JPS62175327A - Constant quantity exhausting method for pulverized/ granular substance - Google Patents

Abstract

PURPOSE:To provide constant quantity exhaustion of pulverized substance by holding steady the pressure in a constant quantity storing hopper, holding steady the level of the pulverized substance in the hopper, and allowing an agitating vane to make the substance density steady. CONSTITUTION:A control box 12 is installed, into which are fed a pressure signal for the upper space of a constant quantity exhaust machine 4 and a pressure signal for the upper space of a storing hopper, followed by comparison of these signals with the setting value stored in said control box 12, whereupon control is made so as to put the upper space pressure of said constant quantity exhaust machine 4 identical to the setting value. In this control, an atmospheric release valve 21 installed on a line 12a is opened when the upper space pressure of said storing hopper 1 is higher than the set pressure value for the upper space of the constant quantity exhaust machine 4. At the same time, a control is made so as to throttle a valve 22 for aeration air. If the pressure in the constant quantity exhaust machine 4 is higher than the upper space pressure of storing hopper 1, a valve 14 makes exhaustion to the upper space of storing hopper 1.

Description

Detailed Description of the Invention <Field of Application of Industrial Soil> The present invention relates to a method for quantitatively supplying powder and granular material into an air flow transport pipe from a powder and granular material quantitative discharge machine installed in an industrial plant or the like.

<Prior art and its problems> When dehydrated sludge is incinerated in a sludge incinerator, environmentally harmful substances such as sulfur oxides are usually generated in the combustion exhaust gas. Therefore, various methods are used to suppress these polluting harmful substances within certain standard values. There is a method to perform in-furnace desulfurization by supplying desulfurizing agent powder directly into the incinerator.In this case,
Depending on the properties of dehydrated sludge, the amount of SOx generated in combustion exhaust gas is 8.
It usually fluctuates over a range of about 00 to 2000 ppm, and in order to suppress SOx to a certain standard value, for example 20 ppm, it is necessary to supply the desulfurizing agent required for the reaction rate in a stepwise manner. . In this case, there is a means of supplying the desulfurizing agent powder using a powder quantitative discharge machine.

As a device for supplying powder to a fluidized bed in this way, heavy crude oil ash (main components are unburned carbon and ash) (referred to as IP ash) is used.
A device is known that supplies a fixed amount of water to a fluidized bed. (Utility Model Publication No. 60-26265) In FIG. 2, KP ash is usually supplied from a pipe line 8a to a hopper 2a by pneumatic transport, and the gas (air) used for transport is discharged via a dust collector 9a. The EP ash stored in the hopper 2a is sent to the quantitative storage hopper 2b via the rotary feeder 3a, and KP ash is further supplied from the rotary feeder 3b to the fluidized bed combustion furnace 1a.
The P ash is supplied to the ash supply pipe 4a. The supplied IP ash is supplied to the fluidized bed of the fluidized bed combustion furnace 1a by the transport gas from the blower 5a. Further, other fuels to be used are supplied to the fluidized bed combustion furnace from the auxiliary combustion fuel pump 7a, and after the operation becomes stable, the KP ash self-combusts. In this case, the rotary feeder (Figs. 3a and 3b) has a plurality of small chambers 14a formed by a plurality of blades 11a extending around the drive shaft 13a, and the weight of HP ash supplied and filled into these small chambers is constant. In some cases, if the rotational speed of the drive shaft is kept constant, the supply of EP ash becomes constant.

However, because this rotary feeder has blades that rotate within the casing 1Oa, the blade tips have a gap of θ1. It is necessary to have a gap e2 on the side surface. If this gap is too small, jamming will occur and the rotary feeder will be damaged. However, on the other hand, powder mixed with gas has water-like properties and leaks through minute gaps, reducing the precision of the rotary feeder's quantitative supply.On the other hand, a pressure difference is required between the inlet and outlet sides of the rotary feeder. In some cases, that equilibrium may be disrupted.

4a and 4b show an apparatus in which the relationship between the quantitative storage hopper 2b and the rotary feeder 3b in FIG. 2 is further improved.

The powder (explained below using desulfurization agent as an example) supplied to the storage hopper 1 is fed into a quantitative discharge machine 4 where the desulfurization agent is cut out (
When using a fixed volume between the blades of a rotary feeder, etc.), aeration air is supplied from the aeration pad 19 to the lower part of the storage hopper 1 in order to prevent blockage and keep the cutting in good condition. Normal 4
A sufficient aeration effect cannot be obtained unless there is a pressure of ~5 yen. At this time, the aeration air is the rotary pulp 2
Even if the double damper 3 is air-sealed with the groove structure in combination, not all of it can escape into the storage hopper 1.1, and some of it leaks into the hopper side of the metering discharger 4. As a result, the internal pressure in the upper space of the metering discharger 4 is The frequency is usually on the order of 600 to 800 mmHz, but it increases to 1 or close to 1. In addition, the air for transporting the desulfurizing agent powder may constantly leak from the bottom feeder 8 of the quantitative discharge machine 4, and the internal pressure of the quantitative discharge machine 4 may vary depending on the rotation speed of the feeder 8 and the height of the powder 1 inside the quantitative discharge machine. constantly changing.

The feeder 8 connected to the bottom of the metering discharger 4 is rotated by a drive motor 8b with its drive shaft vertical. This feeder 8 is like a rotary feeder with its axis vertical, and has a plurality of small chambers 8θ formed by a plurality of blades 8d, and powder is fed from a supply chute 8g or an opening 8f provided at the bottom of the metering discharger 4. supply shoe) 8c,
Alternatively, the powder is discharged into a transport pipe 10 that holds the parallel surfaces of the feeder body. Therefore, in the conventional quantitative dispensing machine, even if quantitative control is attempted using the small chamber 8C, which is a square with a constant volume, there is a problem in that it is not possible to obtain sufficiently effective quantitative performance due to the above-mentioned pressure fluctuations. .

To summarize these problems, it is necessary to satisfy the following conditions for quantitative feeding of powder using a rotary feeder.

(a) Constant speed rotation of the drive shaft (b) No change in the pressure difference between the rotary feeder intake side and outlet side (Q) Steady pressure in the quantitative storage hopper (i) Powder level in the quantitative storage hopper constant (θ) constant density of powder in the quantitative storage hopper (f) V;
e, steady state (Figures 3a and 3b) <Object of the invention> This invention solves (b) (C) (d) (e) among the above factors.
The aim is to propose a means of solving this problem.

Outline of Means for Keeping the Pressure in the Storage Hopper Constant The present invention provides
This is a method of discharging a fixed amount of powder by providing a stirring blade to keep the powder level in the hopper constant and the powder density constant.

<Example> Examples of the present invention will be described below with reference to FIG. 1, using desulfurizing agent powder as the powder. By detecting a low high level (hereinafter referred to as L level) of the desulfurizing agent powder layer of the metering discharger 4, aeration air is sent in and the desulfurizing agent powder stored in the storage hopper 15 raises the layer height level to a high level (hereinafter referred to as L level). (referred to as H level) is supplied to the fixed quantity discharger 4 until it is detected. The desulfurizing agent powder 15 supplied to the quantitative discharge machine number is supplied to the feeder 8 while being stirred by the stirring blade 7. The desulfurizing agent powder 15 supplied to the small chamber formed by the supply vane 6 of the feeder 8 has a sulfur oxide concentration (hereinafter referred to as S) at the chimney outlet.
If an attempt is made to suppress the oxygen content to within a certain standard value (referred to as the Ox value), for example, 20 ppm or less, the rotational speed of the supply blade electric motor 8 is changed by a corresponding amount to incinerate the air from the transport air blower 11. Pneumatically transported to a furnace (not shown). When the desulfurizing agent powder 15 is sent out from the storage hopper 1 to the quantitative discharge machine 4 and the rotary feeder 2, aeration air is sent from the aeration vat 19 to 4 to 5
~ is supplied to the lower part of the storage hopper 1. However, not all of the amount is discharged into the upper space of the storage hopper 1 into the atmosphere, but as explained earlier, the rotary feeder 2 and some portion have a double sealing device such as the sealing device 3. Even if the amount of liquid is exceeded, it leaks into the upper space of the hopper of the quantitative discharger 4, and the internal pressure of the hopper reaches 1 to nearly 1.

In such a state, the density of the powder supplied to the feeder 8 changes, and although a constant volume is supplied, a constant weight is not supplied, and the rotation speed of the motor 8a is changed in response to the change in density. It must be done.

In this embodiment, a control box 12 is provided, and a pressure signal in the upper space of the quantitative discharge machine number and a pressure signal in the northern space of the storage hopper are sent to this control box, and set values to be stored in the control box 12 and this signal are sent to the control box. The pressure in the upper space of the quantitative discharge machine 4 is controlled to the set value by comparing the numerical values.

The control is such that if the pressure in the upper space of the storage hopper 1 is higher than the set pressure value in the first part of the metering discharge machine 4, the pipe line 1
The atmosphere release valve 21 provided at 2a is opened. At the same time, control is performed to throttle the aeration air valve 22. Further, when the pressure within the quantitative discharge machine number is higher than the pressure within the hill space of the storage hopper 1, the valve 14 discharges to the upper space of the storage hopper 1. (Such a case may also occur depending on the conditions of the powder level in the storage hopper l.) <Example 2> In addition to the case of Example 1, the pressure upstream of the connection part of the feeder 8 of the powder transport pipe 10 The signal from the transmitting tube 23 is sent to the control box 20.
It is also possible to use the differential pressure between the upper space pressure of the metered discharge machine number and the upper space pressure as a control factor, increase the number of factors, and perform more careful metered supply control. 4 (Embodiment 3) The control described in Embodiment 1.2 can also be carried out by an operator manually operating each of the valves while looking at each of the pressure gauges.

Although FIG. 1 shows two feeders 8, it is possible to use a larger number of feeders, and to simultaneously send out powder through a plurality of tubes with one quantitative discharge machine.

<Effect of the invention> Control box 20. A pressure transmitter for the pressure in the upper space of the storage hopper,
By carrying out the present invention, which is equipped with a pressure transmitter for the pressure in the upper space of the quantitative feed machine, exhaust pipes 12.12a, and control valves for these pipes, the pressure in the first space of the quantitative discharge machine hopper can be reduced. Since the powder and granules supplied to the feeder 8 fill the small chamber at a constant rate, a constant amount of powder and granules are supplied from the feeder 8 to the granule transport pipe 10. As a result, the quantitative performance of the device was significantly improved.

, f10 simple description of the drawings. Figure 1 is a longitudinal cross-section of an apparatus and a pipe line showing an embodiment of the present invention. Figure 2 is an explanatory diagram of a conventional mass transporter. Figure 3a is a longitudinal cross-section of a rotary feeder. FIG. 3b is a cross-sectional view taken along the line A-A in FIG. 3a, FIG. 4a is a vertical cross-sectional view of a conventional quantitative transporter, and FIG. 4b is a perspective view schematically showing the feeder 8.

1...Storage hopper 2...Rotary feeder 3...Seal damper 4...
Quantitative discharge machine 5... Stirring blade 6...
- Supply vane 7...Agitator motor 8...Feeder 9...Transporting air short pipe 10...Powder transport pipe 11... ... Air transport fan 15 ... Desulfurizing agent powder 16 ... Bag filter - 17 ... Expansion joint 18 ... Sulfur oxide concentration transmitter No. Go to Figure 1. Figure 40.

Claims (1)

[Claims] 1. The signal of the pressure in the upper space of the metering discharger and the signal of the pressure in the upper space of the storage hopper are sent to a control box that stores and outputs command signals, and the two pressures are adjusted according to the commands of this control box. These 2
1. A method for quantitatively discharging powder and granular material, the method comprising controlling the opening and closing of a control valve provided in a pipe connecting two spaces and a control valve provided in an atmospheric discharge pipe to deliver a fixed amount of powder and granular material. 2. A signal of the internal pressure of the powder or granule transport pipe upstream from the connection portion between the powder or granule transport pipe and the feeder is sent to the control box for quantitative delivery of the powder or granule. The method for quantitatively discharging powder and granular material described.