Introduction of Plate Heat Exchanger in Marine Turbine
In marine turbine, the heat exchange is undoubtedly a very critical factor to ensure the normal use of the engine. Because when the turbine is working, it needs to maintain a certain temperature to ensure the normal operation of the machine. There are many kinds of heat exchangers used in marine engine, in which plate heat exchanger is one of the very important one, and will be the very popular potential equipment on vessels in the future.
The heat exchanger has been one of the indispensable equipments in marine engine, which can be applied in the main and auxiliary oil cooler, cylinder liner fresh water cooler, fuel heater, steam condensers, water heater and other equipments. The special working environment of the ship has very special demanding on the heat exchanger, including the factors such as instability in the sea, which may encounter vibration, shock, large angle tilt and noise. The cooling medium is usually seawater, which is with high salt concentration, high humidity of the working environment, and very strong corrosion of the plate. The marine itself is very compact in structure, having more stringent restrictions on the heat exchanger space and quality. The heat transfer medium of traditional heat exchanger is always water, and the heat transfer medium of marine heat exchangers is generally oil and water and so on. The emergence of plate heat exchanger effectively solves a large part of the problem.
1. The equipments for vessel requires compact structure and small quality.
At present the plate heat exchanger, used in the ship turbine is generally considered smaller than the traditional heat exchanger, with very small volume. For this purpose, finite element analysis is used. At the same time, in order to meet the requirements of marine equipments, the unnecessary parts of the plate are removed or reduced according to the actual stress and strain distribution, and the weak parts are locally thickened. Put gas cutting method on the whole body to reduce the influence of welding deformation on the strength, and weld together the inner plate and the panel, then eliminate the residual stress. It will be able to make the use of equipment as much as possible on the installation in limited space, to bring more benefits; it will complete the heat transfer work to ensure the normal use of the marine.
2. The equipments for vessel must be for the impact power, large angle shaking, vibration and other issues.
Using multi-point fixed method on the bottom of the board, that is, all fixed parts can be used fixed connection. Some important special parts also use a rib structure, which increases the stability of the equipment. Only when the installation stability is improved, the heat exchange efficiency and effect of the heat exchanger can be ensured. It will affect the heat transfer effect, once it occurs due to problems such as vibration,
3. The problem that the cooling medium is seawater and the concentration of nitrogen ions is high
Since many turbines are in direct contact with seawater, they have a very large effect on the heat transfer medium during use. Therefore, at present, the plate used in the turbine is usually made of a material with high corrosion resistance, such as titanium material, and its quality is much smaller than that of stainless steel. In order to ensure the quality of the titanium plate, in addition to the routine inspection, the plate is also subjected to 100% color penetration test to further eliminate the error when the board is sampled.
4. Heat transfer media problems
Since the specific heat capacity difference between water and oil is relatively large, the temperature difference is larger during the heat transfer process, and the heat transfer coefficient is also larger. In order to make the product reliable and economical, it is necessary to ensure the oil-water heat transfer performance under the ship working conditions to ensure that the equipment has a certain heat exchange margin. Only when the heat medium can effectively conduct heat, can the heat transfer effect be achieved.
5. Low price and operability
Plate heat exchangers are inexpensive and its production process is very mature. During production or maintenance, we can reduce costs and increase efficiency as much as possible. It can be cleaned by loosening the screws in the mounting structure and reassemble to use again. If it is already damaged, then we can just change a new one. Its low price enables it be prepared in emergency equipment.