The choice between a steam system or a thermal fluid system is governed by the process requirements. The range or process temperature is a deciding factor. If the system’s required temperature is above the freezing point of water (0°C) and below approximately 160°C, the choice is usually steam. However, if the required temperature is above 160°C, thermal fluid may be a better solution. Thermal oil heater systems can be designed with maximum operating temperatures to 325°C.
The boiler gas consumption calculation need the following parameters: gas calorific value and boiler thermal efficiency.
Theoretically, the gas consumption of boiler = boiler thermal capacity ÷ (calorific value of gas x boiler thermal efficiency )
Take the 1 tph steam boiler as an example:
= 600,000 cal / (8500Kcal * 0.98) =72m3/h, the 1 tph boiler's gas consumption per hour is about 72 cubic meters.
The main sectors in which industrial steam boilers are used are:
Food, in industrial bakeries or baby food (as an example)
Textile, in rotary dryers
Chemical, for reactors or storage
Pharmaceutical, for the manufacture of medicines
Cosmetics, for the production of perfumes and creams
Stationery and printing, in drying tunnels
The cement industry, for the manufacture of cement parts
Oil, for the storage and distribution of heavy oils
Wood, involved in the process of melanin production
Hospitals and hotels, especially in the laundry and kitchen areas
Automotive and surface treatment, for the final metal finishing.
The primary objective of an industrial boiler is the generation of steam. Steam is generated by heat transfer at a constant pressure. The fluid, which is initially in a liquid state, is heated, produces a variation in its phase and becomes saturated vapour.
This saturated steam can then be used for different applications such as sterilization, fluid heating or electricity generation.
Any boiler where the products of combustion flow on the inside of a tube with the heat transfer media (ex. water, steam, or hot oil) on the outside. The tubes can be orientated vertically, horizontally or at an angle.
Steam carries about 540 Kcal/kg of useful energy whereas hot water and thermal fluid carry much less energy. Steam does not require a pump to transfer the energy. Generally, if the heating temperatures required are <100°C, then hot water can be used and if temperatures >180°C are needed then thermal fluid might be a better choice. For process temperatures between 100°C and 180°C steam is considered a viable option.
All thermal fluids expand as they are heated. The amount of expansion is based on the operating temperature, system volume and the coefficient of thermal expansion of the fluid. An expansion tank must be provided to accommodate the increased system volume at operating temperature.
NOTE: All fluids expand at a different rate.
A typical system includes the heater, circulation pump, expansion tank, and the user's process. Depending on the temperature requirements and the system design control valves may also be utilized.
