http://www.coalinfo.net.cn/coalbed/meeting/2203/papers/coal-mining/CM037.pdf
To follow up on our earlier report of Swiss and Chinese joint development of Dielectric Barrier Discharge plasma conversion of Methane, and Coal-derived synthesis gas, into higher hydrocarbons, we wanted to illustrate that there are other ways to approach the synergistic co-conversion of Coal and Methane.
Herein, we present, with comment appended, excerpts from:
"PRODUCTION OF SYNGAS BY METHANE AND COAL CO-CONVERSION IN FLUIDIZED BED REACTOR
Jinhu Wu, Yitain Fang, Yang Wang
Institute of Coal Chemistry, Chinese Academy of Sciences: People Republic of China
Abstract
In this paper we report the concept of coal and natural gas co-conversion operations in a fluidised-bed reactor, which was conceived by the Institute of Coal Chemistry, Chinese Academy of Sciences (ICCCAS). Based on the features of natural gas reforming and steam gasification of coal, it was suspected that the partially reacted coal char might exert a catalytic effect on the partial oxidation of the gas. This may ... (eliminate) ... the use of the expensive metal catalyst commonly used for gas reforming. The feedstock of methane needs not to be treated specially, which is most important for drainage-methane utilization because its small quantity oxygen content makes it difficult to concentrate methane. This would enable effective utilization of coal-bed methane, drastically reducing the environmental impact of coal mining and
enhancing the utilization of available resources. In addition, the integrated coal gasification and gas reforming offers a further advantage that the H2/CO ratio in the syngas produced can be adjusted ... .
The preliminary experiments in a laboratory-scale fluidized-bed reactor has proven the concept to be feasible, achieving over 90% natural gas conversion with favourable quality of the syngas produced ... .
The production of syngas from fossil fuel is the first step of chemical synthesis. Nowadays the dominant syn-gas production process is coal gasification and methane reforming. From the component point of view, coal contains more carbon and less hydrogen, methane contains more hydrogen and less carbon ... the H2/CO ratio in the syn-gas from methane is much higher than from coal. But when considering downstream synthesis, different desired products require different H2/CO ratio in the syn-gas ... .
Till now, steam reforming is the most mature and widely used technology for methane-based syn-gas production. But this process exists some unavoidable drawbacks. ... the H2/CO ratio in the syngas is ...
normally too high compared with what is required by many downstream synthesis processes. To avoid carbon deposition on the catalyst, excess steam more than the stoichiometry reaction required must be employed. This causes higher operation cost. In addition, the reactor of high temperature tubular heat exchanger is inefficient and very expensive for its material and manufacture.
In recent years, a lot of attention has been paid on CO2 reforming because it has the potential advantages of lower theoretical H2/CO ratio and reuse of CO2 ... .
The CH4 partial oxidation reforming ... yields syn-gas ... (suitable) for many downstream synthesis. There are 2 ways to reforming CH4 to syn-gas, namely non-catalytic and catalytic process. The non-catalytic process has been commercialized. It is operated under the conditions of 30-100 atm and around 1573K. So high temperature means higher operation cost. On the contrary, the catalytic process can be operated under lower temperature. Because of efficiency and economics, it has been considered to be the most promise CH4 reforming process in the future.
In this paper we report the concept of coal and natural gas co-conversion operations in a fluidized-bed reactor ... . Based on the features of natural gas reforming and steam gasification of coal, it was suspected that the partially reacted coal char might exert a catalytic effect on the partial oxidation of the gas ... . This may be best effected in a fluidized-bed reactor ... , eliminating the use of the expensive metal catalyst commonly used for gas reforming. Based on this idea, some preliminary tests were carried out in a lab-scale fluidized bed reactor. Some typical results of pure methane-coal and simulated coal mine drainage-methane are introduced, which proved the concept to be feasible.
Besides natural gas, there are also other gases that contain rich methane, such as coke oven gas, coal bed methane and coal mine drainage gas.
(Note the mention of "coke oven gas", and recall some of our earlier reports documenting it's potential for use in conversion processes leading to liquid hydrocarbon fuels. - JtM)
The preliminary experiments in the laboratory-scale fluidized-bed reactor have proven the concept to be feasible. Under moderate temperature ... it achieves enough methane conversion ... with favorable quality of the syngas produced ... , eliminating the use of the expensive metal catalyst commonly used for gas reforming. The feedstock of methane needs not to be treated specially ... (and) the integrated coal gasification and gas reforming offers a further advantage that the H2/CO ratio in the syngas produced can be
adjusted by varying the ratio of coal/gas in the feedstock, to tailor the syngas to suit downstream processing requirement."
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In the body of the text, they refer mostly to recovered "coal bed" methane as a resource to employ in these co-conversion technologies. Although that is certainly a good use for a potentially "lost" resource, a supposed greenhouse pollutant, we submit that a better way to obtain the Methane would be through the Sabatier recycling of Carbon Dioxide; or, through the hydrogasification of Coal.
Either way, Methane can then be combined with Coal-derived synthesis gas to improve and maximize the subsequent production of liquid hydrocarbons.
