Energy Recovery Ratio Research Articles

An innovative hybridization of electrodialysis with reverse osmosis for brackish water desalination

It is reported in the literature that Electrodialysis Desalination (ED) is the most efficient for groundwater (<7 ppt), while Reverse Osmosis (RO) is for higher salinity (8–50 ppt). Thus, the present paper proposes a novel arrangement of ED-RO for brackish water desalination. ED is used first for brackish water desalination, while RO treats the highly concentrated outlet of the ED part. Energy consumption, water production, recovery ratio, and water cost are the performance indices discussed in this paper. These are presented against the influential input parameters, which are selected based on a sensitivity analysis. The results show that the new system is economically feasible for inlet salinity of 2.5–7.8 ppt. Standalone RO could be better for salinity more than eight (8) ppt, and standalone ED is better for a source salinity of less than two (2) ppt. Energy consumption results emphasize that the ED-RO integration is the most energy-effective for the feed salinity of < 9.5 ppt. The net recovery ratio for the hybrid ED-RO plant is 87.5% when ED and RO plants operate at a recovery ratio of 75% and 50%, respectively. For typical conditions and brackish water salinity of 5 ppt, ED-RO shows an outstanding performance of 0.731 kWh/m3 for energy consumption and 0.370 $/m3 for water cost. These values are better than those of standalone RO and ED plants.

Thermal-chemical conversion of sewage sludge based on waste heat cascade recovery of copper slag: Mass and energy analysis

Thermo-chemical conversion method can transform sewage sludge (abbreviated as SS) to bio-char with hydrogen-rich gas and has good prospects for development. In this research, copper slag was used as heat carrier and provide energy for conversion process of SS. A method of carbonization-activation waste heat cascade recovery technology system was designed. In this technology process, multi-stage endothermic chemical reactions absorb sensible heat from hot copper slag particles. Syngas, activated carbon (abbreviated as AC) and char are produced from SS. Mass and energy balance of this system were evaluated. The results showed that waste heat recovery efficiency and byproducts' additional value were improved by this method comparing with traditional water quenched method. Increasing heat quantity of carbonization process can improve system's energy recovery ratio. In theory, under the optimal condition (T2 = 700 °C, T3 = 200 °C), waste heat recovery ratio and exergy recovery ratio reach 90.8% and 94.9%, respectively.

Cavitation erosion behavior of nitinol coating sealed by epoxy resin

AbstractThe nitinol coating against cavitation erosion was prepared by air plasma spraying and sealed with epoxy resin successfully. After the coating sealed with epoxy resin, the pores and cracks of the coating were filled with the epoxy resin and then the cohesiveness between the lamellae was improved, the hardness increased from 3.68 GPa to 7.49 GPa, the energy recovery ratio (superelasticity) was improved from 41.9 % to 49.0 % and the toughness was enhanced from 0.011 GPa to 0.045 GPa. During the cavitation erosion test, the epoxy resin reduced the cavitation resources and absorbed the impact energy from the micro‐jet or shock waves. Meanwhile, the high hardness and superelasticity can help the coating to resist cavitation erosion and the high toughness can delay the expansion of cracks during the cavitation erosion test. As a result, after cavitation erosion for 300 min the cumulative mass loss of the coating sealed by epoxy resin was 1/5 times as much as that of the nitinol coating without sealing. Therefore, the cavitation erosion resistance of the nitinol coating can be improved by sealed with epoxy resin.

Investigation of Paraffin Wax with ZnO Nanorods for Performance Enhancement of Solar Thermal Energy Storage. (Dept.M)

This paper discusses the influence of paraffin wax inoculated with ZnO-nanorods on the latent heat of thermal energy storage (LHTES) of solar water heating system. The main objective of the experimental study is to determine the percentage increase in thermal storage capacity of using paraffin wax with 0.15 wt.% ZnO-nanorods as nano-composite phase change material (NCPCM) to the raw paraffin wax as base phase change material (PCM). The experiments were performed by 33-liter insulated stainless-steel storage shell TES tank containing 21 copper tubes 5/8-inch in diameter. The TES tank is filled with circulating water and the tubes are filled with either the pure PCM or NCPCM. The water is the heat transfer fluid (HTF) in the TES tank. The experiments were done at different HTF flow rates to study the best flow rate that increases both the amount of heat transfer and melting rate of PCM. It was found that 0.15 wt.% ZnO NCPCM decreases the charging and discharging time compared to the pure PCM, and a percentage increase is achieved in thermal energy storage by 20% when using 0.15 wt.% ZnO nanorods. The results also reveal that the maximum discharge energy was raised from 266 kW for pure paraffin wax to 306 kJ for 0.15 wt.% ZnO NCPCM. The NCPCM at 6 l/min HTF flow rate provides the highest energy recovery ratio (ERR), while the smallest occurs at 9 l/min.

Effect of thermochemically fractionation before hydrothermal liquefaction of herbaceous biomass on biocrude characteristics

Abstract Hydrothermal liquefaction (HTL) of fractionated two types herbaceous biomass (kenaf and miscanthus) by dilute acid, organosolv, alkaline, or demineralization process was carried out under ethanol water co-solvent at 350 °C for 30 min to examine the biocrude yield and characteristics. The biocrude properties were comprehensively characterized by HPLC, elemental, GC-MS, and TGA analysis. Fractionation technologies before HTL effectively increased biocrude yield up to 38% compared to that of untreated herbaceous biomass (31%), except for organosolv fractionation of miscanthus, especially, HTL after alkaline fractionation showed high yield and energy recovery ratio up to 70%. Elemental analysis showed that HHV of biocrude was negatively affected by hydrolysis reaction of high lignin content after dilute acid fractionation. The GC-MS analysis revealed that carbohydrates-derived compound significantly increased in the biocrude obtained after organosolv and alkaline fractionation due to holocellulose increases through fractionation process. Additionally, TGA results indicated that the ratio of high-boiling-point compounds in biocrude obtained after demineralization was expanded compared with untreated due to ash removal, which could act as a catalyst.

Green and efficient two-step degradation approach for converting Powder River Basin coal into fuels/chemicals and insights into their chemical compositions

A green and efficient two-step degradation approach, including supercritical CO2/ethanol degradation and oxidation in aqueous hydrogen peroxide solution, was reported to convert Powder River Basin coal into fuels/chemicals. In total, 43.5 wt% liquid tar and 23.3 wt% oxidation products were obtained from the two-step degradation. The liquid tar was facilely separated into light oil and asphaltene, with yields of 27.3 wt% and 16.5 wt%, respectively. The first-step degradation has high energy recovery (50%) and low energy consumption ratio (minimum 0.17), indicating an energetic net energy gain. The light oil is a promising feedstock as clean liquid fuels due to its high H/C ratio (1.58) and heating value (34.56 MJ/kg). The asphaltene with lower H/C and O/C ratios but higher aromaticity (0.83) could be a good precursor for carbon materials. The light oil can be upgraded into clean liquid fuels by hydrodeoxygenation or used as feedstock for producing oxygenated chemicals because it is rich in oxygenated components. Phenols and aliphatic esters account for 74.2% of the volatile components in the light oil. High resolution mass spectrometric analysis revealed that the O1–O4 class species are dominant components with relative abundance of 71% in the light oil. Valuable carboxylic acids with total yields of 19.7 wt%, especially alkanedioic and alkanetricarboxylic acids, were produced from oxidation of the scCO2/ethanol degradation residue, which is a promising second-step degradation to utilize the residue. This study provides an efficient coal conversion processes for producing fuels/chemicals and reducing energy consumption and environmental impact.

Proposal and analysis of a coupled power generation system for natural gas pressure reduction stations

With the increased use of natural gas, it is valuable to study energy recovery ratio in the natural gas pressure reduction stations (PRSs). This paper focused on recovering the energy in PRSs as well as low-grade waste heat by a coupled power generation system (CPGS). The CPGS integrates a natural gas expansion (NGE) subsystem and an organic Rankine cycle (ORC) subsystem driven by low-temperature waste heat. Firstly, a comparative analysis is carried out between the separated natural gas expansion system and the separated ORC system. Then, the effects of heat source conditions, upstream pressure of natural gas and the isentropic efficiency of the natural gas expander are investigated. At last, working fluids selection is conducted with respect to two different pressure ranges of natural gas. The results show that there is an optimal temperature and mass flow rate of the heat source that maximizes the system exergy efficiency. With the increase of the upstream pressure of natural gas, the net power output and waste heat recovery factor increase while the system exergy efficiency has an optimal point. Furthermore, the isentropic efficiency of the natural gas expander has a great influence on the net power output of the system.

Effect of moisture conditioning on mechanical and healing properties of inductive asphalt concrete

The objective of this paper was to study the effect of hydrodynamic impact on durability and healing performance of inductive asphalt concrete (IAC) through moisture induced sensitivity test (MIST). AC-13 inductive asphalt concrete containing steel fiber was designed and Marshall specimens were prepared to suffer MIST in orthogonal condition. After MIST, cutting was performed to observe the corrosion of steel fibers inside while semi-circular bending (SCB) test was conducted to evaluate the mechanical properties. Then fracture-healing procedure was carried out to investigate the strength recovery ratios of the specimens before and after MIST. Meanwhile, the crack healing ratio and change of air voids inside asphalt concrete were observed by computed tomography (CT) scan test. The results showed that there was no corrosion of steel fibers inside samples after short term simulation in the laboratory. The tensile strength and fracture energy decreased after MIST. The changing trends of strength recovery ratio and fracture energy recovery ratio were consistent with that of tensile strength. CT-scan indicated that the healing ratio of crack was up to 92.3%. The initial air void content of asphalt concrete was 4.7%, 5.7% after adding steel fibers, and 4.87% after induction heating. However, the air void changed from 5.7% to 6.8% after MIST. Orthogonal test factor analysis showed that temperature was the most significant factor affecting the durability of asphalt concrete during MIST.

Heat pump operated humidification-dehumidification desalination system with option of energy recovery

ABSTRACT This study investigates the performance of a novel humidification dehumidification (HDH) desalination system integrated into a vapor compression (VC) heat pump. The integrated heat pump delivers the necessary heating and cooling loads to the HDH desalination unit. Three different layouts (system A, system B, and system C) of water desalination plants are proposed and evaluated analytically at different operating conditions, such as water temperature, water flowrate, mass flowrate ratio (MR), and humidifier effectiveness. The investigated performance metrics of the proposed HDH desalination system are the gained output ratio (GOR), freshwater production rate, specific electrical energy consumption (SEEC), recovery ratio (RR) and cost of freshwater production. System A is without heat recovery, system B has heat recovery through preheating feed inlet saline water, while system C has heat recovery through preheating inlet air to the humidifier. The parametric analysis indicates that GOR, water productivity, and RR improve with increasing water temperature and humidifier effectiveness, while the specific electrical energy consumption decreases at the same conditions. The findings show the existence of an optimum mass flowrate ratio (MR) at which system performances are maximized. Results also reveal that the systems with the option of energy recovery provide the highest gained output ratio, recovery ratio and productivity, and the least specific electrical energy consumption. Additionally, depending on various system and cost parameters, the price of freshwater production from the proposed systems varies from 34.27 $/m3 to as low as 7.33 $/m3 of freshwater.

Study on recovery of biogas from mixed biowaste for regional biogasification system

Even in Japan, the energy recovery from a waste became the importance by not only wastetreatment problem but also environmental problem which carbon dioxide (CO2) causes. Theenergy recovery is being measured from organic waste. However, the construction of thedisposing facility does not advance in actually various factors. As the one factor, the property ofa organic waste variously changes by the discharge source such as home, food shop, supermarket, farm, sewage treatment plant, etc., and the energy recovery ratio changes with it. In thisstudy, the biogas generation of the waste which arose actually was obtained experimentally. Inaddition, the following were examined using waste generation in the region and the biogas frombiowaste : Electric power recovery, heat recovery, CO2 emission. In the garbage discharged, thegas generation magnification showed the very high, The gas yields seemed to be very high forbiowastes, since these is originally offered as foods. In case of the livestock manure, the gasyield over about 16 times per manure was obtained. The gas yield is not very dependent on theorganic substance content. This cause the bedding was included in the manure, and it seemed toaffect the organic substance content by the content and type. In case of the sewage sludge, thegas yield of about 3.5 times per sludge was got. As a result of the trial based on the wastegeneration in the region, electric power, heat can be utilized effectively. In addition, that thereduction was also possible on CO2 emission clarified.

Integrating a supercapacitor with capacitive deionization for direct energy recovery from the desalination of brackish water

The importance of energy recovered from desalination techniques has been of considerable interest because of increasing water scarcity and energy crises. Capacitive deionization (CDI), a promising desalination technology using pairs of carbon electrodes under an electric field, has an attractive advantage in that energy stored during the charging step for salt removal can be further recovered during the discharging step. In this research, an energy recovery system based on a four-switch buck-boost converter with variable frequency was successfully constructed to transfer electric energy from a CDI module to a supercapacitor. The effects of the influent NaCl concentration and the distance between two oppositely placed electrodes were investigated on both the desalination behavior and energy recovery performance. The experimental procedure involved a charging step for ion removal, stop-flow operation for energy recovery, and discharging step for electrode regeneration. For the desalination of a 10 mM NaCl solution, a deionization capacity of 10.1 mg g−1 and a total energy input of 0.09 kWh m−3 were obtained. Overall, as demonstrated, a higher energy recovery ratio was achieved with a higher influent NaCl concentration and a shorter distance between the two electrodes. Significantly, up to 49.6% of the energy stored in the CDI module while reducing the salinity of a 50 mM NaCl solution could be directly recovered, indicating that the energy recovery system based on a four-switch buck-boost converter shows superior performance. The utilization of CDI integrated with a supercapacitor in this work holds great potential in both low-energy-requirement desalination and high-efficiency energy storage.

Potential energy regeneration method and its engineering applications in large-scale excavators

Hydraulic excavators are essential excavation machines, with more than 3.8 million sets in use in the mining, and engineering and architectural engineering construction fields. However, during the working process, a large amount of gravitational potential energy is wasted, causing low energy efficiency and poor emissions. Taking a large-scale excavator as an example, during a certain 90° excavation process, the gravitational potential energy wastage of the working device is approximately 975.1 kJ, which amounts to at least 20% of the energy consumption of the entire machine, causing significant energy waste and serious pollution. And, during the boom lowering process, the changing rate of potential energy is about 406.4 kW. In order to improve the energy efficiency of hydraulic excavators, the recovery of this huge energy that changes rapidly with low cost and high efficiency is a big problem that must be solved. This paper proposes a gravitational potential energy recovery scheme with an energy conversion cylinder and a hydraulic accumulator. Using this scheme, the gravitational potential energy of the working device can be stored and reused directly, without increasing the cost and install power of the machine largely. In the study, first, the system parameters are designed, following which the multidisciplinary dynamic model of the hydraulic excavator is established. The influence of the accumulator parameters on the energy recovery ratio is studied based on the model. The results demonstrate that with the newly designed system more than 75.9% of the gravitational potential energy can be stored in the accumulator during the lowering process. Moreover, during a certain lifting process, the input energy to the pump can be reduced by 52%. On this basis, a 76 t hydraulic excavator test system is constructed using the above principle. The experimental results match strongly with the co-simulation results. The energy consumption can be reduced to approximately 238 kJ during a certain 90° excavation cycle, and the system can reduce the carbon dioxide emissions by 28088.4 kg per year. The energy-saving and emission-reduction effects are remarkable; furthermore, this principle can directly be applied to other lifting machines.

Energy recovery from the flow-electrode capacitive deionization

The energy consumed during the desalination process in a flow-electrode capacitive deionization (FCDI) is recovered by a two-chamber device, where the adsorbed electrodes are discharged with constant current. When single constant discharge current is applied, the maximum energy of 36.3 J can be obtained with 0.50 mA/cm2 discharge current density. Much more energy is recovered by applying successive discharge currents. With additional conductive agent carbon nanotubes in the suspend carbon electrodes, the ratio was further enhanced by 60%. Increased salt concentration of the electrolyte could decrease the energy consumption and improve the energy recovery. The energy recovery ratio was promoted to 9.4% when the salt concentration of the electrolyte increased to 9.60 g L−1.

Design and Simulation of a Multimodule Superconducting Inductive Pulsed-Power Supply Model for a Railgun System

The superconducting inductive pulsed-power supply (IPPS) is considered to have broad application prospects in the field of electromagnetic launch because of its low electrical loss. In order to obtain a higher efficiency in continuous electromagnetic launch, a repetitive IPPS circuit topology based on a high-temperature superconducting pulse power transformer (HTSPPT) has been proposed in our previous studies. It can recover most of the remaining energy for generating continuous current pulses by using a bridge-type capacitive switching circuit. As a follow-up work, this paper presents a multimodule repetitive superconducting IPPS model for a railgun system. This multimodule model consists of 24 HTSPPT modules connected to an XRAM-like circuit topology. In order to verify the feasibility of the repetitive superconducting IPPS and study its driving characteristics, the dynamic launching process of a simple 4-m-long railgun system was simulated. The influence of the capacitance in the bridge-type capacitive switching circuit on the main performance of the system, such as the maximum output current, the maximum primary voltage, the launch efficiency, the maximum capacitive energy ratio, and the remaining energy recovery ratio, was analyzed. The simulation results show that the repetitive superconducting IPPS is suitable for driving the simple railgun. In addition, it also concluded that the system performances conflict with each other and the optimal capacitance value for each HTSPPT module should be determined by the tradeoff of system performances.

Thermo-kinetics and gaseous product analysis of banana peel pyrolysis for its bioenergy potential

This study illustrated the pyrolysis of banana peel (BP) as a potential waste management solution. Samples were characterized through Fourier transform infrared spectrometry (FTIR), elemental analysis, and high heating value (HHV) calculation. After pyrolysis experiments were performed at different heating rates (10, 20, 30, and 40 °C min−1) by using a thermogravimetric analyzer coupled with FTIR (TG-FTIR), the apparent activation energies were computed with Friedman, Kissinger–Akahira–Sunose (KAS), and Flynn–Wall–Ozawa (FWO) methods, and the evolved gaseous products were analyzed simultaneously. During pyrolysis, BP underwent three devolatilization steps accompanied by the evolution of some major gaseous products, including CO2, CH4, H2O, CH3COOH, CC, C6H5OH, HCOOH, and CH3CH2OH. Among them, CC, CH3COOH, and CO2 accounted for approximately 71.56% of the total gaseous products. Gas evolution was more significantly influenced by the pyrolysis temperature than by the heating rate. Pyrolysis–gas chromatography/mass spectrometry (Py-GC/MS) analysis confirmed the presence of some high-energy compounds and valuable chemicals containing aromatic, aldehyde, ketone, and other functional groups. In terms of preliminary energy balance, more than 70% of the total energy output was attributed to the liquid pyrolytic products followed by the solid and gaseous products. The energy recovery ratio of BP pyrolysis was superior to that of other fuel feedstocks. This work provided insights into resolving environmental problems associated with BP management by pyrolyzing BP as a potential source of renewable bioenergy.

Thermal efficiency extends distance and variety for honeybee foragers: analysis of the energetics of nectar collection and desiccation by Apis mellifera.

The desiccation of nectar to produce honey by honeybees ( Apis mellifera L.) is an energy-intensive process, as it involves a quasi-isothermal change in the concentration of sugars from typically 20 to 80% by vaporization (honey ripening). This analysis creates mathematical models for: the collected nectar to honey ratio; energy recovery ratio; honey energy margin; and the break-even distance, which includes the factors of nectar concentration and the distance to the nectar from the nest; energetics of desiccation and a new factor, thermal energy efficiency (TEE) of nectar desiccation. These models show a significant proportion of delivered energy in the nectar must be used in desiccation, and that there is a strong connection between TEE and nest lumped thermal conductance with colony behaviour. They show the connection between TEE and honeybee colony success, or failure, in the rate of return, in terms of distance or quality of foraging. Consequently, TEE is a key parameter in honeybee populations and foraging modelling. For bee keeping, it quantifies the summer benefits of a key hive design parameter, hive thermal conductance and gives a sound theoretical basis for improving honey yields, as seen in expanded polystyrene hives.

Study on Energy Analysis of Drilling Rig and Energy Storage Supercapacitor Configuration

It is an effective approach for recycling the energy during the process of lowering drill string and casing to reduce the cost of the oil drilling rig lifting system. In the present work, for the multi-model drilling rig, the total energy recovery and energy-saving ratio are calculated with considering the effect of hook without loading. The total energy recovery and energy-saving ratio is significantly increased when hook without loading is considered. Employing the supercapacitor, an automatic energy storage system is designed, and the control strategy of this system is discussed. The energy of lowering drill string and hook without loading is recycled for the energy replenish of lifting drill string and hook without loading. The selection and analysis of the supercapacitor in the system configuration must take into consideration the quantity, volume, quality, and the utilization of the supercapacitor at the same time, selecting the suitable capacity of the supercapacitor for reducing the cost of drilling effectively.

Renewable diesel blendstocks produced by hydrothermal liquefaction of wet biowaste

Processing wet biowaste to create a useful product, a practice called valorization, is environmentally sustainable and has the potential to augment energy production. Biocrude converted from wet biowaste using hydrothermal liquefaction (HTL) has comparable heating values to petroleum crude. However, its composition is too complex for use as transportation fuels. Here, we show that distillation combined with esterification can effectively upgrade HTL biocrude oil into diesel blendstock. We demonstrate that the HTL biocrude oil converted from food processing waste and animal manure can be distilled into fractions with similar energy content to that of petroleum diesel. We then reduce the acidity of distillates through esterification to meet the diesel standard. Engine tests performed using 10–20% upgraded distillates blended with diesel show 96–100% power output, 101–102% NOx, 89–91% CO, 92–125% unburned hydrocarbon and 109–115% soot emissions, compared with regular diesel. HTL integrated with distillation and esterification has a higher energy recovery ratio than anaerobic digestion, lipid extraction, HTL combined with hydrotreating and producing diesel from petroleum. This approach realizes the potential of wet biowaste to alleviate petroleum consumption and to reduce greenhouse gas emissions. Wet biowaste from food processing and animal manure can be converted into biocrude oil using HTL. In this study, the authors combined distillation and esterification to upgrade biocrude into diesel blendstock and performed engine tests using it.

Performance analysis of a heat pump driven humidification-dehumidification desalination system

In this paper, a humidification-dehumidification desalination HDH cycle with direct contact dehumidifier is coupled with a heat pump. The heat pump is introduced in order to simultaneously supply the cooling and heating loads of the HDH cycle. Next, by implementing a mathematical model, the performance of the system is investigated under different working conditions. To incorporate the humidifier and dehumidifier effectiveness into the theoretical modeling, the ε-NTU correlation of the heat and mass transfer device is utilized. Performance parameters such as specific electrical energy consumption (SEEC), recovery ratio (RR) and coefficient of performance (COP) are employed for evaluating the system performance. The fully coupled condition of the HDH system with no extra cooling or heating scenarios is investigated. It is shown that a given saline water and freshwater temperatures, a fully coupled HDH system with the heat pump without adding the extra cooler can be achieved by alternating mass flow rate ratio of either seawater to freshwater or seawater to dry air.

Transformational and pseudoelastic characteristics of melt-spun Ti50Ni25Cu25 shape memory ribbon crystallized and aged at a low temperature

The aim of this study is to understand the properties of amorphous Ti50Ni25Cu25 shape memory ribbon crystallized and aged at a temperature lower than its crystallization temperature. The hardness and pseudoelasticity (PE) performance of the ribbons aged at 435 °C, for different intervals, are characterized by nanoindentation. The 435 °C-aged ribbon is fully crystallized and exhibits the lowest hardness value of 5.3 GPa when the aging time reaches 300 min. With increasing aging time to 600 min, the hardness of the ribbon rises to 7.9 GPa due to the strong precipitation hardening effect caused by the fine and dense TiCu precipitates. Additionally, both depth recovery ratio (DRR) and energy recovery ratio (ERR) associated with the PE performance are effectively promoted by this precipitation hardening effect. Under the applied force of 20 mN (equals to the average contact pressure of 4.6 GPa) the DRR and ERR are 86.0% and 85.7%, respectively, which are higher than those of Ti50Ni25Cu25 ribbons crystallized and aged at 500 °C. Experimental results indicate that aging at a temperature lower than the crystallization temperature can effectively improve the mechanical and functional properties of amorphous Ti50Ni25Cu25 shape memory ribbon.