RU2247232C2 - Method for processing water for extraction of oil by thermal methods - Google Patents

Abstract

FIELD: oil extractive industry.

SUBSTANCE: method includes first stages of capturing energy of processed heat from high pressure steam separator, placed below steam generators. Then transfer of heat energy into heated separator and evaporator and heat exchanger is performed for distillation of bed water present in oil-bearing bed and restoration of distillated water and concentrated salt solution or hard product. Concentrated water steam from heated separator is circulated through evaporator and heat exchanger to support from 1% to around 50% of steam mass in the flow, returning into heated separator, and prevent pollution and forming of scale. Equipment includes separator for processed low pressure energy, heated separator and steam compression with forced circulation circuit to produce distillated water.

EFFECT: higher efficiency.

6 cl, 2 ex, 1 tbl, 13 dwg

Description

The present invention relates to a highly efficient method for distillation of water and an apparatus for this method, and more specifically, the present invention relates to a highly efficient method for distillation of water used for the extraction of crude oil by thermal methods, which provides minimal clogging and scale formation in working equipment for a long period work.

In various regions of the world, the extraction of crude oil, a hydrocarbon material having a significantly higher viscosity or a lower density measured in degrees from the American Petroleum Institute (ANI) (less than 20 ° ANI, typically 7-12 ° ANI), than that of traditional petroleum feedstocks, It is more labor-intensive and requires increased thermal stimulation of the underground natural reservoir. More specifically, in Western Canada, crude oil producers use high pressure steam injection technology at a typical pressure range of about 1,500 to 3,000 psi (105.5-210.9 kg / cm ³ ), and in some cases 150 psi (10.55 kg / cm ³ ). The thermal energy of steam generated by a unit known as a steam generator, up to 60-80% of the quality of the steam, is injected into vertical or horizontal well systems to reduce the viscosity of crude oil. Flowing crude oil is collected in adjacent producing wells and a combination of crude oil, an oil / water emulsion, condensed steam and produced hard water (known as formation water) is supplied to the surface. Using ground-based equipment, crude oil is separated from process fluids and recovered for commercial sale. Formation water, typically recovered in a water / oil ratio of 2 to 5, is typically discharged into a well to discharge commercial wastewater. Added water from a groundwater source, for which there is an authorized permit, is used to power the steam generator. As a rule, minimal purification of the added water is required to reduce the stiffness and quantity of silicon dioxide compounds in order to avoid scale formation on the surfaces of the steam generator heat exchanger and to prevent the risk of equipment breakdown. In some equipment systems, concentrated formation water from the steam generator drain is separated from the steam injected into the reservoir and discharged into suitable deep wells to discharge the wastewater. Such concentrated formation water is also called a steamed stream. This prevents excess and unnecessary amounts of hot water from being pumped into the tank during steam exposure. Typical currently used crude oil production methods are steam cycling (CCS or Hull n 'Puff) and steam gravity drainage (SAGD) methods.

Due to public requirements and regulations, heavy oil producers must regenerate and reuse water, and some enterprises require zero discharge of wastewater. This means that 100% of the water used is recoverable and reusable and no wastewater can be discharged outside the development site. The produced water recovered in the oil separation units and high pressure steam separators contains hardness components, dissolved and suspended silica and colloidal compounds (clay), as well as dissolved solids such as sodium chloride. If such salt water is recycled without treatment, steam generators are at risk due to clogging and scale.

Another problem that is encountered today when using the steam stimulation method for the extraction of crude oils is that to increase oil recovery with increasing operating temperatures of productive reservoirs from 230 to 400 ° F (110-204.4 ° C), the temperature of the extracted fluid media (oil and water) rises. To facilitate the usual practice of atmospheric separation of oil and water, significant quantities of water vapor are generated when the pressure of the fluid decreases. This water vapor is typically condensed by external means, such as an air cooler, to recover condensed water. The thermal energy of condensed steam is released into the atmosphere as waste.

Up to the present invention, the combination of waste heat energy recovery with a highly efficient distillation water purification method, in which there is no clogging of equipment, by recycling the water produced along with the crude oil and waste brine was technically and commercially limited.

Basically, distillation water treatment is a highly efficient way to evaporate a pure aqueous distillate and recover a concentrated liquid or solid substance containing a large amount of non-volatile components. Such a method can be an effective means of extracting purified water from contaminated sources. However, the method of distillative water treatment usually has several disadvantages, and all of them are associated with contamination of the equipment or the formation of scale in it due to the presence of minerals or other components in the fluid to be distilled. Common solid precipitating compounds include calcium, magnesium, and silicon. Pollution or, to a greater extent, the formation of a solid precipitate on heat-conducting surfaces has a harmful effect on the operation of heat-conducting components, disabling the operation of the conventional distillation method.

US Pat. No. 4,566,947 dated January 28, 1986, discloses a conventional distillation method, but does not indicate the main factors necessary to prevent contamination, or the use of a method for treating formation water, which is an accompanying component in the production of heavy oils. The most important place in this patent is column 7, starting from line 55, with respect to Figure 4, where the following is noted: “The method that uses the steam compressor 307 in this way is advantageous in the case where the feed liquid contributes to the deposition of solids during condensation of its volatile component or clogging with material like pitch, which can cause an accident or lead to time-consuming repair and maintenance of the compressor. Using the equipment circuit described above, only vapor from the evaporator passes through compressor 307, thereby preventing such malfunctions. The interior of conduit 350 and evaporator 352 can be kept clean by using suitable flushing means. The above method has advantages especially when the residual liquid is water, since it seems possible to add cheap, non-regenerative process water through line 353. When the water that collects at the bottom of the column 306 does not contain substances that contaminate the inside of the compressor 307, it can be supplied to the evaporator through line 353 to maintain a constant liquid level in the evaporator.

Figure 4 of this patent is reproduced below, as well as an additional figure (amended Figure 4), essentially corresponding to Figure 4, which includes a device submitted by the applicants for implementing this method.

As can be seen from the consideration of Figure 4 of this patent and the applicants' device, superimposed on the scheme of this patent, if to the US patent No. 4566947 add a forced circulation circuit of the evaporator and when determining the specific ratio of steam flows, the residual liquid water may contain pollutants and work without pollution or scaling on heated surfaces.

In FIG. 4 of said patent, pipelines 340 and 353 are not connected. There is no connection between the bottom portion 306 and conduit 353. Section 306 in the column is defined as the bottom portion of the column containing residual liquid with a predetermined concentration of ammonia. This patent notes the fact that the method has advantages, especially when the residual liquid is water. It is assumed that these figures do not offer and do not determine the nature of the circulation of residues from the bottom of the column. There is only a general reference to flows 34 and 35 in column 3, lines 19 to 23. It is indicated that the residual liquid in column 1 is sent to the evaporator through line 34, and the heated residual liquid through line 35. In addition, line 20 indicates that liquid residues from the bottom of the column are heated by generating heat from condensation of the compressed steam. After carefully studying the description of this invention, it turned out that it does not contain any mention of the ratio of vapor or vapor to liquid.

The said patent clearly states that if the water that collects at the bottom of the column does not contain any clogging substances, this water can be fed to the evaporator. The present invention is independent of the nature of the feed stream associated with the possibility of clogging the evaporator. Water contaminated with contaminants can be fed directly to the evaporator without fear of clogging or other damage to the heat exchanger. In fact, this is the exact opposite of what is indicated in the patent. When considering the loop circuit in FIG. 4 of the patent, all heated surfaces associated with liquids accumulating at the bottom of the column in the depicted installation never come into contact with anything other than water, essentially free of contaminants contaminating the equipment, and this water used as the main medium for the distillation of ammonia from a mixture of ammonia and water. The reference patent in column 3, line 19 indicates "... the residual liquid of column 1 is sent to the evaporator 8 through line 34, where it is heated by condensation of the compressed [in this way] steam from the compressor 7, while the heated residual liquid is circulated to the bottom of column 6 through a 35 "pipe.

If you combine the instructions from column 7 above with the instructions from column 3, the result will only be clogging the installation. US Pat. No. 4,566,947, by combining these indications, provides information that can only infest a unit. In contrast, the method of the present invention effectively provides a system in which an inlet stream that contains water is contaminated with impurities is taken and fed into the installation without any fear of clogging of the surfaces of the heat exchanger.

This is possible in light of the recognition of bubble boiling and the importance of this physical phenomenon in maintaining a wet surface in a circuit including a heat exchanger. As is known, the bubbling boiling regime for accumulations of water at atmospheric pressure is a very specific region where individual bubbles form. This was defined in the reference document Principles of Heat Transfer, Third Edition, Frank Kreith; and Heat Transfer, Seventh Edition, J.P. Holman.

The Principles of Heat Transfer link on page 498 discusses relatively stable film and bubble boiling. In this passage, reference is made to FIGS. 10-2 as illustrating bubble boiling. Obviously, individual bubbles form on the wire shown in the figure. This phenomenon is also illustrated in FIGS. 9-5 on page 520 of the second reference document. Heat Transfer. In this reference, the author does acknowledge on page 519 that there is a significant divergence of opinion regarding the mechanism of bubble boiling. In this particular case, the importance of maintaining bubble boiling is recognized. This concept is important for maintaining a moist surface on the heat exchanger, and it is this that helps ensure that the incoming stream containing any contaminants does not come into contact with the surface of the heat exchanger and there is no risk of clogging. When the proportion of steam is more than 50%, the heat exchanger is really clogged.

The technology below provides the purification of an incoming stream containing clogging impurities. Clogging impurities in the incoming stream can come into direct contact with the surface of the heat exchanger without any clogging. This last feature is not possible in the invention according to the specified US patent by his own admission. This excerpt from the description is presented above. The recognition of the above principles is what allows this method to achieve the desired results. The method of this patent is simply not applicable to this invention.

Another common problem with typical distillation water treatment methods is the need to consume large amounts of energy. Without an energy source of waste heat and means of efficiently regenerating this consumed energy, the amount of energy needed is equivalent to the latent heat of evaporation of water at a given pressure or temperature. Water distillation under such conditions cannot be the commercial method used to improve water quality. The extraction target for crude oils is high-energy fluid flows suitable as sources for regenerating waste heat energy.

To solve the problems associated with traditional distillation methods, the following variables must be considered. The following three equations represent the main dependencies of heat transfer in a water distillation system:

O _(total) = U · A · LMTD (1)

Q _{(detected heat)} = m · CP · (T1-T2) (2)

Q _{(latent heat)} = mL (3)

where Q = amount of heat transferred (VTG hour ^-1 (BTU = British thermal unit))

U = total heat transfer coefficient or system heat transfer capacity (BTU hour ^-1 ft ^-2 F ^-1 )

A = heat transfer surface area (ft ² )

LMTD = logarithmic value of the temperature differential or system heat transfer (F)

m = mass flow rate of the liquid in a liquid or gaseous state (lb hour ^-1 )

Cf = specific heat of the liquid (BTU hour ^-1 F ^-1 )

T1, T2 = temperature of the fluid entering or leaving the system (F)

L = latent heat of vaporization or condensation (BTU lb ^-1 )

In order to obtain an effective distillation system, the amount of exchanged and regenerated heat Q, expressed by the above equations, should be maximized, but at the same time, observing practical restrictions for the remaining variables and preventing the formation of scale and clogging. For a specific fluid and fluid dynamics within a specific heat exchange installation, the variables U, Cp and L are relatively unchanged. Therefore, to solve the problems associated with the distillation treatment of water containing contaminants, special attention should be paid to the variables A, Q / A, LMTD, m and T1 and T2.

In order to completely solve the problems associated with the distillation of pollutant-containing water from crude oil by thermal methods and to prevent scale formation, in addition to the basic equations given above, other factors must be taken into account:

transformation of efficient energy sources of waste heat;

the rate at which heat is transferred through the distillation system, known as heat consumption or QA ^-1 (BTU hour ^-1 foot ^-2 );

level of contaminants in the concentrate;

the final boiling point of the concentrate relative to the saturation temperature of the evaporated steam;

degree of supersaturation and sedimentation level of the concentrate;

evaporation rate of evaporated steam.

Prior to the present invention, efficient recovery of waste heat energy from crude oil production facilities and maximizing the amount of heat transferred and regenerated by using a distillation water treatment method that does not tend to clog or scale, could not be realized for a long time.

A method has been developed that is both energy-efficient and eliminates the problems of scale formation that had previously been encountered in the distillation treatment of water containing, among others, contaminants such as organic compounds, inorganic compounds, metals.

The invention further develops the concept defined in the initial application. Previous concepts linked two different concepts, including distillation or multi-purpose distillation water treatment using steam recompression and waste heat recovery in combination with a unique heat recovery scheme. It was found that by further combining the recovery of low-grade heat from a thermal oil recovery unit with a unique configuration of the heat recovery and transfer system with forced convection, very favorable results can be obtained, namely, obtaining maximum heat transfer, eliminating or minimizing the need for energy compressing and maintaining the desired forced convection pattern so as to prevent conductivity leading to scale formation in the heat transfer nicknames that usually occurs in the practical application of conventional distillation methods.

It was found that the use of waste heat energy from a crude oil recovery unit can be regenerated in a heat transfer scheme, and this low-grade energy source, which in most cases was dumped as excess energy or non-regenerated energy, is used to reduce or reduce to zero the amount of compression required to process waste water and a significant reduction in the commercial profitability of this method.

According to the presented methodology, the energy source is a high-pressure discharged liquid from a high-pressure steam separator, which is evaporated to reduce pressure to obtain low-grade steam and hot formation water at an overpressure of 10-15 psi (0.7-1 kg / cm ² ) Low pressure steam is used in a heated separator as a heat source for evaporating purified water, which then condenses to produce high-quality water for supply to a steam boiler. Hot concentrated steamed stream is used to preheat the incoming stream of produced water before it enters the heated separator.

In addition, a significant source of waste energy is obtained from the depressurization of the working fluids exiting the crude oil tank. The pressure of the working fluid, usually when they exit the tank 50-300 psi (3.5-21.09 kg / cm ² ), dump to about atmospheric in the degassing separator. The working oil / water fluids are transferred to a conventional atmospheric oil / water separation device known to those skilled in the art. Waste energy can be extracted in two ways. If the carrier gas is not used in the crude oil production method and after the wellhead in the working fluids there is only a minimal amount of associated gas, the exhaust steam is separated from the degassing tank and fed to a highly efficient distillation unit for recovering the energy of the waste heat. If a carrier gas is used in the wellbore to produce crude oil and / or a relatively large amount of associated gas is present in the working fluids, then the waste heat energy can be regenerated using suitable heat transfer means and transferred through the hot fluid to a highly efficient distillation unit for recovering the spent energy heat. In this example, the cooled working fluids are degassed in a degassing tank without any noticeable vapor loss. The current state of the art for thermal stimulation methods is to enhance the regime in the oil reservoir to increase crude oil production, which gives higher temperatures of the working fluids in the wellbore. These temperatures reach levels typically above 230-400 ° F (110-204.4 ° C) and even 500 ° F (260 ° C). Therefore, a significant amount of regenerated waste heat energy is available as a source for a highly efficient distillation water treatment plant.

The technical result of the present invention is the creation of improved effective extraction of produced water for distillation treatment of water containing organic, inorganic compounds, metals and other pollutants, which results in a purified aqueous fraction that does not contain pollutants, and in addition does not lead to the formation of scale in distillation unit.

This technical result is achieved in that the method of producing energy for water treatment, used in the extraction of crude oil from an oil reservoir containing crude oil and water, according to the invention, comprises the following steps:

a) ensuring the incoming flow of water;

b) processing the incoming water stream to form a vapor fraction and a liquid fraction;

c) the use of a steam separator to separate the vapor fraction and the liquid fraction;

d) separation of the vapor fraction and the liquid fraction;

e) the use of an oil and water separator and a water distillation unit;

f) injection into the reservoir of the vapor fraction;

g) the collection of crude oil and produced water from the oil reservoir in the oil and water separator;

h) separation of crude oil and produced water from the separator;

i) supply of thermal energy contained in the liquid fraction to the water distillation unit;

j) treatment of produced water in a water distillation unit.

The incoming water stream is conditioned before being contacted with a steam generator. The incoming water stream is conditioned to remove mineral impurities.

Crude oil from stage h) has a density of 7 to 20 ° on the scale of the American Petroleum Institute.

The method may further include the step of using a heat exchanger to obtain at least a portion of the thermal energy in the liquid fraction.

The method may further include the step of heating the incoming water stream with at least a portion of the energy received from the heat exchanger.

Crude oil production may include a gravity drainage method of steam production.

Crude oil production may include cyclic steam stimulation.

Crude oil production may include steam and gas propulsion.

The above technical result is also achieved by the fact that it provides a method of obtaining energy from equipment for the extraction of crude oil contained in the oil reservoir, while the energy of water treatment is obtained by extracting crude oil, while the specified method according to the invention contains the following stages:

a) using a steam source containing a vapor fraction and a liquid fraction;

b) the use of an oil-water separator and a water distillation plant;

C) injection into the oil reservoir, at least part of the vapor fraction and the liquid fraction to extract crude oil;

d) the collection of crude oil and water from the oil reservoir in the oil and water separator;

d) separation of crude oil and produced water from the separator;

f) supplying thermal energy contained in the liquid fraction to the water distillation unit;

g) treatment of produced water in a water distillation unit.

A method of producing energy in the processing of crude oil for purification of water obtained from the extraction of crude oil according to the invention comprises the following steps:

a) providing a purge flow of high pressure;

b) instantaneous evaporation of the purge stream of high pressure with the formation of a stream of spent energy low pressure and concentrated stripped stream;

c) evaporation of produced water using a stream of waste energy of low pressure;

g) pre-heating the incoming stream of produced water using concentrated steamed stream;

e) providing a fluid circulation circuit including a heated separator and an evaporative heat exchanger communicating through a fluid stream;

e) passing a preheated incoming stream of formation water into a heated separator;

g) passing the spent energy to the evaporator to obtain thermal energy;

h) evaporation of the flow of produced water using the spent energy in the evaporator-heat exchanger to form a vapor fraction and a concentrated liquid fraction containing contaminants;

i) the circulation of at least part of the concentrated liquid fraction through the evaporator-heat exchanger and a heated separator to maintain the mass ratio of the concentrate to the vapor fraction from 300 to 2, resulting in about 1% wt. up to less than 50% wt. the exit of the vapor fraction from the evaporator-heat exchanger in order to prevent clogging and scale formation in the evaporator;

j) condensation of the vapor fraction by external condensing means;

k) collecting the condensed vapor fraction and the waste energy stream substantially free of contaminants.

Optionally, a compressor can be used to condense part of the vapor fraction to distilled water when the amount of waste energy is sufficient for the heated separator.

The method may include the step of passing the vapor fraction into the crystallizer of solids to extract energy contained in the vapor fraction to form solid contaminants in the crystallizer from non-volatile compounds present in the concentrated liquid fraction containing contaminants.

The method may include the step of passing a vapor fraction into an external condenser to condense the vapor into a liquid.

The amount of waste water treated containing contaminants may be equivalent to the amount of waste energy obtained by this method.

The incoming stream may be subjected to a pre-treatment scheme before pre-heating. The pretreatment scheme can be selected from the group including the following: filtration, ion exchange, gravity separation, chemical treatment and steaming.

The method may further include the step of subjecting the condensed distillate to a post-treatment scheme.

The post-treatment scheme can be selected from the group including the following: filtration, ion exchange, in-depth oxidation, adsorption and aeration.

The above mass contains about 10% wt. steam concentration.

Steam can be condensed in a plate-plate heat exchanger.

A further aspect of the present invention is to provide a method for producing energy in the processing of crude oil for processing water obtained from the extraction of crude oil according to the invention, comprising the following steps:

a) providing a purge flow of high pressure;

b) instantaneous evaporation of the purge stream of high pressure with the formation of a stream of spent energy low pressure and concentrated stripped stream;

c) evaporation of at least a portion of the formation water using a low pressure waste energy stream;

g) pre-heating produced water using a concentrated steamed stream;

e) providing a fluid flow pattern including interconnected heated separator and evaporative heat exchanger;

e) providing a vapor flow pattern including a heated separator, compressor means and an evaporator-heat exchanger communicating with each other;

g) passing the pre-heated produced water into the heated separator;

h) evaporation of preheated formation water using the spent energy of low pressure and compressed evaporated steam in an evaporative heat exchanger to form a vapor fraction and a concentrated liquid fraction;

i) mining of the vapor fraction formed by the spent energy of low pressure using external means of condensation;

j) recovering any remaining vapor fraction using a compressor;

k) the circulation of at least part of the concentrated liquid fraction through the evaporator-heat exchanger and the heated separator to maintain the ratio of the mass of the concentrate to the vapor fraction from 300 to 2 to obtain the output of the vapor fraction from the evaporator-heat exchanger in an amount of about 1% wt. up to less than 50% wt. in order to prevent clogging and scale formation in the evaporator-heat exchanger;

m) collecting fractions of condensed steam and a stream of waste energy that does not contain contaminants.

And another additional aspect of the present invention is the creation of a method of producing energy in the processing of crude oil for processing water obtained from the extraction of crude oil, according to the invention, containing the following stages:

a) providing a purge flow of high pressure;

b) instantaneous evaporation of the purge stream of high pressure with the formation of a stream of spent energy low pressure and concentrated stripped stream;

c) evaporation of produced water using a stream of waste energy of low pressure;

g) pre-heating produced water using a concentrated steamed stream;

e) providing a fluid circulation circuit including a heated separator and an evaporative heat exchanger communicating with the aid of a fluid stream;

e) passing the incoming stream of produced water into the heated separator;

g) passing the flow of waste energy of low pressure into the evaporator;

h) evaporation of produced water using the spent energy of low pressure in the evaporator-heat exchanger for the formation of the first vapor fraction and containing contaminants in the concentrated liquid fraction;

i) circulation of at least a portion of the concentrated liquid fraction containing impurities through the evaporator-heat exchanger and a heated separator to maintain the mass ratio of the concentrate to the vapor fraction from 300 to about 2 to obtain a vapor fraction exit from the evaporator-heat exchanger from about 1% wt. up to less than 50% wt. in order to prevent clogging and scale formation in the evaporator;

j) the use of crystallization means and an evaporator-heat exchanger communicating with a vapor fraction;

k) removing a portion of the concentrated liquid fraction containing contaminants for feeding into the crystallization means;

m) passing the vapor fraction into the evaporator to provide thermal energy for the deposition of solids from the concentrated liquid fraction containing contaminants;

m) the formation of a second fraction of steam from the crystallization means and steam from a substantially solid fraction;

o) condensation of the second vapor fraction by means of a condenser;

m) collecting the condensed first vapor fraction and the condensed second vapor fraction and the condensed waste energy stream.

Additional benefits of this technique are zero cost. This is due to the fact that it becomes possible to use a sufficient amount of low-grade waste energy, and therefore, when treating formation water, it is not necessary to use a compressor. In addition, this method scheme facilitates the extraction of 100% water, resulting in a zero amount of wastewater containing contaminants in the solution, since the contaminants are converted into solid waste.

And another aspect of the present invention is a method of producing energy for water treatment used in the extraction of crude oil from an oil reservoir containing crude oil and water, according to the invention, comprising the following steps:

a) ensuring the incoming flow of water;

b) processing the incoming water stream to form a water vapor fraction and a liquid fraction;

c) providing a steam separator for separating the water vapor fraction and the liquid fraction;

d) separation of the water vapor fraction and the liquid fraction;

e) the use of an oil and water separator and a water distillation unit;

f) injection of the water vapor fraction into the oil reservoir;

g) depressurization in the flow of crude oil, produced water and water vapor leaving the oil reservoir;

h) transfer of energy contained in water vapor to a water distillation unit;

i) separation of crude oil and produced water.

The method may further include the step of providing heat energy contained in the liquid fraction to the water distillation unit.

And another aspect of the invention is a method

generating energy for water treatment used in the extraction of crude oil from an oil reservoir containing crude oil and water, according to the invention, comprising the following steps:

a) ensuring the incoming flow of water;

b) processing the incoming water stream to form a water vapor fraction and a liquid fraction;

c) using a steam separator to separate the water vapor fraction and the liquid fraction;

d) separation of the water vapor fraction and the liquid fraction;

e) the use of an oil and water separator and a water distillation unit;

f) injection of the water vapor fraction into the oil reservoir;

g) receipt of thermal energy of crude oil and produced water leaving the oil-bearing formation by means of heat exchange;

h) separation of crude oil and produced water;

i) supply to the installation of distillation of thermal energy from the heat exchanger;

j) supplying thermal energy contained in the liquid fraction to the water distillation unit;

k) treatment of produced water in a water distillation unit.

It has been found that by precisely controlling the amount of circulating mass so that it exceeds the amount of the vapor fraction leaving the evaporator from less than 300 to about two times, some of the desired advantages can be realized:

1. The concentrate circulating through the evaporating side of the evaporator will contain a precisely controlled amount of steam from about 1% to 50% by weight of the circulating concentrate.

2. With precise control of this amount of steam, the temperature rise of the circulating concentrate remains very low (about 1 ° F) and the heat transfer surfaces of the evaporator remain wet at a temperature close to the temperature of the circulating concentrated liquid. This reduces the risk of clogging of these surfaces.

3. With such a controlled low amount of steam, the concentrated liquid in the heat exchanger is subjected to an even lower localized concentration coefficient of less than 1.1, while localized deposition of scale-forming compounds on the surfaces of the heat exchanger is avoided.

4. As the mass of steam forms in the direction of exit from the evaporator, the vapor velocities in the passages of the heat exchanger increase significantly, thus contributing to good mixing and, therefore, reducing the risk of clogging.

5. When controlling the amount of steam in the evaporated fluid, it is possible to carry out significant heat transfer through latent heat means, without scaling and temperature crossing inside the heat exchanger.

6. Since a very insignificant increase in the temperature of the evaporating side of the evaporator is maintained, the average logarithmic value of the temperature differential or heat transfer of the evaporator is maintained, and thus there is a very small need for incoming energy.

7. By controlling the heat flux, the temperature of wet surfaces for condensation and evaporation is maintained close to the temperature of the state of saturated steam during evaporation and condensation modes. The type of boiling used can vary from initially forced convection to stable bubble evaporation of wet wetted surfaces.

8. By providing evaporator means for adsorbing low-grade waste heat energy from heavy oil recovery facilities, less compression energy is required, provided that sufficient high-pressure purging is provided.

In one embodiment of the invention, in its wide volume, distilled water is evaporated and passed through a strainer to remove any retained droplets, where it is condensed by external means. The waste energy stream enters the evaporator, where it condenses to distillate. Heat energy is transferred to the circulating concentrate from a heated separator, where by controlling the ratio of the mass of the circulating concentrate to the steam stream so that it is in the range from less than 300 to about 2, less than 50% of the steam is formed, or more precisely less than 10% of the steam in the circulating concentrate stream . This steam formed in the circulating concentrate absorbs the transferred heat through the latent heat of evaporation, at the same time preventing the temperature of the circulating concentrate from increasing by more than 1 ° F. Pure distilled water collected from an external condenser and evaporator-heat exchanger at temperature and pressure condensation is returned in the form of high-quality water supplied to the steam generator. At the same time, part of the concentrate stream is removed from the heated separator to control the desired concentration of non-volatile contaminants. This concentrated stream, from which steam was released, at a pressure and temperature of the heated separator is passed through a heating device to transfer the remaining heat energy to the incoming stream of produced water. Additional pretreatment and posttreatment techniques can be used as continuous or batch processes to remove or treat contaminants before, after, or during the distillation process. You can use the methods of pH control and other chemical additives to ionize the volatile components or change the dissolution conditions in the concentrate in order to further improve the distillation method of the present invention. A very significant amount of distilled water can be regenerated, typically more than 90% of the incoming water stream. When crystallization agents are additionally used, 100% regeneration is achieved. With regard to the breadth of this method, it is easily applicable to any operation of crude oil production using steam for thermal stimulation, for example, in the traditional steam flooding method, cyclic steam stimulation method (CSS or Huff n 'Puff), gravity drainage method using steam ( SAGD) and vapor and gas ejection method (SAGP). This list is by no means exhaustive, but is provided as an example only.

The invention will now be described in more detail with reference to the accompanying drawings, in which:

figure 1 depicts a diagram of the method as a whole in accordance with one embodiment of the present invention;

figure 2 - diagram of the method as a whole in accordance with another embodiment of the present invention;

figure 3 - diagram of the installation of water treatment for the method according to the invention;

figure 4 is an alternative embodiment of the method of figure 2;

5 is an alternative embodiment of the installation of figure 3;

6 is a schematic illustration of typical pressure and temperature conditions around evaporation components;

7 is a curve of the process of condensation or evaporation for the evaporator-heat exchanger system;

Fig. 8 is a flow diagram for a plate / plate type evaporator-heat exchanger;

Fig.9 is a diagram illustrating the level of evaporation in the evaporator taking place in a circulating fluid, depending on the ratio of the mass of the circulating fluid to the mass of water vapor;

figure 10 is a diagram illustrating the resulting effect of localized concentration in the evaporator when changing the amount of steam;

11 is a diagram representing test data of a pilot distillation plant;

12 is a diagram of a method as a whole in accordance with the following one embodiment of the present invention;

13 is a diagram of a method as a whole in accordance with another embodiment of the present invention.

1 will present one embodiment of the present invention. The water supplied to the steam generator 125 is collected in a supply tank 110 for water. The water is taken from a suitable source of groundwater 105, or it may be water 100, which is recycled or added from traditional processing methods, such as softening calcareous and alkaline impurities, softening by ion exchange or distillation. First, hardness components such as calcium, magnesium, or silicon dioxide must be removed from the feed water to prevent the formation of solid deposits on high pressure steam generators 125. An additional consideration is that the dissolved solids should be less than 8000 ppm (by weight) to produce high pressure steam of the desired 80% quality. The total amount of dissolved solids (RTB) mainly consists of sodium chloride. Volumetric amounts of water can vary from a low amount of 10,000 barrels per day (BVD) (159 · 10 ⁴ liters per day) for pilot plants for the extraction of heavy oils by thermal methods to more than 100,000 BVD (159 · 10 ⁵ liters per day) for commercial thermal oil extraction plants.

The conditioned water from the reservoir 110 is pumped through a series of pressure pumps 115 into a high pressure steam generator 125. A typical 125 steam generator generates 60-80% quality steam at an overpressure of 1000 psi to 3000 psi (70-210 kg / cm ² ) or more, depending on the nature of the oil reservoir. This type of oilfield steam generator, known to those skilled in the art, is limited to less than 100% steam quality due to the specific design and the limitations associated with scale formation in the pipeline. Other evaporators, traditional steam boilers and evaporators that simultaneously recover heat if high-quality water, such as distilled water, is commercially available, can be used to generate 100% quality saturated steam or superheated steam.

In some reservoirs of crude oil, for example, reservoirs of crude oil, in which a gravity drainage method using steam cannot be used, steam of less than 100% quality cannot be pumped into the reservoir without performing an oil recovery operation. For these operations, a high pressure steam separator 130 is used to separate saturated steam 135 from the high pressure liquid phase 140, which is also called superheated brine. Some tools use part of the energy available at position 140 by heat exchange at position 120 with water supplied to the steam generator before releasing the pressure. The amount of recoverable thermal energy depends on the vapor pressure level at position 135, but basically it is limited to a small amount. Therefore, in most gravity drainage methods that are used for the extraction of crude oil, there is a significant amount of waste heat energy in stream 140, which is of limited use and such heat is typically removed to a cooling tower or cooling apparatus such as waste heat. Such a waste energy stream can be supplied to a high-performance distillation unit 180 for treating formation water 175, which significantly affects the reduction in the commercial cost of treating the water and the improvement of production costs in the production of crude oil. The most important, however, are the environmental benefits, which include eliminating the added water and the contaminant-containing water and a significant portion of the spent energy in this method, which reduces the consumed flue gas and the overall air emission.

High pressure steam 135 is injected into oil reservoir 145 through well bore 150. Depending on the method used for producing crude oil, the configuration of the well may be different. Figure 1 shows a typical location for a gravity drainage method where steam is injected into a horizontal wellbore, and produced fluid containing crude oil is recovered in an adjacent horizontal wellbore 155. The produced fluids are received at the surface and transferred via production pipelines 160 to the oil recovery unit 165. Crude oil having a density of less than 20 ° ANI and greater than 7 ° ANI is recovered and sold commercially for refining.

Produced water 175, obtained in a typical ratio of water to oil from 2 to 5, is fed to a water treatment unit 180. Formation water contains sodium chloride, silicon dioxide, dissolved organic hydrocarbons, calcium and magnesium, which primarily come from a natural oil reservoir and a source of initially added water.

Wastewater or solids containing concentrated brine may be extracted from water treatment unit 180 as stream 185.

This stream typically does not have commercial value and requires discharge on-site or off-site, depending on the placement of crude oil production equipment.

Typically, a 180 high-performance distillation water treatment plant 180 regenerates more than 80% to 100% of produced water in the form of pure distilled water in stream 100.

Figure 2 presents another embodiment of the present invention. This option represents crude oil production equipment, where the temperature requirements for the produced fluids after the bore 155 of the producing well and the wellhead 160 are such that the temperature should be higher than usual 230 ° F (110 ° C) and reach 400 ° F- 500 ° F (204-260 ° C) in order to increase oil production. Hot liquids recovered from the well pass through a degassing separator 161 while lowering the pressure at 162 to be fed to the oil and water separation unit. Water vapor is generated from the degassing separator 161 at a typical overpressure of 40-60 psi (2.8-4.3 kg / cm ² ) (typically less than 100 psi (7 kg / cm ² ). This low-grade steam 163 is fed to a high-performance distillation water treatment unit 180 for use in evaporating distilled water from produced water. fluid 160.

If, in general, they do not encounter a sufficiently large amount of associated gas in the crude oil, and / or the carrier gas is artificially injected into the well bore 155 of the producing well, then a backup method of generating energy is necessary. The extracted hot fluids are passed through any suitable heat transfer means to drastically lower the temperature before entering degassing separator 161. The waste heat energy is recovered from position 164 using a suitable heat transfer medium and transferred via stream 166 to a high-performance distillation water treatment plant 180 for treating water to produce distilled water.

As shown in FIG. 2, both heat generation methods using streams 140 and 166 can be used separately or in combination depending on the operating conditions of the natural oil reservoir 145 and the benefits derived from using each of these methods.

Next, with reference to FIG. 3, an embodiment of a highly efficient distillation water treatment apparatus 180 is provided.

The incoming formation water stream 175 is fed to a pretreatment step 12 to remove insoluble substances, volatiles, and / or other pH adjusting or conditioning steps to pretreat the incoming stream 175. Volatiles are discharged from the feed stream at position 14, while less volatile the components are discharged from the incoming stream at position 16. The pre-processed incoming stream leaving position 12 is then passed to the preheating device 18 for increasing the temperature of the incoming stream in order to increase heat recovery before being introduced into the heated separator 20. The incoming stream can be divided into several streams and passed through other secondary devices for preheating and increasing heat recovery to maximize the use of the regenerative potential of the installation. Such a scheme will be understood by specialists. Several preheating devices may be configured as a single multi-service preheater or individual devices 18 and 26. The individual incoming streams are again combined and heated to conditions close to the heated separator before the stream enters the heated separator 20. If desired, the incoming stream can be also introduce into the forced circulation stream to create a dilution effect in the evaporator. The heated separator may include a multiple separation device, such as a cyclone separator. The lower section 22 produces a cyclone action for suspending the solid material in the concentrate and supplying what is called a steamed stream or concentrate, as shown by line 24. The consumption of the steamed stream 24, continuous or batch, controls the concentration of the components in the heated separator 20, thereby controlling the degree of saturation concentrate, the degree of supersaturation, the corresponding precipitation of solids and the boiling point in the heated separator 20. The steamed stream 24 at a temperature and concentration, is set s in the heated separator 20, is passed through a secondary heating unit 26 for heat recovery to the feed stream 28. The stripped stream is reduced to a temperature in the range of about 3 ° F (-16 ° C) for approximation to the incoming flow 12 and discharged as stream 185.

The upper section of the heated separator 20, containing mainly saturated water vapor, is designed to separate the vapor and liquid and may contain such distinguishing features as a mesh filter layer or a turbine unit (not shown) for coalescing liquid droplets from the steam stream. The steam leaving the heated separator 20 and generally indicated by line 30 constitutes an environmentally friendly distillate and, depending on the components present in the inlet stream, may consist of potable water or water suitable for use in an evaporator. Part of the steam is transferred to the compressor 32 to increase the temperature and pressure of water vapor to a temperature higher than the temperature of the heated separator 20. At the outlet of the heated separator, water vapor can be at any pressure, including vacuum. This steam is initially saturated under conditions of a heated separator 20, however, it can become supersaturated if the concentrate contains components in a concentration sufficient to increase the boiling point of the steam. Such a concept is known as an increase in boiling point, and it must be understood so that appropriate compression compensation is necessary. The additional energy provided to the water vapor helps to establish the required average logarithmic value of the temperature differential or heat exposure necessary for the heat transfer in the evaporator-heat exchanger 34. Any remaining portion 46 of the steam is transferred to any suitable external condensation device 58 to recover the steam in the form of distilled water in position 48.

The compressor or blower 32 may be any device known to those skilled in the art that can induce a gas pressure of about 3 to 15 psi (0.211-1.055 kg / cm ² ) into the steam stream and the desired amount of steam flows. The gas pressure that must be obtained from the compressor 32 is specifically determined for each installation, taking into account the evaporation conditions in the heated separator 20 and the required average logarithmic temperature differential for the evaporator 34. The steam leaving the compressor 32 is mainly superheated water vapor. The degree of overheating depends on the outlet pressure and the efficiency of the compressor device 32. The spent energy in the form of low-pressure saturated steam, typically at an overpressure of less than 100 psi (7.03 kg / cm ² ), more specifically less than 50 psi . inch (3,515 kg / cm ² ), you can add to the compressed steam before it enters the evaporator-heat exchanger 34. The combined stream reduces the degree of overheating created by the compressor.

The evaporator-heat exchanger 34 provides condensation of the combined vapor stream obtained from the compressor 32 and the source 51 of the waste energy to distill the sludge from the evaporator 34 to the condensate receiver 36. This is the stage of capturing the superheat energy and latent heat of the combined steam stream and transferring it by means of heat transfer to the circulating concentrate stream 38. The distillate accumulated in the receiver 36 mainly represents a saturated liquid at a certain temperature and pressure. The additional heat contained in the distillate is regenerated by passing the hot distillate using pump 40 back through the preheater 18, where the effluent is cooled to about 3 ° F (-16 ° C) in the inlet from position 12. Distilled water from the receiver 36 and 48 can be combined to produce significant heat before entering the heating device 18, and it is discharged as stream 100.

It has been found that by using a pump 42 for circulating a concentrate that circulates a predetermined amount of concentrate from a heated separator 20 through an evaporative heat exchanger 34, significant advantages can be obtained without an excess concentration of the concentrate and without the risk of clogging or scale formation on the surfaces of the heat exchanger. The ratio of the mass of circulating concentrate to steam is specifically selected in the range of less than 300 to about 2, in order to obtain the exact amount of generated steam from about 1% to less than 50% in the stream 38 leaving the evaporator-heat exchanger 34. This mass of the stream can be changed and set it desired parameters by using a control device 44. More specifically, the desired amount of steam in the exit circulating stream 38, taking into account the most contaminated incoming streams, is less than 10% of the vapor fraction. The steam generated in stream 38 is the mass equivalent quantity recovered as distillate at position 100. The steam generated in the evaporative heat exchanger 34, although its mass fraction is very small (about 1 to 10% of the circulating mass), absorbs the greatest amount of heat transferred from the condensing side of the evaporator 34. The choice of the amount of steam and the rate of circulation of the concentrate is an important factor in reducing clogging and scale formation, as well as preventing excessive concentration of the fluid in the heat exchanger. To a greater extent, this parameter is most important for establishing a very low temperature rise on the circulating concentrate fluid to maintain an effective average logarithmic value of the temperature differential without crossing the temperatures in the evaporator-heat exchanger 34. Any temperature rise very quickly eliminates the indicated value of the temperature differential, and heat transfer stops. For example, if the pressure of the circulating concentrate was increased in the evaporator so that the fluid could not form a certain amount of steam, the temperature would rise due to the absorption of the heat content until there was an average logarithmic value of the temperature differential or thermal effect and, thus, heat transfer will decrease. It is calculated that the back pressure of the circulating concentrate system, consisting of static pressure losses and pressure losses due to friction, is minimal. In fact, the back pressure is, first of all, equal to the loss of static pressure in the vertical heat exchanger, while the dynamic pressure drop of the heat exchanger is minimized. The flow of the circulating concentrate is then taken to obtain from about 1% to 10% of the vapor fraction in the outlet pipe 338. The resulting temperature rise is extremely low, and the indicated average temperature differential remains at the calculated level.

Figure 3 illustrates an embodiment of the invention where saturated waste water vapor is combined with compressed water vapor to absorb waste heat energy in a single evaporator 34. The combined steam is condensed to form a condensed distillate. If the existing pressure of the exhaust steam is incompatible or cannot be made compatible, in this case, separate circulating loops of the concentrate and heat exchanger evaporators are provided, specially designed to correspond to each heat source. In addition, if the waste heat is only available through non-condensing heat transfer fluid means, then the exchange of waste heat is calculated so as to extract heat from the conveying fluid without a condensed distillate. A key design feature of an evaporator should always be its ability to maintain such a preferred ratio of liquid mass to vapor mass to create a vapor fraction of 1% to 10% in the vaporized fluid.

Figure 4 shows another diagram of the method, which makes it possible to control the stripped stream 24 from the heated separator 20 until the general concentration effect or the concentration coefficient of the system leads to the formation of a supersaturated concentrate in relation to one or more components, which causes their precipitation. While solids are formed and accumulate in the heated separator 20, the stripped stream 24 is passed through a device 50 separation of solids and liquids to remove solids or sludge. Alternatively, the solid-liquid separation device 50 may be placed between the pump of the evaporator 42 and the heat exchanger 34, in the flow path or in the general layout of the flow treatment equipment. The recovered liquid is then recycled back to the heated separator 20, as shown at 52, and a portion representing the amount of stripped stream is then passed through a heater 26 to produce heat and cooled to about 3 ° F (-16 ° C) of stream 175. Separation device 50 solids and liquids may be in any form known to those skilled in the art, such as a filter, a hydrocyclone, a centrifugal separator, a gravity separator, a centrifuge, a decanter. This method is particularly preferred when the main objective is to recover the compound as a solid, or when such a compound has significant commercial value.

Figure 5 presents another embodiment of the method in which the steam stream may contain part of a particular pollutant from the incoming stream. The heated separator 20 is equipped with a fractionation column 54 located in front of the compressor 32 and the pipe 46 for excess water vapor. Column 54 is used for fractionation and leaching of contaminants using several stages in combination with a backflow 56 of pure cold water. The return flow can be removed from either the inlet or the outflow of the preheater 18, or a combination thereof depending on the desired return temperature. This process variant is particularly attractive when the incoming stream contains, for example, volatile substances such as hydrocarbons, glycols, ammonia, amines, etc.

6 illustrates typical pressure and temperature ratios of various streams around the evaporator portion of the method. Various references have been made for this discussion, starting from FIG. 2 to FIG. 4. Although specific process parameters are presented using an example, they can be modified to suit any specific distillation application. The figure schematically shows the conditions depending on the fluid, where the boiling point does not increase and the heated separator 20 operates at a pressure slightly above atmospheric, 16 psi (1.125 kg / cm ² ) and 212.5 ° F (100.28 ° C). The temperature rise of the circulating concentrate is 1 ° F for a vaporizer pressure drop of 2.5 psi (0.176 kg / cm ² ). The vapor fraction of the circulating stream is about 10%. The conditions around the evaporator-heat exchanger 34 can be represented in the form of a curve of evaporation or condensation, as shown in Fig.7. On the condensing side of the heat exchanger, superheated water vapor from the compressor at point C1 at a temperature of 289 ° F (142.78 ° C) and a pressure of 21.0 psi (abs) (1,477 kg / cm ² ) is connected to a saturated stream of the source of waste heat at point C2 and condenses when the vapor pressure is elastic at point C ', about 232 ° F (111.11 ° C) and 21.0 psi (abs) (1.477 kg / cm ² ). This zone is usually called the zone of lowering the temperature of superheated steam, and it consists of 2% of the surface area of the heat exchanger, the rest of the zone represents the area that releases the latent heat of condensation. The area of lowering the temperature of superheated steam decreases with increasing ratio of saturated waste heat to compressed steam. A slight drop in pressure and temperature in the heat exchanger 34 occurs due to the pressure drop characteristic of the heat exchanger. The output conditions are as follows: about 231.8 ° F (111 ° C) and 20.9 psi (1.47 kg / cm ² ). The surface temperature on the condensing side will be lower than the saturation temperature of the incoming steam, thus forming a condensate film on the surface of the heat exchanger. Heat transfer, therefore, occurs due to the wet state of the wall, which maintains the effective temperature of the film at a temperature of steam saturation. The distillate is drained from the heat exchanger to the condenser receiver 36 at point D, keeping the evaporator free of liquid and allowing the entire surface of the heat exchanger to condense.

On the evaporation side, the concentrate enters the heat exchanger counterflow from the bottom at point A at a temperature of about 212.5 ° F (100.28 ° C) and a pressure of 18.0 psi (abs) (1.266 kg / cm ² ) after circulation pump 42. The circulation speed is controlled so that the circulation speed of the concentrate mass is 10 times higher than the steam speed. The temperature of the fluid mass of the concentrate begins to rise to point A ', and then equalizes by about 213.2 ° F (100.7 ° C) when it reaches point B, where the hydrostatic head is overcome and the pressure drops to 15.5 psi ( abs) (1.08 kg / cm ² ). As the concentrate rises in the heat exchanger 34, steam generation begins under the action of forced convection with absorption of the latent heat transmitted. By increasing the mass of the fluid on the evaporating side until the ratio of the circulating mass to the mass of steam reaches the desired limits, the boiling effect is controlled within the forced convection and stable bubble boiling regions. Due to the large mass of the fluid stream, the heat transfer surface remains wetted at a temperature equal to the saturation temperature of the newly formed steam. With additional flow rate (QA ^-1 ) for the heat exchanger below 6000 BTU hour ^-1 foot ^-2 (162750 kcal / m ² · hour), the temperature rise on the evaporating side can be maintained at less than 1 ° F while maintaining a wet layer on the surface, thereby eliminating the risk of scale formation. If the flow rate is too high, the instantaneous pressure drop due to the acceleration of vaporization temporarily exceeds the existing static pressure, resulting in unstable temporary reverse current and possible damage to the wetted heat transfer surface. This can lead to clogging of the heat transfer surface. When the heat flux rate is below 6000 BTU hour ^-1 ft ^-2 (162750 kcal / m ² · hour) and within the ratio of the mass of circulating concentrate to the mass of steam less than 300, there is an area where liquid and steam can coexist with stable operation of the system while maintaining the surface of the heat exchanger on the evaporating part of the evaporator is completely wetted, without any risk of clogging or scale formation.

References to points A-D are also provided in FIG.

Fig. 8 illustrates a vertical section through a highly efficient heat exchanger 34, known to those skilled in the art as a plate-frame heat exchanger, in which rows of vertically stacked plates with gaskets 60 are located between two solid frames 62, 64. Such devices are well known for their compactness and ability to have very high U values or overall heat transfer coefficients. This type of heat exchanger, having a configuration that provides a single passage with a counterflow, is very well suited to the present invention and offers the following advantages in the implementation of the present invention.

1. The plate-type heat exchanger offers a low fixed static head and a very low pressure drop across the circulating concentrate fluid or evaporating side, while providing a relatively high heat transfer coefficient.

2. The heat flux can be easily controlled by adding a larger area or plates within the given framework framework.

3. The condensing side of the plate-frame structure is freely drained and has a low pressure drop, while maintaining a relatively high heat transfer coefficient.

4. Highly efficient heat transfer coefficient enables surface temperatures to very close to the temperatures of both fluid flows, reducing the risk of clogging.

5. High turbulence and equivalent high fluid flow rates provide low clogging and keep solids homogeneously suspended as they pass through the heat exchanger.

6. There are no hot or cold places and there are no areas with a fixed flow inherent in the plate-frame construction, which reduces the risk of clogging or scale formation.

7. The plates are smooth and well processed, which reduces the risk of clogging.

8. The short residence time of the fluid reduces the risk of sedimentation, since there is not enough time to achieve equilibrium and the formation of scale-forming pollutants.

In general, the plate-type heat exchanger is very compact and economical with special alloy plates that are resistant to fluid-induced corrosion and stress corrosion cracking, which is typical for salt removal applications. Other heat exchangers, such as a pipe in a shell, a pipe in a pipe, such as a finned pipe, a spiral type, can also be considered by specialists, subject to the specific requirements of the present invention.

Fig.9 is a graph of the mass flow of the circulating concentrate and the mass flow of steam, illustrating the preferred design ratios, generally indicated 66. The desired range from 10 to 100 provides a vapor fraction from less than 10% to about 1%.

Figure 10 presents a graph showing the effect on the local concentration coefficient (CC) of the CC of the _{heat exchanger} depending on the risk of further supersaturation and the formation of sediment in the framework of the heat exchanger. The concentration coefficient of the system can be expressed by the following general equation:

QC _total. = CC of the _{evaporated stream} · CC of the _{heat exchanger}

A concentration reaching a steady state in a heated separator is obtained by continuously removing steam in balance with a continuous steam stream from the heated separator. The value of QC _total. typically of the order of less than 5 to about 20 times, depending on the level and type of contaminants in the incoming stream. Also, depending on the level of the mass of steam leaving the evaporator, the resulting _{heat exchanger} CC (between 1.0 and 1.1) is determined and the evaporated flow rate is controlled so that the desired concentration levels are not exceeded in the evaporator. A typical example is shown below:

The incoming stream contains 20,000 solid dissolved substances and it is desirable that the concentrate contains no more than 100,000 solid dissolved substances.

It was determined that the most effective mass ratio is 20, which gives 5% of the vapor fraction, based on Fig.7.

The QC of the _{heat exchanger} determined from Fig. 8 is 1.07. It is calculated that the _total QC is (100000/20000) = 5.

It is calculated that the CC of the _{evaporated stream} is (5 / 1.07) = 4.7.

Therefore, the adjusted speed of the evaporated stream should be (1 / 4.7) = 21% of the incoming stream.

Therefore, by using the steam recompression and exhaust energy recovery method in combination with a forced convection heat transfer system and observing the steps of carefully selecting the ratio of the mass flow of the circulating system to the mass of the steam flow so that it is less than 300 to about 2, more specifically, a ratio of about 10 to 100, selection of a heat flux of less than 600 BTU hour ^-1 ft ^-2 (1627.5 kcal / m ² · hour), and regulation of the evaporated flow to achieve the desired concentration coefficient, as a result very An efficient water distillation unit that does not become clogged or scale during a long period of use. By combining two well-known methods schemes and incorporating a scheme for extracting waste heat with a unique heat exchange configuration and, more specifically, by calculating a specific ratio of circulating concentrate, which was not indicated in the prior art, the present invention provides an effective method for distilling water so that it does not contain contaminants without the risk of clogging or scale formation.

The following examples serve to illustrate the invention.

EXAMPLE 1

This example calculation is a means of demonstrating the heat balance around the evaporator-heat exchanger. An example is the calculated basis of a distillation unit designed to extract 53,000 US gallons per day (200622 liters) of pure distillate from a contaminated source.

Heat exchanger data:

Surface Area 3,200 ft ² (2,973 m ² )

Type - Plate-frame with

gaskets

U - 542 BTU hour ^-1 ft ^-2 F ^-1 (2637

kcal / m ² C · hour)

The adjusted logarithmic value of the temperature differential is 10.40 ° F

The calculated operating mode is (3,200) · (542) · (10,40); 18041224 BTU hour ^-1 ; (454638 kcal / hour)

Calculated heat flow - (18041224) / (3200); 5638 BTU hour ^-1 ft ^-2 ; (15190 kcal / m ² · hour)

Condensing side

Inlet conditions - 289 ° F at 21.0 psi (abs) (superheated) (142.78 ° C at 1.5 kg / cm ² )

Output conditions - 231.8 ° F at 20.9 psi (abs) (111 ° C at 1.4 kg / cm ² )

Condensation saturation temperature - 232.0 ° F at 21.0 psi (abs) (111.11 ° C at 1.5 kg / cm ² )

The latent heat of condensation - 957,4 BTU lb ^-1 (531 kcal / kg) at 21.0 lb / square inch (absolute) (1.5 kg / cm ²⁾

Water vapor flow - 36.7 US gallons per minute = 18352 pound hour ^-1 (8331.8 kg / hour)

Q _{lowering the temperature of superheated steam} - (18352) · (0.45) · (289-232) 471131 BTU hour ^-1

Q _condensation - (18041224-471131); 17570093 BTU hour ^-1 (4427663 kcal / hour)

The calculated stream is (17570093) / (957.4); 18352 pound hour ^-1 (8331.8 kg / hour)

Evaporation side

Inlet conditions - 212.2 ° F at 18.0 psi (abs) (100 ° C at 1.27 kg / cm ² )

Output conditions - 213.6 ° F at 15.5 psi (abs) (100.5 ° C at 1.08 kg / cm ² )

The latent heat of vaporization is 968.9 BTU hour ^-1 at 15.5 psi (243 kcal / hour)

Circulating ratio

mass to mass of steam - 10

Concentrate circulation rate - 370 US gallons per minute (1400 l / min) 184926 lb-hr ^-1

Steam flow - 18352 pound hour ^-1 (8331.8 kg / hour)

Percentage of steam - (18352/184926) = 10%

Q _evaporation (18352) · (968.9); 17782238 BTU hour ^-1 (4481124 kcal / hour)

Q _detected - (18492 6) · (1.0) · (213.6-212.2); 258896 BTU hour ^-1 (65242 kcal / hour)

Q _total - (17782328) + (258896); 18041224 BTU hour ^-1 (4546388 kcal / hour)

This example shows that a 10% vapor fraction generated in a circulating fluid captures 99% of the heat transferred from the condensing side and increases the temperature of the circulating fluid by about 1 ° F, even if it is 10 times less than the mass of the circulating fluid .

EXAMPLE 2

A plant of this type was designed to recover 10,000 US gallons (37,853 l) per day of pure distillate from a stream to be cooled from a land-based lagoon. The installation was tested over a long period of time and during this period detailed data on the operation of the installation were collected. The pilot plant worked successfully for four months and during the test the clogging in the evaporator and separator was negligible. The equipment used in the pilot test included a Spencer ^TM model GF36204E blower-compressor, providing a pressure drop of 3.0 psi. During the test, plate-frame heat exchangers with one standard passage were used.

The characteristics of the salt-containing inlet stream, concentrated stripped stream, and processed outlet stream were as follows:

Note (1) - pH adjustment before processing to control ammonia.

Note (2) - presents the average values for the test period.

The effluent is of such a quality that it can be discharged into ground water surfaces, since its quality exceeds all established requirements. Compressor energy consumption was measured and recorded at various times of operation, including conditions for power reduction and recycling. The measured energy consumption is shown graphically in FIG. 10 as an energy consumption per 1000 US gallons (3,785.3 L) for various distillate streams. The test data curve was corrected for compressor inefficiency for some flows, and a uniform energy consumption of 50 kWh / 1000 US gallons was obtained. Based on a standard compressor efficiency of 77%, the energy required for a highly efficient distillation plant is about 65 kWh / 1000 US gallons. The amount of evaporated stream on average is 10% of the incoming stream during the test period, which gives an average concentration coefficient (CC) of 10. After the tests, visual observation showed no signs of scale formation in the heated separator and evaporator.

12 shows another embodiment of the present invention. In this embodiment, the superheated steam stream of saturated brine 140 is received from the steam separator 130 in FIG. 1 and transferred to a highly efficient water distillation unit 180.

The stripped stream 140 is flash-vaporized in a low pressure separator 200 to form a low pressure waste energy stream 203 (typically 10-50 psi) (0.703-3.515 kg / cm ² ) and a concentrated low pressure stripped stream 235. The waste energy stream 203 is passed through an evaporator-heat exchanger 205, condensed to distilled water, and collected in surge tank 215.

The concentrated vaporized high pressure stream 235 is heat exchanged with 240 to preheat the produced water 175 to obtain 245. The cooled concentrated vaporized stream is discharged to eliminate waste in the form of stream 185. Waste energy 203 from the stream is transferred to the circulating concentrate from the heated separator, where by controlling the ratio of the circulating mass to the steam stream so that it is in the range from less than 300 to about 1, less than 50% of the steam, or more precisely, less than 10% of the steam forms I am in the circulating concentrate stream leaving the evaporator 230. The steam generated in the circulating stream absorbs the latent heat of vaporization, while at the same time preventing the temperature in the circulating concentrate from rising by more than 1 ° F, while maintaining the effective average logarithmic value of the temperature differential without temperature crossings in the evaporator-heat exchanger 205.

The circulating concentrate is removed at a controlled speed at position 265 using a pump 270 and replaced at position 243 with a portion of the produced formation water 241. The heated portion of the produced water 244 is again connected to the bulk of the heated formation water 245 before entering the heated separator 250.

If the amount of waste energy 203 for a particular oil well is less than that necessary to distill the produced water stream 245, which needs to be cleaned, then a separate circuit is provided including a compressor 305 and an evaporator 315. With the same ratio of circulating mass to steam flow, from less than 300 to about 2, less than 50% of the vapor, or more specifically, less than 10% of the vapor is generated in the circulating concentrate stream leaving the evaporator 350.

Excess steam obtained from a heated separator 250 is usually condensed using an external condenser 355. Energy can be converted to accumulate heat or as heat in other processes, where appropriate. Condensed water streams 320, 360 are collected in condensate equalization tanks 325, 365 and then combined using pumps 220, 330, 375 to form an incoming recycle distilled water stream for steam generators 125. Using the above method, more than 85% water recovery can be obtained.

If non-condensable volatiles are formed during condensation occurring in streams 210, 320, 360, then steam can be automatically vented using means 217, 335 and 370, respectively.

The operating pressure and the corresponding temperature of the heated separator are selected over a wide range from full vacuum to less than 50 psi (3.515 kg / cm ² ), more typically, pressure is selected slightly above or below atmospheric, 12 psi (abs ) (0.844 kg / cm ² ) vacuum to an overpressure of 2 psi (0.141 kg / cm ² ).

On Fig presents another embodiment of the present invention. In this embodiment, part of the waste heat energy 202 from position 200, and / or excess water vapor 255 is used as an energy source for the crystallizer 405 by means of a heat exchanger 400 and a pumping circuit 415, 420. The crystallizer operates at boiling temperature at least at 10 ° F, and most preferably, from 20 ° F to 30 ° F lower than the temperature of the water vapor from the heated separator 250. The mold can operate at a pressure equal to, above or below atmospheric pressure. In the case where the amount of energy in the waste energy stream 202 and / or excess steam 255 exceeds the amount required for the operation of the crystallizer, then condensation can be carried out using external condensing means.

The concentrated stripped stream 275 and the heated separate stream of concentrate 265 are supplied to the crystallizer feed tank 280. The nearly saturated brine is transferred via the feed pump 425 to the circulating loop of the crystallizer 410. The slipping flow of the circulating slurry at position 410 is removed by pump 435 and passed through device 440 separation of solids and liquids or directly transferred to a reservoir for evaporation. A typical solid-liquid separation device familiar to those skilled in the art may include a filter, filter press, gravity sump, clarifier, cyclone separator, decanter and centrifuge.

The filtrate 450 is recycled to the crystallizer feed tank 280. Solid material 445 exiting the solids and liquids separator 440 is collected in suitable storage media and transported to eliminate waste. Any excess water containing contaminants collected in storage areas 455 or in the evaporation pool can be recycled to a feed 280 by using a pump 460.

Condensed water streams 210, 407, and 490 can be collected and combined to produce a recycled stream of distilled water for supply to steam generators 125. Using the above method, 100% water recovery and zero discharge are achieved.

As for the equipment used in this system, specialists in this field will easily determine which of the heated separators, heaters, pump evaporators, compressors / blowers, crystallizers, etc. better to use. Other modifications may be approved without departing from the scope and scope of the invention.

Although embodiments of the invention have been described above, it is not limited to them, and it will be understood by those skilled in the art that various modifications form part of this invention if they are not a departure from the idea, essence and scope of the claimed and described invention.

Claims (40)

1. The method of producing energy for water treatment, used in the extraction of crude oil from an oil reservoir containing crude oil and water, characterized in that it contains the following stages: a) ensuring the incoming flow of water; b) processing the incoming water stream to form a vapor fraction and a liquid fraction; c) the use of a steam separator to separate the vapor fraction and the liquid fraction; d) separation of the vapor fraction and the liquid fraction; e) use of a water distillation unit; e) injection into the oil reservoir of the vapor fraction; g) the collection of crude oil and at least produced water or steam from the oil reservoir; h) separation of crude oil and produced water; i) obtaining thermal energy contained in at least a liquid fraction or a vapor fraction; j) the use of thermal energy for distillation of water. 2. The method according to claim 1, characterized in that the thermal energy contained in the liquid fraction is obtained and used for distillation of water. 3. The method according to claim 1, characterized in that the thermal energy contained in the vapor fraction is obtained and used for distillation of water. 4. The method according to claim 1, characterized in that they reduce the pressure of crude oil, produced water and steam extracted from the oil reservoir, while thermal energy is obtained from the vapor fraction by flash evaporation and the resulting energy is used to distill water. 5. The method according to claim 1, characterized in that the crude oil and the liquid fraction are separated in an oil and water separator. 6. The method according to claim 1, characterized in that the incoming water stream is conditioned before it is contacted with a steam generator. 7. The method according to claim 2, characterized in that the incoming water stream is conditioned to remove mineral impurities. 8. The method according to claim 1, characterized in that the crude oil from stage h) has a density of from 7 ° to 20 ° on a scale of the American Petroleum Institute. 9. The method according to claim 1, characterized in that the incoming water stream contains ground water or produced water. 10. The method according to claim 1, characterized in that it additionally receive thermal energy contained in the liquid fraction and the vapor fraction, and use thermal energy to distill the water. 11. The method according to claim 10, characterized in that it is further treated with produced water by distillation of water. 12. The method according to claim 1, characterized in that it further utilizes a heat exchanger to obtain at least a portion of the thermal energy in the liquid fraction. 13. The method according to p. 12, characterized in that it further warms up the incoming water stream using at least part of the energy received from the heat exchanger. 14. The method according to claim 1, characterized in that the extraction of crude oil includes gravity drainage production using steam or cyclic stimulation with steam or pushing steam and gas. 15. A method of producing energy from equipment for the extraction of crude oil contained in an oil reservoir, wherein energy for processing water is obtained by extracting crude oil, wherein said method is characterized in that it comprises the following steps: a) using a steam source having a vapor fraction and a liquid fraction; b) the use of an oil and water separator and a water distillation unit; c) injecting into the oil reservoir at least a vapor fraction or a liquid fraction to recover crude oil; d) collection of crude oil and water from the oil reservoir in the oil and water separator; e) separation of crude oil and produced water in a separator; f) supply of thermal energy contained in the liquid fraction to the water distillation unit; g) treatment of produced water in a water distillation unit. 16. A method of producing energy for water treatment used in the extraction of crude oil from an oil reservoir containing crude oil and water, comprising the following steps: a) ensuring the incoming flow of water; b) processing the incoming water stream to form a vapor fraction and a liquid fraction; c) the use of a steam separator and the separation of the vapor fraction and the liquid fraction; d) the use of an oil and water separator; d) injection into the oil reservoir of the vapor fraction; f) obtaining crude oil and produced water from the oil reservoir in the oil and water separator; g) supplying thermal energy contained in at least the produced water or the liquid fraction or the vapor fraction to the distillation unit; h) treatment of produced water in a distillation unit. 17. The method according to p. 16, characterized in that the thermal energy from stage g) is obtained from the vapor fraction, and additionally, excess heat is recirculated from the thermal energy obtained from the vapor fraction at stage g) to be injected into the oil reservoir. 18. The method according to clause 16, characterized in that in step e) steam is produced together with crude oil and produced water from the oil reservoir and additionally flash vapor is vaporized in a degassing separator, and heat energy in step g) is selectively obtained from steam, and additionally carry out storage of conditioned and distilled water from the distillation unit. 19. The method according to clause 16, characterized in that the incoming water stream contains ground water or produced water. 20. The method according to clause 16, characterized in that they use a heat transfer agent and a heat transfer medium to transfer the received heat energy to the distillation unit. 21. The method according to clause 16, wherein the resulting crude oil has a density of from 7 to 20 ° on a scale of the American Petroleum Institute. 22. The method according to clause 16, wherein the crude oil production includes gravity drainage production using steam or cyclic stimulation with steam or pushing steam and gas. 23. The method according to clause 16, wherein the thermal energy in step g) is obtained from the vapor fraction, and the pressure of the vapor fraction exceeds the pressure required for injection into the oil reservoir. 24. The method according to 17, characterized in that the vapor fraction has a pressure suitable for injection into the oil reservoir. 25. The method according to item 23, wherein the pressure values of the vapor fraction are in the range from 1900 to 2400 pounds per square. inch. 26. The method according to paragraph 24, wherein the pressure values of the vapor fraction are in the range from 1200 to 1700 psi. inch. 27. The method according to clause 16, wherein the thermal energy is obtained from the liquid fraction and fed into the heat exchanger to heat the incoming liquid stream. 28. A method of obtaining energy in the processing of crude oil for processing water obtained from the extraction of crude oil, characterized in that it contains the following stages: a) providing a purge flow of high pressure; b) instantaneous evaporation of the high pressure purge stream to form a low pressure spent energy stream and a concentrated purge stream; c) evaporation of produced water using a stream of waste energy of low pressure; g) pre-heating the incoming stream of formation water using a concentrated purge stream; e) providing a fluid circulation circuit including a heated separator and a heat exchanger evaporator communicating through a fluid stream; e) passing a preheated incoming stream of formation water into a heated separator; g) passing the spent energy to the evaporator; h) evaporation of the flow of produced water using the spent energy in the evaporator-heat exchanger to form a vapor fraction and a concentrated liquid fraction containing contaminants; i) the circulation of at least part of the concentrated liquid fraction through the evaporator-heat exchanger and a heated separator to maintain the ratio of the mass of the concentrate to the vapor fraction from 300 to 2, to obtain a vapor fraction from about 1 wt.% to less than 50 wt.%, leaving the evaporator-heat exchanger to prevent clogging and scale formation in the evaporator; j) condensation of the vapor fraction by external means of condensation; k) collecting a fraction of the condensed vapor and the waste energy stream, essentially free of contaminants. 29. The method according to p. 28, characterized in that the compressor is selectively used to condense part of the vapor fraction to distilled water when the amount of waste energy is sufficient for the heated separator. 30. The method according to p. 28, characterized in that the steam fraction is passed into the crystallizer of solids to extract energy contained in the vapor fraction, for the formation of solid pollutants in the mold from non-volatile compounds present in the concentrated liquid fraction containing contaminants. 31. The method according to p, characterized in that the vapor fraction is passed into an external condenser to condense the vapor into a liquid. 32. The method according to p. 28, characterized in that the amount of waste water containing impurities processed in this method is equivalent to the amount of waste energy obtained by this method. 33. The method according to p, characterized in that the incoming stream is pre-treated before pre-heating. 34. The method according to p, characterized in that the pre-treatment of the stream is filtration, or ion exchange, or gravitational separation, or chemical treatment, or steaming. 35. The method according to p, characterized in that it further carry out the subsequent processing of the condensed distillate. 36. The method according to clause 35, wherein the subsequent processing is filtration, or ion exchange, or in-depth oxidation, or adsorption, or aeration. 37. The method according to p, characterized in that the mass contains about 10 wt.% The concentration of steam. 38. The method according to p, characterized in that the steam is condensed in a plate type heat exchanger. 39. A method of producing energy in the processing of crude oil for processing water obtained from the extraction of crude oil, characterized in that it contains the following stages: a) providing a purge flow of high pressure; b) instantaneous evaporation of the high pressure purge stream to form a low pressure spent energy stream and a condensed purge stream; c) evaporation of produced water using a stream of waste energy of low pressure; g) pre-heating produced water using a concentrated purge stream; d) providing a circuit for the circulation of the fluid, including communicating heated separator and evaporator-heat exchanger; f) providing a steam circulation circuit including interconnected heated separator, compressor and evaporator-heat exchanger; g) passing the pre-heated produced water into the heated separator; h) evaporation of preheated formation water using a low pressure waste energy stream in a heat exchanger evaporator to form a vapor fraction and a concentrated liquid fraction; i) treatment of the vapor fraction formed by the low pressure waste energy using external condensation means; j) extracting the remaining amount of the vapor fraction using a compressor; k) the circulation of at least part of the concentrated liquid fraction through the evaporator-heat exchanger and the heated separator to maintain the mass ratio of the concentrate to the vapor fraction from 300 to 2 to obtain a vapor fraction from about 1 wt.% to less than 50 wt.%, leaving from the evaporator-heat exchanger, to prevent clogging and scale formation in the evaporator-heat exchanger; m) collecting the condensed fraction of the vapor and the flow of waste energy, essentially free of contaminants. 40. A method of producing energy in the processing of crude oil for processing water obtained from the extraction of crude oil, characterized in that it contains the following stages: a) providing a purge flow of high pressure; b) instantaneous evaporation of the high pressure purge stream with the formation of a low pressure spent energy stream and a concentrated purge stream; c) evaporation of produced water using a stream of waste energy of low pressure; g) pre-heating produced water using a concentrated purge stream; e) providing a fluid circulation circuit including a heated separator and a heat exchanger evaporator communicating with the aid of a fluid stream; e) passing the incoming stream of produced water into the heated separator; g) passing the flow of waste energy of low pressure into the evaporator; h) evaporation of produced water by means of a low pressure waste energy stream in a heat exchanger evaporator with the formation of a first vapor fraction and a concentrated liquid fraction containing contaminants; i) the circulation of at least part of the concentrated liquid fraction containing contaminants through the evaporator-heat exchanger and a heated separator to maintain the mass ratio of the concentrate to the vapor fraction from 300 to 2 to obtain a vapor fraction from about 1 wt.% to less than 50 wt.%, leaving the evaporator-heat exchanger, to prevent clogging and scale formation in the evaporator; j) the use of crystallization means and an evaporator-heat exchanger communicating by means of a vapor fraction; k) removing part of the concentrated liquid fraction containing contaminants for feeding into the crystallization means; m) passing the vapor fraction into the evaporator to provide thermal energy for the deposition of solids from the concentrated liquid fraction containing contaminants; m) creating a second vapor fraction from the crystallization means and a stream of a substantially solid fraction; o) condensation of the second fraction of the vapor by means of condensation; o) collecting the condensed first vapor fraction, the condensed second vapor fraction, and the condensed waste energy stream.

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