THE NOVEL PROCESS FOR RECLAMATION OF OIL IN WATER EMULSION COLLECTED FROM CRUDE OIL DE-SALTER BRINE WATER

Field of the invention:

The present invention relates to crude oil refining process, more specifically to effluent treatment process (ETP) where crude oil de-salter brine water received for processing, further more specific to oil-in-water emulsion collected after ETP process from de-salter brine water.

Background of the invention:

Crude oil is natural fossil fuel extracted from earth, sometime synthetic material also mixed with it. After exploration and cleaning process, crude oil mainly consist of mixture of hydrocarbon and trace quantity of water and sediments. The concentration of water and sediments are vary based on types of crude oil, source of crude oil and cleaning process employed after exploration. Presence of water and sediments has many disadvantage in refining process.

To minimize fouling, corrosion and frequent breakdown, removal of water and sediments is must before it entering into crude oil distillation (CDU) process. Most of refinery using de-salting process to remove water with dissolved salt and sediments from crude oil just before crude oil distillation process.

Crude oil is heated at around 145 °C and 5 to 6% fresh de-saline water added to dilute the existing water soluble salts, then after proper mixing it enter into de-salter vessel. In de-salter, an oil-water mixture put into settling vessel, where water with dissolved salt & sediments/ sludge particles get separated and settled at bottom portion of vessel called brine water which drained from bottom valve. The de-salted crude oil from top layer of vessel send to the distillation process. The electric current applied to promote phase separation and settling effect.

During brine water & sediments / sludge draining process, small quantity of crude oil also get carryover with brine water, which needs to be recollect to save the fuel as well as to minimize losses. The quantity of oil in brain water depends on the de-salter technology, type of crude oil under process, condition of de-salter unit and standard operating procedure being followed. The de-salter brine water test results indicate that, the oil quantity is in the range of few ppm to 10% level.

For recollection of oil from de-salter brine water, it has to pass through many settling stages with or without chemical, mechanical & heating treatments at ETP.

The collected oil-in-water emulsion after existing ETP treatment also called de-salter slop oil or emulsion. The crude oil refinery, collecting de-salter slop oil emulsion form existing ETP process is in the range of 0.2 to 1.0% of its crude oil throughput. The collected oil- in-water emulsion is in very tight form, hence further separation of water and sediments not possible by existing normal effluent treatment process.

For example, 20 MMTPA crude oil refinery, generate approximately 1277000 M3 of brine water per year and collect oil-in-water emulsion in the range of 40000 to 200000 MT/ Year.

The analysis data of de-salter slop oil emulsion indicate that, it mainly consist of 20 to 70 vol. % heavy hydrocarbons, 29 to 78 vol. % water and 1 to 10 vol % sediments which are in very tight emulsion form, also there are presence of many undesirable metal elements viz iron, sodium, calcium, magnesium, aluminium, silica, chloride, sulphate etc.

De-salter oil-in-water emulsion collected after treatment at ETP can be either reprocess at refinery or can be disposed of according to legal compliance process. Reprocessing at refinery is a cheap option than any other options. Hence de-salter oil-in-water emulsion collected after treatment at ETP is being reprocessing with crude oil at Nayara Energy since inception. The quantity of emulsion generated at ETP and reprocessed at CDU during 2019 was approx. 154000 M3.

Due to huge quantity and worst quality of de-salter slop oil emulsion, crude oil refinery facing many problems while reprocessing emulsion even at lower concentration (<1 % ) of crude throughput viz

1) The huge quantity of emulsion is reducing refining capacity and increasing processing cost hence it has very big financial impact on GRM due to high reprocessing cost (2 to 4 USD / barrel of emulsion), also consume extra energy at different stages, require multiple storage, treatment and handling facilities ( tanks, chemicals, mechanical and heating resources). It has adverse impact on environment as well as it increase hazardous risk.

2) The worst quality of emulsion (high level of water and sediment in tight emulsion form) is destabilize de-salter & CDU operation, generating more slop oil during de-salting process and creating vicious cycle of emulsion.

3) Some time, oil-in-water emulsion generation is very high and it is difficult to manage inventory, hence it become compulsion to reprocess within time frame even at the cost of more CDU throughput loss.

4) It increase fouling, corrosion and frequent breakdown.

5) It also impacting on aviation turbine fuel (ATF) production with respect to deteriorating of ATF colour.

There are many literature indicate the separation of water from crude oil, refinery slop oil, oily sludge etc. by different technology viz settling, filtration, centrifuge, chemical emulsification, microwave irradiation, ultrasonic irradiation etc.

The use of ultrasonic irradiation is known for breaking crude oil hydrocarbon / water emulsion as described in U.S. patent 2257997, 3200567, 3594314 and W02004/033377A1 and GB 2274850. However none of these patent directly deals with oil in water emulsion collected after treatment at ETP from de-salter brine water. Therefore it would be great benefit to the refining world by providing a reclamation process for emulsion collected after treatment at ETP from crude oil de-salter brine water, which can reduce emulsion quantity and or improve its quality, moreover it will resolve various problems face by refiner at CDU & de-salter process due to reprocessing of emulsion.

The present ETP process and technology has limitation to further reduce quantity and or to improve quality of emulsion because of very tight emulsion. As per the literature, yet there is no any solution known to us which is adopted by petroleum refining industry or may be technology not commercially viable.

Looking to the above problems, crude oil refiner always strives to reduce quantity of emulsion generation as well as to improve its quality. Therefore, there is a need to develop more effective effluent treatment process (ETP) where crude oil de-salter brine water received for processing to recollect oil. Object and summary of the invention:

The main object of this invention is to develop a better process for reclamation of oil-in- water emulsion collected after treatment at ETP from crude oil de-salter brine water.

Another objective of the present invention is to develop a better process for reduction of emulsion quantity.

Another objective of the present invention is to develop a better process to improve emulsion quality.

Another objective of the present invention is to reduce water from emulsion.

Another objective of the present invention is to reduce sediments from emulsion.

Another objective of the present invention is to reduce water soluble metal elements.

Another objective of the present invention is to reduce metal elements bonded with sediments (organometallic molecules).

Another objective of the present invention is to reduce processing problems experienced at crude oil de-salting & distillation by petroleum refiner.

Another objective of the present invention is to provide easily implementable process at low cost.

Another objective of the present invention is to reduce water from emulsion.

In order to achieve the afore-said objectives, the present invention provides a novel process for reclamation of oil-in-water emulsion collected after treatments at ETP from crude oil de-salting brine water.

As per the first aspect, the present invention provides a twostep process, wherein, in first step, oil in water emulsion collected after treatment at ETP from crude oil de-salter brine water at ETP is treated with novel radiation technique which separate maximum water and partially sediments and convert in to water in oil emulsion. In the second stage, partially reclaimed oil is mixed with aromatic solvent and centrifuged to separate residual water and sediments from emulsion.

Description of the drawings:

The foregoing and further objects, features and advantages of the present subject matter will become apparent from the following description of exemplary embodiments with reference to the accompanying drawings, wherein like numerals are used to represent like elements.

It is to be noted, however, that the appended drawings illustrate only typical embodiments of the present subject matter, and are therefore, not to be considered for limiting of its scope, for the subject matter may admit to other equally effective embodiments.

Figure 1 illustrates the basic reclamation process for oil-in-water emulsion collected from crude oil de-salter brine water at ETP unit, which reduce emulsion quantity, reduce water from emulsion, reduce water soluble metal impurities, reduce organometallic impurities and hence it improve quality of emulsion also. Moreover it will resolve various problems face by refiner at CDU & de-salter process due to reprocessing of emulsion.

Figure 2 illustrates the microscopic image of the oil-in-water emulsion [10], ultrasonic treated oil [13], reclaimed oil [16], and separated water with sediments [12, 14].

Figure 3 illustrates Bl is oil-in-water emulsion [10] and B2 the qualitative visual separation of oily layer at top and water with sediments at bottom in laboratory scale batch ultrasonic treatment experiment.

Figure 4 illustrates BIO is change in appearance of emulsion after 120 minute irradiation time in pilot scale batch process. Detailed description of the invention:

The following presents a detailed description of various embodiments of the present subject matter with reference to the accompanying drawings.

The embodiments of the present subject matter are described in detail with reference to the accompanying drawings. However, the present subject matter is not limited to these embodiments which are only provided to explain more clearly the present subject matter to a person skilled in the art of the present disclosure. In the accompanying drawings, like reference numerals are used to indicate like components.

The specification may refer to "an", "one", "different" or "some" embodiment(s) in several locations. This does not necessarily imply that each such reference is to the same embodiment(s), or that the feature only applies to a single embodiment. Single features of different embodiments may also be combined to provide other embodiments.

As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless expressly stated otherwise. It will be further understood that the terms "includes", "comprises", "including" and/or "comprising" when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. It will be understood that when an element is referred to as being "attached" or "connected" or "coupled" or "mounted" to another element, it can be directly attached or connected or coupled to the other element or intervening elements may be present. As used herein, the term "and/or" includes any and all combinations and arrangements of one or more of the associated listed items.

The figures depict a simplified structure only showing some elements and functional entities, all being logical units whose implementation may differ from what is shown.

The present invention provides a process for reclamation of oil-in-water emulsion which is verified by using actual oil-in-water emulsion collected from ETP unit and experimental work done with laboratory scale & pilot scale equipment.

The present process is first time applied for oil in water emulsion collected after treatment at ETP from crude oil de-salter brine water. As per the first aspect Figure 1 represent the invented process, where the crude oil blend [1] mixed with emulsion (extracted oil) [19] and other refinery slop oil [20] and feed to the de-salter system [2] to remove water with dissolve salt and sediments, de-salted crude oil [3] from top send to CDU process and brine water [4] drained from de-salter bottom out let send to settling pond [5] and then emulsion skimmed off from top surface of pond by belt system or other suitable system. The oil-in-water emulsion [7] send to next settling tank [8]. After draining separated water [9] from bottom, the oil-in-water emulsion [10] send to ultrasonic treatment system [11], where separated water with sediments [12] from bottom send to ETP process [21] for further treatment and from top, improved quality oily emulsion layer [13] send to centrifuge process [14] where approx. 50 % volume of aromatic solvents added, after centrifuging, separated water & sediments drained from bottom [18] and reclaimed (extracted) oil with solvent [19] send to de-salter feed for reprocess. Basic drawing of ultrasonic system [11] attached here separately.

De-salting Treatment:

Crude oil received at COT tankage through Jetty. After settling and draining of water, it is pump to refinery for refining process. Crude oil blend [1] is prepared through on-line blending system from various crude oil to meet the crude oil distillation unit feed criteria. As explained in figure 1, collected emulsion at ETP [19] + refinery slop oil [20] generated from other refinery processes is transport via pipeline for reprocessing and mixed with crude oil blend [1]. Adequate quantity (5 to 6%) of demineralize water is being added to dilute the water dissolved salt and heated up to 145 Deg C, then it feed to the de-salter system [2]. The de-salter system, separate the water with dissolved salt & sediments (sludge) by providing settling time in the horizontal vessel. The electric current is applied to promote phase separation. De-salted crude oil [3] from top out let of de-salter [2] is going for distillation process and brine water [4] with dissolved salt & sediments drained from bottom of de-salter vessel out let. Small quantity of crude oil also gets carry over with brine water [4]. The quantity of crude oil in brine water depends on multiple factors viz de-salter design, operating parameters, operating condition as well as crude oil quality. The concentration of oil in brine water is found to be in the range of few ppm to 10 % vol. The oil (hydrocarbon) needs to be recollect to save the fuel as well as to minimize losses. Also it is necessary to control ETP operation.

Recollection of oil (Hydrocarbon) from de-salter brine water: According to presnet process explained in figure-1, brine water [4] from de-salter bottom out let send to open pond [5], where floated oily emulsion skimmed off through belt system or suitable system and then skimmed emulsion send to settling tank [8] via pipeline [7] and separated water & sediments from bottom out let [6] send to effluent treatment plant. After 24 to 48 hours of settling time with or without heating treatment, water drained from settling tank [8] bottom out let [9] and oil-in-water emulsion [10] send to ultrasonic treatment system [11].

The quantity of oil-in-water emulsion [10] is very high and the emulsion is mainly having water, heavy hydrocarbon oil, sediments and good amount of undesirable metal elements viz iron, sodium, calcium, magnesium, aluminium, silica, chloride, sulphate etc. as mentioned in Table 1 of summarized test results of experimental study work.

The quantity of oil-in-water emulsion:

The existing process of petroleum refinery is generating oil-in-water emulsion [10] in the range of 0.2 to 1.0 % of its design crude oil throughput. For 20 MMTPA refinery, it is in the range of 40000 to 200000 MT / year.

The present process and technology has limitation to further reduce quantity of oil-in- water emulsion and/or to improve its quality because of very tight emulsion or nature of emulsion.

Oil-in-water emulsion collected after treatment at ETP from de-salter brine water could be either reprocess at refinery or can be disposed of according to legal compliance process. Reprocessing at refinery is a cheap option than any other options.

Due to huge quantity and worst quality of oil-in-water emulsion [10], crude oil refinery facing many problems while reprocessing emulsion even at lower concentration (<1 % ) of crude throughput viz,

1) The huge quantity of emulsion is reducing refining capacity and increasing processing cost hence it has very big financial impact on GRM due to high reprocessing cost (2 to 4 USD / barrel of emulsion), also consume extra energy at different stages, require multiple storage, treatment and handling facilities ( tanks, chemicals, mechanical and heating resources). It has adverse impact on environment as well as it increases hazardous risk. 2) The worst quality of emulsion (high level of water and sediment in tight emulsion form) is destabilize de-salter & CDU operation, generating more slop oil during de-salting process and creating vicious cycle of emulsion.

3) Some time, oil-in-water emulsion generation is very high and it is difficult to manage inventory, hence it become compulsion to reprocess within time frame even at the cost of more CDU throughput loss.

4) It increase fouling, corrosion and frequent breakdown.

5) It also impacting on aviation turbine fuel (ATF) production with respect to deteriorating of ATF colour.

Ultrasonic treatment to reclamation of oil-in-water emulsion:

As explained in Figure 1, oil-in-water emulsion [10] feed to the invented ultrasonic treatment system [11]. The ultrasonic treatment consist of SS tank with required ultrasonic frequency & wattage transducers and stirring/ heating mechanism. The ultrasonic irradiation generates compressions and rarefactions in the oil-in-water emulsion. The compression cycle create a positive pressure on the emulsion by pushing molecules together and the rarefaction cycle create a negative pressure by pushing molecules from each other, ultimately it generates microbubbles, which grown further and collapse down results into shock waves which raise pressure and temperature. The increase of liquid temperature reduces viscosity of emulsion, which helps to mass separation of oil, water, and sediments.

The present ultrasonic treatment tested with 9 litre bath capacity having 37 KHz frequency with 0.5 kilowatt power and also by using pilot plant with 500 liter capacity bath having 27 KHz frequency and 8.4 Kilowatt power. The settling time is studied in the range of 5 to 360 minute. Both the processes viz batch as well as continuous process verified at laboratory scale with various actual samples of oil-in-water emulsion [10] collected at ETP from crude oil de-salter brine water [4].

After ultrasonic treatment [11] with or without chemical diluents and or additives, separated water with sediments drained from bottom out let [12] send to ETP for further process. The top partially reclaimed oily emulsion layer [13] send to centrifuge technique [14] for further quality improvement.

The experimental test results of partially reclaimed oily emulsion [13] are tabulated in Table 1 and indicating that, the ultrasonic treatments is capable to,

A) Reduce up to 65% emulsion quantity B) Separate up to 90% water present in emulsion

C) Separate up to 30% sediments present in emulsion.

Centrifugal Treatment:

As explained in figure 1 the partially reclaimed oily emulsion collected after ultrasonic treatment [11] is mixed with 50% aromatic solvent (toluene or refinery solvent reformate) and feed to centrifugal system [14]. The solvent will reduce density and viscosity of material hence it helps to improve separation of water and sediments using centrifuge process. After centrifugal treatment [14], from bottom [15], separated water & sediments send to ETP and top layer of separated oil [16] send to tank [17] for further settling & reprocessing.

The quality of reclaimed oil is tested at laboratory and test results are tabulated in table 1.

As explained in Figure 1, reclaimed oil with solvent [16] get settling time ( approx. 24 to 48 hour ) at tank [17], after settling, separated water & sediments from bottom out let [18] send to ETP [21] and from top fully reclaimed oil [19] send to refinery for reprocessing. If required, other slop oil generated from refinery [20] can be added into pipeline. Optionally solvent also can be separated by distillation process for reuse. Automatic level control mechanism as well as other atomization can be used for safely operation of process. The refiner can also reprocess partially reclaimed emulsion [13], if quality of emulsion found acceptable.

Experimental Study Work and Test Results:

Various laboratory scale qualitative and quantitative experiments are conducted on actual oil-in-water emulsion collected after treatment at ETP from de-salter brine water are describe below. In this experimental study work following aspects are considered,

1) Development of improved process for reclamation of oil-in-water emulsion collected after treatment at ETP from de-salter brine water to reduce emulsion generation and improve its quality.

2) Experimental work using various irradiation techniques.

3) Experimental work using various chemicals.

4) Experimental work using irradiation combined with different chemicals.

5) Quantification of reclaimed (fully and partially) emulsion, water, and sediments separated from oil-in-water emulsion. 6) Testing of various quality parameters of reclaimed (fully and partially) emulsion, water and sediments separated from oil-in-water emulsion.

7) Laboratory scale experiments with 9 litre capacity US bath.

8) Pilot scale experiments with 500 lit capacity US bath.

9) Feasibility of invented process with respect to cost, availability of technology, operational safety, impact on environment and easy implementation in the field,

Details of equipment and materials used for laboratory experiments:

Ultrasonic Bath:

1) Ultrasonic bath with 9 litre capacity, 37 MHz frequency, and 500 watt power

2) Ultrasonic bath with 500 litre capacity, 27 MHz frequency and 8400 watt power

Laboratory Centrifuge: Design as per ASTM D 4007 test method to check bottom sediments and water (BS&W) with operating parameters viz RPM 2500, time 20 minute and temperature 50 Deg C.

Glass Wares: Bottles (200, 500 and 2000ml capacity), cylinders (100, 500 and 1000ml), separating funnels (100, 250 and 500 ml), test tubes, volumetric flask.

Chemicals / additives: AR grade chemicals viz acetic acid, benzoic acid, citric acid, oxalic acid, Ethylene diamine tetra acetic acid sodium salt and GR grade chemicals viz poly aluminium chloride and aqueous demulsifier.

Solvent for sample preparation: AR grade Toluene, Heptane and refinery aromatic stream (reformate)

Balance for sample weight: 0 to 210 gm and 0 to 5kg.

Filtering Device: 0.2 micron nylon filter paper, 10 ml syringe device and filtration assembly with vacuum pump etc.

Test method used for testing: Water by ASTM D 4006, Sediment by ASTM D 473, BS&W by ASTM D 4007 and metal elements By ICP-OES and aqueous anions by ion chromatography etc. Qualitative Examination 1:

Figure 2 represent the oil-in-water emulsion [10], ultrasonic treated oil [13], reclaimed oil [16] and separated water with sediments [12, 14].

Observations: The white spots in above images indicate the presence of water droplets and black spots indicates the presence of sediment particles. The image a), b) and c) are clearly indicate the reduction of water & sediments and improvement in quality of oil.

Qualitative Examination 2:

Figure 3 representing, Bl is oil-in-water emulsion [10] and B2 the qualitative visual separation of oily layer at top and water with sediments at bottom in laboratory scale batch ultrasonic treatment [11] experiment. The laboratory experiments done using ultrasonic frequency 37 KHz with 0.5 Kw power with 30 minute irradiation time.

Observations: The bottle B2 clearly indicates that after ultrasonic treatment, the water get separated & found to be at bottom layer and separated sediments found to be accumulated at interface level in the water phase.

Summarized Test Results Of Experimental Study Work:

We have carried out multiple laboratory scale and pilot plant experiments and stage wise process improvements & test results are summarized in below Table 1.

Table 1

Observations:

Ultrasonic Treatment:

Various laboratory scale ultrasonic radiation treatment experiments conducted on actual oil-in-water emulsion [10] collected from ETP unit. After ultrasonic radiation treatment, emulsion get partially reclaimed and separated oil & water tested for various quality parameters. The observed test results are highly encouraging and found that invented process is,

1) Improving quality of emulsion (Figure-2, image a and b).

2) Capable to convert oil-in-water emulsion (25% oil + 75% water) into water-in-oil emulsion (75% oil + 25% water).

3) Capable to reduce up to 65 % of emulsion quantity. 4) Capable to separate up to 90% water present in initial emulsion.

5) Capable to remove up to 30 % of sediments present in initial emulsion.

6) Capable to reduce elemental impurities viz iron, calcium, sodium, aluminum, silicon, chloride etc present from emulsion.

7) Observations 1 to 6 are evidence of improvement in quality of emulsion and reduction of emulsion quantity.

Centrifugal Treatment:

Test result obtained from various laboratory scale experiments conducted using solvent dilution & centrifuge treatment on actual partially reclaimed oily emulsion [13] collected after ultrasonic treatment [11] outlet are highly encouraging and found that centrifuge treatment after ultrasonic treatment is.

1) Further improving quality of emulsion (Figure-2, image b and c) are clearly indicates the improvements in quality of oil.

2) Capable to reduce water up to < 1 % vol.

3) Capable to reduce sediments up to < 0.05 % wt.

4) Capable to improve % oil up to 99% vol.

5) Capable to reduce drastically elemental impurities viz iron, calcium, sodium, aluminium, silicon, chloride etc. present after ultrasonic treatment.

6) Observations 1 to 5 are evidence of further improvement in quality of oil and reduction of emulsion quantity.

Conclusions:

Based on test results of various laboratory experiments and observations of invented ultrasonic process followed by addition of solvent & centrifuging treatment for reclamation of oil-in-water emulsion collected after treatment at ETP from crude oil desalter brine water, we conclude as follow:

1) Invented process is capable to convert oil-in-water emulsion into good quality of oil (99% oil + <1.0% water + < 0.05% sediments).

2) The reclaimed oil (partially or fully) can be easy to reprocess with crude oil.

3) Invented process is capable to reduce up to 65 % volume of emulsion quantity after first stage and up to 74% volume after second stage.

4) Invented process is capable to separate up to 99% volume water present in emulsion after second stage.

5) Invented process is capable to reduce sediments up to <0.05 % wt. level. 6) Invented process is capable to reduce undesirable elemental impurities > 90 % viz iron, calcium, sodium, aluminum, silicon, chloride etc. present in emulsion.

7) Invented process has removed water, sediments, elemental impurities hence is capable to improve quality of emulsion which is also evident in density of emulsion.

8) Invented process is reducing significant amount of emulsion quantity and improving quality of emulsion, hence it will help to resolve following problems experienced by petroleum refinery due to huge quantity as well as worst quality of emulsion viz. a) The reduced emulsion quantity will allow refinery to process more crude oil as well as avoid reprocessing cost, hence will lead to earn more profit. Also it will reduce energy consumption at different stages, reduce facility requirements for storage, treatment and handling (tanks, chemicals, mechanical and heating resources) of emulsion. It will additionally reduce impact on environment and hazardous risk. b) The improved quality of emulsion will reduce operational problems (destabilization) at crude oil distillation & de-salter unit and improve de-salter efficiency. It will help to breaking of vicious cycle of emulsion. c) It will reduce fouling, corrosion and frequent breakdown. d) It will reduce impact on ATF colour.

Pilot Skid Batch Process Trial:

Pilot skid was installed with three-meter cube feed tank for oil in water emulsion also called slop oil near R&D laboratory for batch process trials. As and when required, slop oil was transported using gulley sucker from ETP Tank-C / B which is collected from desalter brine water and unload into feed tank. Various trials were conducted for process optimization and performance verification. The performance test results after optimization are tabulated in below table-2

Table-2

Observations:

Following are the observations derived from the test results of batch process trial,

1) Pilot skid trial has demonstrated average 63% reduction of slop oil quantity at 120 min irradiation time and highest reduction achieved up to 73 %.

2) Pilot skid trial has demonstrated average water separation efficiency 84 percentage which is close to the laboratory scale experiments done using small capacity ultrasonic bath and highest water separation achieved up to 94 %.

3) Pilot skid trial has demonstrated average sediments removal 35 percentage which is close to the laboratory scale experiments done using small capacity ultrasonic bath and highest sediment removal achieved up to 49 %.

4) Pilot skid performance was verified & optimized for irradiation time and stirring effects.

Pilot Skid Continuous Process Trial:

After verifying batch process performance at R&D laboratory, the performance of invented process discussed with concern officials of operation and technical service department to conduct continuous process trail at ETP to verify the performance at field. The pilot skid was shifted to effluent treatment plant (ETP) for field trial using continues process. The feed emulsion arrangement done from ETP slop oil tank A & B after settling and separated oil & water connected to ETP feed sump. Separated water and oil flow was manually measured during trials and used for performance calculation. All plant safety SOPs were followed during trails.

ETP operation team has conducted various field trials (total 83 running hours) with continuous process with variable parameters to check the performance as well as optimize operation parameters viz feed flow rate, effect of irradiation time, process temperature, effect of stirring, effect of interface level etc. Also required samples (feed slop oil and separated oil & water) were collected & tested at laboratory to evaluate performance of invented process. Performance test results after optimization are tabulated in below table 3. Table-3

Observations:

Following are the observations derived from the test results of continuous process field trial,

1) Pilot skid trial has demonstrated average 45% reduction of slop oil quantity and highest reduction achieved up to 50 %.

2) Pilot skid trial has demonstrated average water separation efficiency percentage slight lower than past experiments and highest water separation achieved up to 74 %.

3) Pilot skid trial has demonstrated average sediments removal percentage close to the past experiments and highest sediments removal achieved up to 34 %.

4) Pilot skid operated with continuous process in the range of 0.6 to 1.8 meter cube per hour and observed highest 0.8 meter cube per hour water separation.

5) Skid was continuously operated up to 10 hours to see the performance of system and found to be satisfactory.

6) Skid performance was verified & optimized for stirring and temperature effect.

Conclusions:

Based on test results of both (batch and continuous process) trials observations, it is concluded as below,

1) Pilot skid performance in batch trial at Lab and continuous process at field trial is found to be satisfactory and close to the expectations.

2) Pilot skid is reducing slop oil generation up to 50% volume in continuous process and up to 70% in batch process. ) Pilot skid is removing sediments up to 34% in continuous process and up to 49% in batch process. ) Invented process is removing water, dissolved salt and sediments from ETP slop oil hence it is improving the quality of slop oil.

Pilot skid trials performance data will be highly useful to design large scale design to achieve similar performance and conduct further R & D work to improve the performance.

Advantages of the invention:

The present invention is globally applicable to crude oil petroleum refinery. The present invention is capable to convert oil in water emulsion to good quality oil and has many benefits to crude oil refining industries viz.,

Based on test results of various laboratory experiments and observations of invented process for reclamation of oil-in-water emulsion collected at ETP from crude oil de-salter brine water using ultrasonic irradiation treatment followed by addition of solvent & centrifuging, we envisaged advantages are as follow:

1) Invented process will convert oil-in-water emulsion into good quality of oil (99% oil + <1.0% water + < 0.05% sediments).

2) The reclaimed oil (partially or fully) will be easy to reprocess with crude oil.

3) Invented process will separate up to 90% water at first stage and up to 99% volume of water present in emulsion after second stage.

4) Invented process will reduce sediments up to <0.05 % wt. level.

5) Invented process will reduce undesirable elemental impurities > 90 % viz iron, calcium, sodium, aluminum, silicon, chloride etc. present in emulsion.

6) Invented process will remove water, sediments, elemental impurities hence it will improve quality of emulsion.

7) Low cost solution and technology easily available in the market.

8) It is safe to operate in the field.

9) Invented process will reduce significant amount of emulsion quantity and improve quality of emulsion hence it will help to resolve following problems experienced by petroleum refiner due to huge quantity as well as worst quality of emulsion viz. a) The reduced emulsion quantity will allow refiner to process more crude oil as well as avoid reprocessing cost, hence will lead to earn more profit. Also it will reduce energy consumption at different stages, reduce facility requirements for storage, treatment and handling (tanks, chemicals, mechanical and heating resources) of emulsion. It will additionally reduce impact on environment and hazardous risk. b) The improved quality of emulsion will reduce operational problems (destabilization) at crude oil distillation & de-salter unit and improve de-salter efficiency. It will help to break vicious cycle of emulsion. c) It will reduce fouling, corrosion and frequent breakdown. d) It will reduce impact on ATF colour.

The invented process is having high returns on investment and easy to implement in the field hence it will give huge benefits to the refiner globally.

Although the invention has been described with reference to specific embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternate embodiments of the invention, will become apparent to persons skilled in the art upon reference to the description of the invention. It is therefore contemplated that such modifications can be made without departing from the spirit or scope of the present invention as defined.