It is appropriate that the subject of petrochemicals should be discussed at a gathering of people such as yourselves who are participating in the management and development of the petroleumindustry, even though petrochemicals still play such a minor role as outlets for refinery petroleum streams and natural gas. Knowing the vast quantities in which your products are produced and consumed, it may be difficult for you to take the petrochemical industry seriously – petrochemicals are thought of in terms of millions of pounds rather than billions ofbarrels or trillions of cubic feet.
Even though the volumes of petrochemicals produced and used are insign1ficant when compared tothe quantities of petroleum and natural gas consumed, the 11nes of demarcation between the petroleum and natural gas industries and the petrochemical industry are fading away, the entire world is fast becoming as dependent upon petrochemicals asit has become on petroleum and natural gas for its energy. and in the industrially-developed countries of the world the dependence upon petrochemicals is irreversible.
It would have been convenient if the man who first used the term "petrochemical" had defined it explicitlybecause as it is used today it is unwieldy, to say the least; "petrochemical" is used to refer to almost anything and everything, other than fuels and lubricants, either extracted from or derived frompetroleum and natural gas. Elemental sulfur and sulfuric acid could be considered to be "petrochemicals"since the former is recovered from natural gas and the latter is produced from the byproduct hydrogen sulfide obtained during petroleum refining. The carbon black that serves as a reinforcing agent for rubber could also be considered to be a petrochemicalsince it is made by burning liquid hydrocarbons as well as natural gas. Even the final end products such as the synthetic fibers are sometimes included in the category of petrochemicals.
It is probably best, however, to confine the definition of petrochemicals so that it includes
the aromatics isolated from petroleum streams
the olefins channeled to the manufacture of chemicals (these olefins are either obtained as byproducts at petroleum refineries or are intentionally produced by dehydrogenating orcracking natural gas liquids, condensates, naphtha, or gas oil)
the chemical derivatives of methane such as ammonia and methyl alcohol
the intermediates, such as acetic acid and ethyl chloride, that are made by the partial oxidation or chlorination of lower paraffins, and
all the derivatives of all of these up to the point where they will not undergo further chemical change prior to use.
Even this definition of "petrochemica1s" can be somewhat unmanageable. The following flow-charts, that show how the basic petrochemical hydrocarbonsprovide the products that are ubitiquitous, have been condensed so that they include only the first-generation derivatives of each; the numerous petrochemical intermediates from which the end-products are eventually derived have been omitted.
Between the first-generation derivatives of methane (Figure 1) and the consumer products made from it are at least 85 petrochemical intermediates.