Snamprogetti

Asnaprogetti S.p.a.

Francesco Saviano

Vincenzo Lagana

Vincenzo Lagana'

Domenico Sanfilippo

Giorgio Pagani

Virginio Cavallanti

Giorgio Fusco

Stanislao Ferrantino

Carmen Pirovano

Stanislad Ferrantino

Piero Bisi

Laura Piovesan

Process for the separation of light olefins from paraffins contained in mixtures, optionally also containing hydrogen, comprising bringing said mixtures into contact with an aqueous solution of one or more compounds of silver, preferably silver nitrate, and one or more ferric compounds, preferably ferric nitrate.

Process for the separation of light olefins from paraffins

A process for recovering power is disclosed, by which excess electric power is exploited for electrolyzing alkali metal hydroxides (molten) and the thusly obtained pure alkali metals are stored. When the demand of electric power becomes critical, the alkali metals are reconverted into their hydroxides and the reaction heat, along with the hydrogen produced in the reaction, is recovered to produce steam: the latter can be used either to produce electricity, or to use its heat, or both.

Process for storing and producing power by storage of alkali metals

An improved process is disclosed for preparing gases containing hydrogen and nitrogen and which is especially suitable for the synthesis of ammonia. Using natural gas or virgin naphtha as the starting materials, the reforming reaction with steam takes place in two serially arranged stages, the first of which occurs at an inlet temperature of from 400.degree. C. to 650.degree. C. and an exit temperature of from 650.degree. C. to 750.degree. C., a conversion of from 20% to 50% being effected, the second stage working at an exit temperature of from 750.degree. C. to 850.degree. C. and the conversion being increased up to 70%. Air reforming is carried out under conditions at which the exit temperature of the gas is between 920.degree. C. and 1050.degree. C. and the sensible heat of the effluent gases from the air reforming at such temperature condition is employed to activate the second steam reforming stage. Tube bundle heat-exchangers, the tubes of which are filled with an appropriate catalyst, are used.

Process for the preparation of gases which contain hydrogen and nitrogen

Decarbonation of gases with solutions of alkali metal carbonates and with alkanolamine solutions is improved by exploiting the heat of the vapors exiting the head of the alkanolamine solution regeneration column and also the heat of fluids condensed at the head of the regeneration column for the alkali metal carbonate solution. A very favorable heat balance is achieved and considerable power savings.

Process for the decarbonation of gases

A methanation reactor to be used preferably in an integrated urea-ammonia process for methanizing carbon oxides is disclosed in which the catalyst bed and an underlying heat exchanger of the tube-bundle type make up a unit mounted centrally of the reactor casing with a gap left between the reactor casing inside wall and centrally mounted unit. Fresh gases to be methanized enter the gap, then into the heat exchanger from below and flow upwards to the catalyst bed and thereafter flow down to the exchanger again. Incoming gases sweep the exchanger tubes from the outside, while the reacted gases flow in the interior of the tubes of the exchanging boundle. Particular blanket and a gland-seal system is provided to minimize the escape of gaseous fluids from the reactor.

Gland seal system for use with a methanation reactor

In an integrated or combined process for the production of ammonia and urea, the improvement consisting in that the absorption of CO.sub.2 from the raw gas going to the synthesis reactor for ammonia is carried out with an absorption apparatus which is divided into two sections, one being of the plate type and the other of the thin film type. The predominant fraction of CO.sub.2 is stripped in the thin-film section, the remainder in the adiabatic plate section.

Combined process for the production of urea and ammonia

A methanation reactor, to be used preferably in an integrated urea-ammonia process for methanizing carbon oxides is disclosed, in which the catalyst bed and an underlying heat exchanger of the tube-bundle type make up a unit mounted centrally of the reactor casing with a gap left between the reactor casing inside wall and said centrally mounted unit. Fresh gases to be methanized enter the gap, then the heat exchanger from below and flow upwards to the catalyst bed, whereafter they flow down to the exchanger again. Incoming gases sweep the exchanger tubes from the outside, while the reacted gases flow in the interior of the tubes of the heat exchanging bundle. Insulation blankets and gland seals are provided.

Methanation reactor

An integrated ammonia-urea process is disclosed which uses as the starting gas mixture a stream coming, for example, from steam reforming of hydrocarbons, carbon dioxide being stripped from the stream by the action of a very concentrated ammonia solution (above 70% by wt) first and the the action of an ammoniated solution of ammonium carbonate secondly, a solution of ammonium carbamate being obtained together with a gas stream composed of nitrogen and hydrogen; sending the carbamate solution to the urea reactor, discharging from the urea reactor the urea solution containing unconverted carbamate and excess ammonia, decomposing said carbamate and sending evolved ammonia to the urea reactor again along with carbon dioxide, discharging the urea solution having now 50% of the original carbamate to an adiabatic stripper in which the stripping gas is essentially composed of hydrogen and nitrogen, removing ammonia and carbon dioxide with water from the adiabatic stripper and condensing ammonia and carbon dioxide by heat exchange, sending the stream of hydrogen and nitrogen to methanization and ammonia synthesis and concentrating the urea solution directly until obtaining a urea melt.

Integrated ammonia-urea process

An improvement of the SNAM ammonia-stripper integrated urea process is disclosed, wherein a gaseous stream obtained by decomposing hydrocarbons is fed to an adiabatic ammonia stripper placed downstream of a carbamate decomposer, the adiabatic stripper also receiving a solution of urea which is rich in ammonia coming from the carbamate decomposer. The thus enriched gaseous stream (NH.sub.3, CO.sub.2, H.sub.2 O) is processed in a CO.sub.2 -absorber (or carbamate reactor) and the process proceeds in the urea synthesis reactor. Recycling and recovery loops are provided between the several reaction and/or decomposing units. Surprisingly, enough, the stripping on NH.sub.3 and CO.sub.2 takes place adiabatically and the drop of the CO.sub.2 partial pressure in the stream fed to the carbamate reactor has no bearing on the efficiency of the carbamate conversion which, according to the current technical teachings, requires an increase of the CO.sub.2 partial pressure.

Growing community of inventors

Segrate, Italy

Francesco Saviano