CNG Transportation Utilizing Composite Pressure Vessels

Abstract

Abstract The Trans Ocean Gas CNG transportation method, which utilizes composite pressure vessels and modular cassettes to store natural gas, overcomes the safety, corrosion, excessive weight, and cost deficiencies of all other proposed CNG trans-portation methods. The method also has the ability to extract NGL's while on route, removing the requirement of stripping gas on an offshore structure. Introduction The following paper describes an innovative method of CNG transportation. The method utilizes composite pressure vessels which are derived from the national defense / aero-space, and natural gas vehicle industries. The method over-comes all of the deficiencies anticipated from other proposed methods of CNG transportation that propose to use steel based gas containment systems. Existing container ships may be optimized through the use of the cassette gas containment system. The cassette system also isolates composite gas pressure vessels from ship-induced forces. Being modular, installation and removal of cassettes would be relatively easy. The cassette storage system will provide significant economic advantage over potential com-petitors commencing with a pilot project. This paper will conclude that The Trans Ocean Gas CNG Transportation Method, offers a high level of safety, reliabil-ity, and economic feasibility. Background. The first Compressed Natural Gas (CNG) pilot project using steel pressure vessels mounted on the deck of a ship was conducted off the coast of New Jersey in 1966. It was concluded as not being feasible since the weight of steel pressure vessels required would be too heavy for the host ship to carry. CNG development then stagnated for thirty years. Over the past decade, the increased lucrative potential of CNG has renewed interest and spawned several innovative concepts. All but one proposed method use steel containment systems, which still have issues of safety, corrosion, excessive weight, and cost. All of the proposed methods using steel con-tainment systems are requesting factors of safety less than that of the ASME code. In 1999, author, Mr. Steven Campbell developed a method of CNG transportation that overcomes all of these deficien-cies. This method, licensed exclusively to Trans Ocean Gas Inc. of St. John's Newfoundland, proposes to use composite pressure vessels (CPVs) to safely and cost effectively trans-port up to 1.7 Bcf of natural gas by ship. CPVs have been successfully used in the national defense / aerospace industry since the early 1970's. About 10 years ago, the natural gas vehicle industry started using CPVs for busses, fleet vehicles, and automobiles. CPVs are also used as accumulator bottles for riser tensioning systems on oil and gas TLPs. The CPVs proposed for a ship-based CNG transporta-tion method are similar, but larger than those currently used for natural gas driven buses. Since CPVs have been success-fully used to store natural gas for fuel on public busses, they are well justified for use in a ship-based CNG transportation system.