Field of applications include
- molasses from the foodstuffs
- cosmetics industries
slurry from the cosmetics and soap industries- sludge`s from agriculture, communal and industrial effluents.
products and by-products in powder form or forms similar to powder from industrial processes such activated carbon, waste products from tea and coffee production and coated broken repulped particles from the paper industry etc.
The resultant products leave the evaporation chamber with a dry substance content of 80 to 99%, which can be adjusted, depending on further processing.
The pre-dewatered material whose water content varies depending on the properties of the relevant product to be dried is pumped by a feed pump through a heat exchanger into the loading unit of the patented POLYTHERM® belt drying system. The material to be dried is fed from the cutting mechanism through the output opening onto the high-grade steel mesh belt. Rotating blades which periodically close off the exit openings output the product in the form of individual, pressed pellets or in the form of a sort of pressed granulate. Opposite to the high-grade steel mesh belt, there are several heating elements along the belt conveyor, distributed between the input device and an unloading lock through which the dried material leaves the drier.
By contrast with conventional belt driers, the POLYTHERM® belt drier operates with infrared radiation. An appropriately tight array of heating tubes which are heated so that they emit in the infrared band in the area specified forms a high-temperature zone. The heat is issued at this point by the heating tubes in the form of radiation and convection. This abruptly forms a crust on the surface of the material to be dried. Drying is performed by convection in the downstream area.
Closed Process Air Circuit System
In a closed process air circuit, the air at the downstream end of the high-grade steel mesh belt is ducted into the drying chamber and flows through the chamber in a direction opposite to the direction in which the material to be dried is conveyed. As it passes through the drying chamber, the air is heated and saturated with moisture originating from the material to be dried. The air leaves the drying chamber on the upstream side.
The process air ducting system now routes the hot air, saturated with water, to the condenser. The air is then cooled and the condensate is routed to the drainage pipe. The air which is now cool again is routed through a further fan to the flue gas heat exchanger. There is an additional fan, used to feed fresh air into the process circuit, if required between the fan and the flue-gas heat exchanger.
Fast flow through: The dwell time of the product in the evaporation chamber depends on the speed of the conveyor belt and the length of the POLYTHERM® belt drier. It is between 8- 15 minutes depending on product and required final dry substance content. Evaporation of the water escaping from the material to be dried occurs at a slight partial vacuum. This eliminates the possibility of vapour emission from the plant.
Individual system sections, such as the drying chamber, may be arranged one on top of the other or side-by-side and may be combined so as to produce a drying system with several drying lines.
View plan summaries.
Efficient Use of Energy
It goes without saying that the walls of the POLYTHERM® belt drier features an exothermic thermally insulated design to supply additional heat loads with heat.
The system is controlled with MIPOS® (Modular integrated process control and optimisation system).
Minimal Labour Coasts
The drying system which has a mechanically simple design requires a sophisticated measurement and control system, in particular if different products are to be processed with the same system.
MIPOS® incorporates control intelligence in a PC. All variable operating parameters are controlled on a personal computer running under the Windows NT® operating system.
Variable Input Products
The system integrates a system database, linked to a knowledge database and an automatic operator. This means that MIPOS® is aware of all changes made manually and, at a later point, can signal these deviations to the user, display to the user corresponding proposals for adjustment of the corresponding operating parameters or correct the parameters itself if an identical or similar situation occurs subsequently.
Optimised End Product
Thanks to the combination of MIPOS® and POLYTHERM® belt drier, it is possible simultaneously to optimally achieve different, required specifications of the material to be dried. The following parameters can be set, amongst others, depending on how the material to be dried is to be used:
- length of the pellets
- diameter of the pellets
- shape of the pellets
- density and strength of the pellets
When drying sewage sludge, liquid manure and manure etc., working with drying temperatures of over 200°C achieves complete disinfection of the output material. The advantage: Both work steps, disinfection and subsequent drying, are performed in one operation. This allows the operator to save on the expense of a disinfection system.