TKACHOU, Siarhei (Shkolnaya 24-23, 0 Novopolotsk, 21144, BY)
CHYKUN, Ihar (Komsomolskaya 13-121, 0 Novopolotsk, 21144, BY)
YAHUDZIN, Rustam (Sverslova 25-52, 0 Polotsk, 21144, BY)
VALOCHNIK, Aliaksey (Komsomolskaya 18-813, 0 Novopolotsk, 21144, BY)
TKACHOU, Siarhei (Shkolnaya 24-23, 0 Novopolotsk, 21144, BY)
CHYKUN, Ihar (Komsomolskaya 13-121, 0 Novopolotsk, 21144, BY)
YAHUDZIN, Rustam (Sverslova 25-52, 0 Polotsk, 21144, BY)
| The Claims 1. A method of an oil residue utilization comprising treatment of said oil residue by an aqueous-hydrocarbon emulsion system followed by setting and separation into respectively aqueous, hydrocarbon and solid phases, pumping out said aqueous phase and recycling said hydrocarbon phase with said aqueous- hydrocarbon emulsion system containing an aqueous solution of liquid glass as a chemical agent disintegrating said oil residue structure and a hydrocarbon base, wherein said hydrocarbon base presents oil having the following ratio of components oil - from 1 to 10 parts in volume a chemical agent -1 part in volume, while said chemical agent presents a solution of liquid glass in D.C. -activated water having pH=9-12 with the following ratio of components: liquid glass from 0,3 to 25% D.C.-activated water the rest up to 100%. 2. A method as in claim 1, wherein said treatment is performed at the temperature >0°. 3. A method as in claim 1, wherein said treatment is provided by supplying a chemical agent under an oil level without any falling jets. 4. A chemical agent for destroying an oil residue structure presenting an aqueous solution of liquid glass, wherein said chemical agent presents a solution of liquid glass in D.C.-activated water having pH=9-12 with the following ratio of components in weight %: liquid glass - from 0,3 to 25%, D.C.-activated water - the rest up to 100%. 5. A chemical agent as in claim 4, wherein said chemical agent additionally contains a surface-active substance (SAS) chosen from the group including: sintanol, oxyethylated butyl alcohol, sodium salt, alkylbenzolsulphonic acids, sintamide-5, OC-20 with the following ratio of components, weight %: liquid glass - from 0,3 to 25%, SAS - from 0,2 to 10% D.C. -activated water - the rest up to 100%. |
Field of the Invention
The invention is related to the field of oil-producing and oil-refining industry and, in particular, to the utilization methods of oil residue formed at the oil gathering-and-treating terminals and accumulated in the oil removers, earthen containers, reservoirs and setting vessels.
Background of the Invention
Known is an oil residue utilization method [Russian Federation Patent RU2064962, published 1996.08.10] which consists in that an oil residue is pre- mixed with oil in a mass ratio of 1 : (2-4), and an oil layer received as a result of filtration and setting of said mixture of an oil residue with oil is proportioned as stock-tank oil in such quantities that the content of permissible impurities in said stock-tank oil would not exceed the tolerable standards.
The disadvantage of the above method is that separated mechanical impurities of an oil residue are greatly contaminated by oil, which requires their additional after-treatment.
Another well-known prior art example is a method of cleaning an oil reservoir by washing jets of a cleansing agent with a subsequent recovery and re-use of said cleansing agent which is an aqueous emulsion disperse system spontaneously formed during mixing in equal volumes of 0,5 to 2,0% aqueous solution of liquid glass (alkali silicate) and of 1,0% hydrocarbon solution of nonionic surface-active substance (SAS) characterized by its enhanced rinsing and demulsifying properties, e.g. neonol AF 9-J2 wherein aromatic hydrocarbon solvents such as toluene are used as a hydrocarbon solvent which are characterized by their high solvent ability in relation to asphalt-sludgy-paraffin deposits [Russian Federation Patent 2002114567, published 2004.01.20]. Washing of the reservoir walls and of its bottom portion by the cleansing agent jets is conducted at the minimum environmental temperature of O 0 C. A waste cleansing agent is further separated into the three phases i.e. a hydrocarbon phase, a solid phase and an aqueous solution of liquid glass and neonol AF 9-I2 .
The basic disadvantage of the above method is a high cost of a hydrocarbon solvent.
The nearest prior art reference is US patent 5858247, published January 12, 1999 which describes the use of cleansing agents having different compositions (comprising also an aqueous solution of liquid glass as active components) which are injected through a number of movable nozzles positioned downwardly from a reservoir top portion along the reservoir cargo and drain pipes that are to be cleaned. The disadvantage of this method is a high cost of chemical agents and its low efficiency.
Known are cleansing agents for removing oil impurities and asphalt- sludgy-paraffm deposits from metal surfaces "TEMP-100D" [USSR Author's Certificate 973607, Int. Cl. CI lD 1/83, 1980] and a cleansing agent "OSA" [USSR Author's Certificate 1004466, Int. Cl. CI lD 1/83, 1981] which are used as 0,5-2% solutions and contain nonionic surface-active substances, sodium metasilicate, di-or-trisodium phosphate, soda ash and a small amount of potassium salt of oxyethylated alkyl phenols of phosphoric acid.
Also known is an industrial cleansing agent for removing fatty and oil contamination from metal surfaces [Russian Federation Patent 2194748, published 2001.12.20]. This agent is used in the form of a 0,5-2% solution and contains neonol AF 9-12 as a SAS in the following amount, weight %: neonol AF 9-I2 from 2,4 to 3,6 neonol AF 6-9 from 2,4 to 3,6
Sodium salt of alkylbenzolsulphonic acids (sulphonol) from 0,4 to 0,6 The above-mentioned cleansing agent additionally contains, weight %: soda ash from 51 ,0 to 64,0; sodium tripolyphosphate from 13,0 to 28,0; trisodiumphosphate from 13,0 to 17,0.
The basic disadvantage of the above-mentioned cleansing agents is their low washing ability and also a large content of detrimental compounds which when present in wastewater are harmful for the environment.
As for the chemical agent the nearest prior art reference is a chemical agent C- 105 BC for dilution and removing of an oil residue [US Patent 5,858,247 January 12, 1999]. This agent contains, weight %: sodium silicate (liquid glass) 5, butyl ether of ethylene glycol or polyethylene glycol 5, water 90.
The basic disadvantage of this cleansing agent is its low reaction ability, which results in the increase of the cleansing time.
Summary of the Invention
It is the aim of the present invention to provide an inexpensive and efficient utilization of an oil residue formed at the oil gathering-and-treating terminals and accumulated at the oil removers, earthen containers, reservoirs and setting vessels by means of recovery of said oil residue.
This aim is achieved by the dilution of an oil residue (at the minimum environmental temperature of O 0 C) with an aqueous-hydrocarbon emulsion system produced by mixing oil with a chemical agent in the following ratio: oil - from 1 to 10 parts in volume chemical agent -1 part in volume, while said chemical agent presents a solution of liquid glass in D.C.- activated water having pH=9-12 with the following ratio of components: liquid glass from 0,3 to 25%
D.C. -activated water having pH=9-12 - the rest up to 100%. This makes it possible to recycle up to 90% of an oil residue as recovered oil.
This aim is achieved by a chemical agent for disintegration of an oil residue structure, said agent presenting an aqueous solution of liquid glass in D.C. -activated water having pH=9-12 with the following ratio of components: liquid glass from 0,3 to 25%
D.C. -activated water having pH=9- 12 - the rest up to 100%..
D.C. -activated water is produced by D.C. current treatment of water under conditions that eliminate any possibility of mixing between an alkaline (anode) part and an acidic (cathode) one, e.g. by means of installing a semi-impermeable partition between anode and cathode as it is described, for example, in a USSR Author's Certificate SU1261904, published 1986.10.07.
To more efficiently remove oil contamination containing large amounts of paraffin (>35%) a chemical agent in question also contains SAS chosen from the group including: sintanol, oxyethylated butyl alcohol, sodium salt, alkylbenzolsulphonic acids, sintamide-5, OC-20 with the following ratio of components, weight %: liquid glass from 0,3 to 25
SAS from 0,01 to 10
D.C. -activated water having pH=9- 12 - the rest up to 100%.
The use of SAS facilitates disintegration of paraffin structures and the conversion of contamination into a mobile emulsion.
A method is based on the processes of softening, dilution and demulsification of an oil residue. The treatment of an oil residue is performed by means of a highly efficient recycling of an oil residue inside a reservoir being cleaned.
After recycling and setting in a reservoir being cleaned a newly formed disperse system under the influence of chemical agents and gravitation is separated into a hydrocarbon fraction (an oil layer), water and mechanical impurities. An oil residue is proportioned as stock-tank oil under a rigid control of a water content, while a water layer and mechanical impurities are further utilized.
The method makes it possible to separate from an oil residue a hydrocarbon phase which is characterized by a low content of water and mechanical impurities. High quality of a hydrocarbon phase makes it possible without any additional pre-treatment to directly mix it with a stock-tank oil having a quality margin which results in an oil meeting the market standards. A hydrocarbon phase could undergo further treatment to meet the market standards by means of an oil treatment apparatus or it could be used and marketed without any additional treatment as a furnace fuel or a mixture of waste oil products.
No expensive equipment for the mechanical separation of an oil residue such as centrifuges, decanters etc. is required.
Short Description of the Drawings
Figure 1 illustrates the comparison between the recovery values of an oil residue respectively for a chemical agent claimed and a number of prior art diluent compositions.
Figure 2 illustrates the comparison of the residual water content in an oil layer respectively for a chemical agent claimed and a number of prior art diluent compositions.
Data Confirming Implementation Possibility
A method claimed could be implemented in the following way.
A chemical agent claimed is prepared by mixing liquid glass with D.C.- activated water having pH=9-12 according to the proportion as claimed. If an oil residue to be utilized has a high paraffin content a chemical agent could be added with from O 5 OHo 10% of SAS chosen from the group including: sintanol, oxyethylated butyl alcohol, sodium salt, alkylbenzolsulphonic acids, sintamide- 5, OC-20.
Oil in a volume from 20 to 150% in proportion to an oil residue volume is injected into a reservoir to be cleaned and then a chemical agent in a volume from 10 to 15% in proportion to an oil residue volume is supplied. A chemical agent is preferably supplied into a reservoir just under an oil level with no jets falling, this substantially eliminating any risks of static electricity generation and improving fire-and-implosion safety.
Recycling is performed by means of a powerful rotary pump and a system of nozzles. A recycled emulsion is pumped out through a reservoir sump and returned to a reservoir through special nozzles located either on a pontoon or a reservoir cover. Should it be necessary an oil residue recycling could be performed by any other method e.g. by means of mixers. Recycling continues until a complete dilution of an oil residue and its conversion into a disperse system is achieved.
After recycling and setting in a reservoir being cleaned a disperse system under the influence of chemical agents and gravitation is separated into a hydrocarbon fraction (an oil layer), water and mechanical impurities.
An oil residue is proportioned as stock-tank oil under a rigid control of a water content, while a water layer and mechanical impurities are further utilized.
The water which is pumped out and which contains a basic amount of waste chemical agents is further supplied to the treating facilities or is cleaned by means of a mobile apparatus for treatment of oil-containing water. Due to the fact that the chemical agents claimed are used in low concentration (up to 0,5% in proportion to an oil residue volume) and when present in the air environment and wastewater said chemical agents do not form any toxic compounds, no special methods for sanitation and cancellation of said chemical agents are required.
After pumping out of hydrocarbon and water fractions a degassing procedure is performed in the following way. A face team enters a reservoir and by means for example of a hydraulic-driven sinking pump and water jets from the hand fire nozzles removes the residual mechanical impurities from a reservoir into an intermediate setting tank. After setting the water is supplied for purification, while the mechanical impurities are dehydrated (by means of band filter press or other equipment) and utilized in accordance with the customer's requirements.
An oil residue treatment as claimed is performed throughout the reservoir being cleaned which substantially decreases cleaning time. A complete cleaning of a reservoir RVS50000 containing a large volume of an oil residue can be performed during from 20 to 30 days.
The above described utilization method makes it possible to provide the refinement of almost the whole of an oil residue hydrocarbon portion in the form of recovered oil which could make up over 90% of said oil residue weight.
The efficiency of a method filed and that of a chemical agent used for an oil residue recovery was studied by way of comparison. The following three diluent compositions were taken as the base for comparison
1. Chemical agent C- 105 (Texchem USA)
2. A diluent composition spontaneously formed during mixing in equal volumes of 1,0% aqueous solution of liquid glass and of 1,0% hydrocarbon solution of nonionic surface-active substance (SAS) i.e. neonol AF 9-12 wherein an aromatic hydrocarbon solvent is used as a hydrocarbon solvent [see Russian Federation Patent application 2002114567]
3. A diluent composition presenting a trolly system according to claim 1 , wherein a chemical agent according to claim 4 of the present invention is used.
The study involved 4 kinds of an oil residue each having the following properties: Table 1 Properties of Oil Residue Samples
The study was performed in the following way: an oil residue sample in the volume of 5 1 was put into a reservoir. Said sample was diluted with a respective diluent composition in the volume of 2,5 1 with a liquid upper layer further subjected to a recycling by means of a pump having the speed of a volume supply of 0,3 1/sec. A jet was supplied into the center of the reservoir. In 12 minutes the recycling was stopped, a liquid layer was discharged and the remaining oil residue measured. The data received as a result of an experiment are illustrated in Table 2.
Table 2 - Oil Residue Recovery Value (%):
A Recovery value (RV) was calculated according to the following formula:
V\ - V2
RYCB = -100%
Fl
Where RV is an oil residue recovery value
Vl is an oil residue volume before the experiment
V2 is an oil residue volume after the experiment
As it is evident from the diagram in Fig. 1 a method and a chemical agent claimed are characterized by a higher recovery value as compared to similar characteristics of the samples No. 1, 2, and 4. The efficiency of a composition No. 3 in sample No. 3 is somewhat lower as compared to the composition No. 2, which can be explained by a high content of paraffin hydrocarbons.
One of the most important characteristics of a recovered oil residue is a residual water content. To define this value a liquid phase received in the previous experiment was subjected to setting for 24 hrs with further analysis of a water content in an oil layer according to Dyne- Stark method. The analysis data are given in Table 3.
Table 3. Water Content in Oil Layer, %:
As it is seen from the analysis data a residual water content in an oil layer of compositions 1 and 2 is substantially higher, which can be explained by the formation of stable emulsions due to the use of SAS in said emulsions.
Implementation Examples
Example 1:
Customer: NRUPTN "Druzhba", Belarus
Reservoir: PBC 50000 with a floating cover for crude oil storage
Oil residue volume: 7260 M3
Cleaning duration: 20 days
Deposit accumulation term over 20 years (deposits were collected from other reservoirs after cleaning thereof by using traditional methods).
Recycling of an oil residue was performed for 10 days by means of a rotary pump and a system of nozzles through a floating reservoir cover. The positioning of said nozzles and their sloping angles were varied several times a day. The measurements of an oil residue level were conducted daily. After recycling and a short-term setting the reservoir content was separated into a hydrocarbon phase, water and mechanical impurities.
An independent supervision company SGS conducted sampling of a hydrocarbon phase separated from an oil residue to check its correspondence to State Standard Specification GOST P 51858-2002. According to the analysis data the quality of a recovered oil product corresponded to that of stock-tank oil.
A recovered oil product was pumped into a pipe-line and water was supplied into a treating facility. Mechanical impurities were removed from a reservoir by means of pressurized water.
As a result it took 20 days to clean a reservoir, while over 7000m 3 of an oil residue were removed and over 5000m 3 of oil suitable for treatment were extracted from the latter.
Example 2.
Customer: "Narjanmarnephtegas", Varandej, Russia
Reservoir: RVS 10000 for crude oil storage
Oil residue volume: 500 m 3
Cleaning duration: 10 days
The calculated amounts of the emulsion pre-treated according to the present invention were pumped into a reservoir containing an oil residue. Recycling of the reservoir content was made by means of a mixer Diogen 500 which was installed in the reservoir for this purpose. After 3 days of the mixer operation the whole of the oil residue was transformed into a liquid state and pumped into another reservoir. The remains of the oil residue were vacuum- pumped out. As a result of cleaning over 450m 3 of oil suitable for treatment were extracted from the oil residue.