scholarly journals Effect of Steam on the Homogeneous Conversion of Tar Contained from the Co-Pyrolysis of Biomass and Plastics

2021 ◽  
Author(s):  
Feng Tang ◽  
Yuqi Jin ◽  
Yong Chi ◽  
Zhongxu Zhu ◽  
Jie Cai ◽  
...  
Keyword(s):  
Fixed Bed ◽  
Apparent Effect ◽  
Subsequent Reaction ◽  
Furnace Temperature ◽  
Atom Ratio ◽  
Pyrolysis Tar ◽  
Tar Cracking ◽  
Two Stages ◽  
Hydrogen Radicals ◽  
Pyrolysis Of Biomass

Abstract The co-pyrolysis tar formed from microcrystalline cellulose (MCC) and polyethylene (PE) was used to study their further conversion path under the effect of steam. This paper addressed the yield and transformation of tar with different steam/feedstock mass ratios (S/F= 0.8, 1.6) in a two-stage fixed-bed when the two stages furnace temperature was set at 600℃ and 800℃, separately. Compared with pyrolysis, steam promoted tar cracking effectively, the tar yield decreased at least 1/3. However, with the addition of steam, the cracking effect of tar is not further improved. The tar yield depended more on the PE content in the mixture, which was enhanced with PE increment. Besides, the H/C atom ratio was related to the conversion path of tar. Steam was beneficial to the cracking of compounds, but the generated hydrogen radicals affected the direction of the subsequent reaction. The steam mainly promotes the cracking of long-chain hydrocarbons, accompanied by cyclization and aromatization when the steam was limited. Nevertheless, these reactions were hindered when the steam was excessive due to the apparent effect of hydrogenation. In this process, the short-chain hydrocarbons come to recombine instead of cyclization and aromatization.

scholarly journals Fixed bed pyrolysis of biomass solid waste for bio-oil

2017 ◽  
Author(s):  
Mohammad Nurul Islam ◽  
Mohamed Hairol Md Ali ◽  
Miftah Haziq
Keyword(s):  
Solid Waste ◽  
Fixed Bed ◽  
Bio Oil ◽  
Pyrolysis Of Biomass

Operation of a Circulating Fluidised Bed Biomass Gasifier

2004 ◽  
Author(s):  
Guanyi Chen ◽  
Gang Li ◽  
Michel P. Glazer ◽  
Chunlei Zhang ◽  
J. Andries
Keyword(s):  
Large Scale ◽  
Fixed Bed ◽  
Calorific Value ◽  
Producer Gas ◽  
Fluidised Bed ◽  
Fuel Gas ◽  
Promising Alternative ◽  
Tar Cracking ◽  
Shift Reaction ◽  
Circulating Fluidised Bed

Energy generation from the use of biomass is gaining an increasing attention. Gasification of biomass at present, is widely accepted as a popular technical route to produce fuel gas for the application in boilers, engine, gas/micro turbine or fuel cell. Up to now, most of researchers have focused their attentions only on fixed-bed gasification and fluidised bed gasification under air-blown conditions. In that case, the producer gas is contaminated by high tar contents and particles which could lead to the corrosion and wear of blades of turbine. Furthermore, both the technologies, particularly fixed bed gasification, are not flexible for using multiple biomass-fuel types and also not feasible economically and environmentally for large scale application up to 10∼50 MWth. An innovative circulating fluidised bed concept has been considered in our laboratory for biomass gasification thereby overcoming these challenges. The concept combines and integrates partial oxidation, fast pyrolysis (with an instantaneous drying), gasification, and tar cracking, as well as a shift reaction, with the purpose of producing a high quality of gas, in terms of low tar level and particulates carried out in the producer gas, and overall emissions reduction associated with the combustion of producer gas. This paper describes our innovative concept and presents some experimental results. The results indicate that the gas yield can be above 1.80Nm3/kg with the calorific value of 4.5–5.0MJ/Nm3, and the fluctuation of the gas yield during the period of operation is 3.3%–3.5% for the temperature of 750–800 °C. In genera, the results achieved support our concept as a promising alternative for the gasifier coupled with micro/gas turbine to generate electricity.

Production of Hydrogen-Rich Gas Through Pyrolysis of Biomass in a Two-Stage Reactor

2004 ◽  
Author(s):  
Guanyi Chen ◽  
Qiang Li ◽  
Xiaoyang Lv ◽  
Na Deng ◽  
Lifei Jiao
Keyword(s):  
Rice Straw ◽  
Fixed Bed ◽  
Space Velocity ◽  
Corn Stalk ◽  
Two Stage ◽  
Gaseous Products ◽  
Production Of Hydrogen ◽  
Gas Space ◽  
Energy Products ◽  
Pyrolysis Of Biomass

Biomass is quite abundant in the world, particularly in some countries like China. China has large quantities of straw and/or stalk-origin biomass resources and the attention is currently being paid to the exploitation of these resources to produce energy products via different technical solutions, among of which pyrolysis of biomass to produce hydrogen-rich gas is very promising as hydrogen is a very clear energy carrier. In this work, pyrolysis of rice straw, corn stalk and sawdust was carried out in a two-stage reactor (the first-stage reactor is a conventional fixed-bed pyrolyser, and the second-stage reactor is a catalytic fixed bed) to produce hydrogen-rich gas. The effect of catalytic bed on the pyrolysis behaviour have been investigated, with the emphasis on final product particularly hydrogen. The operation of the catalytic reactor appears significant in promoting biomass pyrolysis towards the production of gaseous products, especially hydrogen. At 750°C of the pyrolyser with rice straw as fuel, the use of the catalytic bed leads to the increases of gas yield from 0.41 Nm3/kg to 0.50 Nm3/kg, approximately 22% increase, and of H2 concentration from 33.79% to 50.80% in volume, approximately 50.3% increase, respectively. Compared with calcined dolomite, fresh nickel-based catalyst shows stronger catalytic effect on the pyrolysis of rice straw as its use in the catalytic bed results in the increase of gas yield from 0.41 Nm3/kg to 0.56 Nm3/kg, approximately 36.6% increase, and the increase of H2 concentration from 33.79% to 59.55% in volume, approximately 76.2% increase. Furthermore, two catalysts follow the same trend for the pyrolysis of corn stalk and sawdust. At temperature of 815°C, catalysts also follow the same trend. Catalytic bed can significantly reduce the level of tar which is carried out with the producer gas, to less than 1% of original level. Catalyst load or gas space velocity (hourly) has the influence on the gas yield and H2 concentration. 30% of load, i.e. gas space velocity (hourly) 0.9 × 104 h−1, appears reasonable. Beyond that, gas yield and H2 concentration remain almost unchanged.

scholarly journals Thermal Decomposition and Thermal Reaction Process of PTFE/Al/MnO2 Fluorinated Thermite

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2451 ◽  
Author(s):  
Jun Zhang ◽  
Junyi Huang ◽  
Xiang Fang ◽  
Yuchun Li ◽  
Zhongshen Yu ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Control Systems ◽  
Thermal Reaction ◽  
Reaction Process ◽  
Reaction Products ◽  
Subsequent Reaction ◽  
Comparison Results ◽  
Different Temperatures ◽  
Xrd Phase Analysis ◽  
Two Stages

To better understand the thermal decomposition and reaction process of a fluorine-containing powdery thermite, PTFE/Al/MnO2, reactions at different temperatures were investigated by the TG/DSC-MS technique. The corresponding reaction products were characterized with XRD phase analysis. Another three thermite materials, i.e., PTFE/Al, Al/MnO2, and PTFE/MnO2, were also prepared for comparison. Results showed that PTFE behaved as both oxidizer and reducer in PTFE/Al/MnO2 fluorinated thermite. The thermal decomposition and reaction process of as-fabricated ternary thermite could be divided into two stages—the mutual reaction between each of PTFE, Al, and MnO2 and the subsequent reaction produced between Al and Mn2O3/Mn3O4/MnF2. Compared with the three control systems, the specially designed ternary system possessed a shorter reaction time, a faster energy release rate, and a better heat release performance.

Transformation and release of potassium during fixed-bed pyrolysis of biomass

2018 ◽  
Vol 91 (4) ◽  
pp. 630-637 ◽  
Author(s):  
Lei Deng ◽  
Jiaming Ye ◽  
Xi Jin ◽  
Defu Che
Keyword(s):  
Fixed Bed ◽  
Pyrolysis Of Biomass

Hydrogen production via catalytic pyrolysis of biomass in a two-stage fixed bed reactor system

2014 ◽  
Vol 39 (25) ◽  
pp. 13128-13135 ◽  
Author(s):  
Shaomin Liu ◽  
Jinglin Zhu ◽  
Mingqiang Chen ◽  
Wenping Xin ◽  
Zhonglian Yang ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Catalytic Pyrolysis ◽  
Fixed Bed ◽  
Reactor System ◽  
Fixed Bed Reactor ◽  
Two Stage ◽  
Pyrolysis Of Biomass

scholarly journals Experimental studies of intermediate pyrolysis of woody and agricultural biomass in a fixed bed reactor

2021 ◽  
Vol 323 ◽  
pp. 00003
Author(s):  
Artur Bieniek ◽  
Wojciech Jerzak ◽  
Aneta Magdziarz
Keyword(s):  
Raw Materials ◽  
Volume Flow Rate ◽  
Fixed Bed ◽  
Experimental Studies ◽  
Fixed Bed Reactor ◽  
Process Conditions ◽  
Heating Value ◽  
Ultimate Analysis ◽  
Intermediate Pyrolysis ◽  
Pyrolysis Of Biomass

Biomass pyrolysis is an advanced process which leads to obtaining products as chars, primary tars and gases. Depending on pyrolysis conditions and reactor construction, the pyrolysis could be divided into three categories: slow, intermediate and fast. This work concerns the experimental analysis of an intermediate pyrolysis of biomass residues in a fixed bed reactor. As raw materials, pine bark and wheat straw were selected. Experiments were carried out at three temperatures: 400, 500 and 600 °C under constant volume flow rate of inert gas equal to 100 ml/min. Biomass samples were kept for 150 seconds in the hot zone. The main goal was to compare yields, elemental composition, and calorific values of received products under studied process conditions. The ultimate analysis of chars and organic fractions of oils was performed. Obtained results from ultimate analysis allowed to determine higher heating values by a theoretical correlation. The products of pyrolysis obtained at 600 °C characterized by the most energetic parameters. The higher heating value for organic fraction of tars was 31.62 MJ/kg while for char was 29.47 MJ/kg.

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