MX2010000765A - Process for treating wastewater and/or oily water. - Google Patents

Abstract

The present invention is related to a process for treating wastewater and/or oily water resulting from the dehydrating and desalting processes of crude petroleum oils, either from refineries or plants for dehydrating crude petroleum oil resulting from the exploitation and production areas, such as the CAB in Cunduacán, CAB in Samaria and the TMDB in Paraiso, Tabasco; so as to be dislodged to the sea within the limits established by the current environmental policies, which establish a maximum content of oil and grease of 15 to 25 ppm. The process of the present invention includes an absorber additive comprising a mixture of halogen products, agents of active surface with non-ionic character and agents of active surface with anionic or cationic character; this mixture of chemical reactants presents properties of absorption, dilution and active surface required for treating wastewaters and/or oily waters resulting from the dehydrating and desalting process of crude petroleum oil. The pr ocess of the present invention uses an absorption tower including the absorber additive therein, which may remove the hydrocarbons from the oily water until the content of oil in the absorber is of from about 30% to 40% per volume, then the absorber being regenerated by a superficial heating at a temperature of from about 60°C to about 70°C; the vapours emitted by this regeneration are received in a condenser and the oil extracted from the oily water is integrated to the crude oil stream of the installation.

Description

PROCESS OF TREATMENT OF RESIDUAL AGUAS AND / OR OILS DESCRIPTION TECHNICAL FIELD OF THE INVENTION The present invention relates to a process for the treatment of wastewater and / or oily water coming mainly from the processes of dehydration and desalination of crude oil oils, both refineries and dehydrated plants of crude oil from the exploitation area. and Production, for their eviction to the sea within the limits established by the current environmental legislation, which in this regard establishes a maximum content of fats and oils of 15 to 25 ppm.

BACKGROUND OF THE INVENTION For the disposal of the residual water product of the dehydration of the crude petroleum oil that is delivered to refineries or sent to Export, it is necessary to comply with the Official Mexican Standard NOM-001-ECOL-1996 that establishes the permissible limits of contaminants in the discharges of wastewater in waters and national goods, among other specifications, a maximum discharge temperature of 40 ° C and a maximum content of fats and oils of 15 to 25 mg / liter is determined.

The traditional methods of treatment of these wastewater consist of breaking the so-called "reverse" emulsions, which refer to "oil in water" emulsions, by the use of a demulsifying agent, which is composed of: tense-active agent - coalescer, a deparaffinizer, an esterifier and an aromatic solvent as a vehicle (Xylene); Therefore, it has become necessary to develop a series of chemical reagents that help the separation and / or recovery of the oil contained in this water.

These traditional treatments in addition to requiring the continuous dosing of the demulsifying agent, demand of tanks or storage pools where the necessary residence time is given for the reagents to "work" by wetting the emulsion and solving it, these pools also provide the necessary time to that the water cools to the limits indicated in the Official Standard referred to (40 ° C).

The present invention provides a highly advantageous alternative over traditional methods of wastewater treatment, since it does not require the injection of additives and only requires a minimum contact time of one minute between waste water and an absorber additive to extract the hydrocarbons that are contained in oily waters.

It is therefore an object of the present invention to provide a process for the treatment of wastewater and / or oily originating mainly from the processes of dehydration and desalination of crude oil oils, both refineries and dehydrating plants for crude oil oil. of the Exploitation and Production area, for its eviction to the sea within the limits established by the current environmental legislation, which in this respect establishes a maximum content of fats and oils of 15 to 25 ppm.

A further object of the present invention is to provide a process for the treatment of waste and / or oily water, comprising an absorption tower containing an absorbing additive, to remove hydrocarbons from oily water when it passes through the absorbing reagent, in a time not less than a minute of contact.

Still another object of the present invention is to provide a process for the treatment of waste and / or oily water, which employs an absorbing reagent which is composed of a mixture of halogenated compounds, surface active agents with a non-ionic character and surface agents. active anionic or cationic character.

BRIEF DESCRIPTION OF THE DIESES OF THE I NVENTION Figure 1 is a diagram of the process for the treatment of waste and / or oily waters of the present invention, where: P1 = Inlet current of residual and / or oily water to be treated; P2 = Absorbent additive stream saturated with fats and oils to Reheater, for regeneration of the absorbent; P3 = Hot stream of absorbent additive, fats and oils a Pump, for regeneration of the absorbent; P4 = Hot stream of absorbent additive, fats and oils to Absorber Tower, for regeneration of the absorbent; P5 = Water outlet current, with maximum fats and oils content from 15 to 25 ppm; P6 = Current of absorbent additive to Condenser, for regeneration of the absorbent; P7 = Current of absorbent additive to Separator, for regeneration of the absorbent; P8 = Reflux current of the absorbent additive, during its regeneration; P9 = Obtaining the regenerated absorbent additive, for its reuse; Y P10 = Purge fats and oils extracted from water.

Figure 2 shows a typical distillation curve of the absorber, which distills at a maximum temperature of 70 ° C, so that its regeneration is simple and economical.

DESCRIPTION OF THE INVENTION The present invention relates to a process for the treatment of wastewater and / or oily originating mainly from the processes of dehydration and desalination of crude oil oils, both refineries and dehydrating oil crude oil plants in the Exploitation area and Production, for its eviction to the sea within the limits established by the current environmental legislation, which in this respect establishes a maximum content of fats and oils of 15 to 25 ppm.

The process of the present invention, according to Figure 1, consists of: 1. Feed residual and / or oily water to be treated (P1) to the bottom of the Absorber Tower and pass it through the Packed Section containing the Absorbent Additive to eliminate the maximum content of fat and / or oil, this path must be done in a minimum time of one minute, to eliminate the maximum content of fat and / or oil; 2. To recover the treated water (P5), with a maximum content of fats and oils from 15 to 25 ppm, and 3. Regenerate the Absorbent Additive saturated with fats and oils (P2), by: a. Heating in a Reheater (P3) b. Pumping to the Absorber Tower (P4) c. Cooling (P6) d. Separation of the absorbent additive (P8 and P9) 4. The fats and oils extracted from the water, at a boiling temperature higher than 70 ° C, remain at the bottom of the Absorber Tower (P10), from where they are extracted by means of a purge that is carried out once the regeneration of the absorbent is completed.

The Absorber Tower that contains the absorber additive will allow to have a contact time of residual water and / or oily - absorber additive minimum of one minute, to eliminate the maximum content of fat and / or oil.

This extraction-absorption will continue with high efficiency until the Absorber Additive has been "saturated" with hydrocarbons which means a content of 30 to 40% volume, after which it will be necessary to regenerate it; for this the injection of water in the Absorber Tower is suspended and the Reheater of the bottom of the Absorber Tower is turned on; When the solution is heated to 60-70 ° C, the Absorber Additive will evaporate, the recirculation of the bottom of the Absorber Tower is maintained through the Reheater; The Absorber Additive will reach the dome and pass to the Condenser, where it will condense and pass to a Separator, while the extracted fats and oils will be integrated to the crude oil flow of the installation; once the distillation is done and taking care that the absorbing additive does not stain fats and oils; This is achieved by taking care that the temperature of the dome does not exceed 70 ° C. The process can be continuous if there is another Absorber Tower as described.

The condenser must cool the vapors of the regenerated additive from 70 to 40 ° C, temperature at which the vapors of the Absorbent Additive are condensed. Under this scheme, the additive will be in a position to be reused.

The Absorber Additive used for the removal of hydrocarbons from oily water from the process of dehydration and desalination of crude oil oils, has the following formulation: 80 to 90% weight of one or more halogenated compounds, such as methylene chloride, dichloroethane , Trichloroethane, 1,3-Chloro-butadiene and Trichloromethane; 2 to 5% by weight of an active surface agent with a non-ionic character of the "Tetronic®" type, of the general formula Amina with ethylene oxides and propylene oxides; and 2 to 5% by weight of an active surface agent: of an anionic character such as sodium lauryl sulfate, or of a cationic nature which can be a quaternary ammonium derivative, possessing emulsifying, detersive and degreasing properties.

The procedure by which the Absorber Admixture used for the removal of hydrocarbons in oily water is obtained comprises the following steps: the halogenated compounds are placed in a vessel equipped with stirring agents, the active surface agent is then added in a non-toxic manner. ion and finally the active surface agent with wetting properties is added, it is stirred homogeneously for a period of 60 minutes until the complete dilution of the surfactants and the agitation is continued until a perfectly homogeneous mixture of the components is achieved.

To check the homogeneity of the product, a sample is taken from the dome and another from the bottom of the container and the viscosity and the specific weight of both are determined at 20/4 ° C, when the values are equal, agitation is stopped, under these conditions of processing, a transparent liquid is obtained, more dense than water, it is not flammable; Other properties are: Specific Weight @ 20/4: Water content,% volume Viscosity, Cp: Boiling temperature, ° C: To carry out the laboratory evaluation of the absorption capacity that the Absorber Additive has, laboratory tests were made using solutions of the absorber additive which contained 5, 10, 15, 20, 25 and 30% volume of crude oil; the test consisted of passing through the solutions of the absorbing agent, oily water containing 100 ppm of fats and oils, this water was passed through the solutions mentioned with a contact time of one minute, the "filtered" water had to have less than 5 ppm of fats and oils.

Some practical examples are described below to have a better understanding of the present invention, without this limiting its scope.

Example 1 To evaluate the efficiency of the absorber additive tests were performed in the laboratory, using the described test method, obtaining the following results: In order to determine the content of fats and oil in the Absorber Additive at any time, it is recommended to make a distillation, up to 70 ° C. The percentage of fats and oils contained in the absorbent agent is determined by the following formula: A x 100 % fat and oil volume = (B - A) where: A = Volume of fat and oil recovered B = Total volume of the sample Example 2 When the Absorber Additive has become saturated with the fats and oils that have been extracted from the oily water, it is necessary to regenerate it, which is carried out by means of a distillation, heating up to a temperature of 70 ° C; It is not advisable to increase the temperature further because there is a risk of evaporating the hydrocarbons extracted from the oily water (Figure 2).

In order to verify the quality with which the Absorber Additive is regenerated, dilutions must be made with the Absorber Additive containing different amounts of the fats and oils that the oily water has. The dilution scale ranges from 10 to 100 ppm. The regenerated Absorber Additive must be of an intermediate color of this scale; that is to say, the regenerated Absorber Additive must have a maximum content of 100 ppm in order to preserve intact the qualities that the Absorber Additive has for this patent.

Claims (10)

NOVELTY OF THE I NVENTION What is claimed is:

1. A process for the treatment of wastewater and / or oily originating mainly from the processes of dehydration and desalination of crude oil oils, which consists of: a) Feed residual and / or oily water to be treated (P1) to the bottom of the Absorber Tower and pass it through the Package Section containing the Absorbent Additive to eliminate the maximum content of fat and / or oil; b) Recover the treated water through the dome (P5); c) Regenerate the Absorbent Additive saturated with fats and oils (P2), by: i. Heating in a Reheater (P3), ii. Pumping to the Absorber Tower (P4), iii. Cooling (P6), and iv. Separation of the absorbent additive (P8 and P9); Y d) Removal of fats and oils extracted from water (P10), at a boiling point higher than 70 ° C, to obtain a water treated with a maximum content of fats and oils of 15 to 25 ppm.

2. A process for the treatment of waste and / or oily water in accordance with clause 1, where the passage of waste and / or oily water through the Packed Section must be done in a minimum time of one minute.

3. A process for the treatment of waste and / or oily water in accordance with clauses 1 and 2, where the Packed Section employs an Absorber Additive that has the following formulation: 80 to 90% by weight of one or more halogenated compounds; 2 to 5% weight of an active surface agent with non-ionic character; and 2 to 5% weight of an active surface agent of anionic or cationic character.

4. A process for the treatment of waste and / or oily water in accordance with clauses 1 to 3, where the halogenated compounds of the Absorber Adsorbent are preferably Methylene Chloride, Dichloroethane, Trichloroethane, 1,3-Chloro-Butadiene and Trichloromethane.

5. A process for the treatment of waste and / or oily water in accordance with clauses 1 to 4, where the active surface agent of non-ionic character of the Absorber Additive is preferably of the "Tetronic®" type, of the general formula Amina with oxides of ethylene and propylene oxides.

6. A process for the treatment of waste and / or oily waters according to clauses 1 to 5, wherein the active surface agent of anionic character of the Absorber Additive is preferably sodium lauryl sulfate.

7. A process for the treatment of waste and / or oily water in accordance with clauses 1 to 6, wherein the cationic active surface agent of the Absorber Additive is preferably a quaternary ammonium derivative.

8. A process for the treatment of waste and / or oily water in accordance with clauses 1 to 7, where the regeneration of the Absorbent Additive is carried out when the Absorber Additive is saturated with hydrocarbons with a minimum content of 30 to 40% volume.

9. A process for the treatment of waste and / or oily water in accordance with clauses 1 to 8, where the Reheater operates at a temperature of 60 to 70 ° C.

10. A process for the treatment of wastewater and / or oily in accordance with clauses 1 to 9, where the condenser cools the vapors of the Regenerated Additive from 70 to 40 ° C.