Liquid absorber

Physical Properties. All colourless liquids, completely miscible with water, except benzyl alcohol and cyclohexanol, which are slightly soluble. Pure glycol and glycerol have high viscosity, which falls as the hygroscopic liquids absorb water from the air. 

Basically, a gas absorption tower is a unit in which the desirable light ends components are recovered from the gas feed by dissolving them in a liquid passing through the tower countercurrently to the gas. The liquid absorbent is called lean, oil, and it usually consists of a hydrocarbon fraction in the gasoline boiling range. After the absorption step, the liquid which now contains the desired constituents in solution is referred to as fat oil. A similarly descriptive nomenclature is applied to the gas, which is referred to as wet gas when it enters the tower and as dry gas when it leaves the absorber. 

XjR = Mols of a component in liquid absorbed per mol of lean oil entering column... 

This process selectively removes a certain gas from a gas mixture using a liquid absorbent. In the refining industry, this process is used extensively to free the product gas streams from acid gases (mainly H2S) either by using a physical or a chemical absorbent. Absorption of acid gases from natural gas are discussed in Chapter 1. 

Jean-Claude Charpentier, Mass-Transfer Rates in Gas-Liquid Absorbers and Reactors Dee H. Barker and C. R. Mitra, The Indian Chemical Industry-lts Development and Needs Lawrence L. Tavlarides and Michael Stamatoudis, The Analysis of Interphase Reactions and Mass Transfer in Liquid-Liquid Dispersions... 

To increase the permeability of a certain region of the reservoir, the liquid-absorbed water is evaporated by heating the portion to a temperature above the boiling point of water, taking into account the ambient pressure [897,1487]. The liquid water is evaporated by injecting a water-undersaturated gas, such as heated nitrogen, into the reservoir. 

Figure 227. Adsorption process of water vapor on solids Solid Adsorbent Liquid Absorbent...

The theory of sorption storage systems will be explained for solid adsorbents. The basic results can be transferred to liquid absorbents. 

Although the preceding processes described for C02 separation are based on liquid absorbent solutions operating at low (cold methanol) to moderate temperatures (hot carbonate), C02 may also be separated by solid sorbents, typically operating at high temperatures, for example, base metal oxide such as CaO (Fan et al., 2005 Harrison and Peng, 2003) can absorb C02 at 600°C temperatures by reversible carbonation/decarbonation reaction ... 

In this example, a fluidised biofilm sand bed reactor for nitrification, as investigated by Tanaka et al. (1981), is modelled as three tanks-in-series with a recycle loop (Fig. 1). With continuous operation, ammonium ion is fed to the reactor, and the products nitrite and nitrate exit in the effluent. The bed expands in volume because of the constant circulation flow of liquid upwards through the bed. Oxygen is supplied external to the bed in a well-mixed gas-liquid absorber. 

Chemical compatibihty/Stabihty considerations Syrupy liquid, absorbs moisture from air. Contact with strong oxidizing agents (such as potassium permanganate) may cause an explosion... 

Liquid absorbents. If the partial pressure of the water in the gas is greater than the equilibrium partial pressure at the surface of a liquid, condensation will take place as a result of contact between the gas and liquid. Thus, water vapour is frequently removed from a gas by bringing it into contact with concentrated sulphuric acid, phosphoric acid, or glycerol. Concentrated solutions of salts, such as calcium chloride, are also effective. The process may be carried out either in a packed column or in a spray chamber. Regeneration of the liquid is an essential part of the process, and this is usually effected by evaporation. 

Mass-Transfer Rates in Gas-Liquid Absorbers and Reactors Jean-Claude Charpentier The Indian Chemical Industry— Its Development and Needs... 

Sampling of these substances has been carried out following three approaches liquid absorbents [47], solid-phase microextraction (SPME) fibres [43] and filter substrates (mostly quartz fibre filters but also PTFE membranes [1, 42, 48, 49]). When filter substrates are used, atmospheric particles are collected over 24-h periods using high-volume (dichotomous or single-filter instruments [1, 48]), medium-volume or low-volume samplers (operated to ensure collection of sufficient aerosol mass [37, 50]). Samples were always stored at low temperamres (refrigerated or frozen) to ensure sample preservation. 

Liquid chromatography coupled with electrochemical detection this technique, in combination with a high-throughput liquid-absorption pre-concentrator (HTLAP) that sampled air and collected analytes from vapours or aerosols into a small volume of liquid absorbent, was used by Zaromb et al. [47] for the detection and analysis of cocaine and heroin in air. 

Note 1 The liquid absorbed can be water or an organic liquid. 

Indeed, recently SEDDS themselves have been delivered as liquids absorbed onto powders such as colloidal silicon dioxide or microcrystalline cellulose (Nazzal et al., 2002). Selection of the absorbent was obviously critical to the performance of the system but, as an aside, it seems that this approach negates the rapid release properties of a SEDDS. It will be interesting to follow the future of this technology. 

Indeed, it is often impossible to distinguish between an analyte originating from the aerosol and the same analyte originating from the gas phase after incorporation into a liquid absorber the inability to distinguish between particulate NH4+ and NH3 (g) or between particulate N03 and HN03 (g), once collected into an aqueous solution, can be cited as examples. In such cases, diffusion-based collection has proven to be the only approach for reliably measuring a gas in the presence of an aerosol. 

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