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Recycle response

Economic Aspects. The 1992 MEK nameplate capacity for the United States, East Asia, and Western Europe is Hsted in Table 5. During the period 1980—1989 MEK achieved a negative growth rate as demand dropped from 311,000 (48) to 228, 000 t/yr (49). Stricter VOC regulations were largely responsible for the decline, and the trend will continue as solvent recovery and recycling, as well as substitution away from MEK, take effect. [Pg.489]

Electrolytic Preparation of Chlorine and Caustic Soda. The preparation of chlorine [7782-50-5] and caustic soda [1310-73-2] is an important use for mercury metal. Since 1989, chlor—alkali production has been responsible for the largest use for mercury in the United States. In this process, mercury is used as a flowing cathode in an electrolytic cell into which a sodium chloride [7647-14-5] solution (brine) is introduced. This brine is then subjected to an electric current, and the aqueous solution of sodium chloride flows between the anode and the mercury, releasing chlorine gas at the anode. The sodium ions form an amalgam with the mercury cathode. Water is added to the amalgam to remove the sodium [7440-23-5] forming hydrogen [1333-74-0] and sodium hydroxide and relatively pure mercury metal, which is recycled into the cell (see Alkali and chlorine products). [Pg.109]

The reaction is mn for several hours at temperatures typically below 100°C under a pressure of carbon monoxide to minimise formamide decomposition (73). Conversions of a-hydroxyisobutyramide are near 65% with selectivities to methyl a-hydroxyisobutyrate and formamide in excess of 99%. It is this step that is responsible for the elimination of the acid sludge stream characteristic of the conventional H2SO4—ACH processes. Because methyl formate, and not methanol, is used as the methylating agent, formamide is the co-product instead of ammonium sulfate. Formamide can be dehydrated to recover HCN for recycle to ACH generation. [Pg.252]

In fact, recycling was a valuable U.S. industry for decades (witness the success of industrial recycling), especially in metals, newsprint, and some types of glass and aluminum cans. Only when regulators, in response to pubHc pressure, attempted to mandate the collection of materials that were in many instances expensive to collect and process did recycling begin to encounter problems. [Pg.547]

Multienzyme electrodes can increase sensitivity from micromolar to nanomolar detection levels (53,57). In this case the substrate is converted to a detectable product by one enzyme, then that product is recycled into the initial substrate by another enzyme resulting in an amplification of the response signal. For example, using lactate oxidase and lactate dehydrogenase immobilized in poly(vinyl chloride), an amplification of 250 was obtained for the detection oflactate (61). [Pg.103]

Solvent Recovery. Most of the activated carbon used in gas-phase applications is employed to prevent the release of volatile organic compounds into the atmosphere. Much of this use has been in response to environmental regulations, but recovery and recycling of solvents from a range of industrial processes such as printing, coating, and extmsion of fibers also provides substantial economic benefits. [Pg.535]

Exxon was the first to investigate the suitabiUty of a wide range of different U.S. coals for conversion. Operation of the EDS process was demonstrated in a 230 t/d unit in Baytown, Texas that had a start-up in May of 1980. Data on the response of a variety of coals to once-through and bottoms recycle operations are shown in Eigure 4. Eigure 5 presents typical Hquefaction product distributions for the system operated both with and without the Elexicoking (fluidized-bed coking) option. [Pg.283]

Time-Delay Compensation Time delays are a common occurrence in the process industries because of the presence of recycle loops, fluid-flow distance lags, and dead time in composition measurements resulting from use of chromatographic analysis. The presence of a time delay in a process severely hmits the performance of a conventional PID control system, reducing the stability margin of the closed-loop control system. Consequently, the controller gain must be reduced below that which could be used for a process without delay. Thus, the response of the closed-loop system will be sluggish compared to that of the system with no time delay. [Pg.733]

Intuition dictates that reducing nutrient inputs, particularly phosphorus, must reduce the supportable biomass. Relationships show that sustained response cannot be effected before it can be demonstrated (i) that nutrient is exhausted at a lower concentration of algae than the existing maxima and (ii) that in situ recycling is unable to make up the shortfall. [Pg.36]

A good review of the transient response method in heterogeneous catalysis was published by Kobayashi and Kobayashi (1974). These authors credit Bermett (1967) for applying this previously microcatalytic research technique to recycle reactors and thereby, in view of this author, to engineering problems. [Pg.151]

In keeping with its commitment to economically and environmentally responsible recycling, the American Plastics Council (APC) has a Web site feature that connects buyers and sellers of recycled plastics. The site, located at www.plasticsresource. com/recyding/marketsdb/index.phtinl allows users to select the type of plastic they want and a source location from which to obtain it. [Pg.373]

The human genome contains more than 90 different DUBs. Besides cleaving ubiquitin from distinct substrates, DUBs are also responsible for the recycling of free ubiquitin from ubiquitin chains and processing of ubiquitin- or ubiquitin like precursor proteins. Certain DUBs are also associated with the proteasome in order to detach ubiquitin chains before proteolysis. [Pg.422]

Regulation of NHE3 involves many hormonal and physical mechanisms. Acutely, NHE3 activity is promoted by an increase in intracellular pH and this response is rapid. Furthermore, the increase in activity is proportional to the duration of acidification. Chronic acidification promotes recycling of NHE3 from subapi-cal endosomes to the plasma membrane. [Pg.811]

Noradrenaline transporters (NAT) are localized in the presynaptic plasma membrane of adrenergic nerve terminals. They belong to a family of proteins with 12 putative transmembrane proteins which are responsible for recycling of released neurotransmitters (noradrena-line/adrenaline, dopamine, serotonin, amino acid transmitters) back into the presynaptic nerve ending. Noradrenaline transporters can be blocked by a number of different antidepressant drags, including tricyclic antidepressants (e.g. desipramine) and selective noradrenaline reuptake inhibitors (e.g. reboxetine). [Pg.883]

Chitinases are responsible for the breakdo vn and recycling of chitin. With several gigatons of chitin being produced annually, it is the second most abundant polymer... [Pg.76]

Besides nitrogen fixation, the only other major source of reduced nitrogen is the decomposition of soil or aquatic organic matter. This process is called ammonification. Heterotrophic bacteria are principally responsible for this. These organisms utilize organic compounds from dead plant or animal matter as a carbon source, and leave behind NH3 and NHJ, which can then be recycled by the biosphere. In some instances heterotrophic bacteria may incorporate a complete organic molecule into their own biomass. The majority of the NH3 produced in this way stays within the biosphere however, a small portion of it will be volatilized. In addition to this source, the breakdown of animal excreta also contributes to atmospheric... [Pg.327]


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See also in sourсe #XX -- [ Pg.396 ]




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