Recovery processes thermal

Thermal desorption treatment is generally considered to be an alternative to incineration. Thermal desorption operates at much lower temperatures than incineration and keeps the heating systems independent of the wastes, which minimizes off-gas production. The technology can be used as a waste minimization process, isolating and concentrating waste constituents, or as a product recovery process. Thermal desorption can also be used to separate contaminants in mixed waste streams by removing volatile constituents. 

Some alkylphenols in commercial production have low vapor pressures and/or low thermal decomposition temperatures. Eor these products, the economics of distillation are poor and other recovery processes are used. Crystallisation from a solvent is the most common nondistUlation method for the purification of these alkylphenols. 

At a given NaCI concentration, an increase in temperature resulted in an increase in interfacial tension. In contrast, for a narrow range of CaCI concentrations, interfacial tensions decreased with increasing temperatures. Changes of the amphiphile at the oil/water interface accounted for some of the experimental observations. Since the extent of oil desaturation is dependent on interfacial tension, the tension data could be used to assess the ability of surfactants to reduce oil saturations in the reservoir for application of surfactants and foams to thermal recovery processes. 

Currently, there are three possible gas recovery processes for hydrates (1) thermal stimulation, (2) depressurization and (3) inhibitor injection. Very limited thermal stimulation and depressurization tests were reported for the Mallik natural gas hydrate reservoirs, together with numerical simulations (Moridis et al. 2004,... 

Of the above-mentioned challenges of oil-sands production, the heavy dependence on natural gas is among the most critical. Table 3.5 shows the specific natural gas demand per barrel of bitumen for mining and extraction, (thermal) in-situ recovery and upgrading operations, as well as for the production of hydrogen. Depending on the recovery process, up to 25% of the energy content of the SCO is used in the form of natural gas. 

This reaction is thermally neutral. The heat absorbed in the CH4 reforming reaction is released by the subsequent reaction of the H2 product at the anode of the fuel cell. If, therefore, the reforming process can be carried out in close proximity to and in thermal contact with the anode process, the thermal neutrality of the overall CH4 oxidation process can be approximated. And the heat removal and recovery process for the fuel cell system can deal merely with the heat produced by its operational irreversibilities. 

The most important relaxation processes in NMR involve interactions with other nuclear spins that are in the state of random thermal motion. This is called spin-lattice relaxation and results in a simple exponential recovery process after the spins are disturbed in an NMR experiment. The exponential recovery is characterised by a time constant Tj that can be measured for different types of nuclei. For organic liquids and samples in solution, Tj is typically of the order of several seconds. In the presence of paramagnetic impurities or in very viscous solvents, relaxation of the spins can be very efficient and NMR spectra obtained become broad. 

The steam-enhanced recovery process (SERF) is an in situ technology designed to remove and treat volatile and semivolatile organic compounds (VOCs and SVOCs) in contaminated soils by using steam injection and vacuum extraction. The technology is based on the idea that added heat (thermal enhancement) increases the volatility and mobility of SVOCs and VOCs and thus facilitates the extraction of soil contaminants. The process works by injecting high-quality steam... 

Mercury Recovery Services, Inc. (MRS), has developed the Mercury Removal/Recovery Process (MRRP) to treat media contaminated with mercury. The ex situ process uses medium-temperature thermal desorption to remove the mercury from contaminated wastes. Process wastes are heated in a two-step process to recover metallic mercury in a 99% pure form. MRS claims MRRP can be applied to soils, activated carbon, mixed waste, catalysts, electrical equipment, batteries, lamps, fluorescent bulbs, mercurous and mercuric compounds, mercury-contaminated waste liquids, and debris. 

Annealing in metals can first lead to stress relaxation in which stored internal strain energy due to plastic deformation is relieved by thermally activated dislocation motion (see Figure 5.18). Because there is enhanced atomic mobility at elevated temperatures, dislocation density can decrease during the recovery process. At still higher temperatures, a process known as recrystallization is possible, in which a new set of... 

At elevated temperatures, the thermal recovery processes described in Section 5.1.2.3 can occur concurrently with deformation, and both strength and strain hardening are consequently reduced. The latter effect results in decreasing the difference between yield and tensile strengths until at sufficiently high temperatures, they are essentially equal. At lower temperatures, temperature has a marked influence on deformation in crystalline materials. Temperature can affect the number of active slip systems in some... 

Foams, in the form of froths, are intimately involved and critical to the success of many mineral-separation processes (Chapter 10). Foams may also be applied or encountered at all stages in the petroleum recovery and processing industry (oil-well drilling, reservoir injection, oil-well production and process-plant foams). A class of enhanced oil recovery process involves injecting a gas in the form of a foam. Suitable foams can be formulated for injection with air/nitrogen, natural gas, carbon dioxide, or steam [3,5]. In a thermal process, when a steam foam contacts residual crude oil, there is a tendency to condense and create W/O emulsions. Or, in a non-thermal process, the foam may emulsify the oil itself (now as an O/W emulsion) which is then drawn up into the foam structure the oil droplets eventually penetrate the lamella surfaces, destroying the foam [3], See Chapter 11. 

The selective treatments of flame-retardant plastics are fulfilled when the WEEE plastics are treated (recovered, recycled, thermally disposed) together with other wastes, as is the case with energy recovery processes that are currently practiced in Europe.78 79 In this scenario, the joint recovery of plastics containing brominated flame-retardants with other materials complies with the purpose of the WEEE Directive without the removal requirement of Annex II. Recent technical studies and legal reviews demonstrate that WEEE plastics containing brominated flame-retardants are compatible with the EU WEEE Directive without separation and removal prior to the waste treatment. This has been confirmed by the 2006 EU Member States guidance on the separation requirements of the WEEE Directive.80... 

Figure 23 demonstrates that aging kinetics slow down as the temperature increment (T — Ta) increases, i.e., the recovery process is a thermally stimulated phenomenon which requires segmental mobility of the polymer in its glassy state. 

As the PSA process is operated at lower temperature, without heating in regeneration, it was thought not to be advantageous as for solvent recovery. As a result, it was not fiilly studied yet, compared with the recovery by thermal regeneration. 

Meldrum et al. (1999) recently derived an expression to describe the relationship between amorphization dose and temperature based on a composite model involving both direct impact and close-pair recombination processes. This model provides more realistic values for the activation energies of thermal recovery processes, but the curves generated from the expression predict a sharp curvature near Tc. 

The two main thermal recovery processes are steam injection and in situ combustion. In the steam injection process, steam of 80% quality is injected into the reservoir to displace oil. The steam can be injected continuously (called steam drive ) or intermittently (called cyclic steam injection ). In the steam drive process, steam is injected in several injection wells and the oil is produced in several production well. In cyclic injection process, steam is injected in several (previously producing) wells for 2-6 weeks, soaked for 3-7 days, and produced back for a few weeks or months. This cycle can be repeated several times. Often, the steam flood is preceded by cyclic injection. Steam injection has been used commercially for several decades. In fire flooding or in situ combustion process, air is injected and ignited inside the reservoir. A combustion front... 

In all thermal recovery processes, tar sand is subjected to high processing temperatures, about 450-550°C for pyrolysis, and the residual coked sand is further heated to about 550-650°C during the combustion step. At these conditions, an acceptable thermal efficiency can only be obtained if a significant portion of the sensible heat in the spent sand is recovered and introduced back into the process. Almost all the processes in Table I provide for heat recovery from spent sand before it is discarded. 

Since 1995, consumer and industrial Ni/Cd battery recycling in the U.S. has been primarily done at the International Metals Reclamation Company, Inc. (INMETCO) using a process licensed from SAFT NIFE. The cadmium is distilled from the plates using a low temperature thermal process, and the material is used for new battery production. The nickel content of the battery goes into the standard INMETCO stainless steel remelt alloy production. In general, this thermal recovery process makes up the majority of the world recycling capacity. The cadmium is recovered and purified as the metal or can be converted to cadmium oxide. 

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