RU99123927A - METHOD FOR BURNING RICH GAS-HYDROCARBON GAS FLOW - Google Patents

Claims (9)

1. A method of burning a hydrocarbon-rich stream, in particular a natural gas stream, by indirect heat exchange with refrigerants in cascading cycles with mixtures of such refrigerants, characterized in that the cascade consists of at least three cycles with mixtures of refrigerants having different compositions .  2. The method according to claim 1, characterized in that the first of three cycles with a mixture of refrigerants serves for pre-cooling (E1), the second cycle with a mixture of refrigerants serves for liquefaction (E2), and the third cycle with a mixture of refrigerants serves for subcooling (E3) hydrocarbon-liquefied stream (1).  3. The method according to claim 1 or 2, characterized in that the mixture of refrigerants of the first of three cycles (P5, P10, ...) contains mainly 0 to 40 mol.% Ethylene or ethane, 30 to 40 mol.% Propane and 20-30 mol% of butane.  4. The method according to any one of the preceding paragraphs, characterized in that the mixture of refrigerants of the second of three cycles (L5, L6, ...) contains mainly 5 to 15 mol.% Methane, 0 to 80 mol.% Ethylene or ethane and 10 to 20 mol.% Propane.  5. The method according to any of the preceding paragraphs, characterized in that the mixture of refrigerants of the third of three cycles (S5, S6, ...) contains mainly 0 to 10 mol.% Nitrogen, 40 to 65 mol.% Methane and 0 to 40 mol% of ethylene or 0 to 30 mol% of ethane.  6. The method according to any one of the preceding paragraphs, characterized in that the preliminary cooling (E1), liquefaction (E2) and supercooling (E3) of the liquefied hydrocarbon-rich gas stream (1) is carried out in at least three heat exchangers (E1, E2, E3) and the decompressed mixture of refrigerants of each of the three cycles before re-compression (P3, L3, S3) is passed only through the last heat exchanger (E1, E2, respectively E3).  7. The method according to any one of the preceding paragraphs, characterized in that the compression of the mixtures of refrigerants is carried out using compressors (P3, L3, S3) with cold absorption.  8. The method according to any one of the preceding paragraphs, characterized in that the compressors (P3, L3, S3) used to compress mixtures of refrigerants drive only one drive (G), in particular from a gas turbine drive.  9. The method according to any one of the preceding paragraphs, characterized in that when the installation or process is stopped, at least a mixture of refrigerants of one of the cycles is accumulated in an intermediate manner in at least one separator / storage tank (P11, L7 and S8), which, respectively, which is located (s) at the coldest point of each cycle with a mixture of refrigerants.