JP2014164517A - Medicine addition amount control method and medicine addition amount control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a medicine addition amount control method and a medicine addition amount control device capable of shortening time required for adjusting an amount of addition of medicine to a proper amount.SOLUTION: A medicine addition amount control method is for controlling an amount of addition of medicine to be added to liquid so that the residual concentration at a target spot becomes equal to or more than target concentration at an entrance of a reaction zone, and has: a residual concentration calculation step (S50) of calculating secular change of the residual concentration of the medicine at the target spot when the medicine is added with arbitrary concentration A in the case of assuming that the reaction zone is a perfect mixing type and no medicine is consumed; a residual concentration measurement step (S30) of measuring the secular change of the residual concentration of the medicine at the target spot when the medicine is actually added with the concentration A; and a medicine addition amount determination step (S60) of determining the amount of addition of the medicine based on a residual concentration calculation value in the residual concentration calculation step at a point of time when the residual concentration of the medicine measured in the residual concentration measurement step reaches or is presumed to reach the target concentration.

Description

  The present invention relates to a drug addition amount control method and a drug addition amount control apparatus.

  Conventionally, there is a technique for controlling the amount of drug added. For example, in Patent Document 1, a liquid in a line to which a predetermined amount of sodium hypochlorite is supplied from a chemical supply device is sampled, and the attenuation of the sodium hypochlorite concentration in the sampled sample is measured. Disclosed is a ballast water control method including adjusting the amount of sodium hypochlorite supplied to a line from a chemical supply device based on data, and a ballast water treatment system using the control method. Yes.

JP 2012-106224 A

  There is still room for improvement in the control of the amount of drug added. For example, it is desired to be able to shorten the time required to adjust the added amount of the drug to an appropriate amount.

  The objective of this invention is providing the chemical | medical agent addition amount control method and chemical | medical agent addition amount control apparatus which can shorten the time required in order to adjust the addition amount of a chemical | medical agent to an appropriate amount.

  In the method for controlling the amount of added drug according to the present invention, the amount of drug added to the liquid at the entrance of the reaction zone through which the liquid flows is determined, and the residual concentration of the drug at the target point on the flow path of the liquid is the target concentration. (1) When it is assumed that the reaction zone is a complete mixing type and there is no consumption of the drug in the reaction zone, the drug is added to any desired concentration above the target concentration. A residual concentration calculating step for calculating a change over time in the residual concentration of the drug at the target point when added at the concentration A; and (2) at the target point when the drug is actually added at the concentration A. A residual concentration measurement step for measuring a change over time in the residual concentration of the drug; and (3) the residual concentration of the drug measured in the residual concentration measurement step reaches the target concentration or A drug addition amount determining step of obtaining a residual concentration calculation value in the residual concentration calculation step at a time point corresponding to a time point estimated to have reached, and determining an addition amount of the drug based on the calculation value. Features.

  The chemical addition amount control device of the present invention is configured such that the amount of chemical added to the liquid at the entrance of the reaction zone through which the liquid flows is determined by the residual concentration of the chemical at the target point on the flow path of the liquid. (1) When it is assumed that the reaction zone is a complete mixing type and there is no consumption of the drug in the reaction zone, the drug is set to an arbitrary concentration equal to or higher than the target concentration. A residual concentration calculating means for calculating a change over time in the residual concentration of the drug at the target point when added at the concentration A; and (2) at the target point when the drug is actually added at the concentration A. A residual concentration measuring means for measuring a change over time in the residual concentration of the medicine; and (3) the residual concentration of the medicine measured by the residual concentration measuring means reaches the target concentration or And a drug addition amount control means for obtaining a residual concentration calculation value by the residual concentration calculation means at a time point corresponding to a time point estimated to have reached, and controlling the addition amount of the drug based on the calculation value. And

  In the method for controlling the amount of added drug according to the present invention, the amount of added drug added to the liquid at the entrance of the reaction zone through which the liquid flows is determined so that the residual concentration of the drug at the target point on the flow path of the liquid is equal to or higher than the target concentration. (1) When the reaction zone is a complete mixing type, and it is assumed that there is no consumption of the drug in the reaction zone, the drug is added at an arbitrary concentration A equal to or higher than the target concentration. A residual concentration calculating step of calculating a temporal change in the residual concentration of the drug at the target point, and (2) a residual for measuring a temporal change in the residual concentration of the drug at the target point when the drug is actually added at the concentration A. Concentration measurement step, and (3) residual concentration calculation at the time corresponding to the time when the residual concentration of the drug measured in the residual concentration measurement step has reached or is estimated to have reached the target concentration. Determine the residual concentration calculation value in degree, and a drug loading amount determining step of determining the amount of the drug on the basis of the calculated value. According to the method for controlling the amount of added drug according to the present invention, it is possible to reduce the time required to adjust the added amount of the drug to an appropriate amount.

FIG. 1 is a flowchart according to the control of the embodiment. FIG. 2 is a schematic diagram of the shale gas-accompanying water treatment system according to the embodiment. FIG. 3 is a schematic diagram of a reaction zone. FIG. 4 is a diagram showing the concentration transition of the inlet portion. FIG. 5 is a diagram showing the concentration transition of the outlet portion. FIG. 6 is an explanatory diagram of a method for determining a drug addition amount according to the embodiment.

  Hereinafter, a drug addition amount control method and a drug addition amount control apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited by this embodiment. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or those that are substantially the same.

[Embodiment]
The embodiment will be described with reference to FIGS. 1 to 6. The present embodiment relates to a drug addition amount control method and a drug addition amount control apparatus. FIG. 1 is a flowchart according to the control of the embodiment of the present invention, FIG. 2 is a schematic diagram of a shale gas associated water treatment system according to the embodiment, FIG. 3 is a schematic diagram of a reaction zone, and FIG. FIG. 5 is a diagram showing the concentration transition, FIG. 5 is a diagram showing the concentration transition of the outlet portion, and FIG. 6 is an explanatory diagram of the drug addition amount determining method of the embodiment.

  A shale gas-accompanying water treatment system 100 shown in FIG. 2 is a fracturing fluid treatment system that is press-fitted into a shale gas production well. In the production of shale gas, a fracturing fluid is injected from a well and the shale layer containing shale gas is crushed. Natural gas released from the shale layer is discharged through the well with the fracturing fluid. Natural gas is recovered from the fracturing fluid recovered from the well by gas-liquid separation.

  The shale gas associated water treatment system 100 includes a supply path 1, a drug injection port 2, a drug tank 3, a discharge path 4, a drug supply pipe 5, a drug supply amount control mechanism 6, and a residual concentration calculation means 10. The residual concentration measuring means 11 and the drug addition amount control means 12 are included. The supply path 1 is a distribution path that guides the fracturing fluid to the well 21. A drug injection port 2 is formed in the supply path 1. The drug injection port 2 communicates with the drug tank 3 through a drug supply pipe 5. The medicine tank 3 is a tank for storing medicine. In the present embodiment, glutaraldehyde is stored in the drug tank 3. Glutaraldehyde in the drug tank 3 is added to the fracturing fluid in the supply path 1 from the drug injection port 2 via the drug supply pipe 5. The medicine supply pipe 5 is provided with a medicine supply amount control mechanism 6. The medicine supply amount control mechanism 6 includes a flow rate control valve, a medicine supply pump, and the like.

  The fracturing fluid in the supply path 1 is pressed into the well 21 by a pump or the like, and the shale layer 22 is crushed. The shale gas discharged from the crushed shale layer 22 circulates in the well 21 together with the fracturing fluid, and is discharged through the discharge path 4. The discharge path 4 is a distribution path for discharging the fracturing fluid and shale gas in the well 21. The discharge path 4 is branched into a liquid discharge path 4A for discharging the fracturing fluid and a gas discharge path 4B for discharging a gas such as shale gas. The mixed fluid of the fracturing fluid and shale gas discharged from the well 21 is gas-liquid separated, and the fracturing fluid is sent to the liquid discharge passage 4A and the shale gas is sent to the gas discharge passage 4B.

  Agents such as bactericides and corrosion inhibitors are added to the fracturing fluid. In the shale gas-accompanying water treatment system 100 of this embodiment, glutaraldehyde is added to the fracturing fluid. It is desirable that the concentration of the drug in the fracturing fluid can be adjusted appropriately so that the drug can exert its effect moderately. For example, it is desirable that the residual concentration of the drug in the fracturing fluid flowing out from the well 21 can be controlled to the target concentration.

  When controlling the residual concentration of drug in the liquid flowing out of the reaction zone, it is conceivable to add the drug at the inlet of the reaction zone and detect the residual concentration at the outlet of the reaction zone to adjust the amount of drug added. . Conventionally, for example, the addition of a drug is started at the inlet of the reaction zone and the transition of the residual concentration at the outlet of the reaction zone is measured, and the drug is added based on the residual concentration when the residual concentration becomes steady. An addition amount control method for adjusting the amount has been performed. However, in this control method, there is a problem that it is necessary to wait until the residual concentration reaches a steady state, and it takes a long time to adjust the addition amount.

  In the drug addition amount control method according to the present embodiment, the addition amount of the drug added to the liquid at the inlet portion 20A of the reaction zone 20 through which the liquid flows is determined by the residual concentration of the drug at the target point on the liquid flow path. In this method, the concentration is controlled to be higher than the concentration.

  As described in detail below, the method for controlling the amount of added drug according to the present embodiment is as follows: (1) The drug in the reaction zone when the drug is added at a concentration A equal to or higher than the target concentration on the assumption that no drug is consumed. A residual concentration calculation step for calculating a change in residual concentration with time (unconsumed residual concentration Dc in FIG. 6); and (2) a change in residual concentration with time when a drug is actually added (residual concentration measurement value Dr in FIG. 6). ) And (3) a time point when the residual concentration of the drug measured in the residual concentration measurement step reaches or is estimated to have reached the target concentration (residual concentration target value Dt in FIG. 6) ( And a drug addition amount determination step for determining a drug addition amount (addition concentration command value Din in FIG. 6) based on time t1 in FIG. According to the drug addition amount control method according to the present embodiment, it is possible to shorten the time required to adjust the drug addition amount to an appropriate amount.

  Further, as shown in FIG. 2, the drug addition amount control apparatus 1-1 according to the present embodiment assumes that there is no consumption of the drug, and the reaction zone 20 when the drug is added at a concentration A equal to or higher than the target concentration. A residual concentration calculating means 10 for calculating a temporal change in the residual concentration of the drug in the blood; a residual concentration measuring means 11 for measuring a temporal change in the residual concentration when the drug is actually added (residual density measured value Dr in FIG. 6); The drug addition amount for controlling the drug addition amount based on the time (time t1 in FIG. 6) when the residual concentration of the drug measured by the residual concentration measuring means reaches the target concentration (residual concentration target value Dt in FIG. 6). And control means 12. According to the drug addition amount control apparatus 1-1 according to the present embodiment, it is possible to shorten the time required to adjust the drug addition amount to an appropriate amount.

  The drug addition amount control device 1-1 determines the addition amount of the drug to be added to the liquid at the inlet 20A of the reaction zone 20 through which the liquid flows, and the residual concentration of the drug at the target point on the liquid flow path is equal to or higher than the target concentration. It is the device which controls to become. The drug addition amount control device 1-1 includes a residual concentration calculation means 10, a residual concentration measurement means 11, and a drug addition amount control means 12.

  The reaction zone 20 of the present embodiment includes a supply path 1, a well 21, a shale layer 22, and a discharge path 4. The supply path 1 corresponds to the inlet portion 20A of the reaction zone 20, and the discharge path 4 corresponds to the outlet portion 20B of the reaction zone 20.

  The residual concentration measuring means 11 measures the chemical concentration of the fracturing fluid at the outlet 20B. The residual concentration measuring means 11 can measure the change over time in the residual concentration of the drug at the target point when the drug is actually added at the concentration A. The residual concentration measuring means 11 of the present embodiment is an absorptiometer and continuously measures the absorptiometry (E280) of the fracturing fluid at the outlet 20B. The absorptiometry measured by the residual concentration measuring means 11 is converted into the concentration of glutaraldehyde by the residual concentration calculating means 10, for example.

  The residual concentration calculation means 10 determines the value of the residual concentration of the drug at the target point and the elapsed time of the residual concentration when it is assumed that the reaction zone 20 is a complete mixing type and there is no drug consumption in the reaction zone 20. It has a function to calculate changes. More specifically, the residual concentration calculation means 10 calculates the value of the residual concentration at the target point and the change over time when the drug is added to the fracturing fluid at an arbitrary concentration A equal to or higher than the target concentration.

ここで、ｔは、薬剤注入開始からの経過時間、τは、入口部２０Ａから出口部２０Ｂまでの薬剤の滞留時間であり、下記式（１）で表される。
τ＝（反応ゾーン２０の体積）／（フラクチャリング流体の流量）…（１） FIG. 3 schematically shows the reaction zone 20. A fracturing fluid containing a medicine having a constant concentration Coin flows into the reaction zone 20 from the inlet 20A. From the state in which the reaction zone 20 is filled with the fracturing fluid not containing the medicine, the flow of the fracturing fluid containing the medicine having the constant concentration Coin starts at time t = 0. Assuming that the reaction zone 20 is a complete mixing type, an outflow concentration function F (t) indicating a change with time of the residual concentration of the drug at the outlet 20B is expressed by the following [Equation 1].

Here, t is the elapsed time from the start of drug injection, and τ is the residence time of the drug from the inlet 20A to the outlet 20B, and is expressed by the following formula (1).
τ = (volume of reaction zone 20) / (flow rate of fracturing fluid) (1)

  FIG. 4 is a diagram showing the transition of the drug concentration at the inlet portion 20A, and FIG. 5 is a diagram showing the transition of the drug concentration at the outlet portion 20B. As shown in FIG. 4, when the inflow of the fracturing fluid containing the medicine starts at time t = 0, the concentration detected at the inlet 20A changes at a constant concentration Coin. The unconsumed residual concentration Dc in FIG. 5 is the concentration calculated by the above [Equation 1], and is the concentration of the drug at the outlet 20B when it is assumed that the drug is not consumed by reaction with other components or heat. In practice, the chemical concentration of the fracturing fluid decreases due to reaction with pollutant components and heat. The residual concentration measurement value Dr shown in FIG. 5 is an example of the drug concentration at the outlet 20 </ b> B measured by the residual concentration measurement unit 11.

  The residual concentration measuring means 11 measures a change with time of the residual concentration of the drug at the target point when the drug is actually added at the concentration A. In this embodiment, the exit part 20B is a target point. The residual concentration measuring unit 11 measures the residual concentration at a predetermined interval and outputs a signal indicating the measurement result to the residual concentration calculating unit 10. The residual concentration calculation means 10 detects the time point when the residual concentration measured by the residual concentration measurement means 11 reaches or is estimated to have reached the target concentration at the outlet 20B. When the measured residual density matches the target density, the residual density calculation means 10 detects the time when the residual density is measured as the time when the target density is reached.

  Further, when the measured residual density exceeds the target density, the residual density calculation means 10 calculates a time point when it is estimated that the residual density has reached the target density. For example, the residual concentration calculation means 10 may estimate the time point when the residual concentration has reached the target concentration by interpolation, determine a function indicating the transition of the residual concentration from the measurement result of the residual concentration, and determine the residual concentration based on the function. It may be estimated when the density reaches the target density.

  The drug addition amount control means 12 is configured so that the residual concentration of the medicine measured by the residual concentration measurement means 11 at the time corresponding to the time when the drug reaches the target concentration or is estimated to have reached the target concentration. A calculated value is obtained, and the amount of drug added is controlled based on the calculated value. As will be described below, the drug addition amount control means 12 adds the concentration command value from the time when the residual concentration has reached or is estimated to have reached the target concentration (hereinafter simply referred to as “target reaching time t1”). Determine Din.

  In FIG. 6, the volume of the well 21 is 20,000 [m3], the flow rate of the fracturing fluid at the outlet 20B is 10,000 [m3 / day], the residual concentration target value Dt is 5 [mg / L], An example of the addition concentration command value Din determined under the condition that the concentration A is 10 [mg / L] is shown. The target reaching time point t1 is a time point at which the measured residual concentration reaches or is estimated to have reached the residual concentration target value Dt (5 [mg / L]). In FIG. 6, the residual concentration has reached the target concentration 1.4 days after the start of addition of glutaraldehyde and measurement of the residual concentration.

  According to FIG. 6, the value (8.6 [mg / L]) of the unconsumed residual concentration Dc at the time corresponding to the target arrival time t1 is the residual concentration calculation value by the residual concentration calculation means 10 at the corresponding time. is there. That is, if there is no consumption of glutaraldehyde in the reaction zone 20, it is estimated that the residual concentration of the drug at the outlet 20B after 1.4 days is 8.6 [mg / L]. From this, if 8.6 [mg / L] of glutaraldehyde is injected into the reaction zone 20 at the inlet 20A, it can be estimated that the concentration of glutaraldehyde at the outlet 20B becomes the target concentration of 5 [mg / L]. In the present embodiment, the residual concentration calculation value at the target arrival time t1 is set as the addition concentration command value Din. The medicine addition amount control means 12 controls the amount of medicine added to the fracturing fluid by the medicine supply amount control mechanism 6 so as to realize the addition concentration command value Din.

  The medicine addition amount control device 1-1 according to the present embodiment controls the amount of medicine addition based on the target arrival time t1. Accordingly, the amount of drug added can be adjusted at an earlier timing than the amount of drug added is adjusted after time t2 when it is confirmed that the measured residual concentration has reached a steady state. Therefore, the addition amount of the medicine can be quickly adjusted to an appropriate addition amount.

  With reference to FIG. 1, the chemical | medical agent addition amount control method which concerns on this embodiment is demonstrated. The control flow shown in FIG. 1 is executed when the amount of drug added to the fracturing fluid is adjusted. For example, the control flow may be executed when the press-fitting of the fracturing fluid is started, and at a predetermined interval. It may be executed, or may be executed based on the difference between the residual density measurement value Dr and the residual density target value Dt.

  First, in step S10, inflow of mine water into the pipe is started. The pump for pumping the fracturing fluid is driven, and the pumping of the fracturing fluid to the well 21 via the supply path 1 is started. The supply start and stop of the fracturing fluid and the control of the supply amount may be performed by, for example, a fluid supply amount control unit (not shown) or may be performed by the drug addition amount control unit 12. In the present embodiment, the fracturing fluid is pressed into the well 21 at a constant flow rate. When step S10 is executed, the process proceeds to step S20.

  In step S20, injection of glutaraldehyde is started at the inlet 20A by the drug addition amount control means 12. The medicine addition amount control means 12 instructs the medicine supply amount control mechanism 6 to inject glutaraldehyde into the fracturing fluid. The drug addition amount control means 12 outputs a command value for the drug addition amount to the drug supply amount control mechanism 6 so that the glutaraldehyde concentration in the fracturing fluid is a concentration A [mg / L].

  The concentration A is the initial concentration of the fluid that flows into the reaction zone 20 when determining the amount of glutaraldehyde to be added to the fracturing fluid, and can be an arbitrary concentration equal to or higher than the residual concentration target value Dt. In the present embodiment, the residual concentration target value Dt is 5 mg / L, whereas the concentration A is set to 10 mg / L. The density A may be determined by a magnification with respect to the residual density target value Dt, or may be determined by a difference with respect to the residual density target value Dt. For example, the concentration A may be determined as a concentration that is twice as high as the residual concentration target value Dt, and is a concentration that is larger than the residual concentration target value Dt by a predetermined concentration (for example, 5 [mg / L]). It may be determined. When step S20 is executed, the process proceeds to step S30.

  In step S30, the measurement of the absorbance at the outlet 20B by the residual concentration measuring means 11 is started. When the injection of glutaraldehyde is started by the drug addition amount control means 12, the residual concentration measurement means 11 starts measuring the absorbance of the fracturing fluid. The residual concentration measuring means 11 continuously performs the measurement of the absorbance (E280) and outputs a signal indicating the measurement result to the residual concentration calculating means 10. Step S30 corresponds to a residual concentration measurement step of measuring a change over time in the residual concentration of the drug at the target point when the drug is actually added at a concentration A. When step S30 is executed, the process proceeds to step S40.

  In step S40, the residual concentration calculation means 10 determines whether or not the residual concentration at the outlet 20B has reached the residual concentration target value Dt. If the residual concentration of glutaraldehyde converted from the absorbance measured by the residual concentration measuring means 11 is equal to or greater than the residual concentration target value Dt, an affirmative determination is made in step S40. As a result of the determination in step S40, when it is determined that the residual concentration of glutaraldehyde at the outlet 20B has reached the residual concentration target value Dt (step S40-Y), the process proceeds to step S50, and otherwise (step S40- In N), the determination in step S40 is repeated.

  In step S50, the target concentration time t1 and the like are calculated by the residual concentration calculation means 10. The residual concentration calculation means 10 calculates the time when the residual concentration of the outlet 20B reaches the residual concentration target value Dt. If the residual concentration of glutaraldehyde converted from the absorbance at the time of affirmative determination in step S40 is equal to the residual concentration target value Dt, the residual concentration reaches the residual concentration target value Dt when the absorbance is measured. It is said that it was time. On the other hand, if the residual concentration of glutaraldehyde converted from the absorbance at the time of affirmative determination in step S40 exceeds the residual concentration target value Dt, it remains at a time before the time when the absorbance is measured. It is estimated that the density has reached the residual density target value Dt. In this case, the time point at which the residual density is estimated to have reached the residual density target value Dt is determined based on the transition of the residual density measured so far.

  In addition, the residual concentration calculating means 10 assumes that the reaction zone 20 is a complete mixing type and that no drug is consumed in the reaction zone 20, and that the drug at the outlet 20B is added when the drug is added at a concentration A. The change with time of the residual concentration is calculated. That is, in this embodiment, a residual concentration calculation process is performed in step S50. The change over time in the residual concentration calculated by the residual concentration calculation means 10 is output to the drug addition amount control means 12. When step S50 is executed, the process proceeds to step S60.

  In step S60, the optimum injection concentration is determined by the drug addition amount control means 12. The drug addition amount control means 12 determines the residual concentration in the residual concentration calculation process at the time corresponding to the time when the residual concentration of the drug measured in step S40 has reached or is estimated to have reached the residual concentration target value Dt. Find the computed value. Referring to FIG. 6, the time point when the residual concentration measurement value Dr reaches or is estimated to have reached the residual concentration target value Dt is the target reaching time point t1. The value of the unconsumed residual concentration Dc at the time corresponding to the target reaching time t1 becomes the addition concentration command value Din. The drug addition amount control means 12 determines the drug addition amount based on the addition concentration command value Din. That is, in the present embodiment, in step S60, a drug addition amount determination step is executed.

The drug addition amount control means 12 adds the drug per unit time based on, for example, the flow rate Q [L / sec] of the fracturing fluid flowing through the supply path 1 and the addition concentration command value Din [mg / L]. The amount W [mg / sec] is determined by the following equation (2).
W = Din / Q (2)

  The medicine addition amount control means 12 controls the medicine supply amount control mechanism 6 so that the addition amount of the medicine injected from the medicine injection port 2 into the fracturing fluid is the determined addition amount W. When step S60 is executed, the control flow ends.

  According to the medicine addition amount control method according to the present embodiment, when the medicine is added at the concentration A, the medicine addition amount can be determined when the residual concentration of the medicine at the target point reaches the target concentration. Thereby, it is possible to determine an appropriate drug addition amount before the residual concentration of the drug becomes steady. Therefore, according to the drug addition amount control method of this embodiment, the time required to adjust the drug addition amount to an appropriate amount can be shortened.

  Further, according to the drug addition amount control apparatus 1-1 according to the present embodiment, when the drug is added at the concentration A, the drug addition amount is adjusted when the residual concentration of the drug at the target point reaches the target concentration. be able to. Thereby, it is possible to control the amount of the drug to be added before the residual concentration of the drug becomes steady. Therefore, according to the medicine addition amount control device 1-1 of the present embodiment, the time required for controlling the medicine addition amount for setting the residual concentration of the medicine to the residual concentration target value Dt can be shortened.

  An upper limit may be provided for the concentration A of the medicine when determining the addition concentration command value Din. For example, when an upper limit allowed for the residual concentration of the medicine in the liquid discharged from the outlet 20B is determined, it is desirable that the concentration A be equal to or lower than the upper limit concentration.

  The execution order of the residual concentration calculation step and the residual concentration measurement step is not limited to the example illustrated. In the present embodiment, the residual concentration measurement step (step S30) is executed prior to the residual concentration calculation step (step S50). Instead, the residual concentration calculation step is executed prior to the residual concentration measurement step. May be. Further, the residual concentration measuring step and the residual concentration calculating step may be executed in parallel.

[First Modification of Embodiment]
In the above embodiment, the residual concentration calculation means 10 calculates the change over time in the residual concentration of the drug at the target point, but instead of this, the residual concentration of the drug at the target point at any point in time is calculated. Also good. For example, the residual concentration calculation means 10 may calculate the residual concentration of the medicine at the target point at the target arrival time t1 when the target arrival time t1 is given.

[Second Modification of Embodiment]
In the above embodiment, the residual concentration measuring unit 11 measures the residual concentration of glutaraldehyde based on the absorbance of the fracturing fluid, but the method for measuring the residual concentration is not limited to this. The residual concentration measuring means 11 may measure the residual concentration of the drug by other methods.

  In the said embodiment, although the chemical | medical agent added was glutaraldehyde, it is not limited to this. Moreover, in the said embodiment, although the chemical | medical agent addition amount control method and the chemical | medical agent addition amount control apparatus 1-1 controlled the chemical | medical agent addition amount with respect to the fracturing fluid of the shale gas accompanying water processing system 100, it is not limited to this. The chemical addition amount control method and the chemical addition amount control apparatus 1-1 may control, for example, the addition amount of chemicals such as chlorine to clean water at a water purification plant, and the addition of chemicals such as chlorine to ballast water. The amount may be controlled.

[Third Modification of Embodiment]
In the method of the above embodiment (FIG. 1), there may be a case where the residual concentration of the medicine at the outlet 20B does not reach the residual concentration target value Dt. If the residual concentration of the outlet 20B to be measured does not reach the target concentration even when the residual concentration of the drug becomes steady, the addition of the drug to the fracturing fluid and the measurement of the residual concentration may be repeated from the beginning. In this case, the addition of the medicine is stopped and the press-fitting of the fracturing fluid is continued, and after the fracturing fluid in the reaction zone 20 is replaced with a fluid to which no medicine is added, the addition and the remaining of the medicine to the fracturing fluid are again performed. Start measuring the concentration. At this time, the concentration A of the medicine of the fracturing fluid that flows into the reaction zone 20 is higher than the previous concentration A. It is preferable that the increment of the density A is determined according to the difference between the residual density and the target density, which was the previous steady state.

  The contents disclosed in the above embodiments and modifications can be executed in appropriate combination.

1-1 Drug addition amount control device 1 Supply path 2 Drug injection port 3 Drug tank 4 Discharge path 5 Drug supply pipe 6 Drug supply amount control mechanism 10 Residual concentration calculation means 11 Residual concentration measurement means 12 Drug addition amount control means 20 Reaction zone 20A Inlet 20B Outlet 21 Well 22 Shale Formation 100 Shale Gas Water Treatment System Dc Unconsumed Residual Concentration Din Addition Concentration Command Value Dr Residual Concentration Measurement Value Dt Residual Concentration Target Value t1 Target Achievement Time

Claims (2)

  A method of controlling the amount of drug added to the liquid at the inlet of a reaction zone through which the liquid flows so that the residual concentration of the drug at a target point on the flow path of the liquid is equal to or higher than the target concentration. (1) When the reaction zone is a complete mixing type and it is assumed that the drug is not consumed in the reaction zone, the target when the drug is added at an arbitrary concentration A equal to or higher than the target concentration A residual concentration calculating step for calculating a temporal change in the residual concentration of the drug at the point; and (2) measuring a temporal change in the residual concentration of the drug at the target point when the drug is actually added at the concentration A. Corresponding to the time when the residual concentration of the drug measured in the residual concentration measuring step reaches or is estimated to have reached the target concentration. That at the time, determine the residual concentration calculation value at the residual concentration calculating step, the drug amount control method characterized by having a drug loading amount determining step of determining the amount of the drug on the basis of the calculated value.   An apparatus for controlling the amount of drug added to the liquid at the inlet of a reaction zone through which the liquid flows so that the residual concentration of the drug at a target point on the flow path of the liquid is equal to or higher than the target concentration. (1) When the reaction zone is a complete mixing type and it is assumed that the drug is not consumed in the reaction zone, the target when the drug is added at an arbitrary concentration A equal to or higher than the target concentration A residual concentration calculating means for calculating a temporal change in the residual concentration of the drug at the point; and (2) measuring a temporal change in the residual concentration of the drug at the target point when the drug is actually added at the concentration A. (3) corresponding to the time point when the residual concentration of the drug measured by the residual concentration measuring means has reached or is estimated to have reached the target concentration That at the time, determine the residual concentration calculation value by the residual concentration calculating means, the drug amount control apparatus characterized by having a drug loading amount control means for controlling the amount of the drug on the basis of the calculated value.

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