Monitors methane

Conversion of tlie carbon oxides to methane, at the expense of hydrogen, goes almost to completion and the CO and CO2 content of the treated gas is on the order of a few ppm. A methanator typically operates in the temperature range of 300—400°C. These reactions are strongly exothermic and hence the CO and CO2 at the inlet to the methanator should be carefully monitored, to avoid temperature mnaway. 

The large number of individual hydrocarbons in the atmosphere and the many different hydrocarbon classes make ambient air monitoring a very difficult task. The ambient atmosphere contains an ubiquitous concentration of methane (CH4) at approximately 1.6 ppm worldwide (9). The concentration of all other hydrocarbons in ambient air can range from 100 times less to 10 times greater than the methane concentration for a rural versus an urban location. The terminology of the concentration of hydrocarbon compounds is potentially confusing. Hydrocarbon concentrations are referred to by two units—parts per million by volume (ppmV) and parts per million by carbon (ppmC). Thus, 1 fx of gas in 1 liter of air is 1 ppmV, so the following is true ... 

To handle the methane gas generated from the 42.5-acre site, an active interior gas collection system was installed as shown in Figure 11. The installation consisted of 42 recovery wells, a gas collection header system, condensate traps, blower station and a flare station. In addition, a methane monitoring system consisting of thirty-two 2-inch wells was installed around the site (U.S. EPA, 1987). 

Fig. 18-14 Ice-core methane record for the past 1000 years. Plus signs are data from Eurocore in central Greenland (Blunier et ah, 1993), and open circles are data from DE08, an ice core in East Antarctica (Etheridge et ah, 1992). Dots are monthly atmospheric data from the South Pole (NOAA Climate Monitoring and Diagnostics Laboratory in Boulder, Colorado).

Kinsman, R., Sauer, F. D., Jackson, H. A., and Wolynetz, M. S. (1995). Methane and carbon dioxide emissions from dairy cows in full lactation monitored over a six-month period. 

A mechanistic model for the kinetics of gas hydrate formation was proposed by Englezos et al. (1987). The model contains one adjustable parameter for each gas hydrate forming substance. The parameters for methane and ethane were determined from experimental data in a semi-batch agitated gas-liquid vessel. During a typical experiment in such a vessel one monitors the rate of methane or ethane gas consumption, the temperature and the pressure. Gas hydrate formation is a crystallization process but the fact that it occurs from a gas-liquid system under pressure makes it difficult to measure and monitor in situ the particle size and particle size distribution as well as the concentration of the methane or ethane in the water phase. 

Pt/H-MCM-22 catalysts for methane combustion have been prepared by ion-exchange of a highly crystalline H-MCM-22 zeolite using [Pt(NH3)4](N03)2. The activation procedure of the catalyst precursor has been optimized and all steps monitored by HRTEM, SEM and FTIR of CO adsorbed. The preliminary decomposition/calcination of the ion exchanged sample is very crucial in that influence the final properties of platinum active species. 

Unlike methane and the other alkanes, aromatic hydrocarbons have absorptions in the UV part of the spectrum, and thus may be detected through UV spectrometry using silica fibers. This scheme is useful for "aromatic" water pollutants such as toluenes and xylenes with their absorption bands between 250 and 300 nm. Similarly, nitrate anion can be monitored (albeit with low sensitivity) in water via its UV absorption at 250 nm. 

Chan K., Ito H., Inaba H., Optical remote monitoring of methane gas using low-loss optical fiber link and indium gallium arsenide phosphide light-emitting diode in 1.33-mm region, Appl. Phys. Lett. 1983 43 634. 

The chemiluminescent reaction with chlorine dioxide provides a highly sensitive and highly selective method for only two sulfur compounds, hydrogen sulfide and methane thiol [81]. As in the flame photometric detector (FPD), discussed below, atomic sulfur emission, S2(B3S -> ) is monitored in the wave-... 

Recently, such a temperature oscillation was also observed by Zhang et al (27,28) with nickel foils. Furthermore, Basile et al (29) used IR thermography to monitor the surface temperature of the nickel foil during the methane partial oxidation reaction by following its changes with the residence time and reactant concentration. Their results demonstrate that the surface temperature profile was strongly dependent on the catalyst composition and the tendency of nickel to be oxidized. Simulations of the kinetics (30) indicated that the effective thermal conductivity of the catalyst bed influences the hot-spot temperature. 

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