JPS59206741A - Method and apparatus for diluting mixed phase fluid of solid and gas - Google Patents

Abstract

PURPOSE:To measure the distribution of particle size and the concentration of particles highly accurately even if solid particles are in high temperature and high concentration and are fine particles by mixing dilution gas with solid/gas mixed fluid until the concentration of the number of solid particles, measuring temperature and the concentration of condensed components are reduced less than prescribed values to dilute the fluid. CONSTITUTION:The dilution gas is mixed with the solid/gas mixed fluid supplied by a sampling tube 2 to dilute the fluid and the diluted fluid is discharged from a discharge pipe 4. The dilution gas is supplied from feeding pipes 5, 5' to a dilution case 3 through flow meters 6 and regulating valves 7 and the solid/gas mixed fluid is diluted with the dilution gas by controlling the regulating valves 7 so that the concentration and temperature of the mixed gas are included in the measuring ranges of measuring devices, the concentration of condensed components contained in th mixed gas is less than the saturated concentration at the temperature and the concentration of the number of fine solid particles does not cause the reduction of the measuring accuracy by the reduction of the particles due to condensation and settlement.

Description

[Detailed description of the invention] To measure the particle number concentration and particle size distribution of relatively fine solid particles after coarse particles are removed from a solid-gas mixed-phase fluid of a blunt, which handles a solid-gas mixed-phase fluid such as a solid-gas mixed-phase fluid. The present invention relates to a method and apparatus for diluting a solid-gas mixed phase fluid.

The measurement of solid particles in such a solid-gas mixed phase fluid is
It is necessary to accurately understand the actual concentration and particle size distribution from the viewpoints of environmental preservation, research improvement, understanding equipment performance, and continuous status monitoring. In order to measure the particle number concentration and particle size distribution with high precision, it is necessary to introduce solid particles into the main stream of the solid-gas multiphase fluid by changing the measuring instrument without changing the state of the solid particles (changes in the concentration and particle size distribution). It is necessary to.

However, Brownian diffusion and collision, which are the inherent characteristics of particles, cause agglomeration between particles and deposition on solid-gas mixed phase fluid contact surfaces such as the inner wall of an inlet pipe, and these phenomena significantly reduce measurement accuracy.

In general, the above phenomenon tends to become more pronounced as the number concentration of solid particles increases and as the particles become finer. Special measures are required when measuring fine particles called airborne particles for the purpose of environmental measurement.

On the other hand, the general characteristics of measuring instruments that measure solid particles in solid-gas mixed-phase fluids are as follows: (1) In high-concentration solid-gas mixed-phase flows, measurement accuracy decreases significantly.

(2) The measurable sampling gas temperature is often close to the atmospheric temperature, so it is necessary to lower the sampling gas temperature.

(3) Moisture, sulfur trioxide (503) gas, etc. undergo a phase change from gas to liquid when the gas temperature is lowered by atmospheric temperature change. If such a so-called condensable substance is contained, if the sampling gas temperature is lowered by 11 degrees, the sample to be measured will aggregate using this condensable substance as a binder, and the particle size distribution and particle number concentration will change. bring about change.

There are problems such as.

The present invention solves these problems and uses a solid-gas multiphase fluid to enable highly accurate measurement of particle size distribution and particle number concentration even when the solid particles to be measured are high temperature, high concentration, and fine particles. This method provides a method for diluting an inert, low-humidity, and dust-free diluent gas into the sampling gas by adjusting the temperature and making sure that the concentration and temperature of the mixed gas are within the measurement range of the measurement instrument. The concentration of condensed components that can be contained in the mixed gas is less than the saturation concentration at that temperature, and the number concentration of fine solid particles does not decrease due to agglomeration and deposition of these particles, resulting in a decrease in measurement accuracy. It is diluted to a certain degree. As an embodiment of this method, the present invention includes a tubular mixing chamber with both ends closed, and a solid-gas mixed-phase fluid sampled at the center of one end of the mixing chamber in the axial direction. An inlet nozzle for discharging, a number of blowout pipes that are attached to one end of the mixing chamber and blowing out diluent gas obliquely with respect to the discharge direction of the solid-gas multiphase fluid, and one end of the mixing chamber on the outer periphery of the blowoff pipes. A large number of blow-off ports are provided to blow out dilution gas parallel to the axis,
Means for supplying an inert, low-humidity, and dust-free diluent gas to the blow-off pipe and the blow-out port by adjusting the temperature and flow rate, respectively, and a means for supplying an inert, low-humidity, and dust-free diluent gas to the blow-off pipe and the blow-out port, respectively, and a means for supplying the inert, low-humidity, and dust-free diluent gas to the blow-off pipe and the blow-off port, respectively, and a means for supplying the inert, low-humidity, and dust-free diluting gas to the blow-off pipe and the blow-off port, respectively; A diluting device for a solid-gas multiphase fluid is provided.

In other words, the present invention does not cause the above-mentioned problems by mixing a cleaned, dehumidified, inert, and temperature-controlled diluent gas into a solid-gas multiphase fluid sampled from the main flow of the solid-gas multiphase fluid for the purpose of measurement. Retention of a predetermined solid-gas multiphase fluid until the concentration of solid particles, measurement temperature, and condensed component concentration are below a predetermined number [interval, stirring capacity].

Since the dilution is carried out in a dilution container with a large capacity, part or all of the solid-gas multiphase fluid after dilution, whose solid particle number concentration, temperature, and condensed component concentration have been adjusted, is transferred from the dilution container at the solid particle number concentration. It will be possible to take a tour.

First, the principle of the dilution method of the present invention will be explained with reference to FIG.

Reference numeral 1 denotes the main flow of the solid-gas multiphase flow flowing inside the duct, a part of which is sampled by the sampling pipe 2.

3 is a dilution container that mixes the gas supplied through the sampling tube 2 with a dilution gas (described later) to dilute the gas, and discharges the diluted gas through the discharge tube 4. 5 and 5° are supply pipes for supplying dilution gas to the dilution container 3, which are connected to dilution gas tanks 8 and 8′ via a flow rate it 6 and a regulating valve 7, respectively. The dilution gas tanks 8 and 8' are for storing a low-humidity and dust-free inert gas, and are equipped with appropriate temperature control means so that the dilution gas can be set at an arbitrary temperature.

Therefore, by operating the regulating valve 7, the sampled gas and the dilution gas are mixed in the dilution container 3, and the temperature
It is possible to create a mixture of gases with a concentration. With this control, the concentration and temperature of the mixed gas are within the measurable range of the measuring instrument, the concentration of condensed components contained in the mixed gas is not saturated at that temperature, and it is fine. The number concentration of solid particles is diluted to such an extent that the measurement accuracy does not decrease due to aggregation and deposition of these particles. (Details will be described later) In addition, 9 is the measuring device 1 for the mixed gas mixed in the dilution container 3.
11 is a suction pump.

FIGS. 2 and 3 show a dilution container which is the central part of the apparatus of the present invention.

A mixing chamber 12 has a tubular shape with both ends closed, and an inlet nozzle 13 is installed at the center of one end 12A. This inlet nozzle 13 is connected to the sampling pipe 2 shown in FIG. 1, and discharges the sampled solid-gas mixed phase fluid in the axial direction within the mixing chamber 12. 1
Reference numeral 4 designates a large number of blow-off pipes disposed toward the end 12A side of the mixing chamber 12, which communicate with the dilution gas supply pipe 5, and blow out the dilution gas obliquely with respect to the discharge direction of the solid-gas mixed phase fluid. A blowout port 15 is provided at the end 12A of the mixing chamber 12 on the outer periphery of the blowoff pipe 14, and is connected to the dilution gas supply pipe 5' to blow out the dilution gas parallel to the axis. In addition,
These blow-off pipes 14 and blow-off ports 15 are arranged in a funnel-shaped neck (surface 1G) in the mixing chamber 12, and are formed between the slope 16, the inner wall of the mixing chamber 12, and the partition cylinder 17. Diluent gas is supplied and distributed to the chambers H, , H2, and a discharge port 17 opened at the end 12B of the mixing chamber 12 is connected to the discharge pipe 4.

Now, the flow rate and method of blowing out the diluent gas to be discharged from the blow-off pipe 14 and the blow-off port 15 are set so as to satisfy the following conditions, taking into consideration problems related to the inherent characteristics of the speech measuring device 10 and the solid particles.

(1) In order to prevent a decrease in the accuracy of the word measuring instrument 10 itself under a high concentration solid-gas mixed-phase fluid, dilute it with a predetermined (the most accurate measurement possible) solid-gas mixed-phase fluid main flow of the measuring instrument 10.

In other words, the combined flow rate Q+ of the dilution gas flow rate is determined using equation (1).

C1)+>Qs Ns/Nm
tl) However, Ql; Total flow rate of diluent gas is 81 (7/sec
) Qs: Sampling flow rate from the main stream of solid-gas mixed phase fluid (
(77 sec) (Flow rate of solid-gas mixed-phase fluid flowing in from the inlet nozzle 10) Ns: Approximate solid-gas mixed-phase fluid concentration (pieces/7) Nm: Upper limit solid-gas mixed-phase fluid concentration (pieces/Cd) (2) In order to prevent changes in concentration, particle size distribution, and morphology due to condensation of condensed components when cooling a high-temperature solid-gas mixed phase fluid to around atmospheric temperature 1, dilute it to a component concentration 1 that does not cause condensation even after cooling. However, if the solid-gas multiphase fluid flowing in from the inlet nozzle 13 is rapidly cooled, it may be locally cooled and condensed. Blows out dilution gas adjusted to a high temperature. Furthermore, in order to uniformly mix the solid-gas mixed phase fluid and the diluent gas within a short time, a blow-off pipe is installed.
The direction of the dilution gas blown out from the blow-off pipe 14 is adjusted so that the angle between the blow-out direction of the diluted gas blown out from the blow-off pipe 14 and the blow-out direction of the solid-gas multiphase fluid flowing in from the inlet nozzle 13 is 90' or less. The angle between the outlet direction and the tangent at the point of the inlet nozzle 13 closest to the blowout pipe 14 is 9.
Set the blowing angle of the blowing pipe 14 so that it is 0' or less,
A swirling flow was applied to the diluent gas. On the other hand, from the outlet 15 located outside the diluent gas blow-off pipe 14, dilute gas whose temperature is adjusted to the same level as the atmospheric temperature is blown out. The blowing direction of the blowing outlet 15 is parallel to the blowing direction of the solid-gas mixed phase fluid discharged from the inlet nozzle 13, so that the mixed gas of the solid-gas mixed phase fluid and the dilution gas discharged from the blowing pipe 14 is connected to the wall surface of the mixing chamber 12. A clean gas space is provided in between to prevent particles in the solid-gas mixed phase fluid from depositing on the wall surface of the mixing chamber 12 (generally referred to as adhesion, but in the case of solid particles, this expression is used for %). .

The method for blowing out the diluent gas has been described above, and the diluent gas flow rate Q2 necessary for preventing condensation in this section is determined by the +2j formula.

Q2 > QS CS/Co
(21 However, Q2 total flow rate of diluent gas (77se
c) Qs: Sampling flow rate from solid-gas multiphase fluid (7
7 sec) C5: Concentration of condensed components in the solid-gas mixed phase fluid to be sampled (VO1%) co = Saturation concentration of condensed components at the temperature of the solid-gas mixed phase fluid after mixing (vol) Co can be investigated in various documents, for example. Moisture often contained in combustion exhaust gas can be determined using a humidity chart. Note that the flow rate ratio and temperature of the diluent gas discharged from the blow-off pipe 14 and the blow-off port 15 depend on the temperature of the solid-gas mixed-phase fluid introduced from the inlet nozzle 13 and the properties of the solid-gas mixed-phase fluid, such as the concentration of condensed components. decide.

(3) Determine the amount of diluent gas to prevent solid particle agglomeration and deposition due to Brownian diffusion and collisions. Aggregation and deposition of particles can be determined as a theoretical solution using Fick's law. For example, changes in the number of particles due to aggregation and deposition can be calculated using formulas +31 and +41.

Immediately = 1+31 No KNoL'+1 Nt , ;, = Exp (-η) (4) However, No = particle number concentration in the initial state ([-0) (particles/cn) Nt: particle number concentration after i seconds ( pieces/, d) k: aggregation constant (cd/pieces' sec) t: elapsed time (sec) η: constant (dimensionless) In equation (3), if No on the right side becomes large, Nt/N on the left side
.

In equation (4), η on the right side tends to increase as NO increases, so as NO increases, NL/No decreases (due to agglomeration and deposition, the particle number concentration increases). (decreases).

Thereby, the diluent gas flow rate Q3 is determined by equation (5).

Q3':2 Qs Ns/N5
+51 However, Q3; Dilution gas flow fit (cn/s
ec ) Qs: Sampling flow rate from solid-gas multiphase fluid (
cn/5ec) N5: +31 and the solid-gas multiphase fluid concentration after dilution (Nt/No in formula (4) to the extent that it does not affect the test accuracy (number/, I+) or more tl+, +21 and (5) Set the dilution gas flow rate to satisfy the formula.

By the way, the approximate solid-gas mixed-phase fluid concentration Ns in equations (1) and (5) is the %li degree and particle size distribution of intermediate to paddy particles in the main stream of the fluid containing the solid-gas mixed-phase fluid, based on known standards such as JIS. Based on the measurement value of the measurement method (for example, "Measurement method of dust concentration in exhaust gas J etc." specified in JIS), or after removing intermediate or rice particles by inertial method such as cyclone, which is frequently used in the past, fine particles are determined. Only the fine particles are collected on a paper filter, and the concentration of the fine particles is determined in advance by the 31 measurement value of the 1 measurement method, etc., which determines the concentration of the fine particles based on the weight of the particles attached to the filter.

Regarding the density measurement method, in addition to the two examples described above, any measurement method suitable for the measurement of <4 in this J1 measurement may be used.

On the other hand, regarding the structure of the dilution valley device 3, (1) the blow-off pipe 14 and the blow-off port 15 that blow out the diluted gas are for mixing with the solid-gas mixed-phase fluid flowing in from the inlet nozzle 13; Part 12
A diluent gas having a predetermined temperature higher than the atmospheric temperature is blown out from around the inlet nozzle 13 attached at the center, and a diluent gas having a temperature similar to the atmospheric temperature is blown out from the outside. In addition, so that the solid-gas mixed phase fluid and the diluent gas are mixed uniformly within a short time (a), the angle between the blowing direction of the diluent gas blown out from the diluent gas blowing pipe 14 and the blowing direction of the solid-gas mixed phase fluid is 90° or less. The angle between the direction of the diluent gas blown out from the blow-off pipe 14 and the tangent at the nearest point of the inlet nozzle 13 is 9.
00 or less to generate a swirling flow in the diluent gas and uniformly mix it with the solid-gas mixed phase fluid within a short time. On the other hand, the blowing direction from the blowing outlet 15 is parallel to the blowing direction of the solid-gas mixed phase fluid. Note that the flow rate of the diluent gas is set to about 1 to 20 ml sec in consideration of miscibility, and the areas of the blow-off pipe i'4 and the blow-off port 15 are designed to achieve this flow rate.

(2) The inner diameter of the mixing chamber 12 is designed in consideration of the miscibility of the solid-gas multiphase fluid and the diluent gas flowing therein so as to create a turbulent flow state to the extent that no local concentration distribution of solid particles occurs.

(3) The length of the mixing chamber 12 is the residence time of the solid-gas mixed phase fluid after dilution, which is approximately proportional to the elapsed time in equation (3). Since NL/No becomes small as shown in FIG. 2, which may affect the silk measurement accuracy, design is performed by considering equation (3).

(4) The sampling pipe 9 that supplies the diluted solid-gas mixed phase fluid to the collecting device 10 is basically located at the rear, and the dimensions such as the inner diameter are determined to take into account agglomeration and deposition within the pipe (3) and (4)
It is best to design using the formula as a reference.

In addition, in order to prevent a decrease in measurement accuracy in the event that a positional concentration distribution of solid particles occurs within the mixing chamber 12, samples are taken at multiple points in the radial direction of the mixing chamber 12, and the flow velocity is set to be approximately equal to the gas flow velocity within the mixing chamber 12. Make it.

(5) The extraction port 17 for the solid-gas mixed phase fluid after dilution has a shape and dimensions of 7 so that no large pressure loss occurs in the same area.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram showing the principle of the present invention, FIG. 2 is a longitudinal cross-sectional view showing one embodiment of the diluter of the present invention, and FIG. 3 is a cross-sectional view taken along the line III-In in FIG. be. 1: solid-gas multiphase flow, 2: sample tube, 3: dilution container,
5.5゛: Supply pipe, 8.8°, dilution gas tank, 12:
Mixing chamber, 13: inlet nozzle, 14: blowout pipe, 15: blowout outlet. 1st ward

Claims (2)

[Claims] (1) A dilution method for measuring the concentration and particle size distribution of a sampled high-temperature, dense solid-gas multiphase fluid, in which the temperature of an inert, low-humidity, and dust-free diluent gas is added to the sampling gas. When adjusting and mixing, the concentration and temperature of the mixed gas are within the measurement range of the measuring instrument, the concentration of condensed components that can be contained in the mixed gas is less than the saturation concentration at that temperature, and fine solid particles are required. A dilution method in which the number concentration of particles is diluted to about 1A without reducing the measurement accuracy due to aggregation and deposition of particles. (2) A tubular mixing chamber with both ends closed, an inlet nozzle installed at the center of one end of the mixing chamber and discharging the sampled solid-gas mixed phase fluid in the axial direction, and one side of the mixing chamber. A mixing chamber is installed on the outer periphery of the blow-off pipe, and a dilution chamber is installed at one end of the blow-off pipe and runs parallel to the axis. A large number of blow-off ports for blowing out gas, a means for supplying inert, low-humidity, and dust-free dilution gas to these blow-off pipes and blow-off ports by adjusting the temperature and flow rate thereof, and the other end of the mixing chamber. or a discharge port opened in the body in the vicinity thereof.