A contact tray has a tray deck for receiving a liquid stream and a plurality of valves distributed across the tray deck through which vapor ascends for interacting with the liquid stream. Each valve includes an opening in the tray deck, wall segments that extend upwardly along opposite sides of the opening, and a valve body. The valve body has a trapezoidal valve cover positioned in covering relationship above and extending outwardly beyond the opening and legs that are attached to the valve cover at recesses located at opposite ends of the valve cover. A vent is positioned in one of the legs.

A fractionation column can be used to separate a liquid containing multiple components into its constituent components based on vapor pressure. While the fractionation column may be designed for certain operational performance, the operational characteristics may change, for example, due to changed flow rates through the column and/or fouling in the column. In some examples, a fractionation column is described that includes a fractionation tray formed of multiple tray decks that move relative to each other. The tray decks can have apertures that move relative to each other between a position in which there is a comparatively large amount of open area through the fractionation tray to a position in which there is a comparatively small amount of open area through the fractionation tray. Movement of the trays can control turndown and/or clear fouling buildup on the tray surface.

A contact tray for use in a mass transfer column and having a tray deck for receiving a liquid stream and a plurality of valves distributed across the tray deck through which vapor ascends for interacting with the liquid stream. Each valve has an opening in the tray deck in the form of a central segment and extensions that extend outwardly from opposite ends of the central segment. The valves each include a valve body with a valve cover positioned in covering relationship above and extending outwardly beyond the opening and legs that are attached to the valve cover at recesses located at opposite ends of the valve cover. The legs extend downwardly through the extensions in the opening and include stops in portions of the legs positioned below the tray deck to permit limited vertical movement of the legs to allow the valve body to move between open and closed positions in response to ascending vapor pressure against an undersurface of the valve cover. Deflectors are positioned at opposite sides of the legs to restrict vapor passage around the legs.

A multi-pass contact tray for use in a mass transfer column has a mixture of fixed valves to movable valves, with the numbers of the respective valves being selected to balance the volumetric flow of vapor through deck segments when the vapor is ascending at volumetric flow rates insufficient to maintain the movable valves in an open position.

Multiple downcomer trays having increased active area for vapor-liquid contact and separation are described. The increased active area of the tray is achieved by adding raised bubble promoters surrounded by perforated vertical contactors on the tray deck. The bubble promoters and surrounding vertical contactors are located under the downcomers from the tray above. The bubble promoter and surrounding vertical contactor promote uniform fluid flow and contact.

The present disclosure relates to a valve tray for use in a chemical process column. The valve tray includes a plurality of apertures formed therein. A plurality of valves are maintained in a spaced relationship relative to individual apertures of the plurality of apertures. An area of the individual apertures is less than an area of individual valves of the plurality of valves.

A mass transfer assembly has at least one dividing wall, zones of mass transfer structures on opposite sides of the dividing wall, and a vapor flow restrictor that is operable to vary the split of vapor ascending through the zones of mass transfer structures on the opposite sides of the dividing wall.

Trays having increased capacity and efficiency are described. The trays have a deck, and downcomers extending through the deck. There are a plurality of bubble promoters on the deck. Each bubble promoter defines a zone on the deck, and the zone has an opening in the deck. The opening is positioned adjacent to a solid support for the tray. The bubble promoters provide areas through which vapor can passing, turning blocked areas of the tray into active areas. Mass transfer columns containing the trays are also described.

Multiple downcomer trays having increased active area for vapor-liquid contact and separation are described. The increased active area of the tray is achieved by adding raised bubble promoters surrounded by perforated vertical contactors on the tray deck. The bubble promoters and surrounding vertical contactors are located under the downcomers from the tray above. The bubble promoter and surrounding vertical contactor promote uniform fluid flow and contact.

A process for thermal cracking of a feedstock of plastic materials, in particular waste materials, includes the steps of melting the feedstock, conveying melted feedstock in a pyrolysis chamber where the melted feedstock is heated in a substantially oxygen purged environment, to convert it into pyrolysis gases, the process further comprising the steps of: driving pyrolysis gases from the pyrolysis chamber into a tray reflux column comprising a partial condenser at its upper extremity, returning pyrolysis gases condensed in the tray reflux column into the pyrolysis chamber, distilling pyrolysis gases exiting the partial condenser of the reflux column, to provide one or more fuel products.