Catalytic fast pyrolysis of pine sawdust was successfully carried out in VTT's 20 kg h −1 Process Development Unit using a spray dried HZSM-5 catalyst. Approximately 250 kg of partially deoxygenated pyrolysis oil was produced over a period of four days. The catalytically produced pyrolysis oil had an average moisture content of 8.3 wt%, and average carbon and oxygen contents of 72.0 and 21.5 wt% on a dry basis, respectively. Approximately 24% of the original biomass carbon was present in the pyrolysis oil, whereas 14% of carbon was in the form of aqueous side products, which totaled approximately 600 kg. The pyrolysis oil contained a high amount of lignin derived water-insoluble material, as well as 6.4 wt% of aromatic hydrocarbons. The majority of the carbohydrate derived products, i.e. acids, aldehydes, ketones and sugar-type compounds, were found in the aqueous product fraction. While the quality of pyrolysis oil remained quite stable during the four day experiment, distinct changes were observed in the properties and the behavior of the catalyst. Coke formation was heaviest at the beginning of the experiment, and then subsided over time. Catalyst micropore area and volume also decreased during the experiment. This transformation was accompanied by apparent changes in the crystallinity and the structure of the catalyst. Scanning electron microscope images of the catalyst also revealed clear physical damage to the particles. Biomass alkali metals also deposited on the catalyst, and the spent catalyst contained a total of 1.1 wt% of Ca, K, Mg and P after the experiment. A linear correlation was observed between catalyst alkali metal content and acidity, which indicated that biomass alkalis substituted the proton functionalities of the HZSM-5 acid sites. † Electronic supplementary information (ESI) available. See
The review summarizes VTT fast pyrolysis development efforts from the past 40 years. The experimental work has included a large variety of feedstocks (biomasses, wastes, oil shale, and plastic residues) and a variety of products (heating oils, refinery feeds, transportation fuels, and chemicals). As a result of the constant turbulence on fossil oil prices and changing regulatory framework, only a few renewable product alternatives are economically competitive. Plastic wastes appear to offer currently the most promising industrial opportunities.
Metso, UPM, Fortum, and VTT have developed the world’s first integrated bio-oil production concept to provide an alternative to fossil fuels. The consortium has constructed an up to 7 tons/day bio-oil production pilot unit, which uses a bubbling fluidized-bed (BFB) pyrolysis reactor integrated with a conventional fluidized-bed boiler. Proof-of-concept has been carried out; close to 90 tons of bio-oil has been produced from sawdust and forest residues at high availability. Around 40 tons of bio-oil has been combusted in Fortum’s 1.5 MW district heating plant in Masala, Finland, with high efficiency. Flue gas emissions were close to those of heavy fuel oil, at 4% O2, CO emissions ranged from 0 to 10 ppm and NO x emissions ranged from 300 to 400 ppm. Organic compounds were under 5 mg m–3 N–1, and particulate emissions were in the range of 150–200 mg m–3 N–1. No odor emissions occurred. Development of the concept has been supported by experimental work on fast pyrolysis at VTT. This paper presents the recent results from the piloting project covering the whole chain from feedstock processing to bio-oil combustion, including the quality control system with online gas and liquid analyzers. The research supporting the pilot project, from various laboratory-scale units to systematic analytical development, is discussed, and the potential for market introduction of the new technology in forest product industries in western Europe and North America is described.
A steady-state Aspen Plus simulation model has been developed that provides estimated mass and energy balances for an industrial fluidizing-bed fast pyrolysis process to produce bio-oil. The tool can be used to assess plant performance under varying process conditions using different feedstocks. A 30 MW lower heating value (LHV) bio-oil plant was modeled utilizing two different feedstock types (pine and forest residues). The fast pyrolysis product yields are functions of feedstock ash content and were calculated on the basis of data generated by a 0.5 t/d fast pyrolysis test unit. The UNIQUAC activity coefficient method was used for the calculation of the liquid phase, and the ideal-gas fugacity coefficient method was used for the vapor-phase calculations. Modeling of the condensation of fast pyrolysis vapors was also verified against experimental data gained from the 0.5 t/d test unit. Production costs were estimated for the two concepts. The results show that the pine-based fast pyrolysis process has better process efficiency and lower production costs compared with the forest-residue-based process. The total estimated capital investment costs including plant fixed capital investment (FCI), startup, working capital, and interest over construction period were estimated to be 24 and 28 M€ for the pine-and forest-residue-based processes, respectively. Sensitivity analyses showed that the bio-oil quality and bio-oil production efficiency can be improved by drying the recycle gas. Varying the production cost parameters within an industrially relevant range resulted in a production cost of bio-oil between 50 and 70 €/MWh. However, unless the wood price is lower than current market price (20 €/MWh assumed here) or excess heat may be valued higher than the fuel price, production is not currently competitive compared with fossil alternatives.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.