Pre-treatment of mixtures containing crude aromatics

The most important sources for BTX aromatics are reformer gasoline, pyrolysis gasoline and coke oven benzole. Reformer gasoline is the major source in countries where the production of ethylene is primarily based on gas, so that production of pyrolysis gasoline is relatively low this applies particularly to the United States, where around two-thirds of its ethylene is produced from wet natural gases. With a share of around 75%, reformer gasoline is therefore the major raw material for BTX aromatics in the USA. 

The composition of reformer gasoline is naturally dependent on the original feedstock and on reforming conditions. Table 4.1 shows the composition of a typical reformer gasoline. 

Owing to the relatively low benzene content of reformer gasoline, in the USA in particular, toluene and xylene are converted to benzene, to meet the demand. 

Pyrolysis gasolines from mild cracking severe cracking 

Unlike reformer gasoline, pyrolysis gasoline cannot be used directly for the production of aromatics. It must first undergo a hydrogenation process to remove olefins and diolefins, together with sulfur compounds, so that aromatics can be produced to specified purity. 

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