Purity, carbons

The carbon monoxide purity from the Cosorb process is very high because physically absorbed gases are removed from the solution prior to the low pressure stripping column. Furthermore, there is no potential for oxidation of absorbed carbon monoxide as ia the copper—Hquor process. These two factors lead to the production of very high purity carbon monoxide, 99+ %. Feed impurities exit with the hydrogen-rich tail gas therefore, the purity of this coproduct hydrogen stream depends on the impurity level ia the feed gas. 

Silicon is the second most abundant element in the Earth s crust. It occurs widely in rocks as silicates, compounds containing the silicate ion, Si032, and as the silica, Si02, of sand (Fig. 14.33). Pure silicon is obtained from quartzite, a granular form of quartz (another solid phase of SiOz), bv reduction with high-purity carbon in an electric arc furnace ... 

At the Coal Research Establishment of the National Coal Board, methods for the liquefaction of coals to produce transport fuels, feedstocks for the chemical industry and high purity carbons suitable for electrode manufacture are being developed. 

The high purity carbon nanotubes (CNTs) used in this study were obtained by decomposition of acetylene over a powdered CoxMgi xO solid solution catalyst [19]. Different proportions of CNTs from 15 to 70% and polyacrylonitrile (PAN, Aldrich) have been mixed in an excess of acetone to obtain a slurry. After evaporation of acetone, precursor electrodes were formed by pressing the CNTs/PAN mixture at 1-2 tons/cm2. The C/C composites were formed by carbonisation of the pellets at 700-900°C for 30-420 min under nitrogen flow [20], The optimal capacitance properties of the composite were obtained for a mixture CNTs/PAN (30/70 wt%) treated at 700°C. Such C/C composite remains still quite rich in nitrogen (9 at% of N) demonstrating that PAN is an efficient nitrogen carrier. On the other hand,... 

Preparation,—In a state of purity, carbonate of soda iB most conveniently prepared from the bicarbonate. To obtain it, the latter salt is washed with cold water until the filtrate, after being acidified with nitric acid, is not rendered turbid by chloride of barium or nitrate of silver. The washed salt is then dried, and by gentle Ignition one half of thB carbonic acid is expelled, and the pure neutral carbonate remains. 

Photoisomerizations were carried out using a 450 watt Hanovia medium pressure mercury source, and each reaction was followed to the photo-stationary state by gas chromatographic determination of the cis/trans ratios. Twice recrystallized trans-stilbene (Aldrich), spectrophotometric grade cyclohexane, and dry, high purity carbon dioxide were used in these experiments. 

Kumar, R., Kratz, W. G, Guro, D. E., and Golden, T. G, A new process for the production of high purity carbon monoxide and hydrogen, Presented at the Int. Symp. On Separation Technology, Univ. Of Antwerp, Belgium (Aug. 22-27,1993). 

High purity carbon monoxide High purity hydrogen Ratio-adjusted synthesis gas... 

In the cryogenic partial condensation process, the feed gas is cooled to 85 K, which condenses the bulk of the carbon monoxide and methane. Uncondensed hydrogen-rich gas is cooled further to 70 K to liquefy additional carbon monoxide. These liquid fractions are degassed and then warmed to obtain high-purity carbon monoxide gas. A cryogenic distillation process can produce ul-trapure carbon monoxide. 

High-purity carbon monoxide (>99.8%) can be obtained in the liquid methane wash process, where the inlet gas is cooled to about 90 K and the bulk of the carbon monoxide is removed by condensation. The hydrogen-rich stream is washed in a column with methane, which absorbs carbon monoxide and other gases. Carbon monoxide is recovered from this solution in a fractional distillation column. 

Coke is employed for a number of purposes, but the major use is in the manufacture of carbon electrodes for aluminum refining that requires a high-purity carbon— low in ash and sulfur free. In addition, petroleum coke is employed in the manufacture of carbon brushes, silicon carbide abrasives, and structural carbon (pipes, Rashig rings, and so on), as well as calcium carbide manufacture from which acetylene is produced. 

Ammonia production consumes hydrogen that is obtained from synthesis gas after separating carbon dioxide. However, ammonia plants in the United States produce about 6.8 million tons of carbon dioxide per year, and urea and methanol plants only consume 4.0 million tons per year. This leaves an excess of 2.8 million metric tons of high-purity carbon dioxide per year that is vented to the atmosphere in the United States as shown in Table 1. 

Also, there is approximately another 19 million metric tons of relative high-purity carbon dioxide from refineries and other chemical plants in the United States that use hydrogen from synthesis gas and discharge carbon dioxide to the atmosphere. 

In the chemical production complex in the lower Mississippi River corridor shown in Fig. 3, there are about 150 plants that consume 1.0 quad (lO BTU/yr) of energy and generate about 215 million pounds of pollutants per year. There is a carbon dioxide pipeline that connects plants. Currently, there is approximately an excess 1.0 million metric tons of high-purity carbon dioxide per year from ammonia production that is being vented to the atmosphere. The cost of carbon dioxide as a raw material is essentially the pumping cost to a plant, about US 2-3 per metric ton. ... 

As carbon source, high-purity carbon black is mostly used and, more rarely, graphite, due to its higher price and lower reactivity. Thermal carbon black is preferred to flame... 

The SFC pump is shown connected to a high pressure cylinder. The simplest approach is to use high-purity carbon dioxide and a dip tube ... 

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