Three types of organic Rankine cycles (ORCs): basic ORC (BORC), ORC with single regeneration (SRORC) and ORC with double regeneration (DRORC) under the same heat source have been simulated in this study. In the following, the energy and exergy analysis and the advanced exergy analysis of these three cycles have been performed and compared. With a conventional exergy analysis, researchers can just evaluate the performance of components separately to find the one with the highest amount of exergy destruction. Advanced analysis divides the exergy destruction rate into unavoidable and avoidable, as well as endogenous and exogenous, parts. This helps designers find more data about the effect of each component on other components and the real potential of each component to improve its efficiency. The results of the advanced exergy analysis illustrate that regenerative ORCs have high potential for reducing irreversibilities compared with BORC. Total exergy destruction rates of 4.13 kW (47%) a... [more]

The reverse osmosis (RO) process is one of the best desalination methods, using membranes to reject several impurities from seawater and brackish water. To systematically perceive the transport phenomena of solvent and solutes via the membrane texture, several mathematical models have been developed. To date, a large number of simulation and optimisation studies have been achieved to gauge the influence of control variables on the performance indexes, to adjust the key variables at optimum values, and to realise the optimum production indexes. This paper delivers an intensive review of the successful models of the RO process and both simulation and optimisation studies carried out on the basis of the models developed. In general, this paper investigates the scope and limitations of the RO process, as well as proving the maturity of the associated perspective methodologies.

Compared with conventional natural gas, liquefied natural gas has the advantages of easier storage and transportation, more safety, less indirect investment, better peak regulation, and environmental protection. This paper studies the large-scale cryogenic propane precooled mixed refrigerant (C3MR) liquefied natural gas (LNG) process. The phase equilibrium of the liquefaction process is calculated by the Peng-Robinsonstate equation using ASPEN. A numerical model for the thermal process simulation of the liquefaction process is established by MATLAB. Based on Active X technology, data invocation between software is realized, which overcomes the problem of process variable changes under limited degrees of freedom. The minimum sum of the propane precooling amount for the compressor energy consumption is used as the objective function, the control variate method is used to address the liquefaction process model, and the parameter sensitivity analysis is performed and combined with the exer... [more]

Hydrogen purification and CO2 capture are of great significance in refineries and pre-combustion power plants. A dual membrane separator offers an alternative approach for improving H2/CO2 separation efficiency. In this work, H2/CO2/CH4 ternary gas mixtures separation can be achieved by a dual membrane separator with an integrated polyimide (PI) membrane and polydimethylsiloxane/polyetherimide (PDMS/PEI) composite membrane. A hollow fiber dual membrane separation equipment is designed and manufactured. Through the self-designed device, the effects of stage cut, operating temperature, operating pressure, and membrane area ratio on separation performance of dual membrane separator have been studied. The results indicate that, at a high stage cut, a dual membrane separator has obvious advantages over a single membrane separator. Operating temperature has a significant impact on gas permeation rates. At 25 °C, a dual membrane separator can obtain the highest purity of H2 and CO2. By increa... [more]

This paper explores a possible waste-based economy transition strategy. Digestate from the organic fraction of municipal solid waste (OFMSW) is considered, as well as a low-added value product to be properly valorized. In this regard, air gasification may be used to produce syngas. In this work, the production of methanol, hydrogen, or electricity from digestate-derived syngas was assessed by ChemCAD process simulation software. The process scheme of methanol production comprises the following parts: water gas shift (WGS) with carbon capture and storage units (CCS), methanol synthesis, and methanol purification. In the case of hydrogen production, after WGS-CCS, hydrogen was purified from residual nitrogen by pressure swing absorption (PSA). Finally, for electricity production, the digestate-derived syngas was used as fuel in an internal combustion engine. The main objective of this work is to compare the proposed scenarios in terms of CO2 emission intensity and the effect of CO2 stora... [more]

In nature bio-composites such as nacre show remarkable mechanical properties due to their complex hierarchical structure and high-volume fraction of its hard component. These composites are highly interesting for structural applications in different branches of industries for mechanical engineering and process technology. The aim of this work was to provide a scalable method for the production of highly filled composites by mimicking the structure of bio-composites. Therefore, composites from iron oxide (Fe2O3) and SBC-polymer (styrene-butadiene block copolymer) were fabricated by using a miniaturized spouted bed with an innovative fluidization gap design. Small iron oxide particles (25−45 μm) were fluidized in the spouted bed and coated with a polymer solution via a bottom spray nozzle. Afterwards the coated granules were hot-pressed and the mechanical properties of the obtained composites were tested. By this method composites with a bending strength of up to 6 MPa were fabricated. A... [more]

PET/PTT bicomponent filaments yarn is produced by two polymers: the polyethylene terephthalate (PET) and the polytrimethylene terephtalate (PTT) extruded side by side. This yarn is known for its high mechanical properties in particular elasticity and elastic recovery. However, differences between physical and chemical properties of the two components make the dyeing step of this yarn complicated. The aim of this work is the development of a dyeing process for bicomponent filaments without altering their physical and chemical properties. Different techniques such as SEM, FTIR, and differential scanning calorimetry (DSC) were used to characterize the studied yarn. For dyeing, three different disperse dyes CI Disperse Red 167.1, CI Disperse Yellow 211, and CI Disperse Red 60 with different energy classes were studied. The influence of dyeing conditions in particular dyeing temperature, pH of dye bath, dyeing time, and carrier concentration in the dye bath was evaluated. Responses analyzed... [more]

Poultry litter is one type of biomass and waste generated from the farming process. This study performed a performance and process analysis of poultry litter to energy using the lab-scale shell and tube heat exchanger (STHE) system along with a Stirling engine and a swirling fluidized bed combustor (SFBC). The effects of tube shape, flow direction, and water flow rates on water and trailer temperature changes were investigated during the poultry litter co-combustion process. Energy flow analysis and emissions were also studied. Results showed that the water outlet temperature of 62.8 ° C in the twisted tube was higher than the straight tube case (58.3 ° C ) after 130 min of the co-combustion process. It was found that the counter-current direction had higher water temperature changes, higher logarithmic mean temperature difference (LMTD), and higher trailer temperature changes than the co-current direction. A water flow rate of 4.54 L/min showed adequate heat absorption... [more]

Coal continues to dominate in the structure of the heat production system in some European countries. Coal-fired boilers in district heating and power generation systems are accompanied by the formation of large quantities of slag and ash. Due to considerable high temperature, slag may be used as a source of waste energy. In this study, the technical possibilities of recovery slag’s physical enthalpy from grate-fired district heating boiler of 45 MW thermal capacity are analyzed. The aim of the work is to estimate the waste energy potential of the slag in analyzed boiler and proposition of the heat recovery system. The construction and design of the existing deslagging system was examined. Studies have shown that high water temperature accelerates system wear. Recovering heat from this system decreases the water temperature, which extends the trouble-free working time. The slag parameters were determined, including the temperature at the outlet of the boiler and the temperature after l... [more]

The aim of this paper is to conduct a generalised assessment of both optimal working fluids and radial turbine designs for small-scale organic Rankine cycle (ORC) systems across a range of heat-source temperatures. The former has been achieved by coupling a thermodynamic model of subcritical, non-recperated cycles with the Peng⁻Robinson equation of state, and optimising the working-fluid and cycle parameters for heat-source temperatures ranging between 80 ° C and 360 ° C . The critical temperature of the working fluid is found to be an important parameter governing working-fluid selection. Moreover, a linear correlation between heat-source temperature and the optimal critical temperature that achieves maximum power output has been found for heat-source temperatures below 300 ° C ( T cr = 0.830 T hi + 41.27 ). This correlation has been validated against cycle calculations completed for nine predefined working fluids using both the Peng⁻Robinson equation... [more]

Hybridization of Waste to Energy (WtE) plants with solar facilities can take competing energy technologies and make them complementary. However, realizing the benefits of the solar integration requires careful consideration of its efficiency. To analyse such systems from the point of view of resource efficiency, the pure energy analysis is not sufficient since the quality of particular energy carriers is not evaluated. This work applies the exergo-ecological analysis using the concepts of thermoecological cost (TEC) and exergy cost for the performance evaluation of an integrated Solar-Waste to Energy plant scheme, where solar energy is used for steam superheating. Different plant layouts, considering several design steam parameters as well as different solar system configurations, in terms of area of heliostats and size of the thermal storage tank, were studied. The results for the solar integrated plant scheme were compared with the scenarios where superheating is performed fully by a... [more]

Oxy-fuel combustion is one of the most promising methods for CO₂ capture and storage (CCS) but the operating costs—mainly due to the need for oxygen production—usually lead to an obvious decrease in power generation efficiency. An “oxy-enrich combustion” process was proposed in this study to improve the efficiency of the oxy-fuel combustion process. The oxidizer for oxy-enrich combustion was composed of pure oxygen, air and recycled flue gas. Thus, the CO₂ concentration in the flue gas decreased to 30⁻40%. The PSA (pressure swing adsorption), which has been widely used for CO₂ removal from the shifting gases of ammonia synthesis in China, was applied to capture CO₂ during oxy-enrich combustion. The technological economics of oxy-enrich combustion with PSA was calculated and compared to that of oxy-fuel combustion. The results indicated that, compared with oxy-fuel combustion: (1) the oxy-enrich combustion has fewer capital and operating costs for the ASU (air separation unit) and the r... [more]

The integration of renewable energies into combined cooling, heating, and power (CCHP) systems has become increasingly popular in recent years. However, the optimization of renewable energies integrated CCHP (RECCHP) systems (i.e., optimal component configurations) is far from being well addressed, especially in isolated mode. This study aims to fill this research gap. A multi-objective optimization model characterizing the system reliability, system cost, and environmental sustainability is constructed. In this model, the objectives include minimization of annual total cost (ATC), carbon dioxide emission (CDE), and loss of energy supply probability (LESP). The decision variables representing the configuration of the RECCHP system include the number of photovoltaic (PV) panels and wind turbines (WTs), the tilt angle of PV panels, the height of WTs, the maximum fuel consumption, and the capacity of battery and heat storage tanks (HSTs). The multi-objective model is solved by a multi-obj... [more]

The Middle East is one among the areas of the world that receive high amounts of direct solar radiation. As such, the region holds a promising potential to leverage clean energy. Owing to rapid urbanization, energy demands in the region are on the rise. Along with the global push to curb undesirable outcomes such as air pollution, emissions of greenhouse gases, and climate change, an urgent need has arisen to explore and exploit the abundant renewable energy sources. This paper presents the design, performance analysis and optimization of a 100 MWe parabolic trough collector Solar Power Plant with thermal energy storage intended for use in the Middle Eastern regions. Two representative sites in the Middle East which offer an annual average direct normal irradiance (DNI) of more than 5.5 kWh/m²/day has been chosen for the analysis. The thermodynamic aspect and annual performance of the proposed plant design is also analyzed using the System Advisor Model (SAM) version 2017.9.5. Based on... [more]

The main goal of the research was to optimize microwave-assisted simultaneous distillation and extraction (MA-SDE) using response surface methodology (RSM), based on Box−Behnken design (BBD). A process was designed to extract the essential oil from the leaf sheath of Siam cardamom. The experimental data were fitted to quadratic equations, and the experiment conditions for optimal extraction of 1,8-cineole were extraction time 87.68 min, material-to-water ratio 1:13.18 g/mL and microwave power 217.77 W. Under such conditions, the content of 1,8-cineole was 157.23 ± 4.23 µg/g, which matched with the predicted value. GC−MS results indicated the presence of predominant oxygenated monoterpenes including 1,8-cineole (20.63%), iso-carveol (14.30%), cis-p-mentha-1(7),8-dien-2-ol (12.27%) and trans-p-2,8-menthadien-1-ol (9.66%), and oxygenated contents were slightly higher in the MA-SDE and extraction compared to usual SDE. In addition, the essential oil extracted by MA-SDE exhibited strong ant... [more]

Oil pollutants, due to their toxicity, mutagenicity, and carcinogenicity, are considered a serious threat to human health and the environment. Petroleum hydrocarbons compounds, for instance, benzene, toluene, ethylbenzene, xylene, are among the natural compounds of crude oil and petrol and are often found in surface and underground water as a result of industrial activities, especially the handling of petrochemicals, reservoir leakage or inappropriate waste disposal processes. Methods based on the conventional wastewater treatment processes are not able to effectively eliminate oil compounds, and the high concentrations of these pollutants, as well as active sludge, may affect the activities and normal efficiency of the refinery. The methods of removal should not involve the production of harmful secondary pollutants in addition to wastewater at the level allowed for discharge into the environment. The output of sewage filtration by coagulation and dissolved air flotation (DAF) floccul... [more]

Struvite crystallization using fluidized bed reactors (FBRs) is one of the most commonly used methods for nutrient recovery from different waste streams. However, struvite recovery from swine wastewater containing much higher solids using FBR has not been studied extensively. In this study, we therefore designed and optimized the key operating conditions parameters, i.e., pH (9.0, 9.5, and 10.0), circulation rate (CR) (1.5, 3.0, and 4.5 L/Lreactor·h), and hydraulic retention time (HRT) (1, 3, and 5 h) of FBR to ensure efficient nutrient removal and struvite crystallization from swine wastewater using response surface methodology (RSM) with central composite design (CCD) as experimental design. A magnesium/phosphorus (Mg/P) molar ratio of 1.3 was maintained with MgCl2 according to ortho-phosphate (O-P) concentration of influent and an air diffuser was set to supply air with 0.03 L air/Lreactor·min. The O-P recovery efficiency of over 91% was achieved through the entire runs. Among the o... [more]

The use of forward osmosis (FO) for water purification purposes has gained extensive attention in recent years. In this review, we first discuss the advantages, challenges and various applications of FO, as well as the challenges in selecting the proper draw solution for FO, after which we focus on transport limitations in FO processes. Despite recent advances in membrane development for FO, there is still room for improvement of its selective layer and support. For many applications spiral wound membrane will not suffice. Furthermore, a defect-free selective layer is a prerequisite for FO membranes to ensure low solute passage, while a support with low internal concentration polarization is necessary for a high water flux. Due to challenges affiliated to interfacial polymerization (IP) on non-planar geometries, we discuss alternative approaches to IP to form the selective layer. We also explain that, when provided with a defect-free selective layer with good rejection, the membrane su... [more]

Thermochemical conversion of solid wastes through gasification offers the
dual benefit of production of high-value fuels and environmentally friendly
waste disposal. In this paper, we propose a novel process for production of
liquified synthetic natural gas (SNG) from waste tires via a rotary kiln gasification process. We use a combination of experimental data available in the
open literature, first principles mathematical models and empirical models to
study three design cases (without CCS, with precombustion CCS and with
pre- and postcombustion CCS) in two locations (USA and Norway). The
thermodynamic, economic and environmental performance of the concept is
studied. The results show that minimum selling prices of 16.7, 17.5 and 19.9
$/GJ_LHV,SNG are required for USA and 20.9, 21.8 and 24.9 $/GJ_LHV,SNG
for Norway. We note that these prices may become competitive under certain
regulatory conditions (such as recent public policy movement in British
Columbia, Canada requiri... [more]

Arbutus unedo L., commonly known as the strawberry-tree fruit, is an endemic species of the Mediterranean flora. Microwave extraction technology has been considered as a fast and “green” method for the production of extracts rich in bioactive compounds, although the energy consumption is high. To overcome this bottleneck, microwave was used as a pretreatment procedure in short time periods. This technique promotes the burst of intracellular vacuoles leading to an increase in the lixiviation of phenolic compounds. Different approaches were tested, namely a solvent-free irradiation (SFI), a solvent-assisted irradiation (SAI) and a pressurized solvent-assisted irradiation (PSAI). After irradiation, a solid−liquid extraction procedure was performed using a mixture of water and ethanol. A kinetic evaluation of the total phenolic content (TPC) was performed using the Folin−Ciocalteu method. For the total anthocyanin content, a UV-spectrophotometric method was used. HPLC-UV and LC-MS were use... [more]

The aim of this study is to indicate the influence of pretreatment, consisting of grinding vegetables and then freezing and thawing the raw material before pressing on the process efficiency and quality of obtained juice. The subject of the research was celeriac root (Apium graveolens L) of the Edward variety. Juice pressing was carried out in a laboratory basket press. The pressing yield and specific energy were values characterizing the pressing process, while pH and the extracted content in the juice were used to assess the juice quality. The experiment was performed according to three procedures. In each of them, the ground celeriac root (pulp or chips) was initially pretreated through freezing and thawing and then pressed twice. Among the examined methods of obtaining juice, the most beneficial method was pressing juice from the pulp, then freezing and thawing the pomace obtained in the first cycle, and finally, pressing the pomace. It is an energy-optimal method and guarantees a... [more]

Supercritical fluid extraction comprises a known technology applied to obtain volatile compounds from flowers, i [...]

Solar energy is considered one of the most important renewable energy resources, and can be used to power a stand-alone photovoltaic (SAPV) system for supplying electricity in a remote area. However, inconstancy and unpredictable amounts of solar radiation are considered major obstacles in designing SAPV systems. Therefore, an accurate sizing method is necessary to apply in order to find an optimal configuration and fulfil the required load demand. In this study, a novel hybrid sizing approach was developed on the basis of techno-economic objectives to optimally size the SAPV system. The proposed hybrid method consisted of an intuitive method to estimate initial numbers of PV modules and storage battery, an iterative approach to accurately generate a set of wide ranges of optimal configurations, and a Pareto envelope-based selection algorithm (PESA-II) to reduce large configuration by efficacy obtaining a set of Pareto front (PF) solutions. Subsequently, the optimal configurations were... [more]

The combined cooling, heating and power (CCHP) system not only has high energy efficiency but also has different load structures. Traditional separate production (SP) system and power supply system do not consider the land cost in terms of the environmental benefits, and in the aspect of the power supply reliability, the grid-connected inverter cost is also ignored. Considering the deficiency of the traditional energy supply system, this paper builds the CCHP system construction cost model. The particle swarm optimization (PSO) is adopted to find out the minimum value of the construction cost, and the optimal system construction scheme is constructed from three aspects which are system reliability, economic benefits and environmental benefits. In this paper, the typical daily data, as well as the meteorological data and the load data, in the last four years are taken as experimental dataset. The experimental results show that compared with the traditional SP system and power supply sys... [more]

The article presents some of the research on the wider work related to testing and improving a new rotary cleaning device. The new cereal grain cleaning and separation device can support the development of sustainable agriculture in terms of seed purity and quality. This device is especially useful for small and medium-sized farms. This device has the characteristics of a multi-stage screen aided by an air stream (i.e., by pneumoseparation). The prototype was constructed at the University of Life Sciences in Lublin. The research was conducted at a test stand, which allowed changes in the operating parameters of the cleaner and their measurement. The scope of the tests included determining the influence of the inclination angle of the sieve unit (α) on the effectiveness and efficiency of oat grain cleaning. The experiment was carried out using two rotational spindle speeds: 5 and 75 rpm. The quality of the separation and cleaning of oat grains was evaluated using six cleaning process pa... [more]