SU1712754A1 - Shaft furnace for calcination of granulated materials - Google Patents

Abstract

FIELD OF THE INVENTION The invention relates to the chemical industry and makes it possible to increase the uniformity of processing of the material. The material enters the mine 1 self-heating, is heated in the heating zone by heater 10, in the heat treatment zone by heaters 3, 4 and 10, the pump-pulsator creates in the tubular insert alternating movement of the pellet exiting through the perforation and leveling the temperature field in the material. In the lower part of the tubular nozzle there is a nozzle of the Raschig type. 2 Il. .

Description

cl

with

a vibroprobe made in the form of a pipe with rows of holes evenly spaced along its height and provided with cones attached to them fixed in large bases, the lower cones of the nozzles being perforated and installed with a concentric clearance in relation to the pipe. The processed material in this technical solution is subjected to vibration, which leads to disruption of bonds between the particles, the occurrence of transverse mixing of the material. As a result, heat exchange processes are intensified, the temperature field is leveled. The disadvantage of this technical solution is that during the calcination of granular materials (balls, rings, etc.), the imposition of vibration is unacceptable, because it can destroy it. In addition, vibrations at elevated temperatures will quickly destroy the metallic materials of the furnace. And when operating the furnace at temperatures close to and above, when it is required to use ceramic materials of the charge and internal devices, this method of leveling the temperature of the floor is not at all suitable.

The aim of the invention is to ensure uniform processing of the material.

Figure 1 presents a longitudinal section of the shaft furnace, figure 2 - section aa and nafig.1.

The shaft furnace contains a vertical heating shaft 1 in the form of a pipe made of heat-resistant material, enclosed in a lined casing 2, inside of which the main electric heater 3 and the additional electric heater 4 located parallel to the main one are placed. The upper part of the furnace has a hopper 5 with a side suction 6 and a nozzle 7 for the removal of thermal decomposition products. A discharge device 8 is located in the lower part of the furnace. A tubular insert 9 is made along the furnace axis. It is made perforated in the heat treatment zone, and the size of the holes in the perforated part of the tubular insert is obviously smaller than the minimum grain size of the product being processed. Inside the tubular insert is placed a second additional electric heater 10. In the lower part of the tubular insert is placed the heat, heat-resistant gas-permeable nozzle 11 of Raschig type ceramic rings placed on the grill 12. The cavity of the insert is connected by means of a nipple 14 to a volumetric pump pulsator 15. The upper part of the tubular insert is sealed sealing heat and electrically insulating material 16.

A shaft furnace for processing granulated material operates as follows.

The material to be processed is loaded into the bunker 5, from where it flows by gravity into the shaft 1, filling it. When the unloading mechanism is turned on, the material under the influence of gravity moves down the shaft 1, down the passage of the heating, heat treatment and cooling zones in succession.

An electrical heater 10 placed inside the tubular insert 9 heats its walls and through them a product passing through the annular gap between the tubular insert and the walls of the shaft. B. The heat treatment zone transfers heat to the material already from two sides, from the outer side of the shaft walls and from the walls of the tubular insert. From the outer side of the shaft walls, the heat flux is much greater. To compensate for the heat consumption for heating the product and leveling the temperature field of the heat treatment zone in the upper part of the shaft, an additional electric heater 4 is used, which is self-powered and regulated and is located in the lined housing parallel to the main electric heater 3.

Alignment of the furnace temperature floor along the radius is provided by creating a multitude of local alternating gas flows in the intergranular space due to the reciprocating motion of the pulsator pump working body 15 (piston, bellows or membrane). The working volume of the pulsator pump 15 and the oscillation frequency of its working body depend on the required speed of local flows, providing enhanced heat transfer from the hot walls of the shaft 1 and the tubular insert 9 and the near-surface layers of the product to particles located in the middle of the slot of the working space. Alternately pumped gas in the intergranular spaces actively transfers heat from the external walls of the mine inside, while the thermal conductivity of the layer increases by about an order of magnitude.

The proposed shaft furnace design for calcining granular and granular material allows a more uniform product to be obtained by creating a uniform temperature field. Alignment of the temperature field in height and radius (thickness) of the calcination zone actually increases the working volume of the latter and allows to increase the productivity of the furnace with the same dimensions.

In addition, a product calcined in a uniform temperature field is more uniform in its end parameters (pore volume, internal surface and strength, etc.), which is especially important for catalysts.

Claims (1)

A mine furnace for calcining granulated material comprising a heating chamber with a heat treatment zone, The main electric heater and the perforated tubular insert installed inside it, characterized in that, in order to ensure uniform processing of the material, it is equipped with a pulsator pump, two additional electric heaters placed in the upper part of the heat treatment zone and inside the insert perforated in the heat treatment zone, plugged from above above 0 by perforation, and the insert is connected to a pump-pulsor and filling with a nozzle such as Raschig rings.