Method and apparatus to start-up controlled freezing zone process and purify the product stream

A method for separating a feedstream containing carbon dioxide acid gas and methane comprising the steps of:

• feeding carbon dioxide containing methane to a lower distillation zone of a distillation column;
• producing in said lower distillation zone an enriched carbon dioxide liquid bottoms stream and a freezing zone vapor feedstream at a temperature and pressure at which substantially no carbon dioxide solids are formed;
• contacting said freezing zone vapor feedstream with at least one freezing zone liquid feedstream containing methane in a controlled freezing zone at a temperature and pressure wherein both solids containing carbon dioxide and a methane-enriched vapor stream are formed;
• separating said methane-enriched stream into liquid and vapor components;
• refluxing the liquid component of the methane-enriched stream to the column;
• and
• stripping the remaining acid component from the vapor component of the methane-enriched stream.

A method of transforming a distillation column with a controlled freezing zone from start-up conditions to after start-up operating conditions comprising the steps of:

• feeding at least one acid gas containing methane to a lower distillation zone;
• producing in said lower distillation zone an enriched carbon dioxide liquid bottoms stream and a freezing zone vapor feedstream at a temperature and pressure at which substantially no carbon dioxide solids are formed;
• contacting said freezing zone vapor feedstream with at least one freezing zone liquid feedstream containing methane in a controlled freezing zone at a temperature and pressure wherein both solids containing carbon dioxide and a methane-enriched vapor stream are formed;
• stripping the acid gas component from the stream to produce an acid gas stripped stream;
• separating said stripped stream into liquid and vapor components;
• refluxing the liquid component of said stripped stream to the distillation column;
• continuing the reflux of the distillation column until operating temperature has been achieved;
• redirecting the methane-enriched vapor stream from the stripping means to a separating means;
• separating the methane-enriched vapor stream into vapor and liquid components;
• stripping the remaining acid gas components from the vapor component of the methane-enriched vapor stream;
• and
• refluxing the liquid component of the methane-enriched vapor stream to the tower.

A method of transforming a distillation column with a controlled freezing zone from start-up conditions to after start-up operating conditions comprising the steps of:

• feeding at least one acid gas containing methane to a lower distillation zone;
• producing in said lower distillation zone an enriched carbon dioxide liquid bottoms stream and a freezing zone vapor feedstream at a temperature and pressure at which substantially no carbon dioxide solids are formed;
• contacting said freezing zone vapor feedstream with at least one freezing zone liquid feedstream containing methane in a controlled freezing zone at a temperature and pressure wherein both solids containing carbon dioxide and a methane-enriched vapor stream are formed;
• stripping the acid gas component from the methane-enriched vapor stream to produce an acid gas stripped stream;
• separating said stripped stream into liquid and vapor components;
• refluxing the liquid component of said stripped stream to the distillation column;
• continuing the reflux of the distillation column until operating temperature has been achieved;
• redirecting the methane-enriched vapor stream from the stripping means to a separating means;
• separating the methane-enriched vapor stream into vapor and liquid components;
• and
• refluxing the liquid component of the methane-enriched vapor stream to the distillation column.

A method for start-up of a distillation column with a controlled freezing zone comprising the steps:

• feeding a mixture of at least one acid gas and methane to a lower distillation zone;
• producing in said lower distillation zone an enriched carbon dioxide liquid bottoms stream and a freezing zone vapor feedstream at a temperature and pressure at which substantially no carbon dioxide solids are formed;
• contacting said freezing zone vapor feedstream with at least one freezing zone liquid feedstream containing methane in a controlled freezing zone at a temperature and pressure wherein both solids containing carbon dioxide and a methane-enriched vapor stream are formed;
• contacting said methane-enriched vapor stream with a methane-enriched liquid stream in an upper distillation zone operated at a temperature and pressure at which substantially no carbon dioxide solids are produced to form an upper distillation zone overhead stream and an upper distillation zone bottoms stream;
• stripping the acid gas component from the upper distillation zone overhead stream to produce an acid gas stripped stream;
• separating said stripped stream into liquid and vapor components;
• and
• refluxing the liquid component of said stripped stream to the distillation column.

A method for separating a feedstream containing at least one acid gas from methane comprising the steps of:

• feeding at least one acid gas containing methane to a lower distillation zone of a distillation column;
• producing in said lower distillation zone an enriched carbon dioxide liquid bottoms stream and a freezing zone vapor feedstream at a temperature and pressure at which substantially no carbon dioxide solids are formed;
• contacting said freezing zone vapor feedstream with at least one freezing zone liquid feedstream containing methane in a controlled freezing zone at a temperature and pressure wherein both solids containing carbon dioxide and a methane-enriched vapor stream are formed;
• contacting said methane-enriched vapor stream with a methane-enriched liquid stream in an upper distillation zone operated at a temperature and pressure at which substantially no carbon dioxide solids are produced to form an upper distillation zone bottoms stream;
• separating said overhead stream into liquid and vapor components;
• refluxing the liquid component of the upper distillation zone overhead stream to the column;
• and
• stripping the remaining acid components from the vapor component of the upper distillation zone overhead stream.

A method of transforming a distillation column with a controlled freezing zone from start-up conditions to after start-up operating conditions comprising the steps of:

• feeding at least one acid gas containing methane to a lower distillation zone;
• producing in said lower distillation zone an enriched carbon dioxide liquid bottoms stream and a freezing zone vapor feedstream at a temperature and pressure at which substantially no carbon dioxide solids are formed;
• contacting said freezing zone vapor feedstream with at least one freezing zone liquid feedstream containing methane in a controlled freezing zone at a temperature and pressure wherein both solids containing carbon dioxide and a methane-enriched vapor stream are formed;
• contacting said methane-enriched vapor stream with a methane-enriched liquid stream in an upper distillation zone operated at a temperature and pressure at which substantially no carbon dioxide solids are produced to form an upper distillation zone overhead stream and an upper distillation zone bottoms stream;
• stripping the acid gas components from the upper distillation zone overhead stream to produce an acid gas stripped stream;
• separating said stripped stream into liquid and vapor components;
• refluxing the liquid component of said stripped stream to the distillation column;
• continuing the reflux of the distillation column until operating temperature has been achieved;
• redirecting the upper distillation zone overhead stream from the stripping means to a separating means;
• separating the upper distillation zone overhead stream into vapor and liquid components;
• stripping the remaining acid gas components from the vapor component of the overhead stream;
• and
• refluxing the liquid component of the overhead stream to the tower.

A method of transforming a distillation column with a controlled freezing zone from start-up conditions to after start-up operating conditions comprising the steps of:

• feeding at least one acid gas containing methane to a lower distillation zone;
• producing in said lower distillation zone an enriched carbon dioxide liquid bottoms stream and a freezing zone vapor feedstream at a temperature and pressure at which substantially no carbon dioxide solids are formed;
• contacting said freezing zone vapor feedstream with at least one freezing zone liquid feedstream containing methane in a controlled freezing zone at a temperature and pressure wherein both solids containing carbon dioxide and a methane-enriched vapor stream are formed;
• contacting said methane-enriched vapor stream with a methane-enriched liquid stream in an upper distillation zone operated at a temperature and pressure at which substantially no carbon dioxide solids are produced to form an upper distillation zone overhead stream and an upper distillation zone bottoms stream;
• stripping the acid gas components from the upper distillation zone overhead stream to produce an acid gas stripped stream;
• separating said stripped stream into liquid and vapor components;
• refluxing the liquid component of said stripped stream to the distillation column;
• continuing the reflux of the distillation column until operating temperature has been achieved;
• redirecting the upper distillation zone overhead stream from the stripping means to a separating means;
• separating the upper distillation zone overhead stream into vapor and liquid components;
• refluxing the liquid component of the overhead stream to the tower.

An apparatus for start-up of a distillation column with a controlled freezing zone comprising:

• a distillation column with a lower distillation zone and a controlled freezing zone;
• an inlet to said lower zone of the distillation column for a feedstream comprising at least one acid gas and methane;
• said lower distillation zone wherein an enriched carbon dioxide liquid bottoms stream and a freezing zone vapor feedstream are produced at a temperature and pressure at which substantially no carbon dioxide solids are formed;
• said controlled freezing zone adjacent to said lower distillation zone with a controlled stream temperature and pressure wherein both a solids containing carbon dioxide and a methane-enriched vapor stream are formed;
• a means for stripping the acid gas components from the methane-enriched vapor stream to produce an acid gas stripped stream;
• a means for separating said stripped stream into liquid and vapor components;
• and
• a means for refluxing the liquid component of said stripped stream to the distillation column.

An apparatus for separating a feedstream containing at least one acid gas from methane comprising:

• a distillation column comprised of a lower distillation zone and a controlled freezing zone;
• an inlet to said lower zone of the distillation column for a feedstream comprising at least one acid gas containing methane;
• said lower distillation zone of said distillation column operated at a temperature and pressure at which substantially no carbon dioxide solids are formed to produce an enriched carbon dioxide liquid bottoms stream and a freezing zone vapor feedstream;
• said controlled freezing zone wherein a freezing zone liquid feedstream containing methane is contacted with said freezing zone vapor feedstream at a temperature and pressure wherein both solids containing carbon dioxide and a methane-enriched vapor stream are formed;
• a means for separating said methane-enriched vapor stream into liquid and vapor components;
• a means for refluxing the liquid component of the methane-enriched vapor stream to the column;
• and
• a means for stripping the remaining acid components from the vapor component of the methane-enriched vapor stream.

An apparatus for transforming a distillation column with a controlled freezing zone from start-up conditions to after start-up operating conditions comprising:

• a distillation column with a lower distillation zone and a controlled freezing zone;
• an inlet to said lower zone of the distillation column for a feedstream comprising at least one acid gas containing methane;
• said lower distillation zone wherein an enriched carbon dioxide liquid bottoms stream and a freezing zone vapor feedstream are produced at a temperature and pressure at which substantially no carbon dioxide solids are formed;
• said controlled freezing zone wherein a freezing zone liquid feedstream containing methane is contacted with said freezing zone vapor feedstream at a temperature and pressure wherein both solids containing carbon dioxide and a methane-enriched vapor stream are formed;
• a first means for stripping the acid gas components from the methane-enriched vapor stream to produce an acid gas stripped stream;
• a means for separating said stripped stream into liquid and vapor components;
• a means for refluxing the liquid component of said stripped stream to the distillation column;
• a means for redirecting the methane-enriched vapor stream from the first means for stripping to a second means for separating where the methane-enriched vapor may be separated into vapor and liquid components;
• a second means for stripping the remaining acid gas components from the vapor component of the methane-enriched vapor stream;
• and
• a means for refluxing the liquid component of the methane-enriched vapor stream to the tower.

An apparatus for transforming a distillation column with a controlled freezing zone from start-up conditions to after start-up operating conditions comprising:

• a distillation column with a lower distillation zone and a controlled freezing zone;
• an inlet to said lower zone of the distillation column for a feedstream comprising at least one acid gas containing methane;
• said lower distillation zone wherein an enriched carbon dioxide liquid bottoms stream and a freezing zone vapor feedstream are produced at a temperature and pressure at which substantially no carbon dioxide solids are formed;
• said controlled freezing zone wherein a freezing zone liquid feedstream containing methane is contacted with said freezing zone vapor feedstream at a temperature and pressure wherein both solids containing carbon dioxide and a methane-enriched vapor stream are formed;
• a first means for stripping the acid gas components from the methane-enriched vapor stream to produce an acid gas stripped stream;
• a means for separating said stripped stream into liquid and vapor components;
• a means for refluxing the liquid component of said stripped stream to the distillation column;
• a means for redirecting the methane-enriched vapor stream from the first means for stripping to a second means for separating where the methane-enriched vapor may be separated into vapor and liquid components;
• and
• a means for refluxing the liquid component of the methane-enriched vapor stream to the tower.