Pilot Plant Trials Research Articles

The positive effects of bed material coating on tar reduction in a dual fluidized bed gasifier

The utilization of biomass for the substitution of fossil fuels to reduce greenhouse gas emissions in biomass steam gasification plants is a promising technology for the production of electricity, heat, and fuels for transportation. Experience from industrial scale dual fluidized bed steam gasification plants showed a modification of the bed material due to the interaction of the bed material (olivine) with biomass ash components and additives. In this paper the influence of bed material modification on the gasification properties of used olivine from an industrial scale plant in Güssing is compared with the case of fresh olivine. The trials were carried out under similar conditions in a pilot plant at the Vienna University of Technology. The pilot plant trials showed an increase in hydrogen and carbon dioxide in the product gas with the used bed material while the content of carbon monoxide in the product gas decreased. The exothermal water–gas shift reaction is enhanced by the used bed material, resulting in a lower energy demand for the gasification. Tar content was decreased by around 80% for tars detected by gas chromatography–mass spectrometry (GCMS) and the composition of the tar showed less components during the trial with used bed material.The results obtained with the used bed material at the 100kW pilot plant are in good agreement with those for the 8MW industrial plant in Güssing, confirming good scale-up properties from the 100kW plant to industrial scale plants.

Purification of molybdenum trioxide calcine by selective leaching of copper with HCl–NH 4Cl

The leaching of Mo, Cu and Fe from MoO 3 calcines (59–61% Mo) containing 1–2% Cu, 1–2% Fe and other impurities produced from roasting molybdenite (MoS 2) concentrate was examined using water and a series of chloride lixiviants, including NH 4Cl (0.6 M), HCl (0.115–1.40 M) and a mixture of HCl (0.70 M) + NH 4Cl (0.1–0.93 M) at a solid/leachant (w/v) ratio of 1:1 and within the temperature range 25–70 °C. Stabcal modelling showed that there are many compounds formed from Cu, Fe and Mo co-exist in the solution. Optimisation studies show that HCl solutions of concentrations ≥ 0.35 M are capable of dissolving > 80% of Cu within 1 h. The addition of NH 4Cl (0.30–0.93 M) to 0.7 MHCl reduces the dissolution of Mo to < 0.5%, due to the formation of a precipitate containing mainly NH 3(MoO 3) 3, as confirmed by X-ray diffraction. A mixture of 0.7 M HCl and 0.6 M NH 4Cl at ambient temperatures removes Cu to < 0.5% within 2 h, as required for the production of Fe–Mo alloys at Kwangyang Ferro Alloys Co. (Korea). Although not required, Fe was removed to < 0.6% whereas most other metal impurities were removed to < 0.1%. Pilot plant trials over 7 campaigns, each treating 2.0–2.2 tonnes of MoO 3 calcine containing 2.1% Cu using 1.44 M NH 4Cl and 0.97 M HCl at an ambient temperature yielded final products containing 0.22% Cu as required. Mass balance calculations (closure to 96–99%) of the pilot plant trials confirm that the Mo loss during leaching is around 0.5%.

Depolymerisation of oligolactic acid: Simulation and pilot plant trial

The oligolactic acid thermodestruction process was studied using the pilot plant. The process was described by the system of differential rate equations. The model satisfactorily simulating the pyrolysis of oligolactic acid was built and reactions rate constants were determined. It was shown that to obtain a high purity product higher molecular weight feedstock should be used. That will result in a longer process times. The main impurities are low molecular weight homologues with polymerisation degree 1–3. No significant changes in a molecular mass and molecular mass distribution occur during the pyrolysis. The only changes that have place occur at the initial steps and are due to stripping of light components and, possibly, depolymerisation. When the oligomer molecular mass M n reaches a certain threshold value no further changes occur. Pilot plant trials showed the good agreement of simulation and experiment.

Results from trialling aqueous NH 3 based post-combustion capture in a pilot plant at Munmorah power station: Absorption

Australia's Commonwealth Scientific and Industrial Research Organization (CSIRO) and Delta Electricity have developed, commissioned and operated an A$7 million aqueous NH 3 based post-combustion capture (PCC) pilot plant at the Munmorah black coal fired power station in Australia. The results from the pilot plant trials will be used to address the gap in know-how on application of aqueous NH 3 for post-combustion capture of CO 2 and other pollutants in the flue gas and explore the potential of the NH 3 process for application in the Australia power sector. This paper is one of a series of publications to report and discuss the experimental results obtained from the pilot plant trials and primarily focuses on the absorption section. The pilot plant trials have confirmed the technical feasibility of the NH 3 based capture process. CO 2 removal efficiency of more than 85% can be achieved even with low NH 3 content of up to 6 wt%. The NH 3 process is effective for SO 2 but not for NO in the flue gas. More than 95% of SO 2 in the flue gas is removed in the pre-treatment column using NH 3. The mass transfer coefficients for CO 2 in the absorber as functions of CO 2 loading and NH 3 concentration have been obtained based on pilot plant data.

Application of UV disinfection in municipal wastewater treatment plants for agricultural use of reclaimed wastewater in Turkey

In this study, the UV disinfection efficiency based on wastewater quality parameters such as suspended solids, UV transmittance, and initial coliform concentrations (total and fecal coliform) was examined and the appropriate UV-C doses for providing the fecal and total coliform values declared at different regulations and standards for agricultural reuse were investigated. The study was carried out in a UV pilot plant installed at Pasakoy advanced biological wastewater treatment plant, located in Istanbul. The pilot plant was an open-channel system with a capacity of 100 m3/h. The pilot plant also contained a pressurized sand filter. The effluent taken from the outlet of final clarifiers of Pasakoy WWTP was used in the pilot plant trials. Experiments were conducted with filtered and unfiltered wastewater at various UV-C doses between 20 and 150 mWs/cm2. The results of the study indicated that the required UV-C dose to achieve a Class 1 water quality according to Turkish Regulations is 140 mWs/cm2. UV tran...

Results from trialling aqueous ammonia based post combustion capture in a pilot plant at Munmorah

Abstract CSIRO and Delta Electricity have developed, commissioned and operated an aqueous ammonia based post combustion capture (PCC) pilot plant at the Munmorah black coal fired power station. The results from the pilot plant trials will be used to address the gap in know-how on application of aqueous ammonia for post combustion capture of CO 2 and other pollutants in the flue gas and explore the potential of the aqueous ammonia based capture process for application in the Australia power sector. This paper reports and discusses part of experimental results obtained from the pilot plant trials.

Modified jet flotation in oil (petroleum) emulsion/water separations

This work presents results of a rapid emulsified oil (petroleum) removal from water by flocculation followed by flotation in a modified jet (Jameson) cell (MJC). The modification is such that the downcomer was sealed at the bottom (by a concentric blind-end tube) to allow floated particles to enter immediately into the frothy phase after the capture of the oily flocs by the bubbles. Also, a packed bed (crowder) was placed at the upper part of the concentric tube to stabilize the froth and facilitate the rise of the oil floc/bubble aggregates. The work was divided into two parts: a detailed laboratory study (1.3 m 3/h) and a pilot plant trial in an offshore platform. Parameters studied were flocculation (type and concentration of polymer), oil concentration, oil droplets size distribution and flotation cell design. Results of laboratory studies showed mean separation efficiencies of the order of 80% when used as a conventional jet cell (CJC) with feed emulsions (droplets size of about 20 μm) ranged between 100 and 400 mg/L petroleum concentration. The oil removal increased up to 85% in the MJC. These studies allowed optimizing the design and process parameters: chemical, physico-chemical and operating. A MJC (5 m 3/h) was then projected, built and installed in an offshore platform, after the oil extraction–production point. At optimal conditions, in a single flotation stage, discharges varied between 20 and 30 mg/L oil concentration or 81% removal at 24.7 m 3/h m 2 loading capacity. Because this jet cell operates with a high air hold-up, it presented a very good efficiency (capture of oil droplets by bubbles) at low residence time (high-rate separation) and showed to be simple, compact and easy to operate. It is believed that the MJC has a great potential for treating polluted oily high flow wastewaters, at high separation rate. Results and mechanisms involved are discussed in terms of interfacial phenomena and design factors.

Flotation data for the design of process plants Part 1 – testing and design procedures

This paper discusses the methods used in the design of flotation plants, including benchscale batch and locked cycle tests and pilot plant trials. The methods used to establish appropriate flotation circuits as well as the interpretation of the test work data are also discussed in this paper. Careful and appropriate sample selection must be followed by equally carefully designed and executed flotation test work if a successful outcome is to be achieved. These steps are detailed and the correct use of each type of test and the information which can be obtained is described. Practical design considerations such as flotation time, type, number and size of flotation cells, and the means of froth transport are all important and appropriate test work can guide decisions on all these factors.

Flotation data for the design of process plants Part 2 – case studies

The Cadia Hill Gold Mine and the Hellyer copper, zinc and lead plant present different problems with widely different target grind sizes, liberation characteristics. The contrast is between Hellyer's sequential flotation circuit versus Cadia's 'simple' copper–gold flotation circuit. The common theme is that pyrite forms the principal floatable concentrate diluent. Hellyer ore contains finely disseminated chalcopyrite, sphalerite, galena and tetrahedrite. The flotation plant design was based on extensive benchscale test work (including locked cycle tests) on drill core and many months of operation of a 30 t h−1 'pilot plant' using the modified Cleveland Tin Mine processing plant. The Cadia concentrator was designed based on an extensive benchscale variability test work programme. Data from approximately a dozen locked cycle tests conducted on drill core and 2 weeks of continuous pilot plant trials of samples obtained from an adit into the orebody were used as the basis of design. The orebody is a low grade monzonite porphyry with disseminated chalcopyrite/bornite/pyrite (0·17%Cu, 0·73 g t−1 Au). Methods used to establish the appropriated flotation circuits for the treatment of the Hellyer and Cadia ores, as well as the interpretation of the test work data for these particular operations, are discussed. The predicted versus actual operational plant is reviewed and the comparison was found to be satisfactory.

Operating boundaries of full-scale advanced water reuse treatment plants: many lessons learned from pilot plant experience

Three Advanced Water Treatment Plants (AWTP) have recently been built in South East Queensland as part of the Western Corridor Recycled Water Project (WCRWP) producing Purified Recycled Water from secondary treated waste water for the purpose of indirect potable reuse. At Luggage Point, a demonstration plant was primarily operated by the design team for design verification. The investigation program was then extended so that the operating team could investigate possible process optimisation, and operation flexibility. Extending the demonstration plant investigation program enabled monitoring of the long term performance of the microfiltration and reverse osmosis membranes, which did not appear to foul even after more than a year of operation. The investigation primarily identified several ways to optimise the process. It highlighted areas of risk for treated water quality, such as total nitrogen. Ample and rapid swings of salinity from 850 to 3,000 mg/l-TDS were predicted to affect the RO process day-to-day operation and monitoring. Most of the setpoints used for monitoring under HACCP were determined during the pilot plant trials.

Pilot plant trials: management of membrane concentrate

In surface water nanofiltration (NF) for drinking water production, 15 to 25% of the feed is rejected by the membranes. Two complementary approaches are investigated in order to manage concentrates. On one hand, an additional NF stage allows an increase in the yield of drinking water production from 85 to 94%. Thirty-days filtration cycles are achieved. Conductivity, natural organic matter (NOM) and micropollutant contents of permeate fully satisfy drinking water standards. On the other hand removal of phosphonates, micropollutants and NOM is investigated in order to treat the concentrate before disposal. Phosphorus is removed by adsorption on pre-treatment sludge: removal reaches 82% with 100 ppm of suspended solids. To eliminate pesticides and NOM, adsorption on granular activated carbon (GAC) is studied with pilot scale fixed bed columns. Within 20 minutes contact time, selected pesticides are completely eliminated. NOM removal is approximately 30% with wood based GAC.

Separation of Cobalt and Zinc from Manganese, Magnesium, and Calcium using a Synergistic Solvent Extraction System Consisting of Versatic 10 and LIX 63

The Boleo leach solution contains large amounts of manganese (45 g/L), magnesium (25 g/L) and small amounts of cobalt (0.2 g/L) and zinc (1 g/L) in sea water. Due to the high manganese concentration, it is very difficult to separate cobalt and zinc from manganese, magnesium, and calcium using conventional solvent-extraction processes, which has led to the development of a synergistic solvent extraction (SSX) system consisting of Versatic 10 and LIX®63. By adding 0.4 M LIX 63 to 0.5 M Versatic 10, large synergistic shifts were obtained for cobalt (max. ΔpH50 4.24) and zinc (max. ΔpH50 1.62). After a single contact at pH 4.5, the extraction of cobalt was almost complete and that of zinc 80%. The extraction of manganese was 1.55%, and almost no magnesium and calcium were extracted, indicating excellent separation of cobalt and good separation of zinc from manganese, magnesium, and calcium. The SSX system was further optimized to reduce the co-extraction of manganese with the synthetic Boleo demonstration plant solution. It was found that with 0.33 M Versatic 10 and 0.30 M LIX 63, the SSX system composition approached optimum. After a single contact at pH 5.5, the extractions of cobalt and zinc were 93% and 70%, respectively, while the manganese concentration in the loaded organic solution was only 0.28 g/L. The extraction and stripping kinetics of cobalt and zinc were rapid. The SSX system was tested in two integrated pilot-plant trials with excellent results. Baja Mining has planned to implement the SSX circuit in their future Boleo plant.

Surface water and wastewater treatment using a new tannin-based coagulant. Pilot plant trials

A new tannin-based coagulant-flocculant ( Tanfloc) was tested for water treatment at a pilot plant level. Four types of water sample were treated: surface water (collected from a river), and municipal, textile industry (simulated by a 100 mg L −1 aqueous solution of an acid dye), and laundry (simulated by a 50 mg L −1 aqueous solution of an anionic surfactant) wastewaters. The pilot plant process consisted of coagulation, sedimentation, and filtration. The experiments were carried out with an average coagulant dosage of 92.2 mg L −1 (except in the case of the surface water for which the dosage was 2 mg L −1). The efficacy of the water purification was notable in every case: total turbidity removal in the surface water and municipal wastewater, about 95% dye removal in the case of the textile industry wastewater, and about 80% surfactant removal in the laundry wastewater. Filtration improved the removal of suspended solids, both flocs and turbidity, and slightly improved the process as a whole. The efficiency of Tanfloc in these pilot studies was similar to or even better than that obtained in batch trials.

A hybrid flotation–gravity circuit for improved metal recovery

The performance of a novel hybrid flotation–gravity concentration circuit was evaluated in which a Knelson Continuous Variable Discharge (CVD) separator was used as a scavenger for flotation tailings. Flotation tailings from the Eskay Creek Gold Mine were used for the study. Batch and pilot scale laboratory tests and plant trials were performed. Results of the batch and pilot tests showed that a product with a small yield (<5%), a high upgrade ratio and significant Au (sulphide mineral) recovery could be achieved. Plant trials confirmed the laboratory test results and hybrid flotation–gravity circuit in which CVD scavenging was followed by a regrinding-flotation process, could increase overall plant gold recoveries. In view of the results, there is also potential for improvements in metal recoveries for other sulphide mineral flotation systems. The paper describes how the results influence the selection of the target grind size and thereby impact grinding energy requirements, plant processing rate and could lead to further improvements in metal recovery by reducing flotation losses at the ultrafine particle size range.

Advances in biohydrogen production processes: An approach towards commercialization

Biological H 2 production has an edge over its chemical counterpart mainly because it is environmentally benign. Despite having simpler technology, higher evolution rate of H 2 and the wide spectrum of substrate utilization, the major deterrent of anaerobic dark fermentation process stems from its lower achievable yields. Theoretically, the maximum H 2 yield is 4 mol H 2 /mol glucose when glucose is completely metabolized to acetate or acetone in the anaerobic process. But it is somewhat difficult to achieve the complete degradation of glucose to carbon dioxide and H 2 through anaerobic dark fermentation. Moreover, this yield appears too low to be economically viable as an alternative to the existing chemical or electrochemical processes of hydrogen generation. Intensive research studies have already been carried out on the advancement of these processes, such as the development of genetically modified microorganism, improvement of the reactor designs, use of different solid matrices for the immobilization of whole cells, development of two-stage processes, and higher H 2 production rates. Maximum H 2 yield is found to be 5.1 mol H 2 /mol glucose. However, major bottlenecks for the commercialization of these processes are lower H 2 yield and rate of H 2 production. Competent microbial cultures are required to handle waste materials efficiently, which are usually complex in nature. This will serve dual purposes: clean energy generation and bioremediation. Scale-up studies on fermentative H 2 production processes have been done successfully. Pilot plant trials of the photo-fermentation processes require more attention. Use of cheaper raw materials and efficient biological H 2 production processes will surely make them more competitive with the conventional H 2 generation processes in near future.

Advances in biological hydrogen production processes

Biological hydrogen production processes offer a technique through which renewable energy sources like biomass can be utilized for the generation of the cleanest energy carrier for the use of mankind. Hydrogen intensive research work has already been carried out on the advancement of these processes, such as the development of genetically modified microorganism, metabolic engineering, improvement of the reactor designs, use of different solid matrices for the immobilization of whole cells, biochemical assisted bioreactor, development of two-stage processes, etc. for higher H 2-production rates. Maximum H 2 yield is found to be 7.1 mol H 2/mol glucose. However, major bottlenecks for the commercialization of these processes are lower H 2 yield and rate of H 2 production. Suitable microbial cultures are required to handle waste materials efficiently, which are usually complex in nature. This will serve dual purposes: clean energy generation and bioremediation. Scale-up studies on fermentative H 2-production processes have been done successfully. Pilot plant trials of the photo-fermentation processes require more attention. Use of cheaper raw materials and efficient biological hydrogen production processes will surely make them more competitive with the conventional H 2 generation processes in near future.

Effects of ion exchange resin pre-treatment on GAC adsorption

In Italian drinking water treatment plants (DWTP), the problem of chlorination by-products control is very important as the Italian drinking water regulations (Dlgs. 31/2001, as enactment of the CEU directive 98/83) set very strict limits for these compounds. A possible strategy for controlling the concentrations of DBPs (disinfection by-products) is the application of treatment processes able to reduce the concentration of dissolved organic matter, the main precursor of DBPs, before the dosage of chlorine-based disinfectants. Recently, ion exchange resins for the removal of dissolved organics have shown several applications in drinking water treatment. In this experimental study, the treatment with ion exchange resins MIEX®DOC and the treatment with GAC (granular activated carbon) were evaluated for the removal of dissolved organics. Moreover, the effects of MIEX® pre-treatment on the subsequent GAC filtration phase were evaluated, with particular attention to the effects on the life-time of the GAC filter. The GAC filter operation was simulated by rapid small scale column tests (RSSCT), which allow the evaluation of the GAC breakthrough curve in a shorter time with respect to a full plant and pilot plant trials. On the basis of the experimental results, the ion exchange process was very efficient in dissolved organics removal (60–70% UV254 removal). Moreover, the results indicated that the application of ion exchange resins as pre-treatment in a conventional drinking water treatment train could increase the filter life-time in the subsequent GAC adsorption phase (about 200%) resulting in potentially important cost benefits for the overall treatment process.

The Tecnored ironmaking process Part 1 – Competitiveness and pilot development work

The Tecnored emergent iron reduction technology has the potential to provide significant operating cost to hot metal advantages over traditional blast furnace and DRI/HBI technologies. Capital cost and scale efficiency are also projected to be lower. A technical and economic overview of the Tecnored process is given, together with final results from pilot plant trials.

Extraction of native collagen from limed bovine split wastes through improved pretreatment methods

AbstractBACKGROUND: The large amount of limed bovine split wastes discharged by the leather industry has raised concerns regarding their environmental effect. The objective of this work was to perform pilot plant trials to extract high‐value native collagen from these wastes through improved pretreatment methods.RESULTS: EDTA‐ and HCl‐pretreatment gave similar removal percentages of inorganic substances. Owing to the open structure of fibers, the collagen yield of HCl‐pretreated splits (HPS) (41.31%) was higher than that of EDTA‐pretreated splits (EPS) (10.42%). Furthermore, HCl‐pretreated split collagen (HPC) had a more acidic isoelectric point, lower content of primary amino groups, larger Z‐average particle size and higher relative viscosity than EDTA‐pretreated split collagen (EPC). Electrophoretic analysis and circular dichroism spectra revealed the maintenance of polypeptide and triple helix conformation, respectively. In addition, the transition temperatures of EPC (34.7 °C) and HPC (34.6 °C) detected by differential scanning calorimetry (DSC) were close to that of commercial collagen from calfskin (CCC) (35.7 °C).CONCLUSION: A process of native collagen extraction from limed bovine split wastes was proposed. While both EPC and HPC represented similar physicochemical properties to those of CCC, the collagen yield of HPS was much higher than that of EPS. Copyright © 2008 Society of Chemical Industry

Fluidized Bed Dryers — Recent Advances

Although industrial fluidized bed dryers have been used successfully for the drying of wet solid particles for many years, the development of industrial fluidized bed dryers for any particular application is fraught with difficulties such as scaling-up, poor fluidization and non-uniform product quality. Scaling-up is the major problem and there are very few good, reliable theoretical models that can replace the expensive laboratory work and pilot-plant trials. This problem is mainly due to the different behavior of bubbles and mixing regimes in fluidized bed dryers of different size. Simple transformation of laboratory batch drying data to continuous back-mixed dryers using the residence time distribution of the solids is insufficient to account for the complex flow and heat and mass transfer phenomena occurring in the bed. Although time scaling using temperature driving forces and solids mass flux for the same change in moisture content in the batch and continuous dryers has been successful in predicting moisture content profiles in the continuous dryer at the constant rate period, it does not take into account solid mixing. Two-phase Davidson–Harrison models have been used in modeling of the continuous back-mixed dryer with various degrees of success. On the other hand, the three-phase Kunii–Levenspiel model is seldom used in modeling fluidized bed dryers because it is too complex to handle. A combination of multi-phase models and residence time distribution could improve predicting power for back-mixed dryers because this combination takes into account both the bubbles and solid mixing phenomena. Incremental models were widely used to model continuous plug flow fluidized bed dryers, but the cross-flow of drying medium has not been sufficiently modeled except by the author. In some incremental models, axial dispersion is modeled using the Peclet number, Pe. A combination of an incremental model with an axial dispersion and cross-flow model of drying medium would improve predicting power. Poor fluidization of Geldart group C particles could be improved by the assistance of external means such as vibration, agitation, rotation and centrifugation. Both vibrated and agitated fluidized bed dryers have been successfully used in industry, but rotating or centrifugal fluidized bed dryers are still not available for industrial use.