Pyrolysis Output Characteristics

If the contact time is very short it limits the secondary reaction, which contributes to gas and coke. This results in a reduction of quantity and quality of gas and coke. 

The cracking mechanism of polymers follows first-order kinetics. 

Gaseous products include LPG range gases liquid products include liquid hydrocarbons solids include coke/residue. The average composition and properties of the output products depend upon the following factors. 

Operating condition can have a great impact on the properties of liquid output, its composition as well as the overall percentage output of solid, liquid and gaseous product. When the temperature is increased, rate of reaction increases. Approximately for every 40°C rise in temperature, the decomposition rate doubles. 

When the reactor pressure is high, then the residence time also increases which results in more unsaturation in the product and hence lower octane number of the gasoline is obtained. When the reaction is carried out at atmospheric pressure, shorter contact time reduce the chances of secondary cracking and hydrogen transfer reactions, thereby increasing the olefinity in the liquid product. 

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Gas oil cracking has all of the characteristics of naphtha cracking. The typical statistics are given in Table 9.4. Relative to naphtha, the gas oil cracking requires considerably more feed for the same ethylene output (500 kt/y) and at the same time produces increased volumes of pyrolysis gasoline and more particularly pyrolysis fuel oil. This requires an increase in the fixed capital to naphtha for the same scale of operation. 

Different grades of pyrolysis oil were burned at 4 MW nominal power output in a test furnace of Oilon Oy s R D Centre. Operation, dimensions, adjustment parameters, and characteristics of pyrolysis oils were tested and compared, and ertussions in different cases were measured. 

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