BHP Petroleum and Diamond Research & Development Australia Pty Ltd (a wholly owned subsidiary of Mitsubishi Corporation) have developed a detailed design basis for Methanol Floating Production Storage and Offloading (MFPSO) facilities using a new compact natural gas reforming process and existing low pressure methanol synthesis technology developed by ICI.
This paper will describe the three main development steps - choice of process, proving of the new compact reforming technology and detailed MFPSO technical feasibility studies, completed to fully assess the suitability of the concept for offshore application. The preferred design is based on a single train reforming system and is applicable to a range of plant capacities up to approximately 4500 t/d. This is nearly twice the capacity of many of the large single train land based methanol plants which employ conventional reforming technology. Detailed capital and operating cost estimates have also been prepared. As a result it is now possible to fully evaluate whether specific hydrocarbon resources are suitable candidates for monetisation using an MFPSO.
It has been concluded that the production of methanol from natural gas on an FPSO is safe and practicable. The technology developed offers a real alternative to gas reinjection on developments where flaring is prohibited, or as a method of commercialising stranded gas resources.
The perceived need to be able to economically convert quantities of gas into marketable liquids offshore has been increasing over the past few years. This has generally resulted from anticipated future flaring restrictions on the associated gas production from new oil developments (environmental pressures to reduce greenhouse gas emissions and conserve resources are increasing). There is also an increasing desire to monetise significant volumes of stranded gas and add value to marginal oil discoveries.
Apart from LNG production, the other option for gas conversion in remote or deep water offshore locations, where pipeline distribution or reinjection of the gas is impracticable, is the conversion of the low value gas to synthesis gas and subsequently to a derivative liquid of choice. Methanol and Fischer Tropsch products are the main synthesis gas derived liquids that currently have well proven synthesis processes and established markets, although at vastly different market sizes.
A new driver for developing offshore gas to liquids technology is an anticipated future need for more environmentally friendly fuels.
