Study on the physicochemical structure and gasification reactivity of chars from pyrolysis of biomass pellets under different heating rates

Fuel ◽  
2021 ◽  
pp. 122789
Author(s):  
Qiang Hu ◽  
Wei Cheng ◽  
Qiaoting Mao ◽  
Junhao Hu ◽  
Haiping Yang ◽  
...  
Keyword(s):  
Heating Rates ◽  
Gasification Reactivity ◽  
Pyrolysis Of Biomass ◽  
Physicochemical Structure

Evolution of Gases from the Pyrolysis of Raw and Torrefied Biomass and from the Oxy-combustion of their Bio-Chars

2021 ◽  
pp. 1-30
Author(s):  
Xiaoxiao Meng ◽  
Wei Zhou ◽  
Emad Rokni ◽  
Xigang Yang ◽  
Yiannis Levendis
Keyword(s):  
Co2 Emissions ◽  
Carbon Capture ◽  
Heating Rates ◽  
Renewable Biomass ◽  
Carbon Capture And Utilization ◽  
Combustion Emissions ◽  
Torrefied Biomass ◽  
High Heating ◽  
Pyrolysis Of Biomass ◽  
N Compounds

Abstract The current research assessed the evolution of gases from pyrolysis of biomass and from subsequent combustion of bio-chars. Raw and torrefied biomass was pyrolyzed in nitrogen or carbon dioxide under high heating rates (104 K/s) and high temperatures (1450 K). Pyrolyzates gases were monitored for carbon, nitrogen and sulfur oxides. Subsequently, generated bio-chars were burned in both conventional (air) and simulated oxy-combustion (O2/CO2) gases. In principle, oxy-combustion of renewable biomass coupled with carbon capture and utilization/sequestration can help remove atmospheric CO2. Pyrolysis of biomass in CO2 generated lower char yields, lower SO2 and NO, and higher CO2, CO and HCN mole fractions, compared to pyrolysis in N2. HCN was the most prominent among all measured nitrogen-bearing gases (HCN, NH3, NO) from biomass pyrolysis. Compared to their combustion in air, bio-chars burned more effectively in 30%O2/79%CO2 and less effectively in 21%O2/79%CO2. Emissions of CO were the lowest in 21%O2/79%CO2. Emissions of HCN were the highest in air combustion, and decreased with increasing O2 mole fraction in oxy-combustion; emissions of NO were highest in 30%O2/79%CO2, and emissions of NO were dominant during bio-char oxy-combustion compared with other N-compounds. In oxy-combustion bio-chars released the lowest emissions of SO2. Finally, the emissions of CO, NO, HCN, and SO2 from combustion of DDGS bio-chars were higher than those from RH bio-chars, because of different physicochemical properties.

A Microreactor System for the Analysis of the Fast Pyrolysis of Biomass

2010 ◽  
Vol 2 (3) ◽  
Author(s):  
Alexander Williams ◽  
J. Rhett Mayor
Keyword(s):  
Fast Pyrolysis ◽  
Heating Rates ◽  
Experimental Heat ◽  
Experimental Heat Transfer ◽  
Study Results ◽  
Design Requirements ◽  
Layer Heating ◽  
The Individual ◽  
Pyrolysis Of Biomass ◽  
Good Agreement

A novel fast pyrolysis microreactor was developed to facilitate control over feedstock dwell time, pyrolysis temperature, and the individual collection of pyrolysis liquid and solid products. The design process followed is presented including design requirements, functional decomposition, commissioning tests, and the final microreactor design. A vibratory assisted spreading study was performed as particle agglomeration was a key challenge within the reactor design. The study results and analysis of variance are presented identifying the most significant factor and a best operating point. Analytical and experimental heat transfer analyses are also presented to validate the reactor’s thermal performance. Through the pairing of the analyses, projections for thin biomass layer heating rates are made resulting in estimates on the order of 400°C/s. Finally, experimental pyrolysis results are given showing fast pyrolysis conversion as a function of time and the process by which kinetic descriptors could be derived using this system’s results. Yield results are compared with literature and are found to be in good agreement with published fast pyrolysis results.

scholarly journals Influence of Thermal and Morphological Behaviour on Biomass Waste Materials during Pyrolysis

2021 ◽  
Vol 321 ◽  
pp. 01005
Author(s):  
Swapan Suman ◽  
Santosh Kumar Rai ◽  
Anand Mohan Yadav ◽  
Awani Bhushan ◽  
Nomendra Tomar ◽  
...  
Keyword(s):  
Reaction Model ◽  
Heating Rates ◽  
Nitrogen Gas ◽  
Thermo Gravimetric ◽  
Sem Images ◽  
Biomass Waste ◽  
Kinetics Parameters ◽  
Biomass Feedstocks ◽  
Different Types ◽  
Pyrolysis Of Biomass

Aim of this study to investigate the thermal and morphological behaviour of different types of biomass feedstock. For investigation of thermal behaviour we used thermo-gravimetric (TG) analysis and derivative thermo-gravimetric (DTG) analysis. The biomass feedstocks were conceded out under vigorous conditions using nitrogen gas at specific heating rates to gradient the temperature from 25°C to 1000°C. The derivative thermo-gravimetric (DTG) results show that thermal decomposition on these feedstocks. First-order reaction model were used to determine the kinetics parameters for the pyrolysis of biomass wastes. This study used Field Emission Scanning Electron Microscopy (FE-SEM) to observe surface morphology properties of the different biomass wastes. The FE-SEM images showed that clearly retained the fibrous structures in the biomass wastes and were rich in macro-pores.

Design, Development and Characterization of a Micro-Reactor for Fast Pyrolysis of Biomass Feedstocks

2008 ◽  
Author(s):  
J. Rhett Mayor ◽  
Alex Williams
Keyword(s):  
Particle Size ◽  
Heat Loss ◽  
Fast Pyrolysis ◽  
Reactor System ◽  
Design Development ◽  
Heating Rates ◽  
Reaction Surface ◽  
Pyrolysis Of Biomass ◽  
Micro Reactor

This paper presents the latest results in the design, development and performance characterization of a novel prototype micro-reactor system that is uniquely capable of capturing the transient product evolution history of the fast pyrolysis of biomass products. With strong demand driving the technological development of sustainable energy solutions, the consideration of optimal conversion methodologies for biomass energy feedstocks has received a great deal of attention recent years. [1, 2] The pyrolysis of soft woods, in particular spruce and pine, has emerged as a credible alternative to bio-digestive strategies that are reliant on fermentation processes, typically of corn feedstocks. The design objectives for the micro-reactor system are reviewed, highlighting the multi-physics and multi-disciplinary complexity in designing for transient characterization of the pyrolized products by the micro-reactor system. One of the dominant challenges in the design of the micro-reactor for fast pyrolysis reactions is the requirement of very high heating rates for the feedstock, on the order of 100°C/s. A 1D transient thermal model of the reactor is developed that considers the average particle size and morphology, the initial surface temperature of the reaction surface within the micro-reactor, the heat loss to the ambient atmosphere in the reactor, the heat loss through the contact resistance between the sample and the reaction surface and the thermal capacitance of the reaction surface. A parametric evaluation of the design space was performed using the 1D model in order to identify a preferred range of particle size, reactor surface area and thermal input power. Based on the results for the domain reduction study, multi-physics thermo-mechanical 3D FEA was used to undertake a brute-force optimization process of the final design. The key metric considered in the FEA study was the maximum thermal gradient in the reaction surface and was driven to a minimum value. The thermal response of the prototype micro-reactor has been evaluated using infra-red thermography measurement techniques. Thermographical analysis of the results has demonstrated negligible thermal gradients in the reaction plane up to the maximum reaction setpoint of 450°C. Based on the results of the thermal testing of the micro-reactor, the achieved peak heating rates of the sample have been estimated to be on the order of 400°C/s, meeting and exceeding the design requirement.

scholarly journals Conventional and microwave-assisted pyrolysis of biomass under different heating rates

2014 ◽  
Vol 107 ◽  
pp. 276-283 ◽  
Author(s):  
Chunfei Wu ◽  
Vitaliy L. Budarin ◽  
Mark J. Gronnow ◽  
Mario De Bruyn ◽  
Jude A. Onwudili ◽  
...  
Keyword(s):  
Heating Rates ◽  
Microwave Assisted ◽  
Pyrolysis Of Biomass

High Temperature Flash Pyrolysis of Wood in a Lab-Scale Solar Reactor

2014 ◽  
Author(s):  
Kuo Zeng ◽  
Daniel Gauthier ◽  
Gilles Flamant
Keyword(s):  
Heating Rate ◽  
Cfd Simulation ◽  
Vertical Axis ◽  
Solar Furnace ◽  
Heating Rates ◽  
Product Yields ◽  
Solar Reactor ◽  
Increasing Temperature ◽  
Sweeping Gas ◽  
Pyrolysis Of Biomass

Pyrolysis of biomass (wood) was studied at the focus of a 1.5 kW vertical axis solar furnace. The sweeping gas feeding system was designed based on the CFD simulation results. The effects of temperature on the product yields and compositions of gas were investigated by experiments performed at heating rate of 50°C/s up to 600, 800, 1000, and 1200°C. The role of heating rates influencing the product yields and gas composition was studied by experiments carried out at different heating rates of 5, 100, 25 °C/s to 1200°C. The results show that the increase of gas product from 27.7% to 47.8% with increasing temperature and heating rate comes from the tar decomposition. In the solar reactor, heating rate plays a more important role for the product yields than temperature does, which is different with respect to conventional reactors.

Pyrolytic Behavior and Kinetic Analysis of Wheat Straw and Lignocellulosic Biomass Model Compound

2013 ◽  
Vol 860-863 ◽  
pp. 550-554 ◽  
Author(s):  
Zhi Qiang Wu ◽  
Shu Zhong Wang ◽  
Jun Zhao ◽  
Lin Chen ◽  
Hai Yu Meng
Keyword(s):  
Activation Energy ◽  
Kinetic Analysis ◽  
Wheat Straw ◽  
Lignocellulosic Biomass ◽  
Nitrogen Atmosphere ◽  
Thermochemical Conversion ◽  
Heating Rates ◽  
Decomposition Rates ◽  
Model Compounds ◽  
Pyrolysis Of Biomass

From a carbon cycle perspective, the thermochemical conversion of lignocellulosic biomass is inherently carbon neutral. Pyrolysis of biomass for energy supplying, such as bio-oil and bio-char, has been attracted much attention worldwide. Successful understanding the fundamental issues about the pyrolysis, including pyrolytic behavior and kinetic analysis of lignocellulosic biomass model compounds and real biomass, is essential for the further understanding and optimizing the pyrolysis process. In this paper, pyrolytic behavior of a typical lignocellulosic agricultural residue (wheat straw) and model compounds (cellulose) were measured through thermogravimetric analysis with various heating rates (10, 20, 40 °C·min-1) under nitrogen atmosphere. The results indicated that the interval of the weight loss for both wheat straw and cellulose moved upwards with the increment of heating rates. The maximum decomposition rates of cellulose were higher than those of wheat straw, and the temperature of maximum decomposition rates increased with the heating rates. Values of activation energy were solved through iso-conversional method. And the average values of activation energy for wheat straw and cellulose were 146.89 kJ·mol-1 and 134.56 kJ·mol-1 calculated from Flynn-Wall-Ozawa method, 144.05 kJ·mol-1 and 130.91 kJ·mol-1 calculated from Kissinger-Akahira-Sunose method, respectively.

Investigation Into the Effects of Reaction Duration on the Isothermal Fast Pyrolysis of Biomass

2009 ◽  
Author(s):  
J. Rhett Mayor ◽  
Alexander Williams
Keyword(s):  
Loblolly Pine ◽  
Energy Content ◽  
Biomass Conversion ◽  
Fast Pyrolysis ◽  
Residence Times ◽  
Heating Rates ◽  
Reaction Duration ◽  
Bio Oil ◽  
Pyrolysis Of Biomass ◽  
Conversion Efficiencies

Bio-oils were produced within a fast-pyrolysis micro-reactor at 400°C from Loblolly Pine (Pinus Taeda) with varying residence times. This preliminary study has considered two boundary values for the residence time, evaluating the products of the reaction at 20 seconds and 120 seconds. The collected bio-oils were analyzed for their calorific values (LHV) and biomass conversion efficiencies. Heating rates greater than 100°C/s were achieved for the biomass, allowing for isothermal conditions to exist throughout the majority of the reaction despite short residence times. This study shows the effect that reaction duration has on the mass of the bio-oil yield and energy content present for the isothermal fast pyrolysis of Loblolly Pine and evaluates the predictive capabilities of TGA derived Arrhenius coefficients.

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