1) The entire plant may be purchased as a complete package, only needing securing to basic foundations, and connecting to water, electricity, fuel and steam systems before commissioning. This means that installation costs are minimised.
2) This package arrangement also means that it is simple to relocate a packaged shell boiler.
3) A shell boiler contains a substantial amount of water at saturation temperature, and hence has a substantial amount of stored energy which can be called upon to cope with short term, rapidly applied loads.
*This can also be a disadvantage in that when the energy in the stored water is used, it may take some time before the reserve is built up again.
4)The construction of a shell boiler is generally straight forward, which means that maintenance is simple.
5)Shell boilers often have one furnace tube and burner. This means that control systems are fairly simple.
Although shell boilers may be designed and built to operate up to 27 bar, the majority operat
The flue gas first enters the cyclone dust collector which acts as a primary dust collector to make the large dust particles in the flue gas settle down. The cyclone dust collector is a dust removal device which uses the centrifugal force generated by the cyclone flow to separate the dust particles from the air flow. Afterwards, the flue gas enters the wet scrubber dust collector which is a circular-type cylinder. The circulating water enters the dust collector from the upper overflow tank to form a uniform water film on the inner wall of the dust collector. The flue gas is induced tangentially or spirally from the lower part of the cylinder and rotates in the cylinder. Under the influence of the centrifugal force, the dust particles are separated from the flue gas and then the flue gas is also spirally led out from the top of the cylinder. The dust particles are thrown to the water film, transferred to the bottom and finally discharged from the dust port.
Whether the water quality in the gas-fired boiler reaches the required standards is directly related to the safety, performance and service life of boiler. The water must be treated before the boiler operation. However, what are the water quality standards for the gas-fired boiler?
A water level sensor fail on a steam boiler is extremely dangerous. The low water cut of should be tested daily. If the sensor fails the boiler could turn all the water into steam, leaving the boiler dry. Without water in the boiler the flame from the burner would heat up the heating surface to extreme temperatures and would crack and damage the inside of the boiler. But that’s not the dangerous part. If water added to boiler while it is extremely hot. Once water touches the extremely hot heating service, water would immediately start to evaporate into steam. When water evaporates it expands 18x it’s original size. The boiler would explode from the sudden increase in pressure from the inside. Some in some cases, boilers that have exploded out of a building and have landed 100s of feet away.
There are many opinions on the best way to clean a steam boiler. One of the oldest ways is to dissolve a pound of tri-sodium phosphate (TSP) and a pound of caustic soda (lye) in water and pour it into the boiler. Let it cook for a few hours and then drain the boiler. If you can't buy TSP in your town, try a commercial soap called MEX. It works well and will not damage the rubber gaskets found in some boilers. However, before you clean any boiler, check the manufacturer's instructions for their recommendations.
Few parameters critical to health of the Boiler are
(4)Heat rate of the Boiler. This is a composite index of many performance indicators. Most of them will appear below.
(5)Unburnt fuel in flue gas and at boiler bottom .
(6)Flue gas furnace exit temperature.
(7)Boiler tube metal temperatures.
(8)Oxygen in flue gas.
(9)Imbalances in flue gas temperature over a cross section.
(10)Spray water consumption in Super heater and Reheater.
(11)Heat radiation from insulation.
The above all affects the performance of the boiler.
Biomass-fired boilers need to be shut down for maintenance. Proper maintenance can reduce the damage to the boiler caused by continuous work. Firstly, it is necessary to cut off all power to prevent being struck by lightning. In addition, dust, limescale and carbon deposits should be cleaned up to prevent rust and corrosion of the boiler.
Evaporation phase occurs in water wall tubes. Evaporation is the process to convert water into steam. Therefore water wall tubes should be designed and constructed to provide high heat absorption, minimum excess air level and highest boiler efficiency. Construction of water wall tubes should be also constructed to prevent air leakage into steam boiler, eliminate amount of heat losses and permit high heat release and combustion rate in the furnace.
Construction of water wall tubes must provide high quality of the supporting component such as tubes, casing, refractory, lagging, tile, fin, and so on. Best construction will reduce heat loss and maintenance. Construction of water wall tubes can be classified into four types such as:
