Gas collectors

Gas collectors A sampling bag used to collect a sample for analysis. 

This section presents an overview of collector design and materials, followed by a discussion of the three parts of a liquid management system the LCRS above the primary liner, the secondary leak detection, collection, and removal (LDCR) system between the primary and secondary liners, and the surface water collection system above the closure of the completed facility. The section concludes with a discussion of gas-collector and removal systems. 

In gas-collector systems, either a granular soil layer or a needle-punched nonwoven geotextile is placed directly beneath the LML or clay of a composite cap system. Gas compatibility and air transmissivity are the design factors that must be considered. Methane, the most predominant gas, should be compatible with most types of geotextiles including PET, PP, and PE. 

Gas generation occurs over a period of 70-90 years, so gas-collector and removal systems must work for at least that long to avoid gas pressure on the underside of the cover. 

FIGURE 26.30 Miscellaneous details of a gas-collector system. (Adapted from U.S. EPA, Requirements for Hazardous Waste Landfill Design, Construction, and Closure, EPA/625/4-89/022, U.S. Environmental Protection Agency, Cincinnati, OH, August 1989.)... 

Gas-collector systems are installed directly beneath the low-permeability clay cap in a hazardous waste landfill. Landfills dedicated to receiving only hazardous wastes are relatively new and gas has never been detected in these systems. It may take 40 years or more for gas to develop in a closed secure hazardous waste landfill facility. Because the long-term effects of gas generation are not known, and costs are minimal, U.S. EPA strongly recommends the use of gas-collector systems. 

Figure 26.32 illustrates two moisture control options in gas-collector systems. Gas-collector systems will tolerate a large amount of moisture before air transmissivity is affected. Condensates from the gas-collector layer that form beneath the clay and FMC can also be taken back into the waste, since most hazardous wastes are deposited very dry. 

In these structures the Pontian basal conglomerates are regarded to constitute gas collectors, which were opened within 1182-1273 meters. Their lid is made of from Pliocene and limestone sand Quaternary system gasproof rocks. 

Fig. 15.25. Schematic for a laboratory-scale packed-bed electrode, a, Bed of particles b, current collector c, Luggin capillary d, thermometer e, purging gas in f, gas out g, bubbler h, gas collector i, Luggin capillary j, reference electrode k, Nation film I, counter-electrode m, septum for gas analysis and n, solution flow-in or flow-out. (Reprinted from J, O M. Bockris and J. Kim, J. Appl. Electrochem. 27 625, copyright 1997.)...

At the end of the run, the product was discharged under N2 flow into a metal bomb which was kept at -73 °C. The product was warmed to room temperature and transferred to the atmospheric pressure weathering system which consisted of two BF3-scrubbers, a solenoid valve and a ten-liter gas collector which was equipped with an automatic pressure controller. Both the weathered liquid and the weathered gas were analyzed on a Scot Pak column. 

In general, and as illustrated for the 1977 study of 100°C fumarole at Kilauea, essentially all of the mercury and the other metals are trapped in the 0° condensate (Table 5). Thus, fumarolic gas collectors for metal studies can be simplified. The observed Hg/S weight ratio in the Kilauea condensate was 0.9 X 10 . The Hg/S ratios from the other investigations are summarized in Table 4. Values range from 0.7 to 14 X 10 with a suggestion that Hg/S may increase as the S/Cl decreases. Dedeurwaerder et al. (1982) were part... 

Figure 14.7. Diagram of an anaerobic digestion apparatus of high solid content according to the norm ISO/DIS 15985 (the gas collector must contain water of pH < 2 to prevent the emitted CO2 from dissolving, the volume of (CH4 + COf) is measured in (4), converted into normal conditions by PV/T = PjVi/T1, then expressed in moles using the relation n = pV/RT before being converted into mg ofC by being multiplied by 12,011).

A combination of GC/MS with thermogravimetric analysis simplifies analysis because the sample is ran directly from TGA which does not require sample preparation. TGA is interfaced with GC/MS through evolved gas collector which contains primary and secondary desorption elements which supply GC with samples. ... 

Gas Collection There are both absorbing and adsorbing gas collectors. There are also condensing systems. If the gases and vapors have economic value, collecting or condensing them may be desirable. The efficiency of gas collection varies somewhat with the concentration of gas or vapor in the air. 

A packed-bed microreactor system built from borosilicate glass consisting of an evaporator, aheater, reactor bed and a gas collector was reported by Giorecki et al. [35]. Methanol fuel was used and reformed with a commercial Cu/ZnO catalyst provided by Siid-Chemie. 

Because silica is volatile (Si(0H)4 from Reaction R42 in Table 4.1) at high temperatures in high-pressure steam, it is now excluded from catalysts for steam reforming [85] [389], unless it is combined with alkali. For the same reason, silica-free materials are applied for the brick-lined exit gas collector and in autothermal reformers. Silica would be slowly removed from the catalyst (or brickwork) and deposited in boilers, heat exchangers and catalytic reactors downstream of the reformer. 

Gas Collector— i uncondensed gas is to be measured, a gas meter can be connected to the outlet of the cold trap but with a calcium chloride drying tube between them to keep moisture from collecting in the traps. When analysis of the gas sample is required, the gas can be collected in an empty plastic balloon of suitable size either in place of the meter or following it. The volume of its contents can be determined by calculation from the rise in pressure after expanding the sample into an evacuated vessel of known volume. 

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