Pilot Plant Experiments Research Articles

Predicting the impact of underwater skimming on dissolved oxygen consumption in slow sand filters for potable water treatment

In a well-functioning slow sand filter (SSF), dissolved oxygen (DO) is crucial for enabling aerobic processes and microbiota growth. Given that DO supply is predominantly via the feed water, flow pauses (e.g., during cleaning) may trigger anoxic/anaerobic conditions in the stagnant filter bed. Underwater skimming (UWS) is an advanced cleaning technique that employs a skimmer with a shrouded blade, mounted on a mobile platform, to remove the fouling layer composed of sand and particles in order to improve the efficiency of slow sand filtration. As UWS results in changes to the flow pattern of the SSF, a mathematical model was developed to predict DO utilization after a flow perturbation associated with UWS operation. The model was based on a depth resolved measurement of specific oxygen utilization derived from a full scale SSF. Pilot plant experiments monitored DO in the feed and filtrate of SSFs cleaned using underwater and conventional dry skimming techniques. The highest oxygen utilization was in the Schmutzdecke layer, with additional demand imposed by the presence of a granular activated carbon (GAC) sandwich layer. It was observed that pseudo-steady state conditions occurred following filter ripening, where DO utilization, driven by biological activity, remained relatively constant regardless of filter cleaning technique. For flow pauses between three and 24 h, the pause duration's importance decreased, while the hydraulic loading rate became the critical factor for DO recovery in the filter. Additionally, introducing a ‘sweetening flow’ during UWS ensured a continuous DO supply, facilitating quicker DO replenishment post-cleaning. The model reliably predicted filtrate DO within ±0.6 mg/L, demonstrating its operational utility, especially in the optimisation of UWS methodology. As such, UWS can be applied to clean SSFs with the methodology modified to prevent any detrimental effects to DO management within the filter. This study predicted DO dynamics in SSFs, advancing UWS techniques and could be applied for enhancing water treatment strategies by filtration.

Enhancing flocculation kinetics assessment: Integrating aggregate size distribution into experimental and modelling frameworks

Flocculation is crucial in drinking water treatment, yet conventional techniques like jar tests may lack precision in capturing particle heterogeneity. To overcome this, a non-intrusive image-based system was employed to directly assess flocculation using aggregate size distribution (ASD). Integrating ASD into a kinetic model with a single parameter (β) allowed for tracking ASD during flocculation. Bench and pilot-plant scale experiments validated our approach. Sensitivity analysis confirmed β's responsiveness to ASD variations (r > 0.92), with modelling indicating errors averaging around 5%, underscoring its efficacy in assessing flocculation efficiency. Linking ASD coefficients from bench to pilot-scale models facilitates predicting flocculation performance.

Adaptive model forecasting of the time-variant fouling rate in dynamic ultrafiltration for produced water reclaim

The Gas and oil industry is water intensive and there is a need to develop strategies to mitigate its environmental impact. Dynamic ultrafiltration has shown remarkable performance for wastewater reclaim. However, the system complexity under uncertain input conditions limits aiming for an adaptive operation. Herein, a digital shadow tool is built for real-time adaptive model calibration and fouling rate forecasting to facilitate system operation. Previously obtained data from 18 pilot plant experiments in an oil recovery facility have been used. First, a signal preprocessing step allows the reconstruction of unrecorded backwash/backshock signals. Then, the multivariable Recursive Least Squared method with a forgetting factor using an autoregressive model (ARX) is investigated to decouple the effect of applied disturbances from the unknown input disturbances and process noise. Hyperparameters were determined through a sensitivity analysis. This approach allows accurate transmembrane pressure and membrane flux predictions (average r2>0.98 and forecasting error <10 %), matching machine learning and hybrid model prediction capabilities. Model analysis showed a correlation between model gains and the critical flux, particularly the flux setpoint. Besides, the forecasted fouling rate brought novel information regarding the onset of irreversible fouling formation. This investigation illustrates how this approach facilitates understanding the complex operation of dynamic ultrafiltration.

Pilot scale production of biodiesel from Azolla oil via heterogeneous catalysis and diesel engine analysis: kinetic and techno-economic analysis considerations

ABSTRACT The use of Azolla pinnata oil for the production of biodiesel, coupled with the use of industrial waste dolomite as a catalyst, represents a novel approach with significant potential. This innovative process offers several key advantages, such as utilizing a non-edible feedstock, reducing waste generation, and providing an alternative to fossil fuels. This research aims to investigate the viability of creating biodiesel using Azolla pinnata oil and evaluate its technical and economic appropriateness for large-scale manufacturing. A pilot plant reactor with a 10 L biodiesel capacity carries out the transesterification reaction, using dolomite from industrial waste as a heterogeneous catalyst. The reaction was conducted for 4 h at a temperature of 70°C, and biodiesel yielded approximately 99.14%. Aspen Plus is employed to simulate and design a biodiesel plant, with the reaction kinetics derived from the pilot plant reaction and inputted into Aspen Plus. Plant optimization and economic analysis are performed using the Aspen Economic Analyzer. The biodiesel blends (Azolla 20, Azolla 40, and Azolla 60) were tested in a CI engine and compared with diesel results. Based on the engine test results, the Azolla 20 blend provides less HC (12.9%), CO (13.07%), and smoke (10%) emissions; therefore, it can serve as a better alternative to neat diesel. The primary units of the proposed plant have been designed, and the process’s economic viability was determined. It was discovered that the total capital investment needed is approximately 5.054 million USD, which will be repaid within 1.97 years of operation. This research encompasses pilot plant experiments, process simulation, engine testing, and economic analysis, demonstrating the novelty, technical feasibility, and potential socio-economic impact of this biodiesel production process.

Preliminary Design of a Cryogenic System with GM Cryocooler for Testing the Hydrogen Condensers of the Distillation Columns

The Experimental Pilot Plant for Tritium and Duterium Separation has been designed and built at the Rm. Valcea National Research and Development Institute for Cryogenics and Isotopic Technologies to separate deuterium and tritium from deuterated and tritiated water based on two combined processes: catalytic isotope exchange and cryogenic distillation. For this, additional experimental stands were developed for testing different components of the columns, such as the cold box, heat exchangers, condensers, and boilers. This paper presents the design of a new generation of fin condensers that avoids film condensation and allows the dropwise condensation mode. A small-scale cryogenic system equipped with a hydrogen liquefaction unit is presented as an alternative for condenser conductivity testing. The condenser is fixed on a hydrogen tank that is protected by a radiation shield and mounted inside a vacuum chamber. The proposed method is to continuously liquefy hydrogen using a two-stage Gifford McMahon 4K cycle cryocooler. A method for estimating the liquefaction rate was proposed and confirmed by the test results.

A new approach for eliminating off-flavors from RAS fish, as part of the normal grow-out period

A new concept is presented for eliminating off-flavor from cold-water RAS-grown fish, while feeding, and as a part of the normal grow-out period. The technology is based on disconnecting the nitrification biofilter, and instead passing the water through an electrolysis system, which both oxidizes the ammonia and disinfects the water, while also removing the off-flavor compounds from the water, which thereby results in the purging of the fish. The purging period was expected to last up to 2 weeks and the fish are fed throughout it. Laboratory and pilot plant experiments were performed to prove the new concept. Lab experiments included quantification of the removal of MIB and geosmin by electrooxidation and stripping, together and separately, in the presence and absence of organic matter. A pilot plant experiment was performed using Rainbow trout to determine the rate at which the off-flavor compounds were removed from the water and the fish flesh (both skin and muscle were tested). The results show that the treatment process eliminated off-flavors in the water after ∼7 days and that the fish were below taste and odor threshold for geosmin and MIB after a maximum of 11 days. Detachment from the biofilter and the fact that the water was vigorously disinfected during the electrooxidation step guaranteed that no further off-flavor compounds would be generated during the operation. Aquacultural-management assessment indicates that RAS farms can increase both their annual production and their income by more than 10%, by implementing the suggested concept as part of the grow-out period.

Organically Bound Tritium Activity Level in Plants During Growing Season and Environmental Factor Influences

This paper presents the activity level of total organically bound tritium (OBT) in different plant species, e.g., grains (wheat, corn), trees (apple, fir), and vines, and different organs of the plants (buds, leaves, fruits, straw, and branches) surrounding the Experimental Pilot Plant for Tritium and Deuterium Separation during the growing seasons of 2020 and 2021, The influence of environmental factors over OBT in the studied plant species is established by measurements of the tritium activity level in air and precipitations and their influence over tissue-free water tritium activity.

Effect of concentration and flow rate of electrolyte on electrochemical regeneration of activated carbon at pilot-plant scale

Few research has investigated the problem of regeneration of activated carbon once it has been saturated by organic and inorganic contaminants. Among the regeneration methods, electrochemical technology is one of the most advanced, demonstrating its effectiveness in pilot-plant scale experiments using samples obtained from drinking water treatment plants. In the present study, the optimization of a parallel plate electrochemical reactor with a capacity of 15 kg of activated carbon, has been achieved regarding the electrolyte concentration and flow rate. A regeneration efficiency of approximately 90% was achieved with a 0.25 M H2SO4 concentration, while lower concentrations resulted in a voltage exceeding the acceptable limits for this type of installation. In addition, higher flow rates imply a higher recovery of the porous texture of the regenerated activated carbon. This is, to the best of our knowledge, the first report where these two experimental variables are optimized in a pilot-scale process with real saturated activated carbon samples with different types of pollutants adsorbed in the activated carbon.

Pilot Plant Experiments for Extraction of Inorganic Products from Agro Solid Waste and Cost Estimation of the Products

Pilot Plant Experiments for Extraction of Inorganic Products from Agro Solid Waste and Cost Estimation of the Products

Experimental Investigation of CECE Process to Recover Tritium and Deuterium from Low Tritiated/Deuterated Liquid Waste

A current concern of researchers from the Experimental Pilot Plant for Tritium and Deuterium Separation (PESTD) within the National R&D Institute for Cryogenics and Isotopic Technologies in Rm. Valcea is the solution of a combined electrolysis catalytic exchange (CECE) isotopic separation process that aims to be part of a new liquid waste decontamination technology. The experimental installation, defined as module M1100, has interfaces with the PESTD process and auxiliary systems and is placed within the PESTD area. The installation has its own automation and control system that allows for safe operation. Two operating modes are presented. The first mode is in “open-circuit” mode to evaluate the individual separation performances of the two technological processes, water electrolysis and water-hydrogen catalytic isotopic exchange, respectively. The second mode is in “closed loop,” which corresponds to the CECE isotopic separation process where the tritium/deuterium are concentrated in the water within the electrolyzer. The preliminary experimental investigations were performed with low-concentrated tritiated water (HTO; ~100 Bq/l] in order to have a reduced degree of contamination as the concentration of the processed water was increased (~1000 Bq/l). The evaluation of the separation performances was made by comparing correlations from direct measurements with the calculated ones provided by the software developed for the CECE isotopic separation process in the open-circuit operating mode. For the closed-loop operation mode, the data provided by the calculation program for the representation of the nonstationary CECE isotopic separation regime were compared with the measured data. The preliminary results show a good correlation between the measured and the calculated data considering these experiments were carried out mainly in order to improve the operating performance.

Development of a cooling and power generation prototype integrating an axial micro-turbine in an absorption chiller

The integration of an expander in an absorption machine allows it to produce cooling and electricity simultaneously within the same cycle. This technology holds great potential to harness low-temperature heat sources more efficiently than production with separate cycles. However, very few experimental studies on absorption combined cooling and power production cycles can be found in literature. In order to achieve an in-depth understanding of this technology and of the interactions between power and cooling production sides of the circuit, the integration of an expander into a single stage ammonia water absorption chiller was undertaken through the development of an experimental pilot plant. The peculiar characteristics of the expansion device, as well as the use of a newly developed combined desorber avoiding the presence of a rectifier make the prototype built unique. Design and integration of the expander proved to be very challenging, mainly due to the small size of the application and corrosiveness of the ammonia water mixture. Significant electricity generation losses experienced lead to maximum electrical efficiency of 7% and corresponding maximum power production around 33 W at a lower than expected rotational speed of 20′000 rpm.Despite these difficulties, first experimental measurements have been obtained, giving interesting insights on the functioning of the cycle. Indeed, the impracticability of regulating the ratio between cooling and power production was highlighted, due to the characteristics of the impulse turbine. Opening of the turbine line in the nominal point leads to a reduction of the mass flow rate passing through the cooling line of 65% (i.e., split ratio of 0.35) and a cooling power output decrease of around 57% (from 4.9 to 2.1 kW). Additionally, diverting some of the desorbed vapour to the power production line has important effects on the pressure equilibrium and circulating vapour mass flow rate, increasing from 16.1 kg/h in the simple absorption working mode to 31.1 kg/h in the combined mode in the nominal operating point. Feedback from the pilot plant will be very useful for the further development of the technology.

The Influence of Configuration Parameters of the Planetary Drive of Crank Presses on its Dynamic and Energy-Consumption Characteristics

Introduction. The planetary drive has been widely found in the activation systems of crank presses as it improves working conditions of friction units and reduces press metal consumption and energy consumption.Problem Statement. For studying the planetary motion of its main parts, it is advisable to consider its operation as four periods characterized by different patterns of changes in external loads and, consequently, different patterns of motion of core parts. The periods between switching the brakes when one link has not stopped, while other one starts moving is of the greatest interest. The problem of dynamic and energy-consumption parameters of the drive in transient conditions still remain a little open.Purpose. The purpose of this research is to qualitatively assess the influence of configuration parameters on the dynamics of the processes of switching and stopping the planetary drive.Material and Methods. The parameters of the experimental pilot plant, a model planetary drive with a nominal load of 400 kN, have been calculated. The minimum speed of the central gear has been estimated depending on the moments of inertia of the leading mass and the outer gear. The obtained dependences have been processed with the use of a standard mathematical apparatus.Results. It has been found that the energy-consumption and dynamic parameters of the drive are significantly influenced by such characteristics as moments of inertia and braking moments, while decreasing angular velocity of the drive flywheel does not depend on the moments of inertia of the stopped links. The rate of braking processes is determined by the elastic properties of the friction materials and the parameters of the brake springs, not by the parameters of compressed air outflow.Conclusions. The obtained analytical and graphical dependences have allowed not only qualitative, but also quantitative assessment of the influence of the parameters on the dynamics of processes. These recommendations can be used at the design stage, to select the optimal parameters of the drive with the predicted properties.

Innovative technology for ammonia abatement from livestock buildings using advanced oxidation processes

The feasibility of using advanced oxidation processes (AOPs) for abatement of ammonia from livestock buildings was examined in a series of pilot plant experiments. In this study, all the experiments were conducted in a two-step unit containing a dry photolytic reactor (UV185/UV254/O3) and a photochemical scrubber (UV254/H2O2). The unit efficiency was tested for two initial ammonia concentrations (20 and 35 ppmv) and three different air flows (150, 300 and 450 m3·h−1). While the first step removes mainly organic pollutants that are often present together with ammonia in the air and ammonia only partially, the second step removes around 90% of ammonia emissions even at the highest flow rate of 450 m3·h−1. Absorbed ammonia in the aqueous phase can be effectively removed without adjusting the pH (i.e. without the addition of other additives) using UV and ozone. Complete removal of ammonia was achieved after 15 h of irradiation. In order to assess the price efficiency of the suggested technology and to be able to compare it with other methods the figures-of-merit were determined. The price needed for lowering ammonia emission by one order of magnitude is 0.002 € per cubic meter of treated air at the highest flow rate of 450 m3·h−1 and for initial ammonia concentrations of 20 ppmv. These findings demonstrate that AOPs are a promising method for ammonia abatement from livestock buildings which are rarely using any waste air treatment method.

Synthetic oxygen carrier C28 compared to natural ores for chemical looping combustion with solid fuels in 80 kWth pilot plant experiments

Chemical Looping Combustion (CLC) is a highly efficient CO2 separation technology with no direct contact between combustion air and fuel. A metal oxide is used as oxygen carrier (OC) in a dual fluidized bed to generate clean CO2. The use of solid fuels, especially biomass, is the focus of current research, because of the possibility of “negative” CO2-emissions. The OC is a key component, because it must meet special requirements for solid fuels, which are different to gaseous fuels. Most frequently naturals ores or synthetic materials are used as OC. Synthetic OC are characterised by higher reactivity at the expense of higher costs. For this reason, so far not so many experiments have been conducted on a larger scale with synthetic OC on solid CLC. This work deals with the synthetic perovskite C28 and investigating the suitability as oxygen carrier in an 80 kWth pilot plant for chemical looping combustion with biogenic fuels. The experiments show a significantly increased combustion efficiency of 99.6 % compared to natural ores and a major influence of the solid circulation rate on general performance, whereby carbon capture rates up to 98.3 % were reached. Furthermore, the role of the fuel reactor's counter-current flow column and its impact on better gas conversion was investigated. C28 suffered no deactivation or degradation over the experimental time, but first traces of ash layer formation, phase shifting and attrition of fines could be detected. The focus of further research should lie on long-term stability and reactivity for their high impact on the economic scale up of C28.

THE IMPACT OF EXPERIMENTAL PILOT FOR TRITIUM AND DEUTERIUM SEPARATION ACTIVITY ON TRITIUM LEVEL IN THE ATMOSPHERIC WATER VAPOR OF ICSI TRITIUM LABORATORY

Results obtained from the monitoring of the ambient air of the ICSI Ramnicu Valcea Tritium Laboratory and the monitoring of the atmosphere around the Experimental Pilot Plant for Tritium and Deuterium Separation are used in the environmental impact evaluation of the experiments in the period 2020-2022. Even though the experiments carried out involved different tritium activity concentrations, there were no increases in the activity of tritium concentration in the analyzed samples, with numerous results of atmospheric samples being below the detection limit.

Removal of organic micropollutants from municipal wastewater by powdered activated carbon - activated sludge treatment

In Powdered Activated Carbon (PAC)-Activated Sludge (AS) Treatment, PAC is directly dosed into the AS tank. In this study, batch and pilot plant experiments were carried out to investigate the efficacy of PAC-AS treatment concerning the removal of organic micropollutants (OMPs). Batch and pilot plant experiments showed comparable removal efficiency of nine OMPs: a mean removal of 80 % could be achieved at a specific PAC dose of 2.5 mg PAC/mg DOC; during a PAC cut-off experiment, the removal performance leveled off in the first 6 h without PAC dosage. A further investigation involving an intermittent dosage of PAC demonstrated that OMPs were removed stably when PAC was dosed every 6 h, which implies the possibility of reduced investment and maintenance costs of a dosing unit.DOC was removed by 18 ± 4 % when the PAC doses ranged from 1.9 to 2.3 mg PAC/mg DOC in this study. A more detailed characterization of the organic matter was performed by means of size exclusion chromatography coupled with organic carbon detection (SEC-OCD). The high molecular weight fraction (F1) and hydrophobic organic compounds (DOCh) were most adsorbed by PAC, revealed by batch and pilot plant experiments. It indicates a higher competition potential of these two fractions against OMP adsorption compared to other DOC fractions in the PAC-AS system.

Factors affecting the catalytic oxidative removal of soluble manganese in natural water by superfine powdered activated carbon and free chlorine

Catalytic oxidation of dissolved divalent Mn ion (Mn2+) by free chlorine and superfine powdered activated carbon (SPAC) before microfiltration has been emerged as a new technology to remove Mn from natural water for drinking water production. However, Mn was not sufficiently removed in pilot-plant experiments yet. The present study clarified underlaying removal mechanisms. In natural water, soluble Mn exists as colloidal Mn with a molecular weight ≥ 10,000 Da in the oxidized form in addition to Mn2+. Mn2+ was removed by SPAC‑chlorine, but Ca2+, Mg2+, and NOM decreased the Mn2+ removal rate as a result of competitive adsorption. The colloidal Mn was not removed by SPAC‑chlorine, but could be removed by coagulation and microfiltration or ultrafiltration alone. With the addition of coagulant (poly‑aluminum chloride), the soluble Mn concentration increased because of redissolution of precipitated-oxidized Mn due an increase in local acidity, in particular at low temperature, and coagulation reduced soluble Mn removal rate due to hindrance of mass transfer. These negative impacts may be partially attenuated by using high-intensity mixing or waiting to add the coagulant after the oxidation of Mn2+ has progressed sufficiently. Mn removal rate changed with temperature and mixing intensity in the same trend as predicted by the mass-transfer model, but it was smaller than the prediction. Together with the effects of Ca2+, Mg2+, and NOM, it appears that not only mass transfer but also the process of adsorption is a factor affecting the overall Mn removal rate.

Performance and economic analysis of a solar membrane distillation pilot plant under various operating conditions

Although membrane distillation (MD) is a promising desalination process, its use is limited because it requires a large amount of thermal energy. To reduce the thermal energy consumption during MD, studies combining various renewable energy sources (e.g., solar, geothermal, and waste heat) are currently being conducted. Therefore, pilot plant experiments combining solar energy with an MD system were conducted. In particular, a module that could be changed into different MD configurations, including direct contact MD (DCMD) and air gap MD (AGMD), was reviewed. The performance of the pilot plant was analyzed for each configuration under various operating conditions and according to onsite weather conditions. Because DCMD can obtain a 43% higher water flux than can AGMD, a long-term DCMD test was conducted to achieve a high water flux. The specific energy consumption (SEC) and gained output ratio (GOR) were compared in the presence and absence of solar energy. A 30% decrease in the SEC and 17% increase in the GOR were observed for the sunny days compared with when no solar energy was used. These results indicate that combining the MD with solar energy can improve its performance during long-term operation. In addition, the cost per unit volume of product water was estimated based on the designed solar MD pilot plant.

System analysis methods and resource-saving electromembrane technologies in creating a low-flow water system using of Tatarstan Republic energy facilities

THE PURPOSE. theoretical substantiation of resource-saving technologies and development of "terminal" electromembrane installations when creating a low-flow water use system for energy facilities of the Republic of Tatarstan.METHODS. In the work, the methods of system analysis were used and a mathematical model was developed to describe it. The description and technical characteristics of the developed devices and installations for testing the proposed technologies are presented.RESULTS. At Kazan CHPP-3, a technology was developed and a pilot electromembrane plant was installed for the disposal of blowdown water from the thermal desalination complex. As a result of the operation of the electromembrane unit, a transparent alkaline solution is formed with a pH of 13.86 and a concentration of OH ions of 2.7% (up to 4%). The content of salt components in the concentrate is 2% by weight. The resulting concentrated alkaline solution can be used in the cycle of the station for the regeneration of anion exchange filters of the 1st stage. The softened saline solution is fed to the heating network. The electromembrane plant processes 0.5 tons per hour of alkaline wastewater with a ratio of concentrated alkaline solution to softened brine of 1:9. The specific power consumption is 6 kWh per 1 ton of blowdown water. The operation of the plant is characterized by the complete absence of waste and bezreagnosti. At the ion-exchange water treatment plant of the Nizhnekamsk CHPP-1, a method was proposed, a technology was developed, and an experimental pilot plant was installed for processing alkaline spent regeneration solutions of anion-exchange filters. The electromembrane plant processes 1.5 tons per hour of alkaline waste. The capacity of the plant is 0.1 tons of 4% alkaline solution. Specific power consumption - 4 kWh per 1 ton of alkaline waste solutions. During the operation of the installation, there is a complete absence of waste with a reagent-free wastewater disposal process.CONCLUSION. The return of regenerated alkali solutions and softened water to the production cycle makes it possible to obtain a significant improvement in indicators that characterize environmental friendliness and resource saving without the use of chemical reagents.

Redesigning the Production Process Using Simulation for Sustainable Development of the Enterprise

In this case study, the medium-sized enterprise is looking for ways to achieve sustainable development. Following the Industry 4.0 trend could get the enterprise closer. The rate of information technology usage is very low in the enterprise. The enterprise’s problem is the long production of orders. The orders had to be rejected many times because the customer’s time limit could not be met. The major cause seems to be two environmentally insufficient and obsolete machines in the blast cleaning operation. These machines are replaced in the production by one new wheel blast machine. However, the production process must be redesigned and the layout changed to use this machine effectively. This redesign is difficult to verify and evaluate in the pilot plant experiment. Simulation is the most suitable tool to do it quickly and relatively easily. The ExtendSim simulation program creates a real production process model and then applies the redesign of this process in the model. The model must be thoroughly verified concerning the real production process to not distort the results. The result of the redesign of the production process is the reduction of the production duration by almost 50% and elimination of two environmentally insufficient and obsolete machines. Improved machine blast cleaning has also significantly reduced the utilization of blast cleaning. Spared capacities can be used for pre-production or otherwise for the profit-making of the enterprise. However, a new bottleneck appeared elsewhere in the production process by removing the previous one. The innovation passed through barriers, and Slovak small and medium enterprises started building sustainable development. The enterprise still must focus on further innovation, and more investment will be needed to achieve the final sustainable development goal.