Production of liquid hydrocarbon products
AssigneeSasol Technology (Proprietary) Limited
InventorsAndre Steynberg, Simon Charles Clarke
Life of this patent
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Abstract
A process for producing liquid hydrocarbon products includes converting a natural gas feedstock to synthesis gas, which is reacted, in a hydrocarbon synthesis stage and by a Fischer-Tropsch reaction, to produce a range of hydrocarbon product. An overheads vapour phase is separated from a liquid phase, and fed to a product condensation stage, where condensation of some components thereof takes place. A vapour phase, an aqueous phase, and a condensed product phase are withdrawn. The vapour phase is fed to a vapour phase work-up stage where a gas component comprising increased concentrations of CO and H2, relative to the vapour phase feed to the vapour phase work-up stage, is recovered, with this gas component being recycled to the hydrocarbon synthesis stage.
Claims13
A process for producing liquid hydrocarbon products, which process includes
- converting, in a synthesis gas production stage, a natural gas feedstock comprising mainly CH4 to synthesis gas comprising CO, H2, CO2 and CH4;
- feeding the synthesis gas, as a feedstock, to a hydrocarbon synthesis stage;
- in the hydrocarbon synthesis stage, reacting the synthesis gas at elevated temperature and pressure, and in the presence of a Fischer-Tropsch catalyst, to produce a range of hydrocarbon products of differing carbon chain lengths, and separating an overheads vapour phase comprising gaseous hydrocarbon products, unreacted synthesis gas, water, and any soluble organic compounds which form in the hydrocarbon synthesis stage, from a liquid phase comprising heavier liquid hydrocarbon products;
- withdrawing the liquid phase from the hydrocarbon synthesis stage;
- withdrawing the overheads vapour phase from the hydrocarbon synthesis stage and feeding it to a product condensation stage, where condensation of at least some components of the overheads vapour phase takes place;
- withdrawing from the product condensation stage a vapour phase comprising gaseous hydrocarbon products, an aqueous phase comprising water and said any soluble organic compounds which form in the hydrocarbon synthesis stage, and a condensed product phase comprising condensed hydrocarbon products;
- feeding the vapour phase to a vapour phase work-up stage;
- in the vapour phase work-up stage, recovering from the vapour phase a first gas component comprising increased concentrations of CO and H2, relative to the vapour phase feed to the vapour phase work-up stage;
- and
- recycling the CO and H2-containing first gas component to the hydrocarbon synthesis stage, as a feedstock component.
A process for producing liquid hydrocarbon products, which process includes
- converting, in a synthesis gas production stage, a natural gas feedstock comprising mainly CH4 to synthesis gas comprising CO, H2, CO2 and CH4;
- without removal of CO2, feeding the synthesis gas, as a feedstock, to a hydrocarbon synthesis stage;
- in the hydrocarbon synthesis stage, reacting the synthesis gas at elevated temperature and pressure, and in the presence of a Co-based Fischer-Tropsch catalyst, to produce a range of hydrocarbon products of differing carbon chain lengths, and separating an overheads vapour phase comprising gaseous hydrocarbon products, unreacted synthesis gas, water, and any soluble organic compounds which form in the hydrocarbon synthesis stage, from a liquid phase comprising heavier liquid hydrocarbon products;
- withdrawing the liquid phase from the hydrocarbon synthesis stage;
- withdrawing the overheads vapour phase from the hydrocarbon synthesis stage and feeding it to a product condensation stage, where condensation of at least some components of the vapour phase takes place;
- withdrawing from the product condensation stage a vapour phase comprising gaseous hydrocarbon products, an aqueous phase comprising water and said any soluble organic compounds which form in the hydrocarbon synthesis stage, and a condensed product phase comprising condensed hydrocarbon products;
- feeding the vapour phase to a heavy ends recovery stage;
- in the heavy ends recovery stage, separating hydrocarbon products having 3 or more carbon atoms, from the vapour phase;
- and
- recycling at least a portion of the vapour phase from the heavy ends recovery stage to the synthesis gas production stage, as a feedstock component.
Dependencies are inferred from the claim text.