Free boiling

Neutralizers may be free-boiling vessels, circulating systems or pipe reactors. The water in the nitric acid is evaporated by the heat of reaction (550 to 620 BTU/lb of AN, depending on the acid strength). At least ten different types and designs of neutralizers are used in Europe. The factors that influence the choice of neutralizer are103 ... 

Bromide, (a) If iodide is present, this must be removed by treating one-third of the solution with 5 ml dilute H2S04 and 1 ml of 50 per cent KN02 solution (chloride-free). Boil the solution with stirring, concentrate to 3 ml and allow to cool. Test for bromide as under (Z>). 

Sugar-free boiled sweets Stabiliser A new use but as a minor ingredient. The high molecular weight of the gum prevents cold flow... 

Stock solution of RNase Dissolve 2 mg of DNase-free RNase A (Sigma) in 1 mL of distilled water. If RNase is not DNase-free, boil this solution for 3 min. Solutions 4-7 may be stored at 4 0C for several weeks. 

Typical vapour and liquid (T-x) curves under equilibrium (free boiling) and non-equilibrium... 

Deviation of vapour composition y(ll) from the free boiling value y(l) with increasing evaporative mass flux... 

Thus, for an LNG example, as a binary liquid mixture of 80 % methane and 20 % ethane [3], the vapour will possess a 98 % concentration of methane according to the free boiling (T-x) data. However, with surface evaporation only, the vapour composition will increase from 98 % towards 100 % methane from an 80 % liquid, as the evaporation rate increases (see Fig. 5.4). 

The consequences of surface evaporation (T-x) values being different to published free-boiling, equilibrium values, means that vapour compositions of LNG and LPG in storage tanks are not a good guide to their liquid phase compositions. See also the consequences of Marangoni film flows up the tank walls in Sect. 6.4.4. 

T-x) data for surface evaporation of LNG and LPG mixtures may not be the same as the (T-x) free-boiling data used for distillation. The deviation in vapour composition from the equilibrium data is proportional to the surface evaporation mass flux. 

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