High Energy Recovery Research Articles

PV cell-driven humidification-dehumidification (H/D) process for brine treatment

This study was to technically evaluate a solar still desalination system driven by photovoltaic (PV) cells for treatment of a brine wastewater through evaporation (humidification) and subsequent condensation (dehumidification) processes. Based on the solar radiation data in Shanghai, China, solar energy utilization, freshwater production, and salt production were estimated. Results showed that under the identical operating conditions, air forced convection (5.9 m·s–1) exhibited a better performance than free convection with the regards toward air humidification and freshwater productions. However, free convection had much higher energy recovery. Our study demonstrated that the new solar still, powered directly and indirectly by solar energy, is an effective and economic desalination process, and it may be very useful in rural communities.

A high luminosity ERL on ring e^-e^+ collider for a super charm factory

A high luminosity energy recovery linac-on-ring type electron-positron collider operating as super charm factory is proposed. It is shown that a luminosity above L = 10^{35}cm^{-2}s^{-1} can be achieved for center of mass energy \sqrt{s}=3.77 GeV. The physics goals of this machine in investigation for charmed particles properties are briefly discussed.

GA-based neural network for energy recovery system of the electric motorcycle

This paper discusses a regenerative braking system for the electric motorcycle that performs regenerative energy recovery based on neural network control with a boost converter. A constant regenerative current control scheme is proposed, thereby providing improved performance and high energy recovery efficiency at minimum cost. The neural network controller is used to simulate the regenerative system in Matlab/Simulink and neural network toolbox. We can sieve out the suitable training samples to obtain good performance of the controllers, and the neural network with genetic algorithms is used to design the controller. Simulation results of neural network controller show a more steady quality and extended time of charging. The proposed scheme not only increases the traveling distance of the vehicle but also improves the performance and life-cycle of batteries, and the energy recovery of batteries becomes more stable. Therefore, the market of the electric vehicle will become more competitively.

Rice mill wastewater treatment in microbial fuel cells fabricated using proton exchange membrane and earthen pot at different pH

Performance of microbial fuel cells (MFCs), fabricated using an earthen pot (MFC-1) and a proton exchange membrane (MFC-2), was evaluated while treating rice mill wastewater at feed pH of 8.0, 7.0 and 6.0. A third MFC (MFC-3), fabricated using a proton exchange membrane (PEM), was operated as control without pH adjustment of the acidic raw wastewater. Maximum chemical oxygen demand (COD) removal efficiencies of 96.5% and 92.6% were obtained in MFC-1 and MFC-2, respectively, at feed pH of 8.0. MFC-3 showed maximum COD removal of 87%. The lignin removal was 84%, 79%, and 77% and the phenol removal was 81%, 77%, and 76% in MFC-1, MFC-2, and MFC-3, respectively. Maximum sustainable volumetric power was obtained at feed pH of 8.0, and it was 2.3 W/m 3 and 0.53 W/m 3, with 100 Ω external resistance, in MFC-1 and MFC-2, respectively. The power was lower at lower feed pH. MFC-3 generated lowest volumetric power (0.27 W/m 3) as compared to MFC-1 and MFC-2. More effective treatment of rice mill wastewater and higher energy recovery was demonstrated by earthen pot MFC as compared to MFC incorporated with PEM.

Chemical Repair of Plasma Damaged Porous Ultra Low-k SiOCH Film using a Vapor Phase Process

A vapor phase based silylation process was used to restore plasma damaged porous ultra low-κ SiOCH dielectric films. The process was carried out with eleven different silylation agents. After processing of blanked wafers, the restoration performance was characterized by different analytic techniques like Fourier Infrared and Auger electron spectroscopy as well as contact angle and mercury probe measurements. Quantum mechanics calculations and practical results suggest three repair chemicals having two reactive groups to be most promising. However, a comparable electrical improvement, i.e. κ-value improvement was achieved with chemicals having one reactive group. A thin dielectric layer formation was found to be one explanation for this effect. This is supported by a high surface free energy recovery after the repair process, without carbon incorporation near the surface. Hence, depending on the requirement to the restoration (κ-value, carbon restoration, etc.) chemicals having one reactive group can be sufficient as well.

Can stunned hearts be resuscitated? Evaluation of aspartate/glutamate secondary blood cardioplegia using magnetic resonance spectroscopy.

Objectives: Reperfusion of ischemic hearts with warm, substrate-enriched, blood cardioplegia may alleviate post-ischemic metabolic and functional derangements. This study investigates this possibility using (31)P magnetic resonance (MR) spectroscopy. Methods: Fifteen blood-perfused Langendorff pig hearts were subjected to 30 min of total, normothermic ischemia. Control hearts (n=8) were reperfused with blood for 40 min. Experimental hearts (n=7) received 20 min of aspartate/glutamate (asp/glu) enriched blood cardioplegic solution, followed by 20 min of normal blood. (31)P MR spectroscopy was used to observe cellular energetics and intracellular pH (pHi) throughout the experiments. Left-ventricular function and myocardial oxygen consumption were evaluated before and after ischemia. Results: MR spectra showed no improvement in the rate or extent of high-energy phosphate recovery with asp/glu cardioplegia, but showed a transient increase in pHi during cardioplegic reperfusion (p<0.05). This, however, did not affect post-ischemic recovery of high energy metabolites, myocardial function or oxygen consumption. Conclusions: This study raises questions regarding the potential beneficial effects of asp/glu enriched secondary cardioplegic solution on functional or metabolic status of stunned pig hearts. Extrapolation of these results to humans should be viewed with caution. Keywords: Magnetic resonance; Pig heart; Aspartate; Glutamate; Cardioplegia; Myocardial stunning.

Design of energy recovery system for electric motorcycles using fuzzy theory

This paper discusses a regenerative braking system for electric motorcycles that performs regenerative energy recovery based on fuzzy logic control with a boost converter. A constant regenerative current control scheme is proposed, thereby providing improved performance and high energy recovery efficiency at minimum cost. Experimental results of electric motorcycles show that the proposed regenerative braking control st ategy not only has excellent control performance, but also makes very significant energy saving possible.

P‐136: Low Cost and High Efficiency Energy Recovery Circuit for Driving AC Plasma Display Panel with Single Sustain Circuit Board

AbstractThis paper presents an energy recovery (ER) circuit which can improve the energy recovery efficiency and can drive AC PDP with a single sustain circuit board. The proposed ER circuit consists of one energy recovery inductor and two insulated‐gate bipolar transistors. To reduce power consumption in the parallel resonance mode of operation, the leading edge of the first sustain pulse and the trailing edge of the last sustain pulse are generated using a current build‐up operation. The measured energy recovery efficiencies of the proposed ER circuit were better than the conventional parallel resonance circuit. Experimental results on a 42‐inch XGA single scan PDP show that the proposed ER circuit is suitable for use in a PDP drive circuit.

Equilibrium ion distribution in the presence of clearing electrodes and its influence on electron dynamics

Here we compute the ion distribution produced by an electron beam when ion-clearing electrodes are installed. This ion density is established as an equilibrium between gas ionization and ion clearing. The transverse ion distributions are shown to strongly peak in the beam's center, producing very nonlinear forces on the electron beam. We will analyze perturbations to the beam properties by these nonlinear fields. To obtain reasonable simulation speeds, we develop fast algorithms that take advantage of adiabatic invariants and scaling properties of Maxwell's equations and the Lorentz force. Our results are very relevant for high current energy recovery linacs, where ions are produced relatively quickly, and where clearing gaps in the electron beam cannot easily be used for ion elimination. The examples in this paper therefore use parameters of the Cornell Energy Recovery Linac project. For simplicity we only consider the case of a circular electron beam of changing diameter. However, we parametrize this model to approximate nonround beams well. We find suitable places for clearing electrodes and compute the equilibrium ion density and its effect on electron-emittance growth and halo development. We find that it is not sufficient to place clearing electrodes only at the minimum of the electron beam potential where ions are accumulated.

Exergy analysis of the solar multi-effect humidification–dehumidification desalination process

An exergy analysis method is presented of the solar multi-effect humidification–dehumidification desalination (HDD) process. Pinch technology is used in the humidification process to determine the maximum possible saturated air temperature and the temperature of water rejected from the unit, and then the dehumidification process to determine the temperature of water leaving from the heat exchanger. The formulae to calculate the exergy of water and saturated air are given. The solar plane collector is used. From exergy analysis, the solar collector has the lowest exergy efficiency; the HDD process has a lower exergy efficiency, and the water rejected has also a large exergy loss. The energy and exergy recovery rate of the desalination process is also lower. The solar multi-effect HDD process has much room for improvement. Three ways to enhance fresh water output per square meter area of solar collector are suggested. The first is to enhance the energy and exergy efficiency, that is, to take measures for larger amounts of energy and exergy. The second is to improve the flow of the solar multi-effect HDD process in order to gain a high energy recovery rate and the gain output ratio. The last is to reuse the rejected water to obtain fresh water.

Salinity-gradient power: Evaluation of pressure-retarded osmosis and reverse electrodialysis

A huge potential to obtain clean energy exists from mixing water streams with different salt concentrations. Two membrane-based energy conversion techniques are evaluated: pressure-retarded osmosis and reverse electrodialysis. From the literature, a comparison is not possible since the reported performances are not comparable. A method was developed which allows for a comparison of both techniques at equal conditions, with respect to power density and energy recovery. Based on the results from the model calculations, each technique has its own field of application. Pressure-retarded osmosis seems to be more attractive for power generation using concentrated saline brines because of the higher power density combined with higher energy recovery. Reverse electrodialysis seems to be more attractive for power generation using seawater and river water. These conclusions are valid for present and latent performances of both techniques. According to the model, the potential performances of both techniques are much better than the current performances. In order to achieve these potential performances, the development of pressure-retarded osmosis must focus on membrane characteristics, i.e. increasing the water permeability of the membrane skin and optimization of the porous support. The development of reverse electrodialysis, however, must focus on system characteristics, i.e. optimization of the internal resistance, which is mainly determined by the width of the spacers.

Recycling system flexibility: the fundamental solution to achieve high energy and material recovery quotas

In order to investigate the feasibility of achieving the high material and energy recovery targets imposed by EU legislation for post-consumer goods, a fundamental material and energy recovery optimisation model has been developed. This model is used to analyze the total recycling system with the end-of-life treatment system for the car used as example to illustrate the developed principles. The model allows construction, evaluation and optimisation of different end-of-life vehicle (ELV) recovery and treatment scenarios based on a fundamental quality description of each of the flows in the system. This description makes it possible to include the physics of separation, post-shredder treatment (PST), feedstock recycling, metallurgical and thermal processings on a first principles manner in order to evaluate the system on a technical and recyclate quality basis. This fundamental description of recycling systems questions the results of life cycle assessment and similar approaches that cannot capture the physical quality of recyclates. Evaluation of various end-of-life-vehicle (ELV) processings, recovery and treatment scenarios, including (i) restricted optimisation according to the legislation and (ii) unrestricted by legislation but more market and technology driven, have shown the large negative impact on the overall recycling performance if restriction of the flexibility of processing options is too large. Flexibility of the ELV recovery and processing system permits achieving high material and energy recovery quotas (rates) (over 95%) with the use of feedstock recycling and energy recovery for organic containing fractions if they cannot be suitably physically separated. The imposed legislative restriction on the amount of material that can be directed to thermal processing for energy recovery forces the system to include additional post-shredder treatment, with the result that material and energy recovery quotas are significantly lower at 88–91%, hence creating complex waste fractions. It is interesting to note that these fundamental results support recent studies that propagate a more market driven and less quota driven system for ELV treatment. In view of complex innovative car designs it is essential that a balance is struck between feedstock recycling, physical separation, material and thermal recovery, due to the complex recyclates of possibly poor quality and economic value restricting processing. Therefore these results suggest that post-shredder treatment (PST) should be considered carefully before installing too much sophisticated separation technology in favour of energy recovery technology. PST should be attuned to future car designs and not to the present, since product complexity could make too much physical separation uneconomical. In essence, this paper argues that achieving high material and energy recovery quotas of de-polluted cars is possible if the limiting stipulation of 5 and 10% energy recovery (for 2006 and 2015, respectively) is dropped from legislation. This implies that legislation can impose high material and energy recovery quotas, but that the relevant amount of energy and material recovery should be left free to follow the dynamics of innovative product design and process operation (i.e. operational costs and market value of recyclates). Therefore the law should simply state: “ Material and energy recovery from an automobile should together reach a technological defendable maximum which implies that good business practice and the market should determine how much material and energy are recovered from the various material fractions respectively.” This should not be fixed by legislation. In addition, poor sampling statistics on data makes measurement of quotas difficult due to often lacking standard deviations, supporting such a conclusion further.

P-113: An Efficient and Cost-Effective Novel Driving Scheme for AC - PDP Sustain Driver

A new concept of an efficient energy recovery for plasma display panel (PDP) is proposed. Using a transformer in parallel with the panel capacitance, resonant current through the auxiliary switches can be reduced which results in a higher energy recovery efficiency. The validity of the proposed sustain driver established through experimental results at 200 kHz.

Differential current measurement in the BNL energy recovery linac test facility

An energy recovery linac (ERL) test facility is presently under construction at BNL [V.N. Litvinenko, et al., High current energy recovery linac at BNL, PAC, 2005; I. Ben-Zvi, et al., Extremely high current, high brightness energy recovery linac, PAC, 2005]. The goal of this test facility is to demonstrate CW operation with an average beam current greater than 100 mA, and with greater than 99.95% efficiency of current recovery. This facility will serve as a test bed for the novel high current CW photo-cathode [A. Burrill, et al., Multi-alkali photocathode development at BNL, PAC, 2005; A. Murray, et al., State-of-the-art electron guns and injector designs for energy recovery linacs, PAC, 2005], the superconducting RF cavity with HOM dampers [R. Calaga, et al., High current superconducting cavities at RHIC, EPAC, 2004; R. Calaga, et al., in: Proceedings of the 11th workshop on RF superconductivity, Lubeck, Germany, 2003], and the lattice [D. Kayran, V. Litvinenko, Novel method of emittance preservation in ERL merging system in presence of strong space charge forces, PAC, 2005; D. Kayran, et al., Optics for high brightness and high current ERL project at BNL, PAC, 2005] and feedback systems needed to insure the specified beam parameters. It is an important stepping stone for electron cooling in RHIC [I. Ben-Zvi, et al., Electron cooling of RHIC, PAC, 2005], and essential to meet the luminosity specifications of RHICII [T. Hallman, et al., RHICII/eRHIC white paper, available at http://www.bnl.gov/henp/docs/NSAC_RHICII-eRHIC_2-15-03.pdf]. The expertise and experience gained in this effort might also extend forward into a 10–20 GeV ERL for the electron-ion collider eRHIC [ http://www.agsrhichome.bnl.gov/eRHIC/, Appendix A, The linac-ring option, 2005]. We report here on the use of a technique of differential current measurement to monitor the efficiency of current recovery in the test facility, and investigate the possibility of using such a monitor in the machine protection system.

Rethinking sewage treatment by enhancing primary settling with low-dosage lime

This work presents a thorough fractionation of COD in raw sewage, followed by pilot plant coagulation tests with low-dosage lime (pH 9). Through a physical separation (sieving and crossflow filtration) total COD in the raw sewage was partitioned among eight size fractions in the range of 150-0.02 microm. In addition, respirometric tests were performed to measure the biodegradability of the different size fractions. More than 60% of COD was associated with settleable and supracolloidal particles (size > 1 microm), which are characterised by slow biodegradability. Coagulation with lime increased COD removal efficiencies in the primary treatment from typical 30-35%, up to 65-70%, suggesting that lime may induce the almost complete removal of the slowly settling, slowly biodegradable supracolloidal particles in the primary treatment. On the basis of these results a non-conventional sewage treatment scheme is proposed, considering that there is plenty of space for improving primary treatment efficiency through sewage coagulation. Higher primary treatment efficiency may present several advantages, including lower aeration energy in the subsequent biological unit and higher energy recovery from sludge digestion.

Driving forces for import of waste for energy recovery in Sweden

Between 1996 and 2002, the Swedish import of so-called yellow waste for energy recovery increased. The import mainly consisted of separated wood waste and mixes of used wood and paper and/or plastics that was combusted in district heat production plants (DHPPs). Some mixed waste was imported to waste incineration plants for energy recovery (10% of the import of yellow waste for energy recovery in 2002). The import came primarily from Germany, the Netherlands, Norway, Denmark and Finland. We identified six underlying driving forces for this recent increase of imported waste which are outlined and their interactive issues discussed. --The energy system infrastructure, which enables high energy recovery in Sweden. --The energy taxation, where high Swedish taxes on fossil fuels make relatively expensive solid biofuels the main alternative for base load production of district heat. --The quality of the waste-derived fuels, which has been higher in the exporting countries than in Sweden. --The bans on landfilling within Europe and the shortage of waste treatment capacity. --Taxes on waste management in Europe. --Gate fee differences between exporting countries and Sweden. In the future, the overall strength of these driving forces will probably be weakened. A Swedish tax on waste incineration is being investigated. In other European countries, the ambition to reach the Kyoto targets and increase the renewable electricity production could improve the competitiveness of waste-derived fuels in comparison with fossil fuels. Swedish DHPPs using waste-derived fuels will experience higher costs after the Waste Incineration Directive is fully implemented. The uncertainty about European waste generation and treatment capacity, however, might have a large influence on the future gate fees and thus also on the yellow waste import into Sweden.

SWRO core hydraulic module — the right concept decides in terms of energy consumption and reliability Part II. Advanced pressure exchanger design

By defining the combination of high pressure seawater feed pump and energy recovery system as the core hydraulic module of SWRO plants it becomes obvious that this subsystem mainly contributes to the specific water costs by its operational costs and has to be optimized by a complete approach. In the previous paper published at the IDA Conference 2003 [1], different energy recovery systems were analyzed with respect to theire overall life cycle costs. Identifying the core hydraulic module using pressure exchangers as the advantageous ERS-concept the question of appropriate component optimization was discussed for the high pressure pump design. In the current paper, this approach is extended to the pressure exchanger itself, contributing to an overall optimized core hydraulic module. Therefore, inadequacies and limits of conventional pressure exchanger operation are explored and discussed with respect to their impact on reliability. Based on these results, a new pressure exchanger design is presented. This design was realized in a laboratory prototype and tested on a special test rig. The arrangements of the test rig as well as the results of first prototype tests are described.

Pyrolysis of tire powder: influence of operation variables on the composition and yields of gaseous product

The pyrolysis of tire powder was studied experimentally using a specially designed pyrolyzer with high heating rates. The composition and yield of the derived gases and distribution of the pyrolyzed product were determined at temperatures between 500 and 1000 °C under different gas phase residence times. It is found that the gas yield goes up while the char and tar yield decrease with increasing temperature. The gaseous product mainly consists of H 2, CO, CO 2, H 2S and hydrocarbons such as CH 4, C 2H 4, C 2H 6, C 3H 6, C 3H 8, C 4H 8 and C 4H 6 with a little other hydrocarbon gases. Its heating value is in the range of 20 to 37 MJ/Nm 3. Maximum heating value is achieved at a temperature between 700 and 800 °C. The product distribution ratio of gas, tar and char is about 21:44:35 at 800 °C. The gas yield increases with increasing gas residence time when temperature of the residence zone is higher than 700 °C. The gas heating value shows the opposite trend when the temperature is higher than 800 °C. Calcined dolomite and limestone were used to explore their effect on pyrolyzed product distribution and composition of the gaseous product. It is found that both of them affect the product distribution, but the effect on tar cracking is not obvious when the temperature is lower than 900 °C. It is also found that H 2S can be absorbed effectively by using either of them. About 57% sulfur is retained in the char and 6% in the gas phase. The results indicated that high-energy recovery could not be achieved if fuel gas is the only target product. In view of this, multi-use of the pyrolyzed product is highly recommended.

P12-04 プラスチック系廃棄物のガス化発電技術に関する研究

We studied an entrained-flow gasification process which efficiently converts waste plastics to energy at a high energy recovery rate. Waste plastics, after being shredded to <10mm, were fed into an entrained-flow gasifier with air, oxygen, steam and CO_2 gas. In the gasifier, organic substances were pyrolyzed, partially combusted, and then converted into synthetic gas (CO, H_2) at a high temperature (over 1,600K). Other inert substances in the wastes such as ashes and metals were melted into slag and condensed on bag filters. The bag filters and a water scrubber removed inpurities such as dust, heavy metals, and hydrogen halides from the product gases. Solid hydrocarbons, which include char and soot, were removed at a hot cyclone and on the bag filters

Waste plastics recycling by an entrained-flow gasifier

We studied an entrained-flow gasification process which efficiently converts waste plastics to energy at a high energy recovery rate. Waste plastics, after being shredded to <8 mm or <14 mm, were fed into an entrained-flow gasifier with air and oxygen. In the gasifier, organic substances were pyrolyzed, partially combusted, and then converted into synthetic gas (CO, H2) at a high temperature (over 1600 K). The clarified gasification characteristics were that the lower heat value (LHV) of the product gas was over 4.2 MJ/Nm3 and the cold gas efficiency was approximately 60%. Other inert substances in the wastes such as ashes and metals were melted into slag and condensed on bag filters. The bag filters and a water scrubber removed impurities such as dusts, heavy metals, and hydrogen halides from the product gases. Solid hydrocarbons, which include char and soot, were removed at a hot cyclone and on the bag filters.