Ammonia separation process

Sodium bicarbonate precipitates from solution and is recovered by filtration. Ammonium chloride is then crystallised from the filtrate, separated, washed, and dried. The exact proportion of ammonium chloride recovered depends on the relative demands for sodium carbonate and ammonium chloride. If economic conditions requite, part of the ammonia can be recovered and returned to the hrine-ammoniation step by distillation of the ammonium chloride solution ia the presence of lime. The spent calcium chloride Hquor, a final product ia manufacture of sodium carbonate by the ammonia—soda process, can also be used to obtain ammonium chloride. This Hquor is treated with ammonia and carbon dioxide... 

The Rijnmond area is that part of the Rhine delta between Rotterdam and the North Sea. The Commission for the Safety of the Population at large (COVO) commissioned the study for six chemicals and the operations associated with them acrylonitrile, liquid ammonia, liquid chlorine, LNG, propylene, and part of a separation process (diethanolamine stripper of a hydrodesulfurizer). The study objectives were to evaluate methods of risk assessment and obtain experience with practical applications of these methods. The results were to be used to decide to what extent such methods can be used in formulating safety policy. The study was not concerned with the acceptability of risk or the acceptability of risk reducing measures. 

Sampling Procedure. The sample extraction technique previously described was used in this work (8). However, a heated palladium thimble was also used to separate hydrogen and hydrocarbon fractions of the samples. No exchange occurred during the separation process in agreement with observations of other workers (30). In experiments using NH3 as a minor additive, the ammonia fraction was separated by means of appropriate cold traps. 

In principle, the calculation of concentrations of species of a complexation equilibrium is no different from any other calculation involving equilibrium constant expressions. In practice, we have to consider multiple equilibria whenever a complex is present. This is because each ligand associates with the complex in a separate process with its own equilibrium expression. For instance, the silver-ammonia equilibrium is composed of two steps ... 

In the production of ammonia from hydrogen and nitrogen the conversion, based on either raw material, is limited to 15 per cent. The ammonia produced is condensed from the reactor (converter) product stream and the unreacted material recycled. If the feed contains 0.2 per cent argon (from the nitrogen separation process), calculate the purge rate required to hold the argon in the recycle stream below 5.0 per cent. Percentages are by volume. 

Cellulose is itself polar in nature and can cause some adsorption, which may result in the tailing of zones. However, this adsorptive effect may contribute to the separation process in some instances and the use of a polar mobile phase can enhance this effect further, e.g. the separation of amino acids using an aqueous solution of ammonia as the mobile phase. The combination of partition and adsorption generally influences separations on cellulose thin-layer plates, which have superseded paper chromatography in most instances and offer increased speed and resolution. 

Many of the undesirable substances present in gaseous or liquid streams form volatile weak electrolytes in aqueous solution. These compounds include ammonia, hydrogen sulfide, carbon dioxide and sulfur dioxide. The design and analysis of separation processes involving aqueous solutions of these materials require accurate representation of the phase equilibria between the solution and the vapor phase. Relatively few studies of these types of systems have been published concerning solutions of weak electrolytes. This paper will review the methods that have been used for such solutions and, as an example, consider the alkanolamine solutions used for the removal of the acid gases (H2S and C02) from gas streams. 

The same technique has been employed for the purification of Food Colour Red No. 106 (Acid red). The chemical structure of the dye is shown in Fig. 3.118. The separation process was controlled by analytical RP-HPLC carried out in an ODS column (150 X 4.6 mm i.d. particle size 5 /.an). The mobile phase consisted of ACN-0.01 M TFA (27 73, v/v). The flow rate was 1 ml/min and analytes were detected at 254 nm. Equilibrated n-butanol and water were employed for CCC separation. OP was acidified with 40 mM of sulphuric acid, and 30 mM of aqueous ammonia was added to the LP. The coil was rotated at 800 rpm and LP was pumped at a flow rate of 1 ml/min. Fractions of 1 ml volume were taken from the effluent. The CCC profile of Food Colour Red No. 106 in CCC is shown... 

Hydrotreating generates sour wastewater from fractionators used for product separation. Like most separation processes in a refinery, the process water used in fractionators often comes in direct contact with oil and thus can be highly contaminated. It also contains hydrogen sulfide and ammonia and must be treated along with other refinery sour waters. In hydrotreating, sour wastewater from fractionators is produced at the rate of about I.O gallon per barrel of feed. 

In the DSN process, nitrogen tetroxide, N2O4 obtained from ammonia oxidation is absorbed by concentrated nitric acid in the presence of air or oxygen to yield pure nitric acid. Alternatively, N2O4 may be separated from the product gases of the ammonia oxidation process by refrigeration and then is treated with dilute nitric acid in air or oxygen. 

Fig. 8. Ammonia and boric acid concentrations of the fluids delivered from the same well at different times (between August 1983 and April 1985). The composition of the re-injected waters (squares) and steam produced before re-injection (black dots) are reported with the variations expected by a single-stage separation process. Two groups of isotherms at 200, 240, and 280 C ate drawn starting from two average values of the chemical composition of waste waters injected at different times.

Thus, after a good deal of complicated aqueous chemistry, we have separated Cu, Ni, and Co ions from one another. Reduction of the ions to the metals is described in Section 17.6. A more recent version of the ammonia leach process uses an ammonia/ammonium carbonate, rather than sulfate, buffer solution. 

ENSORB [ExxoN adSORB] A process for separating linear from branched hydrocarbons, using a zeolite molecular sieve. The adsorbed gases are desorbed using ammonia. The process operates in a cyclic, not a continuous, mode. Developed by Exxon Research Engineering Company, and used by that company on a large scale at the Exxon refinery in Baytown, TX. 

The recovery process is a vapor phase fixed-bed adsorption technology featuring desorption with ammonia. This process has paraffins recovery and product purity in the high 90% s. Ammonia is a very efficient desorbent. Since it is easily separated from the n-paraffins product, fractionation capital and energy requirements are substantially reduced. Furthermore, ammonia has the added advantage of protecting the adsorbents from coking. 

LP mordenite doped with platinum is the catalyst used in the Shell Hysomer process for alkane hydroisomerization this can be linked to the Isosiv separation process whereby -/n-alkanes are separated on LTA zeolite. This link is the basis of the joint Shell/UOP Total Isomerization Process (TIP). Similar catalysts have been employed to hydrocrack (i.e. dewax) diesel fuels. There have also been reports of commercial use of mordenite to catalyze methanol amination with ammonia, to produce dimethylamine. 

Methanator m) C02 removal solvent boiler n) Process condensate separator o) C02 absorber p) Synthesis gas compressor q) Process air compressor r) Ammonia converter s) High-pressure ammonia separator 1) Ammonia and hydrogen recovery from purge and flash gas... 

The choice of H2S rather than H2 as the circulating gas, in spite of the fact that the latter would give much higher effective separation factors, is based on the fact that to date no stable effective catalysts have been found which will catalyze the H2-H2O exchange with liquid water. The use of water vapor as in the Barr type tower makes the H2-H2O process unfavorable compared to the H2S-H2O process. Only the ammonia-hydrogen process (5) catalyzed in the liquid phase by potassium amide has emerged as competitive with the H2S-H2O exchange. A full... 

Manufacture. Sodium carbonate is an important product of the alkali industry. It is obtained naturally by the purification of sal soda which is found in the water of lakes Magadi of Kenya in East Africa, Owens of California in the USA etc. Industrially it is obtained by the Solvay process (ammonia-soda process) sodium chloride solution is saturated by ammonia which is forced into the solution. Carbon dioxide gas is then blown into the solution to form the bicarbonate (NaHCO 3) and ammonium chloride (NH<,.C1). When the bicarbonate is separated and heated, water and carbon dioxide are driven off and sodium carbonate is obtained. The ammonium chloride is mixed with milk of lime and distilled to form calcium chloride and ammonia solution. The recovered ammonia is used repeatedly. 

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