The rapid increase in energy demand, the extensive use of fossil fuels, and the urgent need to reduce carbon dioxide emissions have raised concerns in the transportation sector, since transportation has been primarily dependent on fossil fuels. Biofuel from biomass can make significant contributions to overcome the expected depletion of fossil fuels and reduce carbon emissions. The availability and wide diversity of biomass resources have made them an attractive and promising source of fuels. Biomass can be converted into biofuel by thermochemical pyrolysis process. Improvements on the pyrolysis process of biomass fuels are needed to obtain a high-quality of bio-oil. Pre-treatment by acid leaching prior to the pyrolysis process is considered to remove Alkali and Alkaline Earth Metal (AAEM) from the biomass, since AAEM adversely affect the catalytic pyrolysis process. Information about biomass pyrolysis kinetics is also important to evaluate biomass as a feedstock for fuel or chemical production as well as efficient design and control of thermochemical processes. Further, the use of H-ZSM-5 and Al-MCM-41 as a mesoporous and a microporous catalyst has been proved to improve the quality of bio-oil. The influence of a catalyst regeneration on the chemical composition of the upgraded oil is also one of the factors pertaining to the catalytic process.In this study, the catalytic pyrolysis kinetics of lignocellulose biomass with a mixed catalyst of H-ZSM-5 and Al-MCM-41 at different ratios for both, un-leached and leached biomass, is analyzed. The derived activation energies are determined based on the solid-state reaction mechanism. Bench-scale experiments have also been investigated to improve the quality of bio-oil, in terms of Organic Fraction (OF), water content, acidity, favorable fractions, as well as gasoline-range chemicals. The effect of a mixed-catalysts and staged-catalysts consisting of H-ZSM-5 and Al-MCM-41 at different ratios in a lignocellulose biomass pyrolysis has been compared. The ratio of H-ZSM-5 and Al-MCM-41 in the catalyst mixtures for lignocellulose biomass catalytic pyrolysis has also been optimized. Further, the effect of sequential catalyst regenerations of H-ZSM-5 and Al-MCM-41 catalyst mixtures on the obtained catalytic pyrolysis products has been analysed.The bench-scale experiments of lignocellulosic biomass pyrolysis and catalytic pyrolysis were performed using a fixed bed reactor equipped with oil condensers and a gas collection sample bag. The quality of bio-oil produced from the thermal pyrolysis of lignocellulosic biomass, catalytic pyrolysis with single catalyst, catalytic pyrolysis with staged catalyst system, as well as catalytic pyrolysis with mixed catalyst system were studied. Later, the catalyst was regenerated several times and the regenerated catalyst was reloaded in the reactor to proceed with the next run. The composition of the derived upgraded pyrolysis oils in relation to the catalyst regeneration was determined.The results from the acid leaching treatment showed that the optimum leaching process was set to 30 minutes, 30°C and 5 wt.% acetic acid in the leaching liquid. This resulted in 59%, 95%, 99%, and 96% reduction degree of Calcium (Ca), Magnesium (Mg), Potassium or Kalium (K), and Natrium (Na), respectively. The use of the acid leaching process as a treatment prior to catalytic pyrolysis is positive, since it resulted in high devolatilization and reaction rate. For the kinetic studies, the second order (F2) mechanism was able to illustrate the catalytic pyrolysis process, proven by the result that the coefficient of determination (R2) was higher than 0.99, which was high compared to other mechanisms.The bench-scale experiments show that that Al-MCM-41 with H-ZSM-5 in the staged catalyst system enhanced the production of favorable compounds: hydrocarbons, phenols, furans, and alcohols. The favorable compounds yield that boosted 5.25-6.43% of that with single H-ZSM-5 catalyst was produced with H-ZSM-5:Al-MCM-41 mass ratio of 3:1 and 7:1. The pyrolysis and catalysis temperature of 500°C with H-ZSM-5:Al-MCM-41 ratio of 3:1 obtained the optimum quality of bio-oil with 11.08 wt.% of Organic Fraction (OF), 76.20% of favorable fractions, 41.97 wt.% of water content, low TAN of 43.01 mg-KOH/g, high deoxygenation, as well as high gasoline-range production of 97.89%.The catalyst mixture of H-ZSM-5 and Al-MCM-41 with a ratio of 7:1 resulted in a 65.75% deoxygenation degree. An organic-rich bio-oil was obtained with 74.90 wt.% of carbon content, 8 wt.% of hydrogen content, 15 wt.% oxygen content, a 0.39 wt.% water content, and a high heating value of 34.15 MJ/kg. The highest amount of favorable compounds among the studied catalytic experiments was obtained with a value of 95.89%. The significant improvement in the quality of bio-oil with the utilisation of H-ZSM-5 and Al-MCM-41 catalyst mixtures was the rise of favorable compounds in bio-oil.The experiments of sequential catalyst regenerations of H-ZSM-5 and Al-MCM-41 catalyst mixtures show that the catalytic activity decreased as the number of reaction cycles increased, albeit an increase yield of Organic Fraction (OF) and a decrease in water as well as coke yields. The HHV of bio-oils decreased. However, the minimum value of HHV (22.42 MJ/kg) after 6 sequential usage was still higher than the value for the non-catalytic experiment (19.55 MJ/kg). The favorable compounds yield, which includes hydrocarbons, phenols, furans, and alcohol, decreased. The dominant components contributed to the yield of favorable compounds were hydrocarbon aromatics and phenols.

Den snabba ökningen av energibehovet, den omfattande användningen av fossila bränslen och det brådskande behovet av att minska koldioxidutsläppen har väckt oro inom transportsektorn, eftersom transport främst har varit beroende av fossila bränslen. Biobränsle från biomassa kan ge betydande bidrag för att övervinna den förväntade uttömningen av fossila bränslen och för att minska koldioxidutsläppen. Tillgången och den stora mångfalden av biomassaresurser har gjort dem till attraktiva och lovande källor för bränslen. Biomassa kan omvandlas till biobränsle genom användandet av en termokemisk pyrolysprocess.

Förbättringar av pyrolysprocessen av biomassabränslen behövs för att erhålla en högkvalitativ bioolja. En förbehandling med syralakning före pyrolysprocessen anses kunna avlägsna alkalimetaller och alkaliska jordartsmetaller (AAEM) från biomassan, eftersom AAEM negativt påverkar den katalytiska pyrolysprocessen. Information om kinetik vid pyrolys av biomassa är också viktig information för att utvärdera biomassa som råvara för bränsle- eller kemisk produktion samt för en effektiv design och kontroll av termokemiska processer. Vidare har användningen av H-ZSM-5 och Al-MCM-41 som en mesoporös katalysator respektive en mikroporös katalysator visat sig förbättra kvaliteten på bioolja. Påverkan av en katalysatorregenerering på den kemiska sammansättningen av den uppgraderade oljan är också en av de faktorer som är relaterad till den katalytiska processen.

I denna studie analyseras kinetiken för den katalytiska pyrolysen av en lignocellulosbaserad biomassa genom användande av en katalysatorblandning bestående av H-ZSM-5 och Al-MCM-41 för olika förhållanden och för både olakade och urlakade biomassor. De erhållnaa aktiveringsenergierna bestäms baserat på fastfas reaktionsmekanismen. Experiment i bänkskala har också genomförts för att studera hur det är möjligt att förbättra kvaliteten på bioolja med avseende på organisk fraktion (OF), vatteninnehåll, surhet, gynnsamma fraktioner samt kemikalier som är av vikt i bensinprodukter. Effekten av användningen av blandade katalysatorer och iscenesatta katalysatorer bestående av H-ZSM-5 och Al-MCM-41 för olika förhållanden vid pyrolys av en lignocellulosabaserad biomassa har jämförts. Studier av optimering av förhållandet mellan H-ZSM-5 och Al-MCM-41 i katalysatorblandningarna vid en katalytisk pyrolys av lignocellulosabaserad biomassa har också genomförts. Vidare har effekten av sekventiella katalysatorregenereringar av H-ZSM-5 och Al-MCM-41-katalysatorblandningar på de erhållna katalytiska pyrolysprodukterna studerats.

Bänkskalaexperimenten med en lignocellulosabaserad biomassapyrolys och en katalytisk pyrolys utfördes med användning av en reaktor bestående av en fast bädd utrustad med oljekondensatorer och en provpåse för uppsamling av gas. Kvaliteten på biooljan producerad genom användande av en termisk pyrolys av lignocellulosamassa, en katalytisk pyrolys med enstaka katalysatorer, en katalytisk pyrolys med användande av iscensatt katalysatorsystem samt en katalytisk pyrolys med användande av ett blandat katalysatorsystem studerades. Därefter så regenererades katalysatorn flera gånger och den regenererade katalysatorn laddades om i reaktorn för att utföra nästa försök. Dessutom så bestämdes sammansättningen av de härledda uppgraderade pyrolysoljorna i förhållande till katalysatorregenerationen.

Resultaten från syralakningsbehandlingen visade att den optimala urlakningsprocessen erhälls om följade parametrar användes: 30 minuter, 30°C och 5 vikt-% ättiksyra i lakvätskan. Detta resulterade i 59%, 95%, 99% och 96% reduktionsgrader med avseende på kalcium (Ca), magnesium (Mg), kalium (K) och natrium (Na). Användningen av syralakningsprocessen som en behandling före en katalytisk pyrolys gav positiva resultat, eftersom den resulterade i en hög devolatilisering och en hög reaktionshastighet. För de kinetiska studierna kunde en andra ordningens (F2) mekanism användas för att illustrera den katalytiska pyrolysprocessen. Denna slutsats baserades på resultatet att bestämningskoefficienten (R2) var högre än 0,99, vilket var högt jämfört med de andra undersökta mekanismerna.

Experimenten i bänkskala visar att användandet av en kombination av Al-MCM-41 och H-ZSM-5 i det iscensatta katalysatorsystemet förbättrade produktionen av följande gynnsamma föreningar: kolväten, fenoler, furaner och alkoholer. De gynnsamma föreningarna som gav 5,25-6,43% med användande av en enkel H-ZSM-5-katalysator framställdes med ett H-ZSM-5: Al-MCM-41 massförhållande motsvarande 3:1 respektive 7:1. Användande av pyrolys- och katalystemperaturer som var 500°C och ett H-ZSM-5: Al-MCM-41-förhållande som var 3:1 resulterade i en optimal kvalitet på biooljan som innehöll 11,08 vikt-% av en organisk fraktion (OF), 76,20% av gynnsam fraktioner, 41,97 vikt-% vatten, en låg TAN mängd motsvarande 43,01 mg-KOH/g, en hög deoxygenering och en hög bensinproduktion motsvarande 97,89%.

Katalysatorblandningen bestående av H-ZSM-5 och Al-MCM-41 med ett förhållande av 7:1 resulterade i en 65,75% deoxygeneringsgrad. Dessutom så erhölls en organisk rik bioolja erhölls med ett 74,90 vikt-% kolinnehåll, ett 8 vikt-% väteinnehåll, ett 15 vikt-% syreinnehåll, ett 0,39 vikt-% vatteninnehåll och ett högt värmevärde motsvarande 34,15 MJ/kg. Värdet på den högsta mängden gynnsamma föreningar bland de studerade katalytiska experimenten var 95,89%. Den signifikanta förbättringen av kvaliteten av bioolja genom användning av en H-ZSM-5 och Al-MCM-41-katalysatorblandning förklarades med ökningen av förekomsten av gynnsamma föreningar i biooljan.

Experiment med användande av sekventiella katalysatorregenereringar av katalysatorblandningar innehållande H-ZSM-5 och Al-MCM-41 visar att den katalytiska aktiviteten minskade när antalet reaktionscykler ökade, även om utbytet av organisk fraktion ökar och vattenhalten och koksutbytet minskar. HHV av biooljor minskade. Minimivärdet för HHV (22,42 MJ/kg) efter 6 sekventiella användningar var dock fortfarande högre än värdet för experimentet som utfördes utan att använda katalysatorer (19,55 MJ/kg). Dessutom så visade resultaten att utbytet av de gynnsamma föreningarna kolväten, fenoler, furaner och alkohol, minskade. De dominerande komponenterna bidrog till det ökade utbytet av gynnsamma föreningar var kolvätearomater och fenoler.

Nyckelord: Al-MCM-41, lignocellulosa biomassa, H-ZSM-5, kinetisk studie, katalysatorregenerering

Catalyst regeneration is economically attractive, and it saves resources. Thus, it is important to determine the influence of catalyst regeneration on the chemical composition of upgraded oil. The catalyst was regenerated several times, and the regenerated catalyst was reloaded in the reactor to proceed with the next run. The composition of the derived upgraded pyrolysis oils in relation to catalyst regeneration was determined. The results revealed that the catalyst cracking abilities decreased with an increased number of reaction cycles. The opposite trends of the organic fraction and water yields indicated that the deoxygenation process occurred via H2O production. A decrease in the CO and CO2 yields revealed that the deoxygenation in catalytic pyrolysis with a catalyst mixture occurred via decarbonylation, decarboxylation, and dehydration mechanisms. The chemical formula of bio-oil changed from CH0.17O0.91 for a noncatalytic experiment to CH0.14O0.66 for a catalytic pyrolysis experiment after five reaction cycles, which indicated that the oxygen in the bio-oil decreased at the expense of hydrogen. The high heating value (HHV) of bio-oils decreased as the number of reaction cycles increased, albeit the minimum value of 22.41 wt % in the 6th reaction cycle was still higher than the value for the noncatalytic experiment. Compared to the HHVs of diesel fuel and gasoline petrol, the values of the produced bio-oil with catalyst mixtures were still low. The catalyst regained 94% of the surface area for the fresh catalyst, which indicated that the regeneration procedure was effective.

The present work is an attempt to optimize the proportion of H-ZSM-5 and Al-MCM-41 in the catalyst mixtures for lignocellulose biomass catalytic pyrolysis. The H-ZSM-5 proportions of 50.0, 66.7, 75.0, and 87.5 wt.% were examined for the upgrading of biomass pyrolysis vapors in the fixed bed reactor. The catalyst mixture of 87.5 wt.% H-ZSM-5 and 12.5 wt.% Al-MCM-41 was found most effective in this study, giving a 65.75% deoxygenation degree. An organic-rich bio-oil was obtained with 74.90 wt.% of carbon content, 8 wt.% of hydrogen content, 15 wt.% oxygen content, a 0.39 wt.% water content, and a high heating value of 34.15 MJ/kg. The highest amount of desirable compounds among the studied catalytic experiments, which include hydrocarbons, phenols, furans, and alcohols, was obtained with a value of 95.89%. A significant improvement in the quality of bio-oil with the utilization of H-ZSM-5 and Al-MCM-41 catalyst mixtures was the rise of desirable compounds in bio-oil.

Gasification of excavated landfill waste is one of the promising options to improve the added-value chain during remediation of problematic old landfill sites. Steam gasification is considered as a favorable route to convert landfill waste into H-2-rich syngas. Co-gasification of such a poor quality landfill waste with biochar or biomass would be beneficial to enhance the H-2 concentration in the syngas, as well as to improve the gasification performance. In this work, steam co-gasification of landfill waste with biochar or biomass was carried out in a lab-scale reactor. The effect of the fuel blending ratio was investigated by varying the auxiliary fuel content in the range of 15-35 wt%. Moreover, co-gasification tests were carried out at temperatures between 800 and 1000 degrees C. The results indicate that adding either biomass or biochar enhances the H-2 yield, where the latter accounts for the syngas with the highest H-2 concentration. At 800 degrees C, the addition of 35 wt% biochar can enhance the H-2 concentration from 38 to 54 vol%, and lowering the tar yield from 0.050 to 0.014 g/g-fuel-daf. No apparent synergetic effect was observed in the case of biomass co-gasification, which might cause by the high Si content of landfill waste. In contrast, the H-2 production increases non-linearly with the biochar share in the fuel, which indicates that a significant synergetic effect occurs during co-gasification due to the reforming of tar over biochar. Increasing the temperature of biochar co-gasification from 800 to 1000 degrees C elevates the H-2 concentration, but decreases the H-2/CO ratio and increases the tar yield. Furthermore, the addition of biochar also enhances the gasification efficiency, as indicated by increased values of the energy yield ratio.

The use of H-ZSM-5 and Al-MCM-41 in a two-stage system of mesoporous and microporous catalysts has been proved to improve the quality of bio-oil. Information about biomass pyrolysis kinetics is important to evaluate biomass as a feedstock for fuel or chemical production as well as efficient design and control of thermochemical processes. In this study, the catalytic pyrolysis kinetics of lignocellulose biomass with a mixed catalyst of H-ZSM-5 and Al-MCM-41 at different ratios is analyzed. The derived activation energies are determined using the Coats-Redfern model and an Avrami mechanism for first-order chemical reactions (A1, F1). Bench-scale experiments as well as quantifications of the resulted benzene, toluene, and xylene (BTX) yields have also been investigated. The thermogravimetric analysis-DTG results show that the presence of catalyst mixtures has significant effects on the fractions of volatile matter from lignocellulose biomass. Reactivity profiles have been obtained in the temperature range of 180 to 360 °C. The results show that the energy activation for lignocellulose biomass at a heating rate of 10 K min-1 is 134.64 kJ mol-1 and that the value decreases when using catalysts. However, when the heating rate is increased, the activation energy from the catalytic experiments is 6.3-66.0% higher than that from the biomass pyrolysis experiment. This is due to the production of coke. Overall, a H-ZSM-5/Al-MCM-41 ratio of 3:1 is found to be the best catalyst ratio in cracking hemicellulose and cellulose compared to other catalyst mixtures that were studied. The same catalyst ratio also attains the best interaction, in terms of a BTX product selectivity. The optimum activity of this catalyst mixture is reached at a temperature of 500 °C. 

The use of H-ZSM-5 and Al−MCM-41 in a two-stage system of mesoporous and microporous catalysts has beenproved to improve the quality of bio-oil. Information about biomass pyrolysis kinetics is important to evaluate biomass as afeedstock for fuel or chemical production as well as efficient design and control of thermochemical processes. In this study, thecatalytic pyrolysis kinetics of lignocellulose biomass with a mixed catalyst of H-ZSM-5 and Al−MCM-41 at different ratios isanalyzed. The derived activation energies are determined using the Coats−Redfern model and an Avrami mechanism for firstorder chemical reactions (A1, F1). Bench-scale experiments as well as quantifications of the resulted benzene, toluene, andxylene (BTX) yields have also been investigated. The thermogravimetric analysis−DTG results show that the presence ofcatalyst mixtures has significant effects on the fractions of volatile matter from lignocellulose biomass. Reactivity profiles havecatayst mixtures as signicant eects on te ractions ovoatie matter rom ignoceuose iomassReactivity proes aveeen otainein te temperature range o180 to 360 CTe resuts sow tat te energy activation or ignoceuose iomassrate is increased, the activation energy from the catalytic experiments is 6.3−66.0% higher than that from the biomass pyrolysisexperiment. This is due to the production of coke. Overall, a H-ZSM-5/Al−MCM-41 ratio of 3:1 is found to be the best catalystratio in cracking hemicellulose and cellulose compared to other catalyst mixtures that were studied. The same catalyst ratio alsoattains the best interaction, in terms of a BTX product selectivity. The optimum activity of this catalyst mixture is reached at aattains te est interacti

Improvements on the pyrolysis process of biomass fuels are needed to obtain a high-quality of bio-oil. Pre-treatment by acid leaching prior to the pyrolysis process is considered to remove Alkali and Alkaline Earth Metal (AAEM) from the biomass, since AAEM adversely affect the catalytic pyrolysis process. Therefore, the main objective of the present work was to determine and compare the effect of mixed-catalysts consisting of H-ZSM-5 and Al-MCM-41, which are used at different ratios in lignocellulose biomass pyrolysis via Thermal Gravimetric Analysis (TGA) for both, un-leached and leached biomass. In addition, the activation energies have been determined based on the solid-state reaction mechanism. The results from the acid leaching treatment showed that the optimum leaching process was set to 30 min, 30 °C and 5 wt% acetic acid in the leaching liquid. This resulted in 59%, 95%, 99%, and 96% reduction degree of Calcium (Ca), Magnesium (Mg), Potassium or Kalium (K), and Natrium (Na), respectively. The Higher Heating Values (HHVs) for un-leached and leached biomass were 19.42 and 19.14 MJ/kg, respectively, calculated by using the Milne formula. The HHV value is not significantly influenced by the acid-leaching pre-treatment. Thermogravimetric analysis showed similar trends for the mass loss as a function of temperature and four stages could be determined from the thermal degradation of biomass. There was no significant shift in the temperature profiles between un-leached and leached biomass degradations. However, the removal of AAEM significantly affected the degradation of hemicellulose, cellulose, and lignin. A 12.4–18.2% increase of mass losses could be found in Phase 2 for leached biomass, compared to un-leached biomass. The mass losses in Phase 2 also increased with increased heating rates. From the un-leached biomass experiments using a catalyst mixture, the percentage of mass loss increased from 64.95 wt% at 10 K min−1 to 68.33 wt% at 50 K min−1. Moreover, for the leached biomass, it rose from 65.71 wt% at 10 K min−1 to 66.73 wt% at 30 K min−1, before decreasing to 62.44 wt% at 50 K min−1. A lower mass loss in Phase 4 for leached biomass compared to un-leached biomass showed the influence of an AAEM removal. The second order (F2) mechanism was able to illustrate the catalytic pyrolysis process, proven by the result that the coefficient of determination (R2) was higher than 0.99, which was high compared to other mechanisms. An acid leaching pre-treatment led to a reduction in the activation energies. The activation energies for the un-leached biomass were 26.94 and 25.56 kJ mol−1 at a heating rate of 10 K min−1 for a process without and with a catalyst mixture, respectively. The activation energies for leached biomass were 24.05 and 21.80 kJ mol−1. The results also showed that the use of the acid leaching process as a treatment prior to catalytic pyrolysis is positive, since it resulted in high devolatilization and reaction rate.

The appropriate system is needed to produce a scalable and economically viable renewable energy from biomass. The objective of this study is to improve the quality of bio-oil, in terms of Organic Liquid Product (OLP), water content, acidity, favourable fractions, as well as gasoline-range chemicals. The influence of a staged layered catalyst system consists of a mesoporous catalyst, Al-MCM-41, and a microporous catalyst, HZSM-5, on the bio-oil quality was investigated. Additionally, the effect of reaction temperatures in the range of 400–600 °C with the optimum staged catalyst system on the catalytic pyrolysis product was analysed. The experiments of lignocellulosic biomass pyrolysis and catalytic pyrolysis were performed using a fixed bed reactor equipped with oil condensers and a gas collection sample bag. The quality of bio-oil produced from the thermal pyrolysis of lignocellulosic biomass, catalytic pyrolysis with single catalysts, catalytic pyrolysis with the staged catalyst system, as well as catalytic pyrolysis with mixed catalyst system was studied. The results show that Al-MCM-41 with HZSM-5 in the staged catalyst system enhanced the production of favourable compounds: hydrocarbons, phenols, furans, and alcohols. The favourable compounds yield that boosted 5.25–6.43% of that with single HZSM-5 catalyst was produced with HZSM-5:Al-MCM-41 mass ratio of 3:1 and 7:1. The pyrolysis and catalysis temperature of 500 °C with HZSM-5:Al-MCM-41 ratio of 3:1 obtained the optimum quality of bio-oil with 11.08 wt.% of OLP, 76.20% of favourable fractions, 41.97 wt.% of water content, low TAN of 43.01 mg-KOH/g, high deoxygenation, as well as high gasoline-range production of 97.89%.