Abstract:
A method of joining pipes to produce an underwater pipeline on a firing line includes supplying the firing line with pipes having previously roughened end portions; welding the end portions of adjacent pipes to form cutbacks, each of which is defined by two end portions, and by an annular weld bead between the two end portions; cleaning, by cryogenic blasting, the outer surface of each cutback; and forming a protective joint coating about each cutback.
Abstract:
A method of abandoning or recovering an underwater pipeline from a laying vessel includes the steps of looping a first rope about a pulley connected to the free end of the pipeline; end-locking the first rope, on one side, to the laying vessel; and winding or unwinding the first rope, on the other side, by means of a first winch located on the laying vessel.
Abstract:
A laying ramp for laying a pipeline on the bed of a body of water can include an elongated frame having a first and second end; connecting members connecting the first end of the elongated frame to a vessel; at least one guide device fitted to the elongated frame to guide the pipeline along the elongated frame; and a support assembly, which has at least one undercarriage to roll along the bed of the body of water and support the second end of the elongated frame.
Abstract:
A method of forming a protective coat about a cutback between pipes forming part of an underwater pipeline provides for laying a thermoplastic sheet on a supporting sheet; and winding the thermoplastic sheet and the supporting sheet about the cutback to join the thermoplastic sheet to the cutback.
Abstract:
The present invention relates to a process for the recovery of ammonia contained in a gaseous stream, said process comprising the following phases: (a) subjecting the gaseous stream containing ammonia to a washing with an aqueous washing solution having a pH lower than 7.0, with the formation of a purified gaseous stream and an aqueous solution containing an ammonium salt; (b) treating the aqueous solution containing the ammonium salt coming from phase (a) in a vertical falling film heat exchanger at a temperature from 50 to 250° C. and an absolute pressure ranging from 50 KPa to 4 MPa with the formation of a regenerated washing solution and a gaseous stream comprising NH3 and H2O; (c) recycling said regenerated washing solution to phase (a). The present invention also relates to equipment for effecting the above process.
Abstract:
The present invention relates to a welding torch that includes an electrode (3) that has a longitudinal groove (9) formed therein which guides a welding wire (4) which is fed form a laterally spaced-apart location. The electrode (3) is open and the wire (4) is supported on one side only. In the region of the welding tip, the electrode (3) is elongate and the cross-sectional area is smaller than the area at a position further from the tip. Regions between an outer housing (11) and a main support body (2) define two shielding gas conduits positioned on opposite sides of the body (2), through which gas flows and then combines to form a unitary stream. The body (2) contains cooled regions which are supplied with cooling fluid by a conduit (7) and removed by conduit (8), parts of which are positioned between the shielding gas conduits close to the welding electrode (3).
Abstract:
Two pipes are arranged end to end, the pipes being shaped such that a groove is defined between the ends of the pipe. A plurality of welding torches are used to weld in the groove, such that at least some of the welding torches perform a first welding pass, the welding characteristics of the torches are adjusted and at least some of the welding torches are used to perform a second welding pass. At least one torch welds in a first sector in the first welding pass and a second sector in the second welding pass, the second sector being different to the first. The sectors might overlap or might not overlap.
Abstract:
A monohull vessel for laying a pipeline includes tensioners 13 disposed along a Pipelaying path P. The pipelaying path P includes an upstream portion that is substantially horizontal and at least 10 m above the centre of rolling R of the vessel and, towards a stern end of the vessel hull, a downstream portion that is downwardly inclined and, in use, enters the water at a location inboard of the stern end of the vessel hull 1.
Abstract:
A method of joining pipes (3) to produce underwater pipelines (2), wherein the facing free ends (15) of two adjacent pipes (3), aligned along an axis (A), are welded to define a cutback (18); a protective sheet (22) of plastic material is extruded close to the cutback (18); and the protective sheet (22) is wound about the cutback (18).
Abstract:
Process for the production of alkyl ethers by the etherification of isobutene, contained in C4-C5 hydrocarbon streams, with linear alcohol, in the presence of acid catalysts, comprising the following essential steps: a) feeding the isobutene contained in C4-C5 hydrocarbon cuts, together with one or more streams containing linear alcohol, to a first reaction step; b) sending the stream leaving the first reaction step to a first distillation area, separating a light stream from a heavy stream containing the desired ether; c) feeding the light stream separated in the first distillation area, together with one or more streams containing linear alcohol, to a second reaction step; d) sending the stream leaving the second reaction step to a second distillation area separating a light stream from a heavy stream containing ether, C4 hydrocarbons and alcohol which is recycled to the first distillation area; e) sending the light stream in the second distillation area to a recovery section of the linear alcohol contained therein; f) recycling the linear alcohol recovered in the recovery section to at least one of the two reaction steps. The present invention relates to plant solutions which allow the alcohol/isobutene molar ratio to be increased in the reaction steps and therefore maximizing the conversion of isobutene.