There is clear trend for high-pressure trains of a larger size. For a given plant size it reduces the number of trains with the corresponding savings in installation costs. Furthermore, fewer, larger trains generally mean less capital than more, smaller trains. Larger units have, inherently, higher efficiency. There is a preference amongst plant designers and operators for trains capable of operating reliably without pressure lubrication. Today this limits the train size to, approximately, 10,000 m(3)/d, considering a 40-45% conversion rate. Reliability, availability, dependability are paramount. Metallurgy with proven track record, adequate material combination, reasonable cost and case of processing is the key to the success of the installation.