Current Situation and Development Trend of Fishing Vessel Refrigeration Technology

Shandong Friend Refrigeration & Air Conditioning Co., Ltd. is located in Shidao, Rongcheng, a coastal city with beautiful mountains and rivers. Current Situation and Development Trend of Refrigeration Technology "Certificate of Approval of Fishing Vessel Construction and Repair Factory", with the qualification of "Installing Refrigeration System of Various Fishing Vessels". It has the production qualification and capability of marine pressure vessels and marine refrigeration and air-conditioning products, and the refrigeration and air-conditioning products have passed the inspection and approval of CCS. The main products are refrigeration, air conditioning, ice making and other categories, which are widely used in various ships, especially fishing boats.

The developed fishing boat refrigeration equipment is favored by users and widely used due to its superior performance, reliable quality and long service life. The products have been sold to Southeast Asia, Africa, South America and other countries and all over China.

The company has professional and technical personnel and high-skilled workers such as ship engineering, refrigeration and air conditioning, machinery, and electricity, forming a strong team for product development and technological innovation; it has modern workshops and production equipment that produce first-class products, which ensures the high quality of products. high performance

The company has established a sound quality management system and has been operating effectively. The company regards reputation and product quality as its own life, and always adheres to the quality policy of "strive for excellence, excellence, thoughtful service, and high quality", and strives to provide customers with first-class products and services.

Shandong Rongcheng is located at the easternmost end of the Shandong Peninsula, where not only is the landscape beautiful, but also brings together the Yellow Sea Shipbuilding, Rongcheng Shipbuilding as the leader, Yuantong Shipbuilding, Baibuting Shipbuilding, Dayu Island Shipbuilding, East China Shipbuilding, Xinyang Shipbuilding , Shidao Donghai Shipbuilding, etc. are the backbone of a group of fishing boat manufacturing enterprises, which can be called ocean-going fishing boat construction bases. The fishing boats built by Rongcheng are widely favored due to their advantages of large drag force, large cabin capacity, large freezing capacity and high comprehensive economic benefits, and have spread all over the world in fishing grounds.

2. Development history of fishing vessel refrigeration technology:

With the changes of fishery production and fishery market, fishing vessel refrigeration technology has gone through several periods: Initial development period in the 1980s—represented by 8154, 8160, 8163 and other vessel types, generally equipped with two 810 series piston refrigeration compressors, 0.96 There are two aluminum alloy flat plate freezing machines per ton/time, with a daily freezing capacity of 8 tons. Depression period in the 1990s - during this period, the number of newly built refrigerated fishing boats was rare, and the supporting refrigeration equipment developed in the direction of miniaturization and simplification. The stable development period from 2000 to the present - after years of development, fishery enterprises have accumulated a certain amount of capital, and with the support of some policies, the number of newly built and renovated frozen fishing boats has increased rapidly, and the requirements for the freezing capacity of fishing boats and the quality of fish preservation are required. With the continuous improvement, the technical level of refrigeration equipment and the design level of refrigeration systems have been developed rapidly. During the stable development period, there are mainly HC837, HC867, RC879 and other representative ship types. Generally, it is equipped with two 812.5 series piston refrigeration compressors and two 4.2-ton/time aluminum alloy shelf blowing and freezing devices, with a daily freezing capacity of 24 tons. After 2010, these representative ship types were gradually changed to be equipped with one CYJZ-2X125A marine semi-hermetic screw compressor unit and two 4.8-ton/time aluminum alloy shelf blowing and freezing devices, with a daily freezing capacity of 30 tons.

3. Development status of fishing vessel refrigeration technology:

Freezers play an important role in fishing boats. Especially in ocean-going fishing boats, the performance and efficiency of freezing devices not only affect the fresh-keeping quality of the catches, but also directly affect the output of fishing boats, especially for fishing boats operating in resource-rich ocean-going fishing grounds, their production capacity is directly determined by their freezing processing capabilities. Decide.

The freezing processing capacity is mainly restricted by the technical performance of the refrigeration equipment. Traditional freezing devices have defects such as uneven liquid supply, slow freezing speed, and troublesome operation; aluminum alloy freezing devices have disadvantages such as rapid corrosion and short service life; traditional piston refrigeration compressors cannot meet the actual freezing capacity requirements; traditional ultra-low temperature refrigeration technology It has been in the system for decades, and has not been improved and developed. The economical operation of the refrigeration system is low; there are many unreasonable factors in the design of the refrigeration system of fishing boats, and some designs have great misunderstandings. These unfavorable factors not only seriously waste resources, increase manufacturing costs, and directly affect the economic benefits of fishing boats, but also seriously hinder the further promotion and application of refrigeration technology on fishing boats.

In response to these problems existing in traditional refrigeration technology, we have carried out some discussions and improvements, mainly in the following aspects: 1. Application of new technology to improve freezing device

There are three main types of traditional freezing devices: aluminum alloy flat plate freezing machine, aluminum alloy shelf blowing freezing device, and steel pipe shelf blowing freezing device

In view of the defects of uneven liquid supply, slow freezing speed, and troublesome operation of traditional freezing devices, pay attention to the use of products, research and discover the causes of existing problems in a timely manner, and apply a number of new technologies and proprietary technologies to make freezing The device has fast freezing speed, uniform temperature of frozen products, high quality of frozen products, stable and reliable work, and convenient operation. The freezing time of the improved aluminum alloy plate freezer has been shortened from 5-6 hours to 3.5 hours; the freezing time of the aluminum alloy shelf blowing freezing device has been shortened from the original 8-9 hours to 5-6 hours, and the freezing efficiency has been increased by 50%. % or more; the thermal expansion valve is used to automatically supply liquid to ensure the stability and reliability of the entire freezing process.

Aiming at the problems of rapid corrosion and short service life of the aluminum alloy freezing device plate, the surface of the aluminum alloy plate is strengthened with a process to make it resistant to friction and corrosion; using a unique welding process, the welding seam is bright and beautiful, and the corrosion resistance is strong, which is consistent with the Other products on the market are quite different. The aluminum alloy freezing device we installed in 2000 is still in normal use, and there is no problem of flat plate corrosion.

For more than ten years, the refrigeration equipment and refrigeration systems we have installed on the ship have been tested for many years, which proves that they have high performance, few failures, and convenient operation and management. Love and great support. All users who have used our products and those who know about our products will name and request our company's products or the refrigeration system matching and installation by our company when they build new fishing boats or renovate fishing boats. In recent years, our company has more than 200 fishing boats supporting or installing refrigeration equipment every year.

2. Application of semi-hermetic screw refrigeration compressor

With the development of ocean-going ships, the original piston compressors cannot meet the new requirements in terms of cooling capacity and cooling efficiency. In 2010, we began to research and develop marine screw compressor units, using semi-hermetic screw compressors of BITZER and other brands to assemble them into units suitable for marine use. This unit has a compact structure, takes up little space in the engine room, has a large cooling capacity, and has a strong overload capacity, which is especially suitable for large freezing capacity requirements; because it can work in a higher evaporating temperature range, the cooling coefficient is large, the cooling efficiency is significantly improved, and the energy saving effect is remarkable; Fewer moving parts, low maintenance cost; easy operation, high reliability and long service life.

Application of semi-hermetic screw compressors: In 2011, 8 sets of ships were used; in 2012, 16 sets of ships were used; in 2013, 65 sets of ships were used. At present, it is also widely used in multi-type large-scale ocean-going trawlers, ocean-going squid fishing boats, and light-covered net fishing boats.

3. New ultra-low temperature refrigeration scheme

The traditional tuna fishing boat ultra-low temperature refrigeration system generally uses an open piston refrigeration compressor with R22 as the refrigerant. After decades of practical application, the refrigeration compressor has high reliability and long service life, and can meet the requirements of refrigeration below -50 ℃ Temperature requirements (evaporation temperature -60 ℃). However, when this refrigeration compressor uses R22 refrigerant, the evaporating temperature of -60°C is close to its working limit, and it is difficult to reduce the evaporating temperature or the cabin temperature; in addition, when working at this evaporating temperature, the refrigeration coefficient of the refrigeration compressor is relatively high. Low, that is, the same compressor has a smaller cooling capacity and a long working time, resulting in a lower economy of the entire refrigeration system.

In view of the above situation, we have researched and developed a new ultra-low temperature refrigeration scheme. The ultra-low temperature refrigeration system using semi-hermetic refrigeration compressors of BITZER and other brands and R404A as the refrigerant is a new ultra-low temperature refrigeration scheme that effectively applies the advantages of modern technology, which can overcome the above-mentioned traditional ultra-low temperature refrigeration schemes with low refrigeration coefficient and poor operating economy. weakness. First of all, when the refrigeration compressor uses R404A refrigerant, the evaporation temperature in the permitted working range can reach -70°C, and it is very easy to reach the cabin temperature of -50°C~-60°C; it also works under the evaporation temperature condition of -60°C, Its refrigeration coefficient is increased by more than 40% compared with the use of R22 refrigerant; again, multiple compressors can be used to form a parallel unit, and the number of refrigeration compressors can be determined according to the needs of different working conditions, and at least one compressor (motor) can be turned on. Power 22KW), can save energy consumption;

BITZER semi-hermetic refrigeration compressors are of good quality, stable and reliable operation, and have a long service life. Due to the semi-hermetic structure, the disadvantages of shaft seal leakage are avoided; due to the high intermediate pressure of the crankcase, the operating oil under ultra-low temperature conditions is guaranteed. Stable and reliable pressure.

Application cases of new ultra-low temperature refrigeration solutions:

1. In 2009, the MC8302 39.8m tuna fishing boat was designed and equipped with a new type of ultra-low temperature freezing device, using 4 sets of S6F-30.2Y semi-hermetic refrigeration compressors and R404A refrigerant. This type of ship (Zhongrong 13 and Zhongrong 15, a total of 2) was delivered for trial delivery in January 2010, and went to Fiji fishing grounds in April. After nearly four years of operation, it has been proved that the effect of the refrigeration unit is very satisfactory, the freezing quality of tuna has been highly praised by customers, and it has obtained a good price; the average fuel consumption of the ship is about 800KG/day, and it has achieved good economic benefits.

2. In 2011, the WJY8028 42.8-meter tuna fishing boat was designed and equipped with a new type of ultra-low temperature freezing device, and 6 sets of S6F-30.2Y semi-hermetic refrigeration compressors were selected in parallel, and R404A refrigerant was used. The parallel unit is designed to cooperate with the refrigeration system and is divided into an ultra-low temperature system and a normal temperature system. The two systems work at different evaporation temperatures, which not only meets the requirements of different working conditions, but also maximizes the refrigeration coefficient of the refrigeration compressor. Improve the economics of refrigeration systems. If the ship is equipped with three ultra-low temperature refrigerated compartments, in the early stage of each voyage, the rear can be refrigerated.

The tank is incorporated into the ultra-low temperature (evaporation temperature -60°C) system to keep the cabin temperature below -50°C for storing ultra-low temperature fish; while the front refrigerated compartment is incorporated into the normal temperature (evaporation temperature -45°C) system to maintain - The cabin temperature of 35°C is used to store bait or ordinary temperature fish. At the end of each voyage, the front refrigerated compartment can also be incorporated into the ultra-low temperature system to meet the requirements of ultra-low temperature refrigeration

There are 4 freezing devices, each of which can be incorporated into the ultra-low temperature system or into the normal temperature system. Fresh fish can be frozen first in the room temperature system freezing device to maintain a high refrigeration efficiency. When the temperature drops below -35°C, the frozen fish will be transferred to the ultra-low temperature system freezing device for further freezing, ensuring a lower temperature. Freezing temperature and better freezing quality.

This type of ship (Rong Dayang 16, Rong Dayang 17 and Hongyang 8, Hongyang 9 total 4 ships) went to Fiji fishing grounds in July and August 2011 respectively. After nearly three years of operation, it has been proved that the refrigeration unit operates stably and reliably, and the average fuel consumption of the ship is less than 1000KG/day. The average fuel consumption of similar ships using the traditional ultra-low temperature refrigeration scheme is 1300~1400KG/day.

Since 2010, a total of 61 new ultra-low temperature refrigeration units have been installed for tuna fishing boats, including 2 in 2010, 8 in 2011, 17 in 2012, and 34 in 2013. Better results and better economic benefits.

The technical and economic advantages of the new ultra-low temperature refrigeration scheme are very obvious. After the actual test results of multi-type ships, the ultra-low temperature refrigerated cabin has a fast cooling speed and a short freezing time; the use of the new ultra-low temperature refrigeration scheme for the same type of tuna fishing boat can save more than 40% of fuel compared with the traditional ultra-low temperature refrigeration scheme. All users who have used the new ultra-low temperature refrigeration scheme have given high evaluation and obtained good economic benefits. It is estimated that only by saving fuel consumption, each ship can increase economic benefits by about 1 million yuan per year. In addition, the benefits of raising prices due to the good quality of fish are also considerable. The new ultra-low temperature refrigeration solution is more and more recognized and accepted by more shipowners, and it also creates more value for more shipowners.

4. Problems and solutions in refrigeration system design

With the development of pelagic fisheries, the demand for pelagic fishing vessels has increased, and the requirements for the refrigeration technology of fishing vessels have been continuously improved. Relevant ship design institutes and refrigeration equipment supporting enterprises have conducted some discussions on the refrigeration technology of fishing boats. Some discussions have played a role in promoting the improvement of refrigeration technology for fishing vessels, while others have not played a role in promoting, and even entered some misunderstandings. According to our investigation and understanding, we believe that there are still the following problems in the application of refrigeration technology for fishing vessels:

1) Some freezing device products have defects such as low technical content, slow freezing speed, and low quality of frozen products; the aluminum alloy plate begins to corrode at an early stage, causing refrigerant leakage and affecting the normal operation of fishing boats. Therefore, some ship owners dare not use aluminum alloy refrigeration and freezing equipment.

2) There is a misunderstanding in the design of the refrigeration system of the fishing boat. In some cases, the thermal expansion valve used for freezing equipment has problems such as uneven liquid supply, slow freezing speed, and easy liquid return. In order to improve the freezing efficiency, a low-pressure circulating barrel is used instead.

Fluorine pump liquid supply scheme; some in order to achieve automatic operation, the design of the refrigeration system is too complicated. These designs not only greatly increase the cost, but also increase the difficulty of operation and maintenance.

The low-pressure circulating barrel plus pump liquid supply scheme is suitable for ammonia refrigeration systems and is used in fluorine refrigeration systems. Due to the characteristics of Freon refrigerants, the lubricating oil and refrigerant are in a mutually dissolving state, and it is difficult to separate them in the low-pressure circulating barrel, even if some measures are taken. It is also difficult to recover lubricating oil normally, which in turn affects the cooling effect. There are many cases where applications have to be removed after a while.

3) There are other problems in the design and installation of the refrigeration system. In response to these problems, I once published the article "Several Issues Concerning the Refrigeration System of Fishing Vessels" in the fourth issue of "Fishery Machinery and Instruments" in 1994. Now it seems that this article has practical significance.

China's fishing vessel refrigeration technology has developed rapidly after several generations of continuous research, exploration and innovation. Especially after the stable development period from 2000 to the present, a number of excellent refrigeration equipment manufacturing and supporting enterprises have emerged, and a series of products with high technical level, excellent performance, stable and reliable quality have been launched, which have well met the needs of frozen fishing boats. Promote the development of distant water fisheries.

Looking back on the development and application of fishing vessel refrigeration technology, I deeply realize the contribution of private enterprises, especially private fishery enterprises, to the advancement of fishing vessel refrigeration technology. They have the guts and courage to be the first to eat crabs; they focus on practical results and value practical benefits. Many new technologies and new equipment are often first tested and applied in private fishing boats, and can be quickly promoted in private fishing boats. Because of their bold application, it has promoted the progress of refrigeration technology for fishing boats.

Fourth, the development trend of fishing vessel refrigeration technology:

The development of fishing vessel refrigeration technology is inseparable from the actual needs of fishing vessels and the needs of fishery development. As the departments and enterprises supporting the research of refrigeration technology for fishing vessels and the production of refrigeration equipment, not only must they be able to meet the actual needs, but they should also be closely linked with the application practice, and explore and research the products that are more suitable for the development of fishery, especially for ocean fishing.

New technologies and new equipment for the development of the industry. To this end, we believe that exploration should be strengthened from the following points:

1 Strengthen the scientificity and practicability of refrigeration system design, and maximize the economy and reliability of refrigeration system operation.

2 Explore technologies and complete sets of equipment for direct and refined processing of fish catches on fishing boats with frozen processing as the core. Make full use of the advantages of high freshness of the fish on board, maximize the quality and value of processed products of the fish, and improve the economic benefits of fishing boats.

3. Strengthen the complete set, modularization and standardization of refrigeration equipment, and improve the quality and reliability of refrigeration equipment.

Conclusion:

We believe that: at present, China has the world's first-class fishing vessel refrigeration technology and products, and has the ability to compete in the world's fishing vessel refrigeration equipment market. We hope to provide high-quality refrigeration equipment and advanced refrigeration technology services for more fishing boats, and make due contributions to the development of my country's fishery economy; contribute to progress.