Complex sentence: A chemical plant commonly has usually large vessels or sections called units that are interconnected by piping or other material-moving equipment which can carry streams of material such as fluids (gas or liquid carried in piping) or sometimes solids or mixtures such as slurries.
Split into simpler sentences: A chemical plant commonly has usually large vessels or sections called units that are interconnected by piping or other material-moving equipment which can carry streams of material. Such material streams can include fluids (gas or liquid carried in piping) or sometimes solids or mixtures such as slurries.