(311d) Techno-Economics of Formate Assisted Pyrolysis

The purpose of this study is to determine the capital cost for producing liquid fuel from biomass by using Formate-Assisted Pyrolysis (FAsP) process. Many studies have been published about producing liquid fuel from biomass by using fast pyrolysis. Fast pyrolysis produces bio-oil with 60% mass yield; however, the bio-oil is unstable, has a high amount of oxygen 35 wt% and requires high capital cost to upgrade it. Formate-Assisted Pyrolysis (FAsP), a new method being developed at UMaine, produces a bio-oil that is more stable and has less amount oxygen. FAsP uses the same operating conditions as fast pyrolysis (500 °C and atmospheric pressure), but also integrates the thermal decomposition of formate salts.  Typical FAsP oil has 15 wt% oxygen and 34% energy yield. Experiments were done using different calcium formate/biomass ratios.

An Aspen Plus^® process model has been developed for a 1000 dry metric ton of biomass per day FAsP plant. The model includes feedstock sizing and drying, pyrolysis, hydrogen production and hydrotreatment of FAsP oils and recycle of calcium. The char is gasified to produce CO to regenerate calcium formate. Other gases from upgrading and pyrolysis are used to produce hydrogen which is necessary for bio-oil upgrading.  After the bio-oil is upgraded, the bio-oil is treated to reach a final 13% gasoline/diesel mass yield and 33% energy yield based on the dry biomass fed.