Chapter 3 - Chemical concepts used for engineering purposes

Abstract

This chapter explains some of the important chemical concepts used for engineering purposes, such as stoichiometry. It is commonly used to describe the way in which the components in a chemical reaction combine to form products. Thus, in the case of the fischer-tropsch (FT) process the stoichiometry is primarily concerned with the ratio of consumption of hydrogen and carbon monoxide, and in some cases also carbon dioxide. The other chemical concepts are: conversion, selectivity, synthesis gas composition and the FT reactions, conversion and selectivity evaluation, primary and secondary fractions, FT product distributions, selectivity at typical commercial conditions, and finally, FT selectivity control. It discusses that conversion performance relates to the consumption of reactants rather than the appearance of products. From the previous section on stoichiometry, it is clear that stoichiometric considerations may affect the relative amounts of the reactants that are consumed. The chapter also highlights that the term “kinetics” is generally applied to the equations used to deserve the rate of consumption of reactants and is thus, related to the prediction of conversion performance.