SU1669730A1 - Method for making pellets from liquid composition - Google Patents

Abstract

This invention relates to a process for the production of granular foam. The purpose of the invention is the expansion of technological capabilities. To do this, the reaction mixture is sprayed in an upward gas flow, and the speed of the ascending gas flow along the path in the section of the reaction zone is slowed down according to the calculation formulas, ensuring the production of ultralight foamed and hardened foam granules of homogeneous structure. 1 il.

Description

This invention relates to a process for the preparation of granules from a liquid composition. It can be used in various branches of the national economy, for example, in chemical installation and special construction works, in particular, for the manufacture of thermal insulation of pipes.

The purpose of the invention is the expansion of technological capabilities.

The drawing shows a diagram of an apparatus for carrying out a method for producing granules from a liquid composition.

A device for producing granules includes sources 1 - 3 for supplying liquid components and compressed air, respectively, air mixer 4, reaction chamber 5, with inlet 5 and outlet 6, receiving hopper 8, gas source 9, sources 1 and 2 of liquid components connected to mixer 4 pipelines 10 and 11, and a source of 3 compressed air - duct

12, and a device for unloading granules

13, mounted at the outlet of the hopper 8.

In a method for producing granules from a liquid composition by spraying it in an ascending gas stream with decreasing flow.

the length of the reaction zone, the speed to expand technological capabilities, the reduction of the gas flow rate is carried out up to the soaring speed of the granules, which is determined by the formula V Vi + KI, in which

t

k-a .a v2-vi.

Vi + V2

L

VCp; 0 I L; cpiy2

 Vi + U2.tl / | about coftvdl ... poTte-dy 2- T.Vi -3..621,

where V is the gas flow rate in any section of the reaction zone;

I - the current coordinate of the path length of the gas stream in the reaction zone;

a is acceleration of slow motion of the gas stream;

VCp is the average gas flow rate is longer than the path;

L is the path length of the gas stream in the reaction zone;

T is the transit time of the path length by the gas flow;

Vi is the gas flow velocity in the inlet section of the reaction zone;

ABOUT

ABOUT

Yu

VI CJ

about

V2 is the gas flow velocity in the outlet section of the reaction zone;

yi is the volumetric weight of the mixture of liquid components;

y is the volumetric weight of the gas stream;

yi is the volume weight of the expanded granules;

di and d2 is the diameter of a drop of a mixture of liquid components at the entrance to the reaction chamber and the diameter of the finished granule, respectively;

Ci and C are the pressure drag coefficients of the droplet and the finished granule with diameters di and d2 when flowing around the gas stream.

The method is carried out as follows.

First, liquid components are prepared (heated to the required temperature, etc.) in the respective sources 1 and 2, including component tanks, heating elements, metering pumps or other blowers, pipelines, shut-off and regulating safety devices, and control valves and not shown). Then from sources 1 and 2 components through pipelines 10 and 11 in a predetermined ratio are supplied to the air mixer 4, which also receives compressed air from a source of compressed air 3 through duct 12. At the same time, through the inlet duct 14, a stream is fed into the reaction chamber 5 For example, air. In the air mixer 4, the liquid components are mixed in a predetermined ratio and a reaction liquid composition is obtained, which is sprayed into the ascending gas stream at inlet 6 into the reaction chamber 5. Here, the particles of the reaction mixture are concentrated throughout the inlet cross section of the internal channel of the reaction chamber 5. At the same time, at the inlet 6 to the reaction chamber 5, an upward flow velocity equal to the soar velocity of the particle of the reactive liquid composition, i.e. rdi

Vi 3.62

yCi

where Vi is the gas flow velocity in the inlet section (A-A) of the reaction zone;

yi is the volumetric weight of the mixture of liquid components;

y is the volumetric weight of the gas stream;

di is the diameter of a drop of the mixture of liquid components at the inlet 8 into the reaction chamber 5;

Ci is the pressure drag coefficient of a droplet with a diameter around it by a gas stream.

0

five

0

five

V2 3.62

As time progresses, particles of the reaction mixture increase in volume and float upward in the upward gas flow, reaching exit 7 from the reaction chamber 6. Through the exit cross section area (BB) of the internal channel of the reaction chamber 5, the reaction mixture passes in loosely foamed and cured finished granules, i.e. in the form of solid particles of foam, which are then transported by air to a receiving bin 8, from which they are discharged through a device 13 for unloading the finished granulated foam.

At the same time, at the outlet 7 of the reaction chamber 5, an upflow rate V2 is created equal to the soar velocity of the foamed and hardened foam granule, i.e.

d2,

uC2

where V2 is the gas flow velocity in the outlet section of the reaction zone;

Yi is the bulk density of the expanded granules;

d is the diameter of the finished granules,

y is the volumetric weight of the gas stream;

C2 is the coefficient of pressure resistance of the finished granule with a diameter of d2 when it is wrapped around a gas stream.

The length L of the gas flow path in the section of the reaction zone and the length of the internal channel of the reaction chamber 5, i.e. the distance between its inlet 6 and outlet 7, namely, 5 between the inlet cross section (A-A) and the outlet (BB) is taken to be

I V1 + V2 t L2I,

where L is the path length of the gas stream in the reaction zone, i.e. the length of the internal channel of the reaction chamber 5;

Vi is the gas flow velocity in the inlet section of the reaction zone;

T is the transit time of the path length L by the gas stream.

Example. Get the foam FRP-1 method, based on the metered mixing of liquid components - resin FRV-1A and the product VAG-3, for example, at a ratio of 1: 4, in the reaction mixture. It is necessary to reduce the consumption of components by reducing the volumetric weight of the foam, which is achieved by ensuring a comprehensive free foaming and solidification of the liquid composition during its conversion into foam, i.e. if you ensure the maximum rate of foaming.

0

five

0

five

0

To this end, the liquid composition is sprayed in an upward gas stream with a rate decreasing along the length of the reaction zone up to a soar rate of the granules, which is determined by the formula given above.

The fact that the decrease in the gas flow rate is carried out up to the soaring speed of the granules, which is determined by the proposed formula, makes it possible to obtain granules from the liquid composition by foaming and solidifying the particles of the reaction mixture in the gas flow, in which the particles are in a state of soaring, pops up as volume increases. At the same time, particles of foam from a liquid to a foam and hardened state of the finished granules, as it were, curl in a gaseous medium, i.e. foaming and curing of the reaction mixture occurs, as it were, in relative rest, not meeting obstacles in its path, since in this case the gas flow does not prevent foaming of foam particles. Foaming of the reaction mixture is complete, comprehensive, free. This provides the maximum rate of foaming of the reaction mixture and a decrease in the bulk weight of the foam, and thereby reducing the consumption of components, for example, resin FRV-1A and product VAG-3, when preparing granules from the FRP-1 foam plastic composition. In this sense, there is an expansion of the technological possibilities of the method of obtaining granules from a liquid composition.

Claims (1)

Invention Formula The method of obtaining granules from the liquid composition by spraying it in an ascending gas stream with a rate decreasing along the length of the reaction zone, about t0 liable for that. in order to expand technological capabilities, the gas flow rate is reduced to the soaring speed of the granules, which is determined by the formula V Vi + KI. wherein K - a  V2 -Vi a j , UtsM / 2 .. cf2, U S I S L, L Yl ± V2 .tag., where V is the gas flow rate in any section of the reaction zone; I is the current coordinate of the length of the gas flow path in the reaction zone; a is acceleration of slow motion of the gas stream; VCp. - average gas flow rate along the length of the path; L is the path length of the gas stream in the reaction zone; T is the transit time of the path length by the gas flow; . Vi is the gas flow velocity in the inlet section of the reaction zone; V2 is the gas flow velocity in the outlet section of the reaction zone; yi is the volumetric weight of the mixture of liquid components; y is the volumetric weight of the gas stream; YI is the volume weight of the expanded granules; di and - the diameter of a drop of the mixture of liquid components at the entrance to the reaction chamber and the diameter of the finished granule, respectively; Ci and C2 are the pressure drag coefficients of the droplet and the finished pellet with diameters di and d2 when flowing around the gas stream. 12