Oxygen from coal

The poor efficiencies of coal-fired power plants in 1896 (2.6 percent on average compared with over forty percent one hundred years later) prompted W. W. Jacques to invent the high temperature (500°C to 600°C [900°F to 1100°F]) fuel cell, and then build a lOO-cell battery to produce electricity from coal combustion. The battery operated intermittently for six months, but with diminishing performance, the carbon dioxide generated and present in the air reacted with and consumed its molten potassium hydroxide electrolyte. In 1910, E. Bauer substituted molten salts (e.g., carbonates, silicates, and borates) and used molten silver as the oxygen electrode. Numerous molten salt batteiy systems have since evolved to handle peak loads in electric power plants, and for electric vehicle propulsion. Of particular note is the sodium and nickel chloride couple in a molten chloroalumi-nate salt electrolyte for electric vehicle propulsion. One special feature is the use of a semi-permeable aluminum oxide ceramic separator to prevent lithium ions from diffusing to the sodium electrode, but still allow the opposing flow of sodium ions. 

Moles of Oxygen Removed From Coal Products Figure 3. Sensitivity of hydrogen consumption to oxygen removal... 

This is an oxygen-blown flow slagging gasifier first developed back in the 1970s by British Gas at the Westfield Development Center in Fife, Scotland, to produce SNG from coal. 

The Vision 21 program is focused on new concepts for coal-based energy production where modular plants could be configured to produce a variety of fuels and chemicals depending on market needs with virtually no environmental impact outside the plant s footprint. Membranes would be used to separate oxygen from air for the gasification process and to separate hydrogen and carbon dioxide from coal gas. 

If the temperature is further increased, e.g., beyond 700 °C, the C2 4 oxygenates further decompose to a mixed gas of moderate heating value, namely to a mixture of CO, C02, H2 and CH4. This gas resembles the town gas that was produced from coal at the beginning of the 20th century. Beyond 1000 °C, the hydrocarbons constituents of the mixed gas are further reformed, which results in the production synthesis gas, a valuable mixture of CO and H2 with some C02 and water as main contaminants. 

Gasification. The extent of carbon removal from coal by pyrolysis is relatively limited. As a result, the yields of secondary fuels having increased H/C ratio are not large. Essentially complete control of the amount of carbon removed can be achieved, however, by complete gasification of coal with an oxygen-containing gas and steam ... 

The hydroformylation of alkenes was accidentally discovered by Roelen while he was studying the Fischer-Tropsch reaction (syn-gas conversion to liquid fuels) with a heterogeneous cobalt catalyst in the late thirties. In a mechanistic experiment Roelen studied whether alkenes were intermediates in the "Aufbau" process of syn-gas (from coal, Germany 1938) to fuel. He found that alkenes were converted to aldehydes or alcohols containing one more carbon atom. It took more than a decade before the reaction was taken further, but now it was the conversion of petrochemical hydrocarbons into oxygenates that was desired. It was discovered that the reaction was not catalysed by the supported cobalt but in fact by HCo(CO)4 which was formed in the liquid state. 

In the late nineteenth century and up to World War II coal was the major starting material for the organic chemical industry. When coal is heated in the absence of oxygen, coke and volatile by-products called coal tars are created. All sorts of organic chemicals can be isolated from coal tar - benzene, toluene, xylenes, ethylbenzene, naphthalene, creosotes, and many others (including Hofmann and Perkin s aniline). The organic chemical industry also draws upon other natural products, such as animal fats and vegetable oils, and wood by-products. 

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