Recovery from solids

In addition to separation from gases and other liquids, solvents are often recovered from solids or residues. This typically follows from the presence of a solid impurity, or the use of a solid drying agent, but may also follow a crystallisation process. Alternatively prior to disposal of the solid, wherein the presence of a solvent would be hazardous, wasteful or environmentally unacceptable. A number of techniques are applicable. 

Typical materials include woven fibres, metal screens or fabrics, pressed felt or cotton batting, sheets of synthetic polymers, paper, sand, coal, silica porcelain and many more. Filtration equipment is equally diverse for both batch and continuous processing [23]. 

Cross-flow filtration, in which the slurry of solid and liquid is applied tangentially to the filter bed, offers significant advantages over conventional filtration. These can be summarised as  

The increase in filtration rate allows the use of microporous or ultrafiltration membranes for retention of micrometre sized particulates thus increasing the degree of separation of solid and liquid. 

This highlights the emergence of the use of membranes in either reverse osmosis or ultrafiltration systems 

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In the absence of any added salts, the APCI-MS spectra were dominated by the Na+ adducts, as shown in Fig. 2.8.5. The NH4 and K+ adducts were present at lower intensities, the latter especially for the higher molecular weight analogues. Addition of CH3CO2NH4 did not simplify the adduct formation to [M + NH4]+ species as observed in ESI-MS and the best results for APCI-MS analysis were obtained without addition of any salt solutions. Application of this method to determinations of M2D-C3-0-(E0)n-Me recovery from solid substrates was achieved, using triethylene glycol monohexyl ether [C6(EO)3] as the internal standard (Fig. 2.8.5) [29],... 

Smith, D. L. Clemmer, R. G. Jankus, V. Z. Rest, J. "Analysis of In Situ Tritium Recovery From Solid Fusion-Reactor Blankets" Proc. 4th ANS Top. Mtg. Tech. Controlled Nucl. Fusion King of Prussia, PA, 1980. 

Fig. 1. Scheme of molybdenum recovery from solid industrial wastes. 

An Evaluation of Modular Incinerators for Energy Recovery from Solid Wastes... 

Resource Recovery Process System Developed by National Project. Phase I of the national project was carried out from 1973 to 1976 for developing the feasible technology and systems of resource recovery from solid wastes, and the demonstration plant (100 tons/day) for the material - reclamation system in phase II is under construction. The pyrolysis processes which have been developed in phase I of the national project are as follows ... 

Recovery from solids Sedimentation Batch or continuous Centrifugal process may be preferred Decanting may be required Low solids content... 

Boumehdi, P., Guigon, P., and Large, J.F., Heat recovery from solids in a raining bed exchanger. Heat Recovery SysL, 5, 407-414, 1985. 

L. Dia2 and co-workers. Resource Recovery From Munidpal Solid Waste, Vols. I and II, CRC Press, Boca Raton, Fla., 1982. f. Holmes, Refuse Reycling and Recovey, ]o m Wiley Sons, Inc., New York, 1981. 

Processing and Recovery The functional element of processing and recoveiy includes all the techniques, equipment, and facilities used both to improve the efficiency of the other functional elements and to recover usable materials, conversion products, or energy from solid wastes. Materials that can be recycled are exported to facilities equipped to do so. Residues go to disposal. 

The purpose of this subsection is to introduce the reader to the tech-niqiies and methods used to recover materials, conversion products, and energy from solid wastes. Topics to be considered include (I) processing techniques for solid waste, (2) processing techniques for hazardous wastes, (3) materials-recoveiy systems, (4) recovery of biological conversion products, (5) therm processes, and (6) waste-to-energy systems. 

Recovery of Riologieal Conversion Products Biological conversion produces that can be derived from solid wastes include compost, methane, various proteins and alcohols, and a variety of other intermediate organic compounds. The principal processes that have been used are reported in Table 25-64. Composting and anaerobic digestion, the two most highly developed processes, are considered further. The recovery of gas from landfills is discussed in the portion of this sec tion dealing with ultimate disposal. 

TABLE 25-64 Biological and Thermal Processes Used for Recovery of Conversion Products from Solid Waste... 

TABLE 25-67 Typical Thermal Efficiency and Plant Use and Loss Factors for Individual Components and Processes Used for Recovery of Energy from Solid Wastes... 

FIG. 25-74 Use of an impermeable liner to control the movement of gases and leachate in landfills, (a) Without gas recovery, (h) With gas recovery. (From G, Tchohanoglous, H. Theisen, and R. Eliassen, Solid Wastes Engineering Principles and Management Issues, McGraw-Hill, New York, 1977.)... 

MIXED COMBUSTION OF AUTOMOTIVE SHREDDER RESIDUES WITH MUNICIPAL SOLID WASTE A SOUND ROUTE TO ENERGY RECOVERY FROM END OF LIFE VEHICLES... 

According to APME, energy recovery should be the preferred waste disposal route for polymeric materials that are very contaminated, bonded, laminated to other materials, or are at the end of their performance with respect to their physical/chemical properties. This paper takes a detailed look at energy recovery from municipal solid waste combustors, and considers the effect of polymeric materials. 

The use of ethyl acetate was suggested by Oszmianski and Lee (1990) to wash out phenolics other than anthocyanins. Finally, a relatively pure anthocyanin extract can be removed from the colnmn with acidified methanol (0.1% HCl). Anthocyanin extracts can be enriched in this way by use of solid phase purification, which is especially helpful for diluted samples such as biological samples. Two factors in the nse of these purification techniques are the stability of anthocyanins to the conditions nsed and the ease of anthocyanin recovery from the column. ... 

In the case when one of the two measurements of the contingency table is divided in ordered categories, one can construct a so-called thermometer plot. On this plot we represent the ordered measurement along the horizontal axis and the scores of the dominant latent vectors along the vertical axis. The solid line in Fig. 32.9 displays the prominent features of the first latent vector which, in the context of our illustration, is called the women/men factor. It clearly indicates a sustained progress of the share of women doctorates from 1966 onwards. The dashed line corresponds with the second latent vector which can be labelled as the chemistry/ other fields factor. This line shows initially a decline of the share of chemistry and a slow but steady recovery from 1973 onwards. The successive decline and rise are responsible for the horseshoe-like appearance of the pattern of points representing... 

Supercritical fluid extraction (SFE) is generally used for the extraction of selected analytes from solid sample matrices, but applications have been reported for aqueous samples. In one study, recoveries of 87-100% were obtained for simazine, propazine, and trietazine at the 0.05 ug mL concentration level using methanol-modified CO2 (10%, v/v) to extract the analytes, previously preconcentrated on a C-18 Empore extraction disk. The analysis was performed using LC/UV detection. Freeze-dried water samples were subjected to SFE for atrazine and simazine, and the optimum recoveries were obtained using the mildest conditions studied (50 °C, 20 MPa, and 30 mL of CO2). In some cases when using LEE and LC analysis, co-extracted humic substances created interference for the more polar metabolites when compared with SFE for the preparation of the same water sample. ... 

Principles and Characteristics Supercritical fluid extraction uses the principles of traditional LSE. Recently SFE has become a much studied means of analytical sample preparation, particularly for the removal of analytes of interest from solid matrices prior to chromatography. SFE has also been evaluated for its potential for extraction of in-polymer additives. In SFE three interrelated factors, solubility, diffusion and matrix, influence recovery. For successful extraction, the solute must be sufficiently soluble in the SCF. The timescale for diffusion/transport depends on the shape and dimensions of the matrix particles. Mass transfer from the polymer surface to the SCF extractant is very fast because of the high diffusivity in SCFs and the layer of stagnant SCF around the solid particles is very thin. Therefore, the rate-limiting step in SFE is either... 

Crystallisation is used for the production, purification and recovery of solids. Crystalline products have an attractive appearance, are free flowing, and easily handled and packaged. The process is used in a wide range of industries from the small-scale production of specialised chemicals, such as pharmaceutical products, to the tonnage production of products such as sugar, common salt and fertilisers. 

Giang NTH (2011) Potentials and limitations of energy recovery from municipal solid waste (MSW) in Vietnam. PhD Thesis, Institute of Waste Management and Contaminated Site Treatment, University of Technology, Dresden... 

Longitudinal relaxation (T ) Recovery of magnetisation along the z axis. The energy lost manifests itself as an infinitesimal rise in temperature of the solution. This used to be called spin-lattice relaxation, a term which originated from solid-state NMR. 

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