|Overview of project area. Click to enlarge.|
Chemrec’s pulp mill-integrated BioDME (dimethyl ether) biorefinery demonstration plant project will break ground in September in Piteå, Sweden, with expected biofuel production by mid-2010. The project will demonstrate the production of BioDME for use as a renewable fuel in diesel engines from forest biomass over the black liquor route and will also demonstrate the use of this fuel in heavy vehicles in commercial service.
The Chemrec gasification process in the BioDME demonstration plant will combine two objectives: production of green liquor from black liquor and upgrade of the organic part of the black liquor to synthesis gas. Primary gas cleaning and cooling also takes place here, using the Chemrec DP-1 gasifier plant for this service.
Carbon conversion and sulfate reduction in this process is near 100%. Syngas tar and methane content is very low, eliminating in biomass gasification the common need for secondary tar and methane reforming.
Another advantage of this process over conventional DME processes is the flexible distillation system, according to Chemrec. The separation process in the BioDME pilot contains more separation columns than the commercially available DME separation schemes. This feature comes at a cost but also gives DME with a higher purity and allows the co-production of methanol if desired.
The gas treatment step of the plant rejects carbon dioxide at high concentration. The process is therefore also very suitable to combine with carbon capture and sequestration (CCS). Using renewable feedstock, the produced biofuel will have a carbon footprint of less than zero.
In June, Chemrec announced that its DP-1 black liquor gasification development plant, also in Piteå, had reached 10,000 accumulated operating hours. (Earlier post.) This plant is the only gasification plant producing high-quality synthesis gas from which DME and other biofuels can be produced based totally on renewable woody biomass feedstock.
The primary use of DME today is as a liquefied petroleum gas (LPG) substitute, yet DME use as an advanced diesel fuel is also being developed. With a high cetane number and with no particle formation during combustion, DME provides the opportunity to very cost-efficiently meet stringent exhaust emission targets, according to Chemrec CEO Richard J. LeBlanc.
BioDME offers a very high reduction of fossil carbon dioxide emissions—around 95%—compared to conventional diesel fuel, and it can be produced with very high conversion efficiency at relatively moderate capital cost. Several diesel truck and bus manufacturers have operated DME-fueled prototype vehicles, and pre-series production is imminent.
Swedish truck manufacturer AB Volvo, in a biofuels study, showed that the production of DME from harvest forestry woody biomass using the black liquor gasification process yields the highest miles per acre per year than biofuels produced by most other processes. Other studies show that the technology also yields the highest well-to-wheel greenhouse gas reduction and energy efficiency.
To facilitate its ability to ramp-up commercial scale black liquor gasification biorefineries at US pulp mills, Chemrec is actively pursuing federal and state grants and loan guarantees.
EU BioDME project website