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Abstract Aquatic biomass is promising due to its high productivity in less nutrient environment. Gasification is one of the frontier technologies to convert biomass into energy, mainly to produce electricity. Recent development in electrochemical technologies allows the utilization of electricity to upgrade waste CO2 into chemical products. In the present study, the performance of integrated gasification and electrolyzer is evaluated. The gasification converts biomass into syngas and electricity, while the electrolyzer convert CO2 from the gasification residue into chemicals such as CO and methanol by utilizing the electric power from the gasification. The variation of the gasifying agent flow rate (O2 equivalence ratio between 0.36 and 1.00) provides the variation of syngas composition (H2: 28–65%; CO: 25–43%) and heating value (12–30 MJ/kg). The production of CO or methanol is significantly influenced by O2 equivalence ratio and fraction of syngas into power generator. The highest exergy loss is found to be in the cooling system. The net CO2 emission of the proposed configuration is negative (−0.09 to −0.17 kg CO2/GJ at O2 equivalence ratio of 0.36) by considering the CO2 consumption of the biomass feed. Therefore, this system is promising for further investigation as the future renewable technology for energy conversion.

Abstract The Maisotsenko cycle (M-cycle), which is a dew-point air-cooling system, has been identified as a promising alternative to conventional air conditioning systems. Previous works have focused on conducting feasibility studies of using the M-cycle in various applications in different climates while the optimization of the process and the impact of important design and operational aspects received few interests. In the present work, the impacts of various geometrical and operational aspects on the M-cycle performance were theoretically investigated. Six configurations of the counter-flow M-cycle were studied and compared numerically. These configurations included a circle, a rectangle with different aspect ratios (width-to-height ratio), and a triangle with various angles. In the circle and triangle configurations, the dry and wet channels were considered to be concentric, where the dry channel was surrounded by the wet channel. However, the plates were put on each other in rectangular geometries. A heat and mass transfer model of the counter-flow M-cycle was developed and validated using the previous numerical and experimental results of Riangvilaikul and Kumar. The influences of the hydraulic diameter and the length of the channel were investigated. Furthermore, the impacts of operating conditions, such as intake air temperature, intake relative humidity, intake air velocity, and water temperature, on the overall M-cycle performance were also examined. The system's performance was expressed in terms of dew-point effectiveness, wet-bulb effectiveness, coefficient of performance, cooling capacity, and water consumption. The obtained results show that it is preferable to maintain the intake air velocity between 2 and 3 m/s for all the considered cases. The triangular geometry with a 60° angle appears to be the best geometry. In addition, the circular shape was found to be preferable to the rectangular geometries.

Abstract Productivity prediction and energy evaluation can reduce the economic risk of hydrate development. Meanwhile, the study of conventional resources provides useful reference and guidance. Therefore, this paper aims to establish Inflow Performance Relationship (IPR) formulas for the multiphase, non-isothermal flow in Class III methane hydrate deposits. The production process is divided into ascent and decline stage based on production characteristics. Fetkovich’s formula and Vogel’s formula are selected respectively for these stages. To revise these formulas, new index and pressure value are introduced to reflect the complexity and variability of hydrate production. New index called pseudo-pressure describes the compound effect of multi-driven forces. New value of minimum production pressure can avoid the adverse impact of ice block. Coefficients in these formulas are quantitatively characterized by selected key factors. The coefficient in Fetkovich’s formula is characterized by layer thickness and gas flowablity. The coefficient in Vogel’s formula is characterized by hydrate saturation, layer thickness and salinity. The verified results indicate that the average errors of the revised Fetkovich’s formula is around 8% and under 11% for the revised Vogel’s formula. This means these revised IPR formulas can provide guidance for the productivity prediction and evaluation of Class III methane hydrate deposits.

Gastric ulcer (GU) is the most common and chronic inflammatory condition mediated by multiple immune cells like neutrophils, macrophages, and lymphocytes with multiple pro-inflammatory cytokine interleukins such as IL-8, IL-10, IL-β, and interferon-γ (IFN-γ). Copper (Cu) is one of the essential micronutrients mainly found in the liver and brain. It plays a major role in metabolism, enzyme conversion, free radical scavenging, trafficking agents, and many others. Due to its various roles in the biological system, it can also be used as a therapeutic agent in many diseases like colon cancer, bone fracture healing, angiogenesis, as an antibacterial, wound-healing and radiotherapeutic agents. In this study, we used thiol-functionalized cellulose-conjugated copper-oxide nanoparticles (CuI/IIO NPs) synthesized under environmentally friendly conditions. We have evaluated the effects of cellulose-conjugated CuI/IIO NPs against ethanol-induced gastric ulcer in Wistar rats. The cellulose-conjugated CuI/IIO NPs were evaluated against different physical, histochemical, and inflammatory parameters. The NPs promoted mucosal healing by ameliorating ulcerative damage, restoring the histoarchitecture of gastric mucosa, and inhibiting pro-inflammatory cytokines such as tumor necrosis factor-α (TNF-α), interleukin-1 beta (IL-1β), and other inflammatory biomarkers such as myeloperoxidase (MPO) activity and nitric oxide (NO) levels. The current study's findings suggest that cellulose-conjugated CuI/IIO NPs exerted antiulcer effects on the preclinical rat model and have promising potential as a novel therapeutic agent for the treatment of gastric ulcers.

Due to the depletion of traditional energy resources, emissions of greenhouse gases, climate change, etc., renewable energy resources (RER) based power generation is becoming the main source of the present and future power sector. The major RERs, including solar, wind, and small hydro, may provide reliable and sustainable solutions in the smart grid environment. Solar and wind energy-based power generation is more prevalent but varies in nature and is not even very predictable very efficiently. Therefore, it has become necessary to integrate two or more RER and develop a hybrid energy system (HES). The HESs provide a cost-effective and reliable power supply with reduced and/or almost negligible greenhouse gas emissions as well. Due to economic and power reliability concerns, the optimal sizing of components is necessary for the development of an optimum HES. In recent years, metaheuristic evolutionary algorithms have been widely used for optimal sizing of HES. Harris hawk’s optimizer (HHO) is a recently devised metaheuristics search method that has the ability to discover global minima and maxima. However, due to its weak exploitation capacity, the basic HHO algorithm’s local search is pretty slow and has a slow rate of convergence. Thus, to boost the exploitation phase of HHO, a new approach, random exploratory search centered Harris hawk’s optimizer (hHHO-ES), has been developed in the present work for optimal sizing of HES. The suggested approach is validated and compared to existing optimization approaches for a variety of well-known benchmark functions, including unimodal, multimodal, and fixed dimensions. Following this, it is used to develop HES, which will be capable of providing power to remote areas where grid supply is scarce. The objective function is formulated using net present cost (NPC) as a prime function under a set of constraints such as bounds of system components and reliability. The obtained results are compared with those from harmony search (HS) and particle swarm optimization (PSO) and found to be better.

As the price of renewable electricity continues to plummet, hydrogen (H₂) production via water electrolysis is gaining momentum globally as a route to decarbonize our energy systems. The requirement of high purity water for electrolysis as well as the widespread availability of seawater have led significant research efforts in developing direct seawater electrolysis technology for H₂ production. In this Perspective, we critically assess the broad-brush arguments on the research and development (R&D) needs for direct seawater electrolysis from energy, cost and environmental aspects. We focus in particular on a process consisting of sea water reverse osmosis (SWRO) coupled to proton exchange membrane (PEM) electrolysis. Our analysis reveals there are limited economic and environmental incentives of pursuing R&D on today’s nascent direct seawater electrolysis technology. As commercial water electrolysis requires significant amount of energy compared to SWRO, the capital and operating costs of SWRO are found to be negligible. This leads to an insignificant increase in levelized cost of H₂ (<0.1 $/kg H₂) and CO₂ emissions (<0.1%) from a SWRO-PEM coupled process. Our analysis poses the questions: what is the future promise of direct seawater electrolysis? With an urgent need to decarbonize our energy systems, should we consider realigning our research investments? We conclude with a forward-looking perspective on future R&D priorities in desalination and electrolysis technologies.

Static VAr compensators (SVC) are used for voltage control of long distance bulk power transmission lines. By using a supplemental control loop an SVC can also be used to improve the dynamic and transient stability of a power system. Use of a self-tuning adaptive control algorithm as a supplementary controller for the SVC is presented in this article. The control derived is based on a pole-shifting technique employing a predicted plant model. Simulation studies on a simple power system model showed rapid convergence of the estimated plant parameters with an extremely good damping profile. The controller has been tested for ranges of operating conditions and for various disturbances. The effectiveness of the adaptive damping controller was also evaluated through an ‘optimized’ PI controller.

Changing market demand and increasing environmental regulations challenge the refining industry to shift crude slates and reconfigure production processes while reducing emissions. Yet sellers and buyers remain unaware of the carbon footprint of individual marketable networks, and each crude oil has different specifications and is processed in different destination markets. Here we show the global refining carbon intensity at country level and crude level are 13.9–62.1 kg of CO2-equivalent (CO2e) per barrel and 10.1–72.1 kgCO2e per barrel, respectively, with a volume-weighted average of 40.7 kgCO2e per barrel (equivalent to 7.3 gCO2e MJ−1) and energy use of 606 MJ per barrel. We used bottom-up engineering-based refinery modelling on crude oils representing 93% of 2015 global refining throughput. On the basis of projected oil consumption under 2 °C scenarios, the industry could save 56–79 GtCO2e to 2100 by targeting primary emission sources. These results provide guidance on climate-sensitive refining choices and future investment in emissions mitigation technologies. The carbon footprint of oil refining differs depending on crude oil quality and refinery configuration. Analysis of global oil refining in 2015 shows refining carbon intensity at crude, refinery and country levels and highlights potential for emissions reductions.