Thermal conditioning, pressure filters

A thermal plasma system has been developed for the decomposition of methane. A schematic diagram of the experimental apparatus is shown in Fig. 1. The system consists primarily of D.C. plasma torch, plasma reactor and filter assembly. Plasma was discharged between a tungsten cathode and a copper anode using N2 gas. All the experiments were carried out at atmospheric pressure at 6 kW input electric power and N2 flow rate of 10 to 12 1/min. The feed gas (CH4) flow rates were varied from 3 to 15 1/min depending on the operating conditions, shown in Table. 1. 

Aqueous solutions of ammonium sulfate and ammonium bisulfate were deposited on Fluoropore filters, placed in the direct insertion probe, and analyzed in the chemical ionization mode (H2O reagent) gas. The samples were heated from 100°C to 330 C at 15 C/minute. No sample ions were observed under these anlaysis conditions, even when several micrograms of ammonium salts were analyzed. The thermal decomposition of ammonium salts of sulfate has been the subject of many studies. (29,30) Some pathways include sulfuric acid production at one stage of the decomposition while others suggest ammonia, SO2 and SO3 are the products. None of these accurately simulate the conditions (temperature, pressure, gas flow) present in our chemical ionization source. However, no sulfuric acid ions (H3SO4+, etc.) were ob-served... 

For the photochemical isomerization, a 150 W Xe-lamp or a 200 W Super Pressure Mercury Lamp were used. The light was filtered either by using a monochromator or an interference filter with transmission in the wavelength range of the maximum absorption band of the trans isomer. The other conditions were the same as previously described ( 3). The proceeding of the photochemical and the thermal cis-trans isomerization was followed by measuring the change in the absorption of the trans-isomer in the area of 370-400 nm. 

Diazencs with a variety of substituents have been investigated for the synthesis of either linearly fused or bridged cycloadducts (Table 2). Typical experimental conditions are either refluxing the diazene in a solvent (acetonitrile, THF, or methanol) or irradiation with UV light (high-pressure mercury arc lamp and Pyrex filter). Determination of the activation parameters revealed that the thermal, as well as the photochemical, deazetation proceed via a common 1,3-diyl intermediate27. 

The performance of SCR integrated filters is characterized by the deNOx performance, analogous to catalysts based on flow-through substrates, combined with the additional requirements for the filter component, such as pressure drop, filtration, and thermal robusmess under regeneration conditions. In addition, we have to consider the presence of soot and ash within the component and their influence on all the performance aspects including the reactions. In the following sections, each of these characteristics will be discussed in terms of basic fundamentals and design aspects. 

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