Australian Liquid Fuels Tech Assessment

https://industry.gov.au/Office-of-t...alian-Liquid-Fuels-Technology-Assessment.aspx

Australian Liquid Fuels Technology Assessment



This pathway is based on technology developed by New CO₂ Fuels (NCF) and involves producing fuel via a synthesis gas to methanol route from CO₂ and water feed using high temperature heat from a solar collector. The synthesis gas is further processed into methanol and subsequent liquid fuel products DiMethyl Ether (DME) and Gasoline (ref technology 16(a) DME and 16(b) MTG discussed below).

Extensive stakeholder input has been received from NCF within the limits of confidentiality for their technology (New CO₂ Fuels 2014a; New CO₂ Fuels 2014b).

Other developing solar fuels technologies were not selected due to a lack of information and engaged stakeholders.

Australian context

NCF technology requires access to a relatively pure stream of CO₂, such as from an acid gas separation system in a natural gas processing plant, ammonia synthesis process, or a coal or biomass gasification plant. Water is also required, although this is likely to be entrained in the acid gas stream in sufficient quantities not to require an additional source.

The NCF is a high temperature thermally and electrically driven dissociation reactor which converts CO₂ and H₂O into synthesis gas and a separate stream of oxygen. The NCF reactor can be driven from a solar thermal plant and/or excess heat from industrial processors and/or other high temperature heat sources. For this study, the solar thermal configuration has been assessed. Australia has some of the best solar resources in the world to locate a solar thermal plant.

The DME and MTG via methanol routes to a final fuel have been selected rather than a Fisher‑Tropsch (F-T) pathway. Methanol is a transportable intermediate product that could realise economies of scale if transported to a centralised DME or MTG plant.

The location selection for a 100 per cent solar plant is constrained in the Australian context. The localised oxygen production is of the same order as the largest currently installed Air Separation plants in Australia. However, the natural gas or ammonia plants that are the assumed CO₂ suppliers are not large oxygen consumers. Australia does not currently have any significant gasification-based synthesis gas production that would supply CO₂ and consume O₂.

Barriers/Opportunities

The NCF process uses CO₂ as a feedstock and could be an effective CO₂ sink.

Oxygen production is normally located directly adjacent to its consumption to avoid transport costs, which, by cylinder or cryogenic truck, are very high. This limits the application and location of NCF plants. In Australia, locations of large oxygen consumers include steel smelters (Port Kembla 150,000 t/y oxygen), titanium dioxide (Kwinana 110,000 t/y) and nickel smelting (Kalgoorlie, 150,000 t/y).

The oxygen production from NCF is greater than the fuel methanol production in quantity and, potentially, value. If a market price of $250 per tonne for oxygen is applied to this “by-product”, then the LCOF of methanol is a large negative cost, due to credit from the oxygen. If the oxygen is assumed to be vented then the LCOF is a large positive cost due to the high unit capital cost for the project. This technology may be just as applicable for its oxygen output as for its synthesis gas output in certain markets.

Process technology

A simplified flow scheme of the production process of solar dissociation methanol is shown in Figure B8 in Appendix B. The technology parameters used in estimating the LCOF of solar dissociation methanol are presented in Table 14. Solar energy is collected in concentrating parabolic dishes that track the sun to maximise output. Heat from the solar energy and electricity are used to dissociate CO₂ and H₂O at 850°C to form a synthesis gas of CO and H₂ plus a separate O₂ stream. Waste heat is recovered to provide the electricity required for the reaction through a steam Rankine cycle. A methanol plant is included on site and processes the synthesis gas into methanol. Methanol is then transported to a larger scale facility where it is further processed into the transport fuel products DME or Gasoline.
This study assumes that the process takes place in a region with high solar radiation, greater than 1,800 kWh/m²/yr, with sources of high purity CO₂ and water. For the purpose of this study, the most likely applications are natural gas processing facilities and ammonia plants where a stream of high purity CO₂ mixed with H₂O is currently vented.

Oxygen consumption is assumed as 10,000 tonnes per year valued at the market price of $250 per tonne. This assumes a 50 per cent share of one of the capital city markets, estimated at 20,000 tonnes per year of O₂. Solar Fuels dissociation of CO₂ is a new technology proven at the laboratory scale with a small scale prototype recently declared to have dissociated CO₂ with an external heat source.