JPH063392B2 - Flow velocity measurement method for high temperature powder - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for measuring the flow or flow velocity of a high temperature powder or granular material moving in a pipe in a non-fluidized state.

"Prior Art" A thermal delta response method is known as a method for measuring the downflow of a particle group (Chemical Engineering Proceedings Vol. 5, No. 2, page 155 (1979)). Regarding the moving speed, there are a method of using magnetic tracer particles, an optical method, a method of using piezoelectricity, etc. Furthermore, a target type of directly measuring the weight or detecting a load generated on a disk provided in the pipe line is used. There is also a flow meter.

[Problems to be solved by the invention]

The above-mentioned conventional technique can be easily applied to particles at room temperature or a relatively low temperature, but it becomes physically difficult at a high temperature, for example, 500 ° C. or higher.

Among them, the thermal delta response method is simple in principle and is an excessive method, but the method of the above-mentioned literature is to instantaneously heat a particle group by passing a pulse current through a heating wire such as a platinum wire, and It cannot be applied to particles of nature. Further, when the high temperature particles are further heated, the particles may be melted or sintered, and the durability is low.

The present invention mainly determines the movement or flow velocity of high-temperature powder particles flowing in a non-fluidized state in a transfer stand pipe (upright pipe) or an inclined pipe used for moving or circulating particles in a fluidized bed or a circulating fluidized bed. It provides a relatively simple method for detection.

[Means for Solving the Problems] The present invention supplies particles having a temperature lower than the particle flow in a pipe temporarily or in a pulsed manner from a small-diameter pipe protruding into an upright pipe or an inclined pipe, and downstream in the vicinity of the protruding pipe opening. This is a method to measure the time change of the thermal response by one or more temperature detection ends installed in the device to measure the flow or flow velocity of high temperature powder particles. Then
Since this is a method of measuring the particle flow, there is no problem such as melting or sintering of the particles as compared with the case where conventional high temperature particles are further heated, and there is no problem in durability.

In the present invention, the low-temperature particles are pulsed in the descending particles in the pipe by causing a small-diameter pipe opened in the downstream direction of the in-pipe particles to project into the upright pipe or the inclined pipe at an inclination greater than the repose angle or the static friction angle of the granular material. Can be put in. Therefore, since the low temperature particles that have entered in a pulse descend as a group, the temperature change can be detected extremely accurately at the temperature detecting end provided downstream in the vicinity of the small-diameter pipe opening. This allows the particle descent rate to be fully measured.

However, if the small-diameter tube does not protrude into the tube, it is possible that cold particles cannot be injected into the flow of hot particles in a pulsed manner. It could not be detected.

The range to which the present invention can be applied is Usl <(Umf / εmf) and ε <ε in the flow of high temperature powder.
Only when the relation of mf is established.

However, Usl = slip velocity Umf = minimum fluidization velocity εmf = minimum fluidization porosity ε = porosity at the time of measurement of the granular material, that is, when the high temperature granular material does not fluidize and is a moving bed of the piston flow Limited to

Further, the inclination angle of the small diameter tube projected into the tube through which the particles flow with respect to the horizontal plane must be at least for static friction between the particles and the small diameter tube or above the repose angle of the particles so that the flow of the low temperature particles is not stopped. This is generally 45 ° or more, preferably about 60 °. It is important that the tip projects in the downstream direction with respect to the flow of the hot particles, that is, the flow does not face the opening and is blocked so as not to face the opening. Therefore, it is preferable to bend the opening downward or to cut it obliquely downward.

〔Example〕

Embodiments of the present invention will be described with reference to the drawings. The circulation rate of high temperature particles was measured in a high temperature circulating fluidized bed as shown in FIG.

A high-temperature reaction gas (900 ° C.) was introduced into the fluidized bed 1 having an inner diameter of 38.4 mm from the fluidizing gas injection port 8 to form a turbulent fluidized bed. High temperature particles (sand iron powder of Umf = 2.2 cm / s) are sent from the fluidized bed to the settling chamber 2 by gas and separated from the gas, then the upright pipe (downcomer) 3 and the inclined pipe 5
Return to the bottom of the fluidized bed. There were few particles that could not be completely separated in the sedimentation chamber 2, but the cyclone 4
After being separated by, a small diameter tube 1 with an outer diameter of 34 mm and an inner diameter of 28 mm
It is returned to the upright pipe 3 through 1. The tubes 12 and 13 are gas inlets for controlling the circulation amount of particles. The apparatus is provided with a feed port 9 for feeding a sample and a withdrawal port 10 for withdrawing reactants.

High-temperature particles move in a vertical tube at about 880 ° C to form a moving layer, and a gas of Uf = 1.1cm / s flows upward in the surroundings, and a small-diameter tube 11 is inclined at an angle of 60 ° in the vertical tube. (Fig. 2), the low temperature particles (sand iron) at room temperature are supplied through the double valve 6 from the small-diameter pipe 11.
The cold particles fed at once are 100 g. Small diameter tube 1
Inserted at a distance of 125 mm directly under the opening of 1 3
The time change of the thermal response was measured by the thermocouple 7 of the book, and thereby the descending velocity of the hot particles was measured. The result is shown in FIG. 3 (solid line).

According to this, as a result of the thermal response, the downward velocity of the granular material is 1.7 cm /
s is measured, and the amount of circulating particles is 150 kg /
Calculated as m ² h. The broken line in FIG. 3 shows the case where the small-diameter pipe does not project from the pipe wall, and it is clear that the thermal response is broad and not suitable for measurement.

[Advantages of the Invention] The present invention, in a thermal response method for measuring the flow of a high temperature powder fluid in an upright pipe or an inclined pipe, has no problems such as sintering and melting, and does not include mechanical elements or consumable parts such as heating wires. Since it does not exist, it has great durability.

With such a simple structure, the circulation speed of the high-temperature powder or granules can be measured immediately and reliably, which is extremely effective in practice.

[Brief description of drawings]

FIG. 1 is a schematic view of a high-speed circulating fluidized bed apparatus according to an embodiment of the present invention, and FIG. 2 is an enlarged view of a main part of the apparatus shown in FIG.
FIG. 3 is a graph showing the thermal response results, where the solid line is the example of the present invention and the broken line is the comparative example in which the small-diameter pipe does not project. 1 ... Fluidized bed, 2 ... Sedimentation chamber 3 ... Upright pipe, 4 ... Cyclone 5 ... Inclined pipe, 6 ... Double valve 7 ... Temperature detection end (3) 8 ... Fluidizing gas inlet 9: Sample feed port, 10: Reactant withdrawal port 11: Projecting small-diameter tube 12: Circulation control gas injection port 13: Circulation assistance gas injection port

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Teruhiko Hirabayashi 1-17-25 Kasuya, Setagaya-ku, Tokyo (72) Inventor Kazuya Kunitomo 1618 Ida, Nakahara-ku, Kawasaki-shi, Kanagawa Nippon Steel Co., Ltd. Inside the laboratory (72) Inventor Yoichi Hayashi 1-1-1 Edamitsu, Yawatahigashi-ku, Kitakyushu, Fukuoka Prefecture

Claims (1)

[Claims] 1. A method for measuring the flow of high-temperature powder or granules in an upright pipe or an inclined pipe by using a thermal response method, comprising:
<(Umf / εmf) and ε <εmf, the particles having a temperature lower than that of the in-tube particle flow are temporarily or pulsed supplied from a small diameter tube protruding into the tube having an opening in the downstream direction of the particle flow. A method for measuring the flow or flow velocity of a high temperature powder fluid by detecting a temporal change in thermal response by means of one or a plurality of temperature detecting ends provided downstream of the opening. However, Usl = slip velocity Umf = minimum fluidization velocity εmf = minimum fluidization porosity ε = porosity at the time of measuring the granular material