The foreign team developed a 15kW underwater laser cutting system with a rated depth of 500 meters

The special underwater environment is bound to make underwater laser cutting quite different from the common laser cutting in the air in terms of cutting process and cutting equipment, and affect the final cutting effect. In the future, laser may be expected to provide a low-carbon, fast and clean underwater cutting method for the dismantling and scrapping market. The relevant scenarios include the dismantling and maintenance of equipment and facilities such as oil and gas, nuclear power and offshore wind power, as well as dangerous operations such as underwater search and rescue.

The optimization of laser power, gas pressure, cutting speed and other process parameters to reduce the absorption and scattering of light by water molecules has become the key driving force of underwater laser cutting technology. At present, many studies at home and abroad have made unremitting efforts in this area. For example, since 2019, engineering service companies Claxton Engineering, the University of Aberdeen and the National Decommissioning Centre (NDC) have been cooperating to develop underwater laser cutting systems with power up to 15kW.

(Image source: Claxton Engineering)

In the current test, when cutting 25mm thick stainless steel, the cutting speed of this underwater laser cutting system is as high as 300mm/min, which is the fastest speed that the test device can move at present. According to the above partners, the cutting speed will become faster after the cutting process is further optimized.

In the first stage of cooperation, 250 underwater cutting experiments have been conducted, and the system can cut structural steel with a thickness of 120mm at a depth of 70m. In addition, the rated depth of the cutting head that can be operated underwater can reach 500m. At this stage, the technical maturity of this 15kW underwater laser cutting system has been verified to reach level 6 and is suitable for further development.

The second phase of cooperation is planned to be carried out from 2023 to 2024, including further development of underwater laser cutting system and operation test in actual marine environment. In order to better manipulate the existing cutting head in specific applications, the above partners will cooperate to develop a special cutting tool.

The performance of the second stage will be verified in the actual offshore cutting environment, and will be compared with the typical mechanical or abrasive cutting solution. The purpose is to prove that the system is a mature cutting technology and suitable for a series of related applications. The technical maturity of the system at this stage is 7, which is suitable for further commercialization.

(Image source: Claxton Engineering)

At present, there are several mainstream seabed cutting methods that can be effectively used for dismantling and scrapping of offshore facilities, such as abrasive water jet, diamond wire cutting and plasma arc cutting. Among them, the application potential of laser underwater cutting is very huge - for more and more large energy equipment and facilities (such as nuclear power plants) that are going to die, this will become a safe way to dismantle. It is reported that BP, Shell, ConocoPhillips and other companies have tried to use laser underwater cutting to remove and decompose relevant retired equipment. A report entitled Offshore Oil&Gas Decommissioning 2023-2033 recently released by Visiongain, a market research company, shows that the global offshore oil and gas decommissioning market in 2022 is worth 10.275 billion US dollars, and is expected to grow at a compound annual growth rate of 6.5% during the forecast period of 2023-2033.

In the future, laser cutting can be widely used to process radioactive components stored underwater, so that they can be repackaged and assembled for future processing or storage. In addition to being able to cut the structure from the internal and external positions, underwater laser cutting is also safer, cheaper and faster than traditional cutting methods (such as water jet or diamond wire cutting). At the same time, it takes less space and uses less materials. It is also conducive to significantly reducing the pollution of hazardous waste generated during the disassembly of equipment due for service and improving the efficiency of the entire operation execution process. However, sawing and water jet cutting will produce secondary waste, and then water needs to be filtered out. In addition, with the help of high-power underwater laser cutting, it is expected to create cutting equipment that can operate efficiently in extreme water depths.

Source: OFweek