HHV Value Research Articles

Co-liquefaction of Prosopis juliflora with polyolefin waste for production of high grade liquid hydrocarbons

In this study, co-liquefaction (HTL) of Prosopis juliflora (PJ) biomass with polyolefin waste (PO) was performed to produce bio-oil. HTL on bio-oil yield was studied at varying PJ to PO ratios (0:1, 1:0, 1:1, 2:1, 3:1, 4:1 and 5:1) and temperatures from 340 to 440 °C. Bio-oil and HTL by-products were characterized by Mass Spectroscopy (GC–MS) and Fourier Transform Infrared Spectroscopy (FTIR) analysis. Bio-oil yield was around 61.23%wt at 420 °C for 3:1 blends with 3 wt% of HCl activated bentonite catalyst at 60 min holding time. HHV value was 46 MJ/Kg with 88.23% purity (petro-diesel). Additionally gas possessed 26.28% of Hydrogen gas, 45.59% of Carbon dioxide gas, 7.1% of Carbon monoxide gas, 8.12% of Methane gas and other elements. The energy recovery (78%) and carbon recovery (94%) was higher for 3:1 blends bio-oil than PO and PJ processed bio-oils. HTL wastewater possessed higher degree of reusability nature as HTL medium.

Hydrothermal conversion of biomass (Xanthium strumarium) to energetic materials and comparison with other thermochemical methods

In the present study, the biomass was converted into liquid and solid residues by using hydrothermal liquefaction method at 250, 300 and 350 °C with (FeCl3, NaOH) and without catalyst. The resultant products were examined using GC–MS, FT-IR, 1H NMR, SEM, and elemental analysis methods. According to the performed analyses, the highest liquid product yield (total bio-oil) was found to be 38.08% at 300 °C by using FeCl3 as catalyst. In the experiments carried out at 350 °C, the highest HHV value was found to be 32.35 MJ kg−1 by using NaOH catalyst. The energy values of products obtained at the end of experiments were compared to the values obtained from pyrolysis and supercritical liquefaction method, and it was determined that the liquid products having higher level of energy value were achieved by using hydrothermal liquefaction method.

Hydrothermal liquefaction of Syrian mesquite (Prosopis farcta): Effects of operating parameters on product yields and characterization by different analysis methods

In this study, the effect of temperature and catalyst on hydrothermal liquefaction of biomass was investigated. At the end of the experiments, prosopis farcta plant was transformed to solid residue (bio-char) and liquid products (heavy bio-oil, light bio-oil) at temperatures of 250, 300 and 350 °C with catalyst (H3BO3, Na2B4O7·10H2O, NaOH) and without catalyst by hydrothermal liquefaction. The liquid and solid products obtained at the end of the experiments were analyzed by GC–MS, FT-IR, 1 H NMR, SEM and elemental analysis methods. The highest liquid product yield was obtained at 350 °C with sodium tetraborate catalyst as 35.69%. According to the elemental analysis results, the HHV values of the liquid products range from 19.75 to 29.54 MJ kg−1 for 300 °C and from 18.06 to 30.02 MJ kg−1 for 350 °C. HHV values of all obtained liquid products were found to be higher than raw materials.

Cyanobacteria pyrolysis with methanol catalyzed by Mg-Al hydrotalcite-derived oxides/ZSM-5

ABSTRACTThe Cyanobacteria was catalytically pyrolyzed in methanol atmosphere using magnesium-aluminum layered double oxide/ZSM-5 composites (MgAl-LDO/ZSM-5) as a catalyst. The largest liquid yield of 67.68% was obtained in methanol atmosphere, which was much higher than that obtained without methanol under same reaction condition. The Gas chromatography-Mass spectrometer data proved that the organics phase contained less O-compounds and N-compounds and more aromatic compounds. And the ultimate analysis results showed that this bio-oil had much higher HHV values and lower O/C molar ratio. The co-processing methanol atmosphere and bifunctional catalyst would be a promising means for improving the quality of bio-oil.

Chlorella sorokiniana thermogravimetric analysis and combustion characteristic indexes estimation

This work aimed to investigate thermal decomposition of microalgae throughout the different culture stages. For this purpose, Chlorella sorokiniana was cultured in photobioreactors, and microalgae biomass was sampled at different days throughout the development of the culture. The aim was to analyze the energetic value of this biomass by thermogravimetric analysis as well as to calculate combustion characteristic indexes during the different culture stages. In all cases, thermal decomposition of microalgae biomass during combustion denoted two stages. The first one encompassed the carbohydrates and proteins decomposition and the breakdown of hydrocarbon chains of fatty acids, whereas the second step was closely related to the combustion of the formed char. Fuel composition analysis denoted a microalgae HHV value quite similar to that of Poplar (considered as an energy crop) biomass and slightly higher than published values for herbaceous biomass. In relation with the culture stages, a better combustion performance was found (higher thermal indexes as well as higher DTGmax values) for microalgae biomass sampled at days 19 and 21. These results point to the importance of the culture stage for the thermal valorization of microalgae biomass.

Evolution of the chemical composition, functional group, pore structure and crystallographic structure of bio-char from palm kernel shell pyrolysis under different temperatures

Biochar, produced from the biomass slow pyrolysis technology, has been widely applied to the industry and agriculture. This paper investigated the effect of the pyrolysis temperature (250, 350, 450, 550, 650, and 750°C) on the chemical composition, functional group, pore structure and crystallographic structure of biochar from palm kernel shell (PKS). The basic properties of biochar was mainly tested by a serial instruments including thermogravimetric analyzer (TGA), fourier transform infrared spectrometry (FTIR), automatic adsorption analyzer, X-ray diffractometer (XRD), Raman spectra, and solid-state 13C nuclear magnetic resonance spectra (13C NMR). The results showed that as the pyrolysis temperature increased: (1) the carbon content, HHV and pH value reached their maximum values of 78.95%, 31.55MJkg−1 and 10.03 at 750°C, respectively, (2) the content of the surface functional group decreased, (3) the oxygen-contained carbon structure including O-alkyl-C and carboxylic-C decreased from 11.71% and 3.72% to 1.12% and 1.11%, respectively, while the aryl-C structure increased from 65.98% to 93.18%, (4) the specific surface area (SBET) reached the maximum value of 403.99m2g−1 at 650°C. This systematic study on the evolution of the basic physicochemical characteristics will provide a good reference for the high value-added application of PKSC.

Bamboo Torrefaction in a High Gravity (Higee) Environment Using a Rotating Packed Bed

Biomass torrefaction in various reactors has been extensively studied lately. Different from past studies, torrefaction of raw bamboo (Phyllostachys mankinoi) in a high gravity (Higee) environment is investigated where a rotating packed bed (RPB) for intensifying heat and mass transfer between gas and solid is used for the process. Three rotating speeds of 0, 900, and 1800 rpm, corresponding to the mean centrifugal forces of 0, 58, and 234 g, are taken into account. The results suggest that the Higee environments intensify the torrefaction performance drastically when the operations of light (206 °C) and mild (255 °C) torrefaction are practiced, stemming from the enhancement of heat and mass transfer in the rotating bed. In contrast, the torrefaction performance is affected slightly by the rotating speed when severe torrefaction (300 °C) is carried out. With the torrefaction conditions of 300 °C and 1800 rpm, the highest HHV (28.389 MJ/kg) with an HHV enhancement factor (EF) of 1.61 is obtained, yielding a coal-like fuel, and the energy yield is 63.51%. The torrefaction operation at 255 °C and 1800 rpm for 30 min upgrades the EF (1.53), HHV (26.988 MJ/kg), and energy yield (65.21%) values of the bamboo, which are close to those of the torrefied biomass under the most severe torrefaction conditions, and is thus recommended. The results suggested that torrefaction in a Higee environment is a promising process for upgrading biomass to produce carbon-neutral fuel utilized in industry.

Catalytic co-cracking of distilled bio-oil and ethanol over Ni-ZSM-5/MCM-41 in a fixed-bed

The bio-oil from rice hull fast pyrolysis was distillated under reduced pressure at 0.005 Mpa, then mixed with ethanol (2:3 by weight). The mixture was subjected to catalytic co-cracking over Ni-ZSM-5/MCM-41 molecular sieves in a fixed-bed at 500 °C and 3.75 h−1 of the WHSV. The distillation results showed the distilled bio-oil, compared with raw bio-oil, contained lower oxygen content (decreased from 45.91 wt.% in raw bio-oil to 33.74 wt.%), higher (H/C)eff ratio (0.35) and HHV value (22.81 MJ/kg). The ethanol was involved in the ketonization, esterification, aromatization and dehydration during the catalytic co-cracking of distilled bio-oil and ethanol. The Ni loaded on ZSM-5/MCM-41 molecular sieves reduced char formation compared with ZSM-5/MCM-41. The ZSM-5/MCM-41 catalyst exhibited higher activity in the esterification and aromatization, which converted acids in upgraded bio-oil to esters, aromatics or phenols. The Ni-ZSM-5/MCM-41 catalysts showed excellent activity that transformed acids to ketones by ketonization process. The 6% Ni-ZSM-5/MCM-41 catalyst performed the good activity with the minimum char formation (7.3 wt.%) and higher upgraded bio-oil (40.8 wt.%). Moreover, the acid content in the upgraded bio-oil dropped to 0.1 wt.% and the total concentration of CO2 and CO in the gas products was 36.8 vol.%.

Catalytic pyrolysis of recalcitrant, insoluble humin byproducts from C6 sugar biorefineries

Humins are solid by-products formed during the acid-catalysed conversions of C-6 sugars to platform chemicals like hydroxymethylfurfural and levulinic acid. We here report an experimental study on the liquefaction/depolymerisation of humins using catalytic pyrolysis. Synthetic humins (SH) and crude industrial humins (CIH, including purified industrial (PIH) samples) from the acid-catalysed conversion of C-6 sugars to HMF/LA were tested. Thermal degradation patterns of both humin types vary significantly. Major thermal decomposition of the industrial humins was observed between 50 and 650°C (weight loss approx. 66wt%), whereas, major weight loss was observed between 200 and 800°C for the synthetic humins (47wt%). A series of catalytic pyrolysis tests with synthetic humins and different zeolites were performed using a PTV-GC/MS (humin to catalyst wt ratio of 0.2, 550°C). Best results were obtained using HZSM-5 (SiO2/Al2O3=50). For quantitative analysis, a gram scale pyrolysis unit was used, giving a product oil (9–11wt% on humin intake) with approximately 1.5 and 10wt% aromatics from synthetic and crude industrial humins, respectively. GPC data on the product oils clearly shows the breakdown of the humin structure into low molecular weight species. The HHV value of the liquid products (up to 41MJkg−1) is considerably higher than that of the crude industrial humin feed (21–24MJkg−1).

Influence of mid-point temperature of heavy hydrocarbons separator to the liquefaction process for small LNG plant

In liquefied natural gas (LNG) process production, one of the important units is heavy hydrocarbon removal unit to prevent freezing during liquefaction. For small scale of LNG plant, this unit is usually integrated with main heat exchanger. Feed is obtained from main heat exchanger then flows to separator to separate liquid from gas. The separator operating condition is called as Midpoint condition. Selecting Midpoint conditions have impact to light hydrocarbon losses, Specific Brake Horse Power (SBHP) process, and heating value of LNG. Hence understanding of selecting this condition and its effect to light hydrocarbon losses, SBHP process, and HHV of LNG will help to design more efficient LNG plant. According to study, the lower of Mid-Point temperature will result in lower SBHP, lower of light hydrocarbon losses, and increase LNG of HHV value. Meanwhile, the higher Mid-Point pressure will result in lower SBHP, higher light hydrocarbon losses, and lower LNG of HHV value. The change of Mid-Point pressures have more impact to light hydrocarbon losses than SBHP process.

Effect of process parameters on supercritical liquefaction of Xanthium strumarium for bio-oil production

Supercritical liquefaction process is used for producing energy from biomass. The common reaction conditions for supercritical liquefaction process are the 240–380°C temperature range and 5–20MPa pressure values range. Xanthium strumarium liquefaction experiments were performed in a cylindrical reactor (75mL) in organic solvents (acetone, ethanol, methanol) under supercritical conditions with (zinc oxide, calcium hydroxide) and without catalyst at the temperatures of 250, 275 and 300°C. The produced liquids at 300°C in liquefaction were analyzed and characterized by Elemental, GC–MS and FT-IR. 36, 37 and 50 different types of compounds were identified by GC–MS obtained in acetone, ethanol and methanol respectively. The liquid product efficiency has been obtained at 300°C in acetone with zinc oxide catalyst (74.80%). The highest HHV value has been calculated as 32.16MJ/kg with calcium hydroxide catalyst in acetone.

A Simplified Model for Gasification of Oil Palm Empty Fruit Bunch Briquettes

This study is aimed at investigating the product gas yield and composition of EFB briquettes gasification using a simplified stoichiometric equilibrium model. Similar mathematical models have been successfully adopted by a number of research groups to investigate the thermochemical conversion of biomass species. Hence the effect of gasification temperature on the product gas yield and composition of EFB briquettes gasification using a simplified stoichiometric equilibrium model is presented in this study. The results indicate that the H2 and CO content increased with increasing temperature from 600 to 800°C while the CO2, N2 and CH4 content decreased. The H2 content increased with increasing temperature, with peak production of 25.55 mol % at 750°C. The HHV (4.87 to 8.38 MJ/Nm3), CGE (27.72 to 47.71%) and CCE (25.42 to 41.54%) values increased with increasing temperature during gasification. Hence for a reacting system with known reaction mechanism, the model can be used to reasonably deduce the yield and composition of the gasification products.

Fast oxidative pyrolysis of sugar cane straw in a fluidized bed reactor

This study focuses on the technical viability evaluation of the fast pyrolysis of sugar cane straw for its energy use. By means of this thermochemical process, the sugar cane straw is converted into bio-fuels (biochar, bio-oil) and non-condensable gases. The bio-fuels obtained could be used as fuel or as raw material in the chemical industry. The fast pyrolysis of sugar cane straw has been developed in a fluidized bed reactor. In order to improve this process to obtain high bio-oil yield, the influence of the operational conditions (equivalence ratio and temperature) on the product yields and on their characteristics was evaluated. The product yields of bio-oil and char were up to 35.5 wt.% and 48.2 wt.% respectively. The maximum bio-oil yield was achieved at temperature and equivalence ratio conditions of 470 °C and 0.14. The bio-oil obtained has low oxygen content (38.48 wt.% dry basis), very low water content, and a lower heating value of 22.95 MJ/kg. The gas chromatographic analyses allowed the identification of oxygenated compounds and heterocyclic aromatic hydrocarbons. The bio-oil pH ranged between 3.14 and 3.57 due to the presence of acid organic compounds. The char obtained has a high fixed carbon and volatile matter content. Its HHV value is 13.54 MJ/kg.

Compositional and Thermal Evaluation of Lignocellulosic and Poultry Litter Chars via High and Low Temperature Pyrolysis

Inorganic elements in biomass feedstocks can influence thermochemical reactions as well as the resultant char’s elemental, compositional, and thermal characteristics. Chars were produced using slow pyrolysis under low (≤400°C) and high (≥500°C) temperature regimes from sugarcane bagasse, peanut hulls, pecan shell, pine chips, poultry litter, and switchgrass. The chars and raw feedstocks were characterized for their elemental, structural, and thermal properties to ascertain the implications of feedstock selection and pyrolysis temperatures on these properties. Char mass yields from the six feedstocks ranged between 28% and 78% by weight while carbon yields ranged between 44% and 89%. In both instances, lower yields were obtained with increasing pyrolysis temperature. Higher pyrolysis temperatures (≥500°C) resulted in more neutral to alkaline chars possessing greater ash contents and increased aromatic character with narrow O/C and H/C ratios. A significant exponential curve response (r2 = 0.87, P 30 MJ kg−1. The chars’ HHV values inversely correlated to their total ash and Cl content. Lignocelluloses chars had better thermal characteristics and lower ash quality concerns implying suitable service in thermal energy production. In contrast, poultry litter char had greater ash contents, medium HHV values, and contained corrosive inorganic elements, which rendered it problematic as a feedstock for thermal energy generation.

Evaluation of Four Poplar Clones in a Short Rotation Forestry in Central Italy

Two field experiments were carried out in 2006 and 2007 in central Italy (42°57’N, 12°22’E, 165 m a.s.l.) in order to investigate the influence of site, planting densities/spacings and cutting cycles on the biomass production of four poplar clones [(Populus – generosa) – Populus nigra “Monviso” and “AF6”, Populus – canadensis “AF2”, Populus deltoides – Populus – canadensis “SIRIO”] selected for SRF. Hardwood cuttings of each clone were planted at two different densities and planting designs: a) low density = 5500 cuttings ha-1 were placed in a single-row design; b) high density = 11000 cuttings ha-1 were placed in a coupled-row design, and were tested with two cutting cycles: one-year cycle and two-year cycle. The experimental design was a split-plot with three replicates. The initial survival of clones was recorded after the establishment period. The number of shoots per plant (stool) was determined after the first growing season. Plant height (height of the main stem), main stem diameter at a height of 1 m and of 1.3 m above the ground and biomass production were measured from each plot, every year at harvesting time at the end of the growing season. Plant samples were also taken in order to assess humidity content, lower and higher heating values (LHV and HHV) and ash content of poplar biomass. All poplar clones showed a very high stool survival with values ranged from 95% to 99%. Monviso and AF2 can be advisable thanks to the higher biomass production than AF6 and Sirio. Considering planting density, low density (5500 plants ha-1) seems to be more advisable than high density (11000 plants ha-1) in order to obtain good biomass production with low planting cost. Considering cutting cycles, two-year cutting cycle allows higher biomass production (5.8 odt ha-1 year-1) than oneyear cutting cycle (4.7 odt ha-1 year-1), regardless of clones or density. Concerning main stem height and diameter some interesting equations were found in order to explain the relationship between them or with biomass production. In particular, a functional relationship between dry biomass production and stool diameter, appropriate for this climatic area and environmental conditions, was found. Analysis concerning wood energy content showed a good quality of poplar biomass thanks to high HHV and LHV values (an average of 19.7 MJ Kg-1 and 19.4 MJ Kg-1), low ash content (an average 3.6%) and low biomass humidity at harvest (an average 54%).