Simplified LNG process
First Claim
1. A method for production of liquefied natural gas (LNG) comprising:
- taking a supply stream of natural gas including contaminants including water vapor, CO2 and H2S, and by-products including light overhead gases and heavier hydrocarbons including Ethane, Propane and any other heavy components;
in a compression step, compressing said supply gas stream;
in an extracting step, extracting from the supply gas stream said water vapor, H2S and CO2 of said contaminants;
in a cooling step, cooling the entire supply gas stream excluding the contaminants extracted in said extracting step and forming a dense phase stream which is arranged to produce a two phase liquid/vapor stream on subsequent expansion;
downstream of the compressing, extracting and cooling steps in an expanding step expanding the entire compressed, cooled, dense phase, supply gas stream to form an expanded stream which is a two phase liquid/vapor stream;
at a first separation step subsequent to the expanding step, separating the expanded stream into a first stream and a second stream;
wherein the first stream contains Ethane, Propane and heavy components together with some methane;
wherein the second stream contains some methane and most of said light overhead gases;
further expanding the first stream and supplying the further expanded first stream to a second separation step comprising a fractionator or separator;
in the fractionator or separator in the second separation step, separating the first stream into an overhead vapor stream and a bottom stream;
wherein the bottom stream contains some methane and most of the said Ethane, Propane and any other heavy components;
wherein the overhead vapor stream is a cold energy supply gas stream consisting mainly of methane arranged to be sufficiently pure by having sufficient of the H2O, CO2 and H2S contaminants, and light overhead gases and heavier hydrocarbons, removed to meet a product specification for the composition of an LNG supply;
providing a commercial supply as LNG from the overhead vapor stream;
said bottom stream being removed for use separate from said commercial supply;
wherein the second stream is not supplied to the fractionator or separator in said second separation step but is instead used as a coolant in upstream heat exchangers acting on said supply gas stream after said extracting step and is removed for use separate from said commercial supply.
3 Assignments
0 Petitions
Accused Products
Abstract
A simplified method for production of a commercial supply liquefied natural gas (LNG) supplied in a pressurized vessel includes taking a supply of natural gas including contaminants from a stranded well or from a pipe line and extracting from the supply gas water vapor and CO2 in a fixed bed absorption system. In a first stage the supply gas is separated into first and second streams where the first stream contains all the cold energy available from the feed stream and sufficient of the contaminants are removed to meet a product specification for the composition of the LNG supply. In a second stage the first stream is liquefied by the available cool energy for commercial pressurized supply container The second stream contains natural gas which is as much as 75% of the feed stream together with substantially all the contaminants and is used as a natural gas supply.
17 Citations
13 Claims
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1. A method for production of liquefied natural gas (LNG) comprising:
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taking a supply stream of natural gas including contaminants including water vapor, CO2 and H2S, and by-products including light overhead gases and heavier hydrocarbons including Ethane, Propane and any other heavy components; in a compression step, compressing said supply gas stream; in an extracting step, extracting from the supply gas stream said water vapor, H2S and CO2 of said contaminants; in a cooling step, cooling the entire supply gas stream excluding the contaminants extracted in said extracting step and forming a dense phase stream which is arranged to produce a two phase liquid/vapor stream on subsequent expansion; downstream of the compressing, extracting and cooling steps in an expanding step expanding the entire compressed, cooled, dense phase, supply gas stream to form an expanded stream which is a two phase liquid/vapor stream; at a first separation step subsequent to the expanding step, separating the expanded stream into a first stream and a second stream; wherein the first stream contains Ethane, Propane and heavy components together with some methane; wherein the second stream contains some methane and most of said light overhead gases; further expanding the first stream and supplying the further expanded first stream to a second separation step comprising a fractionator or separator; in the fractionator or separator in the second separation step, separating the first stream into an overhead vapor stream and a bottom stream; wherein the bottom stream contains some methane and most of the said Ethane, Propane and any other heavy components; wherein the overhead vapor stream is a cold energy supply gas stream consisting mainly of methane arranged to be sufficiently pure by having sufficient of the H2O, CO2 and H2S contaminants, and light overhead gases and heavier hydrocarbons, removed to meet a product specification for the composition of an LNG supply; providing a commercial supply as LNG from the overhead vapor stream; said bottom stream being removed for use separate from said commercial supply; wherein the second stream is not supplied to the fractionator or separator in said second separation step but is instead used as a coolant in upstream heat exchangers acting on said supply gas stream after said extracting step and is removed for use separate from said commercial supply. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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Specification