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25.05 10:19 - There are several different methods of ballast healing
Автор: bluesky123 Категория: Други   
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There are several different methods of ballast healing offered by system manufacturers. Some are more matched to different ship types than others as well as some more suited to the operating profile of the ship. Both these considerations in conjunction with type-approval status and of course cost and availability needs to be factors taken account regarding when choosing.

Before investigating the system technology itself it is worth considering the dilemma of filtration. Most of the systems out there have a filter included factored in the system but some never. There will be a diploma of filtration provided by strainers at the ballast intake but which is to protect the sends and prevent piping blockages and not considered in the treatment.

The cause of filters being used is usually to assist in meeting the IMO’s D2 discharge normal which requires that cared for ballast must contain:

fewer than ten viable organisms more than or equal to FIFTY micrometres in minimum element per cubic metre;
less than ten viable organisms below 50 micrometres in minimum dimension and higher than or equal to TWELVE micrometres in minimum measurement per millilitre.
It stands to motive that if such organisms could possibly be removed by filtration at the outset then meeting the discharge standard is only problematic due to more compact organisms growing whilst held inside ballast tanks.

Filtration also removes sediments that may both diminish the healing efficacy (especially in UV systems) and cause build-up in the ballast tanks which adds needless more weight to the ship and which will also provide ideal conditions for organisms to reside and grow.

On this negative side, filters enhance the expense of the method and need regular backflushing to stop blockages and thus slow-moving the intake of ballast. Another argument that is created against filters is the very small mesh dimension of 50 micrometres or less can readily be enlarged over time from the action of sediment and will thus eventually become inadequate. The microscopic mesh size would make these degradation almost impossible for you to detect by sight.

A small amount of systems employ hydrocyclone technology because the method of removing bigger solids. In these systems, the water is pumped to your specially shaped chamber where a vortex is induced through the flow. Sediment and some organisms shall be channelled away from the water which continues on its approach to the next treatment stage.

The topic of filters has grown something of a battleground using makers of filtered models and makers of full-flow models each arguing in favour health of their chosen options. In most cases where filtration must be used, its presence will have been part of the type-approval practice, therefore specifying such a system minus the filter would not become acceptable and would place the ship in danger of falling foul of your PSC inspection. If an owner decided that filtration is desirable but the system isn"t going to rely on a filter, it would be likely to add one before treatment stage but this may negatively affect the performance with the system and may invalidate any kind of warranties.

After filtration any of several methods may be employed. Mechanical processes are tested only into the G8 rules as are most UV systems however oxidation including electrochlorination and many other methods must furthermore undergo approval for ingredients under the G9 course of action.

Cavitation/Ultrasound
Systems employing cavitation do not generally rely on it as the sole treatment method but as an approach of making subsequent treatments far better. Cavitation can be induced by injection of gas or liquids or by altering the contour of the ballast piping over a region of the flow. The forces brought on by the cavitation act about organisms damaging or killing them dependant on their robustness. Ultrasound should be used as another means of inflicting shock trouble for organisms and can often be independently generated or induced from the piping profile.

Heat
These systems use the waste heat in the ship’s engines and the heat exchanger to raise the temperature in the ballast water to ranges sufficient to kill organisms. A single the ballast is continuously treated and used as being the source of cooling water to the engine. The heat extracted through the engine treats the ballast when using the water then passing through a second heat exchanger to provide hot water or heavy steam to either be employed directly in other ship systems or as part of a waste heat recuperation system.

An early objection to heat was that large temperatures in ballast tanks could possibly have a detrimental effect in some cargoes however heat ballast to lower temperatures may improve the effectiveness of some chemical treatments and also the heat can then be removed having a second heat exchanger.

Deoxygenation
These systems function by removing oxygen from the ballast water by venturi stripping or adding inert un wanted gas in sufficient quantities to bring the oxygen content below that had to support life. Deoxygenation is often combined with another means of disinfection or used with a stand-alone basis. On some tankers wherever generation of inert gases has already been carried out, the same equipment might be able to be used for getting rid of the ballast flow. Deoxygenation is claimed to get a secondary benefit for the reason that it will limit corrosion within the ballast system. There is some question as to whether lack of oxygen is injurious for some life stages of particular organisms.
https://www.qlozone.com/Ozone-Water-Systems-pl3966265.html 201911ld



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Автор: bluesky123
Категория: Други
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