Incidents of boiler and crankcase explosions are quite heard of on board a ship. But can an air compressor burst? Technically, an air compressor is also equally potent to explode because of all the extreme parameters it deals with as we have seen in the article – "How marine air compressors work?" Air compressors have to withstand high pressures along with equally high temperatures. Although compressors have necessary precautions such as relief valves to prevent incidences of over pressuring, a situation involving fire is a totally different matter.
What Causes Explosion?
It is very important to keep in mind that an air compressor has all the things that are required for a perfect explosion. A fire propagates at a very fast rate when three things are easily available – fuel, oxygen and heat source. This is also known as the deadly fire triangle which needs to be avoided in all cases where there is a possibility of explosion or fire. A compressor is a rich source of highly compressed air and when it gets in contact with other two sources, an explosion is bound to take place.
Probably the next question that might arise is to how does an air compressor get fuel for explosion? It is to note that most of the ships use oil lubricated compressors and it is the lubrication system of these compressors that provide the necessary fuel for a probable explosion. One more potent source of fuel is the carbon deposits that are created when the oil heats up at high temperatures.
The last and the most easily producible factor – the heat source, can be generated due to variety of reasons.
The most common source of heat source is heat generated due to friction between two surfaces. Lack of proper lubrication is the most common cause for heat generated in this way. However, lack of lubrication can also be due to degradation of lubricating oil, faulty lubricating oil pump, chocked oil filter, worn out parts etc. These are the prime reasons for the developments of hot spots.
The lack of lubrication will increase the wear and tear of the moving parts of the compressor, deteriorating the quality and operation of the compressor. As the components continue to operate poorly, carry over of the oil to the air passages takes place, increasing the temperature of that area. Also, it is very important to remove this heat generated. If proper steps are not taken to remove the heat, heat build up will take place increasing the temperature substantially. Inter-coolers play an important role in this heat removal and thus need to be properly working.
Lack of cooling can also occur when the heat transfer surfaces are covered with scales or carbon deposits, thus affecting the cooling process. Choked passages of the heat exchangers can also be a reason. Sometimes the cooling medium itself is hot due to faulty machinery, thus providing negligible heat transfer.
Non-continuous supply of coolant might also be a reason. This happens when the cooling pump fails or the valves of the coolant line are stuck or accidentally closed. An explosion occurs when all the above mentioned factors come together to make a vicious cycle that ultimately leads to explosion.
Sometimes the oil film in the pipes also turns to deposited carbon, which is already having a high temperature. The compressed air inside the pipe along with the oil and deposited carbon becomes a fatal combination for explosion. Thus, only a rise in temperature above a certain limit or just a generation of a spark or hot spot can ignite or blow off the whole compressor.