Offshore fishing is one of the important directions in the development of the fisheries sector in Vietnam. Although the fisheries productivity is high, the loss after exploitation is high. According to the Directorate of Fisheries, losses after fishing in Vietnam account for 20-30% of the productivity, mainly due to the fact that a majority of fishing vessels are of small capacity, with lack of preservation devices and fisheries mainly preserved by ground ice. Therefore, reducing post-harvest losses, despite difficulty, has been identified as a top priority for the fisheries sector.
One of the proposed solutions is the application of snow ice making technology, in which mastering technology of designing and manufacturing snow ice making machines will provide an important foundation for the application of snowmaking technology in seafood preservation in offshore fishing in Vietnam.
The Center for High Technology Development under the Vietnam Academy of Science and Technology (VAST) has studied and manufactured a machine producing snow ice from sea water based on the results of a VAST level scientific and technological task “Research on machines manufacturing snow ice from sea water to serve offshore fishing fishieries preservation” by MSc. Le Van Luan, code VAST.CTG.13/16 -17.
On April 27, 2018, the work was tested and ranked excellent by VAST Testing Council.
Machine produces snow ice from sea water
Snow ice room structure
This is the first product produced domestically, from research, manufacturing and testing on fishing boats. The producer has mastered the technology of making ice snow room, including: funnels, rockers, water sprinklers, cold water circuits, heat exchangers using a single compressor system which operates stably and suitably with Vietnamese fishing vessels. In order to increase the heat exchanger efficiency of the snow ice room, the traditional twisted heat exchanger is replaced by a casting technology.
Product creation: The snow ice maker incorporates a central controller with functions to protect and monitor system performance, to increase stability and extend the life of the device, including: overload protection, protection of high pressure, low pressure, detection of water level. Users can easily select and adjust the snow ice concentration of between 25% to 95%, or at a certain temperature. When the system starts, devices, motors are switched off at different time intervals to reduce the system startupcurrent. In particular, the compressor is started by a soft start method for the smallest start current.
High stability and competitiveness: snow ice machines are made from materials that are resistant to corrosion of sea water such as: 316 stainless steel and PVC plastic. Compressors, oil separators, condensers and other equipment are used exclusively for ships, ensuring durability and reliability. Additionally, in order to increase stability, balancing and oil compensating units in the conditions of working in the sea fluctuation conditions will be studied and integrated into the product in the coming time. Mastering the production technology, the product produced by the Center for High-tech Development is sold at competitive price on the market.
Apart from this, the Center for High-tech Development’s snow ice maker also contributes to minimizing the impact on the environment, efficiently exploiting resources, and bringing greater economic efficiency by increasing quality, prolonging storage time of fish on board due to lower storage temperature than ice made from fresh water; reducing the number of laborers freezing fish as the fish can be immediately stored in ice. The distribution and delivery of ice to the storage compartments is simplified by using direct pumps. Vessel owners will save space on board as it is not necessary to have ice compartment when snow ice is made directly from sea water. Direct cost caused by ice loss, ice transport from the mainland will be reduced, while the quality of preserved fisheries will be increased.
The product has been tested for a long time at the workshop of Mechanics - Electronics of the Center for High Technology Development and also tested in reality at seaports and on fishing ships in Hai Phong waters. The evaluation by scientists, testing units and fishing vessels’ owners show that the product runs stably and meets the requirements.
The product has a capacity of 1,250kg every 24 hours. However, each voyage needs some 50-60 tons of ice, it is necessary to have machines with greater capacity, equivalent to some 5 tons every 24 hours. Therefore, scientists at the Center for High Technology Development under the Vietnam Academy of Science and Technology are continuing to perform a state-level scientific task to study and produce snow ice machines with a capacity of up to 10 tons every 24 hours, along with the analysis and development of a process for the preliminary processing and preservation of high quality tuna by snow ice, to improve the quality of tuna, meeting export standards into the markets.
Translated by Phuong Huyen
Link to Vietnamese version