Build a "marine ranch" on land to see how LNG stations "raise" seafood

A "marine ranch" is built on land, and cold energy can be recycled——

See how LNG stations “raise” seafood

　　Our reporter Li Jie

　　Not long ago, the country's first LNG cold energy breeding demonstration project was officially launched at the CNOOC Guangdong Dapeng Liquefied Natural Gas (LNG) receiving station. The growth and physiological indicators of a batch of high economic value seafood have been stable during the trial breeding observation period, and some have already ushered in the period when their meat quality is the most delicious.

　　How are liquefied natural gas and seafood, seemingly completely unrelated things, related? What are the benefits? A few days ago, reporters went to CNOOC Guangdong Dapeng LNG receiving station for an on-site visit and saw the green ideas and technological strength behind cold energy farming.

“I have been raising fish for more than 30 years, and this is the first time I have done so in an LNG receiving station.”

　　On a winter afternoon when I visited, the sun was shining warmly. Located in Dapeng Bay in the east of Shenzhen, the clear water ripples with the wind, bringing the moist atmosphere of the ocean. The Dapeng LNG receiving station is located on the shore of Dapeng Bay. Since the receiving station receives liquefied natural gas shipped by LNG ships, it is basically built on the seaside.

　　Entering the factory, bypassing the liquefied natural gas storage tanks and crisscrossed pipelines, you can see only a canal of rushing sea water, with two neatly arranged blue water tanks on the upper and lower floors connected at the end. This is the protagonist of this visit, "seafood" where.

　　Lao Fan is the staff member responsible for breeding here and is feeding these "babies" in the water. The lobsters are growing well, the spotted snappers have survived the recent low temperature weather, and the abalones have to grow several times in size... Lao Fan took the net bag and introduced the progress while checking. "I have been raising fish for more than 30 years, and this is the first time I have been in an LNG receiving station." Lao Fan said that the good water and low temperature here are especially rare.

　　When I dipped my finger in it, the water was indeed quite cold. The thermometer next to the water tank shows a temperature of 15 degrees Celsius. Why you want to raise fish in an LNG receiving station starts with the water temperature.

　　The temperature of the liquefied natural gas in the LNG storage tank is as low as minus 162 degrees Celsius. After arriving at the receiving station, it must be heated to restore the gaseous state before being transported to thousands of households. The gasification process will generate a large amount of cold energy. How to comprehensively utilize cold energy is an important issue.

　　"In other words, the receiving station is like a 'big cold storage'." Niu Junfeng, senior manager of energy technology of Guangdong Dapeng LNG Co., Ltd. introduced that in 2023, the cold energy processing capacity of the Dapeng receiving station will exceed 8 million tons. If it is converted at 100% It is estimated that it is equivalent to more than one billion kilowatt-hours of electrical energy. It would be a pity not to utilize it.

　　how to use? Seafood farming is one of those ingenious ideas. Originally, a large amount of seawater was used in the gasification process of LNG. After the seawater is filtered, it enters the receiving station system for heat exchange with liquefied natural gas, and then forms low-temperature seawater that is very scarce in the south. In layman's terms, this process is like using hot water to heat a glass of cold milk. As the milk heats up, the water temperature will decrease.

　　"After heat exchange between liquefied natural gas and seawater, the seawater temperature will drop by about 5 degrees Celsius, and it will generally remain between 15 and 25 degrees Celsius depending on the season, which is very suitable for the growth of fish with high economic value." said Hao Yunfeng, president of Guangdong Dapeng LNG Co., Ltd. .

　　The staff on the project told reporters that the idea of ​​cold energy fish farming has actually been around for a long time. Today, the Dapeng receiving station has been in stable operation for nearly 18 years. The main business of natural gas supply is strongly guaranteed, and the relevant conditions are mature, making cold energy fish farming finally a reality.

Let seafood "live" in air-conditioned rooms and "get on" treadmills, and the overall cost will be reduced by 30%

　　Cold energy is only one of the basic conditions. How to raise seafood? Can you adapt to the environment? There's a lot of solid work behind it.

　　Niu Junfeng told reporters that water quality and water temperature are two key factors that need to be considered in the project.

　　How is the water quality? According to reports, the project has carried out strict water quality testing on a regular basis since the feasibility study began. The water quality in the sea area where the Dapeng receiving station is located is excellent, and the seawater is filtered and electrolyzed multiple times to produce trace amounts of sodium hypochlorite for disinfection before entering the process system. The seawater produced is low-temperature, sterile, and has strong oxygen-dissolving capacity. It is a rare natural high-quality low-temperature breeding water. .

　　"For seafood grown in low-temperature seawater at the Dapeng receiving station, there is no need to add any fish medicine or other additives, which can ensure the high quality of the seafood." Cao Yueming, secretary-general of the Seed Industry Branch of the Shenzhen Aquaculture Industry Association, said that the fish used in the breeding project The cold water is flowing water, and the fish can maintain a good active state. It can be called a "fish on a treadmill."

　　How to keep water temperature stable? "In the design stage, we calculated and matched the cooling capacity required for breeding, and through a large number of breeding process simulations, we selected the optimal cooling process." Niu Junfeng said, considering the impact of high economic value cold-water fish on water temperature Sensitivity, the project team also developed a water temperature control system based on liquefied natural gas cold energy, which is like letting seafood "live" in an air-conditioned room and feel comfortable.

　　"In addition, LNG receiving stations have successful experience in marine aquaculture in the industry." Liang Qiang, chief engineer of Guangdong Dapeng Liquefied Natural Gas Co., Ltd., told reporters that in the end the company made up its mind and believed that this project was worth doing. This is not only considering the favorable conditions such as cold energy, water quality, and temperature control, but also considering that the breeding environment in the station is relatively closed and controllable. It can test the adaptability of different seafood species, which is very meaningful for future expansion and providing reference for peers.

　　From the determination of the cold energy breeding idea in December 2022, to the implementation of the design drawings in July 2023, the start of on-site construction in October, and the trial operation in November... the project is advancing rapidly. In Niu Junfeng's impression, "Such progress is rare in the entire company."

　　On December 2, 2023, the first batch of fry was put into the water. No matter how solid the preliminary work is, there are still many "unexpected things" in the process. For example, these seafood are sensitive to water temperature. High temperature will not work, nor will the temperature be too low. In just over a month, the local area has experienced two cold waves, but experience is accumulated bit by bit in practice. In the end, during the 40-day trial breeding observation period, the growth and physiological indicators of the red fish and snapper species released in the project were stable and they have fully adapted to the breeding water environment.

　　Cao Yueming said that the market price of this batch of seafood is more than 100 yuan per catty, and the overall cost can be reduced by 30% through cold energy breeding.

Ecology and economy are both cost-effective, and the comprehensive utilization of cold energy has broad prospects.

　　Where does the seafood produced go? Can consumers buy it?

　　According to reports, the first batch of "Dapeng" seafood is expected to hit the market in March and April this year. At present, relevant aspects of the project are carrying out testing, license application and other work to prepare for the listing. The demonstration project is expected to produce an annual output of 100,000 kilograms.

　　But on-site farming is far from the goal of this project. Liang Qiang told reporters that the 180 acres of low-temperature sea outside the receiving station already has relevant breeding conditions. As long as the pilot project of the demonstration project matures, it can go further overseas and expand its scale. "The output value by then will be measured in hundreds of millions of yuan."

　　"According to the plan, the demonstration project will run for at least one year and undergo different tests such as the coldest and hottest seasons before it is considered to be pushed to the sea," Niu Junfeng said.

　　In fact, the seafood breeding project is only part of the comprehensive utilization of cold energy at the Dapeng receiving station. At the same time, cold energy power generation, cold energy ice making and other projects are being continuously explored and advanced. Taking cold energy ice production as an example, Niu Junfeng said that Shenzhen uses a large amount of ice every day in both winter and summer. In large seafood markets, cold chain transportation and other places, ice is in short supply. However, traditional freezers consume a lot of electricity to make ice. This is where the "big cold storage" of the receiving station can take advantage. If edible ice is made, the added value is even higher.

　　As the earliest LNG receiving station in mainland China, the Dapeng receiving station has taken the comprehensive utilization of cold energy into consideration since the beginning of the project. "This original intention has always been there. We pay close attention to the latest advances in technology, and as long as there are good projects, we are willing to try them." Liang Qiang said.

　　How to calculate the accounts of the cold energy breeding demonstration project?

　　Looking at the economic benefits, Dapeng Company can basically achieve a balance between its investment and income in the project, while the partner breeding company can greatly reduce the overall cost and become more competitive in the market. Looking at the ecological benefits, it is estimated that reducing the temperature of 1 cubic meter of seawater by 5 degrees consumes 5.8 kilowatt-hours of energy. The cold energy used by the breeding project is equivalent to saving 1.97 million kilowatt-hours of electricity and reducing 1,800 tons of carbon dioxide emissions for society every year, which is approximately The environmental benefits of planting 1,800 trees a year are a typical green, circular, and low-carbon economy.

　　According to CNOOC, in the future, the company will continue to rely on its advantages in cold energy resources to further explore new technologies such as LNG cold chain logistics, cold storage, and cascade utilization of cold energy, so as to develop new application scenarios for the comprehensive utilization of LNG cold energy.

　　No, a new feasibility study report on the Dapeng LNG cold energy ice-making project is about to be released. The staff working on the project imagines that in the future, "Dapeng Ice" and "Dapeng Fish" will serve the Chinese people a plate of delicious sashimi. (People's Daily Overseas Edition)