SU582827A1 - Method of conducting processes in fountain-jet fluidised bed - Google Patents

Description

one

The invention relates to a technique for organizing processes in a gas-solid particle system and can be used in the chemical industry and related national households.

There is a known method for carrying out processes in a gas-solid system by supplying gas to a bed through gas distribution grid openings in a fluidized bed mode. operating devices, due to the small initial impulse of the jets, the length of the jet in the layer is small compared with the height of the layer. The ratio of the jet length to the layer height is of the order HF / Hp-O ,, Under these conditions, the outflow of gas jets from the gas distribution grid openings occurs in puzurkovo mode, characterized by the nucleation of bubbles above the grating hole, their growth and rise tl3

The coalescence of nucleated bubbles leads to the formation of gas inhomogeneities of a larger size in the immediate vicinity of the lattice and the further development of layer heterogeneity, which negatively affects the flow of a number of technological processes and reduces the interfacial intensity. interaction, increases the dynamic ablation of the layer, etc.

There is also known a method of carrying out processes in a jet-flowing layer, which includes feeding gas jets of length (0.6-1.1) to the layer through the holes of the gas distribution grid.

For the hydrodynamic state of this layer, the presence of two different forms of interfacial interaction of gas with particles is characteristic: the interaction in the jets and the interaction in the fluidized bed located between the jets.

A disadvantage of the known method is the low intensity of the transfer processes in the interjet zones of the layer, which is explained by the limited RADCusop of the intensifying effect of the jet in the layer, which is about half the jet length and significantly dependent on the physical properties of the particles, their size, surface state, etc. The close arrangement of the jets also reduces the intensity of the interfacial interaction due to the confluence of the jets and bubbles with the formation of large gas interlayers and even pistons. Ufe / ibfo iiiudpeic HMH is the intensity of the mass flow at the layer. The goal is achieved by the fact that the jet of the eider serves, subject to the juxtaposition of the spacing between the jets, to their l - 1 and g-t / l (0.3-0.5). The intensity of the skewing processes in the bed at the specified ratios; en lx step between the jets to their length is due to the introduction of the entire fluidizing agent into the bed under initial conditions. Ensuring the formation of powerful jets of comparable thickness with the height of the layer, the creation of an intensive circulation of particles through the jet and more intensive than in the fluidized bed, the movement of particles in the inter-jet zones. The drawing shows a device for carrying out the method. The device consists of an enclosure with a granular layer, equipped with a 1-distribution grid 2 sec from vertex 3 (round or rectangular shape). The method is carried out as follows. A granular bed is loaded into the apparatus and air is supplied under the gas distribution grid 2 to fluidize the bed. A fluidizing agent is introduced into the layer through the holes 3 and a layer comparable in length to the layer height is created in the layer. Under these conditions, a jet mode of gas outflow is realized, inducing an intensive circulation of particles through the jet. At a pitch between the jets equal to 0.3-0.5 of their length, the jets are carried, as well as the high intensity of the circulation of particles in the interjoint zone and a hydrodynamic state is created that is different from the classical fluidized bed and is characterized by organized high-intensity circulating particle movement, low pressure fluctuation in the bed, lack of dynamic entrainment and blister slip. The length of the jet is determined by the equation X - F - o, sbbschs / Where X is the length of the jet, mm; Example 1

Organized intensive circulation of particles throughout the entire height of the layer in the jet and interjet zones

The organized intensive circulation of particles over the entire height of the layer in the jet and interjet zones. The coalescence of outflowing jets, the formation of large gas bubbles in the upper part of the layer, the sharp oscillation of the surface of the layer and the intensive movement of particles in the sublattice zone I are the initial outflow velocity m / s; Cho - the initial radius of the hole, And - the speed of particle ejection, m / s; GI is the jet coefficient. Example 1. A cylindrical apparatus made of plexiglas with a diameter of 125 mm is provided with a replaceable perforated gas distribution grid with parameters: diameter of holes dg-l, mm, number of holes h -55, pitch between holes -15 mm. A spherical aluminosilicate catalyst layer of a fraction of 2-2.5 mm (particle soar speed -5.8 m / s, coefficient, 82), 92 mm high, is loaded into the apparatus, a fluidizing agent is fed in the amount of 0.0147 and a Hf-length jet is created in the layer -60mm at the value of the parameter t, 0.25. Through the transparent wall of the apparatus, the motion of the particles of the layer in the jets and interjet zones is observed. Example 2. The conditions of the experiment are similar to example 1, and the grill has the following parameters: the diameter of the do holes is 2.8 mm, the number of holes, the pitch between the holes is 20.2 mm, the length of the jet is 64 mm, and the parameter t / Xf 0 31 Example 3. The conditions of the experiment are similar to example 1, and the grill has the following parameters: the diameter of the holes is dp 6 mm, the number of holes 15, the pitch between the holes is 28.6 mm, the length of the stand is 61 mm, and the parameter i / Hf о, 4 7. Example 4, The test conditions are similar to example 1, and the grille has the following parameters: hole diameter dj, 1.5 mm, number, holes 5, the spacing between the holes i is 50 mm, the length of the jet is 92 mm, and parameter 1 / X -0.53. Example 5. The conditions of the experiment are similar to the example. 1, and the grating has the following parameters: the diameter of the holes is 14 mm, the number of holes and 5, ar between the holes is 50 mm, the length of the jet is 80 mm, and the parameter t / V ° b2. The results of observations on the state of the layer are as follows. Characteristics of the state of

Example

The organized intensive circulation of particles over the entire height of the layer in the jet zone and the reduced intensity of particle motion in the center of the interjet zones, the formation of stagnant zones between the holes in the grate, the dip of the particles through the holes

The organized intensive circulation of particles along the entire height of the layer in the jet zone with the formation of stagnant zones in the interjet zone, the failure of particles through the holes. Analysis of the results shows that the introduction of the entire fluidizing agent into the layer under initial conditions ensuring the formation of jets of length (0.6 -1.1) the height of the layer is optimal while observing the ratio of the pitch between the jets to their length 0.3-0.5. Under these conditions, the jetting state of the layer is formed with virtually no bubble breakthrough and with an intense particle circulation throughout the entire layer in the jet and interjet zones. When deviating from this ratio to the left, i.e. at O, 3, the jets merge with the formation of gas inhomogeneities in the upper part of the layer, resulting in a sharp pressure pulsation in the layer and the ejection of particles into the separation space. When deflected to the right, i.e. when i / HF 3-0.5, the intensity of movement

Table continuation

Claims (2)

The characterization of the state of the particle layer in the inter-jet zones is reduced down to the formation of stagnant zones. The method of carrying out the processes in the jet-spouting layer, including the flow of gas jets into the layer through the gas distribution grid with the ratio of the length of the jets to the height of the Hf / Hp layer (0.6-1.1), in order to intensify the heat exchange In the layer, the gas jets are supplied while observing the ratio of the step between the jets to their length (0.3-0, 5). Sources of information taken into account in the examination: 1. Minaez GA Dis.na a competitor. degree of candidate of science, MIHM, 1969. 2. Authors certificate of the USSR 298366, cl. B 01 J 8 / 18,19.10.67.