Gas Material, Processing and Power Technologies

*Advanced-Auto Thermal Gasification

Introduction

Environmentally-friendly natural gas is receiving international attention as alternative energy to oil. However, in its gas form, natural gas is difficult to handle and transport. For reasons of production cost and profitability, to date natural gas has been explored mostly from large-scale gas fields.
Yet, natural gas from small- and medium-sized gas fields and associated gas from oil fields make up half of the total volume of proven reserves remain unutilized due to the difficulty of creating and developing such business. Moreover, the associated gas released during the oil production process is not utilized. The need therefore exists for GTL (gas-to-liquids) conversion technology that promotes the utilization of such natural gas.
Firstly, natural gas is converted into synthetic gas which consists primarily of hydrogen and carbon monoxide. GTL diesel oil, GTL kerosene, DME and so on are produced from synthetic gas. The technology offers a number of significant benefits. GTL Products can be transported and stored at normal temperatures. Furthermore, GTL products are cleaner than petroleum-based fuels, since the exhaust gas contains considerably lower levels of NOx and no SOx. The construction cost of synthetic gas production system accounts for approximately half the total GTL plant cost. Therefore there has been a considerable incentive to develop more compact process with high energy efficiency.
Osaka Gas and JGC Corporation have been jointly developing a new synthetic gas production process (A-ATG process) with the financial support of JOGMEC (Japan Oil, Gas and Metals National Corporation) between 2003 and 2007. The project aim is to develop an innovative, highly-efficient and low-cost synthesis gas production process.

 

Process flow

Features

The Advanced Auto-thermal Gasification (A-ATG) process is a synthesis gas production process that combines ultra-deep desulphurization developed by Osaka Gas with Catalytic Partial Oxidation.
The following points summarize the most significant features of A-ATG process compared with conventional process that combines steam reforming reaction and Auto Thermal Reforming (ATR) reaction with a burner.
*The conventional process has a pre-reformer for steam reforming, a fired heater to provide heat necessary for steam reforming and an ATR reformer with a burner. On the other hand, A-ATG process is a very simple process that produces synthetic gas in only one fixed bed reactor.
*Compared to the conventional process, significantly higher SV (space velocity: 1/hr) of A-ATG reaction can be achieved permitting a smaller size reactor. This high speed reaction is supported by the world-renowned high level desulfurization catalyst developed by Osaka Gas. This technology enables desulferizing at ppb level and consequently extended periods of operation become possible since the downstream catalyst is not deactivated.
*Our reforming catalyst can initiate oxidation stably at an inlet temperature of below 300 degrees Celsius and lower peak temperature inside the catalyst bed because of high steam reforming activity.
*The ATR reactor with a burner system has a problem of soot. On the other hand, this problem hardly occurs in A-ATG process because the oxidation reaction and steam reforming reaction can be operated simultaneously in the catalyst bed.
*A-ATG process can reduce carbon dioxide emissions in synthetic gas production process because the fired heater for steam reforming in conventional process is eliminated.
*A-ATG process can reduce construction cost substantially because of process simplification and compactification.
*A-ATG process, synthetic gas production process is applicable not only to GTL plant but also to a chemical plant, an ammonia plant, a methanol plant, a DME plant and so on.

Past achievements and Future effort

The various verification operations using oxygen manufactured by a cryogenic air separation unit were implemented with the pilot plant. The production capacity of the pilot plant is 2,000Nm3/h in synthetic gas and sufficient to produce 65 barrels of GTL products per day. Those operations proved that the performance of the A-ATG process is safe, stable and suitable for synthetic gas production process of GTL plant. We conducted a feasibility study for a commercial plant of A-ATG process based on the engineering data accumulated through the verification operations. And we confirmed that A-ATG process is superior to the conventional process in terms of construction cost and carbon dioxide emissions.
Now we are pushing ahead with this development under the major theme of followings.
*Commercialization of A-ATG process in the field of chemical industry.
*Implementation of the various verification operations using low concentration oxygen manufactured by a pressure swing adsorption unit and/or air. The purpose is further cost reduction and extension of applicable fields to offshore GTL plants using natural gas from small- and medium-sized gas fields and associated gas from oil fields.
*Implementation of research and development of further scale-up method.