Fire-tube boilers are generally limited in size to approximately 25,000 lb/hr (11,340 kg/hr) and 250 PSIG (1.7 MPa) saturated steam. A typical coal-fired utility boiler might produce 3 million lb/hr (1.36 million kg/hr) of superheated steam at 2400PSIG (16.5 MPa). A typical nonelectric utility industrial boiler might produce 400,000 lb/hr (181,000 kg/hr) of steam at 900 PSIG (6.2 MPa). Industrial boilers are commonly referred to as Co-Generation or combined heat and power (CHP) applications. 3 Dept. of Electronics & Instrumentation, Narayana Engineering College, Nellore.
Balancing total energy entering a boiler against the energy that leaves the boiler in different forms Heat in Steam BOILER Heat loss due to dry flue gas Heat loss due to steam in fuel gas Heat loss due to moisture in fuel Heat loss due to unburnts in residue Heat loss due to moisture in air Heat loss due to radiation & other unaccounted loss 12.7 % 8.1 % 1.7 % 0.3 % 2.4 % 1.0 % 73.8 % 100.0 % Fuel 73.8 % Heat Balance 7 Dept. of Electronics & Instrumentation, Narayana Engineering College, Nellore.