JPS58156360A - Removal of dust from sampled gas and apparatus therefor - Google Patents

Abstract

PURPOSE:To perform the continuous removal of dust from sampled gas over a long time, by withdrawing a part of introduced gas through the lower end of a cyclone dust catcher as the pretreatment of sampling for the analysis of flue gas. CONSTITUTION:A cyclone dust catcher 14 and a filter 15 are provided through a pump 16 at a conduit 13 for sampled gas extending from a flue 11 to an analyzer 12. P part of flue gas is introduced into the cyclone dust catcher 14, dust is removed from it therein, and gas at a ratio above 70% by volume of the introduced gas is withdrawn through the lower end of the dust catcher 14 and returned to the flue 11 through a conduit 18 equipped with a blower 17. Accordingly, the removal of dust from the sampled gas is continuously performed over a long period of time without the need to exchange the dust catcher.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a type of analysis of dust-laden flue gases.

Generally, in order to analyze flue gas containing dust, it is necessary to completely remove dust from the sampling gas. Therefore, conventionally, as shown in Figure 1, the flue (1
) to the analyzer (2) sampling gas conduit (3)
A primary filter (4) and a secondary filter (5) were installed via a pump (6), and dust removal was performed by these filters +41 to +51. However, in this method, when the dust concentration is high, the primary filter (4) becomes clogged in a short period of time, requiring frequent filter replacement.

This invention was made in view of the above points,
This was completed by improving the cyclone type dust collector to improve the dust removal efficiency and making it possible to use the device continuously for a long time.

The sampling gas dust removal method according to the present invention is characterized in that 70% or more of the incoming gas is extracted from the lower end of the cyclone type dust collector. The extracted gas is returned to the flue or dissipated into the atmosphere. The degassing rate is limited to 70% or more, as shown in Figure 4 below.
This is because if it is less than 0%, the dust removal effect will not be sufficient.

FIG. 2 shows an outline of the dust removal method according to the present invention. That is, a sampling gas conduit (131) leading from the flue (111 to the analyzer (121), a cyclone type dust collector (141) and a filter (151 downstream of this), and a pump (161)
Allocate via. A part of the flue gas is then guided to a cyclone type dust collector 041 for dust removal, and 70% or more of the inflow gas is removed from the lower end of the same device 141. A typical example is shown in Figure 3. This dust removal device is an improved version of the cyclone type dust collector, and includes a cylindrical portion having an inlet r211 on the side and an outlet at the top, and an inverted conical portion 24) provided at the lower end of the cylindrical portion. , a dust collection section □□□ provided at the lower end of this,
It consists of a gas vent (■) provided at the lower end of this.

The inlet @ has a cylindrical shape with a diameter less than half the diameter of the cylindrical part (2), and the dust collection part (c) is larger than the diameter of the cylindrical part (c)! It is small and has a cylindrical shape with a diameter larger than 175 mm. The sampling gas flowing in from the inlet flows downward while rotating in a spiral along the inner peripheral surfaces of the cylindrical part (C) and the inverted conical part (2), and reverses its flow near the lower end of the inverted conical part (2). As the dust rises, the dust is removed here. The dust separated from the airflow does not rise as the gas reverses, and is returned to the flue (21) by the gas extracted from the gas vent □□□.

Figure 4 shows the gas removal rate when the diameter of the outlet (■) is 0.3 times the diameter of the cylindrical part (c) and the diameter of the dust collecting part (2) is half the diameter of the cylindrical part (c). It is a graph showing the relationship between the dust removal rate of dust (fly ash).

As can be seen from the figure, the dust removal rate increases rapidly when the degassing rate is around 70%.

Since the present invention is constructed as described above, it is possible to continuously remove dust from the sampling gas for a long time without the need to replace the dust collector, and the dust removal rate can be greatly improved. Can be done.

[Brief explanation of the drawing]

FIG. 1 is a flowchart of a conventional dust removal method, and FIG. 2 is a graph showing seven stages of the dust removal method according to an embodiment of the present invention. 01)... Flue, 02... Analyzer, 0J0, Sampling gas conduit, ti41, Fist, Cyclone type dust collector, u81... Conduit, @ Fist... Gas outlet. Patent applicant: Hitachi Zosen Co., Ltd., Showa 5F [May 21, 1933] It l'1. ), 1-Special Issue of 1981, i'liK・11 No. 38663 2 Name of Ming Sampling Gas Dust Removal Method and Apparatus 3, Supplement 1: Each ITf'1. , relationship between γl applicant (11
“n 1-6-14 Edobori, Nishi-ku, Osaka City, Name (511) Hitachi Zosen Co., Ltd., 11th Director Address: 6-57, 1 x Unagidani Nishinocho, Osaka City
4 people outside the 6th floor of Nabe Building 5 Date of supplementary iT' order Showa year (1")
6. Number of inventions increased by Mn11 7 Supplementary IF χI VJ Detailed description of the invention in the specification column. Contents of the amendment (1) Change ``Gas,'' on page 4, line 13 of the specification to ``if the degassing rate is 70% or less.'' (2) Page 4, lines 16 to 5 Page 2, line 2, "airflow ~ never happens" [In this case, some of the ducts are entrained in the rising airflow again, so the separation efficiency is poor.On the other hand, the gas removal rate is 70
% or more, the flow no longer reverses, the collected dust is not re-splattered into the airflow, and the dust is corrected to ``. that's all

Claims (2)

[Claims] (1) 70 mm of gas flowing in from the bottom of the cyclone type dust collector
A sampling gas dust removal method characterized by extracting gas in an amount of % or more. (2) The method according to claim 1, in which the extracted gas is returned to the flue. A cyclone type dust collector comprising an inverted conical stage provided at the lower end and a dust collection section provided at the lower end, the sampling gas dust removing device comprising a gas vent provided at the lower end.