Electric arc process

The first commercial attempt by Charles S. Bradley and D. R. Lovejoy, relying on power from a newly built Niagara Falls hydrostation, was launched in 1902. Their patented method produced more than 400,000 elongated electric arcs per minute inside a furnace made up of a fixed iron shell surrounded by a rapidly revolving cylinder. Nitrogen oxide generated from the passing air enriched with O2 was converted to nitric acid, but the operation was uneconomical and their Atmospheric Products Company folded in 1904.  

An alternating current arc was produced in the Birkeland-Eyde furnaces (their capacity rose eventually to 4 MW/unit) between water-cooled copper electrodes 

In all of these plants highly dilute oxides produced by sparking (the air leaving the chamber had just 1.5-2% NO by volume) had to be cooled rapidly (to 800-1000 °C) in order to prevent the reverse reaction converting the gas back to N2 and O2. Then the gases were cooled further and condensed to produce nitric acid, which was reacted with lime to yield calcium nitrate—Ca(N03)2, a compound with 17% N—which could be used directly as a fertilizer  

The process was highly energy-intensive its initial requirements were in excess of 700 MJ/kg N, while later its most efficient versions still needed between 50 and 75 kWh of electricity per kilogram of nitrogen, or 180-270 GJ/t N. By 1913 the an- 

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Electric arc process. Patented by Siemens in 1878, this u.ses an electric current through the metal (direct-arc), or an arc just above the metal (indirect-arc), as a means of heating. It is widely used in the manufacture of alloy- and other high-quality steels. 

The vision of the late W E Ballard ensured that this chapter is still very relevant but there have been some changes in emphasis. Of the spraying techniques, the electric arc process is now generally more economical in operation than oxy-fuel gas processes. The rate of spraying is proportional to the current used and several types of equipment are available ranging from 200 to 1 000 A capacity. For manual operation, pistols using currents up to... 

James, D. H., Thermal Spraying by the Electric Arc Process , Metallurgist and Materials Technologist, IS, 85-90 (1983)... 

Avco An electric arc process for making acetylene from coal and hydrogen. The arc in hydrogen is rotated by a magnetic field in order to spread it out and thus make better contact with the coal passing through. Developed by V. J. Krukonis at the Avco Corporation in the early 1970s with support from the U.S. Office of Coal Research Piloted at the rate of 55 kg/hr but not yet commercialized. 

Imatra Also called the Solid Lime Process. A method for desulfurizing steel made by an electric arc process. Additions are made of burnt lime (calcium oxide), fluorspar (mineral calcium fluoride), and ferro-silicon. 

Electric arc nitric acid processes, 77 186 Electric arc processes, of ammonia synthesis, 77 114-115 Electric-arc vaporizer zinc oxide process, 26 613... 

A technical exploitation of these experiments appeared unattractive, until 1909. Other methods of the chemical fixation of nitrogen, particularly the electric arc process for the formation of nitrous oxides (18) and the calcium cyanamide process (19) appeared far superior at that time. 

The Hiils electric arc process was the only large-scale process using plasma reactions where large quantities of carbon black were produced as a byproduct in the production of acetylene. Today, this kind of carbon black is no longer used as a pigment. 

Electric arc processes have been given a new lease on fife in the guise of plasma reactors, especially those involving cold, or nonthermal plasmas, with electron temperatures of I (E-IO5 K and gas temperatures of 102-103 K. Plasmas of this kind can be used to activate and functionalize inert molecules, but usually with only poor selectivities and low energy yields ( 0.01 mol/kWh ). The use of catalytic additives may offer some potential for improvement, but reactive plasma processes will probably remain restricted to a few specific applications. 

New spatial forms of carbon - fullerenes, nanotubes, nanowires and nanofibers attract significant interest since the time of their discovery due to their unique physicochemical and mechanical properties [1-3]. There are three basic methods of manufacturing of the carbon nanomaterials (CNM) - laser evaporation, electric arc process, and catalytic pyrolysis of hydrocarbons. However, the multi-stage manufacturing process is a serious disadvantage for all of them. For example, the use of organic solvents (benzol, toluene, etc.) for separation of fullerenes from graphite soot results in delay of the synthesis process and decrease in the final product quantity. Moreover, some environmental problems can arise at this. 

Table 5.4 shows the influence of electricity expenditures on the cost price of acetylene for the five main ocesses examined above. Among them, the electric arc processes and techniques based on calcium carbide are those that benefit most from the advantages of electricity, and guarantee some tsd ndence of the acetylene price from that of petroleuin products. 

A vast amount of research in all three directions led to commercial processes for each of them the electric arc process, the cyanamid process, and ammonia synthesis, which finally displaced the other two and rendered them obsolete. 

The methods for the synthesis of alkynes have been extensively reviewed in the past 20 years two books, which deal particularly with the preparative aspects of alkyne chemistry, have been published. Except for the syntheses of acetylene and propyne, which are prepared in technical processes from carbides, from methane by oxidation, or by electric arc processes, all carbon-carbon triple bonds must be generated by an elimination reaction. Again, as in the synthesis of alkenes, the most important is the de-hydrohalogenation. 

In the Chemische Werke Hiils electric arc process, acetylene is produced by pyrolyzing hydrocarbons with boiling points up to 200°C in an electric arc. Fine particulate carbon black is produced as a byproduct in such quantities that working up is worthwhile. 

Arc black i.s produced as a byproduct in the production of acetylene by the Hills electric arc process... 

Derivation Oxidation of ammonia above 500C, decomposition of nitrous acid (aqueous solution). Also from atmospheric oxygen and nitrogen in the electric-arc process for fixation of nitrogen. 

Raw material Basic Bessemer process Hot metal, fixed open hearth furnace Electric arc process Basic (LD) oxygen furnace... 

The first commercial processes used to produce ammonia were the cyanamide and electric arc processes at the beginning of the 20th century. The cyanamide... 

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