Chemical Engineering Commons^™

Comparison Of Biomass To Bio-Oils Reactor Systems: Direct Conversion Vs. Companion Coal Gasification, Alexandra Eicher

Honors Theses and Capstones

It is well known that the United States’ dependence on crude-oil negatively affects its economy, safety, and environment. To alleviate these negative consequences, a more economical and environmentally-friendly source of fuel, such as biomass, should be explored. The conversion of biomass to bio-oils involves the pyrolysis of biomass at about 500°C, thus requiring a great deal of heat. This heat source could be the excess waste heat from a coal gasifier.

As such, this report specifies the design of an industrial plant that produces bio-oils from biomass by using the waste heat from a coal gasifier. It is designed to …

Married Coal Gasification And Biomass Pyrolysis, Michael Balch

Honors Theses and Capstones

This project is a proposal to marry a coal gasification process to a biomass pyrolysis. Coal is pyrolized to produce syngas and a large amount of heat. The syngas is treated and fed to a Fischer-Tropsch process. The excess heat produces steam that is used to pyrolize biomass. The biomass produces char, gas, and vapor. The char and gas are recovered, and the vapor is condensed to produce bio-oil.

The proposed plant has a capacity of 1100 tons of biomass (550 dry tons) per day. I assumed an operating factor of 0.9 The plant could be operational within five years, …

Characterization Of Macromolecular Structure Of Pyrolysis Products From A Colorado Green River Oil Shale, James L. Hillier, Thomas H. Fletcher, Mark S. Solum, Ronald J. Pugmire

Faculty Publications

Volatile products from an oil shale from the Colorado Green River formation were studied by several methods. The oil shale was demineralized, and the resulting kerogen was also chemically analyzed. Both the oil shale and the demineralized kerogen were pyrolyzed at 10 K/min, and the pyrolysis products (light gas, tar, and char) were analyzed using 13C NMR, XPS, GC/MS, and FTIR. Low temperature ashing was performed in order to compare pyrolysis yields of oil shale and demineralized kerogen on a dry ash-free basis. Volatile yields of approximately 75% were achieved in an oil shale retort and 79% in the kerogen …

Prediction Of Sawdust Pyrolysis Yields From A Flat-Flame Burner Using The Cpd Model, Aaron D. Lewis, Thomas H. Fletcher

Faculty Publications

High heating rate pyrolysis experiments were performed on a softwood sawdust in a flat-flame burner reactor at temperatures from 1163 to 1433 K with particle residence times ranging from 23 to 102 ms at atmospheric pressure. Volatile yields of the 45−75 μm sawdust were measured and are believed to be similar to those that would occur in an industrial entrained-flow combustor or gasifier. A refractory tar yield near 1.5 wt % (dry, ash-free) was measured. A high percentage of the fully pyrolyzed sawdust char was spherical, having lost the original sawdust structure. It is suggested that the morphology of sawdust …

An Experimental Investigation Of The Role Of Small Hydrocarbons And Combustion-Generated Nanoparticles On The Formation And Growth Reactions Of Polycyclic Aromatic Hydrocarbons During The Pyrolysis Of A Model-Fuel And Hydrocarbon Gases, Nimesh Bharat Poddar

LSU Doctoral Dissertations

Polycyclic aromatic hydrocarbons (PAH) are an important class of environmental pollutants formed during fuel combustion or pyrolysis. Therefore, an experimental study has been undertaken to better understand the formation and growth pathways of PAH.

To investigate the efficacy of C₃ species as PAH growth agents in the context of solid fuels, pyrolysis experiments have been performed in an isothermal quartz flow reactor in the temperature range of 700–1000 °C and a fixed residence time of 0.3 s. Experiments are performed with the C₃ hydrocarbon, propyne; with catechol (ortho-dihydroxybenzene), a model-fuel representative of aromatic moieties in coal …

Prediction Of Tar And Light Gas During Pyrolysis Of Black Liquor And Biomass, Thomas H. Fletcher, Harland R. Pond, Jarom Webster, Judson Wooters, Larry L. Baxter

Faculty Publications

A generalized model for describing the pyrolysis behavior of low-grade fuels is being developed for incorporation into larger combustion simulation models. Light gas and tar yields from black liquor or biomass pyrolysis can be predicted using the chemical percolation devolatilization (CPD) model originally developed for coal. The initial approach is to measure the average chemical structures in a black liquor sample using 13C NMR spectroscopy. These chemical structures are then used in pyrolysis model predictions. With few changes from the coal-derived kinetic parameters, the model describes the organic pyrolysis behavior of black liquor samples obtained in a nitrogen-purged furnace. It …

Coal Swelling Model For Pressurized High Particle Heating Rate Pyrolysis Applications, Randy C. Shurtz, Joseph W. Hogge, Kade C. Fowers, Gregory S. Sorensen, Thomas H. Fletcher

Faculty Publications

A model was previously developed to describe the decrease in swelling during coal pyrolysis at atmospheric pressure when maximum particle heating rates increase from 10⁴ K/s to 10⁵ K/s. That model included effects of coal type using chemical structure properties. This paper presents results of new experiments to study the effects of elevated pressure and high heating rates on coal pyrolysis. A pressurized flat-flame burner (PFFB) was designed and built to conduct these studies. The pyrolysis experiments reported in this paper were conducted at particle heating rates of ∼105 K/s and maximum gas temperatures of 1700 to 1900 …

Effects Of Pressure On The Properties Of Coal Char Under Gasification Conditions At High Initial Heating Rates, Randy C. Shurtz

Theses and Dissertations

The effects of elevated pressure and high heating rates on coal pyrolysis and gasification were investigated. A high-pressure flat-flame burner (HPFFB) was designed and built to conduct these studies. The HPFFB was designed to provide an environment with laminar, dispersed entrained flow, with particle heating rates of ~10^5 K/s, pressures of up to 15 atm, and gas temperatures of up to 2000 K. Residence times were varied from 30 to 700 ms in this study. Pyrolysis experiments were conducted at particle heating rates of ~10^5 K/s and maximum gas temperatures of ~1700 K at pressures of 1 to 15 atm. …

Pyrolysis Kinetics And Chemical Structure Considerations Of A Green River Oil Shale And Its Derivatives, James L. Hillier

Theses and Dissertations

This work had the objective of determining both the kinetic parameters for the pyrolysis of oil shale and kerogen as well as using analytical techniques coupled with pyrolysis to shed light on the structure of a specific Green River oil shale. Because of the problems with linearized methods and disagreement among literature values and methods, a new method was developed tofit kinetic parameters to non linearized data. The method was demonstrated to determine the "correct" answer for mathematically generated data within a few percent error and was shown to have a lower sum squared error than the linearized methods. The …

Pyrolysis Kinetics Of A Green River Oil Shale Using A Pressurized Tga, James L. Hillier, Thomas H. Fletcher

Faculty Publications

Crushed samples of Green River Oil Shale and its kerogen extract were pyrolyzed at heating rates from 1 to 10 K/min at pressures of 1 and 40 bar and temperatures up to 1000 C. Two to four mass release peaks were observed with the major two corresponding to kerogen pyrolysis and carbonate decomposition. The transient pyrolysis data were fit with a first-order model and a Distributed Activation Energy Model (DAEM). An F-test was used to determine confidence regions and compare the kinetic parameters among the oil shale and demineralized samples, between the two pressure levels, and between the models. The …

Coal Swelling Model For High Heating Rate Pyrolysis Applications, Randy C. Shurtz, Kolbein K. Kolste, Thomas H. Fletcher

Faculty Publications

Thermal swelling of coal during pyrolysis strongly influences combustion and gasification rates. Coal swelling is known to vary strongly with coal rank, heating rate, and total pressure. New experiments confirm and clarify previous observations that maximum swelling occurs for high-rank bituminous coals at heating rates slightly below 10⁴ K/s. Advanced swelling models based on bubble physics yield good qualitative trends at low heating rates, but they fail to predict observed decreases in coal swelling as particle heating rates increase beyond 10⁴ K/s. An empirical swelling correlation for computational fluid dynamics (CFD) applications that correctly describes experimentally observed trends …

Characteristics And Kinetics Of Biomass Pylolysis In A Micro Fluidized Bed Reactor, Guangwen Xu, Shiqiu Gao, Jian Yu, Qiang Li, Jianhong Zhu, Zhengkang Duan

The 13th International Conference on Fluidization - New Paradigm in Fluidization Engineering

A Micro Fluidized Bed Reactor (MFBR) was developed to enable on-line pulse feeding and isothermal differential reaction of particle reactant. Application of the MFBR to biomass pyrolysis demonstrated that the resulting globe kinetics parameters were 11.77 kJ/mol and 1.45 s-1 on the gas release characteristics, respectively.

Investigation Of Nitrogen Release During Coal Pyrolysis In An Oxy-Fuel Combustion Process, John M. Sowa, Kolbein K. Kolste, Thomas H. Fletcher

Faculty Publications

Three coals were studied in a flat flame burner (FFB) to determine nitrogen release during pyrolysis as a function of the temperature from 1600 to 1900 K in an oxy-fuel environment. The oxy-fuel environment was created by replacing the background N2 with CO2 in the FFB experiments. Both types of experiments were conducted under fuel-rich conditions, with no O2 present in the postflame gases. The oxy-fuel results were compared to previous results from FFB experiments in a N2 atmosphere. A bituminous coal showed no difference in mass and nitrogen release between the two environments. The sub-bituminous coal exhibited higher mass …

Improved Method For The Determination Of Kinetic Parameters From Non-Isothermal Thermogravimetric Analysis (Tga) Data, Thomas H. Fletcher, James L. Hillier, Trent Bezzant

Faculty Publications

Thermogravimetric analysis (TGA) at a constant heating rate is a popular technique for characterizing reaction behavior. Determination of kinetic coefficients from suchTGAdata has given rise to a large range of reported activation energies for similar samples. In general, rate coefficients are determined using either a linearized integral method or a derivative method. A new method incorporating several well-known techniques is presented that avoids the problems with the linearized techniques as they are generally used. This paper compares results from the new method with results using either the integral or derivative method. Mathematically generated data were used with known kinetic parameters …

Studies Of Coal Nitrogen Release Chemistry For Oxyfuel Combustion And Chemical Additives, John M. Sowa

Theses and Dissertations

Pollution is one of the greatest concerns with pulverized coal combustion. With tightening standards on pollution emissions, more information is needed to create better design models. Burner modifications are the most efficient changes that can be made to assure sufficient carbon burnout and low NOx emissions. Experiments were performed in the BYU Flat Flame Burner (FFB) lab, operating under fuel rich conditions for pyrolysis experiments and fuel lean conditions for char oxidation experiments. Effects of temperature, coal rank, residence time, and post flame oxygen content on mass release, nitrogen release, and reactivity were examined. Elemental and Inductively coupled plasma (ICP) …

The Effects Of Inorganic Solids And Certain Gases On The Thermal Decomposition Of Catechol, Jerome Apilan Robles

LSU Doctoral Dissertations

In order to investigate the effects of calcium carbonate and iron oxide on the thermal decomposition of solid fuels, we have constructed an isothermal flow reactor to perform experiments on the model compound catechol (ortho-dihydroxybenzene), a phenol-type compound representative of coal, wood and biomass. Calcium carbonate and iron oxide are inorganic components of coal and wood, which have demonstrated catalytic properties in thermal reactions and are commercially used to enhance the conversion of solid fuels. In this study, the effects of the inorganic solids on pyrolysis and combustion are conducted through identification and quantification of the products formed after subjecting …

Fuel Composition Analysis Of Endothermically Heated Jp-8 Fuel For Use In A Pulse Detonation Engine, Eric A. Nagley

Theses and Dissertations

Waste heat from a pulse detonation engine (PDE) was extracted via zeolite catalyst coated concentric tube-counter flow heat exchangers to produce supercritical pyrolytic conditions for JP-8 fuel. A sampling system and method were developed that enabled samples of reacted fuel to be extracted during steady state operation. Samples were taken over a range of heat exchanger exit temperatures from 820 K (1016° F) to 940 K (1232° F). Offline analysis of liquid and vapor fuel samples indicated fuel decomposition via typical pyrolytic reaction pathways. The liquid analysis showed conversion of parent fuel components with formation of unsaturates (aromatics and alkenes) …

Multi-Wall Carbon Nanotubes Obtained By Fluidized Bed Pyrolysis Of Virgin Or Recycled Plastics, Umberto Arena, Maria Laura Mastellone

The 12th International Conference on Fluidization - New Horizons in Fluidization Engineering

A new technique for a continuous, mass production of high-quality multi-wall carbon nanotubes (MWCNTs), based on fluidized bed pyrolysis of polymers (virgin or recycled polyolefins and recycled polyethylene terephtalate), is described in detail. The study investigates the role of interactions between the bed material and the polymer particles injected into the reactor as well as that of the reactor temperature. Results are reported in terms of yield and quality of obtained MWCNTs, all characterized by thermogravimetrical analysis and SEM microscopy. The production of MWCNTs, in a relatively large quantity and at a low cost, is demonstrated as technically feasible.

Fast Pyrolysis Of Biomass In A Circulating Fluidised Bed, Manon Van De Velden, Xianfeng Fan, Andy Ingram, Jan Baeyens

The 12th International Conference on Fluidization - New Horizons in Fluidization Engineering

CFB biomass pyrolysis produces mostly bio-oil. Reaction rates are fast (k > 0.5 s-1). Yields exceed 60 wt% of bio-oil at 500 °C and at a residence time for oil and char t < 2.5 s. as achieved in plug flow CFB-mode, shown by PEPT to occur at U > (Utr + 1) m/s and G > 200 kg/m² s.

Development Of Ruthenium-Based Catalysts For Oxygen Reduction Reaction, Lingyun Liu, Hansung Kim, Jong-Won Lee, Branko N. Popov

Faculty Publications

A process was developed to synthesize ruthenium-based chelate (RuN_x) electrocatalysts for the oxygen reduction reaction, using RuCl₃ and propylene diammine as the Ru and N precursors, respectively. High-temperature pyrolysis has a critical role in the formation of the catalytic Ru–N sites for oxygen reduction. The RuN_x catalyst modified in the presence of nitrogen-containing organic exhibited comparable catalytic activity and selectivity for oxygen reduction to the carbon-supported Pt catalyst in acidic media. The catalyst generates less than 2% hydrogen peroxide during oxygen reduction.

Generation Of Biomarkers From Anthrax Spores By Catalysis And Analytical Pyrolysis, Phillip R. Smith

Theses and Dissertations

Anthrax spores, in weaponized form, are dangerous biological warfare agents. Handheld technology for the rapid detection of anthrax is greatly needed to improve national security. Methods to detect anthrax spores are diverse, with most taking at least an hour for positive identification. A viable option for rapid detection is analytical pyrolysis (AP), which produces chemicals containing taxonomical information (biomarkers). AP methods are reviewed and critically analyzed to show that reproducible detection of anthrax spores in a rapid manner (< 5 min) with a handheld device is not currently possible. A promising alternative to AP is the use of a catalyst to produce biomarkers from anthrax spores with improved selectivity and reproducibility. Catalytic materials having promise for this include platinum, nickel, and superacids. Experiments evaluating several of these materials are described. A biomarker mass spectral library was created, based on information available in the scientific literature, to facilitate analysis and identification of the biomarkers produced experimentally. The RAMFAC algorithm was used to deconvolute chromatographic peaks to produce clean mass spectra and match them against entries in the biomarker library. While the library is not complete, its use with the RAMFAC algorithm enabled detection of many important biomarkers in experiments involving catalytic breakdown of anthrax spores. Experimental results from preliminary tests of several catalysts are presented and discussed. Addition of catalysts in the form of platinum nanoclusters and superacids to bacterial spores in a commercial pyrolyzer effected an increase in the amount of biomarkers produced at mild conditions over traditional pyrolysis methods. Electroformed nickel mesh, on the other hand, demonstrated low catalytic activity for the production of biomarkers, likely due to poor contact of the spores with the mesh. Biomarkers similar to those published in the literature were observed, including dipicolinic acid, picolinic acid, propionamide, acetamide, diketopiperazines, fatty acids, furfuryl alcohol, and DNA bases. A statistically designed factorial study was used to determine the importance of temperature, spore loading, and nanocluster loading on the production of three important biomarkers. The relative importance of these variables differs for each of the three important biomarkers, suggesting they are produced by different reaction mechanisms.

Effects Of Pressure On Coal Pyrolysis And Char Morphology, Dong Zeng, Thomas H. Fletcher

Faculty Publications

A better understanding of high-pressure coal pyrolysis is needed to design advanced coal gasification combined-cycle systems. High-temperature, high-heating-rate, and high-pressure pyrolysis experiments were conducted on three bituminous coals and a lignite, to more fully understand the effects of pressure on resultant char properties. A flat-flame burner was designed and used inside a high-pressure drop-tube reactor to provide a high-temperature, high-heatingrate environment that is representative of industrial processes. Chars were prepared at four different pressures, ranging from 0.85 atm to 15 atm. The measured total volatiles yields compared well with predictions of the Chemical Percolation Devolatilization (CPD) model. The physical properties …

High-Pressure Coal Pyrolysis In A Drop Tube Furnace, Koichi Matsuoka, Zhi-Xin Ma, Hiroyuki Akiho, Zhan-Guo Zhang, Akira Tomita, Thomas H. Fletcher, Marek A. Wojtowicz, Stephen Niksa

Faculty Publications

To obtain useful and reliable pyrolysis data under high pressures, continuous pyrolysis experiments were carried out using a drop tube furnace. To ascertain the reliability of data, a mass balance during pyrolysis was carefully checked. The pyrolysis data obtained in this equipment was compared with previous results, and it was found that the weight loss observed in the drop tube furnace was somewhat larger than those obtained with other apparatuses. The experimental results were compared with those predicted by three pyrolysis models. Although discrepancies between predictions and experimental results were observed under a certain condition, the agreement between the experimental …

Simulation Of Coal Pyrolysis In Plasma Jet By Cpd Model, Yajun Tian, Kechang Xie, Suyu Zhu, Thomas H. Fletcher

Faculty Publications

Reaction of coal in a plasma jet is complex and extremely rapid, and acetylene and carbon monoxide are the main products in the pyrolysis gas. Coal pyrolysis is assumed as the first step reaction when coal is injected into hot plasma jet with initial average temperature of 3700 K. Chemical percolation devolatilization (CPD) is employed first to simulate this procedure in mechanism. The calculation results indicate coal pyrolysis rate in plasma jet is very fast and the retention time of coal staying in reactor is only several milliseconds. Comparing the calculation with experiment result, it was concluded that the CPD …

Solid-State 13c Nmr Characterization Of Matched Tars And Chars From Rapid Coal Devolatilization, Steven T. Perry, Eric M. Hambly, Thomas H. Fletcher, Mark S. Solum, Ronald J. Pugmire

Faculty Publications

Matched tar/char sets were prepared by pyrolysis of a lignite and a bituminous coal in two entrained flow reactors at temperatures between 900 K and 1650 K and heating rates of 10⁴–10⁵ K/s. Detailed chemical structural characterization of these tars and chars was performed using elemental analysis and solid-state ¹³C NMR. This is the first set of detailed solid-state ¹³C nuclear magnetic resonance (NMR) data on coal tar samples. The average aromatic cluster sizes of the primary tars from these experiments are quite similar to those of their parent coals, confirming an assumption often made …

Modeling Nitrogen Evolution During Coal Pyrolysis Based On A Global Free-Radical Mechanism, Steven T. Perry, Thomas H. Fletcher

Faculty Publications

A global free-radical mechanism and an associated rate equation for the evolution of light gas nitrogen during coal devolatilization are presented. The light gas nitrogen rate equation was used to modify an existing nitrogen model so that only a network devolatilization model and coal-specific chemical structural input data are required to adequately predict light gas nitrogen release at a variety of pyrolysis conditions. Model predictions show good agreement with nitrogen release data from pyrolysis of coals of rank from lignite to low volatile bituminous at heating rates from 0.5 to 10⁵ K/s, temperatures as high as 2300 K, and …

Modeling Nitrogen Release During Devolatilization On The Basis Of Chemical Structure Of Coal, Dominic Genetti, Thomas H. Fletcher

Faculty Publications

A model that predicts the amount and distribution between tar and light gas of nitrogen released during devolatilization has been developed and incorporated into the chemical percolation devolatilization (CPD) model. This work represents the first volatile nitrogen release model developed on the basis of ¹³C NMR measurements of coal structure. This work also represents the first volatile nitrogen release model evaluated by comparing model predictions with chemical structural features of the char (determined by ¹³C NMR spectral analyses). The model is limited to nitrogen release during primary pyrolysis, and assumes that all light-gas nitrogen is HCN. Model predictions …

New Technologies For Thermal Disposal Of Sewage Sludge, T Ogada

Tanzania Journal of Engineering and Technology (TJET)

The traditional methods for the disposal of sewage sludge are landfilling, recycling as fertilisers in agricultural lands, dumping into sea and incineration. In thc recent past, Sludge incineration has been rapidly gaining ground duc to environmental constraints facing the Other methods. However, the cost of pollution control during sewage sludge incineration is currently very high due to the expensive flue gas treatment facility required. Futhermore, large quantity Of ash is produced which is highly contaminated with heavy metals and must be disposed off in special landfilling sites in order to avoid ground water pollution. To reduce the cost Of pollution …

Nitrogen Transformations In Coal During Pyrolysis, Simon R. Kelemen, Martin L. Gorbaty, P J. Kwiatek, Thomas H. Fletcher, Mathew Watt, Mark S. Solum, Ronald J. Pugmire

Faculty Publications

X-ray photoelectron spectroscopy (XPS) was used to identify and quantify the changes in organically bound nitrogen forms present in the tars and chars of coals after pyrolysis. For fresh coal, pyrrolic nitrogen is the most abundant form of organically bound nitrogen, followed by pyridinic, quaternary, and amino types. Some of the quaternary nitrogen species initially present in coal are lost upon mild pyrolysis, prior to hydrocarbon devolatilization. These quaternary species are attributed to pyridinic or basic nitrogen species associated with hydroxyl groups from carboxylic acids or phenols. A portion of the quaternary nitrogen species is lost at the very earliest …

Effects Of Pyrolysis Heating Rate On Intrinsic Reactivities Of Coal Chars, Thomas K. Gale, Calvin H. Bartholomew, Thomas H. Fletcher

Faculty Publications

The main objective of this work was to determine the effects of pyrolysis heating rate on intrinsic O₂ reactivity of coal chars. Relationships of intrinsic reactivity to other pyrolysis conditions and char physical and chemical structure were also investigated, and empirical correlations were obtained. Two different entrained flow reactors (a flat flame methane/air burner and a drop tube reactor) were used to prepare chars under a variety of different pyrolysis conditions at maximum particle temperatures and heating rates of 840-1627 K and 10⁴ to 2x10⁵ K/s, respectively. Intrinsic reactivities of a lignite and two bituminous coal chars …