Abstract: A process for making ethylenically unsaturated hydrocarbons from a saturated C.sub.3 -C.sub.5 hydrocarbon feed with improved heat recovery. The feed is partially vaporized against hot discharge gases from product compressors, completely vaporized with low pressure steam and preheated against hot reactor effluent, before being heated by a process heater to reaction temperature and catalytically dehydrogenated in an adiabatic reactor. The process is controlled by regulating the low pressure steam supplied to the vaporizer, the heat input to the process heater, and cooling water flow to the process coolers.

Abstract: A skateboard comprises a single oversized centrally-located wheel in addition to conventional pairs of front and rear wheels. The wheels are arranged so that the board will ride on no more than three wheels at a time, with either the front or rear pair being elevated above the supporting ground surface, depending upon the rider's longitudinal weight distribution on the skateboard relative to the center wheel. An optional foot-operated friction brake is engageable with the center wheel.

Abstract: Diesel range fuel is produced in excess of gasoline range fuel from virgin hydrocarbon oils having low carbon content by heat soaking under mild thermal cracking conditions carried out at low pressure wherein the cracked fractions are removed substantially as they are formed.

Abstract: An apparatus for contacting fluids combined with solids comprises a cylindrical vessel with a slurry or liquid feed inlet port, a liquid outlet port, a gas inlet port and a gas outlet port. The vessel includes a lower cylindrical baffle which defines a stilling chamber therearound, the main contacting section of the vessel being above the stilling chamber. The lower end of the baffle extends below the liquid outlet port which discharges liquid from the stilling chamber. A cylindrical member is disposed in the cylindrical vessel inwardly of the stilling chamber. It has a lower end which is aligned with the gas inlet port for receiving gas therefrom and an upper end which is higher than a lower edge of the cylindrical baffle. The main contacting section above the cylindrical member has a height which makes a ratio with a length of the cylindrical member having a value within the range between 2 and 50.

Abstract: A hydrotreating reactor having a plurality of vertically spaced contacting stages having frusto-conical baffles for back-mixing hydrocarbon oil being treated and a plurality of clear oil outlets in fluid communication with a corresponding plurality of annular stilling chambers.