Method of liquefying a contaminated hydrocarbon-containing gas stream
View Patent ↗A method of liquefying a contaminated hydrocarbon-containing gas stream includes cooling the stream in a first heat exchanger and cooling the cooled stream in an expander to obtain a partially liquefied stream. The method further includes separating the partially liquefied stream in a separator to obtain a gaseous stream and a liquid stream. The liquid stream is expanded to obtain a multiphase stream containing at least a vapour phase, a liquid phase and a solid phase. The multiphase stream is separated in a separator to obtain a gaseous stream and a slurry stream. The slurry stream is separated in a solid/liquid separator to obtain a liquid hydrocarbon stream and a concentrated slurry stream. The gaseous stream is passed through the first heat exchanger to obtain a heated gaseous stream. The heated gaseous stream is compressed and combined with the contaminated hydrocarbon-containing gas stream.
1. A method of liquefying a contaminated hydrocarbon-containing gas stream, the method comprising at least the steps of:
(a) providing a contaminated hydrocarbon-containing gas stream;
(b) cooling the contaminated hydrocarbon-containing gas stream in a first heat exchanger thereby obtaining a cooled contaminated hydrocarbon-containing stream;
(c) cooling the cooled contaminated hydrocarbon-containing stream in an expander thereby obtaining a partially liquefied stream;
(d) separating the partially liquefied stream in a first separator thereby obtaining a first gaseous stream and a liquid stream;
(e) expanding the liquid steam obtained in step (d) thereby obtaining a multiphase stream, the multiphase stream containing a vapour phase, a liquid phase and a solid phase;
(f) separating the multiphase stream in a second separator thereby obtaining a second gaseous stream and a slurry stream;
(g) separating the slurry stream in a solid/liquid separator thereby obtaining a liquid hydrocarbon stream and a concentrated slurry stream;
(h) passing the first gaseous stream obtained in step (d) through the first heat exchanger thereby obtaining a heated gaseous stream; and
(i) compressing the heated gaseous stream thereby obtaining a compressed gas stream; and
(j) combining a first portion of the compressed gas stream obtained in step (i) with the contaminated hydrocarbon-containing gas stream provided in step (a);
(k) cooling a second part of the compressed gas stream obtained in step (i) through a second heat exchanger thereby obtaining a cooled compressed gas stream;
(l) expanding the cooled compressed gas stream thereby obtaining an expanded gas stream; and
(m) combining the expanded gas stream with the first gaseous stream obtained in step (d).
2. The method according to claim 1 , wherein the contaminated hydrocarbon-containing gas stream comprises at least 50 vol. % methane.
3. The method according to claim 1 , wherein the cooled contaminated hydrocarbon-containing stream obtained in step (b) has a temperature of at most −40° C.
4. The method according to claim 1 , wherein the multiphase stream obtained in step (e) has a temperature of at most −100° C.
5. The method according to claim 1 , further comprising: passing the second gaseous stream obtained in step (f) through the second heat exchanger thereby obtaining a second heated gaseous stream; compressing the second heated gaseous stream thereby obtaining a second compressed gas stream; and combining the second compressed gas stream with the heated gaseous stream obtained in step (h).
6. The method according to claim 1 , wherein the liquid hydrocarbon stream obtained in step (g) is stored in a storage tank, and wherein a boil-off gas stream from said storage tank is combined with the second gaseous stream obtained in step (f).
7. The method according to claim 5 , wherein the liquid hydrocarbon stream obtained in step (g) is stored in a storage tank, and wherein a boil-off gas stream from said storage tank is combined with the second gaseous stream obtained in step (f).