Blowing ash and unburned fractions from the smokebox into the firebox clogs the latter, and blowing back from the firebox into the smokebox saturates the air in the stoker with dust and carries ash and dust onto the deck. In the case of cooking substandard dust, the fire pipes are filled with incandescent fractions, which, when raked into the stoker, spread over the plates. The removal of slags and ash by ejection does not completely solve the problem, since nevertheless the flue pipes are clogged and they have to be cleaned very often. All this creates complexity and cumbersomeness in maintenance, increases energy consumption for self-maintenance, burdens the character and reduces the efficiency of the installation.
In the event of a change in the brand of coal, it is necessary to adjust the mechanisms, which takes a lot of time, since the maintenance staff does not always quickly adapt to new, sometimes unknown, brands of coal. Changing the brand of coal is not always economically beneficial for this installation and can lead to a negative economic result. This can be observed with increased humidity of coals, with unacceptable grinding fineness and with coals with low volatile yield.
The fact of changing coal grades is often faced by ships that travel far from their bases, sometimes sailing on uncertain routes, and therefore are unable to supply certain grades of coal from permanent bases. This is a significant difference in the supply of fuel to stationary and marine installations. The former are built and adapted to burn fuel of a certain quality, while the latter can receive fuel of random grades during navigation. This circumstance, as well as the clogging of flues by entrainment, are the main reasons why pulverized coal installations are of little use on ships abroad.
The energy consumption for self-maintenance of a vacuum incinerator is high, sometimes reaching 20-25% of the boiler plant's capacity. Only dust preparation motors absorb 6-8% of the power, which is especially unprofitable in low-power installations, such as marine ones, and steam plays a significant role in the cost balance. This applies to all dust preparation systems.
The disadvantages of vacuum combustion in marine boilers include the difficulty of ignition and the need for continuous gorenje or the use of additional heating oil. This can cause great difficulties in operation when maneuvering and parking on steam support (hot reserve), as well as in cases of short-term cargo operations.
For the successful operation of a pulverized coal boiler plant in all modes, it is necessary to have on board up to three types of fuel: fuel for dust ignition, fuel oil for ignition and fuel for servicing auxiliary boilers in the parking lot.
A significant disadvantage of pulverized fuels is the ability of dust to self-ignite and harden during long-term storage, especially at low temperatures. Finding ways to safely store coal dust for a long time could make it possible to collect dust on shore and thus free ship installations from bulky and heavy dust preparation devices. transescort.org/trans/india/delhi/
In the event of a change in the brand of coal, it is necessary to adjust the mechanisms, which takes a lot of time, since the maintenance staff does not always quickly adapt to new, sometimes unknown, brands of coal. Changing the brand of coal is not always economically beneficial for this installation and can lead to a negative economic result. This can be observed with increased humidity of coals, with unacceptable grinding fineness and with coals with low volatile yield.
The fact of changing coal grades is often faced by ships that travel far from their bases, sometimes sailing on uncertain routes, and therefore are unable to supply certain grades of coal from permanent bases. This is a significant difference in the supply of fuel to stationary and marine installations. The former are built and adapted to burn fuel of a certain quality, while the latter can receive fuel of random grades during navigation. This circumstance, as well as the clogging of flues by entrainment, are the main reasons why pulverized coal installations are of little use on ships abroad.
The energy consumption for self-maintenance of a vacuum incinerator is high, sometimes reaching 20-25% of the boiler plant's capacity. Only dust preparation motors absorb 6-8% of the power, which is especially unprofitable in low-power installations, such as marine ones, and steam plays a significant role in the cost balance. This applies to all dust preparation systems.
The disadvantages of vacuum combustion in marine boilers include the difficulty of ignition and the need for continuous gorenje or the use of additional heating oil. This can cause great difficulties in operation when maneuvering and parking on steam support (hot reserve), as well as in cases of short-term cargo operations.
For the successful operation of a pulverized coal boiler plant in all modes, it is necessary to have on board up to three types of fuel: fuel for dust ignition, fuel oil for ignition and fuel for servicing auxiliary boilers in the parking lot.
A significant disadvantage of pulverized fuels is the ability of dust to self-ignite and harden during long-term storage, especially at low temperatures. Finding ways to safely store coal dust for a long time could make it possible to collect dust on shore and thus free ship installations from bulky and heavy dust preparation devices. transescort.org/trans/india/delhi/