comprising the steps of:

a) 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;

b) Treating the water dominant layer in a second settling tank by adding a predefined amount of alum therein, the second settling tank forming a substantially unbound water-free hydrocarbon layer, a gelatinous oil bearing layer and an alum containing slop oil having hydrocarbon content less than 10,000 PPM; and

c) Optionally centrifuging the gelatinous oil bearing layer from step b) in a third centrifuge by adding a predefined amount of solvent therein, the third centrifuge forming a solvent layer containing Alum along with 209

solid coated with hydrocarbons, the solvent layer containing Alum is separated into solvent and residual hydrocarbons by azeotropic boiling with water in said process.

35. The process for treatment of the slop oil as claimed in claim 33, wherein the third heating vessel is preferably a multiple effect evaporator preferably with a thermal vapor recompression adapted to avoid thermal cracking of the product hydrocarbon.

36. The process for treatment of the slop oil as claimed in claim 33, wherein the third heating vessel has a temperature in a range of about 70°C- 150°C.

37. The process for treatment of the slop oil as claimed in claim 33, wherein the fourth heating vessel has a temperature in a range of about 90°C to 105°C.

38. The process for treatment of the slop oil as claimed in claim 33, wherein the fifth heating vessel has a temperature in a range of about 90°C to 105°C.

The process for treatment of the slop oil as claimed in claim 33, wherein the sixth centrifuge is a hot centrifuge that has a temperature of about 80 °C to 94°C.

The process for treatment of the slop oil as claimed in claim 33, wherein the sixth centrifuge is a hot settling tank that has a temperature of about 80 °C to 94 °C.

The process for treatment of the slop oil as claimed in claim 40, wherein the hot settling tank is operated under high pressure such that an operating temperature is further increased to reduce the viscosity of hydrocarbon for faster removal of free water without leading to boiling of water present therein. 210

42. The process for treatment of the slop oil as claimed in claim 33, wherein the BTX and Ash tests help assist in determination of amount of solvent to be added in said process.

43. The process for treatment of the slop oil as claimed in claim 33, wherein the solvent is selected from the group of Benzene, Toluene, Xylene and other azeotropes of water.

44. The process for treatment of the slop oil as claimed in claim 33, wherein the first hot dryer has a temperature of about 108°C.

45. The process for treatment of the slop oil as claimed in claim 33, wherein the first reverse osmosis plant removes alum, salts and solids to produce water of usable quality.

46. The process for treatment of the slop oil as claimed in claim 33, wherein the sixth heating vessel is an evaporator.

47. The process for treatment of the slop oil as claimed in claim 33, wherein the sixth heating vessel has a temperature in a range of about 90°C to 105°C.

48. The process for treatment of the slop oil as claimed in claim 33, wherein the second hot dryer has a temperature of about 200°C.

49. The process for treatment of the slop oil as claimed in claim 33, wherein the third centrifuge helps to quickly separate the solvent cum hydrocarbon layer and the gelatinous oil bearing layer from slop oil.

50. The process for treatment of the slop oil as claimed in claim 33, wherein addition of alum in the second settling tank neutralizes surface charge. It facilitates speedy separation of the hydrocarbons through flocculation and formation of the gelatinous oil bearing layer. 211

The process for treatment of the slop oil as claimed in claim 33, wherein 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 due to size variations of dispersed oil droplets becoming narrow, population density of dispersed oil droplets falling with increase in mean free path and a plurality of residual droplets being electrically charged along with very small density difference between phases.

The process for treatment of the slop oil as claimed in claim 51, wherein said lacuna of the fourth centrifuge gets magnified when starting turbidity value of the slop oil is very high.

The process for treatment of the slop oil as claimed in claim 51, wherein the solvent is added through the high shear mixer when the fourth centrifuge reaches its limiting value.

The process for treatment of the slop oil as claimed in claim 51, wherein addition of solvent enhances the operating range of the 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 process for treatment of the slop oil as claimed in claim 51, wherein the fourth centrifuge again reaches a limiting value after addition of the solvent and at that point the residual solvent present therein is boiled out with free water in a temperature range of about 90 °C to 99 °C.

The process for treatment of the slop oil as claimed in claim 33, wherein addition of alum in third settling tank when the slop oil is having turbidity below 90 NTU to electrically discharge finest droplets of the hydrocarbons and flocculate them thereby reducing turbidity by 90 %- 99 %. 212

57. The process for treatment of the slop oil as claimed in claim 33, wherein settling with addition of alum is a slow process by itself but it can be speeded up by applying heat such that effectiveness of alum treatment is dependent on temperature and time.

58. The process for treatment of the slop oil as claimed in claim 33, wherein the filtration unit brings down the turbidity value of the slop oil below 1 NTU. 59. The process for treatment of the slop oil as claimed in claim 33, wherein the filtration unit has an effectiveness that substantially depends on pore size of filtering media of the filtration unit and nature of hydrocarbons present in the slop oil. 60. A process for treatment of a sludge mixture comprising of a centrifuge, the process for treatment comprising the steps of:

Centrifuging the sludge containing hydrocarbons, bound and unbound water, salts and solids in a centrifuge to break the binding between the components present by increasing residence time of the sludge in the centrifuge thereby forming a viscous hydrocarbon layer with bound water, salts and solids, a free flowing hydrocarbons layer with limited salts and solids and a free water layer with limited solids and salts, the centrifuge repositioning the viscous hydrocarbon layer from a back side to a middle side therein by slowly increasing revolutions per minutes thereof, the centrifuge slowly decreasing an angle between a vertical axis of a container and a horizontal plane thereof thereby gradually reducing but not allowing said angle to become 0°.

The process for treatment as claimed in claim 60, wherein the quantity of sludge mixture with bound water is reduced thereby saving further processing cost and time. 213

62. The process for treatment as claimed in claim 60, wherein the centrifuge itself gives a large amount of marketable product hydrocarbons, namely free flowing hydrocarbons.

63. A process for treatment of sludge mixture with combined effect of centrifuge and solvent, the sludge mixture containing bound and unbound water, salts and solids therein, the process for treatment comprising the steps of:

a) Adding a predefined amount of solvent in the viscous hydrocarbon emulsion, followed by mixing thereof, the solvent reducing the viscosity of the viscous hydrocarbon layer.

b) Centrifuging the solvent dominant viscous hydrocarbon layer from step a) in the centrifuge to obtain a large layer of solvent and hydrocarbon, a layer containing hydrocarbons and bound water and a free water layer, the centrifuge having an extended residence time for getting less of sludge with bound water therein;

c) Treating the large layer of solvent and hydrocarbon in step b) for recovering solvent by boiling through free water in a temperature range of 90 °C to 99 °C at an atmospheric pressure.

The process for treatment as claimed in claim 63, wherein the mass of sludge mixture with bound water is reduced thereby saving further processing cost and time.

The process for treatment as claimed in claim 63, wherein this centrifuge gives further amount of marketable product hydrocarbons, namely free flowing hydrocarbons.

214

STATEMENT UNDER ARTICLE 19(1) (RULE 46.4)

FOR PCT/IN2013/00764

The applicant respectfully submits his response to Box No. V and Box No. VIII in the Written Opinion of the International Searching Authority.

Applicant submits that the originally filed independent Claim 33 has been deleted and reproduced as a dependent Claim 34 in the present amendment. Moreover, Applicant has deleted the words "the first heating vessel" from the amended Claim 34 in order to overcome objection raised by International Searching Authority in Box No. VIII of the written opinion. Accordingly, Claim 34 now appears to be the only independent claim 34 in said Group-ll of claims 33-59. Hence, Applicant has further amended the "as filed" dependent claims 35-40, 42-51 and 56-59 in order to be dependent on independent claim 33.

Applicant has amended the originally filed Claim 26 thereby deleting the words "slop oil" and adding the words "sludge mixture" in said claim to overcome objection raised by International Searching Authority in Box No. VIII of said written opinion.

Applicant has amended the originally filed Claim 63 thereby deleting the word "layer from step a)" and adding the word "emulsion" therein in order to bring clarity in said Claim 63.

Applicant believes that no new matter has been added during the present amendments. Hence, these amendments are believed to be allowable amendments.