Hydrogen Balancing in a Gas-to-Liquids (GTL) Plant

Published April 2015

There is abundance of natural gas available in many areas of the world, and natural gas is predicted to be available longer than oil reserves by a significant margin. However, natural gas reserves are found in remote areas where it is uneconomical to develop them, due to the lack of local demand and the high cost of transporting the gas to distant markets. This high cost is caused in part by the extremely low temperatures needed to liquefy natural gas to LNG for transport. One alternative is to convert the natural gas into liquid hydrocarbon products locally, which can be transported more cost-effectively, closer to ambient conditions. There are many processes for converting light hydrocarbon gases such as natural gas, to heavier hydrocarbon liquids. One such process is commonly known as gas-to-liquids (GTL) production. This involves the conversion of natural gas to synthesis gas (syngas) comprising hydrogen (H₂) and carbon monoxide (CO), followed by feeding the syngas to a Fischer-Tropsch (F-T) process for conversion to primarily C₅s+ hydrocarbons. GTL production includes various processes and steps that consume hydrogen. It is desirable to optimize GTL production by balancing hydrogen production in the syngas production with hydrogen consumption in the F-T process. Managing hydrogen generated from the natural gas (or from other sources) provides increased process flexibility and reliability in Fischer-Tropsch process or overall GTL plant.

This PEP review focuses on calculating the hydrogen requirement in various steps of Fischer-Tropsch process, and then balancing it with hydrogen production.