Modified Operating Conditions Research Articles

Assessment of the Impact of a New Industrial Discharge on an Urban Wastewater Treatment Plant: Proposal for an Experimental Protocol

Assessing the compatibility of industrial discharges with the biological process of a municipal wastewater treatment plant (WWTP) may represent a critical task. Indeed, either focusing only on chemical characterization or ecotoxicity tests designed to assess the impact on surface waters may lead to questionable or misleading conclusions. The feasibility of an industrial connection to the sewer should better take into account the features of the downstream WWTP, in particular by studying the potential effects on the biomass of that specific plant. With this aim, a multi-step experimental protocol applicable by water utilities has been proposed: (step 1) calculation of the flow rate/load ratio between industrial discharge (ID) and urban wastewater (WW); (step 2) analysis of the modified operating conditions of the biological stage; (step 3) experimental assessment of the impact of the ID on the WWTP biomass by means of respirometric tests. An application of this protocol is presented in this work as a case study, namely a new ID (average flowrate 200 m3 d−1) coming from an aqueous waste treatment plant (AWTP) to be connected to the public sewer. The integrated evaluation of results showed that no negative impacts could be expected on the downstream urban activated sludge WWTP (treating a flow rate of around 45,000 m3 d−1).

Accelerating urea hydrolysis in fresh urine by modifying operating conditions of a sequencing batch reactor

ABSTRACT A number of existing and emerging technologies can recover nitrogen from urine. A preliminary step in many nitrogen recovery processes is hydrolyzing urea to ammonium, a biologically-mediated process that can take days to weeks without intervention. The ability to achieve urea hydrolysis quickly and reliably would increase the feasibility of decentralized nitrogen recovery, especially where space and treatment time are constrained. The goal of this research was to determine whether urea hydrolysis could be accelerated by providing an inoculum containing microorganisms likely to have urease activity (feces or soil), providing a carrier to support attached growth (plastic carriers, granular activated carbon, or no carrier), and modifying the hydraulic retention time (HRT; 1.3, 2, and 4 days) and feeding frequency (Δt = 4, 24 h). Inoculated reactors achieved significantly more urea hydrolysis, and reactors inoculated with soil were able to sustain higher urea hydrolysis rates over time than those inoculated with feces. The mean zero-order rate constants (mM/hr) for reactors with a soil inoculum (15.1) were about three times higher than that of reactors with an inoculum of feces (4.9). A reactor with GAC and an inoculum of soil fed daily with fresh urine achieved greater than 90% hydrolysis with an HRT of 2 days; results suggest the HRT could be reduced to 16 h without reducing performance. No significant benefit was provided by increasing the frequency of feedings for the same HRT, likely because urease enzymes were saturated and operating at maximum hydrolysis rates during most of the reaction period.

Physics-Based Methods and Tools for Rapid Classification, Quantification, and Forecasting of Lithium-Ion Battery Aging Modes and Life

Physics-based methods and tools for rapid classification, quantification, and forecasting of lithium-ion battery aging modes and life Sangwook Kim,1 Zonggen Yi,1 Ross R. Kunz,1 Eric J. Dufek,1 Tanvir Tanim,1 Kevin L. Gering1, Bor-Rong Chen,1 Peter Weddle, 2 Kandler Smith, 2 1 Energy and Environmental Science and Technology, Idaho National Laboratory, Idaho Falls, Idaho 83415 USA 2 Center for Energy Conversion & Storage Systems, National Renewable Energy Laboratory, Golden, CO 80401, USA 242nd ECS Meeting, Atlanta, GA, Oct. 9 - 13, 2022 Symposium: A03 – Lithium Ion Batteries Lithium-ion batteries play a central role in powering electric vehicles, stationary energy storage systems, and consumer electronics. Lately, machine learning and deep learning (DL) has been successfully used to gain insights into battery degradation during battery operation and predict lifetime in battery research and development community. Fast and robust classification and quantification of battery aging (e.g., Loss of Lithium Inventory (LLI) and Loss of active Material (LAM)) and accurate long-term forecasting of battery life enable more proactive planning of battery management and preemptive actions of modified operating conditions to achieve safe operations and prolong battery life.Here, we present the development of Incremental Capacity (IC)-DL framework for fast charging conditions as a diagnostic tool for aging mode classification and quantification (Figure 1). The classification and quantification of dominant battery aging modes is conducted using a synthetic-data-based DL modeling framework. Over 6000 initial conditions and 26,000 different aging conditions are generated using IC model to train DL. We applied trained DL classification and quantification algorithm to 22 Gr/NMC532 pouch cells with a different loading and charging protocol tested up to 600 cycles. Besides the analysis of reference performance test data at C/20, cycle-by-cycle data at higher C-rate is analyzed. This IC-DL framework as a diagnostic tool is also used in different battery chemistries, such as Gr/NMC811and LTO/LMO. IC-DL framework enables unique, rapid identification and quantification of the dominant aging modes at different C-rates in different battery chemistries. Additionally, a prognostic tool, Sigmoidal Rate Expression (SRE)-type mathematics are employed to evaluate the capacity loss and aging mode (i.e., LLI). SREs are robust engines that contain three variables that capture the thermodynamic and kinetic “thumbprint” of the mechanism progression within the context of a batch reactor scenario [1].We show two different methods by which SRE parameters can be early assessed based on quantified values from IC-DL framework; (1) extrapolative techniques using specialized functions to determine SRE parameter convergence and (2) a technique based on deep learning and Monte Carlo framework. Overall results from both methods confirm that we can predict capacity loss and LLI at the end of test (i.e., 600 cycles) within 1-2% absolute error using three weeks of testing data (or 125 cycles). We believe the IC-DL framework combined with SRE-base prognostics will reduce lithium-ion batteries development cycle as well as shorten the turnover time for validation, fulfilling the demands of rapidly growing battery market. References K. Gering, Electrochimica Acta, 228(20), 636-651 (2017) Figure 1

A knowledge transfer framework to support rapid process modeling in aerosol jet printing

Aerosol jet printing (AJP) technology recently gained considerable attention in an electronic manufacturing industry due to its ability to fabricate parts with fine resolution and high flexibility. However, morphology control has been identified as the main limitation of AJP process, which drastically affects the electrical performance of printed components. Even though previous researches have made significant efforts in process modeling to improve the controllability of the the printed line morphology, the modeling process is still inefficient under modified operating conditions due to the repeated experiments. In this paper, a knowledge transfer framework is proposed for efficient modeling of the AJP process under varied operating conditions. The proposed framework consists of three critical steps for rapid process modeling of AJP. First, a sufficient source domain dataset at a certain operating condition is collected to develop a source model based on Gaussian process regression. Then, the representative experimental points are selected from the source domain to construct a target dataset under different operating conditions. Finally, classical knowledge transfer approaches are adopted to extract the built-in knowledge from the source model; thus, a new process model can be developed efficiently by the transferred knowledge and the representative dataset from the target domain. The validity of the proposed framework for the rapid process modeling of AJP is investigated by case study, and the limitations of the classical knowledge transfer approaches adopted in AJP are also analyzed systematically. The proposed framework is developed based on the principles of knowledge discovery, which is different from traditional process modeling approaches in AJP. Therefore, the modeling process is more systematic and cost-efficient, which will be helpful to improve the controllability of the line morphology. Additionally, due to its data-driven based characteristics, the proposed framework can be applied to other additive manufacturing technologies for process modeling researches.

Modelling methodology of temperature and energy consumption in food plant: Application to puff pastry

• This study focuses on a food plant of puff pastry. • A thermal and energy modelling approach was developed. • Industrial own-check data were mainly used. • The thermostat setting temperature can be raised in this application. This study focuses on the experimental and numerical characterization of the food temperature and energy consumption of cold facilities in a food processing plant. An event based framework was used to model the main components of the production line (kneader, conveyor, cooling spiral and cold room). Plant self-control data obtained by measurement in plant were used to inform and validate the model. Different scenarios were tested to evaluate the impact of modified operating conditions (thermostat setting temperature and duration) and refrigerating equipment outages on energy consumption and food temperatures. Up to 18% of energy savings could be achieved by increasing thermostat setting temperature of the process room and the storage room with a limited impact on the product temperature. This methodology can help manufacturers in decision making to optimize operating conditions and reduce energy consumption with a limited impact on food waste and safety.

Simulation Analysis of a Mineral Liberation Estimator for Control Purposes

Abstract In the past few decades, extensive and intensive work has been done in the field of optimisation and control for mineral processing plants. As the valuable minerals have to be separated from the gangue through grinding, one of the most crucial process variables to monitor is the particle size. Although great advances have been accomplished, the vast majority of the proposed strategies relies on the control of a given product size index. The ultimate goal of comminution is mineral liberation, and it is not exclusively dependent on particle dimensions. Approaches focusing on liberation control rather than particle size could thus provide significant advantages. However, online measurement or estimation of mineral liberation is challenging to say the least. In this regard, there is still no work reported in the literature on the use of mineral liberation for online optimisation and control. This article explores the use of a mineral liberation distribution estimator for process control by investigating the effect of changing material properties and plant operating conditions. First, ore characteristics such as size distribution, mineral grades and grain sizes are varied to assess their impact. Then, the estimator is implemented as a liberation sensor in a simulated grinding circuit to observe the effect of modifying operating conditions. The results give a preliminary insight on the possibilities of using mineral liberation information for process control and optimisation purposes.

Modifying Operating Conditions of the Friction Pair with an Additive Added to the Lubricant while Operating

This paper presents the results of research into the effect of the use of an additive to the lubricating oil SAE 15W/40 on the lubricating properties (standardised tests), i.e. the weld point Pz, last non-seizure load Pn, load-wear index Ih, and seizure load Pt. The friction pair consisted of four balls and the tested lubricant. Moreover, the impact of the use of the lubricating oil (non-standardised tests) on tribological properties such as friction force, wear, and the temperature of the friction area for the friction pair C45 steel/210Cr12 steel, was explored. The additive contained copper and lead particles of the size of a few micrometers. The tests helped to determine the effect of the use of the additive to the lubricant on the formation of the operational surface layer. The results were used to build a model of the boundary layer formed as a result of the additive to the lubricating oil.

Techniques for hot embossing microstructures on liquid silicone rubbers with fillers

Embossing is an established process for the thermoplastic elastomers but not yet for the thermosetting elastomers. It has already been shown that hot embossing is a viable technology for imprinting microstructures in addition to curing thin silicone films at their gel point. It is one of the simplest, most cost-effective, and time-saving methods for replicating microstructures. In the present study, films made from liquid silicone rubber (LSR) formulations containing fillers are hot embossed under modified operating conditions. The use of such relatively hard silicone elastomers shows the versatility of this method that has been established for softer silicone elastomers. Also, as a proof of concept, a microstructured metal (nickel (Ni)) plate is used as an embosser for the films successfully. The ideal condition for hot embossing the LSR formulation (XLR 630 with titanium dioxide fillers) with a Ni embosser is 110°C preheating for 15–35 s, embossed with 2 bar pressure, and postheating for complete curing at 110°C for 3 min showing that the process is extremely fast.

Mathematical model of a plate fin heat exchanger operating under solid oxide fuel cell working conditions

Abstract Heat exchangers of different types find application in power systems based on solid oxide fuel cells (SOFC). Compact plate fin heat exchangers are typically found to perfectly fit systems with power output under 5 kWel. Micro-combined heat and power (micro-CHP) units with solid oxide fuel cells can exhibit high electrical and overall efficiencies, exceeding 85%, respectively. These values can be achieved only when high thermal integration of a system is assured. Selection and sizing of heat exchangers play a crucial role and should be done with caution. Moreover, performance of heat exchangers under variable operating conditions can strongly influence efficiency of the complete system. For that reason, it becomes important to develop high fidelity mathematical models allowing evaluation of heat exchangers under modified operating conditions, in high temperature regimes. Prediction of pressure and temperatures drops at the exit of cold and hot sides are important for system-level studies. Paper presents dedicated mathematical model used for evaluation of a plate fin heat exchanger, operating as a part of micro-CHP unit with solid oxide fuel cells.

Influence of a nonaqueous phase liquid (NAPL) on biodegradation of phenanthrene

A series of batch reactor experiments was carried out to examine the effect of a nonaqueous phase liquid (NAPL) on the biodegradation of a hydrophobic solute. A mathematical program model that describes physical processes of solute solubilization and partitioning between the NAPL and aqueous phases as well as microbial degradation and oxygen utilization was used to analyze the test data. The model calculates the cumulative changes in concentration of substrate, cell mass, carbon dioxide, and dissolved oxygen as a function of time. The equations incorporate the effects of solute solubilization, partitioning, biodegradation, as well as oxygen availability. Hexadecane was used as the model NAPL and was not biodegraded in the timeframe of the experiments performed. The model solute was the polyaromatic hydrocarbon, phenanthrene. In agreement with several previous studies, experimental measurements showed that hexadecane increased rates of mineralization of 15 mg phenanthrene when present at low mass but decreased rates at high mass. Model results suggest that partitioning of the phenanthrene into the hexadecane phase limits bioavailability at high NAPL mass. Further the model suggests that mineralization rates were higher with the low NAPL mass because aqueous phenanthrene concentrations were higher in those treatments from ca. 20 to 40 h than in other treatments. Finally, experiments showed that the presence of hexadecane, at all masses tested, resulted in a lower cell yield, effectively increasing the amount of CO(2) produced during the experiment. Model results suggest that this is due to changes in phenanthrene metabolism that are induced by the presence of the hexadecane phase. Model studies aimed at increasing rates of biodegradation by modifying operating conditions are described along with practical approaches to implementing these modifications.

Change in metabolism of PHA accumulation by activated sludge modifying operating conditions

In the present work, sludge from a stable and efficient phosphorus removal process was used to evaluate the change in the metabolism when the reactor operation was modified from anaerobic/aerobic to aerobic dynamic substrate feeding. The change in operational conditions allowed the population to modify the metabolism of phosphorus and polyhydroxyalkanoates (PHA) accumulation. Under aerobic dynamic feeding, phosphorus accumulation was almost hindered while the amount of PHA accumulation increased significantly. After ten days of operation under dynamic substrate feeding, the reactor operation turned back to anaerobic/aerobic cycles and the metabolism of phosphorus was progressively recovered.

Optically coupled CCD transversal filter with several hundreds of coefficients at megahertz sampling rates

Under modified operating conditions, a CCD imager arrangement is used as a hybrid optoelectronic transversal filter. The principles are explained and an example of application is provided. In comparison with solutions in common use, the number of coefficients and the sampling rate are increased by several decades.

MODIFICATION OF CORN WET-MILLING STEEPING CONDITIONS TO REDUCE ENERGY CONSUMPTION

Laboratory corn wet-milling experiments were conducted with modified operating conditions. Mill-starch yield obtained from corn steeped at reduced steep solution volume was comparable to normal operation as long as the absolute amount of steeping agent, SO2, remained the same. Increasing the SO2 concentration or removing the mass transfer barriers between the endosperm and the steep solution by degerminating between two steeping periods improved mill-starch yield. These modifications have potential for saving energy consumed in steeping and in concentrating residual steep solution.

Effects of Tilt on the Performance of Hydrostatic Thrust Pads

The majority of hydrostatic thrust bearings are designed on the assumption that the bearing surfaces are parallel but, with the possibility of manufacturing and assembly errors and structural deformations, this condition is rarely, if ever, achieved in practice. With the increasing demands being made in modern machinery, more detailed design information is required. An experimental and theoretical investigation was carried out into the effects of tilt on the operation of circular hydrostatic thrust pads, the results of which show that, for static conditions, the characteristics of a tilted pad can be reliably predicted, assuming the lubricant to be isoviscous. With this information, a thrust pad can be designed to operate in any specified tilted configuration or can be incorporated in a rigorous structural design. In many applications, however, it may be difficult to specify the tilt and in such situations it is more useful for the designer to have some indication of how the operating conditions may be modified by tilt when the design is based on parallel surfaces. For a system which is supplied from a constant pressure source through a viscous external restrictor, the modified operating conditions can be predicted. The effect of tilt on the operating conditions depends on the pad geometry and design resistance ratio but significant changes may occur in mean pad clearance, required flow rate and static stiffness. Although this investigation was limited to static conditions, the results are still valid for sliding conditions where the hydrodynamic effects are small compared with the hydrostatic contribution. The general effects of tilt observed with circular pads are indicative of what may be expected with pads of other geometries.

The operation of large turbo-alternators to reduce rotor winding deformation

The failure of turbo-alternator rotors as a result of copper distortion now constitutes a major cause of outage of electrical generating plant and calls for a closer investigation of the causes of such distortion. The authors expand existing theories based on the work-hardening of copper by temperature cycles and give data of the plastic deformation of copper at working temperatures. The results are given of measurements of both temperatures and the stresses in the windings on alternator rotors in service. An analysis of the phenomena causing the stressed condition indicates means for controlling the stresses. The authors describe the modified operating conditions which have been adopted and some of the difficulties arising therefrom, as well as the equipment installed to measure and control the temperature of alternator-rotor windings. A brief reference is made to the economics of the problem.

The operation of large turbo-alternators to reduce rotor winding deformation

The failure of turbo-alternator rotors as a result of copper distortion now constitutes a major cause of outage of electrical generating plant and calls for a closer investigation of the causes of such distortion.The authors expand existing theories based on the work-hardening of copper by temperature cycles and give data of the plastic deformation of copper at working temperatures.The results are given of measurements of both temperatures and the stresses in the windings on alternator rotors in service. An analysis of the phenomena causing the stressed condition indicates means for controlling the stresses.The authors describe the modified operating conditions which have been adopted and some of the difficulties arising therefrom, as well as the equipment installed to measure and control the temperature of alternator-rotor windings. A brief reference is made to the economics of the problem.