The present invention relates to a process for removing carbon dioxide from a synthesis gas having at least hydrogen and carbon dioxide in which the synthesis gas is at least partially freed of carbon dioxide in an absorption apparatus by physical absorption at elevated absorption pressure. The carbon dioxide is subsequently desorbed by pressure reduction relative to the absorption pressure in a plurality of serially arranged flash stages and an at least partially regenerated absorption medium is withdrawn from the last of the plurality of serially arranged flash stages, recompressed to absorption pressure and recycled into the absorption apparatus for use as absorption medium. It is also provided according to the invention that a partially regenerated absorption medium from a flash stage upstream of the last of the plurality of serially arranged flash stages is recompressed to absorption pressure and recycled into the absorption apparatus for use as absorption medium.

The present invention relates to a process for removing carbon dioxide from a synthesis gas having at least hydrogen and carbon dioxide in which the synthesis gas is at least partially freed of carbon dioxide in an absorption apparatus by physical absorption at elevated absorption pressure. The carbon dioxide is subsequently desorbed by pressure reduction relative to the absorption pressure in a plurality of serially arranged flash stages and an at least partially regenerated absorption medium is withdrawn from the last of the plurality of serially arranged flash stages, recompressed to absorption pressure and recycled into the absorption apparatus for use as absorption medium. It is also provided according to the invention that a partially regenerated absorption medium from a flash stage upstream of the last of the plurality of serially arranged flash stages is recompressed to absorption pressure and recycled into the absorption apparatus for use as absorption medium.

Fuel and fuel additives can be produced by processes that provide Fischer-Tropsch liquids having high biogenic carbon concentrations of up to about 100% biogenic carbon. The fuels and fuel additive have essentially the same high biogenic concentration as the Fischer-Tropsch liquids which, in turn, contain the same concentration of biogenic carbon as the feedstock.

Fuel and fuel additives can be produced by processes that provide Fischer-Tropsch liquids having high biogenic carbon concentrations of up to about 100% biogenic carbon. The fuels and fuel additive have essentially the same high biogenic concentration as the Fischer-Tropsch liquids which, in turn, contain the same concentration of biogenic carbon as the feedstock.

The present invention concerns a process for the separation of a gas mixture containing CO.sub.2 and at least one inert gaseous species, comprising (a) feeding the gas mixture into an adsorption column via a first inlet located at a first side of the column, wherein the adsorption column contains a solid CO.sub.2 sorbent loaded with H.sub.2O molecules and thereby desorbing H.sub.2O molecules and adsorbing CO.sub.2 molecules, to obtain a sorbent loaded with CO.sub.2 and an inert product stream; and then (b) feeding a stripping gas comprising H.sub.2O into the adsorption column via a second inlet located at a second side which is opposite to the first inlet, thereby stripping the sorbent and desorbing CO.sub.2 molecules and adsorbing H.sub.2O molecules, to obtain a sorbent loaded with H.sub.2O and the CO.sub.2 product stream, wherein the adsorption column is re-used in step (a) after being stripped in step (b). The invention also concerns an apparatus for performing the process according to the invention.

Processes for producing high biogenic concentration Fischer-Tropsch liquids derived from the organic fraction of municipal solid wastes (MSW) feedstock that contains a relatively high concentration of biogenic carbon (derived from plants) and a relatively low concentration of non-biogenic carbon (derived from fossil sources) wherein the biogenic content of the Fischer-Tropsch liquids is the same as the biogenic content of the feedstock.

Processes for producing high biogenic concentration Fischer-Tropsch liquids derived from the organic fraction of municipal solid wastes (MSW) feedstock that contains a relatively high concentration of biogenic carbon (derived from plants) and a relatively low concentration of non-biogenic carbon (derived from fossil sources) wherein the biogenic content of the Fischer-Tropsch liquids is the same as the biogenic content of the feedstock.

The present invention provides a process for the manufacture of a useful product from carbonaceous feedstock of fluctuating compositional characteristics, the process comprising the steps of: continuously providing the carbonaceous feedstock of fluctuating compositional characteristics to a gasification zone; gasifying the carbonaceous feedstock in the gasification zone to obtain raw synthesis gas; recovering at least part of the raw synthesis gas from the gasification zone and supplying at least part of the recovered raw synthesis gas to a partial oxidation zone; equilibrating the H.sub.2:CO ratio of the raw synthesis gas in the partial oxidation zone to obtain equilibrated synthesis gas; recovering at least part of the equilibrated synthesis gas from the partial oxidation zone and treating the gas to remove impurities and generate a fine synthesis gas; optionally adjusting the H.sub.2:CO ratio of at least part of the fine synthesis gas to obtain adjusted fine synthesis gas; and converting the optionally adjusted fine synthesis gas into the useful product in a further chemical reaction requiring a usage ratio; wherein the fine synthesis gas H2:CO ratio is below the usage ratio and wherein any optional adjustment of at least part of the fine synthesis gas H.sub.2:CO ratio is effective to increase the H.sub.2:CO ratio in the fine synthesis gas to a level at, nearer to or above the usage ratio; wherein the H.sub.2:CO ratio of the raw synthesis gas fluctuates during operation of the process as a result of the fluctuating compositional characteristics of the carbonaceous feedstock by a percentage of ±x; and the H.sub.2:CO ratio of the equilibrated synthesis gas does not fluctuate during operation of the process or fluctuates during operation of the process as a result of the fluctuating compositional characteristics of the carbonaceous feedstock by a percentage±y, y being a lower percentage than x.

The present invention provides a process for the manufacture of a useful product from carbonaceous feedstock of fluctuating compositional characteristics, the process comprising the steps of: continuously providing the carbonaceous feedstock of fluctuating compositional characteristics to a gasification zone; gasifying the carbonaceous feedstock in the gasification zone to obtain raw synthesis gas; recovering at least part of the raw synthesis gas from the gasification zone and supplying at least part of the recovered raw synthesis gas to a partial oxidation zone; equilibrating the H.sub.2:CO ratio of the raw synthesis gas in the partial oxidation zone to obtain equilibrated synthesis gas; recovering at least part of the equilibrated synthesis gas from the partial oxidation zone and treating the gas to remove impurities and generate a fine synthesis gas; optionally adjusting the H.sub.2:CO ratio of at least part of the fine synthesis gas to obtain adjusted fine synthesis gas; and converting the optionally adjusted fine synthesis gas into the useful product in a further chemical reaction requiring a usage ratio; wherein the fine synthesis gas H2:CO ratio is below the usage ratio and wherein any optional adjustment of at least part of the fine synthesis gas H.sub.2:CO ratio is effective to increase the H.sub.2:CO ratio in the fine synthesis gas to a level at, nearer to or above the usage ratio; wherein the H.sub.2:CO ratio of the raw synthesis gas fluctuates during operation of the process as a result of the fluctuating compositional characteristics of the carbonaceous feedstock by a percentage of ±x; and the H.sub.2:CO ratio of the equilibrated synthesis gas does not fluctuate during operation of the process or fluctuates during operation of the process as a result of the fluctuating compositional characteristics of the carbonaceous feedstock by a percentage±y, y being a lower percentage than x.

The present invention provides a process for the manufacture of a synthetic fuel comprising gasifying a carbonaceous feedstock comprising waste materials and/or biomass to generate a raw synthesis gas; supplying the raw synthesis gas to a primary clean-up zone to wash particulates and ammonia or HCl out of the raw synthesis gas; contacting the synthesis gas in a secondary clean-up zone with a physical solvent for sulphurous materials; contacting the desulphurised raw synthesis gas in a tertiary clean-up zone with a physical solvent for CO.sub.2 effective to absorb CO.sub.2; removing at least part of the absorbed CO.sub.2 in a solvent regeneration stage to recover CO.sub.2 in a form sufficiently pure for sequestration or other use; and supplying the clean synthesis gas to a further reaction train to generate a synthetic fuel.