Industrial Combustion Boilers

PROCESS AND TECHNOLOGY STATUS – Combustion boilers are widely used to generate steam for industrial applications and power generation. While all kinds of energy sources fossil fuels, biomass, nuclear and solar energy, electricity can be used to generate heat and steam, the scope of this brief is limited to combustion boilers using fossil fuels and biomass. Boilers can be grouped into two broad categories: water-tube boilers and fire-tube boilers. In the water-tube boilers, tubes containing water are heated by combustion gases that flow outside the tubes, while in the firetube boilers hot combustion gases flow inside the tubes and water flows outside. Key design parameters to determine the boiler size and power are the output steam mass flow rate, pressure and temperature. Since the first boilers were used in the 18 century, the design of boilers has evolved so as to increase efficiency as well as steam pressure and temperature. In the United States, the energy consumption of industrial boilers accounts for 37% of total energy use in the industrial sector. In the industrialised countries, more than 50% of the industrial boilers use natural gas as the primary fuel and about 76% of the total boiler population is older than 30 years. Boiler sales in 2002 amounted to 1/6 of the total sales in 1967.