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349 Uppsatser om Chemical pulp - Sida 18 av 24
Design av försöksanläggning för trycksatt rökgasrening vid oxy-fuelförbränning
Reducing the CO2-pollution, resulting from the combustion of fossil coal for energyproduction, is important to affect environmental changes. One way to achieve a reductionis to use the oxy-fuel technology. The technology uses O2 and re-circulated flue gasduring the combustion which results in a flue gas mainly consisting of CO2. The flue gascould then be compressed and stored without environmental effects. A problem thatfollows from the compression is the risk of acidification in sensitive parts of the process.Acidification can occur because of reactions following from the contact of condensedwater and sulphur- and nitrogen-oxides which are also present in the flue gas.This report compiles and evaluates the basis of a scientific unit with the purpose ofexploring the possibilities of extracting impurities of SOx and NOx from the flue gases.The dimensions of the unit are based on basic conditions, defined for an existing oxy-fuelprocess at Chalmers, and on the results of computer modelling.
Dissolvingmassa baserat på soda-AQ kokning : Potential för ökat förädlingsvärde av svensk skogsråvara
Detta examensarbete genomfördes från begäran av två företag, Pöyry Sweden AB, Karlstad och Kiram AB. Arbetet var uppdelat i två delar, en litteraturstudie samt en experimentell del. I litteraturstudien kartlades olika processer för framställning av dissolvingmassa och olika processer för beredning av viskosfiber. Utöver det sammanställdes även några av de ledande aktörerna av joniska vätskor samt applikationer för cellulosabaserade produkter. Fokus genom hela arbetet har legat på svavelfria processer som t.ex.
Förbättrad planeringspolicy mot lågfrekventa beläggningsprocesser : - I en av Sandviks produktionsenheter
Att ha en god planeringspolicy för samtliga produktionsavsnitt i en produktionsanläggning är en viktig del i en organisation. Inom en industri med många produktvariationer och artiklar är det lämpligt att anpassa flera planeringsmetoder för effektiv planering mot samtliga operationer. I en av Sandviks produktionsenheter för skärtillverkning i Gimo var fokus riktat till att förbättra planeringspolicyn mot lågfrekventa beläggningsprocesser. I denna studie presenterar och optimeras planeringen mot två beläggningstyper vardera inom Physical Vapor Deposition (PVD) och Chemical Vapor Deposition (CVD). I grund för detta examensarbete finns en teoretisk studie, simulering samt fallstudier på Sandvik Coromant AB.
Phosphorus in agricultural soils around the Baltic Sea : comparisons of different laboratory methods as indices for phosphorus leaching to waters
Eutrophication of the Baltic Sea is a serious problem. A major contributing factor is diffuse losses of phosphorus (P) from agricultural land in surrounding countries. In order to estimate P losses, environmental monitoring of small agriculture-dominated catchments is being carried out in most of these countries. Evaluation of the risk of P leaching to waters is usually based on chemical tests originally developed to quantify the amount of soil P available for plant production. The tests are performed in different ways in the different countries and a number of different extraction agents are in use.
Isolating microorganisms from marine and marine-associated samples : a targeted search for novel natural antibiotics
The search for antibiotic compounds from the natural environment has been going on for seven decades, ever since penicillin entered the market and antibiotic treatments became routine. The evolutionary pressure put on the pathogenic microorganisms induced a rapid spreading of naturally occurring resistance genes, leaving only the option of finding new antibiotics to treat the resistant pathogens. Microorganisms have been extensively mined for their biosynthetic abilities to produce biologically active compounds. To date, more than 23 000 microbial natural products have been discovered. The Actinomycetales are ubiquitous bacteria that have been used for antibiotic discovery for more than half a century, and over 10 000 natural products have been identified from the order.
FASTIGHETSPAKETERING : Alltid ett godkänt förfarande?
Chemicals are everywhere in todays society, in humans, animals as well as nature, and they are difficult to avoid. The chemical industry is regarded to be the fastest growing industrial sector, accounting for ten percent of the global economy. A large amount of chemicals are used to produce hygiene products and cosmetics, products that in Sweden only are consumed in quantities of 110 tons per day. Researchers find it increasingly difficult to determine which chemicals that are dangerous and which that are safe, and how they might affect us in the long run. Correlations have been found between chemicals, diseases and other health effects such as cancer, allergies, reproductive and endocrine disorders.
Faror i varor : En studie av unga vuxnas medvetenhet om kemikalier i hygienprodukter och kosmetika
Chemicals are everywhere in todays society, in humans, animals as well as nature, and they are difficult to avoid. The chemical industry is regarded to be the fastest growing industrial sector, accounting for ten percent of the global economy. A large amount of chemicals are used to produce hygiene products and cosmetics, products that in Sweden only are consumed in quantities of 110 tons per day. Researchers find it increasingly difficult to determine which chemicals that are dangerous and which that are safe, and how they might affect us in the long run. Correlations have been found between chemicals, diseases and other health effects such as cancer, allergies, reproductive and endocrine disorders.
Förstudie till våtmark i Rimbo : Design för optimal hydrologi och kväverening
The euthropthication of the Baltic Sea is a threat that is beginning to be taken seriously by the governments concerned. In Sweden, regulations concerning the allowed nitrogen (N) concentration in the effluent water from wastewater treatment plants are being tightened up. The Rimbo wastewater treatment plant has been imposed to reduce the annual mean concentration of total N in the effluent water to levels below 15 mg l-1. A more and more common way to reduce the nitrogen level in wastewater is to let the water pass through a wetland. This study investigates the possibility to build this kind of wetland at the outlet of the Rimbo wastewater treatment plant.A prestudy of the topography, soil characteristics and groundwater flow indicates that the land area in question is well suited for the construction of a wetland.
Provtagning av trädkärnor för att bedöma föroreningsgraden av klorerade lösningsmedel i grundvatten
Chlorinated aliphatic hydrocarbons (CAH´s) were used widely within dry cleaning facilities and for metal degreasing until their toxicity was discovered. PCE is still used as dry cleaning liquid. Today CAH´s are found in soil environment at places where they have been used in the past. The CAH-concentration in trees growing on contaminated land has quite recently received attention as a cheap and effective way of assessing the extent of a CAH-contamination. The method has however, not been put into use in Sweden.The aim of the study has been to investigate whether the CAH-concentration in tree cores could be used to delineate the spread of CAH in a soil environment under Swedish conditions in different seasons.
Fireball 2 : Energieffektiv fiber produktion
The development within the textile industry is always ongoing with development of new andbetter textiles, which often mean the use of non-natural materials like polyester. This doesn?t lineup with the work shared around the world against an improved environment, so the idea came touse a form of linen fibers instead of polyester as the reinforcing material together with cotton.The idea was to use flax, linen of low quality, which is seen as a waste product and garbage inthe production of high quality linen and flax seed oil. This flax of low quality needs to beseparated before it can be used in cotton spinning machines. Fireball 2 is just that, a process toseparate flax fibers through the treatment of a technique called electrohydraulic discharge.The thesis works goal is to evaluate the Fireball 2 process ability to separate flax fiber.
Fosforavskiljning i reaktiva filter vid småskalig avloppsrening
An excessive input of nutrients to lakes and other water bodies has created a problem with eutrophication in Sweden. Untreated, or partially treated, domestic sewage is a major source for discharge of phosphorus (P), which is the nutrient most frequently responsible for eutrophication of most fresh waters and the Baltic Sea. The waste water can be cleaned by filter materials, which have a high P-retention ability and which after saturation may be used as fertilizers. Four potentially suitable filter materials were tested in batch- and column experiments in this study. In the batch experiments, the following materials were shaken with waste water in time series ranging from 5 seconds to 60 minutes: coarse (1-4 mm) and fine (0-2 mm) Polonite® (heated bedrock from Poland); Filtralite® (light expanded clay aggregates with limestone added before burning); water cooled blast furnace slag (BF-slag) and BF-slag mixed with 10% burned limestone.
Skötsel av älgskadade bestånd :
Sweden has today the highest moose (Alces alces) population in the world. The population has been very high since the late seventies and in the beginning of the eighties there was a big ?moose explosion?. The main food source for moose during the winter is young pine (Pinus sylvestris) and birch (Betula spp.). The high moose population has therefore lead to high damage on pine forests over big areas.
Hårdhetsvariation i grundvatten längs Badelundaåsen mellan Leksand och Avesta
Water hardness indicates the concentration of calcium and magnesium ions in water. Water with high concentrations of these ions is described as hard water and water with low concentrations is described as soft water. Water that is too hard or too soft can lead to technical and economical problems. In collaboration with Midvatten AB, groundwater hardness in the Badelunda esker between Leksand and Avesta has been mapped, and an attempt has been made to explain the variations. For this purpose, different GIS programs, such as ArcView, ArcInfo, IDIRISI, and one geochemical modelling program, PHREEQC, has been used.
Tjäderns (Tetrao urogallus L.) vinterdiet i norra Sverige : är gran (Picea abies) viktig i vissa habitat?
In Scandinavia, capercaillie are often associated with pine trees (Pinus sylvestris) in winter, with pine needles as the main diet. Few dietary studies have been conducted in Sweden and winter diet is subject to little debate. The interesting thing is that this "pine specialist? is also found in spruce (Picea abies) forest habitats where pine is scarce or unavailable. In many studies outside Sweden (primarily Central Europe) spruce is regularly observed in the winter diet, but I have found no reports on the selection of the diet in spruce forest areas in Sweden.
Analys av system för rening av avloppsvatten i en anaerob membranbioreaktor
The most common way to treat wastewater in Sweden today is by a combination of an activated sludge process and a chemical treatment. These processes are not very energy efficient and may not be the most environmentally friendly. That is why it is interesting to evaluate new alternative methods to see if they can be less harmful to the environment and help to a lower resource consumption. New techniques are tested in a pilot installation at Hammarby Sjöstad, Sjöstadsverket. To be able to evaluate these techniques in a wide perspective system analyses are conducted where different impacts can be considered, advantages and disadvantages in the systems.Five system structures for water treatment have been constructed in Matlab/Simulink in this study.