Propane, mixing ratios

Liquefied petroleum gas (LPG) was used as fuel for the first time in the USA in 1912. Under the general term natural gas liquids (NGL), 60% of global LPG originates as a fraction separated from methane during the production of oil and gas the remaining 40% are generated as a by-product from the fractionated distillation of crude oil in refineries. Liquefied petroleum gas is a mixture of propane and butane, with the mixing ratio dependent on the country and season. 

Flame treatment consists of exposing a surface to a flame for a time of less than several seconds. The gas bnmers are fed from the mains (chief component methane) or bottled gas (propane or bntane). Of importance in the operation of a flame treater is the gas to air mix ratio. A slight excess of oxygen over that required for complete combustion is recommended. Depending on the level of gas in the mix, the flame can have substantially different characteristics. A surface is typically exposed to the flame region just above the blue cone until it becomes glossy. 

Later, real-time measurement of Bt2 and BrCl were made by CIMS in ALERT2000 campaign, and their maximum mixing ratios were obtained to be 27 and 35 pptv, respectively, while CI2 could not be observed over the detection limit of 2 pptv (Foster et al. 2001 Spicer et al. 2002). On the other hand, the evidence of the major role of Cl atoms instead of OH radicals in the consumption of hydrocarbons in the period of low O3 was found by Jobson et al. (1994), and the presence of Cl atoms in the low O3 plume has been proved. Figure 7.22 is the plot of i-butane/n-butane against i-butane/propane ratio for the low ozone and normal ozone period (Jobson et al. 1994). The rate constants of i-butane and propane for... 

The peroxybutanoyl radical, formed following abstraction at the 1-position and reaction with O2, reacts with NO2 to form peroxybutanoyl nitrate (PBN). At 298 K, the lifetime for dissociation of PBN to regenerate peroxybutanoyl and NO2 is about 45 min. even for an NO2 mixing ratio of only 100 pptv, the ratio of [PBN] [peroxybutanoyl] is 80 at equilibrium and the timescale for establishment of the equilibrium is only 30 s. Reaction of PBN with OH to form propanal has a timescale of about 2.5 days for [OH] = 10 moleculecm , and so is not competitive. The peroxybutanoyl radical also reacts with NO, on a timescale of about 20 s for an NO mixing ratio of 100 pptv and forms the propyl radical and CO2. After reaction with O2 and then NO, this reaction channel leads to formation of propanal. 

A.ntioxidants. PhenoHc antioxidants, added at about 0.1—0.5 phr, are usually chosen from among butylated hydroxytoluene [128-37-0] (BHT), and Nnonylphenol [104-40-5] for Hquid stabilizer formulations and bisphenol A [80-05-7] (2,2-bis-(/)-hydroxyphenyl)propane) for the soHd systems. Low melting thioesters, dilauryl thiodipropionate [123-28-4] (DLTDP) or distearyl thiodipropionate [693-36-7] (DSTDP) are commonly added along with the phenoHcs to enhance their antioxidant performance. Usually a 3 1 ratio of thiodipropionate to phenoHc antioxidant provides the desired protection. Most mixed metal stabilizer products contain the antioxidant iagredient. 

The difference in behavior reported by Von Stackelberg is not thought to be an essential one. Whether decomposition of a hydrate containing two solutes by removal of its vapor through pumping will be a univariant process depends on the number and compositions of the phases formed. In the system of Fig. 10, for instance, a mixed HtS-propane hydrate will exhibit a constant decomposition pressure on pumping at — 3°C if it contains HaS and propane in the azeotropic" ratio of approximately 3 1. 

Pillai and Pines (84) found that neopentyl alcohol, mixed with 10% by weight of piperidine and passed over alumina prepared from aluminum isopropoxide, yielded 2-methyl-l-butene and 2-methyl-2-butene, in a maximum ratio of 3, and small amounts of 1,1-dimethylcyclo-propane. However, lert-pentyl alcohol yielded these two olefins in a maximum ratio of only 1.4, and none of the cyclopropane was produced (Table VI). Because of these facts a carbonium ion mechanism which is applicable to ferf-pentyl alcohol is not adequate to explain the rearrangement taking place during the dehydration of neopentyl alcohol,... 

In one continuous method (17), the waxy oil charge—for example, in the case of a topped crude—is diluted with an equal volume of propane and the mixture is chilled to about —25° F. by means of heat exchange with cold filtrate in double-pipe scraped-surface equipment. This chilled mixture is then mixed with propane which has been chilled by autorefrigeration to —45° F. to bring the ratio of propane to oil to about 5 to 1. Ninety per cent of the refrigeration required is accomplished in this manner the remaining 10% is obtained by evaporating propane from the diluted mixture. 

Propane is stored underpressure to keep it liquid. Unlike LNG, propane does not need anything other than a modest pressure to keep it liquefied. The tanks that store propane are pressure vessels, but since they can be made from low-carbon steel their price is modest compared to CNG and LNG tanks. The propane is vaporized in a device called the converter that lowers the pressure of the propane to vaporize it. The converter also uses engine coolant to warm the propane to ensure that it is completely vaporized when it passes on to the mixer. As its name suggests, the mixer mixes the propane and air in the desired ratio before it enters the engine. Other controls and compensation for temperature are included in the propane fuel system. Propane fuel systems can also incorporate feedback control to work with three-way catalyst emission control systems. 

Acetonitrile can be produced by catalytic ammoxidation of ethane and propane over Nb-Sb mixed oxides supported on alumina, with selechvities to acetonitrile of about 50-55% at alkane conversions of around 30% [133]. In both cases, CO forms in approximately a 1 1 molar ratio with acetonitrile, owing to a parallel reaction from a common intermediate. When feeding n-butane, the selectivity to acetonitrile halves. Bondareva and coworkers [134] also studied ethane ammoxidation over similar types of catalyst (V/Mo/Nb/O). 

Catalysts were tested in a fixed bed quartz tubular reactor, at atmospheric pressure, in the temperature interval 500-600 C [2]. The catalyst (particle size 0.42-0.59 mm) were mixed with SiC of the same size at a catalyst/SiC volume ratio of 1/4. The feed consisted of a mixture of alkane/oxygen/helium in a molar ratio of 4/8/78 (ethane, propane) and 5/20/75 (n-butane). In order to achieve a similar alkane conversion, samples of 0.7-1.7 g and total flow of 100-200 ml min were used to modify the contact time (W/F). 

Refinery ethylene is usually made by the catalytic cracking of ethane, propane, or a mixed hydrocarbon stream, such as recovered natural gas liquids, naphthas, or gas oil [11]. Cracking conditions are quite severe 750-900°C and 0.1-0.6 second residence time for a low partial pressure hydrocarbon stream. A number of metal oxide catalysts have recently been evaluated for this purpose [12]. The usual diluent is steam, used at a weight ratio of steam to hydrocarbon of 0.2 1 for ethane feed, to progressively higher ratios with the higher molecular weight hydrocarbons of up to 2.0 1 for gas oil. 

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