Steam gasification of bagasse: Effect of heating rate

Bagasse residue is a potential feedstock for steam gasification, but knowledge of this technology is still small and fragmented. Heating rate is of the most important factors influencing the gasification process. However, this parameter has not yet been fully investigated. In this study, the characteristics of bagasse and its chars were identified, and the effect of heating rate on steam gasification kinetics was studied. Bagasse contained little ash content, comparable to woody biomass, which is beneficial for thermochemical conversion processes. The bagasse char had a high heating value, comparable to coal. Effect of a small change in heating rate from 5 to 15 °Cmin-1 was not observed, while a significant increase from 15 to 1800 °Cmin-1 had a considerable effect on steam gasification kinetics. A char produced at a high heating rate increased gasification kinetics by 1.35 times compared to a char produced at a low heating rate. Results and data produced could be useful for the conception of new gasifiers using bagasse, such as staged-gasifiers in which the char production zone is separated from the gasification zone

Gasification of Pine Wood Chips with Air-Steam in Fluidized Bed

Tato práce studovala vliv použití vzduchu a páry jako zplynovacího činidla ve zkapalňovacím generátoru plynu na vlastnosti vyprodukovaného plynu (oxid uhelnatý, vodík, obsah dehtu a nízká výhřevnost). Tato studie byla založena na experimentech které byly provedeny ve fluidním generátoru plynu Biofluid 100 v laboratoři Energetického ústavu technologické univerzity Brno s použitím páry jako zplynovacího činidla a borovicového dřeva jako výchozí suroviny. Cílem této dizertační práce je stanovit nejlepší provozní parametry systému při užití vodní páry a vzduchu ve zplynovacím zařízení biofluid 100, při kterých se dosáhne nejvyšší kvality plynu. K dosažení tohoto cíle bylo provedeno mnoho experimentů studujících účinky teploty reaktoru(T101), poměru páry a biomasy (S/B) poměru páry a vzduchu (S/A), teploty dodávané páry (Tf1), ekvivalentního poměru ER,ve složení vyprodukovaném plynu, výhřevnost, výtěžnost plynu, efektivnost přeměny uhlíku a účinnost zplynovače. Výsledky experimentů ukázaly, že zvýšení teploty reaktoru vede ke zvýšení obsahu vodíku a oxidu uhelnatého, výhřevnosti, výtěžnosti plynu, efektivnosti přeměny uhlíku, efektivnosti zplynovače a ke snížení obsahu dehtu. Příliš vysoká teplota reaktoru ale snižuje výhřevnost plynu. Dodáváním páry se zvýšila kvalita plynu, vyšší H_2,LHV a nižší obsah dehtu. Přesto ale nadměrné množství páry snižuje zplyňovací teplotu a tím i kvalitu plynu. Poměr páry a biomasy při kterém se dosáhne nejlepší kvality plynu se zvýší s teplotou reaktoru. Bylo zjištěno, že kdykoli byla teplota páry (Tf1) vyšší, byl plyn více kvalitní, ale zvyšování teploty páry také zvyšuje ekonomické náklady na vyprodukovaný plyn což se při masové produkci plynu musí brát v úvahu. Efekt ekvivalentního poměru ER, byl studován postupným zvyšováním, bylo zjištěno, že nejlepší ekvivalentní poměr pro dosažení nejvyšší kvality plynu byl kolem 0.29, při ER > 0.29 byl obsah hořlavého plynu snížen a to vedlo ke snížení kvality plynu. Obsah dehtu se snižuje jak zvýšením teploty reaktoru tak poměrem páry k biomase. Podle výsledků experimentů a diskuze, bylo zjištěno, že při použití směsi páry a vzduchu se kvalita plynu zvýší, parametry pro dosažení nejvyšší kvality vyprodukovaného plynu při experimentálních podmínkách jsou: T101 =829 S/B=0.67((kg steam)/(kg biomass)) ,S/A=0.67((kg steam)/(kg air)) , ER= 0.29 and a Tf1 je nejvyšší možná teplota,při které se vodík zvýší z 10.48 na 19,68% a výhřevnost z 3.99 na 5.52(MJ/m^3 ) a obsah dehtu z 1964(mg/m^3 ) na 1046(mg/m^3 ) zvýšením z 0 na 0.67 při T101=829 .This work has been studied the impact of using of air-steam as gasification agent in fluidized bed gasifier on produced gas properties (Carbon monoxide, Hydrogen,tar content and low heating value . This study has been based on the experiments which have been done in fluidized bed gasifier called Biofluid 100, where exists in lab of the Institute of Power Engineering, Brno University of Technology, by using air-steam as agent of gasifier and pine wood chips as the feedstock. The aim of this thesis is to determine the best operating parameters of system air- steam gasification in biofloud 100 which achive the best gas quality. To accomplish this task , many experiments have been performed to studied the effect of reactor temperature(T101), steam to biomass ratio (S/B), steam to air ratio (S/A) , temperature of provided steam (Tf1) and equivalence ratio (ER)on produced gas composition , low heating value(LHV),gas yield ,carbon conversion efficiency and gasifier efficiency. The results of experiments have been shown , that the increase the temperature of reactor (T101) lead to increase hydrogen content , carbon monoxide content ,low heating value,gas yield , carbon conversion efficiency ,gasifier efficiency and reduce the tar content, but too high reactor temperature lowered low heating value of gas. By providing steam,the gas quality (H_2,LHVand tar content) has been imroved ,however excessive steam has been lowered gasification temperature and thus reduced gas quality. The ratio of steam to biomass, which achieve the best gas quality has been increased by reactor temperature. It has been found, that whenever steam temperature (Tf1)was higher , whenever the gas produced more quality, but the increase of steam temperature will increase the economic cost of the product gas,which must take into account when gas production widely. The effect of equivalence ratio(ER) has been studied with increase S/B , it has been found that the best value of equivalence ratio was around 0.29 which achieved the best quality of produced gas , where when ER > 0.29 the combustible gases content have been decreased so it led to lower the gas quality . Tar content decreases by increasing each of reactor temperature (T101) and steam to biomass ratio . According to the results of the experiments and discussion, it has been found, that by using the mixture of steam and air ,the gas quality will be improved ,and the parameters, which will achieve the best quality of the produced gas at experimental conditions are: T101 =829 S/B=0.67((kg steam)/(kg biomass)) ,S/A=0.57((kg steam)/(kg air)) , ER= 0.29 and Tf1 is the highest possible temperature, where hydrogen increased from 10.48 to 19,68 % and Low heating value from 3.99 to 5.52(MJ/m^3 ) and tar decreased from 1964 to 1046 (mg/m^3 ) by increasing S/B from 0 to 0.67 at T101=829 .

Effect of temperature and steam to biomass ratio on NO and SO2 formation in palm kernel shell catalytic steam gasification with in-situ CO2 adsorption

No abstract available

Biomass steam gasification in fluidized bed of inert or catalytic particles: Comparison between experimental results and thermodynamic equilibrium predictions

In order to improve the understanding of biomass gasification in a bed fluidized by steam, the thermochemical equilibrium of the reactive system was studied. The equilibrium results were compared to LGC experimental results, obtained by the gasification of oak and fir in a laboratory-scale fluidized bed of different catalysts: sand, alumina, and alumina impregnated with nickel. The research was completed by a study of the influence on the equilibrium of additional parameters such as the quantity of steam, the pressure or the kind of biomass. Those results of simulation may be used for evaluating the limits of actual reactors.The following conclusion may be drawn from all the results: The thermodynamic equilibrium state calculated is far away from the experimental results obtained on sand particles. The steam to biomass ratio, between 0.4 and 1 kgsteam/kgdry biomass, has a strong influence on the gas mixture composition. The temperature increase and the use of catalyst allow producing a gas mixture with a high content of hydrogen and carbon monoxide. The H2:CO ratio may reach values greater than 3. The use of catalyst allows the system to get closer from the equilibrium, especially for the nickel based catalyst

Pyrolysis/gasification of cellulose, hemicellulose and lignin for hydrogen production in the presence of various nickel-based catalysts

Cellulose, hemicellulose and lignin are the main components of biomass. This work presents research into the pyrolysis/gasification of all three main components of biomass, in order to evaluate and compare their hydrogen production and also understand their gasification processes. A fixed bed, two-stage reaction system has been used employing various nickel-based catalysts. Gas concentration (CO, H, CO, CO and CH ) was analysed for the produced non-condensed gases. Oil byproducts were analysed by gas chromatography/mass spectrometry (GC/MS). Various techniques such as X-Ray Diffraction (XRD), scanning electron microscopy (SEM) coupled to an energy dispersive X-ray spectroscopy (EDXS), temperature- programmed oxidation (TPO) were applied to characterize the fresh or reacted catalysts. The experimental results show that the lignin sample generates the highest residue fraction (52.0 wt.%) among the three biomass components. When NiAZnAAl (1:1) catalyst was used in the gasification process, gas yield was increased from 62.4 to 68.2 wt.% for cellulose, and from 25.2 to 50.0 wt.% for the pyrolysis/gasification of lignin. Hydrogen production was increased from 7.0 to 18.7 (m mol g sample) when the NiAZnAAl (1:1) catalyst was introduced in the pyrolysis/gasification of cellulose. Among the investigated catalysts, NiACaAAl (1:1) was found to be the most effective for hydrogen production from cellulose pyrolysis/gasification

Economic analysis and optimization for bio-hydrogen production from oil palm waste via steam gasification

Biomass steam gasification with in-situ carbon dioxide capture using CaO exhibits good prospects for the production of hydrogen rich gas. In Malaysia, due to abundance of palm waste, it is a good candidate to be used as a feedstock for hydrogen production. The present work focuses on the mathematical modeling of detailed economic analysis and cost minimization of the flowsheet design for hydrogen production from palm waste using MATLAB. The influence of the operating parameters on the economics is performed. It is predicted that hydrogen cost decreasing by increasing both temperature and steam/biomass ratio. Meanwhile, the hydrogen cost increases when increasing sorbent/biomass ratio. Cost minimization solves to give optimum cost of 1.9105 USD/kg with hydrogen purity, hydrogen yield, hydrogen efficiency and thermodynamic efficiency are 79.9 mol%, 17.97 g/hr, 81.47% and 79.85% respectively. The results indicate that this system has the potential to offer low production cost for hydrogen production from palm waste

Innovative aspects of underground coal gasification technology in mine conditions

Purpose. Development of innovative approaches in technological and technical solutions improvement for coal seam gasification. Methods. Carrying-out of native and world experience in the coal reserves development by underground gasification technology analysis, analytical studies on the heat and mass balance gasification process parameters determining and determination of the rock massif stress-deformed state around the gas gasifiers, and its technical and economic indicators operation. Findings. The analytical calculations of the rocks stress-deformed state for the Western Donbas mines conditions have revealed that the maximum length of the gasification pillar should not be more than 580 m. The innovative technological schemes of gas gasifiers sites preparation work are proposed in two constructions: with roses and drill injected blast activators. The energy indicators of the gas gasifiers work, the period of release into the gasification mode during reverse operations and fuel gases discharge during different combustion face advance and the injected blast composition are determined. Introduction of gas gasifiers’ constructions with drill injected blast activators are recommended for the numerous advantages. Originality. The dependence of the gasification pillar length change on the technical and economic parameters of the gasification station operation was established; the dependence of the gasification operation on the gasification mode and exhaust gases discharge, depending on the injected blast composition and the rate of the combustion face advance. Practical implications. The rational parameters of bed preparation at mine gasification, as well as energy and technological parameters of this process are substantiated. New technological schemes for coal reserves working out with gasification have been developed, which will allow additionally to use non-commercial and abandoned mine reserves and extend the mining enterprises duration.Мета. Розробка інноваційних підходів до удосконалення технологічних та технічних рішень при шахтній газифікації вугілля. Методика. Проведення аналізу вітчизняного та світового досвіду з розробки вугільних запасів технологією підземної газифікації, аналітичні дослідження з визначення параметрів матеріально-теплового балансу процесу газифікації, напружено-деформованого стану гірського масиву навколо шахтних газогенераторів та визначення техніко-економічних показників їх роботи. Результати. Аналітичними розрахунками напружено-деформованого стану порід для умов шахт Західного Донбасу встановлено, що максимальна довжина стовпа газифікації повинна складати не більше 580 м. Запропоновані інноваційні технологічні схеми підготовки ділянки пласта шахтних газогенераторів у двох конструкціях: з перфорованими насадками та з перфорованим активатором дуття. Визначені енергетичні показники роботи шахтних газогенераторів, термін виходу у режим газифікації при здійснені реверсних робіт та виходу паливних газів при різному посуванні вогневого вибою та складу дуття. Рекомендовано за численними перевагами впровадження конструкцій шахтних газогенераторів з перфорованим активатором. Наукова новизна. Встановлено залежність зміни довжини стовпа шахтного газогенератора від техніко-економічних показників роботи станції газифікації; залежності виходу шахтного газогенератора у режим газифікації та виходу генераторних газів залежно від складу дуття та швидкості посування вогневого вибою. Практична значимість. Обґрунтовано раціональні параметри підготовки вугільного пласта при шахтній газифікації, а також енергетичні та технологічні показники цього процесу. Розроблено нові технологічні схеми відпрацювання запасів вугілля шахтною газифікацією, що дозволить додатково залучити забалансові та залишені у межах шахтних полів запаси вугілля та подовжити термін існування гірничих підприємств.Цель. Разработка инновационных подходов к совершенствованию технологических и технических решений при шахтной газификации угля. Методика. Проведение анализа отечественного и мирового опыта по разработке угольных запасов технологией подземной газификации, аналитические исследования по определению параметров материально-теплового баланса процесса газификации, напряженно-деформированного состояния горного массива вокруг шахтных газогенераторов и определение технико-экономических показателей их работы. Результаты. Аналитическими расчетами напряженно-деформированного состояния пород для условий шахт Западного Донбасса установлено, что максимальная длина столба газификации должна составлять не более 580 м. Предложенные инновационные технологические схемы подготовки участка пласта шахтных газогенераторов в двух конструкциях: с перфорированными насадками и с перфорированным активатором дутья. Определены энергетические показатели работы шахтных газогенераторов, срок выхода в режим газификации при осуществлении реверсных работ и выхода топливных газов при различном подвигании огневого забоя и состава дутья. Рекомендовано по многочисленным преимуществам внедрение конструкций шахтных газогенераторов с перфорированным активатором. Научная новизна. Установлена зависимость изменения длины столба шахтного газогенератора от технико-экономических показателей работы станции газификации; зависимости выхода шахтного газогенератора в режим газификации и выхода генераторных газов в зависимости от состава дутья и скорости подвигания огневого забоя. Практическая значимость. Обоснованы рациональные параметры подготовки угольного пласта при шахтной газификации, а также энергетические и технологические показатели данного процесса. Разработаны новые технологические схемы отработки запасов угля шахтной газификацией, что позволит дополнительно вовлечь забалансовые и оставленные в пределах шахтных полей запасы угля и продлить срок существования горных предприятий.This work was supported by the Ministry of Education and Science of Ukraine, grants No.0116U008041 and No.0117U001127

Influence of the catalyst support on the steam reforming performance of toluene as tar model compound

The large amount of tar produced along with the syngas during biomass gasification is one of the major obstacle for the diffusion of gasifiers at industrial scale. Catalytic cracking and reforming are the most suitable processes for the transformation of tar into lighter gases. The selection of suitable catalysts is a critical step. The catalysts must own high activity and high resistance to deactivation for coke deposition. In this work the effect of two different supports, mayenite and aluminium oxide, on the activity of the nickel was investigated in the steam reforming of toluene that was used as tar model compound. In particular, the performed experimentations aimed to test the mayenite in terms of improvement of resistance to carbon deposition in conditions similar to those of gasification reactors. The obtained results indicate that Ni /mayenite catalyst needs higher temperature to activate and leads to lower value of toluene conversion with respect to Ni / alumina. However, mayenite, which is known from literature to have higher resistance to coke deposition due to the presence of free oxygens in the lattice which oxidize the coke deposited on the catalyst surface showed higher resistance to deactivation especially for low steam to carbon ratios