CN114940557A - Fracturing flow-back fluid pretreatment system and method for efficiently breaking gel and oxidizing to remove organic matters - Google Patents
Fracturing flow-back fluid pretreatment system and method for efficiently breaking gel and oxidizing to remove organic matters Download PDFInfo
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F9/00—Multistage treatment of water, waste water or sewage
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/02—Treatment of water, waste water, or sewage by heating
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/24—Treatment of water, waste water, or sewage by flotation
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
- C02F1/5236—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using inorganic agents
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
- C02F1/54—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using organic material
- C02F1/56—Macromolecular compounds
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/72—Treatment of water, waste water, or sewage by oxidation
- C02F1/722—Oxidation by peroxides
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/30—Organic compounds
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
- C02F2103/10—Nature of the water, waste water, sewage or sludge to be treated from quarries or from mining activities
Abstract
The invention discloses a fracturing flow-back fluid pretreatment system and a method for efficiently breaking gel and oxidizing to remove organic matters, wherein the system comprises a fracturing flow-back fluid raw water storage tank, a heating device, a feeding pump, a reactor and an air floatation device; the method comprises the following steps: (1) heating the fracturing flow-back fluid; (2) after heating, the fracturing flow-back fluid is subjected to gel breaking oxidation reaction with a gel breaker and an oxidant in a reactor to remove organic matters; (3) and removing inorganic colloid and partial organic matters from the produced water after gel breaking and oxidation by using an air flotation device. According to the invention, the preheating plate type heat exchanger and the heating plate type heat exchanger are adopted, after heat exchange and temperature rise are carried out on the fracturing flow-back fluid, the gel breaker and hydrogen peroxide are simultaneously added for gel breaking oxidation reaction, so that the reaction activity of the gel breaker is favorably improved, and the rapid and efficient gel breaking reaction is realized; the gel breaker and the hydrogen peroxide both belong to strong oxidizing agents, and can achieve the effects of mutual excitation and synergistic gel breaking and organic matter removal.
Description
The technical field is as follows:
the invention relates to the technical field of sewage treatment, in particular to a fracturing flow-back fluid pretreatment system and method for efficiently breaking gel and oxidizing to remove organic matters.
The background art comprises the following steps:
the fracturing flow-back fluid mainly refers to residual fracturing fluid which is discharged from an oil-gas well after fracturing construction, is usually colorless or faint yellow, has a certain pungent smell, mainly comprises fracturing virgin cement and gel breaking flow-back fluid, and contains guar gum, formaldehyde, petroleum and other various additives. The fracturing flowback fluid has the characteristics of high salt (mainly sodium chloride), high COD (chemical oxygen demand), high viscosity and difficult degradation, and can cause soil hardening, salinization, surface water and underground water pollution and destroy the ecological environment by direct discharge.
The common treatment methods for the fracturing flowback fluid comprise the following steps:
(1) a reinjection method: collecting the fracturing flowback fluid, performing pretreatment such as gel breaking, flocculation, oxidation and the like in a centralized manner to reach the water injection standard of the oil-gas field, and directly injecting the fracturing flowback fluid into a reservoir for oil extraction or gas production. The reinjection layer is preferably a depleted layer or a waste layer, has enough storage space, has no water leakage from the upper isolation layer and the lower isolation layer, has good transverse connectivity and cannot pollute underground water. The suspension solid concentration, the median diameter and the oil content of the reinjection fracturing flow-back fluid and the pH value of the reinjection fluid meet the reinjection requirements.
(2) Discharging after reaching the standard. The standard discharge is that after the fracturing flowback fluid is treated, all water quality indexes reach the national or local discharge standard and are directly discharged into the early natural environment. The water quality discharge standard generally complies with the integrated wastewater discharge standard (GB8978-1996) or the surface water quality standard (GB 3838-2002). The common field process comprises gel breaking → flocculation → cloth bag filtration → quartz sand filtration → activated carbon filtration → precise filter → ultrafiltration → reverse osmosis → salt separation and the like.
(3) The reuse method comprises the following steps: after simple treatment is carried out on the fracturing flow-back fluid, the produced water is repeatedly used for the configuration of new fracturing flow-back fluid after reaching the water quality index of the compound fracturing fluid; there are two main ways: the fracturing flow-back fluid is treated into clear water for preparing new fracturing flow-back fluid, the mode is similar to the treatment of standard discharge, COD and salt need to be removed, the viscosity of the base fluid of the fracturing fluid is reduced due to the existence of the salt, and the crosslinking time is prolonged. Secondly, the useful components in the flowback fluid are reserved, the harmful components are removed, and the requirement of the fracturing fluid preparation is met by supplementing part of auxiliary agents. The related researches comprise the treatment processes of gel breaking → coagulation → liquid preparation and oxidation viscosity reduction → flocculation sedimentation → solid-liquid separation → multi-stage filtration and the like.
Therefore, no matter the fracturing fluid is reinjected, recycled or discharged after reaching the standard, organic viscous substances such as vegetable gum and the like in the fracturing fluid need to be further treated after inorganic impurities and colloid are removed, so that the water quality requirement of reinjection, recycling or discharging after reaching the standard is met. Therefore, gel breaking, organic matter removal, coagulating sedimentation, inorganic impurity removal and colloid become key steps and technologies for treating the fracturing flowback fluid.
At present, the process steps of gel breaking, organic matter removal, coagulating sedimentation and the like all react at normal temperature, the temperature is 5-30 ℃, but common gel breakers are high-temperature gel breakers, the reaction efficiency is low at normal temperature, and gel breaking is incomplete. The oxidation viscosity reduction process adopts normal high-grade oxidation or high-temperature wet oxidation at normal temperature and normal pressure. The common advanced oxidation reaction has low efficiency, the gel breaking and COD removal rate is not ideal, and the organic matter removal rate is generally less than 30 percent. The high-temperature wet oxidation has high oxidation efficiency and thorough removal of organic matters, but the reaction conditions are harsh, the temperature needs to reach 120-320 ℃, the pressure is between 5 and 20Mpa, the requirement on equipment is extremely high, and the operation cost is very high.
The invention content is as follows:
the invention aims to provide a fracturing flow-back fluid pretreatment system which is simple in structure, low in equipment investment cost and capable of efficiently breaking gel and oxidizing to remove organic matters.
The second purpose of the invention is to provide a fracturing flow-back fluid pretreatment method which has low energy consumption and high efficiency and is used for removing organic matters through gel breaking and oxidation.
The first object of the invention is implemented by the following technical solution: a fracturing flow-back fluid pretreatment system for efficiently breaking gel and oxidizing to remove organic matters comprises a fracturing flow-back fluid raw water storage tank, a heating device, a feeding pump, a reactor and an air floatation device, wherein an outlet of the fracturing flow-back fluid raw water storage tank is connected with a liquid inlet of the heating device through a pipeline, a liquid outlet of the heating device is connected with a liquid inlet of the feeding pump through a pipeline, a liquid outlet of the feeding pump is connected with a liquid inlet of the reactor through a pipeline, a liquid outlet of the reactor is connected with a liquid inlet of the air floatation device through a pipeline, and a water outlet of the air floatation device is connected with an inlet end of an air floatation water production pipeline; a pipeline connecting the liquid outlet of the heating device and the liquid inlet of the reactor, or the reactor is provided with a gel breaker dosing port and an oxidant dosing port; the air floatation device is provided with a coagulant dosing port and a flocculant dosing port.
Further, the heating device comprises a preheating heat exchanger and a heating heat exchanger, an outlet of the fracturing flow-back liquid raw water storage tank is connected with a liquid inlet of the preheating heat exchanger through a pipeline, a liquid outlet of the preheating heat exchanger is respectively connected with a water return port of the fracturing flow-back liquid raw water storage tank and a liquid inlet of the heating heat exchanger through pipelines, and a liquid outlet of the heating heat exchanger is connected with a liquid inlet of the reactor through a pipeline; the water outlet of the pressurized dissolved air floatation device is connected with the water inlet of the preheating heat exchanger through a pipeline, and the water outlet of the preheating heat exchanger is connected with the inlet end of the air floatation water production pipeline; the outlet end of the steam pipeline is connected with the air inlet of the heating heat exchanger through a pipeline, and the condensate outlet of the heating heat exchanger is connected with the inlet end of the condensate pipeline.
Further, the air floatation device is a pressurized dissolved air floatation device.
Furthermore, the fracturing flow-back fluid pretreatment system capable of efficiently breaking gel and oxidizing to remove organic matters further comprises a gel breaker dosing device, an oxidant dosing device, a coagulant dosing device and a flocculant dosing device; the outlet of the gel breaker dosing device is connected with the gel breaker dosing port through a pipeline; the outlet of the oxidant dosing device is connected with the oxidant dosing port through a pipeline; the outlet of the coagulant dosing device is connected with the coagulant dosing port through a pipeline; the outlet of the flocculant dosing device is connected with the flocculant dosing port through a pipeline.
The second purpose of the invention is implemented by the following technical scheme: a fracturing flow-back fluid pretreatment method for efficiently breaking gel and oxidizing to remove organic matters comprises the following steps: (1) heating the fracturing flow-back fluid; (2) after heating, the fracturing flow-back fluid is subjected to gel breaking oxidation reaction with a gel breaker and an oxidant in a reactor to remove organic matters; (3) removing inorganic colloid and partial organic matters from the produced water after gel breaking and oxidation by an air floatation device; wherein the content of the first and second substances,
(1) heating and fracturing flow-back fluid: sending the fracturing flow-back fluid into a heating device for heating, heating the fracturing flow-back fluid to be not lower than 52 ℃, and sending the fracturing flow-back fluid into a reactor;
(2) and (3) after heating, performing gel breaking oxidation reaction on the fracturing flow-back fluid, a gel breaker and an oxidant in a reactor to remove organic matters: conveying the fracturing flow-back fluid heated in the step (1) to a reactor through a feed pump, wherein the outlet pressure of the feed pump is not lower than 5 bar; adding an oxidant and a gel breaker into the fracturing flow-back fluid; the operating pressure of the reactor is between 4 and 5 bar; the reaction temperature is controlled at 50-60 ℃; the residence time of the fracturing flow-back fluid in the reactor is not less than 0.5h, the fracturing flow-back fluid, a gel breaker and an oxidant are subjected to gel breaking oxidation reaction to remove organic matters, and produced water after gel breaking oxidation enters an air floatation device after pressure relief; the macromolecular glue organic matters in the water react with the gel breaker and the oxidant, open loop and chain breakage and partial carbonization are removed, the viscosity of the fracturing flowback fluid is greatly reduced, and the removal rate of the organic matters reaches 40-60%.
(3) Removing inorganic colloid and partial organic matters from the produced water after gel breaking and oxidation by an air floatation device: the water produced after gel breaking and oxidation enters an air flotation device after pressure relief, a coagulant and a flocculant are added into the air flotation device, inorganic colloid and partial organic matters can efficiently react with the coagulant and the flocculant to generate large-particle flocs, the large-particle flocs are removed through air flotation, and the air flotation water is removed to a subsequent treatment section. The viscosity of the fracturing flowback fluid after gel breaking and oxidation is greatly reduced, inorganic colloid and partial organic matters can efficiently react with a coagulant and a flocculant to generate large-particle flocs, and the large-particle flocs are removed by air flotation, wherein suspended matters in water produced by air flotation are less than 20mg/L, petroleum is less than 10mg/L, and the chroma is less than 200 times.
Further, the heating method in the step (1) is specifically as follows: the fracturing flow-back fluid firstly enters a preheating heat exchanger to exchange heat with air floatation produced water of a rear-end air floatation device so as to recover heat of the air floatation produced water, the temperature of the inlet water of the fracturing flow-back fluid is 5-25 ℃, the temperature of the air floatation produced water is 45-55 ℃, the water inlet amount of the fracturing flow-back fluid in the preheating heat exchanger is not less than 2 times of the water inlet amount of the air floatation produced water, sufficient heat exchange is carried out to reduce the final outlet water temperature of the air floatation produced water, part or all of the fracturing flow-back fluid after heat exchange enters a heating heat exchanger to exchange heat with steam, the temperature is further heated to be not less than 52 ℃, if the system processing capacity is limited, only part of the fracturing flow-back fluid after heat exchange enters the heating heat exchanger, and the rest of the fracturing flow-back fluid after heating returns to a fracturing flow-back fluid raw water storage tank; the air floatation water production temperature after heat exchange is less than 30 ℃, and the water inlet requirement of the subsequent working section is met.
Further, the gel breaker is persulfate, and the adding amount of the gel breaker is 0.1-0.3 g/L.
Further, the oxidant is hydrogen peroxide, the mass percentage concentration of the hydrogen peroxide is not lower than 10%, and the adding amount of the oxidant is 0.2-1 g/L.
Further, the coagulant is aluminum salt or iron salt, and the adding amount of the coagulant is 300-1000mg/L
Further, PAM is adopted as the flocculating agent, and the adding amount of the flocculating agent is 3-10 mg/L.
The invention has the advantages that:
(1) the process adopts a preheating plate type heat exchanger and a heating plate type heat exchanger, and after heat exchange and temperature rise are carried out on the fracturing flow-back fluid, the gel breaker and hydrogen peroxide are simultaneously added for gel breaking oxidation reaction, so that the reaction activity of the gel breaker is favorably improved, and the rapid and efficient gel breaking reaction is realized;
(2) simultaneously adding a gel breaker and hydrogen peroxide for gel breaking oxidation reaction, wherein the gel breaker and the hydrogen peroxide both belong to strong oxidizing agents, so that mutual excitation and synergistic action can be achieved, and the effects of gel breaking and organic matter removal are improved;
(3) the temperature and pressure conditions required by the gel breaking oxidation reaction are mild, the requirement on equipment is low, and the operation cost is reduced;
(4) after the gel breaking oxidation reaction, the effluent temperature is higher, compared with the conventional water temperature, the coagulation reaction efficiency is high, the adding amount of a coagulant can be reduced, the raw material cost is saved, and a better treatment effect is achieved;
(5) the air floatation produced water exchanges heat with new fracturing flow-back liquid raw water through the preheating plate type heat exchanger, the outlet water temperature can be reduced, the water temperature is ensured to meet the water inlet requirement of the subsequent section, meanwhile, the heat is recycled, and the total energy consumption of the system is saved.
Description of the drawings:
in order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a schematic view of a fracturing flow-back fluid pretreatment system for efficiently breaking gel and oxidizing to remove organic substances in embodiment 1.
The fracturing flow-back liquid raw water system comprises a fracturing flow-back liquid raw water storage tank 1, a heating device 2, a preheating heat exchanger 2.1, a heating heat exchanger 2.2, a feeding pump 3, a reactor 4, an air flotation device 5, a gel breaker dosing device 6, an oxidant dosing device 7, a coagulant dosing device 8, a flocculant dosing device 9, an air flotation water production pipeline 10, a steam pipeline 11 and a condensed water pipeline 12.
The specific implementation mode is as follows:
the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without inventive step based on the embodiments of the present invention, are within the scope of protection of the present invention.
Example 1: as shown in fig. 1, a fracturing flow-back fluid pretreatment system for efficiently breaking gel and oxidizing to remove organic matters comprises a fracturing flow-back fluid raw water storage tank 1, a heating device 2, a feed pump 3, a reactor 4, an air flotation device 5, a gel breaker dosing device 6, an oxidant dosing device 7, a coagulant dosing device 8 and a flocculant dosing device 9.
The reactor 4 of this embodiment is a stainless steel closed pressure vessel, the pressure-bearing capacity is not lower than 10bar, the reactor 4 body is provided with a pressure gauge, and the outlet pipeline is provided with a flow-regulating pressure-regulating valve to maintain the operating pressure of the reactor 4 between 4-5 bar.
The air flotation device 5 used in this embodiment is a pressurized dissolved air flotation device, which is manufactured by sn-free industrial environment technologies, inc, and has a model number of GF 10T. The air flotation device 5 adopts a water production part reflux pressure dissolved air flotation technology, a coagulant reaction area and a flocculant reaction area are arranged at the front section of the air flotation, and an inorganic coagulant and a macromolecular organic flocculant are respectively added through a coagulant dosing device 8 and a flocculant dosing device 9.
The heating device 2 of the embodiment comprises a preheating heat exchanger 2.1 and a heating heat exchanger 2.2, and the preheating heat exchanger 2.1 and the heating heat exchanger 2.2 of the embodiment are plate heat exchangers.
An outlet of the fracturing flow-back liquid raw water storage tank 1 is connected with a liquid inlet of a preheating heat exchanger 2.1 through a pipeline, a liquid outlet of the preheating heat exchanger 2.1 is respectively connected with a water return port of the fracturing flow-back liquid raw water storage tank 1 and a liquid inlet of a heating heat exchanger 2.2 through pipelines, a liquid outlet of the heating heat exchanger 2.2 is connected with a liquid inlet of a feeding pump 3 through a pipeline, and a liquid outlet of the feeding pump 3 is connected with a liquid inlet of a reactor 4 through a pipeline; a liquid outlet of the reactor 4 is connected with a liquid inlet of the air floatation device 5 through a pipeline, and a water outlet of the air floatation device 5 is connected with a water inlet of the preheating heat exchanger 2.1 through a pipeline; the water outlet of the preheating heat exchanger 2.1 is connected with the inlet end of an air floatation water production pipeline 10; the outlet end of the steam pipeline 11 is connected with the air inlet of the heating heat exchanger 2.2 through a pipeline, and the condensate outlet of the heating heat exchanger 2.2 is connected with the inlet end of the condensate pipeline 12. A gel breaker dosing port and an oxidant dosing port are arranged on a pipeline connecting a liquid outlet of the feeding pump 3 and a liquid inlet of the reactor 4; the outlet of the gel breaker dosing device 6 is connected with the gel breaker dosing port through a pipeline; the outlet of the oxidant dosing device 7 is connected with the oxidant dosing port through a pipeline; the air flotation device 5 is provided with a coagulant dosing port and a flocculant dosing port, and the outlet of the coagulant dosing device 8 is connected with the coagulant dosing port through a pipeline; the outlet of the flocculant dosing device 9 is connected with the flocculant dosing port through a pipeline. In this embodiment, the structure of the gel breaker dosing device 6, the structure of the oxidant dosing device 7, the structure of the coagulant dosing device 8, and the structure of the flocculant dosing device 9 are the same, and each of the gel breaker dosing device, the oxidant dosing device, the coagulant dosing device 8, and the flocculant dosing device 9 includes a dosing tank and a dosing pump, and an outlet of the dosing tank is connected with an inlet of the dosing pump through a pipeline.
Example 2: the method for pretreating fracturing flow-back fluid by using the system for pretreating fracturing flow-back fluid of embodiment 1 comprises the following steps: (1) heating the fracturing flow-back fluid; (2) after heating, the fracturing flow-back fluid is subjected to gel breaking oxidation reaction with a gel breaker and an oxidant in a reactor to remove organic matters; (3) removing inorganic colloid and partial organic matters from the produced water after gel breaking and oxidation by an air floatation device; wherein the content of the first and second substances,
(1) heating and fracturing flow-back fluid: sending the fracturing flow-back fluid into a heating device 2 for heating, heating the fracturing flow-back fluid to be not lower than 52 ℃, and sending the fracturing flow-back fluid into a reactor; in the embodiment, the fracturing flow-back fluid firstly enters a preheating heat exchanger 2.1 and exchanges heat with air floatation water production of a rear-end air floatation device 5 to recover heat of the air floatation water production, and the inlet temperature of the fracturing flow-back fluid is 5-25 ℃, and the temperature is 8 ℃ in the embodiment; the air floatation water production temperature is 45-55 ℃, and the temperature is 46 ℃ in the embodiment; the water inflow of the fracturing flow-back fluid in the preheating heat exchanger 2.1 is not less than 2 times of the water inflow of the air flotation water production, the water inflow of the fracturing flow-back fluid in the preheating heat exchanger 2.1 is 20t/h, and the water inflow of the air flotation water production is 10 t/h; the temperature of the fracturing flow-back fluid after heat exchange is 16.5 ℃, the fracturing flow-back fluid enters a heating heat exchanger 2.2 at the water inflow of 10t/h, and exchanges heat with steam, the steam in the embodiment adopts 0.5Mpa low-pressure saturated steam, the steam temperature is 150 ℃, the temperature is further heated to be not lower than 52 ℃, and the embodiment is heated to 52 ℃; returning the rest heated fracturing flow-back fluid to the fracturing flow-back fluid raw water storage tank 1; the temperature of air floatation water production after heat exchange is less than 30 ℃, the temperature is 29 ℃ in the embodiment, and the water inlet requirement of the subsequent working section is met.
(2) And (3) after heating, the fracturing flow-back fluid is subjected to gel breaking oxidation reaction with a gel breaker and an oxidant in the reactor 4 to remove organic matters: the fracturing flow-back fluid heated in the step (1), the quality of the inflow water of the fracturing flow-back fluid in the embodiment is shown in table 1, the inflow water is conveyed to a reactor 4 through a feed pump 3, and the outlet pressure of the feed pump 3 is not lower than 5 bar; adding an oxidant and a gel breaker into the fracturing flow-back fluid; in the embodiment, the gel breaker is ammonium persulfate, and the dosage of the gel breaker is 200 mg/L. The oxidant in this embodiment is hydrogen peroxide, the mass percentage concentration of the hydrogen peroxide is not less than 10%, the mass percentage concentration of the hydrogen peroxide in this embodiment is 10%, and the addition amount of the oxidant is 700 mg/L.
The operating pressure of the reactor 4 is between 4 and 5 bar; the reaction temperature is controlled at 50-60 ℃; the residence time of the fracturing flow-back fluid in the reactor 4 is not less than 0.5h, and the residence time in the embodiment is 40 min; the fracturing flow-back fluid, the gel breaker and the oxidant are subjected to gel breaking oxidation reaction to remove organic matters, and the produced water after gel breaking oxidation enters the air floatation device 5 after pressure relief; macromolecular glue organic matters in water react with the gel breaker and the oxidant, open loop and chain breakage are carried out, partial carbonization is carried out, the viscosity of the fracturing flowback fluid is greatly reduced, and the removal rate of the organic matters reaches 40-60%. The quality of the water produced by the reactor 4 of this example is shown in Table 1;
(3) removing inorganic colloid and partial organic matters from the produced water after gel breaking and oxidation by an air floatation device: the water produced after gel breaking oxidation enters an air flotation device 5 after pressure relief, the water quality of the water inlet of the air flotation device 5 in the embodiment is shown in a table 2, the air flotation device 5 adopts a water production part reflux pressure dissolved air flotation technology, the reflux amount is 20%, a coagulant reaction area and a flocculant reaction area are arranged at the front section of air flotation, and a coagulant and a flocculant are respectively added through a coagulant adding device 8 and a flocculant adding device 9; in the embodiment, the coagulant is polyaluminium chloride, and the adding amount of the coagulant is 400 mg/L; PAM was used as the flocculant in this example, and the amount of flocculant added was 5 mg/L. Inorganic colloid and partial organic matter can react with coagulant and flocculant to produce large granular floc, which is eliminated through floatation and the water produced through floatation is treated in subsequent treatment. The viscosity of the fracturing flowback fluid after gel breaking and oxidation is greatly reduced, inorganic colloid and partial organic matters can efficiently react with a coagulant and a flocculant to generate large-particle flocs, and the large-particle flocs are removed by air flotation, wherein suspended matters in water produced by air flotation are less than 20mg/L, petroleum is less than 10mg/L, and the chroma is less than 200 times. The quality of the water produced by the air flotation device 5 in the embodiment is shown in the table 2.
Comparative example 1: a method for pretreating a frac flowback fluid, which is different from example 2 in that the frac flowback fluid is not heated. The quality and the inflow quantity of the inflow water of the fracturing flow-back fluid are the same as those of the inflow water of the embodiment 1 and are shown in the table 1, the inflow water is conveyed to a reactor 4 through a feeding pump 3, and the outlet pressure of the feeding pump 3 is not lower than 5 bar; adding an oxidant and a gel breaker into the fracturing flow-back fluid; in the embodiment, the gel breaker is ammonium persulfate, and the dosage of the gel breaker is 200 mg/L. The oxidant in this embodiment is hydrogen peroxide, the mass percentage concentration of the hydrogen peroxide is not less than 10%, the mass percentage concentration of the hydrogen peroxide in this embodiment is 10%, and the addition amount of the oxidant is 700 mg/L.
The operating pressure of the reactor 4 is between 4 and 5 bar; reacting at normal temperature; the residence time of the fracturing flow-back fluid in the reactor 4 is 40 min; the fracturing flow-back fluid, the gel breaker and the oxidant are subjected to gel breaking oxidation reaction to remove organic matters, and the produced water after gel breaking oxidation enters the air floatation device 5 after pressure relief; the quality of the water produced by the reactor 4 is shown in the table 1;
the produced water after gel breaking and oxidation enters an air flotation device 5 after pressure relief, the water quality of the inlet water of the air flotation device 5 is shown in the table 2, and a coagulant and a flocculant are added into the air flotation device 5, wherein in the embodiment, the coagulant is polyaluminium chloride, and the adding amount of the coagulant is 400 mg/L; PAM was used as the flocculant in this example, and the amount of flocculant added was 5 mg/L. Inorganic colloid and partial organic matter can react with coagulant and flocculant to produce large granular floc, which is eliminated through floatation and the water produced through floatation is treated in subsequent treatment. The quality of the water produced by the air flotation device 5 is shown in the table 2.
Comparative example 2: the pretreatment method of the fracturing flow-back fluid is different from the pretreatment method of the comparative example 1 in that an oxidant, namely hydrogen peroxide, is not added, and other steps and parameters are the same as those of the comparative example 1.
Comparative example 3: the method for pretreating the fracturing flow-back fluid is different from the method in the embodiment 2 in that an oxidant, namely hydrogen peroxide, is not added, and other steps and parameters are the same as those in the embodiment 2.
Table 1: comparison table of quality of reactor feed water and quality of produced water in example 2 and comparative examples 1 to 3
Table 2: comparison table of inlet water quality and produced water quality of air flotation device in example 2 and comparative examples 1-3
Compared with the comparative examples 1-3, the produced water quality after the fracturing flow-back fluid is pretreated by the method in the embodiment 2 is better removed from the viscosity, chromaticity, organic matters, petroleum, inorganic colloids, particles and the like of the fracturing flow-back fluid treated by the method in the embodiment 2, the treatment effect is greatly improved, a foundation is laid for a subsequent advanced treatment process, the stable and efficient operation of a subsequent system is ensured, and the efficient treatment of the fracturing flow-back fluid is realized.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and should not be taken as limiting the scope of the present invention, which is intended to cover any modifications, equivalents, improvements, etc. within the spirit and scope of the present invention.
Claims (10)
1. A fracturing flow-back fluid pretreatment system for efficiently breaking gel and oxidizing to remove organic matters is characterized by comprising a fracturing flow-back fluid raw water storage tank, a heating device, a feeding pump, a reactor and an air floatation device, wherein an outlet of the fracturing flow-back fluid raw water storage tank is connected with a liquid inlet of the heating device through a pipeline, a liquid outlet of the heating device is connected with a liquid inlet of the feeding pump through a pipeline, a liquid outlet of the feeding pump is connected with a liquid inlet of the reactor through a pipeline, a liquid outlet of the reactor is connected with a liquid inlet of the air floatation device through a pipeline, and a water outlet of the air floatation device is connected with an inlet end of an air floatation water production pipeline; a pipeline connecting the liquid outlet of the heating device and the liquid inlet of the reactor, or the reactor is provided with a gel breaker dosing port and an oxidant dosing port; the air floatation device is provided with a coagulant dosing port and a flocculant dosing port.
2. The system for pretreating fracturing flow-back fluid for efficiently breaking gel and oxidizing to remove organic matters according to claim 1, wherein the heating device comprises a preheating heat exchanger and a heating heat exchanger, an outlet of the fracturing flow-back fluid raw water storage tank is connected with a liquid inlet of the preheating heat exchanger through a pipeline, a liquid outlet of the preheating heat exchanger is respectively connected with a water return port of the fracturing flow-back fluid raw water storage tank and a liquid inlet of the heating heat exchanger through pipelines, and a liquid outlet of the heating heat exchanger is connected with a liquid inlet of the reactor through a pipeline; the water outlet of the pressurized dissolved air floatation device is connected with the water inlet of the preheating heat exchanger through a pipeline, and the water outlet of the preheating heat exchanger is connected with the inlet end of the air floatation water production pipeline; the outlet end of the steam pipeline is connected with the air inlet of the heating heat exchanger through a pipeline, and the condensate outlet of the heating heat exchanger is connected with the inlet end of the condensate pipeline.
3. The system for pretreating fracturing flow-back fluid by efficiently breaking gel and oxidizing to remove organic matters according to claim 1, wherein the air flotation device is a pressurized dissolved air flotation device.
4. The fracturing flow-back fluid pretreatment system for efficiently breaking gel and oxidizing to remove organic matters according to any one of claims 1 to 3, further comprising a gel breaker dosing device, an oxidant dosing device, a coagulant dosing device and a flocculant dosing device; the outlet of the gel breaker dosing device is connected with the gel breaker dosing port through a pipeline; the outlet of the oxidant dosing device is connected with the oxidant dosing port through a pipeline; the outlet of the coagulant dosing device is connected with the coagulant dosing port through a pipeline; the outlet of the flocculant dosing device is connected with the flocculant dosing port through a pipeline.
5. The method for pretreating the fracturing flow-back fluid by using the system for pretreating the fracturing flow-back fluid by efficiently breaking the gel and oxidizing the organic substances as claimed in any one of claims 1 to 4, comprises the following steps of: (1) heating the fracturing flow-back fluid; (2) after heating, the fracturing flow-back fluid is subjected to gel breaking oxidation reaction with a gel breaker and an oxidant in a reactor to remove organic matters; (3) removing inorganic colloid and partial organic matters from the produced water after gel breaking and oxidation by an air floatation device; wherein the content of the first and second substances,
(1) heating and fracturing flow-back fluid: sending the fracturing flow-back fluid into a heating device for heating, heating the fracturing flow-back fluid to be not lower than 52 ℃, and sending the fracturing flow-back fluid into a reactor;
(2) and (3) after heating, performing gel breaking oxidation reaction on the fracturing flow-back fluid, a gel breaker and an oxidant in a reactor to remove organic matters: conveying the fracturing flow-back fluid heated in the step (1) to a reactor through a feed pump, wherein the outlet pressure of the feed pump is not lower than 5 bar; adding an oxidant and a gel breaker into the fracturing flow-back fluid; the operating pressure of the reactor is between 4 and 5 bar; the reaction temperature is controlled at 50-60 ℃; the residence time of the fracturing flow-back fluid in the reactor is not less than 0.5h, the fracturing flow-back fluid, a gel breaker and an oxidant are subjected to gel breaking oxidation reaction to remove organic matters, and produced water after gel breaking oxidation enters an air floatation device after pressure relief;
(3) removing inorganic colloid and partial organic matters from the produced water after gel breaking and oxidation by an air floatation device: the water produced after gel breaking and oxidation enters an air flotation device after pressure relief, a coagulant and a flocculant are added into the air flotation device, inorganic colloid and partial organic matters can efficiently react with the coagulant and the flocculant to generate large-particle flocs, the large-particle flocs are removed through air flotation, and the air flotation water is removed to a subsequent treatment section.
6. The fracturing flow-back fluid pretreatment method of claim 5, wherein the heating method of step (1) is specifically: the fracturing flow-back fluid firstly enters a preheating heat exchanger to exchange heat with air floatation produced water of a rear-end air floatation device so as to recover heat of the air floatation produced water, the inlet water temperature of the fracturing flow-back fluid is 5-25 ℃, the air floatation produced water temperature is 45-55 ℃, the inlet water quantity of the fracturing flow-back fluid in the preheating heat exchanger is not less than 2 times of the inlet water quantity of the air floatation produced water, part or all of the fracturing flow-back fluid after heat exchange enters a heating heat exchanger to exchange heat with steam, and the temperature is further heated to be not less than 52 ℃; the temperature of air floatation water production after heat exchange is less than 30 ℃, and the water inlet requirement of the subsequent working section is met.
7. The method for pretreating fracturing flow-back fluid according to claim 5, wherein the gel breaker is persulfate, and the dosage of the gel breaker is 0.1-0.3 g/L.
8. The method for pretreating fracturing flow-back fluid according to claim 5, wherein the oxidant is hydrogen peroxide, the mass percentage concentration of the hydrogen peroxide is not less than 10%, and the addition amount of the oxidant is 0.2-1 g/L.
9. The pretreatment method for the fracturing flow-back fluid according to claim 5, wherein the coagulant is aluminum salt or iron salt, and the addition amount of the coagulant is 300-1000 mg/L.
10. The method for pretreating fracturing flow-back fluid according to claim 5, wherein PAM is adopted as the flocculant, and the addition amount of the flocculant is 3-10 mg/L.
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20120168364A1 (en) * | 2009-06-04 | 2012-07-05 | Evans Thomas S | Oil field water recycling system and method |
| US20130118994A1 (en) * | 2011-03-21 | 2013-05-16 | R360 Environmental Solutions | System and Methods for Wastewater and Produced Water Cleaning and Reclamation |
| CN107235532A (en) * | 2017-05-16 | 2017-10-10 | 方明环保科技(漳州)有限公司 | The separator of energy oil-water separation |
| CN207158951U (en) * | 2017-06-13 | 2018-03-30 | 陕西省石油化工研究设计院 | A kind of vehicle-mounted removable processing equipment for recycling of fracturing outlet liquid |
| CN207276369U (en) * | 2016-12-29 | 2018-04-27 | 黑龙江吉纳森生物工程股份有限公司 | Processing unit is arranged outside a kind of fracturing outlet liquid |
| CN108585279A (en) * | 2018-05-16 | 2018-09-28 | 中国石油天然气集团有限公司 | A kind of processing method of guanidine glue fracturing outlet liquid |
-
2022
- 2022-06-24 CN CN202210723110.5A patent/CN114940557A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20120168364A1 (en) * | 2009-06-04 | 2012-07-05 | Evans Thomas S | Oil field water recycling system and method |
| US20130118994A1 (en) * | 2011-03-21 | 2013-05-16 | R360 Environmental Solutions | System and Methods for Wastewater and Produced Water Cleaning and Reclamation |
| CN207276369U (en) * | 2016-12-29 | 2018-04-27 | 黑龙江吉纳森生物工程股份有限公司 | Processing unit is arranged outside a kind of fracturing outlet liquid |
| CN107235532A (en) * | 2017-05-16 | 2017-10-10 | 方明环保科技(漳州)有限公司 | The separator of energy oil-water separation |
| CN207158951U (en) * | 2017-06-13 | 2018-03-30 | 陕西省石油化工研究设计院 | A kind of vehicle-mounted removable processing equipment for recycling of fracturing outlet liquid |
| CN108585279A (en) * | 2018-05-16 | 2018-09-28 | 中国石油天然气集团有限公司 | A kind of processing method of guanidine glue fracturing outlet liquid |
Non-Patent Citations (1)
| Title |
|---|
| 王继刚等: "《油井选择性化学堵水技术》", 黑龙江科学技术出版社, pages: 129 - 131 * |
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