Abstract: The invention relates to an improved premix burner and a method of its operation for combustion with a minimum of NO.sub.x emissions. The improvement is achieved by combining staged combustion with a premix burner in a manner such that mixing of the secondary air with the flame is delayed.

Abstract: As an improvement in an anti-surge control method for a multi-stage centrifugal compressor having interstage coolers, this invention comprises, when there is an imbalance of stage flows relative to surge, replacing recycle with warm expanded gas to the maximum extent possible that still achieves an energy saving as compared with not effecting such replacement.

Abstract: Apparatus and method for substantially blocking the "line-of-sight" between a radiant section of a furnace and a convection section positioned above the radiant section, while at the same time permitting flue gases from the radiant section to travel substantially freely through the shield. The shield may be composed of a plurality of staggered bodies. In a preferred embodiment the bodies are staggered plates, composed of insulating material. The staggered plates are supported by hangers that are hung from convection tubes in the convection section. In another embodiment the staggered bodies are tubes or rods.

Abstract: A unique combustion system is described which improves the aerodynamic pattern associated with the combustion gases inside a pyrolysis furnace. The resultant pattern is very stable, creates minimum flame impingement on the process tubes, and ensures a very high mixing level throughout the reactor.

Abstract: The invention relates to quenching a cracked hydrocarbon gas by passing a cracked gas stream axially through a pipe and injecting a liquid coolant into said pipe through a plurality of circumferentially arranged slots in a swirling manner, the weight ratio of the flow rate of the coolant to the flow rate of the gas stream being in the range of about 2 to about 15 whereby a sufficient amount of the coolant is swept into the gas stream to effectively cool the same. Suitable apparatus comprises a quench pipe formed of two substantially abutting sections, the downstream section being grooved to form with the upstream section of said slots. Preferably the upstream section has an internal circumferentially arranged deflector lip overhanging the slots.