Techno-economic performance analysis of biofuel production and miniature electric power generation from biomass fast pyrolysis and bio-oil upgrading

The techno-economic performance analysis of biofuel production and electric power generation from biomass fast pyrolysis and bio-oil hydroprocessing is explored through process simulation. In this work, a process model of 72 MT/day pine wood fast pyrolysis and bio-oil hydroprocessing plant was developed with rate based chemical reactions using Aspen Plus® process simulator. It was observed from simulation results that 1 kg s−1 pine wooddb generate 0.64 kg s−1 bio-oil, 0.22 kg s−1 gas and 0.14 kg s−1 char. Simulation results also show that the energy required for drying and fast pyrolysis operations can be provided from the combustion of pyrolysis by-products, mainly, char and non-condensable gas with sufficient residual energy for miniature electric power generation. The intermediate bio-oil product from the fast pyrolysis process is upgraded into gasoline and diesel via a two-stage hydrotreating process, which was implemented by a pseudo-first order reaction of lumped bio-oil species followed by the hydrocracking process in this work. Simulation results indicate that about 0.24 kg s−1 of gasoline and diesel range products and 96 W of electric power can be produced from 1 kg s−1 pine wooddb. The effect of initial biomass moisture content on the amount of electric power generated and the effect of biomass feed composition on product yields were also reported in this study. Aspen Process Economic Analyser® was used for equipment sizing and cost estimation for an nth plant and the product value was estimated from discounted cash flow analysis assuming the plant operates for 20 years at a 10% annual discount rate. Economic analysis indicates that the plant will require £16.6 million of capital investment and product value is estimated at £6.25/GGE. Furthermore, the effect of key process and economic parameters on product value and the impact of electric power generation equipment on capital cost and energy efficiency were also discussed in this study

Comparative evaluation of GHG emissions from the use of Miscanthus for bio-hydrocarbon production via fast pyrolysis and bio-oil upgrading

This study examines the GHG emissions associated with producing bio-hydrocarbons via fast pyrolysis of Miscanthus. The feedstock is then upgraded to bio-oil products via hydroprocessing and zeolite cracking. Inventory data for this study were obtained from current commercial cultivation practices of Miscanthus in the UK and state-of-the-art process models developed in Aspen Plus®. The system boundary considered spans from the cultivation of Miscanthus to conversion of the pyrolysis-derived bio-oil into bio-hydrocarbons up to the refinery gate. The Miscanthus cultivation subsystem considers three scenarios for soil organic carbon (SOC) sequestration rates. These were assumed as follows: (i) excluding (SOC), (ii) low SOC and (iii) high (SOC) for best and worst cases. Overall, Miscanthus cultivation contributed moderate to negative values to GHG emissions, from analysis of excluding SOC to high SOC scenarios. Furthermore, the rate of SOC in the Miscanthus cultivation subsystem has significant effects on total GHG emissions. Where SOC is excluded, the fast pyrolysis subsystem shows the highest positive contribution to GHG emissions, while the credit for exported electricity was the main ‘negative’ GHG emission contributor for both upgrading pathways. Comparison between the bio-hydrocarbons produced from the two upgrading routes and fossil fuels indicates GHG emission savings between 68% and 87%. Sensitivity analysis reveals that bio-hydrocarbon yield and nitrogen gas feed to the fast pyrolysis reactor are the main parameters that influence the total GHG emissions for both pathways

Quantitative insights into the fast pyrolysis of extracted cellulose, hemicelluloses and lignin

The transformation of lignocellulosic biomass into bio-based commodity chemicals is technically possible. Among thermochemical processes, fast pyrolysis, a relatively mature technology that has now reached the commercial level, produces a high yield of an organic-rich liquid stream. Despite the recent efforts in elucidating the degradation paths of biomass pyrolysis, the selectivity and recovery rates of bio-compounds remain low. In an attempt to clarify the general degradation scheme of biomass fast pyrolysis and provide a quantitative insight, this study has combined the use of fast pyrolysis micro-reactors, spectrometric techniques and mixtures of unlabelled and Carbon-13 enriched materials. The first stage of the work reported aimed at selecting the type of reactor to ensure control of the pyrolysis regime. The comparison of chemical fragmentation patterns of 'primary' fast pyrolysis volatiles detectable by GC-MS between two small scale micro-reactors has shown the inevitable presence of secondary reactions. In a second stage, liquid fractions also made of 'primary' fast pyrolysis condensables have been analysed by quantitative liquid-state 13C-NMR providing a quantitative distribution of functional groups. The compilation of those results into a map that displays the distribution of functional groups according to the individual and main constituents of biomass confirmed the origin of individual chemicals within fast pyrolysis liquids

Release Profile of Nitrogen during Thermal Treatment of Waste Wooden Packaging Materials

In this paper, the fast pyrolysis experiment of particle board was carried out on a fixed bed reactor and a Py-GC/MS equipment. The effects of temperature and gas phase residence time on the product yields and its components distribution were investigated. The effect of components of particle board on product yields and its components distribution was also investigated. The results showed that the temperature has a great influence on the yields of fast pyrolysis products, and the yield of pyrolysis oil reached the highest at 550°C. The urea-formaldehyde resin would prevent the pyrolysis of particle board. Compared with the bio-oil from fast pyrolysis of wood, the major components of the bio-oil from fast pyrolysis of particle board did not change much

Biomass Fast Pyrolysis

Biomass is becoming an increasingly important alternative resource of energy supply. Bioenergy can replace the fossil fuels for a lot of reasons, such as economics, renewability, and fewer greenhouse gases. In this study, a mathematical model for the reactions in fast pyrolysis of a single biomass particle is simulated (Heindel, Xue and Fox, 2011). The solid biomass particle is assumed to consist of cellulose, hemicellulose and lignin, and these are converted by rapid heating into active components and then eventually into tar and gas (Heindel, Xue and Fox, 2011). Using existing values for the reaction rates and assuming a constant temperature, the evolution equations for the mass fraction of components are simulated in time. The model is then extended to account for transient heat and mass transfer between the biomass particle and the ambient gas. Finally, a stochastic description of the problem is presented where a distribution of ambient gas temperature is considered. The effect of the stochastic variability of ambient temperature on the yield of biomass conversion is investigated

Effects of ash removal by agitated aqueous washing and sedimentation on the physico-chemical characteristics and fast pyrolysis of trommel fines

A pre-treated trommel fines feedstock (DPT) with 35.1 wt% ash content and particle size range of 0.5–2 mm was processed through two (100% distilled water and 1% surfactant in distilled water) aqueous agitated washing and sedimentation procedures for ash reduction prior to fast pyrolysis in a bubbling fluidized bed reactor. The washing process led to more than 36% reduction in the ash/inorganic contents of the DPT feedstock and yielded about 78 wt% of organic-rich feedstocks denoted as WPT1 and WPT2. Characterisation and fast pyrolysis of all three feedstocks was carried out to evaluate the effect of the washing process on their physico-chemical characteristics and yields of fast pyrolysis products. Results showed that the ash reduction led to increase in the volatile matter contents of the washed feedstocks by 20%, while reducing nitrogen contents. In addition, fast pyrolysis of the feedstocks showed improved yield of liquid and gas products, with a dramatic reduction of reaction water, indicating that the ash removal reduced the catalytic effect of the ash on water formation during the fast pyrolysis process. The major organic compounds in the liquid products included phenols and furans from biogenic fraction of the feedstock as well as aromatic hydrocarbons such as those obtained from pyrolysis of plastics. More importantly, the overall energy yields from the fast pyrolysis process increased by over 35% after washing the feedstock, with washing with only distilled water alone giving the highest energy yield of 93%. Hence, coupling the water-washing ash reduction process with fast pyrolysis appeared to be a suitable technology for valorising feedstocks with high ash contents such as trommel fines for energy and chemicals

Manipulation of product distributions in biomass fast pyrolysis using molten polymers

Biomass fast pyrolysis has attracted significant attention due to high yields (\u3e 75 wt%) of liquid products. A major drawback to biomass fast pyrolysis is the diverse product distributions of this liquid fraction, making subsequent upgrading and separation operations expensive. Using catalysts to accelerate pathways to desired products have been actively researched to resolve this problem. A complementary strategy is to suppress undesired pathways via inhibition, which is commonly utilized in enzymatic, combustion, and polymerization reactions but rarely explored in biomass fast pyrolysis. Please click Additional Files below to see the full abstract

A Characterization Of The Fast Pyrolysis Of Cellulose And Wood Biomass

The science of biomass fast pyrolysis is relatively young and incomplete. To date, there has been no systematic attempt to define fast pyrolysis in terms of chemistry, product distribution, kinetics, heat transfer requirements, and requisite process conditions. Neither has there been any experimental work which tracks the reaction progress as a function of both temperature and residence time. Furthermore, the literature provides a fragmented and often contradictory view of the nature of fast pyrolysis.;This thesis provides a coherent picture of the fast pyrolysis of cellulose and wood via an extensive literature review and systematic research. The literature review is an essential element of the thesis. It is not an uncritical summary, but is an interpretive integration of published knowledge. As such, it provides a comprehensive structure for the characterization of biomass fast pyrolysis.;The literature review suggests that fast pyrolysis reactions consist of biomass activation followed by primary fragmentation and secondary vapour-phase cracking; the secondary cracking reactions are the focus of the thesis experimental work. This work was carried out predominantly in the Ultrapyrolysis plant at the University of Western Ontario, and to a lesser degree in the RTP plant at Ensyn Technologies Inc.;Both reactor systems provide extremely rapid heat transfer to biomass combined with precise control of short residence times. In order to prove the integrity and reliability of the hardware, initial work involved the rapid pyrolysis of a model compound (ethane) and a comparison of the use of both gaseous and solid particulate heat transfer media. The cornerstone work involved the systematic characterization of the product distribution of secondary cracking reactions as a function of temperature and residence time. The ranges of temperatures and residence times under investigation were 650 to 900{dollar}\sp\circ{dollar}C and 30 ms to 1 s, respectively. The data from this work was used to generate rate equations for the secondary reactions of cellulose and wood fast pyrolysis. Finally, a cooperative study was conducted with the University of Waterloo to compare cellulose fast pyrolysis results from two independent reactor systems. The joint study exhibited excellent agreement and congruity over a broad range of pyrolysis temperatures