CS260585B1 - Fluid fluid supply device - Google Patents

Abstract

A device for supplying fluid to a fluidized bed equipped with floats that are connected to the core of an electromagnet, or the floats themselves form this core. By changing the current passing through the coil of the electromagnet, the magnitude of the force exerted by this coil on the float is changed, thereby adjusting the hydraulic resistance of the grate.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for supplying fluid to a fluidized bed having hydraulic resistance variable during operation.

From the research results described, for example, by Y. Shi et al. (AIChE J. 30, 860 (1984)) suggests that to achieve complete fluidization at a given linear fluid velocity, the ratio of the hydraulic resistance of the roll to the layer resistance must be equal to or exceed a certain minimum value. Since the resistance of the fluidized bed can vary significantly during operation, for example, by changing the granulometry or layer height and the hydraulic resistance of commonly used grates is a function of the linear velocity of the fluidizing fluid, changes in the grate / fluidized bed resistance ratio can occur. affect the quality of fluidization or increase the cost of introducing the fluid into the layer.

It therefore proves expedient to provide for a device allowing the continuous adjustment of the pressure drop of a fluid flowing at a constant linear velocity into the fluidized bed, i.e. to provide a grate with a hydraulic resistance adjustable during operation.

The essence of the device for supplying fluid to the fluidized bed on a plate with vertical tubes or with holes provided with floats according to the invention consists in that it consists of at least one float which is connected to or forms the core of the electromagnets. movably positioned in a magnetic field of an electromagnet coil which is connected to a control circuit.

The device according to the invention makes it possible to vary the hydraulic resistance of the grate independently of the air flow during operation.

The proposed solution consists in connecting the grate with the electromagnet core. The solenoid coil then applies a force to the float that is proportional to the current flowing through the coil. The advantage of this design is the possibility of easy connection of the control computer in a closed control loop.

The principle of solution is shown in Figures 1 and 2.

Giant. 1 illustratively shows the relationship between the quality of fluidization and the size ratios - ^and, where R. Is the hydraulic resistance of the grate, the resistance R _h of the fluidized bed, the linear velocity at ^r b "MF ^{α D.}

fluidization fluids and fluidization threshold rate. In the figure, three characteristic fluidized state regions are shown, B a layer channeling region, A a partial fluidization region, and a C complete fluidization region. The figure shows the control strategy as described in Example 1.

Figure 2 shows a possible constructional arrangement of the device described. The grate is formed by a horizontal plate 1, which pass through the vertical pipe 2 · d 2 ^e float rod 4 is connected with the stop 2 ^with magnet core 2 disposed movably in the coil 7 · The current flowing through coil 2 d ^e is determined by the control circuit 2 ·

Example 1

In a fluidized bed for combustion of coal, the fluid grate with a fluid inlet cap, part of which is shown in FIG. 2, is formed by a horizontal plate 2 through which the vertical tubes 2 pass. . The lower part of the float is connected by a rod 2 ^{to the} stop 5 with the electromagnet core 6 placed movably in the coil 2 · The current flowing through the coil 2 is determined by the control circuit 2 ·

During operation, the pressure drop across the layer varies due to changes in coal granulometry and layer height. The pressure drop across the layer is continuously measured and compared with the pressure drop of the grate. The control loop, whose action value is the grate hydraulic resistance, maintains a constant ratio of grate resistance to layer resistance in order to achieve complete fluidization at the lowest cost of air supply to the layer (see Figure 1).

Example 2

During the incineration of Example 1, some types of coal may develop incrustations which lead to clogging of the grate. The formation of these inhomogeneities can be continually indicated by measuring the dynamic pressure component of the layer as seen in Song et al. (Chem. Eng. Commun. 25, 105 (1984)). The control circuit 8 of the grate according to FIG. 2 is designed in such a way that it allows separate control of the hydraulic resistance of four equally sized sections. In case of indication of the formation of incrustations in the respective section, its hydraulic resistance is set to a minimum, whereby the incrustations are torn off by significantly increasing the flow of fluidizing fluid in said section.

Claims (1)

object of the invention Apparatus for supplying fluid to a fluidized bed mounted on a plate with vertical tubes or with holes provided with floats, characterized in that it consists of at least one float (3) which is connected to or forms the core (6) of the electromagnet, the core of the electromagnet (6) is movably positioned in the magnetic field of the coil of the electromagnet (7), which is connected to the control circuit (8).