IMPIANTO DI LIQUEFAZIONE DEL METANO CON RELATIVO SISTEMA DI CONTROLLO DI PROCESSO

摘要

Plant for the liquefaction of natural gas, comprising a unit (S1A,S1B) for compression of the natural gas; a section (S2) for cooling of the natural gas; and a circuit (S3) for liquefaction which comprises a main line (l)-(2)-(3) traversed by a flow (ml) of gas and whereon a heat exchanger (H-EX) is installed; a secondary line (4) -(5) -(6) which branches off from the main line (l)-(2)-(3) and which comprises a valve (J-T Valve 2) through which a flow (m3) of gas is first laminated to a lower pressure (P3) and then led to traverse said heat exchanger (H-EX), cooling there a transiting flow (m2), difference between (ml) and (m3). Means of regulation and control are provided of the working conditions of subcooling of the flow (m2) of fluid which include a first temperature control valve (TC-Control Valve 1) which regulates the flow (m2) of fluid transiting along said main line (l)-(2)-(3), in relation with the final temperature (T2) required for said fluid, and a second pressure control valve (PC-Control Valve 2) which is installed on the secondary line (4) -(5) -(6) downstream of the valve (J-T Valve 2) and which regulates said secondary flow (m3) on the basis of a pressure (P3) detected on said secondary line (4) -(5) -(6) downstream of said valve (J-T Valve 2).