Electric-discharge cleaning of stationary sea platforms of biological growth

Abstract

The increasing of production of crude carbohydrate material on the Black Sea shelf is one of the priority directions of the oil and gas complex of Ukraine. In this case, it is of great importance to support safe operation of stationary sea platforms whereby oil and gas are produced on the shelf. Intensive biological growth on the platform bottoms substantially affects their durability and safe operation and requires periodic (three or four times a year) cleaning of the metal construction. The present traditional techniques of cleaning are not suited to all the requirements for the quality, time frame, and cost of the work. The most-used mechanical removal is not adequately profitable and is marked by a high cost and labor output ratio. For example, an imported apparatus such as Brashkart or Cavi-jet at a cost of up to 100‐150 thousands dollars requires significant costs for execution of diving. Thus, the development and adoption of new safe and enabling technologies of cleaning of the metal constructions of stationary sea platforms of biological growth are problems of considerable interest. The electric-discharge method as an efficient and safe cleaning technique is suggested as an alternative to mechanical removal. Studies found that this method allows one to clean metal surfaces with the required capacity with low expenditures of energy [1]. However, for execution of the work in a medium having increased conductivity (sea water), it is necessary either to deliver a great amount of fresh water to the discharge area or to stabilize the discharge with exploding wire, dielectric string, or a magnetic field. This causes the complication of the design of the technological and electric devices and significantly increases the mass and overall dimensions of the apparatus, which is unacceptable under the conditions of work on stationary sea platforms. The method of cleaning of metal constructions of stationary sea platforms of biological growth using pulse corona discharge allows one to perform the process in a medium having increased conductivity, which greatly simplify the design of the technological and electric devices and reduces their mass and overall dimensions. This technique has prospects for widespread adoption both on the domestic market and on the foreign one. The introduction of the technological process of electric-discharge cleaning of stationary sea platforms of biological growth based on pulse corona discharge substantially reduces the cost for the support of the safe operation of oil and gas complex objects and the periods of the execution of repair and preventative work. The use of corona discharge is based on the realization of intense generated hydrodynamic disturbances. Such a feature is intrinsic to pulse corona discharge in strong electrolytes in water. These latter have corona as continuous plasma formations, whose shape can be modified. Consequently, pressure fields of specified configuration in liquid can be formed [2].