RU2362102C1 - Drier with active hydrodynamic operating conditions - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to drying techniques, particularly to devices that serve to carry out heat-and-mass transfer in dispersed products and can be used in food, chemical and like industrial branches. The proposed drier comprises cylindrical conical-bottom drying chamber with cover and opening to offtake waste heat carrier and dried product. Aforesaid opening represents a rectangular cutout made in the drying chamber top and accommodating tangential heat-carrier feed branch pipes and that to feed heat carrier axially in case the drier emergently stops. It incorporates also a screen to hold the product in the former case. The tangential heat-carrier feed branch pipes are arranged, opposite one another, at the upper part of heat carrier axial feed branch pipe at 90° and in symmetry with the drier axis. The said branch pipes are arranged to allow varying the angle to the drier axis both horizontally and vertically. Aforesaid screen is fitted at the heat carrier axial feed branch pipe lower part. The latter branch pipe doubles for gas mixer device. To this end, it incorporates starting product feeder arranged above previously mentioned screen and starting product acceleration section.

EFFECT: increased quality of finished product, intensified heat-and-mass transfer.

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Description

The invention relates to a drying technique, in particular to devices for carrying out heat and mass transfer processes, namely, drying of dispersed products, and can be used in food, chemical and related industries.

One of the main directions of intensification of heat and mass transfer processes is the improvement of the hydrodynamic situation in the apparatus. Drying methods based on the technology of the suspended layer, are currently becoming increasingly common in industry.

The closest to the proposed technical essence and the achieved result is a dryer with active hydrodynamics and fractional processing of material, containing a drying chamber with a pipe for inputting the initial product, divided into cylindrical sections, in the upper part of which are installed cylinder-conical inserts located along the chamber axis and separating it into zones, with tangentially installed nozzles for supplying an additional coolant flow and a nozzle for supplying the main coolant flow I, made along the axis of the chamber in its lower part, a grill designed to prevent particles of the product from entering the air duct, a cover that includes nozzles for discharging waste heat carrier. The drying chamber consists of a chamber for unloading a dry product, cylindrical sections, in the upper part of which there are windows for outputting the product and waste heat carrier, which are annular slots, the geometry and quantity of which depends on the hydrodynamic properties and particle sizes of the processed product [Patent No. 2272230, publ. . March 20, 2006, F26B 17/10].

The known design has several significant disadvantages:

- low intensity of heat and mass transfer processes;

- low quality of the finished product, as possible entrainment of the product coming to the drying along with the dried product;

- insufficient uniformity of swirling of the product and coolant flow, since the tangential coolant flow is supplied with one pipe to each section;

- the impossibility of regulating the hydrodynamic situation in the drying chamber.

An object of the invention is to improve the quality of the finished product, the intensification of heat and mass transfer and the regulation of the hydrodynamic situation in the drying chamber.

The object of the invention is achieved by the fact that in a dryer with an active hydrodynamic regime, containing a cylindrical drying chamber with a conical bottom, a lid and a window for discharging waste heat carrier and dried product, made in the form of a rectangular cutout in the upper part of the drying chamber, with tangentially mounted nozzles for supply of the tangential flow of coolant and a pipe for supplying an axial flow of coolant, made along the axis of the chamber in its lower part, a grill for neighing of the product in case the dryer stops, the new fact is that the nozzles for supplying the tangential flow of coolant are installed in the upper part of the nozzle for supplying the axial flow of the coolant at an angle of 90 ° symmetrically to the axis of the dryer, one against the other, and made with the possibility of changing the angle relative to the axis of the dryer in horizontal and vertical directions, the grill is located in the lower part of the nozzle for supplying the axial flow of coolant, and the nozzle for supplying the axial flow of coolant nyaet function device receiving gas suspension, which is provided with a feeder starting material, arranged above the lattice to contain the product, and has a speeding-up section for initial product.

The technical result consists in improving the quality of the finished product, the intensification of heat and mass transfer processes and the regulation of the hydrodynamic situation in the drying chamber.

The drawing shows the proposed dryer.

The dryer consists of a drying chamber 1 with a window 2 for the exit of the mixture of the dried product and the spent coolant, a conical bottom 3 and a cover 4, a pipe 5 for supplying an axial flow of the coolant, in which a feeder 6 is installed for supplying the initial product and two pipes 7 for supplying tangential coolant flows installed in the upper part of the nozzle 5 for supplying an axial coolant flow at an angle of 90 ° symmetrically to the axis of the dryer, one against the other, and made with the possibility of changing the angle relative to the axis of the su ilki in horizontal and vertical directions. The grill 8, designed to hold the product in case the dryer stops, is located below the feeder 6. The pipe 5 has an accelerating section.

The trajectories of the swirling coolant flows formed by the supply of tangential flows are shown by lines 9, the trajectories of the dried product are shown by lines 10.

The dryer operates as follows.

The initial product is fed by a feeder 6 to a pipe for supplying an axial flow of heat carrier 5, where it is carried away by an axial flow of heat carrier, accelerates in the accelerating section and forms a gas suspension, which is twisted by two tangential coolant flows entering through tangential tubes 7 and enters the drying chamber. In the drying chamber, the product is dried, gushing in a swirling flow of coolant. The axial component of the velocity vector of the swirling flow decreases along the height of the conical bottom 3 of the drying chamber, and the rate of product soaring decreases as it dries. Due to this, the product, as it dries, gushes out in a swirling coolant flow and rises to a great height along the axis of the drying chamber. The total flow rate of the coolant is selected in such a way that, having reached the required humidity, the product is removed from the drying chamber, entrained by the waste heat carrier flow through the outlet window 2 of the drying chamber 1. Installing a grate 8 to keep the product in case the dryer stops below the nozzles for supplying tangential coolant flows eliminates the negative its effect on the swirling coolant flow, without destroying it. The final humidity of the finished product can be controlled by the speed of the axial and tangential flows of the coolant, as well as the angle of inclination of the nozzles for supplying tangential flows of the coolant in the vertical direction. By choosing the optimal angle of inclination of the nozzles for the supply of tangential coolant flows in the horizontal and vertical directions, it is possible to achieve the maximum degree of intensification of heat and mass transfer processes and uniformity of swirling of the product and coolant flow with other equal process parameters.

In the event of an emergency stop of the dryer, the product lingers on the grate 8.

Thus, the proposed dryer with active hydrodynamics and after-treatment of the product has the following advantages:

- improving the quality of the finished product due to the lack of accidental entrainment of the wet product coming to the drying along with the dried product due to loading it from below through the feeder together with the coolant coming into the dryer;

- due to the possibility of rotation of the nozzles for supplying the tangential flow of the coolant, the optimal angle of rotation is established at which the maximum intensity of heat and mass transfer processes is observed;

- due to the installation of two nozzles for supplying the tangential flows of the coolant, a greater uniformity of twisting of the product and coolant flows is achieved, which also increases the intensity of heat and mass transfer processes;

- due to the possibility of adjusting the angle of attachment of the nozzles for the supply of tangential flows of the coolant, the dryer can be configured for various drying modes of various kinds of dispersed products;

- the installation of a retaining lattice below the nozzles for supplying tangential flows of the coolant eliminates its negative impact on the formation of a swirling-gushing flow of the coolant.

Claims (1)

An active hydrodynamic dryer containing a cylindrical drying chamber with a conical bottom, a lid and a window for discharging waste heat and dried product, made in the form of a rectangular cutout in the upper part of the drying chamber, with tangentially installed nozzles for supplying a tangential flow of coolant and a nozzle for supplying axial coolant flow, made along the axis of the chamber in its lower part, with a grate for holding the product in case the dryer stops, characterized in that tubes for supplying a tangential coolant flow are installed in the upper part of the nozzle for supplying an axial flow of coolant at an angle of 90 ° symmetrically to the axis of the dryer one against the other, and are made with the possibility of changing the angle relative to the axis of the dryer in horizontal and vertical directions, the grill is located in the lower part of the nozzle for supplying axial flow of coolant, and the pipe for supplying an axial flow of coolant additionally serves as a device for receiving gas suspension, for which it is equipped with by the source product, located above the lattice to hold the product, and has an acceleration section for the starting product.