Advantages Of Building LNG Liquefaction/Storage Plants On Floating Barges

ABSTRACT A barge-mounted natural gas liquefaction and storage facility, the so-called Marine LNG System (MLS) developed by Moss Rosenberg Verft, has been proposed for installation in the Persian Gulf to serve a project intended to send LNG to the east coast of the U. S. The MLS was proposed for this service because of advantages of lower project capital cost, shorter time from contract to startup and the availability of project financing. The MLS is built in a shipyard in a developed country and is towed for startup and operation in the gas-producing country. All, of the skills, equipment and cost controls inherent in modern well managed shipyard production are applied to the MLS building. This paper presents an engineering overview of the MLS project, including descriptions of the gas liquefaction process plant, the LNG storage, and the barge mooring/gas feed line, as well as control and safety features. The construction sequence and ship yard building schedules are presented. Representative costs for an LNG project utilizing the MLS are presented. Using the building schedules and costs, an analysis of liquefaction cost for LNG delivered at the MLS ship loading rail is presented. INTRODUCTION Gas hydrocarbon deposits are frequently found in parts of the world where development and production are especially difficult, time consuming, and costly due to the remote, sometimes hostile location, the lack of trained construction labor, and the absence of a developed infrastructure. Not uncommonly, these deposits are located offshore, miles from the coast. In order to facilitate the development and production of such gas resources by keeping control of building schedules and costs, developers are becoming increasingly interested in plant building procedures not common in the industry today as alternatives to the conventional build-on-site procedures. One such alternative is the Marine LNG System (MLS), which Moss Rosenberg Verft has developed over the last four years. The MLS is a floating integrated plant for gas liquefaction, LNG storage, and LNG ship loading, built in a shipyard and towed to the gas production site complete and ready for startup and run in. LNG projects have to date been characterized by two basic problems: inadequately controlled capital costs and late startup. It is not hard to appreciate the reasons for these problems when we consider the difficulty in building a sophisticated process plant on the hot desert shores of some remote bay. Virtually everything involved in such a project, from workmen to materials and equipment must be shipped in and built on site according to a construction schedule which may span four to five years. As a shipbuilder concentrating on building specialized tankers for the transport of LPG and LNG, Moss Rosenberg Verft has for years closely watched the development and construction of base load plants for LNG production.