JP2004093372A - Online automatic gas chromatographic measurement apparatus for formalin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an automatic gas chromatographic measurement apparatus for formalin measurement capable of efficiently measuring online formalin-containing samples sampled from the sampling positions of a formalin reaction device and continuously fed via flow passage pipes. <P>SOLUTION: A gas chromatograph is provided with a sample select device having both a flow passage switching device for automatically taking the formalin-containing samples into the gas chromatograph and a device for flowing hot water into the flow passage pipes on the downstream side of the the flow passage switching device. The pipes are heated and washed by using the sample select device to prevent the deposition of the sample components from blocking the pipes and affecting the next measurement values. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
According to the present invention, a formalin-containing sample that is collected from each sampling point of a formalin reaction apparatus and continuously sent through each flow path pipe is automatically taken into a gas chromatograph using a flow path switching device. The present invention relates to an online automatic gas chromatograph for measuring formalin to be measured.
[0002]
[Prior art]
Conventionally, an on-line formalin gas chromatograph has been used in which a sample pipe is heated externally using an electric heater or the like to keep the temperature of the sample pipe. However, in such a method, if the piping is not sufficiently heated, blockage troubles such as precipitation of formalin multimers may occur. Was needed. In addition, since the formalin-containing samples sent from each sampling point are various with different concentrations of formalin and other components, the time required to remove the influence of the previous measurement must be taken each time measurement is performed. It is necessary to multiply and replace, and in many cases, replacement is insufficient, which has been a factor that hinders frequent measurement.
[0003]
[Problems to be solved by the invention]
An object of the present invention is to solve the above-mentioned problems in the prior art, and to provide a gas chromatograph that automatically analyzes a multi-channel online sample collected from each part of a formalin reactor.
[0004]
[Means for Solving the Problems]
The present inventor has conducted intensive studies on a gas chromatograph that automatically and accurately analyzes a formalin-containing sample collected from a formalin reactor on-line. As a result, the gas chromatograph has a flow path switching device to a sample injector 2. Hot water for heating and washing can be supplied to the piping and the sample injector 2 and a sample select device for performing the operation of flowing the hot water during the sample switching is provided. It has been found that, by flowing hot water, formalin concentration can be measured more efficiently with less precipitation trouble than when a conventional method of heating from outside the apparatus is used. In addition, by flowing hot water within the temperature range within the device, the piping from the sample select device to the sample injector and the injector can also be washed, so that the next measurement value due to insufficient replacement of the sampling flow path. The present inventors have found that the influence of the present invention can be eliminated, and reached the present invention.
[0005]
The present invention provides (1) a gas chromatograph 1, a sample injector 2 for injecting a formalin-containing sample into the gas chromatograph 1, and a continuous feed from each sampling point of a formalin reactor via each flow path pipe. The sample select device 3 having a channel switching device for automatically taking the formalin-containing sample into the gas chromatograph 1 and a device for flowing hot water into each channel pipe after the channel switching device, and controls each drive unit. A formalin on-line automatic gas chromatograph measuring device, which is composed of a program controller 4 and a measurement calculation control unit 5 so that the sample selection device 3 does not affect sample deposition and the next measurement value. In addition, the piping from the flow path switching device to the sample injector 2 and the sample injector 2 are heated. For cleaning can flow hot water, it is a device that operates to flow a hot water between the sample switching relates Automatic online gas chromatography measuring apparatus formalin according (1).
[0006]
BEST MODE FOR CARRYING OUT THE INVENTION
The present invention relates to an on-line automatic analyzer by a gas chromatography method used for monitoring a process of a formalin reactor. A multi-channel online sample that is continuously sent through a plurality of channels connected to each sampling point of the formalin device is subjected to gas chromatography through a sample selection device 3 that can switch sample channels and flow hot water inside. This is an automatic gas chromatograph which is introduced into a sample injector 2 for injecting into a chromatograph and is analyzed by a gas chromatograph.
[0007]
The concentration of formalin contained in formalin-containing samples to be analyzed online varies from high to low, so if the temperature of the sample itself drops, clogging problems due to precipitation of formalin multimers contained in the sample will increase. It is necessary to devise a method that does not lower the sample temperature. In addition, in order to accurately measure the formalin concentration in a sample mixed from a high concentration to a low concentration, if the replacement in the flow path piping is not sufficiently performed, the effect of the high concentration occurs and accurate analysis cannot be performed. The hot water is passed when the sample replacement is performed for each measurement in order to increase the effect of the sample replacement, so that the previous sample can be washed at the same time as the heating. As described above, the apparatus of the present invention is an automatic measurement system by a gas chromatography method which is suitably used as an on-line process monitor of a formalin reaction apparatus.
[0008]
【The invention's effect】
By using the apparatus and method of the present invention, it is possible to avoid clogging of the sampling pipe and interference with measured values due to residual components in the pipe, so that samples collected from each part of the formalin reactor are automatically and frequently used online and frequently. Measurement can be performed at a high response speed, which is very useful industrially.
[Brief description of the drawings]
FIG. 1 is a measurement apparatus of the present invention.
1: gas chromatograph 2: sample injector 3: sample selector 4: program controller 5: measurement operation control unit

Claims (2)

A gas chromatograph 1, a sample injector 2 for injecting a formalin-containing sample into the gas chromatograph 1, and a formalin-containing sample that is continuously sent from each sampling point of a formalin reactor via each flow path pipe are automatically generated. A sample select device 3 having a channel switching device for taking in the gas chromatograph 1 and a device for flowing hot water into each channel pipe after the channel switching device, a program controller 4 for controlling each drive unit, measurement calculation A formalin automatic gas chromatograph measuring apparatus characterized by comprising a control unit 5. Flowing hot water for heating and washing in the pipe from the flow path switching device to the sample injector 2 and the sample injector 2 so that the sample select device 3 does not affect sample deposition and the next measurement value. The formalin on-line automatic gas chromatograph measuring apparatus according to claim 1, wherein the apparatus performs an operation of flowing hot water during sample switching.

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