ABSTRACT

This paper presents concepts toward the development of a system for the marine transport of natural gas in hydrate form, potentially at competitive cost. A natural gas hydrate system can reduce the volume of natural gas by betw.een 160 to 175 times, while maintaining a high degree of safety. Gas hydrates are relatively safe as the ice matrix (with its high latent energy) must melt before the flammable gas is released. The conceptual hydrate system discussed in this paper would essentially consist of processing/regasification facilities either onshore, or offshore, with prestressed. high-strength lightweight concrete surface vessels used for the transportation phase.

INTRODUCTION

Gas hydrates are technically an alternate form of ice that entrains the gas within cavities in the crystal lattice. Entrainment of natural gas within an ice matrix results in an intrinsically safe transport technology as the. ice matrix, with its high latent energy, must be melted before large volumes of gas can be released. ·Thus unlike liquefied natural gas, LNG, systems, or compressed natural gas systems, the explosive release of natur.al gas during an accident is inherently inhibited in a natural gas hydrate system. For practical considerations, gas hydrates can only decompose when sufficient thermal energy is provided to melt the hydrate structure. Thus even if the hydrate carrier structure were to accidentally depressurize, the rate of release of gas would be limited by the thermal gradients, and heat flow, into the vessel. As hydrates have a latent heat of melting slightly higher than that of ice it takes a considerable amount of energy to decompose the hydrates and release the entrained gas. If a hydrate mass is ignited under atmospheric conditions, it will burn slowly and will not explode.

This content is only available via PDF.
You can access this article if you purchase or spend a download.