Gas stripping technique

In summary, the important equilibrium quantity is the ratio of the air and water concentration CpJC ff or HIRT, which is equivalent to ZJZ. H can be estimated as P /C in which the saturation vapor pressure P can be obtained experimentally or from literature data or from the normal boiling point. We can be obtain C experimentally or from literature data or from molecular surface area correlations. Alternatively, H can be measured directly by gas-stripping techniques. 

The procedure in an analytical scheme for the analysis of a wide range of organic compounds may be a combination of a gas-stripping technique for the volatiles and a number of adsorption or extraction steps. Alternatively, the sample can be passed through an adsorbent resin. The organics that pass the resin can be isolated from the effluent by means... 

Non-destructive partial stripping techniques for basic dyes on acrylic fibres are carried out at 100 °C (or higher if possible) using, for example, 1-10% o.w.f. anionic retarder and 1 g/1 acetic acid (60%), or 1-5 g/1 Marseilles (olive oil) soap. Destructive stripping requires acidified (pH 5.5-6.0) sodium hypochlorite, followed by an antichlor treatment in sodium dithionite or sodium bisulphite. In some cases a preliminary boiling treatment in 5 gA monoethanolamine and 5 g/1 sodium chloride is said to improve the effect of the stripping treatment. 

Grob and Zurcher [36,53-55] have carried out very detailed and systematic studies of the closed loop gas stripping procedure and applied it to the determination of parts per billion of 1-chloroalkanes in water. Westerdorf [56] applied the technique to chlorinated organics and aromatic and aliphatic hydrocarbons. 

Grob et al. [220-223] have carried out very detailed and systematic studies of the closed-loop gas stripping procedure and applied it to the determination of xg/l of 1-chloroalkanes in water. Westerdorf [224] applied the technique to chlorinated organics, and aromatic and aliphatic hydrocarbons. Waggot and Reid [225] reported that a factor of major concern in adapting the technique to more polluted samples is the capacity of the carbon filter, which usually contains only 1.5-2 mg carbon. They showed that the absolute capacity of such a filter for a homologous series of 1-chloro-n-alkanes was 6 xg for complete recovery. 

Ezeji, T.C., Qureshi, N. and Blaschek, H.P. 2004. Acetone Butanol Ethanol (ABE) Production from Concentrated Substrate Reduction in Substrate Inhibition by Fed-Batch Technique and Product Inhibition by Gas Stripping. Appl. Microbiol. Biotechnol., 63,653-658. 

As in the convention techniques, urea is produced at about 180 to 7XXPC. On the other hand, the residual carbamate is decomposed at the synthesis pressure, by reducing its partial pressure by means of gas stripping. The recombination of the reactants thus liberated occurs alter their condensation, by passage in an absorber or a scrubber, which also serves to recondense the fractions vaporized during the reaction, and to achieve recycling entirely in liquid form. To minimize corrosion problems, the different effluents are normally caused to flow by gravity, or by vaporization, or even by means of ejectors. 

Montedison, which originally participated in the Momecaiini-Fauser joint venture to market a number of total-recycle variants, and now presents its IDR (Isobaric Double Recycle process) technique. TTiis process operates at 20.10 Pa absolute, around 190 to 200, with an N/C ratio of4 to 5 in the reactor. Unconverted carbamate is decomposed in two successive gas stripping steps, one with ammonia, and the second with CO 2. in the pressure conditions of urea s nthesis, i.e.. 10 Pa absolute. 

Sodium carbonate is a less costly absorbent, but also less efficient. Other acid gas removal techniques use physical absorption of carbon dioxide in organic solvents, such as the dimethyl ether of polyethylene glycol, or methanol (the Selexol or Rectisol processes). For effective absorption these require high gas pressures. Regeneration of solvent is done by pressure letdown plus some air stripping (sparging of air through the solvent). 

Platinum and suitable reference electrodes are relatively easy and inexpensive to construct, but the measurement technique may significantly alter measured voltages. Quantification of H2 may be more reliable than Eh measurements for identifying anoxic redox process. Quantification of H2 may be achieved by using a gas-stripping procedure by N2 displacement following sample collection (Chapelle etal. 1996). However, because of complexities in interpretation,... 

Sirotherm resins tend to be slowly oxidized by dissolved oxygen in raw water at the elevated temperature of regeneration223 240 this may be controlled by vacuum deaeration or by other techniques, such as natural gas stripping or combined coagulation and deaeration by ferrous ion. 

Numerous endeavors have been implemented in fermentation process development in order to alleviate the solvent-induced inhibitory effects and thus improve the fermentation productivity. Usually, the selective removal of fermentation products was integrated simultaneously into the fermentation process in order to maintain a low solvent concentration in the fermentation broth. Many online butanol removal techniques have been reported with various advantages and efficiencies, including liquid-liquid extraction, perstraction, gas stripping, pervaporation, adsorption, reverse osmosis, etc. 

Ezeji TC, Qnreshi N, Blaschek HP. (2004). Acetone bntanol ethanol (ABE) production from concentrated snbstrate reduction in snbstrate inhibition by fed-batch technique and product inhibition by gas stripping. Appl Microbiol Biotechnol, 63, 653—658. 

---