- They are hard, abrasive particles.
- It is also possible to contaminate a clean marine residual fuel oil with catalyst particles during transport. For example, if steamship fuel (frequently containing catalyst particles) has been transported by barge prior to moving a clean heavy fuel oil for a diesel powered ship, the barge bottom sediment will be mixed with the clean fuel oil and will contaminate it.
- Cat-fines are generally small, very hard, and quite abrasive to pumps, atomizers, piston rings and liners.
- (30 ppm) of alumina in the bunkered fuel oil is the upper limit for successful treatment and engine operation.
- The average particle size, as well as the concentration, greatly impacts the wear rate of engine components.
- Small sized catalyst particles (1-10) micron range typically cause accelerated wear in injection pumps and injectors and only moderate increases in cylinder assembly wear, such as piston rings, piston grooves, and liners.
- The larger sized catalyst particles, in the ten to seventy (10-70) micron range, typically causes very accelerated wear rates in the cylinder assembly area. Also on injection pump inlet valves, exhaust valve seating areas, and turbocharger turbine blading.
Any opening in a pressure vessel is kept to a minimum and for a man entry an elliptical hole is lesser in size than the corresponding circular hole. More over it is prime concern to have a smoothed generous radius at the corners to eliminate stress concentration. Hence other geometrical shapes like rectangle and square are ruled out. To compensate for the loss of material in the shell due to opening, a doubler ring has to be provided around the opening. The thickness of the ring depends on the axis length along the dirrection in which the stresses are maximum and the thickness of the shell. It is important to align the minor axis along the length of the vessel, as the stress in this direction is maximum. Longitudinal stress: Pd/2t where P= pressure inside the vessel, d= diameter of the arc, t= thickness of the shell plating Circumferential stress: Pd/4t More over a considerable material and weight saving is achieved as minor is along the direction of maximum stress.