JPH01206256A - Method and apparatus for automatic titration of process fluid - Google Patents

Abstract

PURPOSE:To accurately foreknow the replenishing period of a reagent, by taking a definite amount of the reagent in a titration container and subsequently titrating the same by a process fluid to quantity the amount of the substance to be titrated in the process fluid. CONSTITUTION:A dry gas is introduced into a titration container 1 from a gas introducing pipe 7 to dry said container 1 and a predetermined amount of a Kar1 Fischer reagent is introduced into said container 1 from a reagent container 8 by a pump 9 while a predetermined amount of a titration solvent is introduced into the container 1 from a reagent container 1 by a pump 12. Subsequently, a process fluid is introduced into the container 1 from a process fluid source 15' through a pump 16 to advance titration reaction. The advance process of titration is traced by a final point detection mechanism 2 and the liquid feed amount of the pump 16 is adjusted corresponding to the detection signal thereof and, when titration reaches a final point, the moisture content of the process fluid is calculated from the amount of the process fluid used in titration by a calculation/control mechanism 20 to be displayed. Other valve 4 is opened to discharge the liquid in the container 1 to wash said container 1.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an automatic process fluid titration method and apparatus therefor. In particular, the present invention relates to a method for periodically titrating a process fluid using an automatic titrator.

<Prior Art> It is widely practiced to periodically titrate a fluid in a process using an automatic titration device. In the most common automatic titration method, a fixed amount of the fluid in the process is introduced into a titration vessel, a titration reagent is then added dropwise to the titration container, and the titration process is tracked by an endpoint detection mechanism to reach the endpoint. At this point, stop dropping the titration reagent, calculate the amount of titrant based on the amount of reagent consumed up to this point, drain the liquid in the titration container, and clean the container as necessary. The process of preparing for the next titration is automatically repeated.

<Problems to be Solved by the Invention> A problem with such an automatic titration method is that maintenance of the reagent container is troublesome. That is, since the amount of reagent required for each titration changes, it is necessary to check the reagent container from time to time and be careful to replenish the reagent at all times so as not to run out of reagent.

Means for Solving the Problems> The present invention measures the amount of a titrant in a process fluid by taking a certain amount of a reagent into a titration container and then titrating it with a process fluid.

That is, the present invention provides a method for automatically and repeatedly analyzing a process fluid extracted from a system in which the fluid exists by titration. According to this method, one analysis consists of (a) Reagent introduction process in which a fixed amount of reagent is supplied from a reagent container via a reagent quantitative supply mechanism (b) Titration in which the process fluid is supplied to the titration container in a controlled manner to cause the reagent in the titration container to react with the titrant. During the titration process, the reaction between the reagent and the titrant is tracked and the supply of process fluid is stopped when the end point of the reaction is reached.During the end point detection process, the liquid in the titration vessel is drained and the reagent is removed. It consists of each step of the post-treatment step to return to the state before supply, and the amount of the titrant is calculated from the amount of reagent and process fluid supplied to the titration container between the reagent introduction step and the titration step.

The present invention also provides a process analyzer that automatically and repeatedly analyzes a process fluid extracted from a system in which the fluid exists by titration, and this analyzer (a) tracks the titration process and determines the end point. (b) A reagent supply system comprising a reagent container and a conduit connecting the reagent container and the titration container and a reagent quantitative supply mechanism (c) Presence of process fluid (a process fluid supply system having a process fluid supply system comprising a conduit communicating the titration vessel with the titration vessel and a process fluid supply mechanism for supplying the process fluid to the titration vessel via the conduit in a controlled manner) A calculation mechanism that calculates the amount of the titrant in the process fluid based on the amount of process fluid supplied. The process fluid supply mechanism is equipped with a plunger type pump and a pulse motor that drives it, and the pulse motor is controlled by a signal from an end point detection mechanism. The pump is configured to discharge the entire amount of the sucked process fluid every seven operations.

One embodiment of the present invention will be described based on FIG.
1) is a titration container, (2) is an end point detection mechanism that electrically detects the titration end point, and (3) is an end point detection mechanism that also optically detects the titration end point. The end point detection mechanism may include either (2) or (3) depending on the type of process fluid and the titration reaction. (4) is a drain valve installed at the bottom of the titration container, and (5) is an automatic flow tube installed at the top of the titration container. It opens at a higher position. (6) is a stirrer, and (7) is a dry gas introduction pipe. (8) is a first reagent container, (9) is a first metering pump, and (9) is a first reagent conduit. (11), CI's,
αJ are the first reagent container, metering pump, and reagent conduit, respectively. Of course, depending on the type of titration, only one reagent container may be used. Further, the metering pump may be of any type as long as it can accurately deliver a predetermined amount of reagent. αyu is the process fluid source, such as a conduit through which the process fluid is flowing; α$, αe' and (1γ' are the conduits leading the process fluid from the process fluid source to the titration vessel (1);
αQ is a metering pump provided in the middle of this conduit, and α〃 and α〃' are valves for switching the process fluid source. The metering pump αQ must be capable of controlling and measuring the delivery amount to any desired amount with high precision; A plunger type pump is used.

In a preferred embodiment of the present invention, a pump with a discharge capacity smaller than the amount of process fluid considered necessary for seven titrations is used, and multiple titrations are performed during one titration. fc! Process fluid is drawn into the pump from a process fluid source. Particularly preferably, each actuation of the pump draws process fluid from a process fluid source;
And the entire amount is discharged into the titration container.

By doing so, the process fluid supplied to the titration vessel during the seven titrations can be close to the average value of the process fluid of the process fluid source during that period. As a result, even if a temporary or local change occurs in the process fluid source for some reason, it can be avoided from greatly affecting the measurement results. It goes without saying that the capacity of the conduits (1*, α9' and α→'' should be sufficiently smaller than the amount of process fluid considered necessary for seven titrations. 0→ is the volume of the standard solution. container, α
One is a valve for switching the suction end of pump αQ to this container α group. The standard solution is used to test the potency of the reagent, and is unnecessary if the reagent has good storage stability. 00 is a calculation/control mechanism that controls the operation of the entire device and calculates and displays titration results. Its main control functions are to sequentially operate the pumps and valves according to a predetermined time schedule, and Pump α responds to the signal indicating the progress of titration from the end point detection mechanism.
The purpose is to control the operation of Q so that the end point of titration can be accurately detected.

Effect> A case will be described in which, according to the present invention, a trace amount of water in an organic liquid in the petrochemical industry is titrated using a Karl-Fischer reagent.

First, after thoroughly cleaning the inside, drying gas was introduced from the gas introduction pipe (7) and the Karl Fischer reagent and reagent container α were added from the reagent container (8) to the titration container +11, which was thoroughly dried.
Pump the titration solvent from υ to each pump L9L 142
A predetermined amount is introduced after f. Then process fluid source 07
from the titration vessel [1
1 to proceed with the titration reaction. The progress of the titration is tracked by an end point detection mechanism (2), and the amount of liquid fed by the pump αQ is adjusted in accordance with the detection signal. As the end point detector, the mechanism (2), and the method of adjusting the amount of liquid pumped according to the detection signal, those used in a commercially available Karl Fischer volumetric titration device can be applied mutatis mutandis. When the titration reaches the end point, the calculation/control mechanism calculates and displays the moisture content of the instep from the amount of process fluid used in the titration. On the other hand, the valve (4) is opened to drain the liquid in the titration vessel (1), and then the valve (4) f is closed and the process fluid source (19'') is opened from which the process fluid to be titrated next time is drawn out. The process fluid is introduced into the titration container (1) by the pump OQ and flows out from the overflow pipe (5) to clean the inside of the container, and then the valve (4) is opened to drain the liquid.
Introduce drying gas to thoroughly dry the inside of the container in preparation for the next titration.

When testing the potency of Karl Fischer reagent,
The water-methanol standard solution in the standard solution container α barrel can be used instead of the process fluid for cleaning and titration of the titration container (1). This is for replacing the liquid in the conduit a5).

<Effects> According to the present invention, since the amount of reagent consumed in one titration is constant, the time to replenish the reagent can be accurately predicted according to the titration cycle. Furthermore, by extracting the process fluid from the fluid source multiple times and using it for the titration during the second titration, it is possible to reduce the influence of temporary or local fluctuations in the process fluid source.

Furthermore, the present invention is particularly advantageous when two or more reagents are used as a mixture on the spot, such as a Karl Fischer reagent and a titration solvent. This is because, according to the present invention, the titer of a reagent ready for titration after mixing can be assayed using a standard solution. If you want to titrate a certain amount of process fluid into a titration container9 with a reagent as in the conventional method, one or more reagents must be fed at a fixed ratio and while controlling the amount of liquid fed. A mechanism is required, and the machine and groove are more complicated than those required by the present invention.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of seven examples of apparatus for carrying out the present invention. Bar flow tube, 6
: Stirrer, 7: Dry gas introduction tube, g, ii: Reagent container,
wa, /2=reagent pump, 10. /,? : Reagent conduit,
/ILt=process fluid source, /S%/3',ls'':
Process fluid conduit, lA: Process fluid pump, 7
7′, /7”: Process fluid switching valve, 7g: Standard bath liquid container, /wo: Standard solution switching valve 1.2o: Calculation, control mechanism Patent applicant Mitsubishi Chemical Industries, Ltd. Representative Patent attorney For Hase - Others/Names

Claims (4)

[Claims] (1) A method in which a process fluid extracted from a system in which the fluid is present is automatically and repeatedly analyzed by titration, in which one analysis consists of (a) a reagent quantitative supply mechanism that supplies a fixed amount of reagent from a reagent container to a titration container; (b) A titration process in which the process fluid is supplied to the titration vessel in a controlled manner to cause the reagent in the titration vessel to react with the titrant. (c) The process of introducing the reagent and the titrant during the titration process. An end point detection process in which the reaction with the titrant is tracked and the supply of process fluid is stopped when the reaction end point is reached. (d) The liquid in the titration container is drained to return the container to the state before supplying the reagent. An automatic titration method comprising a post-treatment process and characterized in that the amount of the substance to be titrated is calculated from the amount of reagent supplied to the titration container and the amount of process fluid between the reagent introduction process and the titration process. (2) A method of automatically and repeatedly analyzing water in a process fluid extracted from a system in which the fluid exists, using a Karl Fischer reagent, in which one analysis is performed by (a) placing a titration vessel in a titration vessel; Reagent introduction process in which Karl Fischer reagent and Karl Fischer titration solvent are supplied in fixed amounts from each container (b) The process fluid is supplied to the titration container while controlling its amount, and the Karl Fischer titration in the titration container is Titration process of reacting with Fischer reagent (c) End point detection process of tracking the reaction between Karl Fischer reagent and water during the titration process and stopping the supply of process fluid when the reaction end point is reached (d) Titration vessel It consists of a post-treatment process in which the liquid in the titration vessel is drained to return the state to the state before supplying the Karl Fischer reagent, and the amount of reagent and process fluid supplied to the titration vessel between the reagent introduction process and the titration process are An automatic titration method characterized by calculating the amount of water in a process fluid. (3) The automatic titration method according to claim (1) or (2), characterized in that during the titration process, the process fluid is extracted from the system where the process fluid is present multiple times and supplied to the titration vessel. (4) An apparatus for automatically and repeatedly analyzing a process fluid extracted from a system in which the fluid exists, by titration, which includes (a) an end point detection mechanism for tracking the titration process and detecting the end point, and a solution discharge mechanism. (b) A reagent supply system comprising a reagent container and a conduit connecting the reagent container and the titration container and having a reagent quantitative supply mechanism (c) A conduit connecting the system in which the process fluid exists and the titration container. and having a process fluid supply mechanism for supplying the process fluid to the titration vessel via a conduit in a controlled manner. It consists of a calculation mechanism that calculates the amount of the titrant in the titration container (e) and a control mechanism that controls the operation of the entire device, including the supply and discharge of each fluid to the titration container, and the process fluid The supply mechanism is equipped with a plunger type pump and a pulse motor that drives the plunger type pump.The pulse motor is controlled by a signal from the end point detection mechanism, and the pump performs suction every time it is operated. 1. A device characterized in that the device is configured to discharge the entire amount of process fluid.