SU557254A2 - Heat exchanger for coolant gases - Google Patents

Description

one

The invention relates to heat and mass transfer processes, in particular, to devices in which the drying of dispersed materials, such as grains, is carried out and can be used in the agricultural, food and chemical industries.

According to the main author. St. No. 314061 are known heat exchangers for gaseous coolants that can be simultaneously used for settling dispersed materials containing a cooling and heating chambers with a common wall through which heat pipe sections are passed: in the chambers under the tube sections slats are installed to accommodate a dispersed nozzle driven in a fluidized bed state, and one of the chambers is equipped with by-pass channels for the heat carrier connecting the cross-grate spaces of the spaced sections with sublattice spaces a nd downstream sections.

The disadvantage of such heat exchangers when used as dryers lies in the lack of efficiency of the heat and mass transfer process, especially when drying heat-sensitive dispersed materials, such as grain, which, when successively passing through all the drying sections, will be heated beyond the allowable limit.

The purpose of the invention is to improve the processing quality of the dispersed nozzle during the implementation of the drying process.

This is achieved by the fact that in the cooling chamber between the sections equipped with heat pipes and connected bypass channels, there are compartments with gas distribution grids inside, communicated with the sections by means of overflow ducts and connected to independent nozzles of the input and output of the cooling medium; at the same time, a cooler of the dispersed nozzle in a fluidized bed is installed under the lower section.

The drawing shows schematically the proposed heat exchanger.

The heat exchanger consists of cooling and heating chambers with a common wall 1. The cooling chamber contains a hopper 2, drying sections 3, 4 with gratings 5 for accommodating a dispersed nozzle (dried material) located between sections 3 and 4, compartment 6 with the gas distribution grid 7 communicated with Sections 3 and 4 with the help of overflow leakages 8 and connected to the autonomous nozzles 9, 10, respectively, of the input and output of the cooling medium. Under section 4, a cooler 11 of a dispersed nozzle (material to be dried) is installed in a fluidized bed, connected to section 4 by an outlet 12 and having a grate 13, and a discharge pipe 14. A discharge pipe 15 serves to feed the fluidizing agent to cooler 11. Sections 3, 4 are connected by-pass channels 16 for the coolant, which can be used as a fluidizing agent heated upon contact with the nozzle in the cooler 11. To separate fine particles of the material at the exit from

3, a cyclone 17 is installed, and a cyclone 18 is output from the compartment 6. The hopper 2 and chute 8 have feeders 19.

The heating chamber contains sections 20, 21 and with grids 22 for accommodating an inert dispersion nozzle.

The bottom section 21 is connected by a pipe 23 having an adjustment gate 24 to the furnace 25. The upper section 2O has a pipe 26 for exhaust gas emission.

In sections 3 and 20, as well as in sections 4 and 21, heat pipes 27 are located passing through wall 1. In this case, the hot ends are located in sections 2O, 21, and the cold ends in sections 3, 4.

The installation works as follows.

Wet material (grain) from bunker 2 is continuously fed to section 3, where it is fluidized with air and then through the overflow chute 8 enters compartment 6, through which cooling medium is sucked through an autonomous nozzle 9, and leaving through nozzle 10. From compartment 6 the material is fed to section 4 and then to the cooler 11, from where the dried material is discharged through the pipe 14. The specified height of the boiling layers of the material being dried is maintained by means of feeders 19. The heat carrier (flue gases) from the furnace 25 through the pipe 23 provided with a plate rum 24, is directed to sections 21 and 20 with fluidized beds of a dispersed inert nozzle. In sections 20 and 21, the hot ends of the heat pipes 27 are placed, the cold ends of which are placed in the section 60.

wahs of grain dried by this method, 25 the fact of increase in yield as compared to grain, which is by natural means, by 15-20%.

Thus, the proposed heat exchanger allows to improve the quality of the material being dried, due to the implementation of an oscillating drying method, to significantly intensify heat exchange by efficiently organizing the process from the side and flue gases, and to ensure adjustment of the drying mode without changing the flue gas temperature.

Claims (2)

1. Heat exchanger for gaseous coolants according to ed. St. N 314061, which is characterized by the fact that, in order to improve the quality of processing of the dispersed nozzle, carried out during the process, in the cooling chamber between the sections equipped with heat pipes and connected bypass channels, there are compartments with GI inside, communicated with the sections with the help of operatic chutes and connected to the autonomous nozzles of the input and output cooling medium. 2. Heat exchanger according to claim 1, characterized in that a disperse chiller 3, 4 is installed under the lower section. The passage is successively through sections 21 and 20, the flue gases heat the heat pipes 27, which transfer heat in sections 3, 4, and Exhaust flue gases through pipe 26 are emitted into the atmosphere. Shiber 24 regulates the mode of the juice. The proposed heat exchanger is especially effective when drying grain, since alternating heating with cooling helps to preserve the conditional properties of the grain, preventing the evaporation zone from deepening into the grain, and, consequently, drying the grains. This circumstance helps to reduce the magnitude of the temperature gradient and the movement of moisture from the inside of the grains to their surface, which is especially important for the seed grain, since nutrients move with moisture to the surface of the grains and, consequently, to the germ. This explains the fluid bed that was installed with all experienced posenacades.