A UL steam boiler from Loos (now Bosch) with an output of four tons of steam per hour has been responsible for supplying the process steam since 1978. For efficient use of the hot flue gases, which are up to 230 degrees Celsius, an economizer from Bosch Industriekessel is now in use. The boiler feed water is preheated while the flue gas temperature is reduced by around 100 degrees Celsius. The boiler efficiency is increased by a reduction in flue gas losses of approximately five per cent, the fuel consumption is likewise reduced at full load.
The replacement of the existing light oil burner with a modern dual burner resulted in a further increase in efficiency. Natural gas is used as the main fuel and light fuel oil is only used during peak load operation or in an emergency. An electronic compound control now ensures correct dosing of the fuel/air ratio. In comparison to the mechanical compound control of the old burner, this achieves a more precise setting for the air supply and reduces the fuel consumption accordingly. In addition, the new firing enables completely infinitely variable operation. Combined with a high turndown ratio, switching the burner on and off, which goes hand in hand with energy loss, is considerably reduced.
The motor speed is reduced in relation to the burner capacity through the use of speed regulation. The electrical power consumption in the partial load range is considerably lower and at the same time there is also a significant reduction in the sound pressure level. Even the oxygen content in the flue gas is continually recorded. If this is too high, and the combustion is thus ineffective, the volume of combustion air is reduced. The oxygen regulation thus optimises the efficiency of the burner system, reduces its environmental impact, and helps to save energy costs.
The newly integrated boiler control BCO comes with all the necessary information and functions for operation according to need. An intuitive touchscreen display indicates operating states, operating data, and measured values as well as operating settings. The retrofitting project was planned by the IGS Ingenieurbüro in Hallbergmoos while the Ernst Huber Wärmetechnik GmbH in Rott am Inn carried out the installation.
All you need to know about the innovative boiler system technology along with further solutions from the fields of combined heat and power, waste heat recovery, heat pumps, and solar heat can be found at the Bosch stand at the Drinktec trade fair in Munich between September 16-20, 2013 in Hall B6, Stand 100.
