JPS5823885B2 - Solid-gas multiphase fluid sampling device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sampling device for measuring solid particles in a solid-gas mixed-phase fluid in a plant that handles solid-gas mixed-phase fluid, such as a boiler, an incinerator, or a ceramic facility.

In order to measure solid particles in a solid-gas mixed phase fluid as described above, it is necessary to accurately grasp the actual concentration and particle size distribution from the viewpoints of environmental preservation, research improvement, understanding equipment performance, and continuous state monitoring.

In order to measure the concentration and particle size distribution with high precision, it is important to introduce the solid-gas mixed-phase fluid from the solid-gas mixed-phase fluid main stream to the measuring instrument without changing the state of the solid particles. One of the characteristics of particles is that particles coagulate due to Brownian motion and diffusion and are deposited on the inner wall of the introduction pipe, which greatly affects measurement accuracy.

In particular, the concentration in cement plants is 100,100 O't, and in the exhaust gas of coal-fired boilers it is 10 g/m', and under such high concentrations, the effects of the above-mentioned particle aggregation and deposition phenomena become significant.

Furthermore, as a measuring instrument that automatically and continuously measures solid particles in a solid-gas mixed phase fluid, (1) measurement is normally difficult under the high concentration conditions described above;

(11) Furthermore, since the measurable sampling gas temperature is often close to the atmospheric temperature, it is necessary to lower the sampling gas temperature.

(iii) Moisture, sulfur trioxide (S) in the sampling gas
Oa) When a gas is contained, if only the gas temperature is lowered, the solid particles will aggregate, causing a problem such as changes in particle size distribution and concentration.

Therefore, conventionally, as shown in FIG. 1, the solid-gas multiphase fluid flowing in the solid multiphase fluid main stream 01 is introduced into the dilution container 03 through the piping 02. Dilute with gas and measure this with 0
After adjusting the number concentration of solid particles according to the performance of the sample 6, the solid particles are introduced into a measuring device 06 through a pipe 05, and after measurement is completed in the measuring device 06, they are discharged out of the system by a suction pump 07.

However, such means have the following drawbacks.

That is, (1) when the solid particle number concentration is high, the pipe 02
Inside, the solid particle number concentration and particle size distribution change due to aggregation between particles and deposition on the inner wall of the pipe 02.

(2) In the dilution container 03, the cross-sectional area increases compared to the pipe 02, so the flow velocity decreases, and the degree of turbulence decreases accordingly.
The dilution gas introduced through the dilution gas is not mixed sufficiently, and the concentration (value multiplied by the dilution magnification) and particle size distribution of the diluted solid-gas mixed phase fluid sent to the measuring device 06 change.

(3) In order to reduce the influence of the above item (2), when mixing is performed by increasing the residence time of the solid-gas multiphase fluid in the dilution container 03, the capacity of the dilution container 03 increases.

In addition, aggregation of particles occurs due to Brownian motion in the dilution container 03, resulting in changes in the solid particle number concentration and particle size distribution.

The present invention was proposed in view of these circumstances, and it introduces a solid-gas multiphase fluid into a particle measuring instrument without preventing agglomeration or deposition and changing the state of the solid particle number concentration, 5 particle size distribution, etc. The purpose of this device is to provide a sampling device for solid-gas mixed-phase fluids, and the measurement device consists of multiple pores distributed in the longitudinal direction drilled into the peripheral wall, which sucks in solid-gas mixed-phase fluid from one end and communicates it to the other end. A diluent gas is introduced into the annular space between the solid-gas mixed-phase fluid sampling inner pipe that is supplied to the solid-gas mixed-phase fluid sampling inner pipe and the solid-gas mixed-phase fluid sampling inner pipe that is coaxially inserted into the solid-gas mixed-phase fluid sampling inner pipe. It is characterized in that it is a double pipe with an outer pipe for introducing diluent gas into the solid-gas multiphase fluid sampling inner pipe through the pores.

Embodiments of the present invention will be explained with reference to the drawings. FIG. 2 is an explanatory diagram showing the principle thereof, FIG. 3 is a partial vertical sectional view showing the first embodiment of the present device, and FIG. 5 is a partial vertical sectional view showing the second embodiment, 6 is a lateral sectional view taken along the line ■-■ in FIG. 5, and 7 is the length of the sampling tube. A diagram showing the solid particle number concentration distribution along the direction, Figure 8 is a diagram showing the relationship between the distribution concentration of the solid particle number and the reduction rate, and Figure 9 is a diagram showing the relationship between the length of the sampling tube and the reduction rate. FIG.

First, in FIGS. 2 to 4, reference numeral 8 denotes the main stream of the solid-gas mixed phase fluid flowing through the plant duct 8', 9 denotes a sampling pipe that sucks the solid-gas mixed phase fluid 9' from an open end located in the plant duct 8', and 9' 10 is a discharge pipe that branches downstream of the sampling pipe 9 and discharges a portion of the solid-gas mixed phase fluid after dilution, and 10 is a plurality of dilution gas trickles that introduce the dilution gas flowing in from the dilution gas pipe 10' into the sampling pipe 9. 11 is a measuring device for measuring solid particles in the diluted solid-gas mixed-phase fluid flowing in through the sampling pipe 9; 12 is a suction pump for introducing the solid-gas mixed-phase fluid into the measuring device 11; 13 is a diluting gas pipe 10; a pressure regulator for adjusting the pressure of the diluent gas fed into the
1 is a plurality of radial pores drilled at appropriate intervals p over the entire circumferential wall of the sampling inner tube 15 in the longitudinal direction;
7 is an annular square space between the sampling inner tube 15 and an outer tube 18 to be described later, 18 is an outer tube coaxially inserted into the sampling inner tube 15, and cooperates with the sampling inner tube 15 to form a double tube. , and both ends thereof are sealed with an annular wall around the outer periphery of the sampling inner tube 15.

In such an apparatus, the present invention will first be described in detail. As shown in FIG. sampling tube 9 through channel 10
The solid-gas mixed-phase fluid 9' flowing into the sampling tube 9 from the left end is maintained at a predetermined dilution ratio (solid-gas mixed-phase fluid flow rate /
dilution gas flow rate).

To this end, in the present invention, the sampling tube 9 and dilution gas tube 10' are formed as a double tube structure consisting of an inner tube 15 and an outer tube 18, as shown in FIGS. The dilution gas narrow flow path 100 function is performed by

The size and shape of the pores 16 and the number of pores 16 vary depending on the dilution ratio, the concentration of solid particles in the multiphase fluid, etc., but generally the diameter d
= 0.6 to 2.0 m +++ circular hole, the axial distance p is slightly different between the dilution zone and the holding zone described later, but it is p-5 to 20rrrrIL, and there are 6 to 10 holes on the same circumference.
Distributed at equal intervals.

However, as in the second embodiment shown in FIGS. 5 and 6, the pores 16 are inclined with respect to the sampling inner tube 15 so that the dilution gas flows in with a component in the flow direction of the multiphase fluid flowing in the sampling inner tube 15. Alternatively, as shown in Fig. 6, the holes may be formed obliquely in the circumferential direction to provide a joint flow to the diluent gas and to separate the solid-gas mixed phase fluid from the inner periphery of the sampling tube. It is also possible to form a thin film of diluent gas between the two.

The area of the pores 16 determines the dilution gas flow rate so that the relationship between the solid particle number concentration and the length direction of the sampling tube as shown in FIG. 7 is achieved.

In other words, in the upstream part of the sampling inner tube, that is, in the area where the number concentration of solid particles is high (hereinafter referred to as the dilution zone), the area of the pores 16 is increased to increase the flow rate of the dilution gas, and the number concentration of solid particles is rapidly reduced. Prevents particles from agglomerating and adhering to the inner wall of the sampling tube due to Brownian motion diffusion.

In the area where the number concentration of solid particles has decreased to such an extent that aggregation between particles due to Brownian motion and diffusion can be ignored (hereinafter referred to as the retention zone), dilution is applied to the inner wall of the sampling tube mainly to prevent deposition on the inner wall of the sampling tube. The area of the pores 16 is set such that the dilution gas flow rate is large enough to form a thin gas film.

Therefore, for the above-mentioned reason, the area of the pores 16 is made smaller sequentially from upstream to downstream of the solid-gas mixed phase fluid.

The pressure of the diluent gas is slightly higher than the pressure of the solid-gas multiphase fluid 9' (
Pressure regulator 13 so that the pressure is about several 100 MAq)
The flow rate of the diluent gas ejected from the pores 16 into the solid-gas mixed phase fluid 9' is adjusted to be approximately several m/s.

The dilution factor can be controlled by varying the number of pores 16 or the length of the dilution zone.

Brownian motion, aggregation of particles due to diffusion, and deposition on the inner wall of a pipe can be determined as theoretical solutions based on Fick's law.

For example, aggregation between particles can be calculated using equation (1), and deposition on the inner wall of a pipe can be calculated using equation (2).

No: particle number concentration in the initial state (particles/crrl'
) n: seconds after 〃, (pieces Zcrl)
k: constant (cnfA Bec)
L: Elapsed time (SeC)n
-η ・・・・・・・・・・・・(2)−−=
en.

Then, no: particle number concentration in the initial state (particles/-) n: after seconds (particles/cITl')〃 η: constant (-) From equations (1) and (2), Brownian motion, Figures 8 and 9 show the calculation results of the reduction rate for particles (particle size 0.1μ) that are considered to be largely influenced by diffusion.

When calculating, considering the various conditions of conventional measurement, the inner diameter of the pipe between the main flow of the solid-gas mixed phase fluid and the dilution container was set to 8.
m++z O The piping length between the main stream of the solid-gas mixed phase fluid and the dilution container is 57
H, 10yl.

0 Solid-gas mixed phase fluid flow rate 1i/m1n (20°C) Tojishima According to Fig. 8, the agglomeration between particles is, for example, when the solid particle number concentration is 107 particles/cni' (10 mg/m''), the reduction rate n/no is 91% for pipe lengths of 5 m and 10 m, respectively.
, 84% (in other words, the solid particle number concentration is 9 and 16%)
), and the particle size distribution also changes accordingly.

In addition, as shown in Figure 9, the deposition on the inner wall of the pipe is 5.
The reduction rate n/n□ at m and 10 m is 97% and 9, respectively.
5.5% (in other words, the solid particle number concentration is 3% and 4.5
% decrease), and the particle size distribution also changes accordingly.

Incidentally, this phenomenon occurs in piping 02. in Figure 1. This also occurs within the dilution container 03 and piping 05.

Finally, the results of measuring the particle number concentration of soot and dust in the test combustion furnace exhaust gas by the conventional measurement shown in FIG. 1 and the measurement using the present device shown in FIGS. 2 to 6 are shown.

In Fig. 1, the sampling gas amount is 51/min,
The inner diameter of pipe 05 is 4 mm, and the length is 10 m.

The dilution gas amount is 1000 l/min (dilution magnification 200
times).

The capacity of the suction pump is 1/min, and in FIG.
! rL, dilution gas pressure (positive) 500rrarLAq.

The diameter d of the pores is 1.5 rrm in the dilution zone, the axial spacing p is 10wrL2, 8 in the circumferential direction, and in the retention zone d = 0.7 mt p = 20 mm, 6 in the circumferential direction, total. When the dilution gas amount was set to 1000 / /min + the suction pump capacity was 1137 m1n, the solid particle number concentration was measured by both, and the result was 8 with the conventional method shown in Figure 1.
．． 2 x 106 (pcs AT!) 9.8 for 9 devices
X106 (pieces/cIT1') were obtained.

Difference between both measurement results (9.8X 106-8.2 Xl
06 = 16 x 106 pieces/cni') is due to agglomeration between particles or adhesion to the inner wall of the introduction pipe.In this way, the effect of this device was verified by actual measurements.

The above describes the sampling device of the present invention with the sampling inner tube 15.
Although an example has been described in which the present invention is applied to the dilution container 03, the present invention can also be applied to the dilution container 03 by enlarging the inner tube size.

When mixing solid-gas mixed phase fluid and diluting gas in a diluting container, the internal volume and structure of the diluting container 03 that can maintain a predetermined residence time necessary for mixing, the position of the pores that eject the diluting gas, The operating conditions such as the size, number, and dilution gas flow rate are determined in the same manner as for the sampling inner tube 15 illustrated and explained based on FIGS. 3 to 6.

In short, according to the present invention, a plurality of pores distributed in the longitudinal direction are bored in the peripheral wall, and a solid-gas mixed phase fluid is sucked in from one end and fed to a measuring device communicating with the other end. Dilution gas is introduced into the annular space between the fluid sampling inner tube and the solid-gas mixed-phase fluid sampling inner tube that is coaxially extrapolated to the solid-gas mixed-phase fluid sampling inner tube, and is introduced through the pores into the solid-gas mixed-phase fluid sampling inner tube. The present invention is industrially extremely useful because it provides a solid-gas mixed-phase fluid sampling device with high measurement accuracy by forming a double pipe with an outer pipe for feeding dilution gas into the solid-gas mixed-phase fluid sampling inner pipe. It is beneficial.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing a known sampling procedure for a solid-gas mixed phase fluid, Fig. 2 is an explanatory diagram showing the principle of the present invention, and Fig. 3 is a partial longitudinal sectional view showing a first embodiment of the present device. Figure 4 is the third
Fig. 5 is a partial vertical sectional view showing the second embodiment; Fig. 6 is a transverse sectional view taken along ■-■ in Fig. 5; Fig. 7 is a sampling A diagram showing the solid particle number concentration distribution along the length of the tube, Figure 8 is a diagram showing the relationship between the distribution concentration of the number of solid particles and the reduction rate, and Figure 9 shows the length of the sampling tube and the reduction rate. FIG. 8... Solid-gas mixed phase fluid main flow, 8'... Plant duct, 9... Sampling pipe, 9'...
...Solid-gas mixed phase fluid, 9'...Discharge pipe, 1
0... Dilution gas narrow channel, 10'... Dilution gas pipe, 11... Measuring instrument, 12... Suction pump, 13... Pressure adjustment. Vessel, 15...
Sampling inner tube, 16... Pore, 17...
... annular space, 18 ... outer tube.

Claims (1)

[Claims] 1. A solid-gas mixed-phase fluid sampling inner tube having a plurality of longitudinally distributed pores bored in the peripheral wall and sucking solid-gas mixed-phase fluid into one end and feeding it to a measuring device communicating with the other end; A diluent gas is coaxially extrapolated to the solid-gas mixed-phase fluid sampling inner tube and introduced into the annular space between the solid-gas mixed-phase fluid sampling inner tube, and is introduced into the solid-gas mixed-phase fluid sampling through the pores. A solid-gas mixed phase fluid sampling device characterized by comprising a double tube with an outer tube for diluting gas to be introduced into the tube.