Propane propylene mixtures, pyrolysis

Table 1. Typical results in pyrolysis of propane—propylene mixtures...

If this equation Is also valid In the pyrolysis of propane-propylene mixtures, the amount of propylene available for the copyrolysls Is defined as the sum of the propylene fed plus propylene produced from propane evaluated from Equation (23). However, the selectivity was small and could be negligible In the case of low propane to propylene ratio In feed (yCoHo 0.2). Methane yield from propane and propylene was larger chan that of ethylene as shown In Table 1. This result will be caused by hydrogenation and hydrogenolysis of each component. 

Determination of Rate Constant In the Pyrolysis of Propane-Propylene Mixtures... 

Figure 2. Arrhenius plots for propane decomposition rate in pyrolysis of propane-propylene mixtures...

HARAGucm ET AL. Pywlysk of Propane-Propylene Mixtures Table 4. Reaction model for pyrolysis of propane... 

An attempt was made to calculate the product distributions of propane pyrolysis on the basis of the reaction model considering both inhibition and acceleration effects observed in the pyrolysis of propane-propylene mixtures. The reaction model for propane pyrolysis used in this work is shown in Table 4. The rate constants given in Table 4 were measured in our previous works (3, 4). At the initial stage of propane pyrolysis, the formation of the primary products such as methane, ethylene and propylene is predominant but as the reaction proceeds, the consecutive decomposition of each product is also remarkable. Therefore, a reaction model was postulated which consisted of major stoichiometric reactions for propane (i) - (iv), for propylene (v), (vi) and... 

Using the experimental results of the pyrolysis of propane-propylene mixtures under the conditions of temperatures near 900 C, atmospheric pressure and hydrogen dilution, the relation between the decomposition rate constant of propane or propylene and the ratio of both reactants was obtained. It was found from the results that propylene had an inhibition effect on propane decomposition, and conversely, propane had an acceleration effect on propylene decomposition. 

Propane and propylene were first pyrolyzed separately to determine general trends in the product distribution. The typical product distributions of the pyrolysis of propane and propylene mixtures are given in Table 1. The product distributions when the major reactant was propane or propylene were similar to those when propane and propylene were separately pyrolyzed, respectively. 

Reversed-phase hplc has been used to separate PPG into its components using evaporative light scattering and uv detection of their 3,5-dinitroben2oyl derivatives. Acetonitrile—water or methanol—water mixtures effected the separation (175). Polymer glycols in PUR elastomers have been identified (176) by pyrolysis-gc. The pyrolysis was carried out at 600°C and produced a small amount of ethane, CO2, propane, and mostiy propylene, CO, and CH4. The species responsible for a musty odor present in some PUR foam was separated and identified by gc (Supelco SP-2100 capillary column)... 

Significant products from a typical steam cracker are ethylene, propylene, butadiene, and pyrolysis gasoline. Typical wt % yields for butylenes from a steam cracker for different feedstocks are ethane, 0.3 propane, 1.2 50% ethane/50% propane mixture, 0.8 butane, 2.8 hill-range naphtha, 7.3 light gas oil, 4.3. A typical steam cracking plant cracks a mixture of feedstocks that results in butylenes yields of about 1% to 4%. These yields can be increased by almost 50% if cracking severity is lowered to maximize propylene production instead of ethylene. 

The cracked gases are compressed to 30 to 40 bar, freed from carbon dioxide and hydrogen sulfide and dried. Low temperature distillation at temperatures of — 30 to 140 °C effects separation into ethylene, ethane, propylene, propane, mixtures of C4- and Cs-hydrocarbons and light pyrolysis gasoline. This refining pro-... 

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