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Timely and precise diagnosis of ischemic cardiac events based on electrocardiogram is challengeable among patients with Left Bundle Branch Block (LBBB). The present study aimed to assess the correlation between SYNTAX score and terminal T-wave morphologies among LBBB patients suspected of Acute Coronary Syndrome (ACS) without modified Sgarbossa criteria. This cross-sectional study was conducted on the LBBB patients suspected of ACS without modified Sgarbossa criteria. Binary logistic regression was used to assess the correlation of ischemic heart disease (IHD, SYNTAX score > 0) and SYNTAX score categories with terminal T-wave morphologies including T-wave direction in lead V6 and terminal T-wave concordance in leads I, V5, and V6. This study was done on 93 patients with the mean age of 62.4 ± 9.6 years. More than half of the patients were female (58.1%, 95% CI: 47.4% to 68.2%). Among the participants with IHD, the SYNTAX score categories were correlated to discordant terminal T-wave in leads I, V5, and V6 (OR = 5.71, 95% CI: 1.04 to 31.28, p = 0.04). Among the LBBB patients with acute ischemic cardiac events without modified Sgarbossa criteria, those with discordant terminal T-waves in leads I, V5, or V6 had higher SYNTAX scores and might require more invasive coronary revascularization techniques such as Coronary Artery Bypass Graft (CABG) surgery. [ABSTRACT FROM AUTHOR]

Due to many benefits of heavy oil upgrading in the green medium of hot compressed water (HCW), the present study considers the thermodynamic analysis of in-situ hydrogen created by partial oxidation of light hydrocarbons (HC) in HCW. The aim is seeking the upgrading condition where light hydrocarbons create hydrogen (H 2) and carbon monoxide (CO) assisted by partial oxidation of light hydrocarbons. The formed CO collaborates in in-situ active hydrogen through water gas shift reaction (CO+H 2 O↔H 2 +CO 2) which is more effective than external hydrogen for hydrogenation of heavy oil in HCW. Applying the powerful capability of Aspen Plus®, i.e., sensitivity analysis, the effect of significant parameters, such as temperature, pressure (water density), water to oil ratio, and oxygen (O 2) to oil ratio are studied comprehensively in order to maximize the amount of active hydrogen. The results indicate that higher temperatures and the amount of water (H 2 O/heavy oil) are two favorable factors to increase the contribution of active hydrogen, while the pressure is not a determinant factor at supercritical condition (P ≥ 25 MPa). The formation of methane is also decreased at high temperature which is desired for upgrading system. The higher amount of water implies more quantity of O 2 since partial oxidation affords the enthalpy of auto-thermal reforming of HO. Hence there should be a compromise in the selected ratios of H 2 O/HC and O 2 /HC in HCW upgrading system. A set of experiments are conducted in order to compare the simulation and experimental results. Although the experimental results are established on kinetic data which also reflect the physical effect of HCW during HO upgrading, however, the thermodynamic study provides valued information, in agreement with experiments, that improves our understanding of HO upgrading in HCW with less coke. Image 1 • Hydrogen (H 2) production from hot compressed water (HCW) via partial oxidation of heavy oil was modeled by Aspen Plus software. • A sensitivity analysis was conducted to study the effect of the main operating parameters aimed to the H 2 production. • Experiments were conducted in order to track the results of simulation. • The most thermodynamic favorable operating conditions for upgrading heavy oil in HCW were identified. [ABSTRACT FROM AUTHOR]

The first part of the current study highlights the importance of developing a clean hydrogen supply chain (CHSC) in Iran to enhance energy security and contribute to global efforts towards sustainable energy transition. Depending on whether the focus is on domestic consumption or export of hydrogen, the study provides valuable insights into the prioritization of CHSC development pathways via multi-criteria decision-making tools (AHP, AHOP-TOPSIS, and AHP-VIKOR). The results show that for domestic hydrogen consumption (internal scenario), the best path of the supply chain includes blue hydrogen from steam methane reforming coupled with carbon capture and storage, H 2 -carriers (ammonia and methanol), natural gas grid for transportation and distribution, and industry sector as the end user. In the external scenario, however, the best path of the CHSC consists of green hydrogen production based on solar energy, and the other parts of the path include liquid hydrogen as the storage method, ship as the distribution and transportation, and industrial sector as the end user. By identifying the most suitable methods and technologies for each stage of the supply chain, this paper offers a comprehensive analysis that can guide decision-making in CHSC development. [ABSTRACT FROM AUTHOR]

Due to the increasing attention of the experts working in refineries on innovative techniques for heavy oil upgrading, the current research is focused on in-situ upgrading of heavy oil in supercritical water (SCW) assisted by formic acid. In dry condition, formic acid (FA) decomposes by two parallel paths, namely decarboxylation (HCOOH → H 2  + CO 2 ) and dehydration (HCOOH → CO + H 2 O) to produce hydrogen and carbon mono oxide, respectively. Water-gas shift (WGS) reaction which is taken place by SCW and carbon monoxide provides active hydrogen (AH) as a more favorable hydrogen source for upgrading heavy oil in SC condition. In the current study, first, thermodynamic simulation of FA decomposition in SCW was studied to evaluate the contribution of hydrogen from water in Aspen suite environment by performing sensitivity analysis. Here, the effects of operational parameters (temperature, pressure, FA to water ratio) were studied on the above-mentioned reaction. The simulation results as well as experimental data show that the increase of FA to water ratio (FA/W) enhances the contribution of dehydration path, which means that SC works better as a precursor of hydrogen due to the higher concentrations of CO at SC condition. In order to specify the portion of hydrogen from WGS and decarboxylation reaction, the isotope labeling technique was applied by replacing ordinary water (H 2 O) with heavy water (D 2 O) in SC condition in the presence of heavy oil and FA. After combining the experimental data and Hansen solubility parameter of water (δ H ), it was revealed that temperature has dual effects which can influence on coking reaction by physical and chemical reaction. It means that an increasing in temperature can suppress the coke formation due to better miscibility of oil with water, while at an extreme temperature condition (500 °C), the dominant condensations of polycyclic aromatics are conspicuous; consequently the rate of coking is enhanced. High pressures (∼45 MPa) also lead to the more coking reaction through the influence on the phase behavior of oil-water (δ H and AH%) in which asphaltene conversion path is converted to coke rather than light products. Accordingly, T = 450 °C and P w  = 27 MPa were proposed respectively as an appropriate temperature and pressure for heavy oil upgrading in supercritical water assisted by FA to cause less coke and produce more light liquid products. [ABSTRACT FROM AUTHOR]

In continuation of the previous part, this paper comprehensively focuses on energy, exergy, exergo-economic, and environmental (4E) analyses of two prioritized clean hydrogen (H 2) supply chains pathways. The first scenario relies on domestic demand , involves blue H 2 production and storage using steam methane reforming coupled with carbon capture and storage through H 2 conversion to hydrogen carriers in liquid form (ammonia and methanol) aligned with the existing infrastructure. The second scenario involves green H 2 production from photovoltaic panels as the power source follows by storing H 2 in liquid form which is more suitable to export. The findings indicate that the blue H 2 system outperforms the green H 2 system in terms of energy and exergy, boasting 41.38% and 22.15% compared to 12.16% and 12.75%, respectively. However, when examining economic parameters, the blue H 2 system shows a total cost rate of 1976 US$/h, a net profit of $747.2 million (mn) at the end of its lifetime, and a payback period of approximately nine years. Conversely, the green H 2 system demonstrates economic indicators of a 125.2 $/h as a total cost rate, $1.26 billion (bn) net profit, and an 8.17 year payback period. Moreover, the production cost rates for blue and green H 2 are 1.32 $/kg and 2.55 $/kg, respectively; while the CO 2 emissions rate in the blue H 2 system is 10.71 kg/s. The green H 2 system prevents 19.84 kg/s of CO 2 emissions resulted a significant environmental cost reduction of 2.28 $/kg H 2. This analysis facilitates a thorough comparison of these two clean H 2 production and storage systems, offering insights for policymakers across performance, economic, and environmental dimensions. • A comprehensive 4E analysis was applied for the selected H 2 value chain scenarios. • Blue H 2 scenario is superior economically while environmentally the green one takes precedence. • Carbon credit makes the green H 2 scenario emerges frontrunner utilizing PV solar technology. • Methanol was recognized as the most cost-effective H 2 carrier for storage in Iran. [ABSTRACT FROM AUTHOR]

The global imperative to transition from fossil fuels to renewable sources is addressed, with hydrogen identified as a pivotal energy carrier. Departing from qualitative approaches, quantitative methodologies are employed to understand the challenges comprehensively. Qualitative insights are quantitatively assessed through a novel index, enabling a nuanced analysis of strengths and weaknesses. The resulting model is a precise tool for informed decision-making in energy transition efforts. Notably, Chile, New Zealand, and Morocco are identified as high-potential economies for hydrogen development, aligning with expert opinions. Conflict demonstrates an overall negative correlation with technological progress, while regulatory quality emerges as a strong positive correlation with the state of hydrogen in policy. This quantitative model offers a robust framework for future research and application, including incorporating additional data and subnational-level analysis. The study provides a quantitative foundation for advancing hydrogen development and sustainable energy transition. • A numerical index can be beneficial to studying the ongoing energy transition. • We present a novel way of quantizing hydrogen development using various indicators. • Results show that there are several "hidden champions" with high growth potential. • Indicators based on varying dimensions of development offer a clear picture forward. [ABSTRACT FROM AUTHOR]

Due to the high protein content in algal species, these precursors require further catalytic removal of heteroatoms such as nitrogen, being upgraded to biofuels. In the current study, first, synthesis of Na + ZSM-5 nanocrystals with well-distribution in size was performed successfully with a novel technique in supercritical water. After converting to H + ZSM-5 type, it was applied for hydrodenitrogenation (HDN) of crude bio-oil, obtained from hydrothermal liquefaction (HTL) of chlorella sp. microalgae, in the presence of high temperature water and formic acid (HCOOH) mixture. The effects of reaction temperature (250–500 °C), formic acid as a source of in-situ hydrogen, and nano-catalyst (compared with industrial type) on nitrogen elimination and H/C ratio were investigated comprehensively. Compared with non-catalytic upgrading conditions, a substantial amount of nitrogen removal was obtained in the presence of nano-catalyst and formic acid with the maximum amount of 75 wt% at 400 °C in comparison with the macron-size industrial catalyst (54 wt%) at the same temperature. Due to more miscibility and consequently high degree of liquid fuel recovery (Y liq ) with less coking as well as more HDN, T = 400 °C was chosen as the optimum temperature. Furthermore, H/C ratio of upgraded bio-oil, as an index of aromatization, had similar trend which indicates that in the presence of H + ZSM-5, higher temperature is more favorable to aromatization than cracking which makes HDN more difficult. In the absence of a catalyst, H/C ratio showed no substantial trend with temperature which demonstrates the significance of H + ZSM-5 catalyst for cracking. [ABSTRACT FROM AUTHOR]

In the light of the novel physical-chemical properties of supercritical water as a green reaction medium, we studied the synthesis of deuterated benzene in supercritical heavy water, in the presence of sodium deutroxide, as a catalyst. The effects of operational parameters including temperature, time, pressure (density), catalyst amount and benzene/D 2 O volumetric ratio on the degree of deuteriation (D%) and deuterated benzene yield were investigated extensively and the conditions for the highest degree of deuteration and product yield, were optimized. Furthermore, because of the importance of the pressure of solution inside the reaction medium on the H/D exchange process as well as the impurity production, which have not been studied thoroughly, estimation of density for the benzene-water mixture under these operational conditions was studied with Aspen software. After comparing with the experimental data, the best equation of state, Soave-Redlich-Kwong with Kabadi-Danner modification (SRK-KD), with lowest amount of temperature-averaged [350 °C–400 °C] deviation was introduced. [ABSTRACT FROM AUTHOR]

Catalytic cracking of bottom product from the vacuum distillation unit, i.e., vacuum residue (VR) was investigated in supercritical water (SCW) over different forms of iron oxide nano-catalyst as free α-Fe 2 O 3 nanoparticles and SiO 2 -supported α-Fe 2 O 3 crystals. The effects of operational parameters including reaction temperature, reaction time, catalyst to oil weight ratio, and water to oil weight ratio were studied on the yield of maltene and coke produced from VR cracking as well as asphaltene conversion, in a batch autoclave reactor. SEM, XRD and TGA analyses were used to characterize the catalyst before and after the reaction. TGA and XRD images confirmed phase transformation of α-Fe 2 O 3 to magnetite (Fe 3 O 4 ) during reaction with free nanoparticles, and SEM images showed agglomeration of the nanoparticles significantly. It was resulted that silica-supported α-Fe 2 O 3 catalyst was more stable and more effective than that of free nanoparticles in the process of VR cracking. The suggested mechanism of the reaction would be a cycle beginning with oxidative cracking of hydrocarbons by the lattice oxygen provided from reduction of α-Fe 2 O 3 to Fe 3 O 4 then releasing the active hydrogen by SCW gas shift reaction to hydrocracking VR and production of aliphatic compounds. At the same time, the reduced form of the catalyst (Fe 3 O 4 ) would be converted to α-Fe 2 O 3 by the oxygen atom released from SCW. [ABSTRACT FROM AUTHOR]

• This study reflects the effects of HVAC controlling by occupant behavior and IoT windows with seven scenarios. • Influence of various climates, g-value and orientations have been investigated. • 8.9–27% of energy saving have been achieved in seven climates (based on IRC) in USA. • Results show that this method is more effective environmentally and economically in fifth, sixth and seventh scenarios. The residential sector emits a substantial portion of greenhouse gasses. Heating and cooling account for a significant part of this emission, therefore energy-saving strategies for this part are vital. This study aims to investigate the effect of the IoT windows on heating and cooling load with designing a novel window that can change its g-value with a smart mid-shade. This study analyzes various situations of HVAC devices control strategies (comparison between a conventional thermostat and thermostat by occupant behavior control) and distinct window scenarios (comparison of different g-value of IoT window with a conventional window) in seven different climate zones for a one-story dwelling in the United States. Simulation has been done by EnergyPlus and Window software. For more reliable results, all the situations are simulated in four different directions. The analysis reveals the best scenarios based on energy saving of annual energy consumption for seven locations as following: 8.9% in Honolulu (Hawaii), 20.8% in Leon (Florida), 27% in Los Angeles (California), 26.3% in Bernalillo (New Mexico), 20.7% in Sangamon (Illinois), 19.5% in Sullivan (New York) and 17.8% in Itasca (Minnesota). Finally, the best scenario is simulated for each city based on economic and environmental indicators (the amount of CO 2 emitted). [Display omitted] [ABSTRACT FROM AUTHOR]

All economies need energy for growth, particularly emerging ones with continued demand for fossil fuels that move them to unconventional energy sources such as heavy oil. However, the presence of large quantities of heteroatoms -sulfur, nitrogen, oxygen, and metals – in heavy oil is a major contributor to environmental pollution during the combustion phase. This requires the crude and residue to be upgraded and fractionated within tight specifications. Hot compressed water (HCW), at or beyond the critical point (374 °C, 22.1 MPa), has emerged as a highly promising environmentally benign and efficient method for heavy oil upgrading to replace conventional toxic solvents. The synergistic effect of HCW with energy generated from renewable sources is a new avenue into a cleaner carbon energy system for fuel production with the benefits of reduced energy consumption and lower carbon dioxide emission. This paper provides a comprehensive review in multi-scale which underlines the recent evolution and the challenges in this field. In addition, the critical factors and emerging gaps influencing the heavy oil upgrading in HCW are appended. Eventually, a set of suggestions for integrating renewable energy technologies with heavy oil upgrading in HCW and future perspective has been reported. [Display omitted] • The synergistic effect between HCW and heavy oil as a cleaner carbon conversion system is reviewed. • A comprehensive view in multi-scale which underlines the recent evolution and the challenges in this field. • Critical factors and emerging gaps influencing the heavy oil upgrading in HCW are appended. • A logical integration of renewable technologies with carbon-based energy conversion system in HCW is suggested. • Possible research suggestions and directions on this field have been proposed. [ABSTRACT FROM AUTHOR]

Carbon dioxide utilization (CDU) is one of the most critical approaches in climate change control. CDU's future depends on the future demand for carbon-derived products; among them, formic acid is an excellent candidate due to its distinctive characteristics as a hydrogen carrier in liquid form. It is non-toxic that can be used in hydrogen fuel cells, and its significant potential in the heavy oil and biofuel refining process as a hydrogen-carrier substance. This research aims to use Energy, Exergy, Exergoeconomic, and exergoenvironmental (4E) analysis to evaluate the impact of anolyte material on the efficiency of the electrochemical reduction process to synthesis formic acid (in the term of six new anolyte materials). Results show that the second scenario (IrO 2 single circulation mode) is the best option for the power plant. Implementing this CDU system reduces the carbon capture of about 75.20 kg/s or about 89% of the power plant's overall carbon emission. This process's energy penalty can be adequately provided by the PV, which causes greater exergy efficiency and decreases the power plant's energy performance rate. Moreover, the use of IrO 2 anolyte is decreased the exergy rate cost and the flow rate cost to the 0.21 $/kWh and 2.280×10-2 $/s. The CDU's investment cost using the DSA/O 2 anolyte is 28% decreased compared to the KOH anolyte and reached 7.2 million USD for the CO 2 utilization plant. [Display omitted] • Iran is the 8th Carbon dioxide producer in the world with great potential for carbon capture. • CDU is an option to be combined with the carbon capture process to reuse the Carbon emission. • In this paper, six anolyte for the ER process are compared, and the IrO 2 is selected as the best option. • Implementing the IrO 2 on the ER process results in 89% of emission reduction and also producing 79.7 kg/s formic acid. • Considering the capability of the FA as a hydrogen carrier and Heavy oil refining material, this product can be used in the petrochemical refineries. [ABSTRACT FROM AUTHOR]

For clean upgrading of heavy oil, catalytic treatment in supercritical water (SC-H 2 O) is known as an attractive green methodology. To gain quantitative and qualitative insights of heavy oil upgrading in SC-H 2 O, optimization of operating conditions was performed where higher heating value (HHV), low sulfur contents as well as low rate of coke formation are desirable. A series of experiments for upgrading the vacuum residue (VR) feed in SC-H 2 O were designed with response surface methodology (RSM) and performed in presence of formic acid and hematite iron oxide nanoparticles as hydrogen donor and catalyst, respectively. The key process parameters including temperature, water, formic acid, catalyst contents and reaction time were optimized by the mentioned statistical methodology. The proposed optimization model displayed an acceptable correlation between the predicted and experimental results. From the experimental results it was apparent the incorporation of hematite nanoparticles with SC-H 2 O and formic acid exhibited higher degree of light fraction product and low coke formation derived from oxygen vacancy and better catalyst reducibility in SC-H 2 O. [ABSTRACT FROM AUTHOR]

This paper describes a new synthetic method to prepare a composite of metal oxide nanoparticles and zeolite (Fe-ZSM-5) in hot compressed water. Two approaches, one-pot immobilization of iron oxide on ZSM-5 and post-ZSM-5-synthesis iron oxide impregnation are studied. The products show various morphologies, which lead to different activities during the selective catalytic reduction of NO with NH 3. In the first approach, Fe-ZSM-5 is synthesized in hot compressed water from precursors with various concentrations of Fe(NO 3) 3 , while in the second route, firstly, ZSM-5 powder is prepared and then impregnated with iron oxide. The state of Fe in Fe-ZSM-5 was studied through TEM, XPS, XRD, NH 3 -TPD, and H 2 -TPR. Both methods result in the production of highly dispersed iron species, however, Fe-ZSM-5 prepared from the one-pot synthesis method contains more acidic sites and more reducible iron species because of the presence of FeO x nanoparticles mainly in the intra-framework of the zeolite. Furthermore, it is observed that the increase in iron concentration in the precursor has an adverse effect on the surface area and acidity of the final Fe-ZSM-5 product. On the other hand, Fe-ZSM-5 obtained from the impregnation process contains higher quantities of iron in the extra-framework position in the form of bulky aggregates with lower activity. Consequently, Fe-ZSM-5 synthesized through the one-pot route showed higher activity because of the well dispersive iron oxide in the zeolite support. The highly dispersive state is attributed to the predominant presence of iron bound to the framework of aluminum in the zeolite. The results also show that the protonation of the catalyst has no crucial effect on the activity of the catalyst, while the oxidation state of iron oxide is greatly responsible for the SCR activity of the catalyst. Image 1 • Novel synthesis of nano Fe-ZSM-5 in hot compressed water. • One-pot immobilization route shows higher activity than post-synthetic impregnation in NH 3 -SCR of NO. • Isolated iron oxide in intra-framework of zeolite is responsible for higher activity of catalyst. [ABSTRACT FROM AUTHOR]

• Isotope tracing technique was applied to study the role of HCW as an active H-donor for hydrogenation of PAHs. • Compared to lone HCW, addition of formic acid and iron oxide NPs displays superior activity in hydrogenation of PAHs. • Hydrogenation from HCW only cape the double-bond carbon which belongs to the PAHs rings (C H), instead of single-bond carbon (C H). • The mechanisms of contribution of HCW during the conversion of PAHs were described. Use of hot compressed water (HCW) as a reaction medium to enhance conversion efficiency of polyaromatic hydrocarbons (PAHs) to lighter products is an important topic in green chemistry, where hydrogenation and ring opening of PAHs are crucial for tar removal and heavy oil upgrading with less coke. In this study, the influence of HCW on the conversion of coronene (super benzene) as model molecule of PAHs with 7-ring is examined. A series of agents, such as cheap iron oxide NPs (α-Fe 2 O 3) as an oxygen-donor, formic acid (CHOOH) as hydrogen-donor, and their physical mixtures, are used. Pure deuterium oxide (D 2 O) is also applied instead of H 2 O to track the hydrogenation from HCW. The influences of water density; reaction temperature, reaction time, and amount of catalyst loading on conversion of coronene and yield of coke are studied. The reaction in the presence of D 2 O as control experiment shows minor H/D exchange during the reaction process stating that water itself has no effect on hydrogenation of coronene. In the presence of agents (iron oxide, formic acid and their mix), however, outstanding synergistic effect occurs and water could be used as a green and efficient medium for hydrogenation and enhancing the conversion of coronene. In summary, the isotope tracing experiments reveals that hydrogenation from HCW only cape the double-bond carbon which belongs to the PAHs rings (C H), instead of hydrogenation of created alkyl groups with single-bond carbon (C H). This issue indicates the strong impact of active hydrogen from condensation reaction on hydrogenation of PAHs, which elaborated at the cost of made coke. [ABSTRACT FROM AUTHOR]

The fatty acid methyl esters (FAMEs) and H 2 were produced from sesame cake in supercritical mixture of methanol and water using alumina supported CaO and MgO nanoparticles. The fresh and used catalysts were characterized by ICP-OES, BET, XRD, and TEM techniques. The significant influence of catalysts on the gas production was revealed. Further, the highest amounts of H 2 , CO, and CO 2 was achieved by MgO/γ-Al 2 O 3 with the hydrogen fraction more than 7.6 times, compared with the non-catalytic process. For biodiesel, CaO/γ-Al 2 O 3 showed the best performance where 35.3% of the liquid product was FAMEs, more than 2.3 times relative to the non-catalytic process. In order to reduce the amounts of nitrogenate content in the liquid fuel, an efficient and scalable method implemented with the Soxhlet apparatus and the absorption tube equipped with CO 2 gas flow system. Accordingly, the N-contents of the liquid products were reduced to highest degree of 65.2%, asserting that the reduced amount of the N-content strongly depends on the catalyst during the production process. • One-pot biodiesel production from sesame cake in supercritical methanol using water as co-solvent. • Upgrading of biodiesel with reducing nitrogenates using a method by CO 2 gas flow. • Comparison of the process in the presence of γ-Al 2 O 3 , CaO/γ-Al 2 O 3 , and MgO/γ-Al 2 O 3. • Comparison of H 2 , FAMEs, Oxygenates, Hydrocarbons, and Nitrogenates of products. [ABSTRACT FROM AUTHOR]

• Propose a new sustainable system integrated with geothermal energy, consisting of upgrading heavy oil in hot compressed water and generating electricity. • Multi-objective optimization using genetic algorithms based on artificial neural networks. • Exergy efficiency and total cost rate of the optimal point system are 23.85% and 2.62$/s, respectively. • The effect of geothermal energy on reducing the cost of CO 2 emission by 11.5 M$/year. • Desulfurization in this system prevents 177.86 kton/year of SO 2 emission. In this study, a combined cycle of geothermal energy and heavy oil upgrading in hot compressed water (HCW) is investigated for electricity generation. The proposed approach offers efficient desulfurization and reduced carbon dioxide emissions, as renewable energy supplies part of the energy needed for the upgrading process. The performance of the superstructure is analyzed through energy, exergy, economic, exergoeconomic analysis and environmental assessments, revealing improvements in cycle exergy efficiency (21.67%) and total system cost rate (3.79 $/s). Additionally, a multi-objective optimization of the system is conducted using artificial neural network coupled with genetic algorithm, resulting in optimal values of 23.85% for cycle exergy efficiency and 2.62 $/s for total system cost rate. The integration of geothermal energy in this system leads to a reduction of global carbon dioxide emissions by 479.16 kton/year, resulting in savings of approximately 11.5 M$/year in environmental costs. Finally, a case study demonstrates a mitigation of local sulfur dioxide emissions caused by heavy oil consumption by approximately 177.86 kton/year. [ABSTRACT FROM AUTHOR]

Due to exhaustibility of fossil fuels and their adverse effects on the environment, bio-oil has been considered as an alternative energy source for fuel applications. Currently, there are two main processes for bio-oil production: pyrolysis and hydrothermal liquefaction (HTL). The hydrothermal liquefaction is defined as biomass-to-liquid conversion route carried out in the hot compressed water with or without the presence of a catalyst. The major concern in HTL is the high pressure of the process which results in high capital cost of equipment. Thus, the process pressure and temperature should be reduced, but at a lower temperature, bio-oil yield is not high enough to make HTL an economical process for sustainable fuel production. In this research, we investigated the applicability of a nanocatalyst (nano-Ni/SiO 2 ), an acid catalyst (synthesized zeolite), and an alkali catalyst (Na 2 CO 3 ) to increase the bio-oil yield at low temperatures (210 °C, 230 °C, 250 °C). The major result of this work was higher bio-oil yields with the order of nano-Ni/SiO 2 > zeolite > Na 2 CO 3 in hydrothermal liquefaction of microalgae Nannochloropsis sp.. The highest bio-oil yield (30.0 wt%) was obtained at 250 °C by using Nano-Ni/SiO 2 . Moreover, applying catalyst resulted in a decrease in the oxygen and the nitrogen contents of the bio-oil and consequently an increase in its heating value. The results of this research also suggest the possibility of nanocatalyst recovery for 2–3 times. [ABSTRACT FROM AUTHOR]

In this study, the usage and comparison of two approaches comprising (1) geothermal energy (GE) system and (2) combined heat and power system with reciprocating engine (CHPRE) as a driver, is investigated in distinctive scenarios to provide heat demands of anaerobic digestion process. To make a precise analysis, a collection of reasonable assumptions, data analysis, and simulations have been conducted to find out the scale of the power plants whether geothermal energy is a proper approach to be utilized for heating purposes in the anaerobic digestion process. This study presents a comprehensive analysis which contains various cases of study ranging from electricity production to economic issues. Results of the analysis have proved that although the GE approach has some downsides, it is widely favorable to CHPRE approach through some of the subjects of analysis. Applying the GE approach for heat demands of anaerobic digestion saves a considerable portion of biogas, which ranges from 22% to 24.8% of the produced biogas in digesters. Another important discovery is that usage of the GE approach results in a reduction of greenhouse gases emissions up to 66%. Moreover, financial results indicate that the usage of GE mitigates the initial costs of an anaerobic digestion unit ranging between 23% and 25% based on the scenarios. GE approach is also more economical as the power plant of anaerobic digestion since it has less discounted payback period than the CHPRE approach, and this advantage is between 11 and 47 years depending on the scenarios from both methods. • Usage of geothermal power plant as the way for heating for anaerobic digestion. • Comparing geothermal power plant to biogas based combined heat and power reciprocating engines for heating. • Better biogas management by saving up to 25% of the produced biogas. • Reducing greenhouse gas emissions of anaerobic digestion up to 66%. • Total capital investments of anaerobic digestion reduce up to 25%. [ABSTRACT FROM AUTHOR]