Improved control of burners and boilers delivers efficiency savings
Published: 26 November 2015 - Lisa Peake
The use of boilers and their associated burners is widespread across a large number of industries and they form a crucial part of many processes, especially for the generation of saturated steam. However, with ever-increasing fuel costs and the heightened focus on CO2 emissions, it is becoming more important than ever to ensure that the efficiency of this equipment is maximised.
In general, boilers use either oil or gas as the fuel source, although biomass is becoming a more widely used fuel as the cost of fossil fuels continues to rise and customers look for a more sustainable heating solution. For those remaining with oil and gas, the design of modern boilers has changed considerably in order to meet the latest legislation as well as improving efficiency.
The need to reduce NOx emissions has led to the development of flue gas recirculation (FGR) which involves up to 25% of the flue gas being returned to the burner, improving combustion efficiency and reducing NOx levels to as little as 25% of their normal levels. Although extremely effective, FGR may not be suitable for all applications such as those with high temperature flue gases or those with elevated oxygen levels.
When operating an oil-fired boiler the overall efficiency of the fuel is largely due to the particle size of the oil and its viscosity which requires accurate measurement of temperature and pressure in order to give a consistent fuel jet and maximise the efficiency of the burner. Bürkert
has developed a range of pressure transmitters which provide a standardised 4-20mA output and are easily installed and integrated into the control loop to provide accurate and reliable data. The measurement of temperature can be accomplished with an integrated transmitter such as the Type 8400 which has been designed to provide information via the built-in display as well as an analogue or fieldbus signal.
Accurate burner control should also be combined with safe operation which means the inclusion of safety shut-off valves within the design of the oil burner control loop. Bürkert offers a range of TÜV-certified solenoid valves which have been designed with stringent quality controls to deliver functional reliability and low maintenance operation.
The gas-fired boiler requires accurate and reliable flow measurement and flow control in order to allow the boiler to be matched to the demand of the system and thereby ensure a cost effective and efficient application. Bürkert's considerable experience in gas handling has produced a wide range of monitoring and control devices which include the latest gas flowmeters which use the calorimetric principle of flow measurement. This design enables the Type 8007 and 8008 flowmeters for example to measure large flow rates with assured accuracy since they are unaffected by changes in temperature and pressure.
Source: Energy Management