Process for the production of glycols from a saccharide-containing feedstock
The invention provides a process for the continuous production of one or more glycols from a saccharide-containing feedstock, said process comprising the steps of: i) contacting the saccharide-containing feedstock with hydrogen in the presence of one or more catalysts in a reactor at a reaction temperature and a reaction pressure in a continuous manner, to provide a reaction effluent stream comprising hydrogen and one or more glycols; ii) separating hydrogen from the reaction effluent stream, without substantial de-pressurization of said reaction effluent stream to provide a separated hydrogen stream and a liquid effluent stream; and iii) providing at least a portion of the separated hydrogen stream as a hydrogen recycle stream to the reactor for re-use in step i).
1. A process for the continuous production of one or more glycols from a saccharide-containing feedstock, said process comprising the steps of:
i) contacting the saccharide-containing feedstock with hydrogen in the presence of one or more catalysts in a reactor at a reaction temperature and a reaction pressure in a continuous manner, to provide a reaction effluent stream comprising hydrogen and one or more glycols;
ii) separating hydrogen from the reaction effluent stream, to provide a separated hydrogen stream and a first liquid effluent stream, wherein the hydrogen is separated from the reaction effluent stream at a pressure within 0.2 MPa of the reaction pressure;
iii) providing at least a portion of the separated hydrogen stream as a hydrogen recycle stream to the reactor for re-use in step i); and
iv) cooling the first liquid effluent stream to provide a second effluent stream and a first vapour stream, wherein the first vapour stream provides heat to the process; wherein the reaction temperature is in the range of from at least 130° C. to at most 300° C. and the reaction pressure is in the range of from at least 1 MPa to at most 16 MPa.
2. The process according to claim 1 , wherein the saccharide-containing feedstock comprises at least 1 wt % saccharide in a solvent.
3. The process according to claim 2 , wherein the solvent is water.
4. The process according to claim 1 , wherein the saccharide-containing feedstock comprises oligosaccharides and/or polysaccharides and is subjected to a pre-treatment step before being fed to the reactor.
5. The process according to claim 1 , wherein the saccharide-containing feedstock fed to the reactor comprises one or more saccharides selected from the group consisting of glucose, sucrose and starch.
6. The process according to claim 1 , wherein the hydrogen is separated from the reaction effluent stream at a pressure within 0.1 MPa of the reaction pressure.
7. The process according to claim 1 , wherein cooling the first liquid effluent stream is by staged flashing.
8. The process according to claim 2 , wherein cooling the first liquid effluent stream is by multistage evaporation of the solvent.
9. The process according to claim 1 , wherein the hydrogen is separated from the reaction effluent stream at a temperature within 20° C. of the reaction temperature.