Pilot Plant Installation Research Articles

Experimental Performance Comparison of High-Glide Hydrocarbon and Synthetic Refrigerant Mixtures in a High-Temperature Heat Pump

Several theoretical studies have predicted that refrigerant mixtures with glides of more than 20 K can yield COP improvements in heat pumps for operating conditions where the temperature difference between the heat source and heat sink is large, but experimental validations and quantifications are scarce. The application of high-glide mixtures (>20 K) in industrial heat pumps in the field is, therefore, still hampered by concerns about the behavior and handling of the mixtures. This study experimentally investigates hydrocarbon (HC) mixtures R-290/600 (propane/butane) and R-290/601 (propane/pentane) and compares them to previously tested mixtures of synthetic refrigerants. Comprehensive evaluations are presented regarding COP, compressor performance, pressure drop, heat transfer, and the possibility of inline composition determination. The mixtures were tested over a range of compositions at a source inlet temperature of 60 °C and a sink outlet temperature of 100 °C, with the heat sink and heat source temperature differences controlled to 35 K. R-290/601 at a mass composition of 70%/30% was found as the best mixture with a COP improvement of 19% over R-600 as the best pure fluid. The overall isentropic compressor efficiency was similar for HC and synthetic refrigerants, given equal suction and discharge pressures. Pressure drops in heat exchangers and connecting lines were equal for synthetic and HC mixtures at equal mass flow rates. This allows higher heating capacities of HC mixtures at a given pressure drop (mass flow rate) due to their wider vapor dome. A previously developed evaporator heat transfer correlation for synthetic refrigerant mixtures was applicable to the HC mixtures. A condenser heat transfer correlation previously fitted for synthetic refrigerants performed significantly worse for HC mixtures. Composition determination during operation and without sampling was possible with a deviation of at most 0.05 mass fraction using simple temperature and pressure measurements and REFPROP for thermodynamic property calculations. Overall, high-glide HC mixtures, just like mixtures of synthetic refrigerants, showed significant COP improvements for specific operating conditions despite a decreased heat transfer coefficient. Potential problems like composition shift or poor compressor performance were not encountered. As a next step, testing high-glide mixtures in pilot-plant installations is recommended.

Performance of rotational speed controlled small-scale head-dependent hydroelectric power plant

Small scale or micro scale hydroelectric power production is characterized by high investment costs compared to operation costs. In addition, the repayment time is often long, more than ten years (if not subsidized heavily) which requires that a small-scale hydropower plants can be profitable only if both the investment costs and the running costs are low. The performance and efficiency of a plant is very important because having long repayment time means that the efficiency improvement of one percentage unit often means the ten percentage unit improvement in profit. The most economical way to control the flow is sometimes a two point control where generators are switched on and off depending on high water level used as control variable. The water level cannot be kept constant using this method, but the traditionally used mechanical blade angle adjustment system is too expensive in very small (approximately <100 kW) units. The new method of controlling the upper water level (head) is the use of rotational speed control of turbine, implemented by a four quadrant frequency converter. The efficiency of a 4-quadrant frequency converter is approximately 97 %, which reduces the income compared to the situation where the generators are directly connected to electricity network. However, when the head is kept constant using a frequency converter, it is not required to switch off the generator circuit breakers which have a finite life time and the head height can be kept optimal in terms of performance. In this paper, a system structure, a pilot plant installation and example calculations on the feasibility of a frequency converter driven fixed blade hydro power turbine is given.

Utilizing of sunflower seed husk through production of biochar and its application in systems for purification of water contaminated with cadmium

The pollution of water streams is one of the most spread environmental problem whole the world due to its permanently increasing from one part, and the importance of water for the human health from the other. An approach for decontamination of polluted waters based on the ideology of the circular economy is investigated in this study. The wasted sunflower seed husks obtained during the cooking oil production were subjected to gasification process in pilot plant installation. Three biochar samples were obtained and characterized regarding main properties like carbon content, moisture, ash, volatile compounds, and specific surface area at different experimental conditions. For all samples was possessed high carbon content of 69-75 wt. % and well developed surface area of 262-321 m2/g. The biochar materials were subjected to experimental procedure for evaluation of their potential for adsorption of cadmium (Cd) ions from water solution with different concentration of the pollutant. The obtained reduction coefficient for all biochar samples reached up to 99.97 % for the initial concentration of Cd-ions from 1.1 mg/l to 562 mg/l. For the higher Cd concentrations in the range of 1124-11240 mg/l, the reduction decreased to 11-24 %. The highest adsorption capacity of 289.99 mg/g is obtained for the biochar sample subjected to gasification for 2 minutes.

Scaled-up and economic assessment approach of the split-phase glycolysis process for the recycling of flexible polyurethane foam wastes

The economic viability of the split-phase glycolysis process for the recycling of any kind of flexible polyurethane foam waste employing crude glycerol as cleavage agent has been demonstrated. First, experiments at pilot plant scale were carried out to check that the process can be extrapolated to larger scales. With the goal of scaling-up the process from laboratory scale to pilot plant, geometric similarity criteria were applied together with dynamic similarity for laminar flow in agitated tank reactors. Hence, a pilot plant installation was designed with geometrically similar equipment to those used for lab scale, obtaining analogous results in terms of recovered polyol properties. Then, the basic design of a split-phase glycolysis industrial plant with a capacity for treating 270 Tm per year of flexible PU foams scraps was proposed. Finally, the economic feasibility of such recycling process was confirmed because of the obtention of a Net Present Value (NPV) of 1,464,555€, with an Internal Rate of Return (IRR) of 27.99%, and a payback time between 4 and 5 years.

Chemical recycling of crosslinked poly(methyl methacrylate) and characterization of polymers produced with the recycled monomer

Abatract The chemical recycling of crosslinked poly(methyl methacrylate) wastes, PMMA, used as dental resins, was investigated for recovery and polymerization of the methyl methacrylate monomer, MMA. At temperatures of 400 °C in laboratory and pilot plant installations, PMMA could be depolymerized by pyrolysis to produce more than 90 wt% of liquid, containing more than 98 wt% of MMA. Gas chromatography (GC) and coupled gas chromatography – mass spectrometry (GC–MS) analyses were carried out to characterize the obtained liquid fraction. PMMA powders produced with different quantities of recycled MMA were prepared, after purification of the liquid through distillation, leading to polymer resins with properties that were similar to the ones obtained with virgin commercial MMA, as characterized by particle size, Fourier transform infrared (FT-IR), gel permeation chromatograph (GPC) and scanning electron microscopy (SEM) analyses.

Model Predictive Control in the Multi-Megawatt Range

This paper presents an application of model predictive control to a variable-speed drive system operating in the multi-megawatt range. The variable-speed drive system comprises a synchronous machine fed by a line-commutated rectifier and a load-commutated inverter. The control task is to regulate the dc-link current, and hence the machine torque, to ensure the machine speed follows a given reference. The proposed control approach is model predictive control, where both the rectifier- and inverter-firing angles are considered as control inputs. The nonlinear model predictive torque controller has been implemented on an embedded system and applied in an industrial-scale pilot plant installation. The experiments show the successful operation of model predictive control on a plant with more than 48 MW power.

Modeling study of polychlorinated dibenzo-p-dioxins and dibenzofurans behavior in flue gases under electron beam irradiation

The efficiency of the electron beam treatment of industrial flue gases for the removal of sulfur and nitrogen oxides was investigated as applied to polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) using methods of mathematical modeling. The proposed kinetic model of the process includes mechanism of PCDD/Fs decomposition caused by their interaction with OH radicals generated in the flue gases under the electron beam (EB) irradiation as well as PCDD/Fs formation from unburned aromatic compounds. The model allows to predict the main features of the process, which are observed in pilot plant installations, as well as to evaluate the process efficiency. The results of calculations are compared with the available experimental data.

Removal of Oocystis algae from freshwater by means of tannin-based coagulant

The tannin-based coagulant agent Acquapol C1 was tested for algae removal. This coagulant can be used in drinking water treatment and consists of a chemically modified tannin extract from Acacia mearnsii. Low coagulant doses reached high algae removal percentage, and operational conditions of neutral pH and room temperature allow up 80 % algae removal with 5 mg L−1 of coagulant. If compared with other natural or inorganic coagulants, Acquapol C1 is more efficient than aluminum sulfate, a classical metal salt for water clarification. Experiments also were carried out in a pilot plant installation which gives a similar efficiency as the discontinuous jar-test experiments for algae removal.

Kinetic Mechanisms of Electron-Beam Induced Polycyclic Aromatic Hydrocarbons Transformation in Flue Gases

The effect of non-thermal plasma generated by electron-beam on the behavior of polycyclic aromatic hydrocarbons (PAHs) in industrial flue gases was investigated using methods of mathematical modeling. The proposed kinetic model of the process includes mechanism of PAHs conversion caused by their interaction with OH-radicals, ion-molecular mechanism of PAHs decomposition, and ion-molecular mechanism of higher-ringed PAHs formation. The model allows to predict the main features of the process, which are observed in pilot plant installations, and to give quantitative estimations of the process efficiency. The results of calculations are compared with the available experimental data.

Pilot Plant Studies on Nox Removal Via No Ozonation and Absorption

Abstract The results of experimental investigations on the removal of NOx from gases applying ozone as the oxidizing agent and the absorption of higher nitrogen oxides in the sodium hydroxide solutions are presented. The experiment was conducted using a pilot plant installation with the air flow rate 200 m3/h, being a prototype of a boiler flue gas duct and a FGD scrubber. It was shown that in the range of [NOref] = 50 ÷ 250 ppm the mechanism of NO ozonation depends on the molar ratio X = O3/NOref: for X ≤ 1.0 oxidation of NO to NO2 predominates and NO2 is poorly absorbed, for X >> 1.0 NO2 undergoes further oxidation to N2O5, which is efficiently absorbed in the scrubber. The stoichiometric molar ratio of complete conversion of NO into N2O5 is X = 1.5, in these studies to reach the effectiveness η ≥ 90% the molar ratio X was much higher (2.75).

Practical experience of backwashing with RO permeate for UF fouling control treating surface water at low temperatures

In an ultrafiltration (UF) pilot plant installation, the efficiency of backwashing with low conductivity water has been investigated. Fresh surface water was used as feed water and no inline coagulation or other pretreatment was used. Two types of backwash water were compared: UF permeate and reverse osmosis (RO) permeate. The pilot study was conducted at low temperatures (6.5–11°C). Results show that backwash with RO permeate improved membrane fouling control efficiency. The optimization of the operational condition was 60-min filtration at a flux of 55Lm−2h−1 and 30-s backwashing at a flux of 250Lm−2h−1, with a 93% recovery. Low temperatures (6.5–11°C) accelerated the irreversible fouling, everyday-enhanced chemical backwash (ECB) (20-min soaking) was necessary and proved effective to keep a stable and extended operation. These findings indicate that it is possible to apply backwashing with RO permeate on the practical operation of UF plants for fouling control, treating surface water at low temperatures.

SEWGS Technology is Now Ready for Scale-up!

In the FP7 project CAESAR, Air Products, BP, ECN, SINTEF and Politecnico di Milano worked together in the further development of the SEWGS process with the objective to reduce the energy penalty and the costs per ton of CO2 avoided to less than €25 through optimization of sorbent materials, reactor and process design and smart integration of the SEWGS unit in a combined cycle power plant. The most promising applications for the SEWGS technology are IGCC power plants and in combined cycles power plants fuelled with blast furnace top gas.Extensive sorbent development work resulted in a new sorbent called ALKASORB+ with a high capacity resulting in cost of CO2 avoided for the IGCC application of €23. This is a reduction of almost 40% compared to the Selexol capture case. Since ALKASORB+ requires much less steam in the regeneration, the specific primary energy consumption is reduced to 44% below the specific energy consumption for the Selexol (2.08 versus 3.71 MJLHV/kgCO2).From a technical point of view SEWGS is ready to move to the next development level, which is a pilot plant installation with a capacity of 35 ton CO2 per day. This is over 500 times larger than the current ECN's multi column SEWGS installation, but still 50 times smaller than an envisaged commercial scale installation. The pilot plant will prove the technology under field conditions and at a sufficiently large scale to enable further up-scaling, delivering both the basic design and investment costs of a full scale SEWGS demonstration plant.

Pilot-scale studies on NOx removal from flue gas via NO ozonation and absorption into NaOH solution

Abstract The paper presents results of experimental studies on removal of NOx from flue gas via NO ozonation and wet scrubbing of products of NO oxidation in NaOH solutions. The experiment was conducted in a pilot plant installation supplied with flue gas from a coal-fired boiler at the flow rate 200 m3/h. The initial mole fraction of NOx,ref in flue gas was approx. 220 ppm, the molar ratio X = O3/NOref varied between 0 and 2.5. Ozone (O3 content 1÷5% in oxygen) was injected into the flue gas channel before the wet scrubber. The effect of the mole ratio X, the NaOH concentration in the absorbent, the liquid-to-gas ratio (L/G) and the initial NOx concentration on the efficiency of NOx removal was examined. Two domains of the molar ratio X were distinguished in which denitrification was governed by different mechanisms: for X ≤ 1.0 oxidation of NO to NO2 predominates with slow absorption of NO2, for X >> 1.0 NO2 undergoes further oxidation to higher oxides being efficiently absorbed in the scrubber. At the stoichiometric conditions (X = 1) the effectiveness of NO oxidation was better than 90%. However, the effectiveness of NOx removal reached only 25%. When ozonation was intensified (X ≥ 2.25) about 95% of NOx was removed from flue gas. The concentration of sodium hydroxide in the aqueous solution and the liquid-to-gas ratio in the absorber had little effect on the effectiveness of NOx removal for X > 2.

Determining convective heat transfer coefficient during sterilisation of canned evaporated whole milk

The effect of retort temperature, rotation speed, headspace and radius of rotation on mean convective heat transfer coefficient during sterilisation of canned evaporated whole milk was studied. The mean total solids content of evaporated milk obtained in a pilot plant installation was 25.25 g/100 g. Processing variables used ranged as follows: retort temperature: 117–123 °C; speed of rotation: 10–20 rpm; headspace: 4–12 mm; radius of rotation: 3.5–16.5 cm. The model developed for heat transfer coefficient was adequate, showing no significant lack of fit and satisfactory coefficient of determination. Retort temperature, speed of rotation, headspace and radius of rotation have a significant effect. Dimensional correlations were developed for convective heat transfer coefficient, in terms of Nusselt number as a function of Reynolds number, Prandtl number and relative headspace; the best agreement was obtained using the diameter of rotation as the characteristic dimension.

Removal of Carmine Indigo Dye with Moringa oleifera Seed Extract

Moringa oleifera has been tested as an active agent in removing various types of anionic dyes. Specially, removal of an indigoid dye, Carmine Indigo, has been tested. The fast kinetics of coagulant action and the high potential of this coagulant agent to treat wastewater from dyestuff has been revealed. Moringa oleifera is fully working in coagulation and flocculation process, and it achieves an average level of removal up to 80%. The pH does not affect the coagulant process, and temperature has a negative influence. By increasing initial dye concentration, lower dye percentage removal is achieved and higher q is presented. Coagulation and flocculation processes can be estimated by the Langmuir and Freundlich models, but the first one gives a better explanation of the coagulation and adsorption behavior (r2 equal to 0.97). Carmine Indigo removal presents an optimum q capacity at 343 mg·L−1 and 11.2 °C. Pilot plant installation gives a similar efficiency for dye removal.

Enhancing performance of rectification columns for ethanolamine manufacturing

A problem is considered of enhancing performance of pilot plant installation for manufacturing ethanolamine by replacement of modern packed towers for old type rectification columns. The modernization result is increase in productivity and product quality, and energy saving.

Monitoring biodiesel production (transesterification) using in situ viscometer

Biodiesel, an alternative diesel fuel made from renewable sources, is produced by the transesterification of oil or fat with alcohol. In order to monitor the progress of this reaction, in situ viscosity measurements were taken using an acoustic wave solid state viscometer. This novel concept is reported from the proof-of-concept stage to a pilot plant installation. The viscometer was able to monitor the reaction until the end-point was reached, and could therefore be adapted in the future for process control in a batch transesterification reactor for biodiesel production.

Pilot plant testing of a new solar desalination process by a multiple-effect-humidification technique

After concluding a detailed research on separate pieces of equipment needed for the new desalination process, Phase 1 pilot plant installation for testing and optimizing the whole process was constructed and installed in INRST-Tunisia. The aim of this investigation is to experimentally test the new solar desalination process working with an air multiple-effect humidification–dehumidification technique. A pilot plant unit was designed and constructed to carry out this test investigation. The main parts of the process consist of an air collector field, spray humidifiers and a dehumidifier and heat recovery system. The process flow sheet has undergone several changes: the number of heating–humidifying stages has been lowered from 18 to 15 stages, then to 9 stages, then to 4 stages. The present study concerns Phase 1 installation setup involving two heating–humidifying stages, heat recovery and condensation system and auxiliary equipment (blower, pumps, reservoirs, etc.). Phase 2 installation setup will include the remaining equipment to complete a 4-stage plant. Phase 1 SOLDES pilot plant had been tested during a six-month period (from March to August 2003). The distilled water production had been optimized. Data relative to the operating parameters of each single component of the process (collectors' outlet temperatures, humidifier parameters, recuperated water temperature) are presented. Also, the daily and monthly fresh water production of the pilot plant is obtained. The fresh water production had reached an average value of 355 kg/d during the month of August 2003.

A16: Web-based control and monitoring of the experimental pilot-plant installations

In this paper, a methodology of a web-based control and monitoring of the experimental pilot-plant installations is presented. The presented methodology provides scientists and engineers with an access to the experimental pilot-plants at the Institute of Automatic Control, and enables experiments to be carried out via Internet. A LabVIEW-based software is presented that allows distant programming of the experiments (both by specifying sequences of commands to be carried out, and by sending and executing dynamically loaded plugins used for realizing continuous control algorithms). As an example, control of the wastewater treatment experimental pilot-plant is presented.

Séparation électrostatique: complément des procédés mécaniques de recyclage des déchets industriels

The electrostatic separation of metals and insulators from granular mixtures is more and more widely used in the waste recycling industry. The aim of this paper is double: (1) present the procedure that is employed for the development of new applications, by using a pilot-plant installation, designed and built by the authors; (2) illustrate the usefulness of electrostatic separation as a complement to mechanical techniques employed for industrial waste processing. The study was carried out on samples furnished by an Algerian company specialised in the recycling of electric cable wastes. The limit values of the two control variables of the process (roll-speed and high-voltage level) were established after a set of preliminary experiments. Pilot-plant tests confirmed the efficiency of the electrostatic separation for two copper-plastic granular mixtures.