Japan Oil, Gas and Metals National Corporation (JOGMEC), which is a former Japan National Oil Corporation (JNOC), has been developing natural gas to liquids (GTL) conversion technology since the year of 1998 in collaboration with five private Japanese companies, namely; JAPEX Co. Ltd., Chiyoda Corp., COSMO Oil Co. Ltd., Nippon Steel Corp., and INPEX Corp. Our new GTL process is particularly effective when it is applied to natural gas feed stock containing 20–40mol% of CO2. It does not require the three expensive items;an oxygen supply plant,a unit for CO2 separation from natural gas, anda H2 separation unit to optimize gas composition.
The reduction of these facilities, which are indispensable to the conventional GTL process, would results in less CAPEX and OPEX.
For our new GTL process, the most preferable CO2 content in feed natural gas is around 30mol%. Therefore, in case that the CO2 content is less than 30mol%, some amount of CO2 can be supplied from other CO2 sources, such as flare gas, associated gas, remaining CO2 of EOR and exhausted gas from oil refinery and LNG plant.
This paper aims to present applications of our new GTL process to enable an economic exploitation of gas reserves in South East Asia and Australia, by taking into account the operation results of the Yufutsu GTL pilot plant of 7BPSD located at Tomakomai city in Hokkaido of Japan, and the study results of process simulation and the economics. We present an attractive combination scheme for our new GTL process with LNG plant by utilizing CO2 exhausted from LNG plant. It reduces initial project's investment compared with a stand-alone GTL plant located in South East Asia and Australia, where infrastructure of an LNG plant can be for common use with our GTL plant.
Introduction
Our new GTL process is an attractive way to moneitze stranded gas resources. It can handle natural gases containing CO2 as feed stock for GTL and furthermore it is effective for gas reserves far located from an existing market and/or left undeveloped due to high cost of transportation like pipeline system and/or conversion to LNG. Prevailing GTL products have remarkable characteristics such as being sulfur free and aroma free. These are important for the existing oil market, particularly in circumstances reinforcing environmental restrictions on emissions in the advanced nations. To enable this, it is first necessary for the GTL process to make a further improvement on the following points;development of optimal catalysts applicable to the Syngas reformer and the FT reactor with a high performance of conversion from gas to liquids, andoptimization of energy efficiency.
It is also necessary for gas producing countries to provide natural gas feedstock at a low price and/or prepare supporting mechanism such as a GTL tax preference, GTL subsidy, and so on. Gas producing countries will thus boost the competitiveness of GTL products, so that it will be possible to increase GTL business as well as the natural gas business.
New GTL Process
Steam/CO2 reforming in the Syngas reformer is one of particularities of our new GTL process as appears on Figure1, which illustrates main distinction between our GTL process and conventional GTL processes. The Syngas Reformer efficiently uses CO2 included in the natural gas feedstock and it enables to produce Syngas, which consists of H2 and CO with the composition molar ratio of H2/CO=2/1. Thus, our GTL process is capable to utilize CO2 contained in the natural gas and does not require any O2 supply. Namely, the characteristics of our GTL process in contrast to those of the existing ones using ATR or POx are (1) no use of the O2 generator, (2) no use of the CO2 removal unit, and (3) no use of the H2 conditioning unit for Syngas.
The Syngas will be introduced to the subsequent FT Reactor to convert it to GTL production oil.
