Defoaming device for pretreatment section of shale gas produced water

Abstract

The invention relates to the technical field of shale gas produced water pretreatment, and discloses a shale gas produced water pretreatment section defoaming device which comprises a first detection chamber, a dosing chamber and a PLC control box, the first detection chamber comprises a water inlet used for providing raw water and a branch water outlet communicated with the dosing chamber; an optical sensor for detecting the content of foam in raw water is arranged in the first detection chamber, is connected with the PLC control box through a signal line and transmits detection data to the PLC control box; a defoaming agent inlet is formed in the dosing chamber, and a first metering pump controlled by the PLC control box is mounted at the defoaming agent inlet; the PLC control box is used for receiving detection data of the optical sensor of the first detection chamber, calculating the adding amount of a required defoaming agent and controlling the first metering pump to add the defoaming agent; the technical problem that in the prior art, a defoaming agent filling mode is unreasonable is solved.

Description

Technical Field

[0001] The invention relates to the technical field of shale gas produced water pretreatment, and in particular to a defoaming device for a shale gas produced water pretreatment section. Background Art

[0002] Shale gas is an important unconventional natural gas resource, and its extraction process is accompanied by the generation of a large amount of produced water. In order to improve the production efficiency of gas wells, wellhead drainage gas production technology is widely used. One of the key technologies is to use foaming agents as liquid surfactants. Foaming agents can effectively reduce the surface tension of water and enhance the fluidity of water, which helps to more effectively discharge the accumulated water in the gas well, thereby maintaining the efficient production of the gas well.

[0003] At present, the foaming agent used in drainage and gas production operations in some gas wells cannot be fully eliminated in the produced water due to the unreasonable concentration ratio of the defoaming agent when it enters the subsequent treatment process with the produced water. This problem is particularly prominent when the produced water enters the evaporation and crystallization treatment stage. The foaming agent that is not completely eliminated quickly forms a large number of bubbles in the forced evaporator. These bubbles not only occupy the effective space in the evaporator, causing the so-called "top tank" phenomenon, but also seriously interfere with the accurate reading of the liquid level meter, resulting in false liquid level reports, which in turn poses a threat to the stable operation of the entire evaporation and crystallization system.

[0004] The existing defoamer filling method is mostly manual operation, that is, the defoamer is manually carried to the top of the clarification tank in the pretreatment section for filling. This method is not only labor-intensive and inefficient, but also in the actual filling process, it is often difficult to achieve accurate dosage control and uniform distribution, resulting in concentrated addition of defoamers in a period of time, which frequently causes bubble problems in the evaporation crystallization system, seriously affecting the continuity and stability of the system. Summary of the invention

[0005] The present invention is intended to provide a defoaming device for a shale gas produced water pretreatment stage, so as to solve the unreasonable technical problem of the defoaming agent injection method in the prior art.

[0006] To achieve the above-mentioned object, the present invention adopts the following technical scheme: a defoaming device for the pretreatment section of shale gas produced water, comprising a first detection chamber, a dosing chamber, a temporary storage chamber for temporarily storing raw water after dosing, a water distribution chamber for outputting raw water at high speed, a clarification chamber for clarifying raw water and a PLC control box, wherein the first detection chamber, the dosing chamber, the temporary storage chamber, the water distribution chamber and the clarification chamber are connected in sequence;

[0007] The first detection chamber includes a water inlet for providing raw water and a water outlet connected to the dosing chamber. An optical sensor for detecting the foam content in the raw water is provided in the first detection chamber. The optical sensor is connected to the PLC control box through a signal line and transmits detection data to the PLC control box.

[0008] A defoaming agent inlet is arranged in the dosing chamber, and a first metering pump controlled by a PLC control box is installed at the defoaming agent inlet; the PLC control box receives the detection data of the optical sensor in the first detection chamber, calculates the required amount of defoaming agent to be added, and controls the first metering pump to add the defoaming agent.

[0009] The principles and advantages of this solution are: in actual application, the foam content in the raw water is detected in real time by the optical sensor in the first detection chamber, and the data is transmitted to the PLC control box; the PLC control box accurately calculates the required amount of defoaming agent to be added based on the received data, and realizes automatic and precise defoaming agent filling by controlling the first metering pump; this method not only solves the problems of unreasonable defoaming agent filling method and difficult dosage control in the prior art, but also significantly improves the defoaming efficiency, reduces the waste of defoaming agent, and reduces the processing cost; at the same time, the automatic filling method also greatly reduces the labor intensity and improves the work efficiency; the defoaming agent filling process is set in the clarification process, so that the defoaming agent can be fully mixed with the foaming agent in the clarification process to play a role.

[0010] Preferably, as an improvement, the defoaming device further comprises a second detection chamber, the water inlet of the second detection chamber is connected to the water outlet of the clarifying chamber, a conductivity sensor for detecting the foam content in the clarified water is arranged in the second detection chamber, the conductivity sensor is connected to the PLC control box via a signal line, and transmits detection data to the PLC control box;

[0011] The second detection chamber is provided with a defoaming agent inlet, at which a second metering pump controlled by a PLC control box is installed; the PLC control box receives detection data from the optical sensor of the second detection chamber, calculates the required amount of defoaming agent added, and controls the second metering pump to add the defoaming agent.

[0012] The beneficial effect of this improvement is that through secondary testing, it can ensure that the foam content in the clarified water meets the required standards, avoiding the effects of subsequent treatment processes and product quality affected by residual bubbles; at the same time, the PLC control box can further accurately control the filling amount of the second metering pump based on the data from the second testing room, realize secondary replenishment of the defoaming agent, and ensure that the defoaming effect is always maintained in the best state.

[0013] Preferably, as an improvement, the water outlet of the temporary storage chamber is connected to the water distribution chamber through a pipeline; a pulse metering pump is provided in the pipeline between the temporary storage chamber and the water distribution chamber, and the pulse metering pump is controlled by a timer;

[0014] A high-pressure gas inlet is provided in the water distribution chamber, and the high-pressure gas inlet is connected to a pressure regulator for filling with high-pressure gas; the water distribution chamber is also provided with an exhaust valve; the water distribution chamber is also provided with a water outlet, and the water outlet of the water distribution chamber is connected with the clarification chamber through a pipeline, and a water distribution pump for high-speed transportation of raw water is installed at the water outlet.

[0015] The beneficial effects of this improvement are: the precise control of the pulse metering pump can ensure the stable supply and uniform distribution of raw water; the breaking effect of the high-pressure gas can quickly reduce the stability and volume of the foam, creating favorable conditions for subsequent clarification treatment.

[0016] Preferably, as an improvement, the defoaming device also includes a first agent dilution tank and a second agent dilution tank, the first agent dilution tank is connected to the defoaming agent inlet of the dosing chamber, and the second agent dilution tank is connected to the defoaming agent inlet of the second detection chamber; the defoaming agent concentration in the first agent dilution tank is higher than the defoaming agent concentration in the second agent dilution tank.

[0017] The beneficial effect of this improvement is that by distinguishing defoamer dilution tanks of different concentrations, the concentration of the defoamer can be flexibly adjusted according to actual needs to achieve a more accurate defoaming effect. At the same time, it also helps to reduce the waste of defoamers and environmental pollution.

[0018] Preferably, as an improvement, the dosing chamber is also provided with inlets for coagulants and coagulant aids, the clarification chamber is provided with a sludge layer, an inclined pipe and a water collecting trough from bottom to top, and a perforated water distribution pipe is provided at the bottom of the clarification chamber, which is connected to the water outlet of the water distribution chamber.

[0019] The beneficial effects of this improvement are: the addition of coagulants and coagulant aids helps to accelerate the collapse of foam and the settling of suspended matter; the synergistic effect of the sludge layer, inclined pipes and water collection tanks further improves the clarification effect and ensures the water quality of the clarified water.

[0020] Preferably, as an improvement, the defoaming device also includes a reagent storage tank for storing high-concentration defoaming agent and a clean water storage tank for storing clean water, and both the reagent storage tank and the clean water storage tank are connected to the first reagent dilution tank and the second reagent dilution tank.

[0021] The beneficial effect of this improvement is that the addition of a reagent storage tank and a clean water storage tank provides convenience for the replenishment of defoaming agent and clean water, ensuring the continuous and stable operation of the defoaming device. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic structural diagram of an embodiment of the present invention. DETAILED DESCRIPTION

[0023] The following is further described in detail through specific implementation methods:

[0024] The figure marks in the drawings of the specification include: a first detection chamber 1, a dosing chamber 2, a temporary storage chamber 3, a water distribution chamber 4, a clarification chamber 5, a second detection chamber 6, a drug storage tank 7, a clean water storage tank 8, a first drug dilution tank 9 and a second drug dilution tank 10.

[0025] Example

[0026] Basically as attached Figure 1 As shown, a defoaming device for the pretreatment stage of shale gas produced water includes a first detection chamber 1, a dosing chamber 2, a temporary storage chamber 3, a water distribution chamber 4, a clarification chamber 5, a second detection chamber 6, a reagent storage tank 7, a clean water storage tank 8 and a PLC control box. The raw water flows to the subsequent evaporation and crystallization process after passing through the first detection chamber 1, the dosing chamber 2, the temporary storage chamber 3, the water distribution chamber 4, the clarification chamber 5 and the second detection chamber 6 in sequence.

[0027] The first detection chamber 1 is used to detect the foam content in the raw water. The first detection chamber 1 includes a water inlet and a water outlet. The water inlet continuously provides stable raw water to the first detection chamber 1. The water outlet of the first detection chamber 1 is arranged at the bottom of the first detection chamber 1 and is connected to the dosing chamber 2 through a pipeline. An optical sensor is installed on the inner wall of the first detection chamber 1. The installation height of the optical sensor is higher than the highest liquid level of the first detection chamber 1. The optical sensor projects a light beam onto the raw water by emitting a light source, and then receives the reflected light beam through a receiver located on the opposite side. The optical sensor is connected to the PLC control box through a signal line to transmit the detection data. The PLC control box analyzes and determines the amount of foam and density of the raw water in the first detection chamber 1 by the intensity of the received light signal.

[0028] The dosing chamber 2 is connected to the first detection chamber 1 and receives raw water from the first detection chamber 1. A stirring assembly is provided in the dosing chamber 2, which is located in the center of the chamber and driven by a motor. A defoaming agent inlet is provided at the top of the dosing chamber 2, which is connected to the first agent dilution tank 9 through a pipeline. A first metering pump is installed at the inlet and controlled by a PLC control box. A water outlet is provided at the bottom of the dosing chamber 2, which is connected to the temporary storage chamber 3 through a pipeline.

[0029] The temporary storage chamber 3 receives the raw water after the dosing from the dosing chamber 2. The top of the temporary storage chamber 3 is provided with an exhaust port, and the bottom is provided with a water outlet. The water outlet of the temporary storage chamber 3 is connected to the water distribution chamber 4 through a pipeline. A pulse metering pump is provided in the pipeline between the temporary storage chamber 3 and the water distribution chamber 4. The pulse metering pump is controlled by a timer and periodically supplies a fixed amount of raw water to the water distribution chamber 4.

[0030] The water distribution chamber 4 receives the raw water from the temporary storage chamber 3. A high-pressure gas inlet is provided at the top of the inner wall of the water distribution chamber 4, which is connected to a pressure regulator and is used to fill high-pressure gas to break the foam. An exhaust valve is also provided at the top of the water distribution chamber 4 for pressure relief. A water outlet is provided at the bottom of the water distribution chamber 4, which is connected to the clarification chamber 5 through a pipeline, and a water distribution pump is installed at the water outlet. The water distribution pump delivers the raw water in the water distribution chamber 4 to the clarification chamber 5 at a high speed to form a pulsed water flow.

[0031] The clarification chamber 5 receives the raw water from the water distribution chamber 4. The raw water entering the clarification chamber 5 in pulsed manner forms a sludge layer in a pulsed rising and falling state in the clarification chamber 5, thereby clarifying the raw water. The clarification chamber 5 is provided with a sludge layer, an inclined pipe and a water collection tank from bottom to top. A perforated water distribution pipe is provided at the bottom of the clarification chamber 5, which is connected to the water outlet of the water distribution chamber 4. A water outlet is provided at one end of the water collection tank at the top of the clarification chamber 5, which is connected to the second detection chamber through a pipeline.

[0032] The second detection chamber receives clarified water from the clarification chamber 5. A conductivity sensor is provided in the chamber, and the conductivity sensor measures the conductivity value of the clarified water in the second detection chamber 6. The conductivity sensor is connected to the PLC control box through a signal line. The conductivity sensor sends the detected conductivity value to the PLC control box, and the PLC control box determines whether it is necessary to add a defoaming agent to the second detection and the amount of the defoaming agent to be added according to the conductivity value. A water outlet is provided at the bottom of the second detection chamber, which is connected to the subsequent evaporation and crystallization process through a pipeline. A defoaming agent inlet is provided at the top of the second detection chamber, which is connected to the second agent dilution tank 10 through a pipeline. A second metering pump is installed at the inlet, which is controlled by the PLC control box.

[0033] The reagent storage tank 7 and the clean water storage tank 8 are used to store high-concentration defoaming agent and clean water respectively. Both tanks are connected to the first reagent dilution tank 9 and the second reagent dilution tank 10 for supplementing or adjusting the reagent concentration.

[0034] The connecting pipes between the chambers are all equipped with flange connections for easy disassembly and maintenance. The installation positions of the optical sensor and the conductivity sensor are all away from the direct impact area of ​​the fluid to ensure accurate measurement. The stirring assembly is located in the center of the dosing chamber 2 to ensure that the reagent and the raw water are fully mixed. The pressure regulator and the exhaust valve are both located at the top of the water distribution chamber 4 for easy operation and observation. The perforated water distribution pipes are evenly distributed at the bottom of the clarification chamber 5 to ensure even distribution of the water flow.

[0035] The PLC control box is connected to the optical sensor, conductivity sensor, first metering pump, second metering pump, pulse metering pump, pressure regulator and exhaust valve through signal lines. The PLC control box receives the detection data from the sensor and processes and analyzes it. According to the analysis results and the preset workflow rules, the PLC control box controls the actions of each actuator to realize the automatic operation of the device. The PLC control box is also equipped with a touch screen human-machine interface, which is convenient for operators to monitor the operating status of the device and set parameters.

[0036] The specific implementation process of the device is as follows:

[0037] Raw water containing foaming agent or foam enters the first detection chamber 1 to prepare for subsequent foam detection and defoaming treatment. The optical sensor uses the principle of light beam projection and reflection to accurately detect the foam content in the raw water. The detection data is transmitted to the PLC control box in real time to provide an accurate basis for the calculation of the subsequent defoaming agent addition. By accurately detecting the foam content, it can be ensured that the amount of defoaming agent added is neither excessive nor insufficient, thereby saving the cost of the agent and avoiding unnecessary pollution to the environment.

[0038] The PLC control box calculates the required amount of defoamer to be added through a preset algorithm based on the received foam content data. The first metering pump is controlled to accurately add the calculated defoamer amount to the dosing chamber 2. Accurately controlling the amount of defoamer added can ensure the best defoaming effect while avoiding waste of agents. At the same time, the dosing chamber 2 also mixes a certain amount of coagulant and coagulant aid into the raw water. The addition of coagulant and coagulant aid helps to accelerate the rupture of foam and the sedimentation of suspended matter.

[0039] The stirring assembly in the dosing chamber 2 fully mixes the defoaming agent with the raw water. Full mixing can ensure the uniform distribution of the agent in the raw water, thereby improving the defoaming and clarification effects. The mixed raw water enters the temporary storage chamber 3 for temporary storage, waiting for the pulse metering pump to periodically supply it to the water distribution chamber 4.

[0040] The mixed raw water enters the temporary storage chamber 3 through the pipeline for temporary storage. The temporary storage chamber 3 plays a role of buffering and storage to ensure the continuity and stability of the subsequent treatment process. The setting of the temporary storage chamber 3 can ensure the continuous supply of raw water during the treatment process and avoid affecting the treatment effect due to flow fluctuations.

[0041] The pulse metering pump supplies raw water to the water distribution chamber 4 according to a preset cycle and flow rate. The precise control of the pulse metering pump can ensure a stable supply and uniform distribution of raw water.

[0042] The pressure regulator fills the water distribution chamber 4 with high-pressure gas through the high-pressure gas pipeline. The high-pressure gas causes the foam in the water distribution chamber 4 to break up quickly and disperse into tiny bubbles. The breaking effect of the high-pressure gas can quickly reduce the stability and volume of the foam, creating favorable conditions for subsequent clarification treatment.

[0043] After the air pressure reaches the threshold, it stays for a certain period of time and is released by the exhaust valve. After the pressure is released, the water distribution pump is started to inject the water in the water distribution chamber 4 into the bottom of the clarification chamber 5 at high speed through the perforated water distribution pipe.

[0044] The water in the clarification chamber 5 is settled and filtered under the combined action of the sludge layer, the inclined tube and the water collection tank. The sludge layer can intercept larger suspended matter and impurities; the inclined tube can accelerate the settling of fine particles; and the water collection tank collects and discharges the treated clarified water.

[0045] The clarified water enters the second detection chamber through the pipeline for secondary detection. The conductivity sensor uses the conductivity principle to detect the density and content of bubbles in the clarified water. The secondary detection can ensure that the bubble content in the clarified water meets the required standards to avoid the residual bubbles affecting the effect of the subsequent treatment process and product quality. The PLC control box analyzes and judges based on the received secondary detection data. If the test results show that the bubble content in the clarified water is still high, the PLC control box controls the second metering pump to add the corresponding metered defoaming agent to the second detection chamber for supplementary treatment. The secondary detection and supplementary treatment can ensure that the bubble content in the clarified water is always kept at a low level, thereby further improving the water quality and the effect of the subsequent treatment process.

[0046] After secondary testing and adjustment, the clarified water flows to the subsequent evaporation and crystallization process for further treatment.

[0047] The above is only an embodiment of the present invention, and the common knowledge such as the known specific technical solutions and / or characteristics in the solution is not described in detail here. It should be pointed out that for those skilled in the art, without departing from the technical solution of the present invention, several modifications and improvements can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A defoaming device for shale gas produced water pretreatment stage, characterized in that: It includes a first detection room, a dosing room, a temporary storage room for temporarily storing raw water after dosing, a water distribution room for high-speed output of raw water, a clarification room for clarifying raw water and a PLC control box. The first detection room, the dosing room, the temporary storage room, the water distribution room and the clarification room are connected in sequence; The first detection chamber includes a water inlet for providing raw water and a water outlet connected to the dosing chamber. An optical sensor for detecting the foam content in the raw water is provided in the first detection chamber. The optical sensor is connected to the PLC control box through a signal line and transmits detection data to the PLC control box. A defoaming agent inlet is arranged in the dosing chamber, and a first metering pump controlled by a PLC control box is installed at the defoaming agent inlet; the PLC control box receives the detection data of the optical sensor in the first detection chamber, calculates the required amount of defoaming agent to be added, and controls the first metering pump to add the defoaming agent.

2. A defoaming device for shale gas produced water pretreatment stage according to claim 1, characterized in that: The defoaming device also includes a second detection chamber, the water inlet of the second detection chamber is connected to the water outlet of the clarification chamber, and a conductivity sensor for detecting the foam content in the clarified water is arranged in the second detection chamber. The conductivity sensor is connected to the PLC control box through a signal line and transmits detection data to the PLC control box; The second detection chamber is provided with a defoaming agent inlet, at which a second metering pump controlled by a PLC control box is installed; the PLC control box receives detection data from the optical sensor of the second detection chamber, calculates the required amount of defoaming agent added, and controls the second metering pump to add the defoaming agent.

3. A defoaming device for shale gas produced water pretreatment stage according to claim 2, characterized in that: The water outlet of the temporary storage chamber is connected to the water distribution chamber through a pipeline; a pulse metering pump is arranged in the pipeline between the temporary storage chamber and the water distribution chamber, and the pulse metering pump is controlled by a timer; A high-pressure gas inlet is provided in the water distribution chamber, and the high-pressure gas inlet is connected to a pressure regulator for filling with high-pressure gas; the water distribution chamber is also provided with an exhaust valve; the water distribution chamber is also provided with a water outlet, and the water outlet of the water distribution chamber is connected with the clarification chamber through a pipeline, and a water distribution pump for high-speed transportation of raw water is installed at the water outlet.

4. A defoaming device for shale gas produced water pretreatment stage according to claim 3, characterized in that: The defoaming device also includes a first agent dilution tank and a second agent dilution tank. The first agent dilution tank is connected to the defoaming agent inlet of the dosing chamber, and the second agent dilution tank is connected to the defoaming agent inlet of the second detection chamber. The defoaming agent concentration in the first agent dilution tank is higher than the defoaming agent concentration in the second agent dilution tank.

5. A defoaming device for shale gas produced water pretreatment stage according to claim 4, characterized in that: The dosing chamber is also provided with inlets for coagulants and coagulant aids. The clarification chamber is provided with a sludge layer, an inclined pipe and a water collecting tank from bottom to top. A perforated water distribution pipe is provided at the bottom of the clarification chamber and is connected with the water outlet of the water distribution chamber.

6. A defoaming device for shale gas produced water pretreatment stage according to claim 5, characterized in that: The defoaming device further comprises a medicine storage tank for storing high-concentration defoaming agent and a clean water storage tank for storing clean water. Both the medicine storage tank and the clean water storage tank are connected to the first medicine dilution tank and the second medicine dilution tank.

Images