The role of metal ions in selective and sustainable processes

Sustainability and recycling are core values in today’s industrial operations. New materials, products and processes need to be designed in such a way as to consume fewer of the diminishing resources we have available and to put as little strain on the environment as possible. An integral part of this is cleaning and recycling. New processes are to be designed to improve the efficiency in this aspect. Wastewater, including municipal wastewaters, is treated in several steps including chemical and mechanical cleaning of waters. Well-cleaned water can be recycled and reused. Clean water for everyone is one of the greatest challenges we are facing today. Ferric sulphate, made by oxidation from ferrous sulphate, is used in water purification. The oxidation of ferrous sulphate, FeSO4, to ferric sulphate in acidic aqueous solutions of H2SO4 over finely dispersed active carbon particles was studied in a vigorously stirred batch reactor. Molecular oxygen was used as the oxidation agent and several catalysts were screened: active carbon, active carbon impregnated with Pt, Rh, Pd and Ru. Both active carbon and noble metal-active carbon catalysts enhanced the oxidation rate considerably. The order of the noble metals according to the effect was: Pt >> Rh > Pd, Ru. By the use of catalysts, the production capacities of existing oxidation units can be considerably increased. Good coagulants have a high charge on a long polymer chain effectively capturing dirty particles of the opposite charge. Analysis of the reaction product indicated that it is possible to obtain polymeric iron-based products with good coagulation properties. Systematic kinetic experiments were carried out at the temperature and pressure ranges of 60B100°C and 4B10 bar, respectively. The results revealed that both non-catalytic and catalytic oxidation of Fe2+ to Fe3+ take place simultaneously. The experimental data were fitted to rate equations, which were based on a plausible reaction mechanism: adsorption of dissolved oxygen on active carbon, electron transfer from Fe2+ ions to adsorbed oxygen and formation of surface hydroxyls. A comparison of the Fe2+ concentrations predicted by the kinetic model with the experimentally observed concentrations indicated that the mechanistic rate equations were able to describe the intrinsic oxidation kinetics of Fe2+ over active carbon and active carbon-noble metal catalysts. Engineering aspects were closely considered and effort was directed to utilizing existing equipment in the production of the new coagulant. Ferrous sulphate can be catalytically oxidized to produce a novel long-chained polymeric iron-based flocculent in an easy and affordable way in existing facilities. The results can be used for modelling the reactors and for scale-up. Ferric iron (Fe3+) was successfully applied for the dissolution of sphalerite. Sphalerite contains indium, gallium and germanium, among others, and the application can promote their recovery. The understanding of the reduction process of ferric to ferrous iron can be used to develop further the understanding of the dissolution mechanisms and oxidation of ferrous sulphate. Indium, gallium and germanium face an ever-increasing demand in the electronics industry, among others. The supply is, however, very limited. The fact that most part of the material is obtained through secondary production means that real production quota depends on the primary material production. This also sets the pricing. The primary production material is in most cases zinc and aluminium. Recycling of scrap material and the utilization of industrial waste, containing indium, gallium and geranium, is a necessity without real options. As a part of this study plausible methods for the recovery of indium, gallium and germanium have been studied. The results were encouraging and provided information about the precipitation of these valuables from highly acidic solutions. Indium and gallium were separated from acidic sulphuric acid solutions by precipitation with basic sulphates such as alunite or they were precipitated as basic sulphates of their own as galliunite and indiunite. Germanium may precipitate as a basic sulphate of a mixed composition. The precipitation is rapid and the selectivity is good. When the solutions contain both indium and gallium then the results show that gallium should be separated before indium to achieve a better selectivity. Germanium was separated from highly acidic sulphuric acid solutions containing other metals as well by precipitating with tannic acid. This is a highly selective method. According to the study other commonly found metals in the solution do not affect germanium precipitation. The reduction of ferric iron to ferrous, the precipitation of indium, gallium and germanium, and the dissolution of the raw materials are strongly depending on temperature and pH. The temperature and pH effect were studied and which contributed to the understanding and design of the different process steps. Increased temperature and reduced pH improve the reduction rate. Finally, the gained understanding in the studied areas can be employed to develop better industrial processes not only on a large scale but also increasingly on a smaller scale. The small amounts of indium, gallium and germanium may favour smaller and more locally bound recovery.

Modified atmosphere efficiency in the quality maintenance of Eva apples

Modified atmosphere is a method of food preservation that provides increased lifetime, decreases deterioration losses, and facilitates marketing. The objective of this study was to evaluate the efficiency of different plastic films in modifying the atmosphere around Eva apples to assure quality maintenance during postharvest storage. The fruits were cleaned and separated into three treatment groups: polypropylene, low density polyethylene, and high density polyethylene packing with a total of 5 fruits per package for each evaluation period. A group of control apples was not submitted to atmospheric modification. After the treatment, all fruits were stored at 0.5±0.5°C (cold storage) for up to 225 days. The analyses were performed at 45, 135, and 225 days after cold storage. Respiration, ethylene production, firmness, mass loss, total pectin, soluble pectin, soluble solids, total acidity, and epidermis background color of each treatment group were evaluated. The high density polyethylene film treatment did not show a decrease in ethylene production during storage and allowed the fruits to maintain a greater firmness and smaller percentage of mass loss during the study period. Moreover, the storage of the Eva apple cultivar under modified atmosphere allowed the preservation of quality for up to seven months.

Uncertainty of Efficiency Measurements in Electric Drives

The two central goals of this master's thesis are to serve as a guidebook on the determination of uncertainty in efficiency measurements and to investigate sources of uncertainty in efficiency measurements in the field of electric drives by a literature review, mathematical modeling and experimental means. The influence of individual sources of uncertainty on the total instrumental uncertainty is investigated with the help of mathematical models derived for a balance and a direct air cooled calorimeter. The losses of a frequency converter and an induction motor are measured with the input-output method and a balance calorimeter at 50 and 100 % loads. A software linking features of Matlab and Excel is created to process measurement data, calculate uncertainties and to calculate and visualize results. The uncertainties are combined with both the worst case and the realistic perturbation method and distributions of uncertainty by source are shown based on experimental results. A comparison of the calculated uncertainties suggests that the balance calorimeter determines losses more accurately than the input-output method with a relative RPM uncertainty of 1.46 % compared to 3.78 - 12.74 % respectively with 95 % level of confidence at the 93 % induction motor efficiency or higher. As some principles in uncertainty analysis are open to interpretation the views and decisions of the analyst can have noticeable influence on the uncertainty in the measurement result.

Enhanced extraction of phenolic compounds from coffee industry’s residues through solid state fermentation by Penicillium purpurogenum

Abstract The use of agroindustrial residues is an economical solution to industrial biotechnology. Coffee husk and pulp are abounding residues from coffee industry which can be used as substrates in solid state fermentation process, thus allowing a liberation and increase in the phenolic compound content with high added value. By employing statistical design, initial moisture content, pH value in the medium, and the incubation temperature were evaluated, in order to increase the polyphenol content in a process of solid state fermentation by Penicillium purpurogenum. The main phenolic compounds identified through HPLC in fermented coffee residue were chlorogenic acid, caffeic acid, and rutin. Data obtained through HPLC with the radical absorbance capacity assay suggest the fermented coffee husk and pulp extracts potential as a source of phenolic acids and flavonoids. Results showed good perspectives when using P. purpurogenum strain to enhance the liberation of phenolic compounds in coffee residues.

Energy efficiency and moisture diffusivity of apple slices during convective drying

Abstract The present study aimed at investigating the influences of drying air temperature and flow rate on energy parameters and dehydration behaviour of apple slices. For this purpose, apple slices were dried in a convective dryer at air temperatures of 50, 60 and 70 °C, and air velocities of 1, 1.5 and 2 m s–1. Dehydration rate increased as the air temperature and flow rate increased from 50 to 70 °C and 1 to 2 m s–1, respectively. The effective moisture diffusivity was determined to be in the range of 6.75×10–10-1.28×10–9 m2 s–1. Results of data analysis showed that the maximum energy consumption (23.94 kW h) belonged to 50 °C and 2 m s–1 and the minimum (13.89 kW h) belonged to 70 °C and 1 m s–1 treatment. Energy efficiency values were in the range of 2.87-9.11%. Moreover, the results indicated that any increment in the air temperature increases thermal and drying efficiencies while any increment in the air flow rate decreases both of them.

Tilaus-toimitusketjun toimivuus kiinteistö- ja aluepalveluissa kaupunkikonsernin näkökulmasta

Imatralla tilaaja-tuottaja-malliin liittyvä nykyinen sopimusohjausmalli otettiin käyttöön teknisellä toimialalla marraskuussa 2014, jolloin kiinteistö- ja aluepalveluiden tuottamiseen perustettiin oma yhtiö. Tilaaminen ja tuottaminen muodostaa tilaus-toimitusketjun. Tämän työn tarkoituksena oli saada tietoa nykyisen kiinteistö- ja aluepalveluiden tilaus-toimitusketjun toimivuudesta sekä vahvuuksista ja puutteista. Työn teoriaosassa perehdyttiin strategiaprosessiin kunnissa, tilaaja-tuottaja-toimintatapaan sekä yhtiöittämiseen ja tuloksellisuuteen. Käytännön tietoa tilaus-toimitusketjusta saatiin strukturoidulla haastattelulla. Haastattelu jaettiin strategiseen, sopimusohjaustasoon sekä operatiiviseen tasoon. Haastateltavina oli toimitusketjun eri osapuolia. Työn tuloksena voidaan todeta, että strategian täytäntöönpanossa on vielä tekemistä, etenkin operatiivisella puolella. Sopimusohjausmalliin oltiin tyytyväisiä vaikka myös siitä löytyi vielä kehitettävää. Operatiivisella tasolla toiminnan tehokkuus on noussut verrattuna entiseen malliin, tehokkuutta voidaan kuitenkin vielä monin keinoin nostaa. Yleisesti nähtiin, että koko tilaus-toimitusketjun toiminta on tehostunut ja selkiytynyt.

Motor Types Comparison Determining Efficiency in Pumping Systems

Pumping, fan and compressor systems consume most of the motor electricity power in both the industrial and services sectors. A variable speed drive brings relevant improvements in a fluid system leading to energy saving that further on can be translated into Mtons reduction of CO 2 emissions. Standards and regulations are being adopted for fluid handling systems to limit the less efficiency pumps out of the European market on the coming years and a greater potential in energy savings is dictated by the Energy Efficiency Index (EEI) requirements for the whole pumping system and integrated pumps. Electric motors also have an International Efficiency (IE) classification in order to introduce higher efficiency motors into the market. In this thesis, the applicability of mid-size common electric motor types to industrial pumping system took place comparing the motor efficiency characteristics with each other and by analyzing the effect of motor dimensioning on the pumping system and its impact in the energy consumption.

Efficiency of methods to detect Sclerotinia sclerotiorum in commercial soybean seed lots

Most soybean pathogens are seed transmitted, deserving emphasis the fungus Sclerotinia sclerotiorum, which has been presenting worrying levels of field incidence in some soybean cropping areas in several Brazilian states. The objective of this study was to verify the efficiency of different methods for detecting S. sclerotiorum on soybean seeds artificially infected in the laboratory and from field production areas with a historical disease incidence. Seed samples of seven different cultivars collected from naturally infested fields, and one seed sample artificially inoculated in the laboratory were used. The following detection methods recommended in the literature were compared: Blotter test at 7 ºC, 14 ºC, and 21 ºC; Rolled Paper; and Neon-S. Results demonstrated that these methods showed no repeatability and had a low sensitivity for detecting the pathogen in seeds from areas with disease incidence. They were effective, however, for its detection on artificially inoculated seeds. In the Blotter test method at 7 ºC, there was a lower incidence of other fungi considered undesirable during seed analysis.

Towards a better energy efficiency through a systems approach in an industrial forklift

The purpose of this study is to improve the potential energy recovery to electric energy in an electrohydraulic forklift system. The initial achieved result for energy saving ratio after structural optimization is 40 %. Component optimization is applied to the tested drive which consists of a DTC controlled electric servo motor directly running a reversible hydraulic pump. According to the study the energy efficiency and the energy recovery from the electro-hydraulic forklift system can be increased by 11 % units. New ideas and directions of further research were obtained during the study.

A high efficiency microturbine concept

There is a growing trend towards decentralized electricity and heat production throughout the world. Reciprocating engines and gas turbines have an essential role in the global decentralized energy markets and any improvement in their electrical efficiency has a significant impact from the environmental and economic viewpoints. This paper introduces an inter-cooled and recuperated two-shaft microturbine at 500 kW electric output range. The microturbine is optimized for a realistic combination of the turbine inlet temperature, the recuperation rate and the pressure ratio. The new microturbine design aims to achieve significantly increased performance within the range of microturbines and even competing with the efficiencies achieved in large industrial gas turbines. The simulated electrical efficiency is 45%. Improving the efficiency of combined heat and power (CHP) systems will significantly decrease the emissions and operating costs of decentralized heat and electricity production. Cost-effective, compact and environmentally friendly micro-and small-scale CHP turbine systems with high electrical efficiency will have an opportunity to successfully compete against reciprocating engines, which today are used in heat and power generation all over the world and manufactured in large production series. This paper presents a small-scale gas turbine process, capable of competing with reciprocating engine in terms of electrical efficiency.

Relay protection in active distribution networks

Increasingly growing share of distributed generation in the whole electrical power system’s generating system is currently a worldwide tendency, driven by several factors, encircling mainly difficulties in refinement of megalopolises’ distribution networks and its maintenance; widening environmental concerns adding to both energy efficiency approaches and installation of renewable sources based generation, inherently distributed; increased power quality and reliability needs; progress in IT field, making implementable harmonization of needs and interests of different-energy-type generators and consumers. At this stage, the volume, formed by system-interconnected distributed generation facilities, have reached the level of causing broad impact toward system operation under emergency and post-emergency conditions in several EU countries, thus previously implementable approach of their preliminary tripping in case of a fault, preventing generating equipment damage and disoperation of relay protection and automation, is not applicable any more. Adding to the preceding, withstand capability and transient electromechanical stability of generating technologies, interconnecting in proximity of load nodes, enhanced significantly since the moment Low Voltage Ride-Through regulations, followed by techniques, were introduced in Grid Codes. Both aspects leads to relay protection and auto-reclosing operation in presence of distributed generation generally connected after grid planning and construction phases. This paper proposes solutions to the emerging need to ensure correct operation of the equipment in question with least possible grid refinements, distinctively for every type of distributed generation technology achieved its technical maturity to date and network’s protection. New generating technologies are equivalented from the perspective of representation in calculation of initial steady-state short-circuit current used to dimension current-sensing relay protection, and widely adopted short-circuit calculation practices, as IEC 60909 and VDE 0102. The phenomenon of unintentional islanding, influencing auto-reclosing, is addressed, and protection schemes used to eliminate an sustained island are listed and characterized by reliability and implementation related factors, whereas also forming a crucial aspect of realization of the proposed protection operation relieving measures.

Increased profitability and efficiency by improving the Meetings & Events Category S2P-process – Case Company

The purpose of this research was to examine the most optimal way to arrange meetings and events management and source to pay –process in a global company. The research is a qualitative multi-method case study and is a commission from a global company. The theoretical framework of this research structures around two approaches. First approach focus on a purchasing strategy and management that shows the current role of procure-ment and introduce different ways to organize purchasing functions. Second approach focus on purchasing process management and improvement methods. Annual spend analyze, external and internal interviews and internal survey were done to gain compre-hensive knowledge about the current state of operations and possible solutions. Gathered data were then combined to theoretical framework in order to create optimal solution for the case company. Based on the research a source to pay –process and global policy for meeting and event category was created. The solution includes all relevant matters that are needed in order to secure efficient and profitable operations. The results show that optimal way to arrange meetings and events structures around standardized source to pay –processes, central-ized procurement, preferred supplier and clearly defined roles and responsibilities be-tween different stakeholders.