• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 1
  • 1
  • Tagged with
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Moderna alternativ för skänkvärmning inom gjuteribranschen / Modern alternatives for ladle preheating in foundries

Nyberg, Erik, Ahlstrand, Linus January 2020 (has links)
Sveriges och världens industrier står inför stora omställningar gällande energianvändning och klimatavtryck. Johnson Metall AB jobbar ständigt med miljöarbete och har identifierat gasolanvändningen i produktionen som ett ställe där stora miljövinster går att göra. Examensarbetet avgränsas till att enbart titta på alternativa förvärmningstekniker till skänkar.Syftet med rapporten är att undersöka 3-5 alternativa förvärmningstekniker till den gasoluppvärmning som används i dagsläget. Det är viktigt att en alternativ lösning gör så att nuvarande produktkvalitet bibehålls samtidigt som en alternativ lösning bidrar till ett lägre klimatavtryck, det är även viktigt att priset på produkterna inte går upp allt för mycket.För att genomföra examensarbetet har metoderna litteratursökning, Double Diamond, nulägesanalys, komparation och kriterieviktsmetoden använts. För att skapa en bild över uppvärmningsförloppet görs en testmätning som jämförs med teoretiska samband.Utbudet av klimatavtrycksminskande teknik är relativt stor och fortsätter att växa, däremot råder det brist på incitament att byta teknik. Det krävs stora investeringar i ny teknik som är relativt obeprövad. Bränslen som skulle kunna nyttjas blir indirekt reserverade för andra teknikslag till följd av konkurrensen på bränslemarknaden. I dagens läge ligger risktagandet i övergången till ny klimatneutral teknik hos industrin.Det alternativ som har störst potential är en elektrisk lösning. Förändringar i anläggningen kommer inte innebära någon större inverkan i produktionen. Konsekvenserna av att byta förvärmningsteknik är att produkterna förmodligen kommer öka i pris, men att produkten också får ett lägre klimatavtryck. / Due to the consequences of global warming the industries of the world are facing new challenges. Johnson Metall AB is continuously working with ways to reduce their environmental footprint. Johnson Metall AB has identified use of liquid petroleum gas (LPG) as a source where great environmental gains can be made. The thesis limits itself to only look at LPG use in ladle preheating.The purpose of the thesis is to investigate 3-5 alternative ladle preheating technologies instead of the current LPG preheating of ladles. It is important that an alternative solution keeps the current quality of the products and contributes to lower emissions, it is also important that the price of the products doesn’t increase too much. In order to investigate available options the following methods have been used: literature study, double diamond, current situation analysis, comparison method, and the criterion weight method. In order to create a picture of the heating of ladles, an evaluation measure is performed and compared with theoretical concepts. Climate friendly alternatives are present on the market and are continuously improving, however the incentives to invest in new technologies are few. From the industries perspective the available options are expensive and relatively untested. Fuels that are viable options are taken from consideration due to hard competition with other markets. Moving to alternative fuels is a risky business with few guarantees for the foundry industries. The alternative with the biggest potential is an electric solution. Changes in the facility will not result in any major interference in production. The consequences of changing ladle preheating technology will probably be an increase in the price of the products, however the product will be more environmentally friendly.
2

From recovery boiler to integration of a textile fiber plant : Combination of mass balance analysis and chemical engineering

Magnusson, Hans January 2015 (has links)
Modern chemical technology is an efficient tool for solving problems, particularly within the complex environment of the pulp and paper industry, and the combination of experimental studies, mill data and mass balance calculations are of fundamental importance to the development of the industry. In this study various examples are presented, whereby chemical technology is of fundamental importance. It is well documented that under normal conditions the molten salt mixture from the kraft recovery boiler flows down into the dissolving tank without problems. However, in the case of  alternatives to the kraft recovery boiler, knowledge of more precise data of the molten salts is required for the design calculations. In this study the viscosity for the case of sodium carbonate and 30 mole% sulphide has been measured and is of the magnitude 2 – 3 cP at temperatures relevant for a recovery boiler, i.e. similar to water at room temperature. The presence of non-process elements (NPE) in a typical pulp mill has been investigated. The main input is with regards to the wood, and anticipated problems include; deposits in evaporators, high dead-load in liquor streams, plugging of the upper part of the recovery boiler and decreasing efficiency in the causticization department. Efficient green liquor clarification is of the greatest importance as an efficient kidney for many NPE. Mill data and calculations show that the magnesium added in the oxygen delignification does not form a closed loop. Integration of a prehydrolysis kraft pulp mill producing dissolving pulp with a plant producing viscose textile fiber could be highly beneficial. The prehydrolysis liquor will contain both sugars and acetic acid. It is however not possible to fully replace the sulphuric acid of the viscose spinning bath with acetic acid of own production. The sulphuric chemicals from the viscose plant can be partly taken care of in the kraft recovery area as well as the viscose plant which can be supplied with alkali and sulphuric acid. Zinc-containing effluents from the viscose plant can be treated with green liquor to precipitate zinc sulphide. / Modern chemical technology is an extremely efficient tool for solving problems particularly in a complicated environment such as the pulp and paper industry. Here, examples are studied during which chemical technology is of fundamental importance. At normal conditions the molten salt mixture from the kraft recovery boiler flows down into the dissolving tank without hindrance. However, for certain kraft recovery boiler alternatives, knowledge of more precise data of the molten salts is required. The viscosity for the case of sodium carbonate and 30 mole% sulphide has been measured and is of the magnitude 2 – 3 cP at relevant temperatures. The main input of non-process elements (NPE) is down to the wood, and known problems include deposits in evaporators and decreasing efficiency in the causticization department. Green liquor clarification is an efficient kidney for many NPE. Magnesium added in the oxygen delignification does not form a closed loop. Integration of a prehydrolysis kraft pulp mill producing dissolving pulp with a plant producing viscose textile fiber could be of significant interest, as the handling of both alkali and sulphuric compounds can be integrated. Problems will however arise as the capacity of the pulping line and the chemical recovery has to be adjusted.

Page generated in 0.0198 seconds