Comparison or difference between high pressure and conventional boiler are as follows:
(1) Fuel burning process: High pressure boilers can be utilized fuels like oil, gas or coal; they have modified burning system and special types of burner.
(2) Flue gas path: Pressurized combustion provides uniform heating, minimum friction losses, reducing overheating and maximum heat transfer is possible.
(3) Circulation of water: Forced circulation of water provides high heat transfer rate and less scale formation tendency.
(4) Size/shape/space: Compact, no drum, less space requirement.
(5) Design/arrangement: Better design and different parts arrangement lead to increased heat transfer surface area, so increased efficiency of boiler.
(6) Pressure/capacity range: In HP boilers, Steam is generated at high pressure 160 bar and above even supercritical pressure (above 225 bar), steaming capacity 30 to 650 tones/hr, temperature range 500-540°C.
(7) Fuel consumption: Lower as 250 Tones/hr
(8) Waste disposal/draught system: High pressure boiler uses modified draught system and hence, there is reduction in pollutions.
You will be able to answer following questions
Q1. What are the main features of high pressure boilers? Why are they preffered for thermal power plants ?
Q2. Explain the constructional difference between low pressure and high pressure boiler
Q3. Explain the advantages of using high pressure boilers in thermal power plants.