A defoaming device for a shale gas produced water pretreatment section

Abstract

The present application relates to the technical fields of shale gas production water pretreatment, and discloses a defoaming device for shale gas production water pretreatment section, which comprises a first detection chamber, a dosing chamber and a PLC control box, the first detection chamber comprises a water inlet for providing raw water and a separated water outlet communicated with the dosing chamber, an optical sensor for detecting the content of foam in the raw water is arranged in the first detection chamber, the optical sensor 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 arranged in the dosing chamber, a first metering pump controlled by the PLC control box is installed at the defoaming agent inlet, the PLC control box receives the detection data of the optical sensor of the first detection chamber, calculates the required addition amount of defoaming agent, and controls the first metering pump to add the defoaming agent, so as to solve the technical problem of unreasonable defoaming agent filling mode in the prior art.

Description

Technical Field

[0001] This invention relates to the field of shale gas produced water pretreatment technology, specifically to a defoaming device for a shale gas produced water pretreatment section. Background Technology

[0002] Shale gas, as an important unconventional natural gas resource, generates a large amount of produced water during its extraction. To improve the production efficiency of gas wells, wellhead drainage gas production technology is widely used, and one key technology is the use of foaming agents as liquid surfactants. By effectively reducing the surface tension of water and enhancing its fluidity, foaming agents help to more effectively drain water from the gas well, thereby maintaining high-efficiency production.

[0003] Currently, in some gas wells, the foaming agents used in drainage and gas production operations fail to fully eliminate their components in the produced water when it enters subsequent treatment processes due to improper defoamer concentration ratios. This problem is particularly prominent when the produced water enters the evaporation and crystallization stage, where incompletely eliminated foaming agent rapidly forms numerous bubbles in the forced evaporator. These bubbles not only occupy the effective space within the evaporator, causing the so-called "top-tank" phenomenon, but also severely interfere with the accurate readings of the level gauge, leading to false level alarms, and thus threatening the stable operation of the entire evaporation and crystallization system.

[0004] Existing methods for adding defoamers mostly involve manual operation, where the defoamer is manually transported to the clarification tank in the pretreatment section for addition. This method is not only labor-intensive and inefficient, but also often results in the concentrated addition of defoamer within a short period due to the difficulty in achieving precise dosage control and uniform distribution. This leads to frequent bubble formation in the evaporation and crystallization system, severely affecting the system's continuity and stability. Summary of the Invention

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

[0006] To achieve the above objectives, the present invention adopts the following technical solution: 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 the raw water after dosing, a water distribution chamber for high-speed output of the raw water, a clarification chamber for clarifying the 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 an inlet for supplying raw water and an outlet connected to the dosing chamber. The first detection chamber is equipped with an optical sensor for detecting the foam content in the raw water. The optical sensor is connected to the PLC control box via a signal line and transmits detection data to the PLC control box.

[0008] The dosing chamber is equipped with an antifoaming agent inlet, and a first metering pump controlled by a PLC control box is installed at the antifoaming agent inlet. The PLC control box receives the detection data from the optical sensor in the first detection chamber, calculates the required amount of antifoaming agent to be added, and controls the first metering pump to add antifoaming agent.

[0009] The principle and advantages of this solution are as follows: In practical 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. Based on the received data, the PLC control box accurately calculates the required amount of defoamer to be added, and realizes automated and precise defoamer dosing by controlling the first metering pump. This method not only solves the problems of unreasonable defoamer dosing and difficult dosage control in the existing technology, but also significantly improves defoaming efficiency, reduces defoamer waste, and lowers treatment costs. At the same time, the automated dosing method also greatly reduces the intensity of manual labor and improves work efficiency. Setting the defoamer dosing process in the clarification process allows the defoamer to be fully mixed with the foaming agent in the clarification process to play its role.

[0010] Preferably, as an improvement, the defoaming device further includes a second detection chamber, the inlet of which is connected to the outlet of the clarification chamber. The second detection chamber is equipped with a conductivity sensor for detecting the foam content in the clarified water. 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 testing chamber is equipped with a defoamer inlet, and a second metering pump controlled by a PLC control box is installed at the defoamer inlet. The PLC control box receives the detection data from the optical sensor in the second testing chamber, calculates the required amount of defoamer to be added, and controls the second metering pump to add defoamer.

[0012] The beneficial effects of this improvement are: secondary testing ensures that the foam content in the clarified water meets the required standards, avoiding the impact of residual bubbles on the effectiveness of subsequent processing steps and product quality; at the same time, the PLC control box can further precisely control the dosing amount of the second metering pump based on the data from the second testing chamber, realizing secondary replenishment of defoamer and ensuring that the defoaming effect is always kept at its best.

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

[0014] The water distribution chamber is equipped with a high-pressure gas inlet, which is connected to a pressure regulator for charging high-pressure gas; the water distribution chamber is also equipped with an air vent valve; the water distribution chamber is also equipped with a water outlet, which is connected to the clarification chamber through a pipe, 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 a stable supply and uniform distribution of raw water; the breaking effect of high-pressure gas can rapidly reduce the stability and volume of foam, creating favorable conditions for subsequent clarification treatment.

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

[0017] The benefits of this improvement are: by using separate dilution tanks for different concentrations of defoamer, the concentration of the defoamer can be flexibly adjusted according to actual needs, achieving a more precise defoaming effect. At the same time, it also helps reduce waste of defoamer and environmental pollution.

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

[0019] The beneficial effects of this improvement are: the addition of coagulants and flocculants helps to accelerate the breaking of foam and the settling of suspended solids; the synergistic effect of the sludge layer, inclined tubes and collection tank further improves the clarification effect and ensures the quality of the clarified water.

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

[0021] The beneficial effects of this improvement are: the addition of the chemical storage tank and the clean water storage tank facilitates the replenishment of defoamer and clean water, ensuring the continuous and stable operation of the defoaming device. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of an embodiment of the present invention. Detailed Implementation

[0023] The following detailed description illustrates the specific implementation method:

[0024] The reference numerals in the accompanying drawings include: First detection chamber 1, dosing chamber 2, temporary storage chamber 3, water distribution chamber 4, clarification chamber 5, Second detection chamber 6, reagent storage tank 7, clean water storage tank 8, first reagent dilution tank 9, and second reagent dilution tank 10.

[0025] Example

[0026] The basics are as follows: Figure 1 As shown, a defoaming device for the pretreatment section 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 sequentially passes 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 before flowing to the subsequent evaporation and crystallization process.

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

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

[0029] The temporary storage chamber 3 receives raw water after chemical dosing from the chemical dosing chamber 2. The temporary storage chamber 3 has an exhaust vent at the top and a water outlet at the bottom. The water outlet of the temporary storage chamber 3 is connected to the water distribution chamber 4 via a pipe. A pulse metering pump is installed in the pipe 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] Water distribution chamber 4 receives raw water from storage chamber 3. A high-pressure gas inlet, connected to a pressure regulator, is located at the top of the inner wall of water distribution chamber 4 to allow high-pressure gas to be introduced to break up foam. An air vent valve is also located at the top of water distribution chamber 4 for pressure relief. An outlet is located at the bottom of water distribution chamber 4, connected to clarification chamber 5 via a pipe. A water distribution pump is installed at the outlet. The water distribution pump delivers the raw water from water distribution chamber 4 into clarification chamber 5 at high speed, creating a pulsed water flow.

[0031] Clarification chamber 5 receives raw water from distribution chamber 4. The pulsed inflow of raw water into clarification chamber 5 creates a sludge layer that rises and falls in a pulsed manner, thus clarifying the raw water. From bottom to top, clarification chamber 5 contains a sludge layer, an inclined pipe, and a collection trough. A perforated distribution pipe is located at the bottom of clarification chamber 5, connecting to the outlet of distribution chamber 4. One end of the collection trough at the top of clarification chamber 5 has an outlet, which connects to the second detection chamber via a pipe.

[0032] The second testing chamber receives clarified water from clarification chamber 5. A conductivity sensor is installed in this chamber to measure the conductivity of the clarified water. The sensor is connected to a PLC control box via a signal line, transmitting the detected conductivity value. The PLC control box then determines whether defoamer needs to be added to the second testing chamber and, if so, the amount. An outlet is located at the bottom of the second testing chamber, connected to the subsequent evaporation and crystallization process via a pipe. An defoamer inlet is located at the top of the second testing chamber, connected to the second reagent dilution tank 10 via a pipe. A second metering pump is installed at the inlet and controlled by the PLC control box.

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

[0034] All connecting pipes between chambers are equipped with flange connections for easy disassembly and maintenance. The optical and conductivity sensors are installed away from areas directly impacted by the fluid to ensure accurate measurements. The stirring assembly is located in the center of the dosing chamber 2 to ensure thorough mixing of the reagents and raw water. The pressure regulator and vent valve are located at the top of the distribution chamber 4 for easy operation and observation. Perforated distribution pipes are evenly distributed at the bottom of the clarification chamber 5 to ensure uniform water flow.

[0035] The PLC control box connects to optical sensors, conductivity sensors, the first metering pump, the second metering pump, the pulse metering pump, the pressure regulator, and the exhaust valve via signal lines. The PLC control box receives detection data from the sensors and processes and analyzes it. Based on the analysis results and preset workflow rules, the PLC control box controls the actions of each actuator to achieve automatic operation of the device. The PLC control box also features a touchscreen human-machine interface, facilitating operator monitoring of the device's operating status and parameter settings.

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

[0037] Raw water containing foaming agents or foam enters the first detection chamber 1 to prepare for subsequent foam detection and defoaming treatment. Optical sensors utilize the principles of beam projection and reflection to accurately detect the foam content in the raw water. The detection data is transmitted in real-time to the PLC control box, providing an accurate basis for calculating the subsequent defoamer dosage. By accurately detecting the foam content, it can be ensured that the amount of defoamer added is neither excessive nor insufficient, thereby saving on reagent costs and avoiding unnecessary environmental pollution.

[0038] The PLC control box calculates the required amount of defoamer to be added based on the received foam content data using a preset algorithm. It then controls the first metering pump to precisely add the calculated defoamer dosage to the dosing chamber 2. Precise control of the defoamer dosage ensures optimal defoaming effect while avoiding waste. Simultaneously, the dosing chamber 2 also mixes a certain amount of coagulant and flocculant aid into the raw water. The addition of coagulant and flocculant aid helps accelerate foam breakdown and suspended solids settling.

[0039] The stirring assembly in dosing chamber 2 thoroughly mixes the defoamer with the raw water. Thorough mixing ensures uniform distribution of the agent in the raw water, thereby improving defoaming and clarification effects. The mixed raw water is then temporarily stored in storage chamber 3, awaiting periodic supply to distribution chamber 4 by the pulse metering pump.

[0040] After thorough mixing, the raw water enters the temporary storage chamber 3 through pipelines for temporary storage. The temporary storage chamber 3 serves as a buffer and storage unit, ensuring the continuity and stability of subsequent treatment processes. The temporary storage chamber 3 ensures a continuous supply of raw water during treatment, preventing fluctuations in flow rate from affecting the treatment effect.

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

[0042] The pressure regulator injects high-pressure gas into the water distribution chamber 4 through a high-pressure gas pipeline. The high-pressure gas causes the foam in the water distribution chamber 4 to break down rapidly and disperse into tiny bubbles. The breaking action 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 remains for a certain period of time before being released by the vent valve. After the pressure is released, the water distribution pump starts, injecting water from the water distribution chamber 4 into the bottom of the clarification chamber 5 at high speed through the perforated water distribution pipe.

[0044] In clarification chamber 5, the water undergoes sedimentation and filtration through the combined action of the sludge layer, inclined tubes, and collection tank. The sludge layer traps larger suspended solids and impurities; the inclined tubes accelerate the sedimentation of fine particles; and the collection tank collects and discharges the treated clarified water.

[0045] Clarified water enters a secondary testing chamber through pipelines for secondary testing. A conductivity sensor uses the principle of conductivity to detect the density and content of air bubbles in the clarified water. This secondary testing ensures that the bubble content in the clarified water meets the required standards, preventing residual bubbles from affecting the effectiveness of subsequent treatment processes and product quality. The PLC control box analyzes and judges the received secondary testing 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 appropriate amount of defoamer to the secondary testing chamber for supplementary treatment. This secondary testing and supplementary treatment ensures that the bubble content in the clarified water remains at a low level, thereby further improving water quality and the effectiveness of subsequent treatment processes.

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

[0047] The above descriptions are merely embodiments of the present invention, and common knowledge such as specific technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A defoaming device for a shale gas produced water pretreatment stage, characterized by: The device comprises a first detection chamber, a dosing chamber, a temporary storage chamber for temporarily storing raw water after dosing, a water distribution chamber for high-speed output of raw water, a clarification chamber for clarifying raw water, and a PLC control box, and the first detection chamber, the dosing chamber, the temporary storage chamber, the water distribution chamber, and the clarification chamber are sequentially communicated. The first detection chamber comprises a water inlet for providing raw water and a water outlet communicated with the dosing chamber, and an optical sensor for detecting the content of foam in raw water is arranged in the first detection chamber, and the optical sensor 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 arranged in the dosing chamber, and a first metering pump controlled by the PLC control box is arranged at the defoaming agent inlet; the PLC control box receives the detection data of the optical sensor of 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. The device further comprises a second detection chamber, a water inlet of the second detection chamber is communicated with a water outlet of the clarification chamber, and a conductivity sensor for detecting the content of foam in clarified water is arranged in the second detection chamber, and the conductivity sensor is connected with 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, and a second metering pump controlled by the PLC control box is arranged at the defoaming agent inlet; the PLC control box receives the detection data of the optical sensor of the second detection chamber, calculates the required amount of defoaming agent to be added, and controls the second metering pump to add the defoaming agent. The water outlet of the temporary storage chamber is communicated with 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 arranged in the water distribution chamber, and a pressure regulator for filling high-pressure gas is connected to the high-pressure gas inlet; the water distribution chamber is further provided with an exhaust valve; the water distribution chamber is further provided with a water outlet, and the water outlet of the water distribution chamber is communicated with the clarification chamber through a pipeline, and a water distribution pump for high-speed conveying of raw water is arranged at the water outlet.

2. A defoaming device for a shale gas produced water pre-treatment stage according to claim 1, characterized in that: The device further comprises a first medicament dilution tank and a second medicament dilution tank, the first medicament dilution tank is communicated with the defoaming agent inlet of the dosing chamber, and the second medicament dilution tank is communicated with the defoaming agent inlet of the second detection chamber; the concentration of defoaming agent in the first medicament dilution tank is higher than that in the second medicament dilution tank.

3. A defoaming device for a shale gas produced water pre-treatment stage according to claim 2, characterised in that: The dosing chamber is further provided with inlets of coagulant and coagulant aid, and the clarification chamber is sequentially provided with a sludge layer, a sludge pipe, and a water collecting tank from bottom to top, and the clarification chamber is provided with a perforated water distribution pipe communicated with the water outlet of the water distribution chamber.

4. A defoaming device for a shale gas produced water pre-treatment stage according to claim 3, characterized in that: The device further comprises a medicament storage tank for storing high-concentration defoaming agent and a clean water storage tank for storing clean water, and the medicament storage tank and the clean water storage tank are communicated with the first medicament dilution tank and the second medicament dilution tank.

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