Removal of water from bio-oil
View Patent ↗A process and system for separating water from bio-oil by using a partial condenser. The process comprises partially condensing vapor conversion products from a biomass conversion reaction to produce a water-rich overhead stream and a water-depleted stream comprising condensed bio-oil. The partial condenser removes a substantial portion of the water from the bio-oil, while providing an effective and flexible process for producing bio-oil.
1. A process for producing bio-oil, said process comprising:
(a) thermochemically converting biomass in a conversion reactor to thereby produce a conversion effluent comprising vapor conversion products;
(b) partially condensing at least a portion of said vapor conversion products in a partial condenser to thereby produce a first water-rich overhead stream comprising noncondensable gases, water, and light organic compounds and a first water-depleted stream comprising condensed bio-oil, wherein said partial condenser operates at a bottom temperature of at least 115° C.;
(c) separating at least a portion of said first water-rich overhead stream in a separator to thereby produce a second water-rich stream comprising water and water-soluble light organic compounds and a second water-depleted stream comprising water-insoluble light organic compounds; and
(d) introducing a reflux stream into said partial condenser, wherein said reflux stream comprises at least a portion of said first water-depleted stream and/or at least a portion of said second water-depleted stream.
2. The process of claim 1 wherein said reflux stream provides at least a portion of the cooling required to partially condense said vapor conversion products in said partial condenser.
3. The process of claim 1 wherein said reflux stream comprises at least a portion of said second water-depleted stream.
4. The process of claim 1 wherein said water-soluble light organic compounds comprise carboxylic acids, methyl vinyl ketones, and/or cyclopentenones, wherein said water-insoluble light organic compounds comprise benzene, toluene, and/or xylene.
5. The process of claim 1 wherein said first water-rich stream is rich in carboxylic acids, wherein said first water-depleted stream is depleted in carboxylic acids.
6. The process of claim 1 wherein said second water-rich stream is rich in said water-soluble light organic compounds, wherein said second water-depleted stream is rich in said water-insoluble light organic compounds.
7. The process of claim 1 wherein said first water-depleted stream further comprises a concentrated aqueous phase comprising water and water-soluble heavy organic compounds, further comprising removing at least a portion of said concentrated aqueous phase from said first water-depleted stream.
8. The process of claim 7 further comprising routing at least a portion of the removed concentrated aqueous phase to said conversion reactor and/or to a combustor for use as a heat source.
9. The process of claim 1 wherein said separating of step (c) includes removing said second water-rich stream and said second water-depleted streams from said separator as separate liquid streams.
10. The process of claim 9 wherein said separating of step (c) includes removing a noncondensable gas stream from said separator as a separate stream from said water-rich and water-depleted streams.
11. The process of claim 10 further comprising routing at least a portion of the removed noncondensable gas stream to said conversion reactor for use as at least a portion of a lift gas in said conversion reactor.
12. The process of claim 1 further comprising fractionating at least a portion of said second water-rich stream in a fractionator to thereby produce a third water-rich stream and a third water-depleted stream, wherein said third water-depleted stream is rich in water-soluble light organic compounds.
13. The process of claim 1 wherein said thermochemically converting of step (a) comprises fast pyrolysis.
14. A process for producing bio-oil, said process comprising:
(a) thermochemically converting biomass in a conversion reactor to thereby produce a conversion effluent comprising vapor conversion products;
(b) partially condensing at least a portion of said vapor conversion products in a partial condenser to thereby produce a first water-rich overhead stream comprising noncondensable gases, water, and light organic compounds and a first water-depleted stream comprising condensed bio-oil, wherein said partial condenser operates at a bottom temperature of at least 115° C.;
(c) separating at least a portion of said first water-rich overhead stream in a separator to thereby produce a second water-rich stream comprising water and water-soluble light organic compounds and a second water-depleted stream comprising water-insoluble light organic compounds; and
(d) fractionating at least a portion of said second water-rich stream in a fractionator to thereby produce a third water-rich stream comprising water and a third water-depleted stream comprising water-soluble light organic compounds.
15. The process of claim 14 further comprising introducing a reflux stream into said partial condenser, wherein said reflux stream provides at least a portion of the cooling required to partially condense said vapor conversion products in said partial condenser, wherein said reflux stream comprises at least a portion of said second water-depleted stream.
16. The process of claim 14 wherein said water-soluble light organic compounds comprise carboxylic acids, methyl vinyl ketones, and/or cyclopentenones, wherein said water-insoluble light organic compounds comprise benzene, toluene, and/or xylene, wherein said first water-rich stream is rich in carboxylic acids, wherein said first water-depleted stream is depleted in carboxylic acids, wherein said second water-rich stream is rich in said water-soluble light organic compounds, wherein said second water-depleted stream is rich in said water-insoluble light organic compounds.
17. The process of claim 14 wherein said separating of step (c) includes removing said second water-rich stream and said second water-depleted streams from said separator as separate liquid streams.
18. The process of claim 17 wherein said separating of step (c) includes removing a noncondensable gas stream from said separator as a separate stream from said water-rich and water-depleted streams.
19. A system for producing bio-oil, said system comprising:
a biomass feedstock source for providing solid particulate biomass;
a conversion reactor for thermally converting at least a portion of said solid particulate biomass feedstock into condensable vapor conversion products;
a partial condenser for partially condensing at least a portion of said condensable vapor conversion products into a first water-rich overhead stream and a first water-depleted stream comprising condensed bio-oil, wherein said partial condenser comprises a reflux inlet, wherein said partial condenser is configured to operate at a bottom temperature of at least 115° C.;
a condenser for condensing at least a portion of said first water-rich overhead stream to thereby produce a second water-depleted stream and second water-rich stream;
a reflux system for routing at least a portion of said second water-depleted stream to said reflux inlet of said partial condenser; and
a fractionator for separating at least a portion of said second water-rich stream to thereby produce a third water-rich stream and a third water-depleted stream.
20. The system of claim 19 further comprising a phase separator for separating at least a portion of said first water-depleted stream into a bio-oil stream and a concentrated aqueous stream.