Ammonia stream

Fig. 62. Apparatus for preparing ammonia (a) and apparatus for purifying ammonium iodide by sublimation in an ammonia stream (6)...

Open the gas meter cock and, without stopping the ammonia stream, again bring an ignited splinter to the mouth of tube 1. What do you observe now Write the equation of the reaction. 

Preparation of Chromium(III) Nitride. Work in a fume cupboard Assemble an apparatus for preparing nitrides (see Fig. 84). Put 0.5-1 g of anhydrous chromium(III) chloride into a boat. Put the latter into a tubular furnace. Displace the air from the apparatus with a stream of dry ammonia and then heat the furnace to 600 °C. Continue the heating in an ammonia stream for one hour, next switch off the furnace and cool the apparatus without stopping the stream of gas. Extract the boat and weigh the product. Write the equation of the reaction. Calculate the yield in per cent. 

Preparation of Copper(II) Nitride. Assemble an apparatus (see Fig. 84). Use an electrical furnace to heat reaction tube 8. Put 2 g of copper(II) fluoride into porcelain boat 7 and place the latter into the reaction tube of the apparatus. Pass a stream of dry ammonia through the apparatus. Switch on furnace 6 and in half an hour the furnace used to heat tube 8, heating the latter to 280 °C. Why should not the temperature be increased above 300 °G When the reaction terminates (how can you determine this ), cool the apparatus in an ammonia stream. Put a small part of the product into a test tube and... 

The catalyst was placed in the reactor and held by two small plugs of quartz wool. Prior to the reactions, the catalysts were heated in a helium stream (60 ml/min) at 450°C for 30 min and then heated in an ammonia stream at the reaction temperature for 30 min. The reaction temperature was measured by a chromel-alumel thermocouple placed adjacent to the catalytic zone of the reactor. For each pulse, 5 p of the reactant (chlorobenzene or benzaldehyde) were injected by a microsyringe. 

To calculate the logarithmic-meaii temperature difference, the terminal temperatures of the condenser must be fixed. Because the condensation is essentially isobaric, the inlet and outlet ten eratures of the ammonia stream are 41.4°C (106.5 °F). From Table 4.1, the inlet cooling-water temperature is 30°C (86.0 °F) if cooling-tower water is used. Also, for thermodynamic considerations the exit water temperature must be less than 41.4°C, and it is calculated from Equation 4.7.6. If the lower value of the approach tenqjerature difference of 5 C (9.0 °F) is selected from Table 4.4, a low cooling-water flow rate will be needed. Thus, exit water temperature is 36.4°C. Therefore, from Equation 4.7.5, the logarithmic-mean temperature difference,... 

For this proposed design, 4500 kg/h of ammonia vapor at 6.7 bara pressure is to be cooled from 120°C to 40°C, using cooling water. The maximum supply temperature of the cooling water available is 30°C, and the outlet temperature is to be restricted to 40°C. The pressure drops over the exchanger must not exceed 0.5 bar for the ammonia stream and 1.5 bar for the cooling water. 

An absorber is to recover 99 percent of the ammonia in the. air-ammonia stream fed to it, using water as the absorbing liquid. The ammonia content of the air is 20 mole percent. Absorber temperature is to be kept at 30°C by cooling coils the pressure is 1 atm. (fl) What is the minimum water rate (6) For a water rate 40 percent greater than the minimum, how many overall gas-phase transfer units are needed ... 

N4H4 is made by simple metathetic reaction in liquid, solid, or gaseous media which may involve distillation or precipitation. For example, equimolar amounts of ammonium chloride and sodium azide may be distilled with an equal quantity of water. At 160°C pot temperature, the product volatilizes with water vapors and solidifies in the condenser tube which should, therefore, be at least 1 inch wide [305]. Equally clean and safe is a gas-phase reaction which requires, however, the preparation of hydrazoic acid gas. The reaction takes place in a long, 1-inch-wide glass tube which has two inlet tubes with orifices 20 inches apart, and a vent. The HN3 gas, carried with nitrogen, and excess ammonia stream in and precipitate the product as fine needles [39]. N4H4 is also precipitated when ammonia gas is bubbled into an ethereal hydrazoic acid solution [86]. The product stays in solution when HN3 vapors, carried with nitrogen, are bubbled into aqueous ammonia [306]. 

De Pasllle reconmiends that ammonium arsenate be reduced in an ammonia stream at 1000°C. According to Geach, very pure As can also be obtained by reduction of chemically pure AS3O3 with Zr metal and subsequent sublimation. Impurities other than Sb can be removed by sublimation in vacuum (Geach). 

At this stage in process synthesis, it is desired to determine, by the Cl method, the minimum amount of chilled methanol required for a MEN involving these four streams, noting that it may be possible to eliminate the need for chilled methanol. In the solution below, the COG and lean gas streams are first matched with the aqueous ammonia stream. Alternatively, it may be preferable to consider first matches with the chilled methanol stream. 

In the pipe-cross reactor, as in the T-reactor, ammonia enters tile pipe along the horizontal axis and phosphoric acid enters at right angles. There is, however, an additional inlet directly opposite the phosphoric acid inlet, through which another feed can be added at a right angle to the ammonia stream. This arrangement was developed to allow sulfuric acid to be added to the lEactim mixture. 

The stripper bottoms, at nearly 200°C, can be a valuable source of heat. First, it can be interchanged with a dilute ammonia stream (carrying the anunonia fix>m the scrubber bottoms) that is being recycled to the stripper column. Then, it is flashed at a positive pressure of about 1 atm to generate some of the steam used in the feed ammonia and caustic preheaters. The resulting solution will contain 2.3-2.5% NaOH at a temperature of about 125°C. It is a waste stream from the process. In some cases, it has served as a source of OH for the chemical treatment of brine. 

A stream of dry ammonia was passed through the tube during the preparation. After the zirconium tetrachloride was left for an hour in the stream at room temperature, the temperature of the furnace was raised to 350 C and kept at this temperature for an hour to obtain a-ZrNCl. Then, the temperature was raised again to 450 C and kept for an hour. Finally, the product was allowed to stand at 650 C for five hours in the ammonia stream in order to convert a-ZrNCl to 3 ZrNCl. Fine powder 3 ZrNCl crystals of a pale yellow-green color were obtained. 

Likewise we pass ammonia through the melter. We condense ammonia vapor to form liquid ammonia, which releases heat. We must choose a temperature greater than 0°C for the ammonia stream. We arbitrarily choose 32°C. A handbook reveals that the saturation pressure for ammonia at 32°C is 12.2 atm and A/fyap = 488.5 Btu/lb,... 

The sensitivity to corrosion of stainless steels can be reduced by adding a certain amount of the so-called passivation air to the carbon dioxide or ammonia stream to maintain a minimum oxygen concentration in the synthesis system. The oxygen... 

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