Washing carbon

The hydrogen manufacture process is relatively clean. In the steam reforming subprocess a potential waste source is the desulfurization unit, which is required for feedstock that has not already been desulfurized. This waste stream contains oil, sulfur compounds, and phenol. In the partial oxidation subprocess, free carbon is removed by a water wash. Carbon dioxide is discharged to the atmosphere at several points in the subprocess. 

This process can be illustrated by connecting an apparatus, A, for generating ammonia, Fig. 65, and an apparatus, B, for making washed carbon dioxide with a tower, O, filled with a sat. soln. of sodium chloride and fitted with four perforated iron discs as shown in the diagram. The tower is provided with an exit tube dipping in a beaker of water. The soln. is first sat. with ammonia, and then with carbon dioxide. In about an hour, crystals of sodium bicarbonate will be deposited on the perforated shelves. 

MgO-supported carbon catalyst was also prepared by impregnating an aqueous magnesium sulfate solution. The dried impregnated carbon was washed with concentrated ammonium hydroxide solution to convert the sulfate into magnesium hydroxide. This washed carbon was dried and heated in a tubular reactor as just described to convert the hydroxide to oxide. 

The washed carbon cake on which the capreomycin is adsorbed is washed with 200 L of 0.05 N aqueous hydrochloric acid. The acid wash is discarded. The washed carbon cake is eluted during a one-hour period with 400 L of an aqueous acetone containing 1.65 L of 11.7 N hydrochloric acid and 80 L of acetone. The filter cake is further eluted by washing the cake with 200 L of an aqueous acetone containing 825 ml of 11.7 N hydrochloric acid and 40 L of acetone during a 15-minute period. The combined eluates, having a total volume 575 L, are concentrated in vacuo to 52.5 L. The concentrate is added... 

Figure 2. X-ray diffraction patterns of samples 2a - initial catalyst, 2b - catalyst with formed on it carbon nanostructures, 2c - washed carbon nanostructures.

Synthesis gas may be prepared by a continuous, noncatalytic conversion of any hydrocarbon by means of controlled partial combustion in a fire-brick lined reactor. In the basic form of this process, the hydrocarbon and oxidant (oxygen or air) are separately preheated and charged to the reactor. Before entering the reaction zone, the two feed stocks are intimately mixed in a combustion chamber. The heat produced by combustion of part, of the hydrocarbon pyrolyzes the remaining hydrocarbons into gas and a small amount of carbon in the reaction zone. The reactor effluent then passes through a waste-heat boiler, a water-wash carbon-removal unit, and a water cooler-scrubber. Carbon is recovered in equipment of simple design in a form which can be used as fuel or in ordinary carbon products. 

When adsorption is finished, one washes carbon with 15 liters of distilled water until one cannot detect any more, in the filtrate, of water soluble impurities, and then one subjects this coal to an elution with 50 liters of methanol added with 10% of concentrated ammonia. The eluate is concentrated to 1 liter under 20 torr at 30° and the acid carboxylic, which crystallized at the end of twenty-four hours, is dried under 1 torr at 80°. The recovery is 45.3 grams is 91% of the theoretical quantity. 

Because complexation with Ca2+ results in insoluble CaCC>3, which deposits on items being washed, carbonate alone is not an effective builder system. In contrast, tripolyphosphate forms a soluble calcium salt, preventing deposition of insoluble salts. Sodium sesquicarbonate (Na2CC>3 NaHC03 -2 0) and sodium bicarbonate (NaHCCb) have not been used in LADD formulations, except where buffering action is needed. 

Pyrimidine-4,5-diamine (11 g, 0.1 mol), ethyl 2-ethoxy-2-hydroxyacetate (20 g, 0.13 mol) and 2M H2S04 (80 mL) were mixed and kept at 37 °C for 5 d. The dark solution was treated with acid-washed carbon (1 g) and filtered. The filtrate was adjusted to pH 5.5 using sodium citrate (10 g) and 10 M NaOH (approx 11 mL). A precipitate formed which was collected by filtration, refluxed with H20 (100 ntL), filtered hot, then recrystallized (boiling H20) yield 1.26g (85%) mp >240°C (dec.). 

Iron The concentration of iron ranges from traces to over 1 per cent. In carbons prepared by steam-activation, iron may be present in a magnetic state, and some of it can be removed by a magnet. Acid-washed carbon can contain iron in both ferric and ferrous forms. Iron is seldom released from a carbon except in solutions having a low pH. Actually most types of carbon can remove much iron from a solution having a pH of 4 or higher. 

Some of the iron in carbon can be removed by washing with acid or by electrolysis, but complete removal is seldom if ever accomplished, because iron salts are so strongly held by carbon and only a small portion is released with each extraction. Therefore a washed carbon can release some iron to acids such as citric, tartaric, hydrochloric. For applications in which the release of iron is objectionable it may be necessary to use a carbon prepared from source materials that are low in iron, or else take supplementary measures to remove the dissolved iron from the carbon treated product. 

Different lots of commercially available, steam-activated and HNO3 washed carbons from beechtree wood were used as catalyst support. Tremendous catalytic activity variations were still found after impregnation with a H2PdCl6-solution using the low pressure hydrogenation of cinnamic acid to dihydrocinnamic acid as a model reaction /5/. 

Particulates are removed from the gas by means of a two-stage water wash. Carbon formed in the partial oxidation reactor is removed from the system as a carbon slurry together with the a.sh and the process condensate. This slurry is. sub,sequently processed in the ash removal unit (f) described below. The product synthesis gas leaves the... 

Figure 5. Photoacoustic FT-IR spectrum of a methanol washed carbon fiber/polyimide matrix composite (13).

Castings are produced by different molding processes green sand, air-set sand, resin-bonded sand, rammed graphite, investment, etc. The corrosion resistance of an as-cast surface is a function of the moulding process, pouring temperature, and mold surface treatments or mold washes. Carbon pick-up and mold reactions are just two of the factors that influence corrosion resistance. The corrosion resistance of most machined surfaces will be independent of the molding process provided that 1/16-1/8 in. of material is removed. 

Dissolve the mixture in dilute (2N) sodium hydroxide solution and pass in water-washed carbon dioxide for 15-30 minutes. The phenol may then be removed by filtration and/or ether extraction. Wash the predpitate or the extract with saturated sodium bicarbonate solution, then with water before drying. Addify the alkaline residue and remove die add as desoibed in (a) 113). (Some... 

Fatty alcohol ethoxylates are used in washing, carbonizing and bleaching of wool. 

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