Working principle and application of marine plate heat exchanger

Plate heat exchangers for ships, we call them marine heat exchangers, are mainly used in cruise ships, liquefied gas ships, container ships, bulk carriers and engineering ships. Its main working conditions include ship central cooling system (high and low temperature fresh water cooling), diesel engine cooling, preheating, cylinder liner cooling, lubricating oil cooling, heavy fuel oil preheating, seawater desalination, etc.

Ⅰ. Working principle of marine heat exchanger

The structure of the marine heat exchanger is the same as that of the general heat exchanger equipment. On the sheet of stainless steel, titanium and other corrosion-resistant metals, it is flattened and formed by a press with designed corrugations, and a synthetic rubber gasket is used around it. The sheet is sealed to form a "heat transfer plate". Suspend the required number of above-mentioned heat transfer plates from the guide rods, overlap between the steel plate fixed frame and the movable frame, and fix them with screws. The high-temperature fluid medium and the low-temperature fluid medium are separated by a piece and alternately flow in the flow paths formed between the plates for heat exchange.

Because it is an ocean-going operation, all equipment must ensure stability, and the marine heat exchanger has stable performance, long service life, easy installation, smaller footprint, higher heat exchange efficiency, and less fouling at the same time; in addition, it is special The use of titanium plates can prevent seawater from corroding the plates, prolong the service life, and save costs in the long run. In the shipping industry, the high efficiency, high quality, safety and reliability of marine plate heat exchangers play an important role in the normal operation of marine turbines.

Ⅱ. Application of marine heat exchanger

1. Cooling system, the central cooling system is divided into high temperature hot fresh water and low temperature warm fresh water closed system. The former is used to cool the main engine, and the latter is used to cool hot fresh water and various coolers. The heated fresh water is cooled by an open seawater system in a central cooler. Therefore, only one cooler using seawater as cooling fluid is used, which simplifies the arrangement of seawater piping. The seawater and freshwater pipelines in the central cooling system are separated, the freshwater pipelines are less corroded and clean, the management cost is low, and the system has strong reliability; the high-temperature and low-temperature freshwater channels respectively cool different ship equipment, which makes the system adaptable and improves equipment work. performance.

2. Propulsion system, including operating subsystems such as lubricating oil system, jacket water system (open and closed) and fuel system. All of these systems are heated when energy is generated and used for cooling using heat exchangers within the system to control the temperature. Through heat transfer, heat is transferred from the engine coolant to the ship's circulating water. In this way, the engine coolant can be kept in an appropriate temperature range to avoid damage to the engine caused by overheating and overcooling, and at the same time increase the working efficiency of the engine.

3. Fresh water system, in order to produce fresh water, seawater condenser and jacketed evaporator are used, both of which are types of heat exchangers. The low-temperature and low-pressure fresh water conducts heat transfer, so that the salt in the seawater can be condensed and separated, thereby realizing seawater desalination. In addition, heat recovery can also be realized, and the waste heat generated can be reused to increase energy utilization efficiency. Therefore, the application of marine heat exchangers in fresh water generators plays an important role in ensuring the safety of life at sea and navigation.