The Characteristics of Products from Pyrolysis of Seaweed in Molten Carbonates

2019 ◽  
Vol 62 (3) ◽  
pp. 787-794
Author(s):  
Yi Wei ◽  
Jitong Tang ◽  
Jianbing Ji
Keyword(s):  
Heat Transfer ◽  
Thermogravimetric Analysis ◽  
Molten Salts ◽  
Molten Carbonate ◽  
Gas Generation ◽  
Slow Pyrolysis ◽  
Gaseous Products ◽  
Molten Carbonates ◽  
Bio Oil ◽  
Terrestrial Biomass

Abstract. The characteristics of the seaweed (SH) were investigated as a feedstock for slow pyrolysis and molten carbonate (MC) pyrolysis within the temperature range of 400°C to 600°C. SH differs from terrestrial biomass in its constitutional compounds and high N content. According to thermogravimetric analysis, decomposition of proteins and cellulose played the most important role in thermal degradation of SH. The yields and distributions of syngas and bio-oil from MC pyrolysis varied with temperature and were greatly different from those of slow pyrolysis. MC pyrolysis increased gas generation by 10.46 wt% while reducing solids yield from 38.10 wt% to 31.99 wt% at 600°C. Of the gaseous products, H2 was dominant, and CO2 was also prominent. Conversion of tar and acid in the bio-oil was significantly improved in the molten salts medium, while nitrogen content was significantly reduced in the bio-oil. MC pyrolysis minimized the obstacles to heat transfer during pyrolysis by heating the feedstock from both inside and outside. Keywords: Intensification, Molten carbonates, Pyrolysis, Sargassum horneri.

Slow pyrolysis of bio-oil and studies on chemical and physical properties of the resulting new bio-carbon

2018 ◽  
Vol 172 ◽  
pp. 2748-2758 ◽  
Author(s):  
Stefanie Arnold ◽  
Arturo Rodriguez-Uribe ◽  
Manjusri Misra ◽  
Amar K. Mohanty
Keyword(s):  
Physical Properties ◽  
Slow Pyrolysis ◽  
Bio Oil

scholarly journals Nusselt number evaluation for combined radiative and convective heat transfer in flow of gaseous products from combustion

2013 ◽  
Vol 17 (4) ◽  
pp. 1093-1106 ◽  
Author(s):  
Soraya Trabelsi ◽  
Wissem Lakhal ◽  
Ezeddine Sediki ◽  
Mahmoud Moussa
Keyword(s):  
Heat Transfer ◽  
Radiation Effects ◽  
Combustion Products ◽  
Radiative Properties ◽  
Inlet Temperature ◽  
Gaseous Products ◽  
Nusselt Numbers ◽  
Coupled Heat Transfer ◽  
Flow And Heat Transfer ◽  
Fluid Properties

Combined convection and radiation in simultaneously developing laminar flow and heat transfer is numerically considered with a discrete-direction method. Coupled heat transfer in absorbing emitting but not scattering gases is presented in some cases of practical situations such as combustion of natural gas, propane and heavy fuel. Numerical calculations are performed to evaluate the thermal radiation effects on heat transfer through combustion products flowing inside circular ducts. The radiative properties of the flowing gases are modeled by using the absorption distribution function (ADF) model. The fluid is a mixture of carbon dioxide, water vapor, and nitrogen. The flow and energy balance equations are solved simultaneously with temperature dependent fluid properties. The bulk mean temperature variations and Nusselt numbers are shown for a uniform inlet temperature. Total, radiative and convective mean Nusselt numbers and their axial evolution for different gas mixtures produced by combustion with oxygen are explored.

scholarly journals Kinetics study on non-isothermal thermochemical liquefaction of corncobs in ethanol-water solution: Effect of ethanol concentration

2018 ◽  
Vol 197 ◽  
pp. 09005
Author(s):  
Bregas Siswahjono Tatag Sembodo ◽  
Hary Sulistyo ◽  
Wahyudi Budi Sediawan ◽  
Mohammad Fahrurrozi
Keyword(s):  
Experimental Data ◽  
Kinetic Models ◽  
Ethanol Concentration ◽  
Water Solution ◽  
Reaction Products ◽  
Gaseous Products ◽  
Bio Oil ◽  
Volatile Products ◽  
Calculation Results ◽  
Oil Gas

Corncobs are potentially processed into bio-oil through thermochemical liquefaction processes. It is difficult to construct kinetics models based on the compounds involved in the reaction. It would be made four kinetic models based on four reaction products, i.e., solids, bio-oil, gas and volatile products. The purposes of the study were to seek kinetics model of thermochemical liquefaction of corncobs in ethanol-water solution and to study the effect of ethanol concentration. The experiment of liquefaction processes of corncobs in ethanol-water solution using sodium carbonate catalyst was performed in the 150 ml autoclave equipped with a magnetic stirrer in the temperature up to 280°C. Four kinetic models were applied to predict the yield of four reaction product lumps. The calculation results were compared to the experimental data. Compared to the others, model 4 was the most realistic and closely matching to the experimental data. In model 4 the reaction mechanism was assumed that biomass (corncobs) first decomposed into bio-oil, followed by decomposition of bio-oil into volatile products reversibly and, finally, volatile products decomposed into gaseous products. The yield of bio-oil increased from 42.05% to 54.93% by increasing to ethanol concentration of 0% to 40%.

Preparation and Thermal Properties of High-Purified Molten Nitrate Salt Materials with Heat Transfer and Storage

2015 ◽  
Vol 34 (8) ◽  
Author(s):  
Hongtao Zhang ◽  
Youjing Zhao ◽  
Jingli Li ◽  
Lijie Shi ◽  
Min Wang
Keyword(s):  
Heat Transfer ◽  
Thermal Stability ◽  
Thermal Properties ◽  
Molten Salts ◽  
Operating Temperature ◽  
Nitrate Salt ◽  
Solar Salt ◽  
And Storage ◽  
Thermal Stability Of ◽  
Operating Temperature Range

AbstractThis paper focuses on thermal stability of molten salts, operating temperature range and latent heat of molten salts at a high temperature. In this experiment, multi-component molten salts (purified Solar Salt) composed of purified NaNO

Heat Transfer Technology to Convert Plastic Trash to Oil

2017 ◽  
Author(s):  
Mahmoud Elsharafi ◽  
Cody Chancellor ◽  
Cameron Duckworth ◽  
Moiz Tatla ◽  
Reuben Denwe ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Feedback Loop ◽  
Modern Society ◽  
Environmental Issue ◽  
Heating Rates ◽  
Waste Plastic ◽  
Control Temperature ◽  
The Road ◽  
Gaseous Products ◽  
Plastic Type

In modern society, plastic waste has become a serious environmental issue. The inability of most hydrocarbon based plastics to naturally decompose quickly causes concern. The material piles up in landfills, waterways, and along the side of the road. One way to combat this issue is the repurposing of the material. Plastic can be converted back into oil (called pyrolysis) and refined to produce fuels. To attempt this, a custom-built steel reactor is to be filled with waste plastic, and will be heated to the plastic’s boiling point in an inert (N2) environment. The resulting vapor will be recondensed in a specially designed heat exchanger, resulting in oil, wax, and gaseous byproducts. The oil and waxes are collected in one container, and the gases are collected in a separate container. The system will require the use of thermocouples and a feedback loop to properly control temperature. The results are expected to show a correlation between plastic type and resulting byproduct composition with Grade 1 plastics producing the most gas. In addition, faster heating rates, larger plastic particle size, and higher temperatures should increase gaseous products. This may aid in the creation of commercial/industrial sized pyrolysis systems.

scholarly journals Sub- and Supercritical Water Liquefaction of Kraft Lignin and Black Liquor Derived Lignin

Energies ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3309 ◽  
Author(s):  
Jukka Lappalainen ◽  
David Baudouin ◽  
Ursel Hornung ◽  
Julia Schuler ◽  
Kristian Melin ◽  
...  
Keyword(s):  
Supercritical Water ◽  
Renewable Energy Sources ◽  
Black Liquor ◽  
Hydrothermal Liquefaction ◽  
Water Soluble ◽  
Gaseous Products ◽  
Bio Oil ◽  
Water Conditions ◽  
Oil Water ◽  
Alkali Salts

To mitigate global warming, humankind has been forced to develop new efficient energy solutions based on renewable energy sources. Hydrothermal liquefaction (HTL) is a promising technology that can efficiently produce bio-oil from several biomass sources. The HTL process uses sub- or supercritical water for producing bio-oil, water-soluble organics, gaseous products and char. Black liquor mainly contains cooking chemicals (mainly alkali salts) lignin and the hemicellulose parts of the wood chips used for cellulose digestion. This review explores the effects of different process parameters, solvents and catalysts for the HTL of black liquor or black liquor-derived lignin. Using short residence times under near- or supercritical water conditions may improve both the quality and the quantity of the bio-oil yield. The quality and yield of bio-oil can be further improved by using solvents (e.g., phenol) and catalysts (e.g., alkali salts, zirconia). However, the solubility of alkali salts present in black liquor can lead to clogging problem in the HTL reactor and process tubes when approaching supercritical water conditions.

A Numerical Study of Fast Pyrolysis of Beetle Killed Pine Trees

2011 ◽  
Author(s):  
Saeed Danaei Kenarsari ◽  
Yuan Zheng
Keyword(s):  
Heat Transfer ◽  
Chemical Kinetics ◽  
Fast Pyrolysis ◽  
Kinetics Model ◽  
Unsteady State ◽  
Pyrolysis Process ◽  
Conservation Equations ◽  
Gaseous Products ◽  
Pine Trees ◽  
Secondary Reactions

Since 1990s, as a result of unprecedented drought and warm winters, mountain pine beetles have devastated mature pine trees in the forests of western North America from Mexico to Canada. Especially, in the State of Wyoming, there are more than 1 million acres of dead forest now. These beetle killed trees are a source of wildfire and if left unharvested will decay and release carbon back to the atmosphere. Fast pyrolysis is a promising method to transfer the beetle killed pine trees into bio-oils. In the present study, an unsteady state mathematical model is developed to simulate the fast pyrolysis process, which converts solid pine wood pellets into char (solid), bio-oils (liquid) and gaseous products in the absence of oxidizer in a temperature range from 500°C to 1000°C within short residence time. The main goal of the study is to advance the understanding of kinetics and convective and radiative heat transfer in biomass fast pyrolysis process. Conservation equations of total mass, species, momentum, and energy, coupled with the chemical kinetics model, have been developed and solved numerically to simulate fast pyrolysis of various cylindrical beetle killed pine pellets (10 mm diameter and 3 mm thickness) in a reactor (30 mm inside diameter and 50 mm height) exposed to various radiative heating flux (0.2 MW/m2 to 0.8 MW/m2). A fast pyrolysis kinetics model for pine wood that includes competitive path ways for the formation of solid, liquid, and gaseous products plus secondary reactions of primary products has been adapted. Several heat transfer correlations and thermo property models available in the literature have been evaluated and adapted in the simulation. Finite element method is used to solve the conservation equations and a 4th order Runge-Kutta method is used to solve the chemical kinetics. Unsteady-state two dimensional temperature and product distributions throughout the entire pyrolysis process were simulated and the simulated product yields were compared to the experimental data available in the literature. This study demonstrates the importance of the secondary reactions and appropriate convective and radiative modeling in the numerical simulation of biomass fast pyrolysis.

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