CN214880964U - Treatment device for oilfield produced water - Google Patents

Abstract

An embodiment of the utility model provides a processing apparatus of oil field produced water, this processing apparatus of oil field produced water includes: an oilfield produced water providing component configured to provide oilfield produced water; the heat exchange component is configured to carry out cooling treatment on the oilfield produced water; the purification component is configured to purify the oilfield produced water subjected to cooling treatment to obtain produced water; the water conveying pipe is configured to convey the produced water, wherein the first end of the heat exchange component is connected with the oilfield produced water supply component, and the second end of the heat exchange component is connected with the water conveying pipe, so that the oilfield produced water and the produced water are subjected to heat exchange in the heat exchange component to be subjected to cooling treatment on the oilfield produced water, and therefore heat exchange between the oilfield produced water with high temperature and the treated clean produced water can be realized, cooling without an external cold source is not required, and waste heat recycling is realized.

Description

Treatment device for oilfield produced water

Technical Field

The embodiment of the utility model relates to a processing apparatus of oil field produced water.

Background

The thick oil exploitation is a complex process, and the difficulty and the cost of thick oil exploitation are high. The thickened oil thermal recovery is the most effective and widest application range method for improving the thickened oil recovery efficiency at present, and mainly comprises the modes of steam huff and puff, steam drive, steam assisted gravity drainage and the like. During heavy oil thermal recovery, high-temperature and high-pressure steam needs to be continuously added into a stratum to reduce the viscosity of crude oil, and a large amount of fresh water and heat energy are consumed in the process.

The thick oil produced water has the characteristics of high mineralization degree, high temperature, high hardness, easiness in forming oil-in-water emulsion, small oil-water density difference, high silicon content, high pollutant content and the like. A large amount of surplus sewage is ineffectively recharged in the process of heavy oil thermal recovery, the ecology of the area where the heavy oil reservoir is located is fragile, if the produced water of the heavy oil is directly discharged into the external environment, the ecological environment can be damaged, the waste of water resources can be caused, and great negative effects are caused on the water balance of the oil field. The oil field production situation is increasingly severe, the clear water resource is increasingly in short, the redundant thick oil produced water is treated to the recyclable standard, the important significance is provided for the ecological environmental protection of the oil field, and the water resource can be saved.

SUMMERY OF THE UTILITY MODEL

The utility model discloses an at least embodiment provides a processing apparatus of oil field produced water, and this processing apparatus of oil field produced water includes: an oilfield produced water providing component configured to provide oilfield produced water; the heat exchange component is configured to carry out cooling treatment on the oilfield produced water; the purification component is configured to purify the oilfield produced water subjected to cooling treatment to obtain produced water; the water conveying pipe is configured to convey the produced water, wherein the first end of the heat exchange component is connected with the oilfield produced water supply component, and the second end of the heat exchange component is connected with the water conveying pipe, so that the oilfield produced water and the produced water are subjected to heat exchange in the heat exchange component, and the oilfield produced water is subjected to cooling treatment.

For example, in at least one embodiment of the present invention, there is provided a processing apparatus, wherein the heat exchange member includes a heat exchanger.

For example, at least one embodiment of the present invention provides a treatment device, further comprising a heat sink, wherein the heat sink is configured to dissipate heat from the oilfield produced water.

For example, at least one embodiment of the present invention provides a treatment apparatus, further comprising a cooling tower, wherein the cooling tower is disposed between the heat exchanging component and the purifying component.

For example, in at least one embodiment of the present invention, the purification unit includes at least one of an oxidation tank, a biological aerated filter, an ultrafiltration element, a reverse osmosis element, and a resin filter.

For example, in the processing apparatus provided in at least one embodiment of the present invention, the oxidation pond includes an electrocatalytic oxidation component, or a combination of ozone and hydrogen peroxide, or an electrocatalytic oxidation component, and a combination of ozone and hydrogen peroxide.

For example, in the treatment device provided by at least one embodiment of the present invention, the filler in the biological aerated filter is at least one of coconut shell carbon, apricot shell carbon and coal-based activated carbon.

For example, the utility model provides a processing apparatus, still include pretreatment components, wherein, pretreatment components includes at least one of equalizing basin, nitrogen gas air supporting unit, except that hard silicon removal unit, sedimentation tank and filter unit.

For example, in at least one embodiment of the present invention, the filtering unit includes a membrane-coated fiber ball filter and a tubular microfiltration membrane filter.

Drawings

In order to illustrate the technical solutions of the embodiments of the present invention more clearly, the drawings of the embodiments will be briefly described below, and it is obvious that the drawings in the following description only relate to some embodiments of the present invention, and are not intended to limit the present invention.

Fig. 1 is a flow chart of a method for treating oilfield produced water according to an embodiment of the present invention;

fig. 2 is a process diagram of a treatment method for oilfield produced water according to an embodiment of the present invention;

fig. 3 is a flow chart of a pretreatment process according to an embodiment of the present invention;

fig. 4 is a flow chart of a method for treating oilfield produced water according to an embodiment of the present invention;

fig. 5 is a schematic view of a connection structure of a treatment device for oilfield produced water according to an embodiment of the present invention;

fig. 6 is a schematic view of a connection structure of another treatment device for oilfield produced water according to an embodiment of the present invention; and

fig. 7 is a schematic structural diagram of a nitrogen gas floatation formation according to an embodiment of the present invention.

Detailed Description

In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the drawings of the embodiments of the present invention are combined below to clearly and completely describe the technical solution of the embodiments of the present invention. It is to be understood that the embodiments described are only some of the embodiments of the present invention, and not all of them. All other embodiments, which can be obtained by a person skilled in the art without any inventive work based on the described embodiments of the present invention, belong to the protection scope of the present invention.

Unless defined otherwise, technical or scientific terms used herein shall have the ordinary meaning as understood by those of ordinary skill in the art to which the invention belongs. The use of "first," "second," and similar terms in the description herein do not denote any order, quantity, or importance, but rather the terms are used to distinguish one element from another. The word "comprising" or "comprises", and the like, means that the element or item listed before the word covers the element or item listed after the word and its equivalents, but does not exclude other elements or items. The terms "connected" or "coupled" and the like are not restricted to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "upper", "lower", "top", "bottom", and the like are used merely to indicate relative positional relationships, and when the absolute position of the object being described is changed, the relative positional relationships may also be changed accordingly.

The steam injection boiler water has high requirement on salt content, and the treatment technology for reusing the oilfield produced water as the steam injection boiler water mainly comprises two modes of thermal treatment and membrane treatment. The thermal method treatment technology adopts an evaporation desalination mode to recover distilled water, and adopted equipment comprises a Mechanical Vapor Recompression (MVR), a Mechanical Vapor Compressor (MVC) or a multi-effect evaporator and the like. By adopting the method, more than 80% of high-quality distilled water can be recovered. In addition, the recovery rate of distilled water is related to the content of salt in the oilfield produced water, and the higher the concentration of salt in the treated oilfield produced water is, the higher the energy required for evaporation is, the higher the latent heat of vaporization of water is, and the higher the energy required for the phase change of water from liquid state to gas state is. That is, the thermal treatment technique needs to consume a large amount of steam for heating or electric energy for heating, the treatment cost is high, and the volume of the used equipment is large. In addition, the chlorine content and the salt content in the produced water of the oil field are high, and the material requirement on an evaporation device which runs at high temperature is extremely high when the produced water of the oil field is treated, so that the thermal treatment technology has higher equipment investment and running cost. The membrane treatment technology is significantly lower than the thermal treatment technology in terms of treatment cost and equipment investment, main equipment adopted by the membrane treatment technology comprises an ultrafiltration membrane (UF), a nanofiltration membrane (NF), a reverse osmosis membrane (RO) and the like, and the membrane components generally bear a limit temperature of 45 ℃, so that the membrane components are damaged when the oilfield produced water is treated at a higher temperature. The temperature of the oilfield produced water, for example, the thick oil produced water is basically about 70 ℃, so that the temperature of the oilfield produced water needs to be reduced to below 35-45 ℃, and then the membrane modules can normally operate when the cooled oilfield produced water is treated.

The utility model discloses an inventor notices, present embrane method treatment mode is the process of heat dissipation cooling only, the unable recycle of heat energy, can be at the in-process that falls 35 ~ 45 ℃ to about 70 ℃ with the temperature of oil field extraction water, carry out recycle to this part heat energy, the clean product water that is about to follow-up pending high temperature oil field extraction water and the oil field extraction water of handling obtains carries out the heat exchange, the oil field extraction water of high temperature that has not only realized not needing external cooling source to follow-up pending lowers the temperature and has realized the waste heat retrieval and utilization again, thereby energy saving and emission reduction has been realized.

At least one embodiment of the utility model provides a treatment method of oil field produced water, this method includes: providing oilfield produced water; cooling and purifying the oilfield produced water to obtain produced water; and carrying out heat exchange on the subsequent oilfield produced water and the produced water so as to reduce the temperature of the subsequent oilfield produced water and increase the temperature of the produced water.

For example, fig. 1 is a flowchart of a method for treating oilfield produced water according to an embodiment of the present invention, including the following steps:

step S01: providing oilfield produced water.

For example, the oilfield produced water is heavy oil produced water. In the process of thick oil recovery, a thermal recovery boiler is needed to inject steam for recovery, namely high-temperature high-pressure steam is continuously added into a stratum to reduce the viscosity of crude oil, so that the temperature of thick oil produced water before treatment is usually about 70 ℃, and in addition, the thick oil produced water has the characteristics of high viscosity of produced liquid, large sand carrying capacity, high hardness and high mineralization degree.

Step S02: cooling and purifying the produced water of the oil field to obtain the produced water.

In this step, an external cooling source is required to cool the initial oilfield produced water.

Step S03: and carrying out heat exchange on the subsequent oilfield produced water and the produced water so as to reduce the temperature of the subsequent oilfield produced water and increase the temperature of the produced water.

For example, steam injection boiler water has a high requirement on salt content, can only be clean water, and needs to have a certain temperature, so that the produced water after the temperature is increased can be reused as gas injection boiler water.

For example, heat exchanging oilfield produced water and produced water includes: and the heat exchange part is adopted for heat exchange, so that the temperature of the oilfield produced water is reduced, and the temperature of the produced water is increased. For example, the first end of the heat exchange part is connected with a pipe fitting for inputting oilfield produced water, the second end of the heat exchange part is connected with a water conveying pipe for conveying produced water, the oilfield produced water and the produced water flow reversely, so that the oilfield produced water and the produced water exchange heat in the heat exchange part to cool the oilfield produced water, and the temperature of the produced water is increased to prepare for gas injection boiler water.

For example, heat exchange component includes spiral plate heat exchanger or plate heat exchanger, and this heat exchange component includes high-efficient plate heat exchange equipment, and this high-efficient plate heat exchange equipment is detachable, can realize the convenience of installation, transportation etc. like this. The high-efficiency plate type heat exchange equipment is made of titanium alloy materials, such as titanium steel alloy, so that the high-efficiency plate type heat exchange equipment can bear the temperature of 500-550 ℃.

For example, fig. 2 is a process diagram of a treatment method of oilfield produced water according to an embodiment of the present invention, as shown in fig. 2, after heat exchange is performed by using a heat exchange component, the method further includes: and a radiator is adopted for radiating.

For example, adopt the radiator can carry out further cooling to oil field produced water to reduce the follow-up risk of causing the damage to milipore filter (UF), nanofiltration membrane (NF) and reverse osmosis membrane (RO), in addition, jointly use heat transfer part and radiator, can reduce the load and the equipment investment of radiator, compare promptly and do not adopt heat transfer part heat transfer, and directly adopt the radiating situation of radiator, can make the load of radiator reduce, make the life-span of radiator not shorten.

For example, as shown in fig. 2, after the heat exchange, the processing method may further include: the cooling tower is adopted to cool the oilfield produced water again, so that the temperature of the oilfield produced water is lower than 35 ℃, and when the oilfield produced water with the temperature lower than 35 ℃ is input into subsequent ultrafiltration membrane (UF), nanofiltration membrane (NF) and reverse osmosis membrane (RO) for treatment, the membrane components cannot be influenced due to too high temperature.

For example, in one example, the cooling tower is a closed cooling tower, the cooling tower uses water as a circulating coolant, the circulating coolant and the oilfield produced water are located in different pipelines, the circulating coolant absorbs heat from the oilfield produced water to reduce the temperature of the oilfield produced water, and the circulating coolant then discharges the heat to the atmosphere to reduce the temperature of the circulating cooling water.

For example, in another example, the cooling tower and the radiator are directly connected to further cool the oilfield produced water, and the cooling tower uses cold-blast cooling.

For example, as shown in fig. 2, the purification treatment of oilfield produced water includes: and oxidizing the oilfield produced water subjected to temperature reduction treatment by using an oxidation pond to decompose at least part of organic matters in the oilfield produced water.

For example, adopt the oxidation pond to oxidize including adopting ozone and hydrogen peroxide solution to oxidize, or adopt the mode of electro-catalysis to oxidize, or can also adopt ozone and hydrogen peroxide solution to oxidize and adopt the mode of electro-catalysis to carry out the combination of the mode of oxidizing, this oxidation can also include fenton oxidation, the embodiment of the utility model discloses a do not limit to this.

For example, decomposing at least part of organic matters in the oilfield produced water comprises decomposing emulsified and dissolved organic matters in the oilfield produced water by using an oxidation pond, so that the pollution and blockage of macromolecular organic matters in the oilfield produced water to a subsequently adopted membrane system are reduced, and meanwhile, the biodegradability of the oilfield produced water is improved.

For example, the conventional pretreatment methods such as oil removal, air flotation, adsorption and filtration cannot greatly remove dissolved and emulsified organic matters, and the Chemical Oxygen Demand (COD) in the produced water of the oil field is still relatively high and is about 400-600 mg/L. High Chemical Oxygen Demand (COD) easily causes the pollution of a membrane treatment system to block, organic pollutants are not easy to backwash, and the membrane flux is not easy to recover after being reduced.

For example, the concentration of ozone in the oxidation pond is 5-30mg/L, and the oxidation time of the oxidation pond is less than or equal to 10 min. After the treatment of this step, the COD (chemical oxygen demand) of the produced water is less than 45 mg/L. For example, ozone thermal oxidation can greatly improve the treatment effect of ozone on refractory organics in oil field produced water.

The embodiment of the utility model provides an oxidation pond has been increased on conventional preliminary treatment's basis, and this oxidation pond can decompose the oil field and produce the organic matter that aquatic dissolved and emulsified to can alleviate the dirty stifled to membrane equipment. The oilfield produced water treated by the oxidation pond enters a biochemical treatment unit to deeply mineralize organic matters, so that the influence of the organic matters on the membrane flux can be further reduced.

For example, the treatment mode of the oxidation pond can be directly used for treating the oilfield produced water, so that the treatment effect of the oilfield produced water can be ensured, the treatment cost can be greatly reduced, the whole process flow is simple, and the operability is strong.

For example, oilfield produced water is treated by an oxidation pond and then enters a biochemical treatment unit, and the biochemical treatment unit can deeply mineralize organic matters so as to further reduce the influence of the organic matters on membrane flux.

For example, as shown in fig. 2, the purification treatment of oilfield produced water includes: and (3) adopting a Biological Aerated Filter (BAF) to perform at least one of decomposition and mineralization treatment on the oilfield produced water to remove organic matters.

For example, a biological aerated filter is filled with plastic honeycomb packing, the packing is immersed in water, and the bottom of the packing is aerated and oxygenated by a blower to carry out blast aeration. The air can entrain the oilfield produced water to be treated from bottom to top and freely passes through the filter material part to reach the ground, and the biological aerated filter returns to the bottom of the biological aerated filter from top to bottom at the filter material interval after the air escapes. The active rock debris is attached to the surface of the filler and does not flow along with water, the biological membrane is directly and continuously updated by the strong stirring of the ascending air flow, and the purification effect is greatly improved. The aerobic treatment process adopts a contact oxidation biomembrane method technology, and can obviously remove soluble organic pollutants and colloidal organic pollutants in the water produced by the oil field.

For example, the biological aerated filter takes loaded granular fillers as carriers and granular fillers and biological membranes attached and grown by the granular fillers as main treatment media, and fully plays the roles of biological metabolism, biological flocculation, physical filtration and the physical adsorption and interception of the membranes and the fillers so as to realize the efficient removal of organic pollutants.

For example, Biological Aerated Filters (BAF) may serve the purpose of filtering suspended matter, as well as reducing the concentration of biodegradable matter.

For example, the biological aerated filter consists of a filter body, a filter material, a supporting layer, a water and gas distribution system, a backwashing system, a water outlet system, an automatic control system and the like; the tank body of the biological aerated filter can be a conventional reactor, the reactor can use fillers, and the scale of the biological aerated filter can be determined according to the quantity of circulating water and the concentration of pollutants in the circulating water. For example, a corresponding control system, power system, monitoring system, etc. may also be provided as desired.

For example, the biological aerated filter is used for decomposing and mineralizing the produced water in an oil field, which is one of the main ways for deeply removing organic pollutants, the traditional biochemical filter occupies a large area, the membrane hanging period is as long as 30-40 days, the aeration amount is large, and the use cost is high. The aeration biological filter tank is used for replacing a traditional biochemical tank, biological oxidation, biological flocculation and filtration are integrated, a secondary sedimentation tank is not required, the biochemical requirement is met, and the purposes of reducing the floor area and the capital investment are achieved. The biological aerated filter has the advantages of high oxygen transmission efficiency, small aeration amount, low oxygen supply power consumption, low power consumption for treating unit oilfield produced water, high automation degree, convenient operation and management and short biofilm formation period of 14-21 days.

For example, the hydraulic characteristics of the large-flow internal circulation flow of the biological aerated filter technology and the characteristics of high mass transfer speed, multiple microorganism types and high activity of the large-flow internal circulation flow rapidly degrade organic matters in the produced water of a high-concentration oil field so as to achieve the purpose of primarily degrading the organic matters in the produced water of the oil field.

For example, the operation time of the biological aerated filter is 24-72 h, such as 24h, 36h, 48h or 72 h. The aeration biological filter tank needs to be backwashed, the backwashing is operated by air-water linkage, and the total time of the backwashing is 1 hour, wherein the total time comprises the backwashing time of 0.5 hour and the recovery time of 0.5 hour. The back flushing air of the internal circulation biological aerated filter adopts non-purified air, the back flushing air pressure is more than 0.45MPa, and the back flushing air quantity is 2-3 times of the treated water quantity.

For example, the supernatant of the sedimentation tank is backwashed with a quantity of backwash water of 1.6 to 2.0 times as much as the quantity of the treated water. For example, the backwash wastewater enters a backwash sedimentation tank for sludge-water separation, and after static sedimentation, the supernatant is used as backwash water for the next backwash.

For example, in the method provided by at least one embodiment of the present invention, before the biological aerated filter is used to decompose and/or mineralize the produced water in the oil field, the method further includes: the method comprises the following steps of activating the filler in the biological aerated filter, wherein the activating the filler in the biological aerated filter comprises the following steps: the method comprises the steps of washing the biological aerated filter with clean water, removing at least one of impurities adsorbed by the filler and powder generated by abrasion of the filler, treating the filler with a sodium hydroxide solution, removing organic impurities contained in the filler, treating the filler to be neutral with clean water, treating the filler with a sulfuric acid solution to remove inorganic matters adsorbed by the filler, and treating the filler to be neutral with clean water.

For example, the filler in the conventional biological aerated filter is directly used, and dust, clay, grease and other pollution can be generated on the filler in the processes of processing, transporting and packaging the filler. The existing processing technology causes that microscopic gaps in the filler are not smooth enough or blocked to a certain extent, so that the adsorption effect of the filter material is poor, the effective specific surface is reduced, and the membrane hanging period is influenced.

For example, the activation process after filling includes: flushing the biological aerated filter with clear water to remove impurities adsorbed by the filler and/or powder generated by abrasion of the filler; treating the filler by using a sodium hydroxide solution to remove organic impurities contained in the filler, and treating the filler to be neutral by using clear water; and (3) treating the filler by using a sulfuric acid solution to remove inorganic matters adsorbed by the filler, and treating the filler to be neutral by using clear water.

For example, in one example, the specific activation process after filling includes: firstly, washing for 2-3 times by using clear water, and washing to remove impurities adsorbed by a filter material and ineffective powder generated by abrasion of the filter material; secondly, cleaning and soaking the filler for 4 hours by using 5% sodium hydroxide to remove grease and organic matters on the surface of the filler; after the sodium hydroxide alkali liquor is emptied, washing the sodium hydroxide alkali liquor to be neutral by using clear water; and thirdly, washing and soaking the filler for 4 hours by using 5% sulfuric acid, acidifying and cleaning the throat gap of the filler, and dissolving impurities adsorbed on the inner part and the outer part of the filler.

For example, the activation process can improve the film forming capacity and the biological adsorption capacity of the filler, and the film forming period can be reduced to 7-14 days.

For example, in one embodiment of the present invention, the filler in the biological aerated filter comprises at least one of coconut shell carbon, apricot shell carbon and coal activated carbon, and the filler in the conventional biological filter comprises at least one of ceramsite, volcanic rock and zeolite. The specific surface area of the filler in the aeration biological filter tank in the embodiment of the utility model is larger than that of the filler in the conventional biological filter tank.

For example, biochemical strains inoculated in the biological aerated filter, which are usually from sewage treatment plants in the market, are not suitable for the high-salt-content working condition in the produced water of an oil field, so that the osmotic pressure in the added microorganisms is changed, the microorganisms are dehydrated and die, and the microbial culture cycle is long, about 90 days, so that the time cost and the economic cost are high.

For example, in an embodiment of the present invention, the method for treating oilfield produced water further comprises: adding salt-tolerant bacteria agents into the biological aerated filter, wherein the mass of the salt-tolerant bacteria agents in each cubic meter of oilfield produced water is 5-50 g, and the effective bacteria number in each gram of salt-tolerant bacteria agents in the oilfield produced water is more than or equal to 2.0 hundred million.

For example, in some examples, the mass of the halotolerant agent per cubic meter of oilfield produced water is 10g, 15g, 20g, 25g, 30g, 35g, 40g, 45g, or 50 g.

For example, the mode of adding the salt-tolerant microbial inoculum is easy to realize, the removal rate of organic matters in the biochemical system can be enhanced, the running condition of the biochemical system in cold seasons is improved, and a newly-built biochemical system is quickly started, for example, a new ecological system can be established in 14-21 days.

For example, as shown in fig. 2, the method for treating oilfield produced water further comprises: and (3) carrying out ultrafiltration treatment on the effluent of the biological aerated filter by adopting an ultrafiltration element. For example, impurities such as suspended matters and colloids can be removed through ultrafiltration treatment of the ultrafiltration element, and deep pretreatment is performed on oilfield produced water entering a subsequent reverse osmosis membrane.

For example, the ultrafiltration forms include, but are not limited to, hollow ultrafiltration membranes, plate-type ultrafiltration membranes, and tubular ultrafiltration membranes, the ultrafiltration membranes are made of, but not limited to, inorganic ceramic membranes, inorganic silicon carbide membranes, organic polyvinylidene fluoride (PVDF), Polytetrafluoroethylene (PTFE), etc., the average pore diameter of the ultrafiltration membranes is 20-200nm, and the flux of the ultrafiltration membranes is, for example, 10-35L/m²H. The mode of adopting ultrafiltration treatment has the advantages of no need of adding medicine, lower operation pressure and stronger operability, and the ultrafiltration treatment can separate macromolecules and viruses.

For example, as shown in fig. 2, at least one embodiment of the present invention provides a method for treating oilfield produced water, further comprising: and (4) carrying out reverse osmosis treatment on the effluent of the ultrafiltration element by using a reverse osmosis element to desalt. For example, the reverse osmosis element comprises a reverse osmosis membrane, the reverse osmosis membrane is in the form of a roll-type membrane reverse osmosis element and a disc-type reverse osmosis element, the salt rejection rate of the reverse osmosis membrane is not lower than 97%, the filtration temperature is not higher than 45 ℃, the operation pressure is 0.1-10MPa, and the flux of the reverse osmosis membrane is 10-25L/m²·h。

For example, as shown in fig. 2, at least one embodiment of the present invention provides a method for treating oilfield produced water, further comprising: treating the concentrated water after reverse osmosis treatment by using a resin filter, setting a filtration speed to be 5BV/h, wherein the produced water is output from the resin filter, the resin filter is used for carrying out ion exchange treatment on the oilfield produced water after reverse osmosis treatment to deeply remove calcium, magnesium and other ions, the resin filter adopts a ceramic membrane cross-flow filter with the average pore size of 50nm for filtration, the pressure is controlled to be 0.3MPa, the membrane surface flow rate is controlled to be 3m/s, the pH of the produced water of the hard filter is adjusted to be 6-9, the SDI of the produced water of the hard filter is less than or equal to 5, and the recovery rate is not less than 95%.

For example, as shown in fig. 2, in the method provided in at least one embodiment of the present invention, before the cooling and purifying treatment of the oilfield produced water, the method further includes: the method comprises the following steps of pretreating oilfield produced water, wherein the pretreatment working section comprises the following steps: treating the oilfield produced water by adopting at least one of a regulating tank, a nitrogen air flotation unit, a hard removal silicon unit, a sedimentation tank and a filtering unit.

For example, fig. 3 is a flowchart of a pretreatment process according to an embodiment of the present invention, and as shown in fig. 3, the pretreatment process includes:

s11: and (4) inputting the oilfield produced water into a regulating reservoir.

For example, the conditioning tank can adjust the acidity and alkalinity of the oilfield produced water, such as by applying sodium hydroxide, sodium carbonate and the like in the sedimentation tank to increase the pH of the originally acidic oilfield produced water to be close to neutral, and also can enable part of calcium ions, magnesium ions and the like to form sediment to be removed. Or, sulfuric acid, hydrochloric acid, nitric acid and the like can be applied to the sedimentation tank to reduce the pH of the originally alkaline oilfield produced water to be close to neutrality, and partial calcium ions, magnesium ions, silver ions and the like can be precipitated to be removed.

S12: and inputting the oilfield produced water output from the sedimentation tank into a nitrogen air flotation unit.

For example, the conventional sedimentation oil removal method has low oil removal efficiency and large occupied area. The oil removal efficiency can be improved by using the air floatation method, suspended matters can be removed at the same time, but the air floatation method introduces dissolved oxygen which can increase the corrosion rate of a water treatment system, and because the produced water of an oil field usually contains hydrogen sulfide and petroleum hydrocarbon substances, the air floatation method accelerates the volatilization of the organic matters, so that peculiar smell exists in the operation environment, and the operation environment is deteriorated. For example, the pretreatment may be performed by using a nitrogen flotation unit, wherein the nitrogen source in the nitrogen flotation unit comprises nitrogen generated by pressure swing adsorption of air source for nitrogen production or a pure nitrogen source.

For example, the problem that the conventional dissolved air flotation introduces dissolved oxygen to increase the corrosion rate can be avoided by adopting nitrogen gas flotation. The top of the nitrogen gas floatation device is designed in a sealing way, a maintenance opening is reserved, a system of gas collecting and introducing pipelines is designed in a matching way, and peculiar smell gas generated by the nitrogen gas floatation is collected into a gas treatment system for treatment. Compared with air floatation, nitrogen floatation not only avoids external oxygen from being blended into oilfield produced water, but also avoids the problem that the electrochemical corrosion of oilfield produced water is aggravated, which is possibly caused by the nitrogen floatation, and can blow off dissolved gases in oilfield produced water, such as aggressive carbon dioxide, dissolved oxygen, hydrogen sulfide and the like, so that the corrosion characteristic of oilfield produced water and the operating environment of a downstream working section can be obviously improved.

For example, the nitrogen gas floatation bearing device is a nitrogen gas floatation oil removal device, the nitrogen gas floatation oil removal device generates a large amount of micro-fine nitrogen bubbles as a carrier through a nitrogen gas generating device in the oilfield produced water to be treated, when oil drops and impurity floc in the oilfield produced water adhere to the bubbles, the particles with the integral density smaller than that of the water are formed, the buoyancy of the particles is larger than the gravity and the resistance to enable the particles to float up to the water surface, so that the separation process of the solid and the solid, the solid and the liquid, and the liquid in the water is completed, and simultaneously, the separated floating oil and the impurity floc are discharged out of the system through a bottom sludge discharge system and a top slag scraping system to further purify the oilfield produced water.

S13: and (4) inputting the oilfield produced water output from the nitrogen air flotation unit into a hardness and silicon removal unit.

For example, the hardness-removing and silicon-removing unit may be subjected to a hardness-removing treatment by a lime softening method, a lime-soda softening method, a lime-gypsum treatment method, a flake soda method, or the like. For water with high hardness and high alkalinity, a lime softening method is generally adopted; the lime-soda softening method is usually adopted for water with high hardness and low alkalinity; negative hard water with low hardness and high alkalinity is treated by a lime-gypsum method.

For example, silicic acid is one of the major impurities in oilfield produced water, primarily resulting from the hydrolysis of silicate minerals. Silicon in water generally exists in a molecular state, an ionic state, a colloidal state or a solid state, and the existing form of silicic acid in water is related to the pH value of water, including dissolved metasilicic acid, ortho-silicic acid and polymerized polysilicic acid. When the pH is not high, the silica dissolved in water is mainly in the form of simple silicic acid in a molecular state, and a silicon compound existing in an ionic or molecular state is called active silicon, which is much smaller in size than colloidal silica, and for example, a desiliconization treatment can be performed by adding a magnesium agent to water together with a coagulant.

S14: and (4) inputting the oilfield produced water output from the hard removing and silicon removing unit into a sedimentation tank.

For example, the sedimentation tank is a radial flow sedimentation tank, and the effluent quality of the sedimentation tank is as follows: COD is 100-350 mg/l, petroleum is 0.2-3 mg/l, and suspended matter is 10-30 mg/l.

For example, the sedimentation tank is any one of a high-efficiency sedimentation tank, a sand-adding sedimentation tank and a circulation clarification tank. Before adopting the sedimentation tank to handle, still including adopting the flocculation basin to handle, the water inlet of flocculation basin links to each other with the delivery port that removes silicon unit firmly, and the delivery port of flocculation basin links to each other with the water inlet of sedimentation tank.

S15: and (4) inputting the oilfield produced water output from the sedimentation tank into a filtering unit.

For example, the pretreatment with a filtration unit may further comprise a microfiltration treatment with a microfiltration unit. The microfiltration treatment can comprise two modes of cross-flow filtration and dead-end filtration, the average pore diameter of a filter membrane adopted in the microfiltration treatment is 20-200nm, and the operating pressure can be 0.01-1 MPa. For example, the form of the microfiltration membrane includes but is not limited to roll type membrane and disc type reverse osmosis membrane element, the desalination rate of the microfiltration membrane is not less than 97%, and the filtration temperature of the microfiltration membrane is not more than 45 ℃. For example, microfiltration can remove suspended matter and bacteria from oil field produced water.

For example, the pretreatment using a filtration unit may further include a nanofiltration treatment using a nanofiltration unit. The nanofiltration unit comprises a primary nanofiltration unit and a secondary nanofiltration unit, when the content of calcium ions in the oil field produced water is lower than 1500mg/L and the total amount of soluble solids is lower than 25000mg/L, the primary nanofiltration membrane is adopted to treat the oil field produced water, and when the content of calcium ions in the oil field produced water is higher than 1500mg/L and the total amount of soluble solids is higher than 25000mg/L, the secondary nanofiltration membrane is adopted to treat the oil field produced water. When the first-stage nanofiltration membrane and/or the second-stage nanofiltration membrane is/are adopted to treat the oilfield produced water, nanofiltration concentrated solution can flow back to the ultrafiltration water inlet pipeline. For example, the nanofiltration treatment can comprise two modes of cross-flow filtration and dead-end filtration, the nanofiltration membrane used in the nanofiltration treatment has an average pore diameter ranging from 10 nm to 20nm, and the operating pressure can be 0.01 MPa to 1 MPa. For example, the nanofiltration membrane adopts membrane elements including but not limited to tubular, plate, hollow fiber, rolled nanofiltration membrane and disc nanofiltration membrane, the rejection rate is not lower than 95%, the temperature of the nanofiltration membrane is not more than 45 ℃, the recovery rate of produced water is 60-90%, the membrane flux is 10-40LMH, and the nanofiltration membrane is made of polyamide. And returning concentrated water generated by nanofiltration filtration to the biological aerated filter for treatment. For example, nanofiltration treatment may reduce the hardness of oilfield produced water and remove a portion of heavy metals and organics.

For example, when the flux of the nanofiltration membrane in the nanofiltration membrane processor is reduced by 15%, the method for cleaning the nanofiltration membrane is carried out according to the following steps: firstly, flushing a nanofiltration membrane by using desalted water, and flushing the nanofiltration membrane for 30 to 60min at the conditions of normal pressure and 20 to 25 ℃ after discharging raw water remained on the nanofiltration membrane; secondly, cleaning the nanofiltration membrane processor for 20 to 40min by adopting a mixed solution of 0.1 percent of ethylenediamine tetraacetic acid, 0.2 percent of sodium pyrophosphate and 0.5 percent of sodium dodecyl sulfate; thirdly, washing the nanofiltration membrane for 20min to 40min by hydrochloric acid with the pH value of 2; and fourthly, washing the nanofiltration membrane by using desalted water until the pH value of the discharged water is neutral, and finishing regeneration of the nanofiltration membrane.

For example, the hardness of the oil field produced water after pretreatment is less than or equal to 200mg/L, the density of silicon is less than or equal to 20mg/L, the density of petroleum hydrocarbon is less than or equal to 2mg/L, and the alkalinity is less than or equal to 2000 mg/L.

For example, fig. 4 is a flowchart of a treatment method for oilfield produced water according to an embodiment of the present invention, the treatment method includes the following steps:

s21, pretreating the oilfield produced water, and then sequentially entering a heat exchange part and a cooling tower.

The step can cool the pretreated oilfield produced water.

And S22, the oil field produced water after being cooled enters an oxidation pond.

For example, the organic matters emulsified and dissolved in the oilfield produced water can be oxidized and decomposed by using the oxidation pond, so that the pollution and blockage of macromolecular organic matters in the oilfield produced water to a subsequently adopted membrane element are reduced, and meanwhile, the biodegradability of the oilfield produced water is improved.

And S23, the oil field produced water after oxidation in the oxidation pond enters the biological aerated filter.

For example, organic matters in the produced water of the oil field are further decomposed and mineralized in the biological aerated filter, so that the pollution and blockage of the membrane are further reduced, and the backwashing water of the biological filter enters a regulating tank of a pretreatment working section.

S24, the effluent of the biological aerated filter enters an ultrafiltration element and a reverse osmosis element.

For example, the ultrafiltration element is used for ultrafiltration to remove impurities such as suspended matters, colloid and the like, and the produced water of the oil field enters the reverse osmosis element for advanced treatment, the reverse osmosis element can realize a desalination function, and the concentrated water generated by the reverse osmosis element is reinjected to the stratum of the oil field.

S25, enabling the concentrated water desalted by the reverse osmosis element to enter a resin filter.

For example, the resin filter uses a cationic resin, and backwash water of the resin filter is discharged to a conditioning tank.

And S26, exchanging heat between the water discharged from the resin filter as a cold source in the heat exchange part and the pretreated oilfield produced water, and then feeding the pretreated oilfield produced water into a steam injection boiler for recycling.

The utility model discloses an at least embodiment still provides a processing apparatus of oil field produced water, for example, figure 5 is the utility model discloses a connection structure schematic diagram of a processing apparatus of oil field produced water that embodiment provided, as shown in figure 5, this processing apparatus of oil field produced water includes: an oilfield produced water supply section 1 configured to supply oilfield produced water; the heat exchange part 2 is configured to carry out cooling treatment on the oilfield produced water; the purification component 3 is configured to purify the oilfield produced water subjected to the temperature reduction treatment to obtain produced water; the water conveying pipe 4 is configured to convey produced water, the first end of the heat exchange part 2 is connected with the oilfield produced water supply part 1, and the second end of the heat exchange part 2 is connected with the water conveying pipe 4, so that oilfield produced water and produced water are subjected to heat exchange in the heat exchange part 2, and the oilfield produced water is cooled.

For example, the first end of the heat exchange component 2 is connected to the oilfield produced water supply component 1, and may be directly connected to the oilfield produced water supply component 1, or may be connected to the oilfield produced water supply component 1 through other components, for example, in an example of the present invention, a pretreatment component may be further provided between the first end of the heat exchange component 2 and the oilfield produced water supply component 1.

The water pipe 4 is, for example, a pipe for transporting the produced water outputted from the heat exchange unit to another unit, for example, a cooling tower or a purification unit.

For example, fig. 6 is a schematic view of a connection structure of another oilfield produced water treatment apparatus according to an embodiment of the present invention, and as shown in fig. 6, the heat exchange component 2 includes a heat exchanger, and the heat exchanger includes a spiral plate heat exchanger or a plate heat exchanger.

For example, as shown in fig. 6, the treatment device for oilfield produced water according to at least one embodiment of the present invention further includes a heat sink 5, wherein the heat sink 5 is configured to dissipate heat of oilfield produced water. The heat exchange part 2 and the radiator 5 are used together, so that the load of the radiator 5 and the equipment investment can be reduced.

For example, as shown in fig. 6, the oilfield produced water treatment device further comprises a cooling tower 6, and the cooling tower 6 is arranged between the heat exchange part 2 and the purification part 3.

For example, as shown in fig. 6, the purification section 3 includes at least one of an oxidation tank 7, a biological aerated filter 8, an ultrafiltration element 9, a reverse osmosis element 10, and a resin filter 11.

For example, the heat exchange part 2 is directly connected with the oxidation tank 7, the water outlet of the pretreatment working section is connected with the hot water end inlet of the heat exchange part 2, and the water outlet pipe of the resin filter 11 is connected with the cold water end inlet of the heat exchange part 2.

For example, the resin filter 11 is made of a cationic resin material. For example, the water outlet pipe of the resin filter 11 is connected to the cold water inlet of the heat exchange unit 2, so as to perform heat exchange between the subsequent oilfield produced water and the produced water obtained by cooling and purifying the oilfield produced water, so as to lower the temperature of the subsequent oilfield produced water and raise the temperature of the produced water.

For example, as shown in fig. 6, the oxidation tank 7 includes an electrocatalytic oxidation component, or a combination of ozone and hydrogen peroxide, or an electrocatalytic oxidation component, and a combination of ozone and hydrogen peroxide. Adopt the oxidation pond to oxidize including adopting ozone and hydrogen peroxide solution to oxidize promptly, perhaps adopt the mode of electro-catalysis to oxidize, perhaps can also adopt ozone and hydrogen peroxide solution to oxidize and adopt the mode of electro-catalysis to carry out the combination of the mode of oxidizing, this oxidation mode can also include fenton oxidation, the embodiment of the utility model discloses a do not limit to this.

For example, the organic matter emulsified and dissolved in the oilfield produced water can be decomposed by using the oxidation pond, so that the pollution and blockage of macromolecular organic matter in the oilfield produced water to a subsequently adopted membrane system can be reduced, and meanwhile, the biodegradability of the oilfield produced water can be improved.

For example, in the treatment device provided in at least one embodiment of the present invention, the filler in the biological aerated filter 8 is at least one of coconut shell carbon, apricot shell carbon and coal-based activated carbon, and the filler in the conventional biological filter includes at least one of ceramsite, volcanic rock and zeolite. The embodiment of the utility model provides an in 8 specific surface area of filler of bological aerated filter be greater than the specific surface area of filler of conventional bological aerated filter, and increase the activation process on the basis of the filler that specific surface is big, can improve the biofilm formation ability and the biological adsorption ability of filler, for example, the biofilm formation cycle can be for 7 ~ 14 days.

For example, the present invention provides a treatment apparatus, further comprising a pretreatment unit, wherein the pretreatment unit comprises at least one of a conditioning tank 12, a nitrogen flotation unit 13, a hard silicon removal unit 13, a sedimentation tank 15, and a filtration unit 16.

For example, as shown in fig. 6, the filter unit 16 and the heat exchange part 2 are directly connected.

For example, in the treatment device provided in at least one embodiment of the present invention, the filtering unit 16 includes a microfiltration unit and a nanofiltration unit, the microfiltration unit may be a tubular microfiltration membrane filter, and the nanofiltration unit may be a membrane-coated fiber ball filter.

For example, the conditioning tank 12 may adjust the acidity or alkalinity of the oilfield produced water, such as by applying sodium hydroxide, sodium carbonate, or the like in a settling tank to increase the pH of the originally acidic oilfield produced water to near neutrality, and may also cause a portion of calcium ions, magnesium ions, or the like to form a precipitate to be removed. Or, sulfuric acid, hydrochloric acid, nitric acid and the like can be applied to the sedimentation tank to reduce the pH of the originally alkaline oilfield produced water to be close to neutrality, and partial calcium ions, magnesium ions, silver ions and the like can be precipitated to be removed.

For example, the backwashing water of the biological aerated filter 8 enters the regulating reservoir 12.

For example, the nitrogen gas floatation bearing device is a nitrogen gas floatation oil removal device, the nitrogen gas floatation oil removal device generates a large amount of micro-fine nitrogen bubbles as a carrier through a nitrogen gas generating device in the oilfield produced water to be treated, when oil drops and impurity floc in the oilfield produced water adhere to the bubbles, the particles with the integral density smaller than that of the water are formed, the buoyancy of the particles is larger than the gravity and the resistance to enable the particles to float up to the water surface, so that the separation process of the solid and the solid, the solid and the liquid, and the liquid in the water is completed, and simultaneously, the separated floating oil and the impurity floc are discharged out of the system through a bottom sludge discharge system and a top slag scraping system to further purify the oilfield produced water.

For example, fig. 7 is a schematic structural diagram of a nitrogen gas floatation system according to an embodiment of the present invention, as shown in fig. 7, a nitrogen gas source system (e.g., a nitrogen generator) transports nitrogen gas to a carrying device of the nitrogen gas floatation system to form the nitrogen gas floatation system, and then transports the used nitrogen gas floatation system to a degassing treatment system through a negative pressure air blower.

For example, the problem that the conventional dissolved air flotation introduces dissolved oxygen to increase the corrosion rate can be avoided by adopting nitrogen gas flotation. The top of the nitrogen gas floatation device is designed in a sealing way, a maintenance opening is reserved, a system of gas collecting and introducing pipelines is designed in a matching way, and peculiar smell gas generated by the nitrogen gas floatation is collected into a gas treatment system for treatment. Compared with air floatation, nitrogen floatation not only avoids external oxygen from being blended into oilfield produced water, but also avoids the problem that the electrochemical corrosion of oilfield produced water is aggravated, which is possibly caused by the nitrogen floatation, and can blow off dissolved gases in oilfield produced water, such as aggressive carbon dioxide, dissolved oxygen, hydrogen sulfide and the like, so that the corrosion characteristic of oilfield produced water and the operating environment of a downstream working section can be obviously improved.

The embodiment of the utility model provides a processing method of oil field produced water and processing apparatus of oil field produced water have following at least one item beneficial effect:

(1) the utility model discloses in the processing method of oil field produced water that an at least embodiment provided, carry out the heat exchange with subsequent oil field produced water and product water to make the temperature of subsequent oil field produced water reduce, and make the temperature of producing water rise, thereby can carry out the heat exchange with the clean product water after oil field produced water and the processing of high temperature, not only realized not needing the cooling of external cold source but also realized waste heat recycling.

(2) The utility model discloses in the processing method of oil field produced water that an at least embodiment provided, utilize the oxidation pond to decompose the organic matter that emulsifies, dissolves in the oil field produced water, alleviate the oil field produced water macromolecular organic matter in to the dirty stifled of the membrane system of follow-up adoption, improve the biodegradability of oil field produced water simultaneously.

(3) The utility model discloses in the processing method of oil field produced water that an at least embodiment provided, the bological aerated filter replaces traditional biochemical pond, collects biological oxidation, biological flocculation and filters in an organic whole, need not set up two heavy ponds, has both satisfied biochemical requirement, has reached the purpose that reduces area and capital construction investment again. The biological aerated filter has the advantages of high oxygen transmission efficiency, small aeration amount, low oxygen supply power consumption, low power consumption for treating unit oilfield produced water, high automation degree, convenient operation and management and short biofilm formation period of 14-21 days.

The following points need to be explained:

(1) the embodiment of the present invention is only related to the structure related to the embodiment of the present invention, and other structures can refer to the common design.

(2) In the drawings, which are used to describe embodiments of the invention for purposes of clarity, the thickness of layers or regions are exaggerated or reduced, i.e., the drawings are not drawn to scale. It will be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" or "under" another element, it can be "directly on" or "under" the other element or intervening elements may be present.

(3) Without conflict, embodiments of the present invention and features of the embodiments may be combined with each other to arrive at new embodiments.

The above description is only the specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto, and the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims (9)

1. An oil field produced water treatment device, comprising:

an oilfield produced water providing component configured to provide oilfield produced water;

the heat exchange component is configured to carry out cooling treatment on the oilfield produced water;

the purification component is configured to purify the oilfield produced water subjected to cooling treatment to obtain produced water;

a water transport pipe configured to transport the produced water,

the first end of the heat exchange part is connected with an oilfield produced water supply part, and the second end of the heat exchange part is connected with the water delivery pipe, so that oilfield produced water and the produced water are subjected to heat exchange in the heat exchange part, and the oilfield produced water is cooled.

2. The process apparatus of claim 1, wherein the heat exchange component comprises a heat exchanger.

3. The treatment apparatus of claim 2, further comprising a heat sink, wherein the heat sink is configured to dissipate heat from the oilfield produced water.

4. The process arrangement of any one of claims 1 to 3, further comprising a cooling tower, wherein the cooling tower is disposed between the heat exchange component and the purification component.

5. The treatment apparatus of claim 4, wherein the purification component comprises at least one of an oxidation tank, a biological aerated filter, an ultrafiltration element, a reverse osmosis element, and a resin filter.

6. The treatment apparatus of claim 5, wherein the oxidation cell comprises an electrocatalytic oxidation component, or a combination of ozone and hydrogen peroxide, or a combination of an electrocatalytic oxidation component and ozone and hydrogen peroxide.

7. The treatment apparatus according to claim 5, wherein the filler in the biological aerated filter is at least one of coconut shell carbon, apricot shell carbon and coal-based activated carbon.

8. The treatment apparatus of claim 1, further comprising a pretreatment unit, wherein the pretreatment unit comprises at least one of a conditioning tank, a nitrogen flotation unit, a de-hardbanding unit, a settling tank, and a filtration unit.

9. The treatment device of claim 8, wherein the filtration unit comprises a membrane-coated fiber ball filter and a tubular microfiltration membrane filter.

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