Abstract: Methods for manufacturing brazed aluminum heat exchangers involved in boiling and condensing, including a high performance nucleate boiling surface bonded with the walls of fin-less boiling passages. One method includes providing a first heat exchanger core subassembly including a first joinable end, at least one cooling and one boiling passage, and a first partial finless passage arranged at the joinable end. A second heat exchanger core subassembly is provided similar to the first including a second joinable end. The first and second heat exchanger core subassemblies are brazed. The first joinable end is affixed, preferably by welding, to the second joinable end and the first partial finless passage is affixed to a second partial finless passage to form a coupled finless passage, and thereby a heat exchanger core.

Abstract: Disclosed is a heat exchanger comprising a boiling passage and cooling passage defined by opposite sides of metal walls. Layers of brazing material between the metal walls and a spacer member bond components of the heat exchanger together. An enhanced boiling layer (EBL) comprising metal particles bonded to each other and to a boiling side of the metal wall provides nucleate boiling pores to improve heat transfer. The EBL has a melting temperature that is higher than the melting temperature of the brazing material. Also disclosed is a process for assembling the heat exchanger.

Abstract: Disclosed is a heat exchanger comprising a boiling passage and cooling passage defined by opposite sides of metal walls. The heat exchanger is made with high strength alloys of aluminum that have improved creep resistance that maintain tensile strength and yield strength after use in this invention. Layers of brazing material between the metal walls and a spacer member bond components of the heat exchanger together. An enhanced boiling layer (EBL) comprising metal particles bonded to each other and to a boiling side of the metal wall provides nucleate boiling pores to improve heat transfer. The EBL has a melting temperature that is higher than the melting temperature of the brazing material. Also disclosed is a process for assembling the heat exchanger.

Abstract: Disclosed is a heat exchanger comprising a boiling passage and cooling passage defined by opposite sides of metal walls. Layers of brazing material between the metal walls and a spacer member bond components of the heat exchanger together. An enhanced boiling layer (EBL) comprising metal particles bonded to each other and to a boiling side of the metal wall provides nucleate boiling pores to improve heat transfer. The EBL has a melting temperature that is higher than the melting temperature of the brazing material. Also disclosed is a process for assembling the heat exchanger.

Abstract: Disclosed is a heat exchanger comprising a boiling passage and cooling passage defined by opposite sides of metal walls. Layers of brazing material between the metal walls and a spacer member bond components of the heat exchanger together. An enhanced boiling layer (EBL) comprising metal particles bonded to each other and to a boiling side of the metal wall provides nucleate boiling pores to improve heat transfer. The EBL has a melting temperature that is higher than the melting temperature of the brazing material. Also disclosed is a process for assembling the heat exchanger.

Abstract: Methods for manufacturing brazed aluminum heat exchangers involved in boiling and condensing, including a high performance nucleate boiling surface bonded with the walls of fin-less boiling passages. One method includes providing a first heat exchanger core subassembly including a first joinable end, at least one cooling and one boiling passage, and a first partial finless passage arranged at the joinable end. A second heat exchanger core subassembly is provided similar to the first including a second joinable end. The first and second heat exchanger core subassemblies are brazed. The first joinable end is affixed, preferably by welding, to the second joinable end and the first partial finless passage is affixed to a second partial finless passage to form a coupled finless passage, and thereby a heat exchanger core.

Abstract: A heat exchanger has a boiling passage and a cooling passage defined by opposite sides of metal walls. Layers of brazing material between the metal walls and a spacer member bond components of the heat exchanger together. An enhanced boiling layer (EBL) having metal particles bonded to each other and to a boiling side of the metal wall provides nucleate boiling pores to improve heat transfer. The EBL has a melting temperature that is higher than the melting temperature of the brazing material.

Abstract: A process for the production of C.sub.8 and higher olefins by the oligomerization of light olefins to heavier olefins is improved by the addition of cycloparaffins to the oligomerization zone. The recycle of the cycloparaffins extends the catalyst activity and improves the catalyst life. Cyclohexane provides an excellent solvent for removing deposits from the catalyst with chemical inertness to the process and a boiling range that allows its essentially complete recovery when producing nonenes and higher olefins from propylene feeds.

Abstract: A process for the reforming of hydrocarbons is improved by the use of an enhanced nucleate boiling surface in a selected portion of the feed effluent heat exchanger. In a vertical type heat exchanger where the reforming feedstream enters at a lower end of the heat exchanger and is at least partially vaporized in the heat exchanger by contact with a reforming effluent stream that enters an upper end of the heat exchanger and is at least partially condensed therein, an enhanced nucleate boiling surface is formed on the heat exchange surface that is in contact with the entering liquid phase portion of the stream feed. The enhanced nucleate boiling surface increases the amount of condensing that takes place on the opposite side of the heat exchange surface in a boiling-condensing zone.

Abstract: This invention pertains to the field of producing ammonia. More specifically, the present invention relates to reducing the costs of producing a unit amount of ammonia, particularly the energy costs, by the utilization of an enhanced boiling surface in the refrigeration zone of the process.

Abstract: The present invention is directed to an improvement in an alkylation process involving effluent refrigeration in which an enhanced boiling surface heat exchanger is utilized in the alkylation reaction zone so as to carry out the reaction at its optimum reaction temperature and at a positive compressor suction pressure.