The evaluation system for intelligent recycling of cold energy from LNG vessels

Through the study of LNG ship cold energy intelligent recycling technology, the analysis of ship propulsion efficiency improvement and LNG cold energy residual energy intelligent recycling is carried out to explore and solve the technical problems of imperfect cold energy recycling in LNG ship cold energy intelligent recycling technology. LNG ship cold energy intelligent recycling uses the combination of dual-fuel propulsion technology and LNG cold energy residual energy recycling technology. The LNG ship cold energy intelligent recycling technology uses various methods such as the direct expansion method, Rankine cycle method of the intermediate medium, and combined method to solve most of the power supply problems on the ship.


Introduction
The LNG ship cold energy intelligent recycling technology relies on the direct expansion method, the Rankine cycle method of intermediate media, the combined method, and other methods to achieve the recovery of residual LNG cold energy, including but not limited to the reuse of cold energy.The recovered cold energy is used for electrical appliances power generation, and cold storage refrigeration.The LNG intelligent recycling terminal controls the reused LNG cold energy and makes full use of it in other ways.

Outline of an evaluation system for the intelligent recycling of cold energy from LNG ships
2.1 Outline of an evaluation system for the intelligent recycling of cold energy from LNG ships LNG ship intelligent recycling of cold energy is mainly committed to studying how to recycle the waste energy wasted when LNG releases energy.The ship's propellers can turn the power generated by the energy into the power to push the ship forward, such as pulp, poles, sails, and propellers.In the shipping of LNG ships, the propulsion efficiency of modern traditional fuel ships is only 30%.However, if the intelligent recycling technology of LNG cold energy is applied in LNG ships, the propulsion efficiency of LNG ships will reach a new peak.The propulsion device used by LNG ships is mainly a dual-fuel propulsion device.Compared with the traditional steam turbine, the propulsion efficiency of the dualfuel propulsion device has been significantly improved.

Design framework for intelligent cold energy recovery and utilization evaluation system for LNG ships
The output pressure of LNG cold energy after gasification in China is about 8.0-9.5 Mpa, while the design pressure of LNG filling station storage tanks is only 1.6 MPa.Thus, during the shipping of LNG ships, the use of LNG cold energy will have a large part of residual energy.For this part of the residual energy, the LNG cold energy intelligent recycling technology is better utilized.The LNG cold energy is recovered either directly or indirectly and is converted into electrical energy for the use of various electrical equipment board the ship.The residual amount of LNG cold energy is then distributed to the various locations of the LNG vessel using different methods to ensure normal navigation and maximize energy utilization in intelligent system analysis.
The design architecture of the LNG ship cold energy intelligent recycling evaluation system is shown in Figure 1.The evaluation system of intelligent cold energy recovery and utilization of LNG ships mainly focuses on the recycling of LNG cold energy in the efficiency of ship propulsion and the intelligent recovery of LNG cold energy in various ways.In the form of big data comparison, sampling network big data, and field investigation, the comparison of propulsion efficiency of LNG ships and ordinary LNG ships can control the intelligent recovery of LNG cold energy through the intelligent recycling terminal of LNG ships and realize less manpower.

Technical route for the design of an intelligent cold energy recovery and utilization evaluation system for LNG vessels
LNG ship cold technology can use an intelligent recycling system to collect feedback information network transmission.According to the collected information through intelligent analysis and screening after the final technical route, the LNG ship cold can optimize the intelligent recycling evaluation system.The technical route of the LNG ship cold energy intelligent recycling evaluation system is shown in Figure 2. Information transfer requires the use of the system's initial information processing unit to automatically scan and collect the surplus energy recovered by the LNG ship's cold energy intelligent recovery technology during the release of energy.It stores it and sends a signal to the LNG ship's cold energy intelligent recovery and utilization terminal.After the information has been processed, the LNG ship cold energy intelligent recycling terminal uses energy identification scanning and scientific calculations to convert the collected energy into heat and energy utilization and generate a plan for the final use of LNG cold energy.This can be intelligently listed or processed in various ways to obtain the final LNG cold energy intelligent recycling technology route.

Components of an intelligent LNG ship cold energy recovery and utilization evaluation system
The LNG ship cold energy intelligent recycling evaluation system is conducive to energy saving and expenditure saving.The LNG ship cold energy intelligent recycling evaluation system includes four analysis function modules: intelligent recycling source analysis, cold energy recovery rate evaluation, cold energy utilization terminal analysis, and cold energy utilization rate evaluation.Applying the LNG ship cold energy intelligent recycling technology, the recovery and utilization technology consist of LNG cold energy recovery device, LNG heat exchanger inductor automatic control valve, filtration device, flow valve, power generation, and recovery device, circulation and cooling device and connection piping.
The LNG ship cold energy intelligent recycling terminal analyzes the source of intelligent recycling to obtain the location and quality of LNG cold energy release.Then through the cold energy recovery rate evaluation system, the intelligent LNG cold energy recovery rate change is projected.The utilization rate of LNG cold energy is projected after the cold energy is collected and utilized in cold storage, air conditioning, and other fields.The automatic control valve of the LNG heat transfer device can be intelligently uploaded to the main LNG ship cold energy intelligent recycling system according to the change in LNG gas temperature.After generating the changed information backup, it intelligently controls the switch of LNG cold energy in and out of the storage device through the originally set temperature limit data.Filter devices can screen for large stain particles and harmful substances such as small bacteria.The flow valve can be set according to the actual application and adjust the flow rate of LNG cold energy so as to avoid excessive energy waste or the phenomenon of energy supply.The circulating cooling device effectively retains the heat consumption generated by LNG in the intelligent cold energy recovery and utilization of LNG ship technology for recycling.

Intelligent recycling and evaluation system for LNG ships' cold energy energized intermediate component
The most important indirect use of LNG cold energy is through "cold energy generation".Cold energy generation is the recovery of LNG cold energy in the form of electrical energy, mainly by using the lowtemperature cold of LNG to liquefy the process mass, which is then heated and vaporized, and expanded in a turbine to produce electricity.
The LNG ship cold energy intelligent recycling evaluation system consists of four functional modules: intelligent recycling source analysis, cold energy recovery rate evaluation, cold energy utilization terminal analysis, and cold energy utilization evaluation.The components consist of an LNG cold energy recovery unit, an automatic control valve for the LNG heat exchanger inductor, a filtration unit, a flow valve, a power generation recovery unit, a circulation cooling unit, and connection piping.The additional cold energy released by LNG is intelligently collected by the LNG cold energy recovery device.It is then evaluated and analyzed by the cold energy recovery rate evaluation of the LNG ship's cold energy intelligent recovery and utilization technology for the subsequent utilization.The LNG cold energy is utilized in indirect ways, such as cold energy generation.Once the LNG cold energy has been utilized, the cold energy utilisation measurement module will generate a measurement to produce the results.

Simulation analysis of the applicability of intelligent cold energy recovery and utilization evaluation system for LNG ships
In LNG ships, electrical equipment requiring power supply is also a major fuel requirement, but the problem of power supply in ordinary LNG ships has not been effectively solved.The recovered cold energy can be used to generate electricity for air conditioning, electricity supply, low-temperature medical treatment, food preservation, and more.The applicability analysis of the evaluation system for the intelligent recycling of cold energy from LNG ships is shown in Table 1 At a technical level, depending on the needs of different LNG vessels, there will be correspondingly different technologies to recover the LNG cold energy from that vessel.For ships that have been shipping at sea for a long time and require a large amount of LNG cold energy as fuel, the temperature difference between LNG and the refrigerant carrier, the heat exchange between the refrigerant carrier and seawater, and the transfer of cold energy can be used to desalinate seawater in order to obtain freshwater products and ice products.

Conclusion
With the large number of LNG ships in use and the increasing amount of LNG resources worldwide, the rational use of LNG cold energy and the effective recovery of the residual energy released by LNG cold energy has become a sub-project of the Guangxi Innovation-driven Major Project "R&D and demonstration application of new inland river high technology green cargo ships".The technology is used to utilize the wasted heat and the cold energy released during the LNG gasification process to generate electricity with a temperature difference, thus saving resources and reducing costs.During LNG cold energy recycling, whether it is air separation or residual energy generation, or rare gas production, a variety of methods can be combined and optimized to achieve a full and rational use of the residual energy left by LNG cold energy utilization.This achieves the goal of developing new energy sources and saving resources, as well as meeting the future trend of national resource development.

Figure 1 .
Figure 1.Design architecture of the evaluation system for intelligent recycling of cold energy from LNG ships

Table 1 .
. Applicability analysis of intelligent cold energy recovery and utilization evaluation system