Beyond the optimisation of the commercial prototype technologies outlined above, the next prospects are at an early stage and the market prospects are not yet clearly determined.
Coal (syngas)-to-ethanol
There is a potentially significant industrial demand for ethanol, for which several production methods are available, including the conversion of coal-based syngas (Figure 13).
Figure 13 Coal-to-ethanol conversion process schemes (Asiachem, 2012)
The options include the conversion of acetic acid either by direct hydrogenation or via esterification then hydrogenation, using coal-based syngas as the raw material source. The SOPO Group has carried out pilot-scale trials of a syngas-to-ethanol technique that was developed jointly with the CAS Dalian Institute of Chemical Physics and the Wuhan Engineering Company. This uses a silica-base catalyst to convert coal-based syngas and, through the process flow of hydrogenation and separation, to a product conforming to both the specifications of premium industrial ethanol and fuel grade ethanol (Asiachem, 2013). From a market perspective, the volume for industrial ethanol is limited and so this industry will only become significant if ethanol can be used as a blend with petrol in the transportation sector. This is dependent on the establishment of positive Chinese policy and regulations and it remains to be seen whether a coal-based production process will win any market share available compared to a bio-process. Even then, the end product is likely to face competition from the use of batteries and natural gas as alternative approaches.
Coal-based polygeneration
On the assumption that the technical improvements outlined above can be achieved, there is an expectation that China will establish the use of a portfolio of coal gasification technologies, to demonstrate integrated gas, electricity, and chemical polygeneration, with ‘near-zero’ emissions. This includes the research, development, and demonstration of modern coal conversion technologies, where coal is both a fuel and a feedstock, and can be used in conjunction with other energy sources. The first stage might comprise a gasification-based system, primarily for power and heat production. This can be designed so that when market demands for electricity and heat are met, various clean energies and industrial raw materials, including natural gas, liquid fuels with ultra-low emissions, aviation and specialty fuels, and chemicals can be produced via the gasification-based coal conversion system (Figure 14)
Figure 14 Schematic for a coal-based polygeneration system (Power, 2014)
The second phase could incorporate coal with both unconventional energy and renewable energy systems. An indicative example is shown in Figure 15. Such an approach seems attractive in principle and would certainly meet the State Government’s wish to encourage innovation in industrial energy production and use. However, it is as yet at the concept stage and will need careful consideration of the challenges as well as perceived advantages to determine that it is a reasonable financial investment within the coal-to-chemicals sector.
Figure 15 Framework for a multi-energy system based around coal polygeneration (Ni and others, 2014)
- Bumi Resouces
- Adaro Energy
- Indo Tambangraya Megah
- Berau Coal
- Bukit Asam
- Baramulti Sukses Sarana
- Harum Energy
- Mitrabara Adiperdana
- Samindo Resources
- United Tractors
Source: IEA Clean Coal Centre
