Batch Autoclave Research Articles

Hydrothermal gasification of sucrose

The earlier proposed two-step process, consisting of hydrogenation followed by hydrothermal gasification, for the conversion of carbohydrates is further developed by increasing its productivity, through the use of Pt and Ru catalysts in series. Aqueous sucrose is used as a model system to represent carbohydrate-rich waste water streams. In the first step, stabilisation, sucrose in a mass fraction of 10% in water is treated in a 45 cm3 batch autoclave reactor with H2 and is fully converted to sorbitol and mannitol at 413 K using a Ru catalyst with a 5% metal loading on a carbon support. A pseudo-first order kinetic model is developed and parameterised to support process development. In the second step, the stabilised mixture is gasified at 573 K using Pt and Ru catalysts with mass fractions of 5% on γ-Al2O3 and carbon supports respectively. The novel sequential combination of these two catalysts for gasification provides high H2 yields as well as high carbon to gas conversion (XCG). The carbon based weight hour space velocity (WHSVc) is increased from ca. 0.04 h−1 in previous work to 1 h−1 in this work. An energy balance shows that the ratio of the useable energy to the energy import, also termed ‘Energy Return On Energy Investment’ (EROEI) is ca. 5. This process provides an opportunity to simultaneously obtain clean water (TOC ∼ 4.7 g m−3) and produce valuable fuels (H2 and CH4) from carbohydrate-rich waste streams such as wastewaters from potato processing, fruit and vegetable processing industries.

Hydrothermal liquefaction of Chlorella vulgaris and Nannochloropsis gaditana in a continuous stirred tank reactor and hydrotreating of biocrude by nickel catalysts

Continuous hydrothermal liquefaction and further upgrading of the algal biocrude are of great importance for algae biofuel process scale-up and improvement of fuel properties. In this study, two strains of microalgae were used for processing in a continuous stirred tank reactor at 350 °C and 24 MPa for 15 min residence time. An average of 36.2 wt% and 31.5 wt% biocrude yields were achieved for Chlorella vulgaris and Nannochloropsis gaditana, respectively. The obtained biocrude was further upgraded by hydrotreating using commercial NiMo/Al2O3 and NiW/Al2O3 catalysts at two temperatures (250 °C and 400 °C) in a batch autoclave reactor for 4 h. Products distribution, analysis by elemental content, gas chromatography (GC), gel permeation chromatography (GPC), thermogravimetric analysis (TGA) and nuclear magnetic resonance spectroscopy (1H NMR) on upgrading products indicate that upgrading by both catalysts lead to improved physicochemical fuel properties, during 250 °C upgrading step, decarbonylation, decarboxylation and repolymerization are the dominant reactions while hydrodeoxygenation and cracking reaction are more promoted at 400 °C. The gasoline, kerosene and diesel oil components in the algal biocrude were increased from 18 wt% to >30 wt% after catalytic upgrading.

A kinetic model for a single step biodiesel production from a high free fatty acid (FFA) biodiesel feedstock over a solid heteropolyacid catalyst

Production of biodiesel from yellow grease (waste cooking oil and waste animal fats) is fast emerging as a promising alternative to address the twin challenges before the biodiesel industry today-fluctuation in prices of vegetable oil and the food versus fuel debate. Yellow grease has a high percentage of free fatty acids (FFA) and proves to be an unsuitable feedstock for biodiesel production from commercially viable alkali-catalyzed production systems due to saponification problems.“Green” methodologies based on heterogeneous solid acid catalyzed reactions have the potential to simultaneously promote esterification and transesterification reactions of yellow grease to produce biodiesel without soap formation and offer easy catalyst separation without generation of toxic streams. This paper presents kinetic studies for the conversion of model yellow grease feeds to biodiesel using a heteropolyacid supported on alumina (HSiW/Al2O3) using a batch autoclave. Three model yellow grease feeds were prepared using canola oil with added FFA such as palmitic, oleic and linoleic acid. A pseudo homogeneous kinetic model for the parallel esterification and transesterification was developed. The rate constants and activation parameters for esterification and transesterification reactions for the model yellow grease feeds were determined. The rate constants for esterification are higher than the transesterification rate constants. The kinetic model was validated using the experimental biodiesel data obtained from processing a commercial yellow grease feed. The kinetic model could be used to design novel processes to convert various low-value waste oils, fats and non-food grade oils to sustainable biodiesel.

Influence of carburization time on the activity of Mo2C/CNF catalysts for the HDO of guaiacol

Carbon nanofiber (CNF) supported β-Mo2C-based catalysts were synthetized by carbothermal hydrogen reduction at 750 °C for different times (1, 2, 4, 6 and 18 h) in order to study both the carbide phase formation and the CNF stability during this key stage. Catalysts were characterized by N2 physisorption, X-ray diffraction (XRD), X-ray photoelectron spectroscopy, inductively coupled plasma optical emission spectrometry and scanning transmission electron microscopy. Subsequently, catalysts were evaluated in the hydrodeoxygenation (HDO) of guaiacol using a batch autoclave reactor at mild conditions of temperature and pressure (300 °C and 20 bar of H2). Liquid products were analysed after 2 h of reaction by gas chromatography. In all cases, β-Mo2C phase was formed during the carburization, and crystal sizes increased (from 6 to 18 nm as measured by XRD) as the carburization time did. However, a deep gasification of the support was observed in catalysts carburized above 6 h, resulting in a dramatic loss of specific surface area. In the guaiacol HDO reaction, higher conversions (72–80 %) and HDO ratios (53–63 %) were obtained using catalysts carburized for 2 h and onwards. Considering the carbide content in the catalyst, 1 and 2 h carburized catalysts exhibited the highest values of formation of HDO products: phenol, cyclohexane + benzene and anisole. Besides this, a clear relationship between the Mo2C surface area (SMo2C) and the product formation rate could be inferred for the catalysts carburized at 1, 2 and 4 h, in which the textural properties were not affected by the carburization time. On the other hand, longer carburization times had a worse performance despite the largest values of SMo2C, being this fact related to the dramatic loss of the catalyst textural properties.

Rate enhancement of methane hydration in slurry of ice by phase change of water-in-oil emulsions

The paraffin, decane, octane and hexane, were chosen to make emulsions of the water-in-oil in terms of their lower fusion points and higher methane solubilities to study the methane hydration rate. The ice particles from supercooled emulsions provided the nucleation center and removed the hydration heat promptly through their reversed phase change. Meanwhile the solubility differences of methane in the paraffins and water enlarged the driving force of mass transfer. Finally, the hydration rates of methane were significantly enhanced in a batch autoclave at initial conditions of temperature from −1 to −5.7 °C, pressure 5.90 MPa, water-cuts 10–30 vol.% and stirrer speed of 700 rpm. The highest hydration rate reached 158.2 kmol h−1 m−3, which is obviously larger than those in the slurry of phase change material in water and the other achievements.

Static decontamination of oil-based drill cuttings with pressurized hot water using response surface methodology

Separating organic pollutants from oil-based drill cuttings (OBDC) is the current trend for its safe disposal. In this study, pressurized hot water extraction (PHWE) was adapted to decontaminate OBDC for the first time. Two typical OBDC samples, i.e., diesel-based drill cuttings (OBDC-A) and white oil-based drill cuttings (OBDC-B), were statically extracted in a homemade batch autoclave. Response surface methodology (RSM) with a central composite design (CCD) was applied to investigate the effects and interactive effects of three independent operating parameters (temperature, extraction time, and water volume) and to ultimately optimize the PHWE process. The results suggested that temperature is the dominant parameter, followed by water volume and extraction time. Interactive effects among the three parameters are present in the PHWE of OBDC-A but absent in the PHWE of OBDC-B. The suitable conditions for the effective PHWE of OBDC-A were found to be a temperature of 284-300°C, water volume of 15-35ml, and extraction time of 20-60min. The corresponding conditions were 237-300°C, 15-35ml, and 20-60min for the PHWE of OBDC-B. These different phenomena are caused by the different characteristics of the two OBDC samples. All of the polynomial models obtained from the RSM experiments are very valid and can adequately describe the relationship among the three independent operating parameters and responses. The experimental results also confirmed that PHWE is a more efficient separation technique for decontaminating OBDC than single organic solvent extraction or low-temperature thermal desorption because PHWE integrates the advantages of both these processes.

Improved Dispersion and Ultradeep Activity of HDS Catalyst by New Synthesis Approach

AbstractThe syntheses of highly dispersed NiMoS catalysts for ultradeep hydrodesulfurization (HDS) of refractory organosulfur compounds is carried out by adopting different metal deposition strategies on mesoporous silica: (i) single‐pot approach (SP), (ii) modified‐single‐pot approach (MSP); and (iii) addition of chelating agent (CA) with MSP (MSP‐CA). The characteristics of catalysts were evaluated by means of N2‐physisorption, chemisorption by thermal desorption and reduction (TPD and TPR), scanning electron microscopy (SEM), High resolution transmission electron microscope (HRTEM), and spectroscopy techniques; X‐ray diffraction (XRD), fluorescence (XRF), photoelectron (XPS), Fourier transform infrared (FTIR) and with pyridine adsorption (FTIR‐pyridine). Simultaneous desulfurization activity of dibenzothiophene (DBT) and dimethyl‐dibenzothiophene (4,6‐DMDBT) was carried out in a batch autoclave reactor at 350 °C and 5 MPa. MSP approach showed notable improvement in the Ni loading, textural properties and dispersion of active metals compared to the SP method. Consequently, MSP catalyst outperformed for the HDS rate of refractory organosulfur compounds (DBT and 4,6‐DMDBT) by both the direct desulfurization and hydrogenation routes. The addition of CA further improved the performance of MSP, especially for the HDS of 4,6‐DMDBT.

Kinetics of the synergy effects in heavy oil upgrading using novel Ni-p-tert-butylcalix[4]arene as a dispersed catalyst with a supported catalyst

This study investigates the promotional effects of implementing a co-catalytic system for hydrocracking of vacuum gas oil (VGO) that includes both dispersed and supported solid catalysts. A novel nickel-based p-tert-butylcalix[4]arene (Ni-TBC[4]) was employed as a dispersed catalyst in addition to a commercial first-stage hydrocracking supported catalyst. Slurry-phase hydrocracking was conducted isothermally under a hydrogen pressure of 8.5 MPa in a batch autoclave reactor by varying the reaction temperature (390–450 °C) and duration (0.5–1.5 h). The use of the synthesized metallocalixarene as a dispersed catalyst precursor enhanced the hydrogenation activity and noticeably reduced the coke and gas formation. The yields of coke and gases decreased upon introducing the dispersed catalyst along with the supported solid catalyst by 35.86% and 13.90%, respectively. The yield of naphtha increased from 15.27 wt% to 16.36 wt%, and that of distillate increased from 52.17 wt% to 53.57 wt% compared with the use of the supported catalyst, while the conversion of VGO was unchanged at about 83.20%. The value of the dimensionless catalytic activity parameter proved the existence of the synergy between the two catalysts since it is much higher than that acquired through the algebraically calculated yields. A five-lump discrete kinetic scheme was developed based on the experimental data governed from both the standalone supported catalyst and the mixed catalysts. The model incorporated the conversion of VGO to distillate, naphtha, and C1–C5 gaseous hydrocarbons in addition to coke deposition. The activation energy of the distillate formation was reduced from 65.39 kcal/mol to 57.32 kcal/mol by adding a Ni-TBC[4] catalyst precursor in the presence of supported catalyst.

Liquid phase pyrolysis of wheat straw and poplar in hexadecane solvent

There is a need for replacement of fuel, especially transportation fuel, obtained from fossil resources by bio-based alternative. The thermochemical conversion is a feasible method to degrade and partially deoxygenate the natural resource lignocellulose to get bio-oils as fuel precursors. The present paper describes the liquid phase pyrolysis of wheat straw and poplar under inert atmosphere in n-hexadecane solvent. An autoclave batch reactor system was used. The influence of reaction temperature, residence time, solvent/biomass ratio and the effect of solid acid and base catalysts on the product distribution and yields were investigated. The reaction products were analyzed by means of CHNO elemental analysis, Solid Phase Micro Extraction-Gas Chromatograpy-Mass Spectroscopy (SPME-GC–MS), 1H and 13C-Nuclear Magnetic Resonance (NMR) spectroscopies. About 40–49 wt% of lignocellulosic carbon was successfully transferred to hexadecane. The best carbon yields were achieved at 350 °C. The main extracted products were alkyl and alkoxy derivatives of phenol and furan derivatives. By comparing seven parallel experiments in presence and absence of the catalysts no or only negligible catalytic effect was observed. The effect of heterogeneous catalysts was manifested only in splitting the primarily extracted macromolecules. The carbon/oxygen mass balances suggest that the extracted compounds have relatively high residual oxygen content.

Designing supported NiMoS2 catalysts for hydrocracking of vacuum residue

In order to design a suitable catalyst for hydrocracking (HCK) of vacuum residue (VR), a series of NiMoS/γ-Al2O3 catalysts were prepared with varying Mo loading amounts, Ni addition, P addition, and porosity of γ-Al2O3 support, and were applied for the VR HCK. Activity tests were conducted in an autoclave batch reactor at 693 K and 10 MPa H2 for the VR HCK in the presence of 0.26 wt% catalyst and 33.0 wt% tetralin. X-ray absorption spectroscopy (XAS), N2-physisorption, H2-temperature programmed reduction (H2-TPR), and energy dispersive X-ray fluorescence (ED-XRF) measurements were applied to verify the physical properties of the prepared catalysts. The amount of Mo loadings on γ-Al2O3 was observed most favorable at 8.0 wt% with the asphaltene conversion of 62.9%. The addition of Ni had minimal effect on the VR HCK, but the effect on the hydrodesulfurization (HDS) of VR was significant. It was noteworthy that the increase in porosity of the γ-Al2O3 support played an important role in enhancing the asphaltene conversion to 68.5%.

Experimental studies on production of deoxygenated vegetable oils and their performance evaluation in a compression ignition engine

The present experimental investigation aims at production of second-generation biofuels from straight vegetable oils (SVOs) and carrying out their performance assessment in a compression ignition (CI) engine. The intended second-generation biofuels, i.e., deoxygenated vegetable oils (DVOs), were produced through catalytic deoxygenation of palm and karanja SVOs over 5 wt% Pd/C catalyst under an inert (N2) atmosphere using a batch autoclave reactor. Fuel characterization and elemental analysis were carried out for the produced DVOs to evaluate various fuel properties. In order to evaluate the fuel composition and presence of diesel range aliphatic hydrocarbons, GC-MS and FT-NMR tests were carried out. The engine performance and emission characteristics with the DVOs were evaluated in a developed experimental diesel engine setup. Results showed that the DVOs exhibit better engine performance, lower emissions, and marginally higher NOx emissions compared to those with diesel fuel. In order to establish the DVOs as possible CI engine fuels, the performance and emission characteristics with the DVOs were compared against those with their corresponding established B20 biodiesel blends. The comparative assessment revealed that the engine performance and emission characteristics with the DVOs are superior compared to those with the corresponding B20 biodiesel blends. Especially, the NOx emissions with the DVOs are significantly lower as compared to their corresponding B20 biodiesel blends.

HYDROTHERMAL LIQUEFACTION OF MAHOGANY (Swietenia macrophylla) SAWDUST

Hydrothermal treatment is one of the thermochemical methods to convert complex organic compounds, such as organic waste and biomass, into upgraded solid, bio-oil, and other dissolved chemicals by utilizing the properties of water at near critical condition. Such method is very potential since the process is environmentally friendly and the products have more added values. In this research, conversion of mahogany sawdust (Swietenia macrophylla) using hydrothermal treatment method was studied. The experiments were conducted in a batch autoclave with temperature range of 200-300oC and initial pressure of 1 MPa. At targeted temperature, the process was hold for 30 minutes. In addition, biomass-water ratio (B/W ratio) for experiments was varied at 1:20, 2:20 and 3:20. The liquid products, which were characterized by Gas chromatography-Mass spectrometry (GC/MS) instrument, showed the presence of furfural and several organic acids, but no flavonoid compounds. Thus, coloring potential test of hydrothermal liquid was unsuccessful; there were not any color attached on the cloth specimen. On the other hand, proximate and ultimate test results indicated that solid products had high heating value (HHV) of 4625.34-4876.25 cal/g which were comparable to that of sub-bituminous coal.

Stability of AuCl2− from 25 to 1000 °C at Pressures to 5000 bar and Consequences for Hydrothermal Gold Mobilization

Gold is transported in high-temperature chloride-bearing hydrothermal fluids in the form of AuCl2−. The stability of this complex has been extensively studied, but there is still considerable disagreement between available experimental data on the temperature region 300–500 °C. To solve this problem, we measured the solubility of gold in HCl/NaCl fluids (NaCl concentration varied from 0.1 to 3 mol·(kg·H2O)−1) at 450 °C and pressures from 500 to 1500 bar (1 bar = 105 Pa). The experiments were performed using a batch autoclave method at contrasting redox conditions: in reduced experiments hydrogen was added to the autoclave, and in oxidized experiments the redox state was controlled by the aqueous SO2/SO3 buffer. Hydrogen pressure in the autoclaves was measured after the experiments in the reduced system. The gold solubility constant, Au(cr) + HCl°(aq) + Cl− = AuCl2− + 0.5 H2°(aq), was determined for the experimental T-P parameters as log Ks° = −4.77 ± 0.07 (500 bar), −5.11 ± 0.08 (1000 bar), and −5.43 ± 0.09 (1500 bar). These data, together with values from the literature for temperatures from 25 to 1000 °C, were fitted to the simple equation log Ks° = 4.302 − 7304∙T(K)−1 − 4.77∙log d(w) + 11080∙(log d(w))∙T(K)−1 − 6.94 × 106∙(log d(w)) T(K)−2, where d(w) is the pure water density. This equation can be used together with the extended Debye–Hückel equation for activity coefficients to calculate gold solubility at pressures up to 5000 bar at fluid chlorinities at least up to 30 wt %. The speciation of gold in natural chloride-bearing fluids is discussed.

Sequential Condensation and Hydrodeoxygenation Reaction of Furfural-Acetone Adduct over Mix Catalysts Ni/SiO<sub>2</sub> and Cu/SiO<sub>2</sub> in Water

Sequential condensation and hydrodeoxygenation reaction were perform using autoclave batch reactor in the presence of water as a solvent. The condensation of furfural and acetone was performed using MgO catalyst followed by hydrodeoxygenation using mix catalyst Ni/SiO2 and Cu/SiO2. The catalyst was prepared by wet-impregnation method and analyzed by XRD, SEM-EDX as well as BET surface. Condensation of furfural and acetone in 1:2 mol ratio was carried out by reflux gave 4-(2-furyl)-3-buten-2-one and 1,5-bis-(2-furanyl)-1,4-pentadien-3-one. The condensation product was then subjected for hydrodeoxygenation using batch reactor, catalyzed by mixed Ni/SiO2 and Cu/SiO2 at 150 and 180 °C for 2 h. The product identified as alkane derivatives with the conversion at 38.83 and 50.35%, respectively. The selectivity of hydrocarbon is 61.39% at 150 °C and 16.55% at 180 °C. Increasing the reaction temperature to 200 °C did not give any products except the recovery of the precursor. It showed that higher temperature enhanced the catalyst activity but the selectivity is controlled by low reaction temperature.

Continuous biodiesel production under subcritical condition of methanol – Design of pilot plant and packed bed reactor with MnCO3/Na-silicate catalyst

The continuous biodiesel production from soybean oil was carried out under the subcritical condition of methanol with MnCO3/Na-silicate as a heterogeneous catalyst. The transesterification rate was first investigated in a set of experiments performed in a batch autoclave at 448 K using methanol-to-oil molar ratio of 18:1 and various catalyst loadings (5, 10 and 20 wt% based on the oil mass). The results from these experiments, as well as the experimental data and the appropriate kinetic model recently reported in the literature were used for designing a packed bed tubular reactor (PBTR), a main unit of the pilot plant with the capacity of 100 L of biodiesel per day. The pilot plant was constructed and tested under various operating conditions. The first 11 h of the pilot-plant operation was realized in the tubular reactor packed with inert glass beads (i.e. without the catalyst) in order to analyze the effect of the non-catalyzed subcritical biodiesel (fatty acid methyl esters, FAME) production. Then, glass beads were replaced with a mix of MnCO3/Na-silicate catalyst particles and glass beads, and the catalytic biodiesel production was continuously run under the subcritical methanol condition for 85 h. Two mass balance tests during the continuous pilot plant operation were performed.

Hydrogenation of Nickel Octaethylporphyrin over Dispersed MoS2 Catalysts Formed In Situ

AbstractHydrogenation of nickel octaethylporphyrin (Ni‐OEP) over dispersed MoS2 catalysts was studied in a batch autoclave at relatively low temperatures ranging from 553 K to 593 K. In spite of the transformation of catalytic species, invariant rate constants are acceptable to analyze the kinetics in the given temperature range. It turns out that the first hydrogenation of Ni‐OEP is the rate limiting step when the dispersed catalysts are present. With the combined analysis of XRD and XPS patterns, Ni species deposited on the surface of the catalysts were determined. As much as 66.7% of nickel exists in the mixed “NiMoS” phase, and a small amount of sulfided phase of nickel is implied. The influence of metal deposits on the catalytic activity of catalysts for hydrogenation was evaluated using anthracene as the model compounds. The conversion of anthracene over MoS2 shows to be promoted with Ni‐OEP added. It is suggested that Ni‐OEP could be hydrogenated and involved with the formation of active catalytic species. As a result, Ni‐OEP could cooperate with the dispersed MoS2 catalyst for catalyzing the anthracene hydrogenation.

Influence of biomass pretreatment on upgrading of bio-oil: Comparison of dry and hydrothermal torrefaction

The dry and hydrothermal torrefacation of on Camellia Shell (CS) was carried on three different devices- batch autoclave, quartz tube, and auger reactor. The torrefied bio-char products were investigated via TGA, elemental analysis and industrial analysis. Moreover, the pyrolysis and catalytic pyrolysis properties of torrefied bio-char were investigated. The results showed torrefaction significantly influenced the content of hemicellulose in CS. And hydrothermal torrefaction via batch autoclave and dry torrefaction via auger reactors promoted the hemicellulose to strip from the CS. Quartz tube and auger reactor were beneficial for devolatilization and improving heat value of torrefied bio-char. The result showed that the main products were phenols and acids. And hydrothermal torrefaction pretreatment effectively reduced the acids content from 34.5% to 13.2% and enriched the content of phenols (from 27.23% to 60.05%) in bio-oil due to the decreasing of hemicellulos in torrefied bio-char. And the catalyst had slight influence on the bio-oil distribution.

Effects of minerals on steam distillation during thermal heavy-oil recovery: An experimental investigation

ABSTRACTAn experimental study was carried out to investigate the role of various clay and non-clay minerals present in reservoir formations on steam distillation process. Dead oil samples (100 g) of two heavy oil reservoirs with 30 g of water and 10 g of crushed rock mixed with different clay minerals were kept under steam pressure with 150, 200, and 250°C in a batch autoclave reactor for a period of 40 hours, and the results were compared with respect to the changes in the density, viscosity and chemical composition of remaining heavy oil. Three different clay minerals (bentonite, kaolinite, and sepiolite) were added to the crushed rock to observe their effects. Among these clay minerals, kaolinite had the greatest effect on steam distillation. Kaolinite has an inert surface compared to other clay minerals which can be considered as an catalytic effect to make easier the evaporation of the volatile components of heavy oil during steam distillation. On the other hand, bentonite which has a swelling property in the presence of water may not allow the entrance of oil molecules because of its low permeability has retard/decrease the evaporation of volatile components. In case of kaolinite addition, density and viscosity of remaining oil are the greatest comparing with the two other minerals added. In addition, the asphaltene content of the remaining oil after distillation increased compared to original oil sample for all added clay minerals.

Liquefaction of natural rubber to liquid fuels via hydrous pyrolysis

In this study, the natural rubber (NR) was liquefied to produce liquid fuels using hydrous pyrolysis technique. The study was performed in the autoclave batch reactor at different temperatures (300–400 °C), with different water to natural rubber mass ratios (1:1–5:1) and different reaction times (15–75 min). The effect of different parameters then was evaluated on the liquid product in term of quantity and quality. The results showed that the highest liquid yield of 76 wt% was obtained at temperature, H2O/material mass ratio and time of 375 °C, 3:1 and 30 min respectively. Among the parameters, temperature was found to be the most important parameter, showing a notable positive effect on the liquid oil quality and quantity. The characterization results showed that the oil had high energy density, low oxygen and sulfur contents, and non-acidic. The GC–MS analysis showed that the obtained oil was dominated by alkenes, aromatics and alkyls. From all characteristic results it showed that the oil from NR was more suitable to be used as fuel compare to the oil derived from scrap tire, where the study on hydrous pyrolysis of scrap tire was also provided in this manuscript as comparative study. In addition, the production of oil from the hydrous pyrolysis of NR in Malaysia could add to the energy potential about 15 PJ/year or equivalent to 2.5 million barrels of oil per year.

Hydrothermal liquefaction of high- and low-lipid algae: Mass and energy balances

Hydrothermal liquefaction (HTL) of high-lipid microalgae Nannochloropsis salina (N. salina) and low-lipid microalgae Galdieria sulphuraria (G. sulphuraria) were run under subcritical conditions (310–350 °C and 10–17 MPa) in a 1.8 L batch autoclave system. HTL mass and energy balances for both species were compared under different operating conditions to predict the optimum reaction conditions for new algae strains based on their feedstock composition. Bio-crude oils and chars were characterized by bomb calorimetry, elemental analysis, inductively coupled plasma optical emission spectrometry (ICP-OES), and thermogravimetric analysis (TGA). Under the optimized conditions, 59 wt% and 31 wt% bio-crude oil yields were obtained from HTL of N. salina and G. sulphuraria, while 85% and 59% of the feedstock energy were partitioned into N. salina-derived and G. sulphuraria-derived bio-crude oils, respectively. More favorable energy balances were related to shorter reaction times and higher algal solid contents.