Abstract: A reverse cycle steam compression thermal machine is described, concerning a main circuit (100) connected to an auxiliary circuit (200), comprising an economizer (3), the main circuit (100) comprising a first high pressure exchanger (2) and an evaporator (5), the auxiliary circuit (200) comprising a second high pressure exchanger (7a) and a second expander (8); the economizer (3) includes a first hot branch (1c), a first cold branch (1f), a second hot branch (2c) and a second cold branch (2f).

Abstract: In the process for the purification of water by flocculation, a porous granular material is used as a decantation accelerator and is preferably constituted by pyroclasts which can act as a substrate for a bacterial growth which achieves biological purification together with the chemico-physical purification of the flocculation.

Abstract: Production of cumene by alkylation of benzene with propylene on a solid phosphoric acid catalyst, using a first step with a plurality of catalyst beds in series and a second step with a single catalyst bed, using an overall benzene/propylene molar ratio of at least 6:1, continuously delivering the benzene to the first bed, continuously delivering a series of streams of liquid propylene respectively to the first bed and, in the form of a cold stream, between each pair of contiguous beds, and using a benzene/propylene molar ratio higher than 16:1 at the inlet of each bed of the first step, and higher than 25:1 at the inlet of the bed of the second step.

Abstract: Butyl rubber is prepared by polymerizing isobutylene and a conjugated diolefin in a liquid reaction medium wherein the temperature is controlled by indirect heat-exchange with boiling ethylene admixed with a gas which is inert towards ethylene, the said boiling ethylene being subjected to a controlled pressure maintained at a value not lower than atmospheric.

Abstract: In a biological water purification process dirty water such as sewage percolates through a submerged bed of activated carbon under aerobic conditions, the carbon particle size and the water flow rate being such that the time of contact of the water with the mass of carbon above an intermediate level of the bed is at least thirty minutes, oxygenation air being blown into the bed at this intermediate level so that the mass of carbon below this level remains substantially free of active colonies of bacteria. The bed can be reactivated as desired by flushing with clean water and then with dirty water to re-establish bacterial colonies.