http://www.anl.gov/PCS/acsfuel/preprint%20archive/Files/47_1_Orlando_03-02_0129.pdf
We have previously cited, as in "Methane conversion to higher hydrocarbons in the presence of carbon dioxide using dielectric-barrier discharge (DBD) plasmas; Plasma Chemistry & Plasma Processing, 2001",
and will further cite, the work of Swiss scientist Baldur Eliasson and his Chinese co-workers in the field of Carbon conversion technologies.
Herein, Eliasson, et. al., reveal, in confirmation of previous reports we've submitted, that Methane, as can be synthesized from Carbon Dioxide, via Sabatier-type reactions, or from Coal, via hydrogasification, can serve to improve the production and efficiency of some indirect Coal-to-liquid conversion processes.
Our understanding, from other references, is that the word "plasma", as it is used herein and as applied in these technologies, refers to a, relatively, "low-temperature" gas chemistry phenomenon, and does not imply the high-temperature, high-energy processing environments which might normally be associated with plasma phenomena.
The excerpts, with comments inserted and appended:
"PRODUCT ANALYSIS OF A NOVEL SYN-CRUDE SYNTHESIS DIRECTLY FROM A COMBINED CONVERSION OF COAL AND METHANE
Yu Wang, Yang Li, Jijun Zou, Baldur Eliasson, and Chang-jun Liu
1. State Key Laboratory of C1 Chemistry and Chemical Technology,School of Chemical Engineering and Technology, Tianjin University,Tianjin, China
2. Energy & Global Change, ABB Corporate Research Ltd., Baden, Switzerland
Introduction
Mankind has been used to an ever-growing supply of cheap and abundant fossil energy including coal, oil and natural gas for more than 150 years. Especially, cheap oil has played an important role in the booming economic all over the world. The consumption of fossil energy is challenging us due to some global problems. The first problem is the degradation of the environment. The second one is the lack of availability and security of oil. To solve these problems, one has to improve the efficiency of energy consumption
and develop alternative fuels simultaneously. Since the safe nuclear energy technology is still in the development, alternative fuels and renewable energy become very important in the present world.
Methane is a principal component of natural gas, coalbed methane, associated gas of oil field and some by-product gases of chemical plants. There is a plentiful resource of methane. The utilization of methane is very important to keep the safe and reliable energy supply in the coming new century. On the other hand, there is a huge reserve of coal all over the world. Especially, the major fossil fuel consumed in China is coal. An intensive investigation has been conducted to develop technologies for the clean use of coal in China. Due to its low H/C, it is still difficult to chemically utilize coal. Since methane owns a higher heat value, with its high H/C ratio, it is very promising to combine the utilization of methane and coal. Especially, it will be very
promising if we can produce liquid fuels directly from conversions of coal and methane.
The industrialized synthetic fuel production from coal or methane claims a multi-step process. First, the syngas (CO+H2) is produced and the liquid fuel is then produced from syngas.
However, there exist some difficulties in such fuel production. First, the process of the production of syngas is an endothermic reaction and requires a high temperature for a favoured equilibrium. This is a very energy-intensive process. Second, further reactions of syngas, like F-T (Fischer-Tropsch) synthesis, need high-pressure operation for a reasonable conversion. Therefore, the produced syngas has to be compressed. This also consumes extra energy. For the comercialised set-up of fuel synthesis from syngas, more than 60% of the cost goes to the production and compression of syngas. The high-energy consumption and high investment in set-up limit the application of multi-step conversion. Especially, such multi-step utilization is not suitable for on site coal or methane conversion at remote sites by far. It is very necessary to improve such multi-step utilization of coal or methane simultaneously exploits new techniques. Among all the new technologies under developing, the non-thermal plasma conversion is very promising. Since non-thermal plasma is a mixture of electrons, highly excited atoms and molecules, ions, radicals, photons, etc, the chemistry is very complex. A very selective product from this plasma chemistry could become very expensive. This character determines that nonthermal plasma is feasible for the synthesis of liquid fuel that is a mixture of higher hydrocarbons. Here we report a direct liquid fuel synthesis from the combination of conversions of coal and methane using dielectric-barrier discharge (DBD) that has led to a significantly high yield of higher hydrocarbons.
The temperature of all the reactions was adjusted at about 65 C with circulating oil. All the experiments were operated at atmospheric pressure.
The product from such DBD plasma methane conversion in the presence of coal contains gaseous hydrocarbons ... and syn-crude. It is clear that the product includes products from the decomposition of methane, products from the conversion of coal and products of reactions of discharge species with components in the coal. The decomposition of methane leads to the formation of higher hydrocarbons. The
conversion of coal principally leads to the formation of aromatics and also higher hydrocarbons (from the hydrogenation of coal).
The chain reactions lead to the formation of syn-crude. In the presence of coal, the components in the coal will also involve in the chain growth reactions for the syn-crude production to lead to the production of aromatics and nitrogen-containing hydrocarbons.
The present investigation has confirmed a syn-crude production from the combined conversions of methane and coal. Such produced syn-crude contains a large amount of branched higher hydrocarbons.
Compared to methane conversion in the absence of coal, the addition of coal in the discharge gap induces a significantly higher yield (more than 200% higher) of liquid fuel (syn-crude exactly). This means that the addition of coal is favoured for the syn-crude formation under the condition of DBD plasmas. This enhanced yield would be from the hydrogenation of coal (there is a plentiful of hydrogen species in the methane DBD plasmas). Since DBD plasma is a cold plasma phenomenon and can be operated at the ambient conditions, it is very potential to develop such combined conversions of coal and methane."
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As we have earlier reported from other sources, the "plentiful ... hydrogen ... in the methane" serves to improve the "hydrogenation" of highly-carbonaceous coal into liquid hydrocarbons. And, we can manufacture Methane by the Sabatier processing of Carbon Dioxide and the hydro-, or steam-, gasification of Coal.
Moreover, other work, which we will cite in future reports, further documents that Carbon Dioxide alone, absent syngas from Coal, can be recycled in very similar DBD plasma reactions, and, similar to Penn State University's process of "Tri-reforming", combined with Methane to synthesize higher hydrocarbons.
