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1
Ribeiro, Júlio César Torres. „Smelt spout corrosion in a recovery boiler“. Universidade Federal de Viçosa, 2010. http://locus.ufv.br/handle/123456789/5896.
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Previous issue date: 2010-06-14Acidentes com Bicas de Smelt são reportados pelo Black Liquor Recovery Boiler Advisory Committee, BLRBAC, e constituem uma preocupação real de segurança sob o ponto de vista operacional. Tipicamente o smelt escorre através de bicas refrigeradas a água da fornalha para o tanque dissolvedor e uma falha pode levar a explosões pelo contato água-smelt. Este trabalho estuda um caso real onde condições severas de corrosão culminaram com a falha em serviço de uma de seis bicas em uma caldeira de recuperação na CENIBRA. A falha resultou em grande volume de água de resfriamento entrando na caldeira e em contato com smelt ao redor da abertura da bica, mas felizmente não ocorreram explosões água-smelt. Uma elaborada investigação foi conduzida para se determinar as causas da falha da bica. Conclui-se que a falha foi causada por fluxo insuficiente de água de resfriamento para a bica de smelt, que, por sua vez, foi causada por uma seqüência de eventos que ocorreram após uma falha geral no sistema de geração de energia elétrica da fábrica. O estudo do evento levou ao desenvolvimento e implantação de procedimentos operacionais e de manutenção que tem por objetivo assegurar fluxo de água de resfriamento adequado para as bicas de smelt para prevenção de falhas recorrentes.
Smelt Spout accidents are reported by Black Liquor Recovery Boiler Advisory Committee, BLRBAC, and constitute a real safety concern from the operational point of view. Typically smelt flows through water cooled spouts from furnace to the smelt dissolving tank and a failure can lead to smelt-water contact explosions. This work studies a real case where severe corrosion led to an in-service failure of one of the six spouts on a recovery boiler at Cenibra. The failure resulted in a large amount of cooling water entering the boiler and contacting smelt around the spout opening, but fortunately no smelt-water explosion occurred. An extensive investigation was conducted to determine the causes of the spout failure. It was concluded that the failure was caused by insufficient cooling water flow to the smelt spout, which, in turn, was caused by a sequence of events that occurred after a general black out of an electrical energy system at the mill. The experience has led to the development and placement of operating and maintenance procedures that ensure adequate cooling water flow to smelt spouts to prevent future failures.
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Fakhrai, Reza. „Black liquor conbustion in Karft Recovery Boiler-Numerical Modelling“. Doctoral thesis, KTH, Materialvetenskap, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3348.
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Edberg, Alexandra. „Monitoring Kraft Recovery Boiler Fouling by Multivariate Data Analysis“. Thesis, KTH, Skolan för kemi, bioteknologi och hälsa (CBH), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-230906.
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This work deals with fouling in the recovery boiler at Montes del Plata, Uruguay. Multivariate data analysis has been used to analyze the large amount of data that was available in order to investigate how different parameters affect the fouling problems. Principal Component Analysis (PCA) and Partial Least Square Projection (PLS) have in this work been used. PCA has been used to compare average values between time periods with high and low fouling problems while PLS has been used to study the correlation structures between the variables and consequently give an indication of which parameters that might be changed to improve the availability of the boiler. The results show that this recovery boiler tends to have problems with fouling that might depend on the distribution of air, the black liquor pressure or the dry solid content of the black liquor. The results also show that multivariate data analysis is a powerful tool for analyzing these types of fouling problems.Detta arbete handlar om inkruster i sodapannan pa Montes del Plata, Uruguay. Multivariat dataanalys har anvands for att analysera den stora datamangd som fanns tillganglig for att undersoka hur olika parametrar paverkar inkrusterproblemen. Principal·· Component Analysis (PCA) och Partial Least Square Projection (PLS) har i detta jobb anvants. PCA har anvants for att jamfora medelvarden mellan tidsperioder med hoga och laga inkrusterproblem medan PLS har anvants for att studera korrelationen mellan variablema och darmed ge en indikation pa vilka parametrar som kan tankas att andras for att forbattra tillgangligheten pa sodapannan. Resultaten visar att sodapannan tenderar att ha problem med inkruster som kan hero pa fdrdelningen av luft, pa svartlutens tryck eller pa torrhalten i svartluten. Resultaten visar ocksa att multivariat dataanalys ar ett anvandbart verktyg for att analysera dessa typer av inkrusterproblem.
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Tan, Geng. „Cooling characteristics and thermal properties of kraft recovery boiler smelt“. Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0027/MQ50374.pdf.
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Nikfarman, Hanieh. „Determination of thermal conductivity of recovery boiler char bed materials“. Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0016/MQ58746.pdf.
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Meyer, Joseph Freeman. „Recovery boiler superheater corrosion - solubility of metal oxides in molten salt“. Thesis, Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/47742.
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The recovery boiler in a pulp and paper mill plays a dual role of recovering pulping chemicals and generating steam for either chemical processes or producing electricity. The efficiency of producing steam in the recovery boiler is limited by the first melting temperature of ash deposits that accumulate on the superheater tubes. Above the first melting temperature, the molten salt reacts with the protective oxide film that develops and dissolves it. The most protective oxide is determined by evaluating how little it dissolves and how its solubility changes in the molten salt. Solubility tests were done on several protective oxides in a known salt composition from a recovery boiler that burns hardwood derived fuel. ICP-OES was used to measure concentration of dissolved metal in the exposure tests while EDS and XRD were used to verify chemical compositions in exposure tests. NiO was found to be the least soluble oxide while Cr₂O₃ and Al₂O₃ had similar solubility with Fe₂O₃ being less soluble than Cr₂O₃ but more soluble than NiO. Exposure tests with pure metals and selected alloys indicated that even though Fe₂O₃ has little solubility, it is not a protective oxide and causes severe corrosion in stainless steels. The change in performance of iron based alloys was due to the development of a negative solubility gradient for Fe₂O₃ where Fe₂O₃ precipitated out of solution and created a continuous leaching of oxide. Manganese was found to be beneficial in stainless steels but its role is still unknown. Nickel based alloys were found to be least corroded due to nickel's low solubility and because it did not form a negative solubility gradient.
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Jansson, Johan. „Economical optimization of steam data for recovery boilers“. Thesis, Umeå universitet, Institutionen för tillämpad fysik och elektronik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-144328.
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Pulp and paper mills are high power consuming industries. Pulp and integrated mills produce power via steam turbines in recovery boilers. Due to high power prices and the fact that biomass combusted in the recovery boiler is considered as green energy, there is today a desire to always increase the power generation when investing in new recovery boilers. In order to increase power output from the steam turbine the steam data (i.e temperature and pressure) needs to be increased. With higher steam temperature follows a higher risk of corrosion due to the non process element potassium in the boiler fuel. The uncertainties of high temperature corrosion and the unpredictable environment in the furnace makes it difficult to design recovery boilers. This results in higher investment cost and could lead to less profit for the mill buying the boiler. The question then stands whether the revenue obtained from the higher power generation, is higher than the investment made for the upgrade in order to produce the higher steam data over a certain time. And more specifically what steam data will be the most economical, when comparing revenue from power generation with investment cost? In this study, together with ÅF Industry AB, four boilers with different steam data (Boiler A: 38.5 bar, 450°C; Boiler B: 92 bar, 480°C; Boiler C: 106 bar, 500°C; Boiler D: 115 bar, 515°C) were compared. The boilers were compared for four potassium levels: 1.0wt%, 1.5wt%, 2.5wt%, 3.5wt%. And two values of power were used, 300 SEK/MWh and 700 SEK/MWh. The marginal differences between the boilers were: the amount of material used in the superheaters in order to produce different steam data; the type of material used in the superheaters and the furnace; whether an ash-treatment system was needed (in order to purge potassium from the process); the turbines and generators; whether a feed water demineralization equipment was needed; the yearly cost for make-up chemicals (due to usage of an ash-treatment system) and the amount of power generated. The boilers investment cost and net yearly revenue were compared in order to determine the marginal pay-off in years. The most economical choice of boiler for the different potassium levels for 300 SEK/MWh: 1.0wt%, Boiler D; 1.5wt%, Boiler C; 2.5wt%, Boiler B; 3.5wt%, Boiler D (A). And for 700 SEK/MWh: 1.0wt%, Boiler D; 1.5wt%, Boiler C; 2.5wt%, Boiler D (B); 3.5wt%, Boiler D. The conclusion in this thesis was that the deciding factor is whether the boiler is in need of an ash-treatment system. Higher steam data is preferable as long as ash-treatment can be avoided. However, when comparing two boilers with ash-treatment the one with higher steam data is more feasible. Low steam data, such as boiler A, will never be feasible, regardless of potassium level and value of power.
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Delaney, James Carroll. „Suppression of vapor explosions during rapid quenching of char beds in chemical recovery boilers“. Thesis, Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/17780.
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Rezvani, Jorshari Keyvan. „Effects of potassium and carbonate on the deposition of synthetic recovery boiler carryover particles“. Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0015/MQ53346.pdf.
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Kermani, Kayhan. „Numerical modeling of sootblower jet flow between superheater platens in a kraft recovery boiler“. Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ58744.pdf.
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Pathania, Nanan. „A study of composition of kraft recovery boiler carryover particles using an Entrained Flow Reactor“. Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/MQ62920.pdf.
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Ip, Leong-Teng. „Comprehensive Black Liquor Droplet Combustion Studies“. Diss., CLICK HERE for online access, 2005. http://contentdm.lib.byu.edu/ETD/image/etd677.pdf.
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Kifleyesus, Biniam Okbaendrias. „Eneregy Management In Industries : Analysis of Energy Saving potential by Steam conedensate recovery“. Thesis, Högskolan i Gävle, Energisystem, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-25090.
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When speaking about energy it means speaking about life, activity, economy, growth and environmental issues. The issue of energy has been the main article all over the world in recent years, this is due to the importance of energy to life and its impact on the environment. For example, Paris climate change meeting in 2015 is one of the recent global meeting which directly related to the energy use by nations. The meeting was mainly focused up on the restriction of greenhouse gas emission which implies that industries should think about other alternative energy resources rather than fossil fuel for positive impact on climatic change. This is one of the cases that led industries into greater competition in the global market. Industries must consider energy alternatives which is safe for the environment and by using such energy a competitive product with better quality and quantity should be produced. This challenge has motivated industries to look and study the energy that they are using currently. Studies and researches show that one of the main and most abundant energy resources that most of these industries can get is by improving the energy efficiency or managing the energy that they currently use. The main aim of this thesis is to provide Arizona chemical plant (Kraton) at Sandarne on the potential energy saving by managing their energy use. The first wisdom in energy utilization is managing and using the energy they possess efficiently. In Arizona plant at Sandarne, the product named “Pitch” (a natural viscoelastic polymer or rosin) is a fuel used as the primary energy supply for the production of steam by boilers. The steam may be utilized well but the energy in the condensate (after steam loses its latent heat) is not addressed well enough. Hence this paper has studied on how significant is the energy lost by the steam condensate is and how its recovery can be used to save energy and cost. The plant produces about an average of 11.42 ton of steam each hour in a year. This steam can be returned or fully recovered (100%) as condensate from the law of conservation of mass since only energy is lost from the steam. But the plant returns a maximum of about 3ton of condensate each hour. This amount is relatively low compared to the amount of condensate recovery possibility. Recovery possibility of condensate return showed that the plant at Sandarne can return at least 8.5 ton of condensate each hour. In comparison with the current return estimated 5.5 ton of condensate is being lost simply as waste each hour leading to about 400 SEK minimum cost loss. The calculation of cost is in minimum because the charge from water supply and condensate effluent disposal charge are not considered. In this paper only recovery from the easily recoverable steam condensate is being considered (25% of the system) which resulted in payback time of the proposed investment 1.88 years without considering the above explained charges. It is much motivating study considering the generalized approach and over simplified method. If a deeper investigation is made on the potential, it can be clearly shown that how significant the potential is in securing and sustaining energy and environmental issues. Ensuring the security and sustainability of energy which addresses the environmental issue precisely will help the plant to stay on the race of global market competition. Keywords: Energy efficiency, Boiler efficiency, Energy management, Condensate recovery,
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Magnusson, Hans. „From recovery boiler to integration of a textile fiber plant : Combination of mass balance analysis and chemical engineering“. Licentiate thesis, Karlstads universitet, Institutionen för ingenjörs- och kemivetenskaper, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-37266.
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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.
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Estes, Matthew J. „Corrosion of composite tube air-ports in kraft recovery boiler: Cr₂O₃, Fe₂O₃, NiO solubility in molten hydroxide“. Diss., Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/7027.
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Kulas, Gregory S. „An investigation of some factors affecting the corrosion of carbon steel boiler tube material exposed to simulated kraft smelt“. Diss., Georgia Institute of Technology, 1989. http://hdl.handle.net/1853/5494.
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Primes, Alois. „Modularní horizontální kotel – HRSG“. Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2021. http://www.nusl.cz/ntk/nusl-443235.
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This thesis deals with the design of a Heat Recovery Steam Generator (HRSG). Theintroductory part is devoted to a brief description of the boiler, the specified parametersand the compilation of the temperature profile. The main computational part of thiswork is divided into 6 parts. The first contains preparatory calculations, including thecalculation of boiler eiciency. In the second part, a flue gas duct is designed. This isfollowed by a thermal calculation of the boiler for all heat exchange surfaces. The last 3parts deal with the design of the drum, piping and the loss of boiler draft calculation.
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Pettersson, Anita. „Characterisation of Fuels and Fly Ashes from Co-Combustion of Biofuels and Waste Fuels in a Fluidised Bed Boiler. A Phosphorus and Alkali Perspective“. Doctoral thesis, Göteborg : Chalmers University of Technology, 2008. http://hdl.handle.net/2320/3957.
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Drewes, Carl. „Effektförlustutredning : Effektförlustutredning av en mindre sodapanna tillhörande ett medelstort massabruk, en fallstudie“. Thesis, Högskolan i Gävle, Energisystem och byggnadsteknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-32419.
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The industrial sector in Sweden stands for 38 percent of the total energy use. Within these 38 percent the pulp and paper industry stand for about half of the energy use. Due to the extent of the energy use it is important that we do what we can to keep the energy usage as low as possible within our industries. In this bachelor thesis a case study is performed regarding a problem with a recovery boiler which belong to one of Stora Ensos pulp mills in a small town called Skutskär in Sweden. The problem with the recovery boiler is that it does not reach the temperature of the outgoing steam for which the soda boiler was designed, which causes the efficiency to suffer. The problem with the recovery boiler is not sustainable either in terms of energy use or economy. Recovery boiler 6 (RB6) as it is called is one of two recovery boilers belonging to the pulp mill. Both boilers are designed to produce high pressure steam at 56 bar and 450°C. The high-pressure steam produced goes through a back-pressure turbine where the pressure is lowered to the working pressure of the remaining factory while electricity is produced. Steam at a lower temperature results in lower enthalpy, which in turn will affect the electricity generation in the back-pressure turbine. The purpose of the study is to quantify the loss in electricity generation caused by the lack of steam temperature of RB6. As well as investigating the causes of the lack of heat transfer where the goal is to locate the problem area. A literature study was conducted regarding the efficiency of the recovery boiler, where much emphases was placed on the function of the superheater and the soot system. The superheater accounts for about 30 percent of all heat transfer in a recovery boiler and is directly crucial for reaching the final temperature of the steam. In the literature study, among other things, the design and fouling of superheater is studied to see that if affects the heater transfer. Further, the soot system effect on the heat transfer is also studied and it shows that the soot system has a greatly influence of the final heat transfer. The method used to conduct the study is primarily data analysis. The pulp mills internal analysis program WinMops is used in combined with Excel to analyze operational data. First, the magnitude of the problem was investigated by calculating the effect of RB6’s lack of steam temperature on the total enthalpy of the steam reaching the turbine. Calculations were made for electricity generation in normal cases and under the influence of RB6, where the difference was considered as lost electricity generation. Once the size of the problem was determined, the investigation of causes of heat transfer began, with the superheater coming into focus. The results of the case study show that RB6’s lack of steam temperature causes a loss of electricity production equivalent to 7 million SEK in a normal year and a year with a low electricity price, this amount to 3 million SEK. Whit regard to the second investigation, it is very likely that the superheater causes the temperature drop. However, the study shows that the superheater has no smaller heat transfer surface in relation to the other recovery boiler and that the heat transfer rate is also not deviant. The superheater shows a hint of fouling at the same time as the flow of soot steam is slightly lower on RB6, unlike the mill’s other recovery boiler. An interesting phenomenon that emerges in the study is that the tertiary air flow tends to have a greater effect on RB6 outgoing steam flow than expected.Industrisektorn står för omkring 38 procent av Sveriges totala energianvändning. Av de 38 procenten står pappers- och massaindustrin för omkring hälften av all energianvändning. Eftersom industrin är en omfattande del gällande energianvändningen är det viktigt att åtgärder utförs för att hålla energianvändningen så låg som möjligt. I detta examensarbete utförs en fallstudie gällande ett problem med en sodapanna som tillhör Stora Ensos massabruk i Skutskär. Problematiken med sodapannan är att den inte når upp i den temperaturen på utgående ångan som sodapannan designades för vilket gör att verkningsgraden blir lidande. Problemet med sodapannan är inte hållbart både sett till energianvändning eller ekonomi. Sodapanna 6 (SP6) som den kallas är en av två sodapannor som tillhör massabruket. Båda sodapannorna är designade för att producera högtrycksånga vid 56 bar och 450°C. Högtrycksångan som produceras går via en mottrycksturbin där trycket sänks till arbetstrycken för resterande fabriken samtidigt som el produceras. Ånga vid lägre temperatur medför lägre entalpi vilket i sin tur kommer att påverka elproduktionen i motrycksturbin. Syftet med studien är att kvantifiera förlusten i elproduktion som den bristande ångtemperaturen av SP6 orsakar. Utöver det är syftet även att utreda orsaker till den bristande värmeöverföringen där målet är att lokalisera problemområdet. En litteraturstudie utfördes gällande effektivitet kring sodapannan varvid mycket tyngd lades på överhettarens samt sotningens funktion. Överhettaren står för omkring 30 procent av all värmeöverföring i en sodapanna och är direkt avgörande för att nå sluttemperaturen på ångan. I litteraturstudien studeras bland annat utformning och försmutsning av överhettaren för att se hur det påverkar värmeöverföringen. Vidare studeras sotningens påverkan på värmeöverföringen och även den påverkar i stor grad den slutgiltiga värmeöverföringen. Metoden som används för att genomföra studien är framförallt dataanalys. Massabrukets interna analyseringsprogram WinMops används tillsammans med Excel för att kunna analysera driftdata. Först utreddes storleken på problemet med hjälp av att beräkna hur stor påverkan SP6 bristande ångtemperatur har på den totala entalpin på ångan som når turbin. Beräkningar utfördes för elproduktion vid normalfall och vid påverkan av SP6 varvid skillnaden betraktades som den förlorade elproduktionen. När problemets storlek var fastställt började utredningen kring orsaker till bristande värmeöverföring varvid överhettaren hamnade i fokus. Studiens resultat visar att SP6 bristande ångtemperatur orsakar en elproduktionsförlust som motsvarar 7 miljoner kronor ett normalår och ett år med lågt elpris rör det sig om 3 miljoner kronor. Gällande den andra utredningen är det med stor sannolikhet överhettaren som orsakar temperaturfallet. Däremot visar studien att överhettaren inte har någon mindre värmeöverförande yta i förhållande till den andra sodapannan samt att värmeöverföringstalet är inte heller avvikande. Överhettaren visar en antydan på försmuttning samtidigt som sotångflödet är något lägre på SP6 till skillnad från brukets andra sodapanna. Intressant fenomen som dyker upp i studien är att tertiärluftflödet tenderar att ha en större påverkan på SP6 utgående ångflöde än förväntat.
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Ferreira, Daniel José de Oliveira. „Modelagem de caldeira de recuperação química Kraft“. Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/3/3137/tde-26072013-122445/.
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O avanço da capacidade do processamento dos computadores e do desenvolvimento de métodos numéricos tem proporcionado ferramentas de modelagem, projeto e otimização cada vez mais eficientes para a constante melhoria de caldeiras de recuperação química Kraft. Dentre as técnicas utilizadas, os modelos CFD abrangentes tem sido empregados nos últimos anos para representar a operação da caldeira de recuperação considerando o maior número possível processos vinculados ao escoamento dos gases de combustão. O presente trabalho busca desenvolver um modelo CFD abrangente considerando o escoamento turbulento dos gases de combustão, o arraste das gotas de licor, a combustão homogênea dos voláteis em fase gasosa, as etapas de combustão heterogênea do licor preto e uma representação simplificada do leito carbonizado. Os resultados se mostraram coerentes com o comportamento apresentado na literatura. A simulação do modelo permite análise dos projetos e das operações da caldeira.The advance of computer processing power and the development of numerical methods promote more efficient tools for modeling, design and optimization aiming to increase improvements in Kraft recovery boilers. Among the available techniques, the comprehensive CFD models have been applied in the last years to represent the recovery boiler operation considering as much as possible processes linked with flue gas flow. The objective of present work is the development of a comprehensive CFD model considering turbulent flue gas flow, black liquor droplets drag, volatiles homogeneous combustion in gas phase, the steps of heterogeneous black liquor combustion and the simplified interaction between flue gas flow and char bed. The results have good agreement with boiler behavior presented in the literature. The simulation of the comprehensive model allows the analysis of design and operations of the boiler.
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Sobotka, Tomáš. „Modernizace a ekologizace teplárny“. Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2012. http://www.nusl.cz/ntk/nusl-230033.
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The target of this diploma thesis is design of cogeneration unit with following requirements: • Installation of new unit instead of the old and used up one. • Electric energy supply within Supportive service – fast starts • Greening (replacement of coal with natural gas) At the beginning I deal with the current state of old unit. In the next part there is the design of new technological unit, which consists of design of boilers, gas engines, steam turbines. Final phase of the thesis includes economical analysis focused on setting of financial return.
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Mikkanen, Pirita. „Fly ash particle formation in kraft recovery boilers /“. Espoo [Finland] : Technical Research Centre of Finland, 2000. http://www.vtt.fi/inf/pdf/publications/2000/P421.pdf.
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Tran, Tony. „Soap separation efficiency at Gruvön mill : An evaluation of the process before and after a modification“. Thesis, Karlstads universitet, Fakulteten för teknik- och naturvetenskap, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-7330.
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Wood consists not only of cellulose, lignin and hemicellulose but also of so called extractives which includes fats and acids and these components are separated in the mill from the black liquor. These extractives are in the mill denoted as tall oil soap. Tall oil has a large field of applications like chemicals and fuel and as it is produced to the atmosphere if it can replace oil and thus reduce the oil consumption. Tall oil soap is separated from the black liquor in a skimmer and the focus of this thesis was to examine the effect of air injection and the soap layer thickness on the soap separation efficiency in a skimmer. The work was focused on in analyzing the soap content of the inlet and outlet black liquor flow of the skimmer and to detect if an enhancement has been achieved with the two mentioned methods. The reason for the pulp mill to improve the soap separation efficiency was to decrease the risk of foaming and fouling in the evaporator but also to be able to increase the production of tall oil. The air injection gave a 41% improvement of the soap separation efficiency and further improvements are probably possible to achieve. The air injection flow was about 7 l air /m3 liquor in the black liquor feed. The airflow lowers the density of soap, creating a greater difference in density between soap and black liquor and this improves the separation efficiency. A thicker soap layer could increase the likelihood for soap drops to raise and reach the soap-liquor interface, because the soap drops have the tendency to bind with each other and will be separated from the liquor instead of following with the skimmed liquor outlet (fig. i.2). However, this study shows no indication of improvement with thicknesses that exceeds 0,75- 3,5 m which also endanger the skimmer due to overflow from the skimmer or create a short circuit between the in- and the outlet black liquor flow.
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Dlouhá, Kristýna. „Návrh HRSG kotle“. Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2019. http://www.nusl.cz/ntk/nusl-401508.
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This master’s thesis deals with the design of a heat recovery steam generator. The introductory part of the thesis is dedicated to waste heat boilers, their division and their utilization in combined cycles gas turbine. In the following chapter, an analysis of the existing combined heat and power plant operation is performed. In the next part of the thesis, the conceptual layout of the new source is designed. Subsequently, the thermal calculation of the boiler is carried out as well as the design of individual heat exchanging surfaces. The sixth chapter deals with the strength calculation of the boiler and the outer piping, chambers and drum are designed here. At the end of the thesis there are described off-design states of the new combined cycle gas turbine.
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Goerg, Kristin A. „A Study of fume particle deposition“. Diss., Georgia Institute of Technology, 1989. http://hdl.handle.net/1853/5570.
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Hallman, L. (Lauri). „Single photon detection based devices and techniques for pulsed time-of-flight applications“. Doctoral thesis, Oulun yliopisto, 2015. http://urn.fi/urn:isbn:9789526210445.
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Abstract In this thesis, a new type of laser diode transmitter using enhanced gain-switching suitable for use with a single photon avalanche diode (SPAD) detector was developed and tested in the pulsed time-of-flight laser range finding (lidar) application. Several laser diode versions were tested and the driving electronics were developed. The driving electronics improvements enabled a pulsing frequency of up to 1 MHz, while the maximum laser output power was about 5–40 W depending on the laser diode dimensions. The large output power is advantageous especially in conditions of strong photon noise emerging from ambient light outdoors. The length of the laser pulse matches the jitter of a typical SPAD detector providing several advantages. The new laser pulser structure enables a compact rangefinder for 50 m distance measurement outdoors in sunny conditions with sub-centimeter precision (σ-value) at a valid distance measurement rate of more than 10 kHz, for example. Single photon range finding techniques were also shown to enable a char bed level measurement of a recovery boiler containing highly attenuating and dispersing flue gas. In addition, gated single photon detector techniques were shown to provide a rejection of fluorescent photons in a Raman spectroscope leading to a greatly improved signal-to-noise ratio. Photonic effects were also studied in the case of a pulsed time-of-flight laser rangefinder utilizing a linear photodetector. It was shown that signal photon noise has an effect on the optimum detector configuration, and that pulse detection jitter can be minimized with an appropriate timing discriminatorTiivistelmä Tässä työssä kehitettiin uudentyyppinen, tehostettua "gain-switchingiä" hyödyntävä laserdiodilähetin käytettäväksi yksittäisten fotonien avalanche-ilmaisimien (SPAD) kanssa, ja sitä testattiin pulssin lentoaikaan perustuvassa laseretäisyysmittaussovelluksessa. Useita laserdiodiversioita testattiin ja ohjauselektroniikkaa kehitettiin. Ohjauselektroniikan parannukset mahdollistivat jopa 1 MHz pulssitustaajuuden, kun taas laserin maksimiteho oli noin 5–40 W riippuen laserdiodin dimensioista. Suuri lähtöteho on edullinen varsinkin vahvoissa taustafotoniolosuhteissa ulkona. Laserpulssin pituus vastaa tyypillisen SPAD-ilmaisimen jitteriä tarjoten useita etuja. Uusi laserpulssitinrakenne mahdollistaa esimerkiksi kompaktin etäisyysmittarin 50 m mittausetäisyydelle ulkona aurinkoisessa olosuhteessa mm–cm -mittaustarkkuudella (σ-arvo) yli 10 kHz mittaustahdilla. Yksittäisten fotonien lentoaikamittaustekniikan osoitettiin myös mahdollistavan soodakattilan keon korkeuden mittauksen, jossa on voimakkaasti vaimentavaa ja dispersoivaa savukaasua. Lisäksi portitetun yksittäisten fotonien ilmaisutekniikan osoitettiin hylkäävän fluoresenssin synnyttämiä fotoneita Raman-spektroskoopissa, joka johtaa selvästi parempaan signaali-kohinasuhteeseen. Fotoni-ilmiöitä tutkittiin myös lineaarista valoilmaisinta hyödyntävän pulssin kulkuaikamittaukseen perustuvan lasertutkan tapauksessa. Osoitettiin, että signaalin fotonikohina vaikuttaa optimaaliseen ilmaisinkonfiguraatioon, ja että pulssin ilmaisujitteri voidaan minimoida sopivalla ajoitusdiskriminaattorilla
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Nwabueze, Obiefuna. „Effect of SO¦2 on dust sintering in kraft recovery boilers“. Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ58747.pdf.
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Jones, Andrew K. „A Model of the kraft recovery furnace“. Diss., Georgia Institute of Technology, 1989. http://hdl.handle.net/1853/5754.
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Vafa, Shermineh. „A transient numerical algorithm to predict temperature and liquid content of carryover in kraft recovery boilers“. Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/MQ62927.pdf.
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Slíva, Karel. „Návrh dvoutlakého horizontálního kotle na odpadní teplo“. Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2016. http://www.nusl.cz/ntk/nusl-254297.
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The focus of this thesis is a proposal of a horizontal dual-pressure heat recovery steam generator. The introductory part includes thermal calculation, as well as a design of the layout and a design of the heat transfer surfaces and the layout of the boiler. Individual chapters are broken down according to the outline of the proposal for the arrangement of the heating surfaces, according to the parameters of the flue gas and steam. The master thesis contains a scheme of a real heat transfer temperature diagram and it also includes the calculation of connecting and downcomer pipes and drums. The final part describes the calculation of the boiler draft loss. The main idea of the thesis is accompanied by the technical documentation of the drawing of the boiler.
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Malbrue, Courtney Michelle. „An Examination of Heavy Metal Vaporization from the Combustion of Black Liquor“. Thesis, Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/13949.
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The research focuses on the fate of heavy metals and their emissions from pulp mill recovery boilers. Heavy metals are extremely toxic and cause adverse effects on human health. There is limited information about factors affecting heavy metal vaporization from recovery boilers, in which spent pulping liquors, (also called black liquor) is burnt. The heavy metals are present in trace quantities in black liquor. They are emitted in the air as submicron particles, and their amount of emission depends on the input of metals into the recovery boiler, volatilization of metals in the boiler and the efficiency of the electrostatic precipitator (ESP) to remove the metals. The heavy metals vaporization from different recovery boilers vary widely and the reason is not known. My thesis will focus on determining what conditions affect the volatility of the heavy metals, and whether differences in heavy metal vaporization are due to differences in boiler operating conditions or the composition of the liquor.
I will examine black liquor pyrolysis, combustion and gasification in well-controlled laboratory conditions. I will analyze three different black liquors. The liquors will be spray-dried and burnt or gasified in a laminar entrained-flow reactor at high temperatures of 1000-1100C and residence times ranging from 0.5 to 1.5 s. Equilibrium calculations will be performed to determine the distribution of heavy metals and species under set conditions from previous devolatilization experiments. The equilibrium calculations will serve as a useful tool for prior estimation of the distribution of heavy metals. The impact of different liquors on volatilization of heavy metals in the experiments will be determined. The char residue and condensation aerosol (fume) particles from each experiment will be analyzed using ICP-AES. The amount of heavy metals volatilization during combustion and gasification will be determined based on the amount of the metals in the char residues and fume particles.
Based on the results of the experimental study combined with data from the equilibrium analysis program the main cause of variability in heavy metal vaporization can be found. Also the boiler operating conditions can be studied to determine its affects on the volatility of the heavy metals.
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Mao, Tie. „Impact of liquid droplets on solid surfaces and its applications to carryover deposition in kraft recovery boilers“. Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ28008.pdf.
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Walsh, Allan R. „A computer model for in-flight black liquor combustion in a kraft recovery furnace“. Diss., Georgia Institute of Technology, 1989. http://hdl.handle.net/1853/7060.
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Ebrahimi-Sabet, Seyed Abdolreza. „A laboratory study of deposit removal by debonding and its application to fireside deposits in kraft recovery boilers“. Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/NQ58923.pdf.
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Khan, Aamna [Verfasser], Oliver [Akademischer Betreuer] Boine-Frankenheim und Kurt [Akademischer Betreuer] Aulenbacher. „Space Charge Effects in Energy Recovery Linacs / Aamna Khan ; Oliver Boine-Frankenheim, Kurt Aulenbacher“. Darmstadt : Universitäts- und Landesbibliothek Darmstadt, 2020. http://d-nb.info/1202923003/34.
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Khan, Aamna [Verfasser], Oliver Akademischer Betreuer] Boine-Frankenheim und Kurt [Akademischer Betreuer] [Aulenbacher. „Space Charge Effects in Energy Recovery Linacs / Aamna Khan ; Oliver Boine-Frankenheim, Kurt Aulenbacher“. Darmstadt : Universitäts- und Landesbibliothek Darmstadt, 2020. http://d-nb.info/1202923003/34.
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Chandra, Yusup. „Alkaline pulping deadload reduction studies in chemical recovery system /“. Thesis, Available online, Georgia Institute of Technology, 2004:, 2004. http://etd.gatech.edu/theses/available/etd-11162004-132752/unrestricted/Chandra%5FYusup%5F200412%5Fmast.pdf.
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Thesis (M.S.)--Chemical Engineering, Georgia Institute of Technology, 2005.Empie, Jeff, Committee Chair ; Banerjee, Sujit, Committee Member ; Deng, Yulin, Committee Member. Includes bibliographical references.
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Rezaie, Navaie Ali [Verfasser], George [Akademischer Betreuer] Tsatsaronis, George [Gutachter] Tsatsaronis und Udo [Gutachter] Hellwig. „Thermal design and optimization of heat recovery steam generators and waste heat boilers / Ali Rezaie Navaie ; Gutachter: George Tsatsaronis, Udo Hellwig ; Betreuer: George Tsatsaronis“. Berlin : Technische Universität Berlin, 2017. http://d-nb.info/1156187052/34.
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Sosa, Ivan Raul Herrera. „Sistemas multiagentes para controle inteligente da caldeira de recuperação“. Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/3/3137/tde-08012008-110219/.
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Engenheiros têm introduzido um melhor suporte para procedimentos de monitoramento de condições complexas através da aplicação de sistemas descentralizados inteligentes usando uma variedade de técnicas de inteligência artificial. Agora é largamente reconhecido que estes problemas decorrentes da complexidade funcional do monitoramento de condições podem ser resolvidos com arquiteturas que contenham muitos módulos distribuídos e inteligentes, que interajam dinamicamente, os quais são chamados de agentes inteligentes. A tecnologia baseada em agentes tem gerado muita agitação nos últimos anos por causa da promessa de ser um novo paradigma na hora de definir os conceitos para modelar e implementar sistemas de controle. O objetivo do presente estudo é implantar esta tecnologia no controle de uma caldeira de recuperação com a finalidade de gerenciar e integrar produção, qualidade e segurança no processo. A caldeira de recuperação tem dois objetivos bem definidos, cada um com suas restrições operacionais: (1) geração de vapor vivo a ser utilizado no processo, e, (2) redução de reagentes inorgânicos para recuperar sulfeto e carbonato de sódio, necessários no ciclo do processo de fabricação de celulose. Cada um destes objetivos é um sistema com funções independentes dentro da caldeira, mas que, no entanto tem seus desempenhos interligados entre si através das variáveis comuns existentes no processo. Esta é exatamente a definição de um sistema agente, ou melhor, de um Sistema Multi-Agente (SMA), no qual não existe uma otimização e sim a busca de uma solução possível. O modelo dinâmico da Caldeira foi simulado em Matlab(TM) Simulink(TM) baseado no modelo matemático da caldeira de recuperação de licor negro B&W (Babcock&Wilcox). O SMA foi desenvolvido utilizando a linguagem de programação JAVA e a plataforma de agentes JADE.Engineers have been introducing better support for procedures of monitoring complex conditions through the application of intelligent decentralized systems, implementing a variety of artificial intelligent techniques. Nowadays it is vastly known that these problems that are consequence of the functional complexity of monitoring conditioning can be solved trough architectures, built by many intelligent distributed modules, which interact dynamically, known as intelligent agents. Technology based on agents have been creating excitement over the last years because of its promise of being a new paradigm that can be used to define modeling and implementing concepts for control systems. The goal of this thesis is to implement this new technology on controlling a recovery boiler, aiming to manage and integrate production, quality and security to the process. The operation of the recovery boiler has two well defined objectives, each one with its operational constraints: (1) steam production, an important asset in the pulp and paper process, and, (2) reduction of inorganic reagents to recover sulfate and sodium carbonates, the necessary chemicals in the Kraft pulp production. Each one of these functions, is an independent system inside the recovery boiler, however they have their performances connected to each other by common variables present in the process. This is exactly the definition of an agent system, in other words, a definition of a Multi-Agent System (MAS), for which there is not an optimization, but the search for the best possible outcome. The recovery boiler dynamic model was simulated using Matlab(TM) Simulink(TM) based on the mathematic model of B&W (Babcock&Wilcox) recovery boiler of black liquor. The MAS was implemented using JAVA(TM) programming language and JADE(TM) agent platform.
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Almeida, Gustavo Matheus de. „Detecção de situações anormais em caldeiras de recuperação química“. Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/3/3137/tde-01122006-155750/.
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O desafio para a área de monitoramento de processos, em indústrias químicas, ainda é a etapa de detecção, com a necessidade de desenvolvimento de sistemas confiáveis. Pode-se resumir que um sistema é confiável, ao ser capaz de detectar as situações anormais, de modo precoce, e, ao mesmo tempo, de minimizar a geração de alarmes falsos. Ao se ter um sistema confiável, pode-se empregá-lo para auxiliar o operador, de fábricas, no processo de tomada de decisões. O objetivo deste estudo é apresentar uma metodologia, baseada na técnica, modelo oculto de Markov (HMM, acrônimo de ?Hidden Markov Model?), para se detectar situações anormais em caldeiras de recuperação química. As aplicações de maior sucesso de HMM são na área de reconhecimento de fala. Pode-se citar como aspectos positivos: o raciocínio probabilístico, a modelagem explícita, e a identificação a partir de dados históricos. Fez-se duas aplicações. O primeiro estudo de caso é no ?benchmark? de um sistema de evaporação múltiplo efeito de uma fábrica de produção de açúcar. Identificou-se um HMM, característico de operação normal, para se detectar cinco situações anormais no atuador responsável por regular o fluxo de xarope de açúcar para o primeiro evaporador. A detecção, para as três situações abruptas, é imediata, uma vez que o HMM foi capaz de detectar alterações, abruptas, no sinal da variável monitorada. Em relação às duas situações incipientes, foi possível detectá-las ainda em estágio inicial; ao ser o valor de f (vetor responsável por representar a intensidade de um evento anormal, com o tempo), no instante da detecção, próximo a zero, igual a 2,8% e 2,1%, respectivamente. O segundo estudo de caso é em uma caldeira de recuperação química, de uma fábrica de produção de celulose, no Brasil. O objetivo é monitorar o acúmulo de depósitos de cinzas sobre os equipamentos da sessão de transferência de calor convectivo, através de medições de perda de carga. Este é um dos principais desafios para se aumentar a eficiência operacional deste equipamento. Após a identificação de um HMM característico de perda de carga alta, pôde-se verificar a sua capacidade de informar o estado atual e, por consequência, a tendência do sistema, de modo similar à um preditor. Pôde-se demonstrar também a utilidade de se definir limites de controle, com o objetivo de se ter a informação sobre a distância entre o estado atual e os níveis de alarme de perda de carga.The greatest challenge faced by the area of process monitoring in chemical industries still resides in the fault detection task, which aims at developing reliable systems. One may say that a system is reliable if it is able to perform early fault detection and, at the same time, to reduce the generation of false alarms. Once there is a reliable system available, it can be employed to help operators, in factories, in the decisionmaking process. The aim of this study is presenting a methodology, based on the Hidden Markov Model (HMM) technique, suggesting its use in the detection of abnormal situations in chemical recovery boilers. The most successful applications of HMM are in the area of speech recognition. Some of its advantages are: probabilistic reasoning, explicit modeling and the identification based on process history data. This study discusses two applications. The first one is on a benchmark of a multiple evaporation system in a sugar factory. A HMM representative of the normal operation was identified, in order to detect five abnormal situations at the actuator responsible for controlling the syrup flow to the first evaporator. The detection result for the three abrupt situations was immediate, since the HMM was capable of detecting the statistical changes on the signal of the monitored variable as soon as they occurred. Regarding to the two incipient situations, the detection was done at an early stage. For both events, the value of vector f (responsible for representing the strength of an abnormal event over time), at the time it occurred, was near zero, equal to 2.8 and 2.1%, respectively. The second case study deals with the application of HMM in a chemical recovery boiler, belonging to a cellulose mill, in Brazil. The aim is monitoring the accumulation of ash deposits over the equipments of the convective heat transfer section, through pressure drop measures. This is one of the main challenges to be overcome nowadays, bearing in mind the interest that exists in increasing the operational efficiency of this equipment. Initially, a HMM for high values of pressure drop was identified. With this model, it was possible to check its capacity to inform the current state, and consequently, the tendency of the system (similarly as a predictor). It was also possible to show the utility of defining control limits, in order to inform the operator the relative distance between the current state of the system and the alarm levels of pressure drop.
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Emami, Babak. „Numerical Simulation of Kraft Recovery Boiler Sootblower Jets“. Thesis, 2009. http://hdl.handle.net/1807/19028.
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The fouling of heat transfer surfaces in kraft recovery boilers is a significant concern for the pulp and paper industry. The usual approach to controlling fouling is the use of so-called ``sootblowers,'' that utilize boiler steam to generate supersonic steam jets that are literally used to knock deposits off of the boiler tubes. About 3 to 10\% of the total steam produced in a recovery boiler is used for sootblowing. This high energy cost demands that they be operated as efficiently as possible. It is thus essential to devise improved strategies for maximizing sootblower efficiency and minimizing steam consumption. To achieve this, the behaviour of sootblower jets, and the effects of various parameters on sootblowing, must be well understood.
This thesis documents a study of the performance of sootblower jets using numerical simulation; CFDLib 3.02, a CFD code from the Los Alamos National Laboratory, was used for the simulations. This work had two main parts. In the first part, sootblower jets that perform at the design condition (fully-expanded jets) were studied; in the second part, the study was extended to off-design (under/over-expanded) sootblower jets.
In the first part, a compressibility-corrected version of CFDLib was validated against a wide range of available experimental data, of subsonic and fully-expanded supersonic free and impinging jets; simulations successfully predicted all of the cases. This compressibility-corrected model was then deemed suitable for modeling the fluid mechanics of fully-expanded sootblower jets, and so was used to study the effects of two parameters on sootblower jets: the lance pressure, and the rate of rotation of a sootblower. To study the effect of the lance pressure, numerical simulation was used to model fully-expanded sootblower jets corresponding to a range of lance pressures. To study the effect of rotation, the equations of motion were modified by adding the Coriolis and centrifugal terms, so that computations could be performed in a rotating frame of reference. Simulations were then run to study a fully-expanded sootblower jet operating at different rotation rates. The results indicate that sootblowers operate more efficiently at lower lance pressures, and that the rate of rotation does not significantly affect the structure of a sootblower jet.
In the second part, the study was extended to sootblower jets not operating at the design condition. The compressibility-corrected code failed to properly simulate these under-over/expanded supersonic jets. A wide series of tests was carried out to determine that the problem was due to the turbulence model. The model was then modified to account for turbulence/shock wave interaction, by adding corrections to take into account shock unsteadiness and a realizability constraint. The new model yielded good agreement with some available measurements. The new model was then used to successfully predict some actual sootblower measurements, and to study the interaction of a sootblower jet with geometries similar to tube banks in recovery boilers. A parametric study was carried out to examine the effect of the offset between a sootblower jet and a tube bank, and of deposit size on a sootblower jet. The results indicate that the shock cell structure of a jet is only slightly affected by the offset, but that the size of a deposit strongly affects the pressure exerted by the impinging sootblower jet, which depends both on the jet shock cell structure, and on the location where the interaction occurs.
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Saturnino, Daniel Moreira. „The solubility of kraft recovery boiler precipitator ash“. 2006. http://link.library.utoronto.ca/eir/EIRdetail.cfm?Resources__ID=450312&T=F.
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Ketler, Stephen Paul. „Physical flow modelling of a kraft recovery boiler“. Thesis, 1993. http://hdl.handle.net/2429/4889.
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Measurements of the vertical, and one horizontal, components of velocity have been made in
an isothermal scale model of a kraft black liquor recovery boiler. The model used water as the
working fluid, and was a 1:28 scale representation of an operating recovery boiler in Plymouth,
North Carolina. All of the air ports were represented in the model; however, the char bed shape,
mass flow from the bed, and liquor flow were not. Laser-Doppler velocimetry was used to measure
velocities and power spectral densities in the model on a 6x6 grid of points on three horizontal
planes. Quantitative flow visualization was performed using laser sheet illumination of particles in
the flow, with subsequent analysis of the particle images.
Flow conditions simulating industrial arrangements and special configurations were run in
the model. Industrial configurations employed flows from primary, starting burner, secondary, and
either concentric load-burner or interlaced tertiary ports. Special configurations using only primary
and secondary port flows were tested to investigate the sensitivity of the flowfield to variations in the
lower furnace port flows. Orifice-plate flowmeters and valves were used to set the flowrates through
manifolds connected to groups of ports. The error between the set and actual model total flowrate
was shown to be dependent on the choice of flowmeters, and on the drift of valve settings with time.
Considering both sources of error, for a typical model flowrate of 150 US gallons per minute, the
expected difference between the set and actual total flowrate was —6.5 percent. Differences between
the set mass flows, and the values calculated from the vertical velocities measured by the laser
Doppler velocimeter, were less than ten percent on average. Larger variances between measured and
predicted mass flows were explained on the basis of observed low frequency oscillations.
Computer software was created for the computation of velocity power spectral densities
using the output of the laser-Doppler velocimeter. A system of digital particle image velocimetry was
also created for quantitative two-dimensional flow visualization. Laser light was spread into a planar
sheet, and the motion of small polystyrene particles added to the flow was recorded on videotape at
30 frames per second. The information on the videotape was digitized, and cross-correlation analysis
of successive image pairs yielded a
grid of velocity vectors for each 1/30 second interval which could
be animated.
It was found that the flow in the model was extremely sensitive to any asymmetries in the
secondary level port flows. An increase in secondary flow velocity of 10% on one wall, and a
corresponding decrease on the opposite wall, caused the core region of vertical upflow at the liquor
gun level to occupy half of the model cross section near the wali with the lower velocity. It was very
difficult to balance the flows accurately enough to have the core region of vertical upflow in the
model centre. In the upper regions of the furnace, the majority of the upflow was near the walls,
with down or stagnant flow in the model centre. The flow exhibited low frequency unsteadiness in
addition to a high level of turbulence throughout. Periods on an order of 10-20 seconds were
observed in the velocity power spectral densities, and in the particle image velocimetry results.
The use of concentric load-burner port flows on the tertiary level, as opposed to a 2x2
interlaced arrangement of high velocity tertiary ports, was found to provide a somewhat more
uniform distribution of turbulence kinetic energy in the upper furnace. Implications for design and
operation of industrial recovery boilers are discussed.
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Taranenko, Anton. „Shattering Kraft Recovery Boiler Smelt by a Steam Jet“. Thesis, 2013. http://hdl.handle.net/1807/35142.
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Kraft recovery boiler smelt is shattered into small droplets by an impinging steam jet to prevent smelt-water explosions in the dissolving tank. Inadequate shattering increases the likelihood of dissolving tank explosions. While industry has not dedicated much effort to smelt shattering, the safety implications require smelt shattering to be studied in detail. An experimental set-up was constructed to simulate the shattering operation using a water-glycerine solution and air instead of smelt and steam respectively. The objective was to examine how physical properties and flow characteristics affect shattering. It was
found that increasing shatter jet velocity greatly reduced droplet mean diameter.
Increasing the liquid flow rate greatly increased droplet size, as expected. Shattering was not significantly affected by viscosity, unless a weak shatter jet was used on a highly viscous fluid. Increasing the proximity of the shatter jet nozzle decreased droplet size.
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Sretenovic, Ivan. „Factors Affecting the Resistivity of Recovery Boiler Precipitator Ash“. Thesis, 2012. http://hdl.handle.net/1807/32628.
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Electrostatic precipitators (ESPs) are commonly used to control particulate emissions from recovery boilers in the kraft pulping process. The electrical resistivity of entrained particulates is known to affect the performance of ESPs. There are many factors which influence resistivity of particulate matter, such as field strength, time of exposure, particle size, particle composition, temperature, and flue gas composition. The objective of this study was to identify the ideal operating conditions and dust particle characteristics which lead to an optimum dust resistivity and maximized ESP efficiency. The effect of these factors was examined through a variety of experimental and analytical techniques on kraft recovery boiler ash samples and synthetically prepared samples. It was concluded that particle composition, gas composition, and ambient temperature had the most pronounced effects, while the other factors, such as field strength and exposure time, had a smaller impact on particle resistivity.
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Guo, Ci-Sen, und 郭騏森. „Recovery and treatment of boiler-washing wastewater containing EDTA“. Thesis, 2011. http://ndltd.ncl.edu.tw/handle/38282592745769587544.
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碩士崑山科技大學
環境工程研究所
99
This article is focused on the physicochemical treatment and EDTA recycling of sewage containing EDTA from furnace washing. Testing revealed the COD concentration of sewage was 31,000 mg/L, and AA quantitative analysis for metal ions showed that the iron (Fe) species were the most abundant constituents (1,950 mg/L), followed by zinc (Zn, 230 mg/L), copper (Cu, 93 mg/L) and other metal ions in smaller amounts. Metal deposition, EDTA recycling, oxidative decomposition and activated carbon absorption were applied in the experiment. Sodium chloride was added to promote the deposition of metal ions. The dry weight of the metal-containing deposit was 5.4 g/L. After treatment, the amount of iron species decreased from 1,950 mg/L to 3 mg/L. The recycling of EDTA was achieved by adding sulfuric acid, which converts disodium EDTA into EDTA-4H and can be easily recycled. Post-treatment COD concentration was 11,300 mg/L. By incorporating oxidative decomposition and activated carbon absorption, COD concentration can be decreased to 1,780 mg/L. The use of RO filtration technique may shorten the time for sewage processing.
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Boonsongsup, Lerssak. „SO��� capture and HCl release at Kraft recovery boiler conditions“. Thesis, 1993. http://hdl.handle.net/1957/35778.
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Liu, Kao-Teng, und 劉高登. „The recovery and treatment of wastewater for cleaning boiler scale“. Thesis, 2010. http://ndltd.ncl.edu.tw/handle/52105406118140118844.
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碩士崑山科技大學
環境工程研究所
98
High concentration of EDTA is hard to be degraded biologically, this paper research the phsiochemical recovery and treatment of the scale-cleaning wastewater containing EDTA from boiler. The water investigation showed that the COD and EDTA concentration in the original wastewater was as high as 48700 and 47695 mg/L，while the major metal contents of Fe, Zn, Cu were 1946, 232.8 and 93.1 mg/L respectively. The experimental process included chemical precipitation, crystallization, oxidization, and final activated carbon adsorption for the residual COD. The addition of sodium hydroxide, but not the hydrogen sulfide and sodium phosphate, was the best agent for chemical metal precipitation that resulted in the residual Fe contents decreased to 3 mg/L in the wastewater. The crystallization process recovered EDTA from the wastewater high than 72.3 percentage, and it was approved that the crystals contained 99.88 % of EDTA and the residual COD in the wastewater was declined to 13500 mg/L。The further oxidation treatment using hydrogen peroxide solution for 72 hours degraded EDTA in the results of EDTA concentration of 618 mg/L, but still left COD of 12016 mg/L in the wastewater. It indicated that the hydrogen peroxide degraded the EDTA structure partly but not removed COD. However, the final activated carbon adsorption for 24 hours did reduced the residual COD from 12016 to 310 mg/L. Thus, 99.4 % of the total COD in the original wastewater was removed in the whole treatment process. The recovery and treatment process needed 6~7 duration days, and consumed alkaline and acid for the industrial grade in the cost of about 400 NT dollars, the hydrogen peroxide and activated carbon for 15000 NT dollars, while recovered EDTA in the value of 2600 NT dollars per cubic metric wastewater. It was suggested that process for more time shorter and cost economical was needed to develop in the future.
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Tan, Geng. „Mechanisms of accelerated recovery boiler char bed cooling with sodium bicarbonate“. 2005. http://link.library.utoronto.ca/eir/EIRdetail.cfm?Resources__ID=232665&T=F.
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Gonçalves, Cláudia R. de Souza. „Factors affecting chloride and potassium removal from recovery boiler precipitator ash by leaching“. 2005. http://link.library.utoronto.ca/eir/EIRdetail.cfm?Resources__ID=370094&T=F.
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