Research Basics in Use. Texts "In the air conditioner", "Dehumidification systems within shipbuilding industry", страница 6

2. Text

Dehumidification systems within shipbuilding industry

The problem

In spite of the fact that ships are in water, water is a great problem. Munters Company deals with the problem of condensation. When a ship sweats, moisture condenses on its interior surfaces. Hulls rust, paint blisters, wiring and electronic circuits malfunction. Cans rust, produce rots and mildews, cartons get soggy and labels get stained. Liquid cargo becomes contaminated. Sandblasting and painting must be rescheduled or redone. The result is millions of dollars lost every year. And even more revenue is lost while ships sit idle for unnecessary repairs.

The solution

However condensation is a problem that can be solved, Munters has the solution. Condensation is prevented when the dew point temperature in the hold or tank is kept lower than that of the ship’s structure and cargo temperature. In any case, a Munters dehumidifier will maintain a required dew point level, regardless of outside weather conditions or extreme temperature changes. All Munters dehumidifiers are designed on the principle, which uses a slowly revolving wheel, impregnated with desiccant, to draw moisture from air. As air moves through the wheel, it is dried and returned at a safe dew point level.

Although the dehumidification principle remains the same, each type of vessel, tank or container has its own unique and individual requirements. Munters offers a complete line of dehumidifiers, and control equipment, or systems specifically designed to meet the needs of differing situations.

Inert gas systems

On the other hand, one of the newest projects that Munters participating in is the inert gas system on LNG ships carrying cargo at –127⁰C. Munters dehumidifier is an integral part of this system. Dry inert gas used to fill LNG tanks prevents the formation of a flammable atmosphere and ice build-up inside the LBG tanks. In a nutshell, this is how the system works: Gas from an inert gas generator is routed through a gas scrubber, which cools it and removes solid particles and acidic components from the gas. This is where Munters comes in. A Munters dehumidifier then dries the gas, which has become saturated in the scrubber, and lowers the dew point. This low-oxygen controlled-dew point gas, which will not support combustion, and prevents ice build-up, is piped to the tanks.

3. Talk on the problems (disadvantages, shortcomings, drawbacks) of your project.

D. Result

1. Study this:

2. Text.

Dehumidification

The relative humidity in painting is usually too high and there are different ways to lower it.

Thus a straight method is to decrease the moisture content of the air by dehumidification. At anti-corrosive painting, the method of sorption dehumidification is used, involving that a hygroscopic agent absorbs the moisture out of the air. For this reason, this method is equally good at all temperatures. One usually dehumidifies to a relative humidity of 35-50% RH, which is rust-preventing. At dehumidification, some kind of shielding to the open is necessary. Because of insufficient hightness it will do with awnings or a plastic foil on a bolt arrangement. In closed premises and indoors the entire volume is dehumidified.

The dehumidifier is based on Munters’ sorption rotor. It is divided into two zones, a working zone where the rotor absorbs moisture from the process air, and a reactivation zone where hot reactivation air absorbs moisture from the rotor. The rotor is turning slowly, about 10 r/h. The dehumidification and reactivation is continuous. Therefore the dehumidifier operates without problems also at temperatures below zero.

3. Talk on the results (planned or obtained) of your research.