Processes for washing a spent ion exchange bed and for treating biomass-derived pyrolysis oil, and apparatuses for treating biomass-derived pyrolysis oil
Processes and apparatuses for washing a spent ion exchange bed and for treating biomass-derived pyrolysis oil are provided herein. An exemplary process for washing a spent ion exchange bed employed in purification of biomass-derived pyrolysis oil includes the step of providing a ion-depleted pyrolysis oil stream having an original oxygen content. The ion-depleted pyrolysis oil stream is partially hydrotreated to reduce the oxygen content thereof, thereby producing a partially hydrotreated pyrolysis oil stream having a residual oxygen content that is less than the original oxygen content. At least a portion of the partially hydrotreated pyrolysis oil stream is passed through the spent ion exchange bed. Water is passed through the spent ion exchange bed after passing at least the portion of the partially hydrotreated pyrolysis oil stream therethrough.
1. A process for treating biomass-derived pyrolysis oil comprising a metal ion component and having an original oxygen content, said process comprising the steps of:
pyrolyzing a biomass feed in a pyrolysis reactor to form a biomass-derived pyrolysis vapor stream;
condensing at least a portion of the biomass-derived pyrolysis vapor stream in a condensing system to form a biomass-derived pyrolysis oil stream;
passing the biomass-derived pyrolysis oil stream through an ion exchange bed to form an ion-depleted pyrolysis oil stream;
partially hydrotreating the ion-depleted pyrolysis oil stream in a hydrotreating device to reduce the oxygen content thereof, thereby producing a partially hydrotreated pyrolysis oil stream having a residual oxygen content that is less than the original oxygen content;
passing at least a portion of the partially hydrotreated pyrolysis oil stream through the spent ion exchange bed; and
passing water through the spent ion exchange bed after passing at least the portion of the partially hydrotreated pyrolysis oil stream therethrough.
2. The process of claim 1 , further comprising the step of splitting the partially hydrotreated pyrolysis oil stream into at least a recycle stream and a flushing stream, and wherein the step of passing at least the portion of the partially hydrotreated pyrolysis oil stream through the spent ion exchange bed is further defined as passing the flushing stream through the spent ion exchange bed.
3. The process of claim 2 , wherein the recycle stream is combined with the ion-depleted pyrolysis oil stream prior to partially hydrotreating the ion-depleted pyrolysis oil stream.
4. The process of claim 2 , wherein the partially hydrotreated pyrolysis oil stream is further split into a product stream.
5. The process of claim 4 , wherein the product stream is additionally hydrotreated in at least one additional hydrotreating device to further reduce the oxygen content thereof.
6. The process of claim 4 , wherein the product stream is split from the partially hydrotreated pyrolysis oil stream prior to splitting the partially hydrotreated pyrolysis oil stream into the recycle stream and the flushing stream.
7. The process of claim 1 , wherein the step of passing at least the portion of the partially hydrotreated pyrolysis oil stream through the ion exchange bed produces a flushed pyrolysis oil stream, and wherein the flushed pyrolysis oil stream is mixed with the ion-depleted pyrolysis oil stream prior to the step of partially hydrotreating the ion-depleted pyrolysis oil stream.
8. The process of claim 1 , wherein the ion exchange bed is in fluid communication with the hydrotreating device and wherein the ion-depleted pyrolysis oil stream is passed from the ion exchange bed to the hydrotreating device.
9. The process of claim 1 , further comprising the step of separating a solids/aqueous component from the partially hydrotreated pyrolysis oil stream.
10. The process of claim 9 , further comprising the step of cooling the partially hydrotreated pyrolysis oil stream prior to the step of separating the solids/aqueous component from the partially hydrotreated pyrolysis oil stream.