JPS6142212B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention addresses the problems that occur in conventional methods when measuring and diffracting the components of a target gas using a gas chromatograph or other analysis instrument, particularly the sample gas extraction point and sample gas pretreatment. This invention relates to an improved method that solves the troubles that occur between sampling racks and allows smooth and accurate measurement and analysis results to be obtained.

For example, during blast furnace operation, measurement and analysis of the components of blast furnace gas generated in the furnace can be used to determine the gas utilization rate, solution loss to understand the reduction state of ore, the amount of gas generated as an energy source, or It plays an extremely important role in considering pig iron production rates and setting and correcting operating guidelines based on these. Conventionally, in gas sampling for this purpose, a means as illustrated in FIG. 1 has generally been adopted, although there are some differences in type and content. That is, FIG. 1 shows the gas sampling means in a blast furnace, where A is a sampling gas take-off point, B is a sampling rack as a pretreatment engine for sampling gas, and C is a fractionator.
A part of the blast furnace gas generated in the blast furnace is continuously taken out by a sampling pipe 2 inserted at an appropriate point in the exhaust flow path 1 such as the dust catcher outlet, and then passed through a ball tank 3 to a probe 4 with a built-in filter. The dust is removed from the sample at the sampling rack B side via the switching valve 5, the measurement valve 6, and the drain pot 8 on the sampling rack B side. The device further removes dust, and the pressure reducing valve 11 reduces the gas pressure, for example, from the sampling gas pressure of about 1.5 Kg/cm ² at the extraction point A to about 0.2 Kg/cm ² , and the reduced pressure sample After the gas is completely dehumidified by the dehumidifier 12, it is introduced into, for example, an analyzer 13 in the spectrometer C, and in the analyzer 13, for example, H ₂ , N ₂ , Four components, CO and CO ₂ , are measured by spectroscopy, and these spectrometric component signals are input to a recorder 16 and a computer 17 via a processor 15 .
In particular, the computer 17 performs corrections, calibration curve corrections, etc. on this input, and employs it as various data. In sampling rack B in the figure,
17 is each flow meter in the primary filter 9 and dehumidifier 12, and 18 is a standard gas supply path, which is partly connected between the pressure reducing valve 11 and the dehumidifier 12 in order to prevent a delay from the flow meter. 19 indicates a pressure gauge, 20 indicates sample gases from the drain pot 8, 21 indicates the primary filter 9, and 22 indicates the sample gases from the dehumidifier 12. This is a discharge path for excess flow rate, and any excess sample gas is discharged through the vent pipe 23.
etc., and are released to the outside. Further, 24 is a supply path for purge gas (for example, N2 _, etc.) at the extraction point A, which is supplied to the switching valve 5 probe 4 via the purge valve 25 immediately before the sample gas is extracted.
This is for backwashing the sampling route of the sampling pipe 2.

A problem with such conventional sampling means is that troubles frequently occur particularly at the take-out point A and the sampling rack B. For example, at take-out point A, there are many problems such as poor replacement of purge gas after backwashing of the sampling route with purge gas at take-out point A, and leakage of purge gas and sample gas. Gas leakage can be prevented by improving the valve structure. However, it is difficult to prevent accidents caused by poor backwashing and replacement of purge gas, and analysis results may be distorted due to purge gas remaining in the sampling route. The problem becomes increasingly difficult to solve as the sample gas flow rate decreases due to the removal of dust, drain, etc., and furthermore, the exhaust volume decreases. In order to solve this problem, it is necessary to release a large amount of gas on the rack B side, and this means that because a large amount of sample gas is collected and released, dust and dirt are generated in each valve, piping, filters 9 and 10, and flow meter 17. A vicious cycle of problems occurs one after another, such as blockage accidents due to increased condensate, difficulty in long-term operation, difficulty maintaining a constant flow rate due to changes in discharge volume, and abnormal indications due to poor purge gas replacement. However, since the release of the sample gas from the exhaust channels 20, 21, and 22 in the sampling rack B occurs continuously during measurement and analysis, it is extremely difficult to solve this problem.

The present invention can easily solve the problems described above between the sample gas extraction point and the sampling rack by modifying the sample gas discharge means. , a part of the target gas such as blast furnace gas is continuously taken out from the outlet point of the discharge flow path as a sample gas for analysis and measurement during the analysis and measurement, and the sample gas is used as a purification means, a depressurization means and discharged. When the sample gas is quantitatively supplied to an analytical instrument such as a gas chromatograph for analysis measurement via a sampling rack equipped with a sampling rack, the sample gas is When the extraction of the sample gas starts, the sample gas is diffused for a predetermined period of time via a diffusion valve provided in the extraction flow path, and after the diffusion is completed, the sample gas is continuously fed to the sampling rack side via a measurement valve provided in the extraction flow path. The point is that we have made sure to send it to the target.

The present invention will be described in detail below based on the illustrated embodiments. FIG. 2 is a detailed view of the structure of the main part of the take-out point according to the conventional method, and FIG. 3 is a detailed view of the main part of the take-out point according to the method of the present invention. Figure 4 shows the time schedule of the valve's operation, Figure 5 shows the detailed structure of the main part of the drain pot, and Figure 6 shows the time schedule of the drain pot discharge valve and other valves.
In the figure, in the conventional method, a purge gas supply path 24 is connected to a purge valve 25-
1, 25-2, 25-3, and measurement valves 6-1, 6-2 are connected to the sampling rack B side.
A sample gas flow path 7 is communicated through the sample gas flow path 7.
Therefore, when backwashing the purge gas prior to sample gas collection, valves 25-1 and 25-2 are opened, valve 25-3 and valve 6-1 on the flow path 7 side are closed, and the supply path is A purge gas such as N ₂ is fed from 24 to the sampling pipe 2 side as shown by arrow P ₁ to backwash the sampling route. After that, when sampling the sample gas, the valves 25-1, 25-2 is closed, valves 6-1 and 6-2 on the flow path 7 side are opened, a part of the target rough gas is sampled from inside the flow path 1, and the sample gas is passed through the flow path 7. The sample is sent to the sampling rack B side as indicated by arrow _P2 , and measurement work begins here. At this time, there is a residual amount of purge gas ( _N2, etc.) in the sampling route from the sampling pipe 2 to the probe 4 immediately after the start of measurement, and the flow path 7
(sample gas transfer line) is quite long, so when pre-processing the sample gas in sampling rack B, an excessive amount of sample gas is sent than the intended amount and there is a time delay. Excess flow rate of sample gas including
As shown in the figure, the first stage of discharge at the drain pot 8, and the second stage of discharge at the first filter 9,
Like the third release in the dehumidifier 12, a large amount of gas is released. The movement of a large amount of rough gas containing dust and condensate tends to cause clogging in various equipment parts in the rack, such as valve piping, filters, flow meters, etc., and the effect increases with the passage of time. This causes a change in the amount of purge gas, making it difficult to maintain a constant flow rate, and ultimately leads to an abnormal indication due to insufficient replacement of the remaining purge gas. Therefore, it becomes necessary to inspect and maintain each part, and if an attempt is made to solve the problem by setting the discharge amount higher than the necessary amount, this will also lead to increased clogging of valves, pipes, etc. due to increased intrusion of dust and condensate. This results in a vicious cycle of various problems.

In the method of the present invention, by modifying this to the means illustrated in FIGS. 3 and 4, the extraction point A
This solves the trouble in sampling rack B, that is, in FIG. 3, purge valves 25-1, 25-2, and
-3 is installed in the same way as before, but the sample gas flow path 7 leading to sampling rack B is installed.
Of the conventional measuring valves 6-1 and 6-2, the front measuring valve 6-1 is an electric type, and the dissipation valve 6-1 is also an electric type. The valve 26 is newly installed via a branch path. That is, in the present invention, the sample gas dissipation valve 26 is provided at the sample gas extraction point A, and the purge valves 25-1 and 25 on the purge gas supply path 24 side are provided.
-2 and the measuring valve 6-1 and the discharging valve 27 are opened and closed in conjunction with each other according to a time schedule as shown in the fourth figure. In the figure, a and a' indicate the open and closed states of the purge valves 25-1 and 25-2, b and b' indicate the open and closed state of the emission valve 26, and c and c' indicate the measurement valve. 6-1 shows the opening and closing of the valve, but as shown in the schedule, first purge valve 2 is
Open 5-1 and 25-2 and put it on the sampling pipe 2 side.
Backwash the purge gas with N ₂ etc. and close the purge valve 25.
-1 and 25-2 are closed, and with the measurement valve 6-1 closed, the emission valve 26 is opened for the required time _T1 ,
Collect gas from gas flow path 1 Pipe 2 Probe 4
and dissipates into the outside world through T ₂ with the dissipation valve 26 closed.
After the time has elapsed, the measuring valve 6-1 is opened for the required time _T2 , and the sample gas is sent through the flow path 7 to the sampling rack B side as the measuring valve _6-2 is opened. 6-1 is closed, and after a delay of T ₃ hours, purge valves 25-1 and 25-2 are closed.
A series of valve operations are performed in which the valves are opened for purge gas backwashing, and the required time _T1 is approximately 0 to 10 seconds (an appropriate example is
10sec), T ₂ is about 0 to 6sec (appropriate example is
2sec), and _T3 is similarly set to about 0 to 6sec (3sec as a suitable example).

Installation of the release valve 26 and purge valve 25 as described above
According to the time schedule of the measurement valve 6, the sample gas collection of the present invention is performed as follows. That is, first, in backwashing the purge gas prior to sampling the sample gas, the purge valves 25-1 and 25-2 in the purge gas supply path 24 are opened and the purge valve 25-3 is closed, and the measurement valve in the sampling gas flow path 7 is closed. 6-1, 6-2 and the release valve 26 are closed, purge gas is supplied to the supply path 2.
4 through the probe 4 ball pot 3 sampling pipe 2 to perform backwashing, and at the end of the process, the purge valve 2
5-1 and 25-2 are closed, the purge valve 25-3 is opened, the measurement valves 6-1 and 6-2 are closed, and the diffusion valve 26 is opened, and the flow path 1 is The target gas is released from the release valve 26 to the outside for T ₁ hour. After this release, the release valve 26 is closed, and after a delay of T ₂ hours, the measurement valves 6-1 and 6 are opened.
- 2 is opened, and the sample gas is sent from the sampling pipe 2 side through the flow path 7 to the drain pot 8 of the sampling rack B.
The first filter 9 and the second filter 1
0 through dust removal and second stage gas release through the discharge channel 21 in the first filter 9.
It is sent to the pressure reducing valve 11, and after the predetermined pressure is reduced, it is sent to the dehumidifier 12.
As a result, a predetermined amount of sample gas is sent to the analyzer C side through complete dehumidification and third-stage gas discharge through the exhaust path 22, and a predetermined component analysis measurement is performed. At this time, it was confirmed that the gas discharge in the second stage through the discharge passage 21 could be significantly reduced from 6.6 to 2/min, and the gas discharge in the third stage through the discharge passage 22 could be significantly reduced from approximately 1.1 to 0.1/min. Also, the take-out point A
It was also confirmed that the purge gas was completely eliminated by the primary dispersion of the sampled gas by the dispersion valve 26 in the sampling process. It was also confirmed that measurement and analysis were possible on the rack B side even if the sample pressure decreased. In other words, in the conventional method, in the case of blast furnace gas, the sample pressure (furnace top gas pressure) is
When the sample pressure was below 0.5Kg/cm ² , it was impossible to replace the purge gas due to the limit of the amount released, making it difficult to measure.However, with the method of the present invention, the sample pressure
It was also confirmed that measurements up to 0.1Kg/cm ² were possible. In addition, in the operation according to the present invention, three of the purge valves 25-1, 25-2, and 25-3 are
At the end of backwashing, purge return 25-
The reason why purge return 25-2 is closed and purge return 25-3 is opened is as follows.

In other words, using three valves as purge valves means that
This is to prevent backwash purge gas _N2 from leaking into the measurement line side. Generally, in this type of measurement, the sample gas pressure is about 2.5Kg/cm ² , while the purge gas N ₂ pressure is high, about 5Kg/cm ² . 2
Even if it is closed, there is a risk of _N2 leaking into the measurement line, and furthermore, at the end of the purge, _N2 pressure is trapped between purge valve 25-1 and purge valve 25-2. Therefore, there is a risk that this confined N ₂ gas will leak into the measurement line from the purge valve 25-2 side. For this reason, the purge valves 25-1 and 25-2 are closed, and the purge valve 25-3 is opened to release the confined _N2 gas to the atmosphere and reduce it to zero.

According to the new installation of the diffusion valve 26 at the sample gas extraction point A according to the method of the present invention and the sample gas diffusion operation after the purge gas backwashing, gas release from the first stage sample gas discharge path 20 in the conventional drain pot 8 is reduced. This can be completely eliminated and the large amount of gas released during measurement in sampling rack B can be significantly reduced, but in this case, each pipe, valve, filter, etc. (However, except for drain pot 8), conventionally, steam trespassing is carried out to reduce the temperature to below the dew point at drain pot 8 and convert it into drain. However, in reality, condensate often enters the flow meter, etc. In the present invention, this steam tress is stopped in the flow path 7 before the sampling rack B, thereby increasing the amount of drain in the drain pot 8. At the same time, the discharge valve attached to the drain pot 8 is The aforementioned release valve 26
Measurement 1 at take-out point A, including the purge system, is used to centralize drains, facilitate and automate drain removal, discharge residual pressure gas in the rack, and improve responsiveness due to the distance from take-out point A. I did it like that. The embodiment is as shown in FIGS. 5 and 6. That is, as shown in FIG. 5, an electric discharge valve 27 is installed in the drain pot 8 together with a discharge passage 28, and as shown in FIG. Valve 26 Measuring valve 6-1
In combination with the time schedule of page valve 25-
1, 25-2, the discharge valve 27 is opened at the same time as the opening a of the purge gas reverse flow valve a, and the residual pressure gas remaining in the flow path 7 is not allowed to flow into the sampling rack B, but is drained from this drain pot. 8 is discharged from the bottom along with the drain to the outside world through a discharge passage 28. Next, after the primary gas is released by opening b of the release valve 26, a measurement valve _6- is used to introduce the sample gas for measurement with a delay of T2 hours. After opening 1, after a delay of T ₄ hours (T ₄ : 0 to 6 sec, 4 sec as a suitable example),
That is, in order to improve the long-distance response for _T4 seconds, the exhaust valve 27 is held open and the sample gas is introduced. In addition, as a preferable reference means for achieving other objects of the present invention, the structure of each valve at the extraction point A, especially the purge gas valve, is a conventional pneumatic three-way ball valve structure. Considering the size of the contact surface between the ball and the packing, it is preferable to use a two-way hole valve that allows for a larger contact surface.Also, the filter used for the probe 4 at the extraction point A is suitable for handling rough gas such as blast furnace gas. In this case, it is preferable to use a filter of about 20 microns rather than the conventional filter of about 70 microns
It is preferable that the stage filter 9 has a thickness of about 10 microns and the second stage filter 10 has a diameter of about 0.1 microns.
In addition, in the present invention, for the purging operation, the conventional continuous purge method during non-sampling is replaced with an intermittent purge method, and the size of the filter mesh in the probe 4 is reduced to 1/3 or less. , an intermittent purge method (intervals can be selected as appropriate) is preferable in terms of purge effect.

The gas sampling method according to the present invention is as described above, and includes the installation of a new diffusion valve 26 at the extraction point A and the primary diffusion of the collected sample gas at the extraction point in cooperation with the purge valve 25 and the measurement valve 6. The subsequent sample gas removal and transfer completely eliminates various troubles that conventionally occur from take-out point A to sampling rack B, that is, purge gas replacement failure accidents due to sample gas remaining in the purge gas, and eliminates purge gas replacement failure as the main cause. abnormality in the indication, sample gas release amount set higher than required amount, large amount of sample gas collected as a result, large amount of dust and condensate entering valves, piping, filters, and other equipment, and changes in the release amount. Vicious cycle problems such as difficulty in maintaining a constant flow rate can be resolved at the same time, making it possible to accurately and easily measure and analyze the necessary components. While the conventional method caused about 30 troubles in three months, the method of the present invention caused about 30 troubles under the same conditions.
The system has shown excellent results, with zero troubles occurring over the past few months, and can be said to have outstanding value as an improvement to gas sampling methods.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of an example of a conventional sampling means, Fig. 2 is an explanatory diagram of the main part of the extraction point of the conventional means, and Fig. 3 is an explanatory diagram of the main part of the extraction point of an embodiment of the sampling means according to the method of the present invention. , Fig. 4 is an explanatory diagram of the time schedule of the purge and measurement valve operating system, Fig. 5 is an explanatory diagram of the main parts of the drain pot, and Fig. 6 is an explanatory diagram of the interlocking time schedule of the pot discharge valve, purge, and measurement valve system. It is. A...Sample gas extraction point, B...Sampling rack, C...Analyzer, 25, 25-1, 2
5-2, 25-3...Purge valve, 6, 6-1, 6
-2...Measuring valve, 26...Diffusion valve, 27...Discharge valve, 2...Sampling pipe, 7...Sample gas flow path, 24...Purge gas supply path, 9, 10...Filter, 11... Pressure reducing valve, 12...Dehumidifier, 28
...Residual gas drain outlet.

Claims (1)

[Claims] 1. A part of the target gas such as blast furnace gas is continuously taken out as a sample gas for spectrometry from the outlet point of the discharge flow path during the spectrometry measurement, and the sample gas is passed through purification means and depressurization means. In addition, when the sample gas is quantitatively supplied to a spectrometer such as a gas chromatograph and subjected to spectrometry measurement via a sampling rack equipped with a discharge means, the sample gas is backwashed with purge gas at the sample gas take-out point. After that, when the sample gas starts to be taken out, the sample gas is diffused for a predetermined period of time through a diffusion valve provided in the extraction flow path, and after the diffusion is finished, the sample gas is released through a measurement valve provided in the extraction flow path. A gas sampling method characterized in that the gas is continuously fed to the sampling rack side.