RAJ Hot Air Generators are tailor-made to suit individual requirements. The units are self-contained, ready to install immediately after power supply is given.
RAJ Direct Fired Hot Air Generator:
The combustion chamber is enclosed in a concentric shell with suitable lining. The fresh air from dynamically and statically balanced blower is fed to the chamber tangentially. The air envelopes the combustion chamber and absorbs the radiant heat from its surface and then mixes with completed combustion gases in a conical chamber.
Hot air, thus generated is let out from Hot Air generator at controlled temperature to the process. Most of the times the combustion chamber is refractory lined. The thermal efficiency is almost 100% with proper insulation and air temperature can be up to 1100 deg.C.
The Combustion Chamber is made out of SS 316 to withstand high temperatures. The combustion is completed within the chamber. Hot gases, after complete combustion are passed through Tube Heat exchanger, comprising of second & third pass.
The systems are available with Light fuel oil and/or Gas fired, backed by fully automatic burners.
Indirect fired hot air generator types are:
- Fuel fired HAG
- Steam/ Thermic Fluid heated air heater
This consists of multiple shell in shell construction or shell and tube construction. The process air does not come in contact with the flame or the combustion gases. The combustion gas path and process air paths are different. The heat from flue gases is recovered for maximum thermal efficiency. Thermal efficiency up to 88% are easily achieved in these hot air generators. Air temperatures up to 350 degree C are possible in these types of heaters. The material of construction of combustion chamber is SS 310 and the outer shells are either made up of carbon steel and spray galvanised or are made up of stainless steel. For GMP plants the complete construction is in stainless steel.
These consist of a bank of fin tube radiators. The process air passes over the fin tubes through which either steam or thermic fluid flows. Thus indirect heating of air takes place. Temperatures from 250 to 300 deg. C are achievable depending upon the steam and thermic fluid temperatures. The material of construction of tubes is either carbon steel or stainless steel depending upon process requirement. The mounting of these heaters can be either horizontal or vertical.
Design Aspects
- The HAG direct fired design is suitable for Light oil, Heavy oil, Natural Gas, LPG, Dual firing for Oil and Gas.
- The HAG in-direct fired design is suitable for Thermic Fluid, steam any other suitable heating media to increase the temperature of process air.
- The HAG design is suitable for high turn down ratio.
- Higher thermal efficiency to reduce fuel cost.
- Steam Heater design is suitable for vertical installations also.
- The tube can be in various constructions like stainless steel, copper, aluminum etc.
Features of RAJ Hot Air Generators:
- These Hot Air generators are manufactured upto capacity of 5.0 million Kcal/hr. Higher capacities are also available.
- Efficiency in these hot air generators is nearly 100% since surface losses are taken care of with proper insulation.
- Specially designed systems can be offered suitable for temperatures upto 700 degree C.
- Direct Fired and Indirect Fired HAG are available.
- Raw mill, Coal mill & Cement – clinker grinding.
- Dryers (Fluidised Bed, Flash, Husk, Rotary & spray.
- Calciners
- Auxiliary in line heaters etc.
Raj solid fuel fired hot air generators
are offered in vertical or horizontal designs,
either as standard models or tailor-made
models to match customer's specifications
and applications. Designed in DIRECT and
INDIRECT heating types, these systems
are practically free from any maintenance
and are highly efficient.
Direct systems find their applications in
high temperature drying, whereas the
indirect systems are used where pure air is
required for drying. The design is compact
& hence space saving. Units are designed
for continuous round the clock operation.
Air temperature up to 350 degree C is
possible in indirect type and 800 degree C
in direct type air heaters.