RU2801286C1 - Process line for production of expanded clay in a plastic manner - Google Patents

Abstract

FIELD: building materials industry.

SUBSTANCE: invention relates to enterprises for production of expanded clay. The process line for the production of expanded clay by plastic method includes process devices installed and interconnected by means of conveyors: raw material warehouse 1, loader 2, supply hopper 3 with feeder, rollers 4 for grinding raw materials. From rollers 4, the processed raw material is fed by conveyor 5 directly into twin-shaft mixer 6. From mixer 6, the processed raw material is fed into extruder belt 7, which is equipped with quick-change dies 8 connected to knives 27 for cutting granules mounted on the shaft of extruder 7. Quick change dies are shown schematically in Fig. 3 and the 25 themselves are put on feed screw 25 and attached to extruder body 26. The outlet part of dies 8 is installed so that the cut granules roll directly into drum-type dryer 9 onto the blades, where they are smoothly dried and heated. The granules, when leaving drum-type dryer 9, are rolled up and stacked in one layer on the conveyor belt in kiln 11 through granule distributor 10. The granules moving on the conveyor in one layer pass a zone of heating and intensive roasting. After firing, the granules enter conveyor-type refrigerator 12, and then into drum-type refrigerator 13, where they undergo zone cooling. After cooling, the granules are lifted by elevator 14 and poured onto fractional sieve 15. Rolling down the inclined mesh troughs of sieve 15, the granules, according to the size of the sieve cells, fall into hoppers 16 with loading devices. Mechanisms 17 are installed under the hoppers for filling finished products into bags or containers. The conveyor-type firing furnace consists of furnace body 19, burners 20, conveyor 21, drive 22 of adjustable conveyor 4, distributor 23 of granules 5.

EFFECT: improved quality of expanded clay by simplifying the manufacturing technology of expanded clay, increasing the productivity of the furnace and the production line, expanding the range of fired materials.

1 cl, 3 dwg

Description

The invention relates to the building materials industry, namely to enterprises for the production of expanded clay.

Rotary kilns are most widely used for the production of expanded clay gravel.

An analysis of the known methods, automation tools and automatic control systems for rotary kilns for firing expanded clay showed that their use does not fully solve the actual problem of producing expanded clay gravel with a stable required strength value.

Known, serious shortcomings of common rotary kilns for the production of expanded clay: the instability of the release of aggregate in terms of strength and density; the difficulty of firing weakly swelling clays with a small interval of swelling; the impossibility of creating in them the required stepwise mode of heat treatment of granules for expanded clay.

An analysis of known methods, automation tools and automatic control systems for rotary kilns for firing expanded clay showed that their use does not fully solve the actual problem of producing expanded clay gravel with a stable required strength, particle size distribution, and specific gravity.

Known technological scheme for the production of expanded clay, described in the annular furnace for firing expanded clay (patent 1795246, IPC F27B 13/06, op. 15.02.1993), which uses a modernized annular rotary hearth furnace, widely used in the metallurgical industry.

In general, the technological scheme for the production of expanded clay on the specified line provides for the formation of raw granules on a belt brick-making press, drying in a drying drum with granules running in it, heating the semi-finished product in a layer heater to approximately 200-250 ° C, followed by swelling of the granules in an annular furnace for continuously rotating hearth with its single-layer loading, cooling, sorting and storage of filler. The roasting unit of the technological line includes a layer heater, an annular roasting furnace and a cooler-air trough. The annular furnace consists of stationary walls 750 mm thick and a vault with a heat-insulating backfill - 700 mm, a rotating hearth (including a metal platform, a lining 500 mm thick, an annular roller table), a water seal. The average diameter of the ring kiln is 11.25, the width is 2.4, the height from the hearth surface to the vault lock is 0.81 m. - 19 m.

The expanded clay production technology is based on the Thermidor method with firing of granules in a monolayer, which allows the granules to be heated quickly, thereby creating favorable conditions for intensive pore formation. The firing in one layer is so fast that the total capacity of the annular kiln is equal to that of the rotary kiln with an equal ratio of their lengths.

In an annular furnace, where pellets are fired in a fixed monolayer, as compared to firing in a pouring layer in rotary kilns, the conditions for heat exchange between the fuel combustion products, the heated furnace elements and the fired material are improved. This is due to the elongation and alignment of the heating zone of the material with the fuel combustion zone and the development of a heat-assimilating surface of the material with its discrete distribution on the surface of the hearth. The consequence of this is an increase in the heating rate of the material up to 350-400°C per minute, which provides the optimal technological firing mode - thermal shock. The intensification of the expanded clay firing process determines the high productivity of the annular furnace with its small dimensions. Ring furnaces operate on any type of raw material. Finished granules are 25-40% lighter than when fired in drums, their density can be reduced to 280-425 kg/m3. The specific fuel consumption is significantly reduced - by 35…45% compared to production in single-drum furnaces, and amounts to 52…60 kg/m ³ of reference fuel.

The disadvantage of these technological lines is the bulkiness of the equipment, the large weight of the roasting complex (the weight of the rotating hearth is about 15 tons), the need to use circulation gas ducts with adjustable dampers and the need to control the aerodynamic regime with dampers on the main and recirculation gas ducts, which creates difficulty in controlling the stabilization of firing. The loading of pellets into the furnace in a monolayer is carried out by a drum unloader, the removal of pellets from the hearth is carried out by a hearth unloader, additional technical devices. If the thermal insulation or hearth fails, it is extremely difficult to carry out repairs.

The objective of the invention is to create small-sized technological equipment that increases the productivity of the expanded clay production process and its quality and high repair ability.

The technical result from the implementation of the invention is to obtain a product of increased quality through the use of a simplified manufacturing technology of the product, full automation of production, a rapid change in the technological parameters of firing, an increase in the productivity of the furnace (and the production line as a whole), and the expansion of the range of fired materials.

This is achieved due to the fact that the Technological line for the production of expanded clay in a plastic way is a technological scheme operating in full automatic mode. In the production line for the production of expanded clay by the plastic method, containing a granulator and a conveyor-type firing furnace, according to the invention, all equipment is installed interconnected into a single continuous production line and includes a supply hopper with a feeder for supplying raw materials, a loader, a conveyor, rollers for grinding and grinding raw materials , twin-shaft mixer, belt extruder, which is equipped with quick-change dies connected to granule cutting knives mounted on the extruder shaft, the outlet part of the dies is installed in such a way that the cut granules can roll directly into the drum-type dryer on the blades, granule distributor, roasting oven, refrigerator conveyor and drum type, elevator, fractional sieve, hoppers with loading devices, mechanisms for filling finished products into bags or containers installed under the hoppers, while the kiln is equipped with a conveyor as a means of moving the granules.

The invention is characterized by the possibility of a compact arrangement of equipment, where part of the auxiliary mechanisms is removed, due to the use of a small size and weight of the main equipment, and using these qualities, the equipment can be installed in two or three tiers close to each other, which will simplify and shorten the production line , i.e. simplify the technological process, automation and control, and the supply of flue gases directly from the kiln to the drying drum for drying and heating the granules allows to reduce fuel consumption, fully automate the production process from the supply of raw materials to loading the granules into the hopper, which guarantees high-quality manufacturing of products and reduction the number of workers. The extruder, equipped with interchangeable dies of a certain diameter, guarantees the release of granules of a certain fraction and size. The use of a furnace with a conveyor for the continuous advancement of pellets in the zone of intensive firing i.e. thermal shock, scattered in one layer, allows for rapid heating and swelling of the granules in a few minutes, which significantly speeds up the firing process, followed by the supply of the burned granules to the conveyor and drum-type refrigerator, after which the cooled products are loaded by an elevator or conveyor onto a fractional sieve, which distributes granules in bunkers.

The essential difference between the invention and known analogues is as follows.

What is new is that the amount of intermediate equipment has been reduced, eliminating manual labor. Simplification of the technological scheme and equipment contributes to the improvement of process control, increases control and quality, and significantly simplifies the conditions for repairs. Installed on the extruder, quick-change dies allow you to change the size of the produced granules without stopping the process.

The use of a conveyor in a kiln with a decrease in the height of the roof above the conveyor belt to 300 mm creates conditions for intensifying the heat transfer process, this makes it possible to increase the heating rate of the material to 300 ... 400 ° C / min, which ensures high-speed firing (thermal shock). The firing time has been reduced to 3-5 minutes instead of 10-15 minutes. The stability of the temperature regime in this kiln and the rapid change in firing modes makes it possible to use clays with short (less than 50°C) temperature expansion intervals. The conveyor-type cooler allows you to quickly cool the granules to the first critical point. Further thermal exposure, according to the recommended cooling schedule, is carried out in a drum-type refrigerator.

The essence of the technological line for the production of porous materials is illustrated by figures.

On FIG. 1 shows a diagram of a production line for the production of expanded clay by a plastic method, a general view.

On FIG. 2 - also, a diagram of a transport-type kiln, a general view.

On FIG. 3 - also, quick-change dies, section, general view.

Positions designate: warehouse of raw materials 1; loader 2; supply hopper with feeder 3; rollers 4; conveyor 5; two shaft mixer 6; belt extruder 7 with replaceable dies 8; drying drum with heating from flue gases 9; pellet distributor 10; conveyor-type kiln 11; conveyor refrigerator 12; drum type refrigerator 13; elevator 14; fractional sieve 15; hopper with loading devices 16; mechanism for loading into bags 17; exhaust fan 18; furnace body 19; burner 20; conveyor 21; adjustable drive 22 conveyor 5; distributor of 23 granules; fired pellets 24; auger 25; extruder body 26; knife 27; intense firing zone (impact term) 28; heating zone 29.

The technological line for the production of expanded clay in a plastic way is a technological device installed and interconnected by means of conveyors: a raw material warehouse, a supply hopper 3 with a feeder, a loader 2, rollers 4, for grinding and grinding raw materials. From the rollers 4, the processed raw material is fed by the conveyor 5 directly to the twin-shaft mixer 6, where the raw material is additionally mixed, blended with additives and moistened, if it is technologically necessary. From the mixer 6, the processed raw material is fed into the extruder belt 7, which is equipped with quick-change dies 8 connected to the cutting knives 27 of the granules mounted on the extruder shaft 7. The quick-change dies are schematically shown in Fig. 3 and the dies 25 themselves are put on the feed screw 25 and attached to the body of the extruder 26. The outlet part of the dies 8 is installed so that the cut granules roll immediately into the drum-type dryer 9 onto the blades, where they are smoothly dried and heated. The granules, when leaving the drying drum 9, are rolled up and placed in one layer on the conveyor belt in the firing furnace 11 through the granule distributor 10. The granules moving on the conveyor in one layer pass through the heating and intensive firing zone. After firing, the granules enter the conveyor-type refrigerator 12, and then into the drum-type refrigerator 13, where they undergo zone cooling, according to the technological requirement. After cooling, the granules are lifted by the 14 elevator and poured onto the 15 fractional sieve. Rolling down the inclined mesh troughs of the 15 sieve, the granules, according to the size of the sieve cells, fall into the 16 hopper with loading devices. Mechanisms 17 are installed under the bunkers for filling finished products into bags or containers. Finished products are transported to the warehouse. Adjustment of the supply volumes of hot gases into the drying drum 9 for heating and drying the granules, as well as for adjusting the cooling of granules with cold air in the refrigerators of the conveyor 12 and drum 13 type is carried out by exhaust fans 18. The conveyor-type firing furnace consists of a furnace body 19, burners 20, a conveyor 21, drive 22 of adjustable conveyor 4, distributor 23 of granules 5.

The technological line for the production of expanded clay by the plastic method using a conveyor-type furnace has significantly smaller dimensions, weight, reduces the amount of intermediate equipment, simplifies and creates a more compact technological scheme that allows it to work in fully automatic mode. Compact rational placement of equipment using high-speed firing (thermal shock) and the ability to fine-tune the movement of raw materials and products throughout the line significantly reduce technological and energy losses. This technological scheme allows for the secondary utilization of the generated heat from flue gases, which reduces fuel consumption per unit of production. All this makes it possible to significantly improve the technical and economic performance of the proposed production line in comparison with analogues intended for the same purpose.

Claims (1)

Technological line for the production of expanded clay in a plastic way, containing a belt extruder and a firing oven, characterized in that all equipment is installed interconnectedly into a single continuous production line and includes a supply hopper with a feeder for supplying raw materials, a loader, a conveyor, rollers for grinding and grinding raw materials, twin-shaft mixer, belt extruder, which is equipped with quick-change dies connected to granule cutting knives mounted on the extruder shaft, the outlet part of the dies is installed in such a way that the cut granules can immediately roll into the drum-type dryer on the blades, granule distributor, roasting oven, conveyor coolers and drum type, an elevator, a fractional sieve, hoppers with loading devices, mechanisms for filling finished products into bags or containers installed under the hoppers, while the kiln is equipped with a conveyor as a means of moving the granules.

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