Gasification

One of the main methods of hydrocarbon conversion is called gasification. Gasification basically involves transforming carbon-rich fuels into synthesis gas (sometimes called syngas) through gas separation, partial oxidation or steam reforming. Subsequently, CO is converted to CO₂ through the shift conversion reaction producing a stream containing mainly high purity H₂ and CO₂.

Efficiencies achieved

The gasification process described here is called "pre-combustion capture", and it has demonstrated significant efficiencies over other methods:

• the partial pressure of CO₂ is very high compared to post-combustion systems, making it much easier to separate and capture;
• the recovery conditions significantly reduce the CO₂ compression costs and power requirements, resulting in a noticeably smaller loss of net efficiency;
• the main products are hydrogen or electricity for consumer applications, giving gasification a strategic flexibility for future energy requirements.

Looking ahead

As we continue to research into enhancing pre-combustion technologies, we seek to improve gasification as a viable choice for carbon conversion. We face some barriers to its success. These are the types of questions we're looking to answer:

• How can we reduce the cost of pre-combustion systems?
• Can gasification technology (as it exists) be used effectively on low-rank Canadian coals such as the sub-bituminous and lignite coals in western Canada?
• How should we address hot gas clean-up and issues related to pure hydrogen-fired turbines?

We intend to tackle these and other issues. We know that second generation concepts are needed: ones that incorporate improved processes for shift reactions and for H₂/CO₂ separation. These concepts will need to include more energy efficient CO₂ and multi-pollutant capture processes that apply to low rank coals.