Recovery techniques

Two different techniques may be utilized to recover particulate matter filtration or centrifugation. The latter is not widely used and is often reserved for chemical analysis of large volumes of water. Nevertheless, Breck (1978), has demonstrated that the method may produce a 30% better recovery. 

Filtration is most widely employed, but the variety of filter types and porosities used makes any comparison between the results difficult. Three main types are commonly employed membranes made of cellulose esters or polycarbonate, glass fiber filters and silver filters. 

The theoretical limit fixed at 0.45 pm is purely arbitrary, and the previous observations encourage us to use techniques to lower this limit, to allow the recovery of very small particles and colloids. 

The volumes filtered are quite different, ranging from milliliters for microscopic studies to cubic meters for extensive chemical studies (Handa et al., 1970). Recovering sufficient material without undergoing any degradation is one of the main difficulties for precise organic chemistry studies. The utilization of immersed pumps allows the filtration of large volumes of sea water, even when the ship is underway (Krishnaswami and Sarin, 1976). 

In all cases filtration must be performed soon after the sampling procedure in order to avoid any deposition onto the sampler or container surfaces or aggregation of small particles. 

In the furfural distillation, both diacetyl and 2,3-pentanedione end up in the fraction of low boilers, commonly called raw solvent . For diacetyl this is clear as it has a boiling point of 88 C, and for 2,3-pentanedione, having a boiling point of 112 C, this is due to its azeotrope with water which boils below 100 C. 

The fraction of low boilers obtained in the distillation of furfural is a rather complicated mixture typically consisting of the following components, listed in the order of increasing boiling points  

Of these components, only ethanol is not formed in the furfural reactors. In the typical case of bagasse as the raw material, ethanol results from a partial unwanted fermentation of the cane on the fields and in the sugar mill. In other words, the ethanol is already part of the bagasse before the latter enters the furfural reactors. 

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This rather low recovery factor may be boosted by implementing secondary recovery techniques, particularly water Injection, or gas injection, with the aim of maintaining reservoir pressure and prolonging both plateau and decline periods. The decision to implement these techniques (only one of which would be selected) Is both technical and economic. Technical considerations would be the external supply of gas, and the... 

A considerable percentage (40% - 85%) of hydrocarbons are typically not recovered through primary drive mechanisms, or by common supplementary recovery methods such as water flood and gas injection. This is particularly true of oil fields. Part of the oil that remains after primary development is recoverable through enhanced oil recovery (EOR) methods and can potentially slow down the decline period. Unfortunately the cost per barrel of most EOR methods is considerably higher than the cost of conventional recovery techniques, so the application of EOR is generally much more sensitive to oil price. 

Domestic petroleum, natural gas, and natural gas Hquids production has declined at a rate commensurate with the decrease in reserves (see Table 2). Consequently, the reserves/production ratio, expressed in years, remained relatively constant from about 1970 through 1992, at 9—11 years (16). Much of the production in the early 1990s is the result of enhanced oil recovery techniques water flooding, steam flooding, CO2 injection, and natural gas reinjection. 

The butane-containing streams in petroleum refineries come from a variety of different process units consequently, varying amounts of butanes in mixtures containing other light alkanes and alkenes are obtained. The most common recovery techniques for these streams are lean oil absorption and fractionation. A typical scheme involves feeding the light hydrocarbon stream to an absorber-stripper where methane is separated from the other hydrocarbons. The heavier fraction is then debutanized, depropanized, and de-ethanized by distillation to produce C, C, and C2 streams, respectively. Most often the stream contains butylenes and other unsaturates which must be removed by additional separation techniques if pure butanes are desired. 

In the latter twentieth century, spent automotive catalysts have emerged as a significant potential source of secondary Pt, Pd, and Rh. In North America, it has been estimated that 15.5 metric tons per year of PGM from automotive catalysts are available for recycling (22). However, the low PGM loading on such catalysts and the nature of the ceramic monoliths used have required the development of specialized recovery techniques as well as the estabhshment of an infrastmcture of collection centers. These factors have slowed the development of an automotive catalyst recycling iadustry. 

In principle, the nonmining recovery of bitumen from tar sand deposits is an enhanced oil recovery technique and requires the injection of a fluid into the formation through an injection weU. This leads to the in situ displacement of the bitumen from the reservoir and bitumen production at the surface through an egress (production) weU. There are, however, several serious constraints that are particularly important and relate to the bulk properties of the tar sand and the bitumen. In fact, both recovery by fluid injection and the serious constraints on it must be considered in toto in the context of bitumen recovery by nonmining techniques (see PETROLEUM, ENHANCED OIL RECOVERY). 

A. P. Kreuding, "Power Recovery Techniques as AppHed to Fluid Catalytic Cracking Unit Regenerator Flue Gas," presented at 79thFEChE... 

A clear solution of aluminum citrate neutralized to pH 7 is used for in situ gelling of polymers in polymer flooding and well stimulation in enhanced oil recovery techniques (128—132). The citrate chelate maintains aluminum ion solubiUty and controls the rate of release of the aluminum cross-linker. 

The structure/property relationships in materials subjected to shock-wave deformation is physically very difficult to conduct and complex to interpret due to the dynamic nature of the shock process and the very short time of the test. Due to these imposed constraints, most real-time shock-process measurements are limited to studying the interactions of the transmitted waves arrival at the free surface. To augment these in situ wave-profile measurements, shock-recovery techniques were developed in the late 1950s to assess experimentally the residual effects of shock-wave compression on materials. The object of soft-recovery experiments is to examine the terminal structure/property relationships of a material that has been subjected to a known uniaxial shock history, then returned to an ambient pressure... 

Micromechanical theories of deformation must be based on physical evidence of shock-induced deformation mechanisms. One of the chapters in this book deals with the difficult problem of recovering specimens from shocked materials to perform material properties studies. At present, shock-recovery methods provide the only proven teclfniques for post-shock examination of deformation mechanisms. The recovery techniques are yielding important information about microscopic deformations that occur on the short time scales (typically 10 -10 s) of the compression process. 

Absorption is widely used as a raw material and/or product recovery technique in separation and purification of gaseous streams containing high concentrations of VOC, especially water-soluble compounds such as methanol, ethanol, isopropanol, butanol, acetone, and formaldehyde. Hydrophobic VOC can be absorbed using an amphiphilic block copolymer dissolved in water. However, as an emission control... 

H longitudinal relaxation time, measured by the inversion-recovery technique, at 293 K. 

Adsorption is the most widely used solvent-recovery technique and is also used for odor control. The latter application is necessary to meet statutory air pollution control requirements. Depending on the application, adsorption can be used alone or with other techniques such as incineration. " ... 

Proved developed oil and gas reseives are reseives that can be expected to be recovered through existing wells with existing equipment and operating methods. Additional oil and gas expected to be obtained through the application of fluid injection or other improved recovery techniques for supplementing the natural forces and inechanisnis of primary recovery... 

The NaCl-KCl eutectic is used when the pregnant extraction salt is to be processed by aqueous recovery (this is the salt currently used at Rocky Flats because calcium follows americium in the present aqueous recovery process). The NaCl-CaCl system is used when the salt is processed by pyrochemical means to recover the americium and residual plutonium. When the pyrochemical recovery technique is used, the NaCl-CaCl2-MgCl2 salt is contacted with liquid calcium metal at approximately 850°C in a batch extractor. The calcium reduces A111CI3,... 

Selective, spin-lattice relaxation-rates are measured by the inversion-recovery technique. A rather weak, 180° pulse of very long duration (10-50 ms) inverts a multiplet (single-selective) or two multiplets (double-selective) in the spectrum of asperlin (1 see Fig. 2 ) and the recovery of the... 

A. H. Al-Khafaji. Implementations of enhanced oil recovery techniques in the Arab world are questioned. In Proceedings Volume,... 

Event though there is a considerable overlap of the pyrometallurgical and the hydro-metallurgical routes adopted, the industrial recovery techniques are generally based on pyrometallurgical extraction. 

Some processes, such as air separation, depend on efficient energy recovery for economic operation, and in all processes the efficient utilisation of energy recovery techniques will reduce product cost. 

A widely used metal salt recovery technique is evaporation. With evaporation, plating chemicals are concentrated by evaporating water from the solution. Evaporators may use heat or natural evaporation to remove water.22 28 Additionally, evaporators may operate at atmospheric pressure or under vacuum. 

Electrolytic recovery (ER) is the oldest metal recovery technique. Metal ions are plated-out of solution electrochemically by reduction at the cathode.34 There are essentially two types of cathodes used for this purpose a conventional metal cathode and a high surface area cathode (HSAC). Both cathodes can effectively plate-out metals, such as gold, zinc, cadmium, copper, and nickel.22... 

This section describes the treatment technologies currently in use to recover or remove wastewater pollutants normally found at coil coating facilities. The treatment processes can be divided into six categories recovery techniques, oil removal, dissolved inorganics removal, cyanide destruction, trace organics removal, and solids removal.5-14 Adoption of specific treatment processes will depend on the following ... 

Recovery of process chemicals in coil coating plants is applicable to chromating baths and sealing rinses. Recovery techniques currently in use include ion exchange and electrochemical chromium regeneration.8-9... 

Recovery techniques are treatment methods used for the purpose of recovering or regenerating process constituents, which would otherwise be discarded. Included in this group are5-7... 

Precious metal wastes can be treated using the same treatment alternatives as those described for treatment of common metal wastes. However, due to the intrinsic value of precious metals, every effort should be made to recover them. The treatment alternatives recommended for precious metal wastes are the recovery techniques—evaporation, ion exchange, and electrolytic recovery. 

One obvious question is why return to lime as a treatment reagent, given that caustic results in a smaller residue volume and a waste that can undergo reclamation The answer lies in the three points that result from the implementation of the HSWA hierarchy. As source reduction and material reuse and recovery techniques are applied, facilities will be generating... 

Other enhanced DNAPL recovery techniques have been implemented utilizing both water flooding and well bore vacuum. Essentially, this minimizes drawdown, allowing a maximum pumping rate of the DNAPL/water mixture. 

Recovery Techniques to Petroleum Production in the United States, U.S. Dept, of Energy, DOE/BETC/RI-83/9 (DEB4003910), Jan., 1984. 

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