SYNTHESISkiODKKN industry often automatically records pH. temperature, pressure, etc., for reasons of plant efficiency, and analysis of individual spot samples is commonly used in the control of an industrial process. W here process materials are gaseous or liquid, methods of continuous analysis are often possible, though these have not received the attention their importance justifies. Individual papers involving continuous analysis do not permit the analyst to include details which would enable readers to appreciate the over-all advantages and the limitations of continuous analysis.Jl is for this reason that we take particular pleasure in publishing the following seven articles on "Analyti-cal Control for Ammonia Synthesis", prepared by Karl H. Brown and co-workers at Tennessee Valley Authority, Wilson Dam, Ala. In these we have an excellent representation of development and application in this type of analysis for control of an important industrial process.Further, to illustrate the conventional approach of the analyst in the determination of a specific compound and the compromises needed to develop a procedure for continuous recording, two articles on determining methyl bromide in air follow immediately after the group of seven.h. T. H u,i.i:tt.
The iodine pentoxide reagent must completely oxidize low concentrations of carbon monoxide at comparatively low temperatures in the presence of about 75% hydrogen and in addition must maintain its activity for a long period. The following procedure, using reagent-grade chemicals, gives a reagent that has an active life of 30 to 40 days.Seventy grams of calcined, crushed insulating brick (Armstrong A-25; -9+14 mesh) are added to a solution containing 100 grams of iodine pentoxide and 4 grams of vanadium pentoxide.
An eleciroconductometric analyzer for the continuous determination of the carbon dioxide concentration in ammonia plant gases is described. The application of the results given by the analyzer to the operation of both the water and copper scrubbers of the gaspurification system of the TV A synthetic ammonia plant is given. The range of the analyzer described is 0 to 2%, but the analyzer is adaptable to other ranges. THE converted semi-water gas entering the purification system of the TVA ammonia plant consists of hydrogen and nitrogen in the ratio of 3 to 1, together with about 29% carbon dioxide, about 2% carbon monoxide,' and some inert gases (3). About 98% of the carbon dioxide is removed by scrubbing the gas with water, and the concentrations of both carbon dioxide and carbon monoxide are reduced to about 5 p.p.m. by scrubbing with ammoniacal copper solution. The analyzer described in this paper gives a continuous indication of the carbon dioxide content of the gas leaving the water scrubber.
DESCRIPTION AND OPERATIONThe analyzer consists of a gas-control train, an absorptionconductivity cell, and a recording alternating current Wheatstone bridge. The gas-control train is shown in Figure 1. The pressure stabilizer (1) gives a uniform operating pressure; the grooved stopcock and flowmeter are used to regulate the rate of gas flow; and the potassium hydroxide-Ascarite tube removes carbon dioxide from the gas when the recorder zero is being checked. The principle and operation of the absorption-conductivity cell and recording alternating current Wheatstone bridge have been described (2).The operating conditions for the determination of carbon dioxide in the range of 0 to 2% are: Electrolyte 0.04 Ar sodium hydroxide Electrolyte flow rate 15 ml. per minute Gas flow rate 8 liters per hour Cell temperature Constant ; between 28°and 32°C.
An electroeonductometric analyzer for the continuous, separate, or simultaneous determination of carbon dioxide and carbon monoxide in concentrations of 0 to 100 p.p.m. in hydrogen-nitrogen mixtures and the application of the analyzer to the analytical control of the TVA synthetic ammonia plant are described. An absorptionconductivity cell of new design and a recording alternating current Wheatstone bridge are employed. Carbon monoxide, after oxidation by an improved iodine pentoxide reagent, is determined as carbon dioxide. Full operating details are given.
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