The aim of this thesis is design a hotwater boiler for burning natural gas with an output of 60 MW. Boiler works with temperature difference 150 °C / 70 °C. For a given fuel is calculated stoichiometric calculation. The following is the calculation of the heat balance of the boiler including the determinativ of thermal efficiency. The fuel used, the required parameters of hot water and feed water temperature are designed individual convective surfaces and dimensions of the boiler. The boiler design includes drawings.

The thesis is dedicated to the design of the steam boiler which burns wood chips, with a natural circulation of the water. It is a grate boiler, which produces 20 t/h of the steam. The output parameters of the steam are 420 °C and 5 MPa. The feedwater temperature is 125 ° C .The thesis gradually deals with stoichiometric calculations and determines the efficiency of the boiler. Then it describes the design of the fireplace and thermal calculations of each heat transfer surfaces. The appendix includes drawings of the boiler.

The aim of the work is the design of a grate boiler of 200 t . h-1 output, which will burn brown coal or wood chips. The work is divided into several parts. First, stoichiometric calculation and the calculations enthalpy of flue gases and air are performed. After calculating the heat balance and loss of the boiler was counted boiler efficiency. The design of individual heating surfaces is proposed and at the end are controlled the overall heat balance of the boiler. The calculation is supplemented by drawings.

The aim of the master’s thesis is thermal calculation and dimensional design of boiler of 235 t/h which burns brown coal. The work is divided into several parts. In the first part, stoichiometric calculation and the calculations enthalpy of flue gases and air are performed. After calculating the heat balance and loss of the boiler, the boiler efficiency is counted. In the next part, thermal calculation of combustion chamber is calculated. Subsequently, design of the individual heating surfaces is proposed. Finally, the overall heat balance of the boiler is inspected. The calculation is supplemented by drawing of the boiler.

This thesis is focused on design of black coal combustion boiler of 160t/h output. It consists of several parts. First, stechiometric calculations and enthalpy of air and gas are made, then heat balance of boiler and the boiler losses are calculated, and also thermal efficiency is determined. In next step, the combustion chamber is designed and its thermal calculation is made. Then, each of heating surfaces are designed, and in the last step overall energy balance of the boiler is checked. The scheme of pressure system and design documentation added.

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.

The EU waste hierarchy includes energy recovery facilities where waste is used as fuel in combined heat- and powerplants. When waste is incinerated can the thermal energy be used in for example, district heating networks and or electricity generation. The purpose of the degree project is to make a pre-study of Heat Management's system solution HISS, optimization of steam soot blowing at Mälarenergi's waste boiler. Waste is a heterogeneous fuel that typically contains a variety of substances such as alkali, chlorine and heavy metals that often contribute to fouling on heat transfer surfaces. These coatings reduce the efficiency of heat transferring surfaces such as superheaters. Cleaning by soot blowing using steam is done at regular intervals to maintain efficiency. Superheater cleaning on the Block 6 is done by retractable rotating soot blowers equipped with a nozzle from where steam is sprayed out at pressure of 25 bar. The blowers are inserted one at a time in a sequence, which means that they wait for the previous blower before the next one can enter. Steam is taken from the main process, which leads to reduction in load on the turbine and causes wear during the sweeping process due to the high impact force. This can lead to erosive damage and thinning of the material on the tubes, thus shortening the lifespan of the superheaters. The optimisation adjusts the soot sequence so that full steam pressure is used only in one direction of travel of the lance, this allows an overlapping soot sequence to be used and thus halves the time required for sooting. Analysis of shorter sooting time and reduced steam consumption based on production data and case studies has led to the following results. The energy consumption of the auxiliary power is reduced by 14.25 MWh per sweeping sequence and 7 115.5 MWh annually. The turbine can produce 2.51 MWh more electricity per sweeping as the time it runs at reduced load is reduced, totalling 1 254.39 MWh in one year. 24.03 tonnes of steam are saved per sweeping and 12 003 tonnes in one year. Payback time for the optimisation is 1.01 years based on an average spot price from Mälarenergi's budgeting from last year. Considering current electricity prices could the payback time be further reduced. The conclusion from the pre-study is that the optimisation as the investment is economically viable and has other positive benefits such as: steadier steam flow and reduced pressure surges. Wear and tear on superheaters are reduced as they are only sprayed with high pressure once instead of twice per sweeping sequence. / I EU:s avfallshierarki ingår energiåtervinningsanläggningar där avfall används som bränsle i förbränningsanläggningar. Vid förbränning utav avfall så kan den utvunna termiska energin användas exempelvis i fjärrvärmenät och- eller generering utav el. Examensarbetets syfte är att göra en förstudie på Heat managements systemlösning HISS, optimering utav ångsotning på Block 6 som är Mälarenergis avfallspanna. Avfall är ett heterogent bränsle som typiskt innehåller en mängd olika ämnen som alkali, klor och tungmetaller som ofta bidrar till att beläggningar bildas på värmeöverförningsytor. Dessa beläggningar försämrar ytors värmeöverförningsverkningsgrad på till exempel överhettare. Rengöring i form av ångsotning görs i jämna intervall för att hålla verkningsgraden uppe. Sotning av överhettare på Block 6 skes av en utdragbar, roterande sotlans utrustad med en dysa där ånga sprutas ut med 25 bars tryck. Lansarna körs in en åt gången i en sekvens vilket innebär att dem väntar på föregående lans innan nästa kan köras. Ångan som används tas från huvudprocessen vilket medför reducerad last på turbinen och dessutom uppstår slitage vid sotningen ty den höga anslagskraften. Detta kan leda till erosiva skador och förtunning utav godset på tuberna och således förkortas livslängden på överhettarna. Optimeringen justerar sot sekvensen så att fullt ångtryck används bara i ena färdriktningen av lansen, detta möjliggör att en överlappande sotsekvens kan användas och på så vis halveras tidsåtgången för sotningen. Analysen utav kortare sottidsåtgång samt minskad ångförbrukning baserat på produktionsdata hämtad från styrsystemet 800xA samt fallstudier har mynnat ut i följande resultat. Hjälpkraftens energianvändning minskas med 14,25 MWh per sotningssekvens och årligen 7 115,5 MWh. Turbinen kan producera 2,51 MWh mer el vid varje sotning då tiden som den körs med reducerad last blir kortare, totalt på ett år blir det 1 254,39 MWh. Vid varje sotning sparas 24,03 ton ånga och på ett år 12 003 ton. Återbetalningstiden för optimeringen blir 1,01 år baserat på ett medelspotpris från Mälarenergis budgetering från förra året. Med hänsyn till dagens elpriser förkortas återbetalningstiden ytterligare.   Förstudien rekommenderar optimeringen då dels är investeringen lönsam rent ekonomiskt, dels medför den andra positiva fördelar. Optimeringen med överlappande sotning skapar ett jämnare ångflöde, det reducerar tryckstötar som är skadliga. Slitage på överhettartuber minskas då dem bara besprutas med högt tryck en gång i stället för två gånger per sotningssekvens. Behovsstyrd sotning skulle kunna implementeras upp till 3 gånger per dygn utan att det skulle kosta mer mot dagsläget där man stora 1,5 gånger per dygn.

<p>All products will eventually end up as waste, which in a sustainable society has to be handled in an efficient and environment friendly way. This report focuses on waste fractions meant for combustion, often difficult to characterize. However, more homogeneous fractions that are treated biologically are also discussed.</p><p>The study concerns the region of Borås, Sweden, where the waste plant Sobacken has provided a good starting point. On this site, fuel to the Energy-from-Waste plant of Borås Energi is prepared and the biological waste is treated through anaerobic digestion.</p><p>One important part of the study has been to collect experience-based knowledge from the technical staff at Sobacken and Borås Energi. This information was compiled into an overview of wanted and unwanted fractions to the preparation plant and the boilers respectively. The purpose of this overview is to complement existing delivery terms and thereby facilitate an increased quality of the fuel from the suppliers.</p><p>A significant element of the analysis has been to characterize the content of the industrial waste sent to Sobacken for combustion. Chemical analyses of the prepared fuel as well as the conducted waste component analysis indicate a heterogeneous composition of the waste. A heterogeneous fuel often results in an uneven combustion, leading to higher emissions and an unwanted variation in the energy production.</p><p>Through the waste component analysis, a comprehensive picture of the waste composition was attained. Materials non-valid for delivery mostly consisted of wet domestic waste (biodegradable materials), but some hazardous waste was also found. The results of the waste component analysis were communicated to the involved suppliers and this has already resulted in a considerable reduction of the amount of biodegradable waste in the deliveries of industrial waste.</p> / <p>Förr eller senare blir alla produkter avfall, som i ett uthålligt samhälle måste hanteras på ett resurssnålt och miljövänligt sätt. Det här arbetet är främst inriktat mot de svåridentifierade fraktionerna som är ämnade för förbränning, men berör även de mer homogena fraktionerna som behandlas biologiskt genom rötning.</p><p>Arbetet har utförts i Boråsregionen där Sobackens avfallsanläggning, med beredning av avfallsbränsle till Borås Energis två FB-pannor och rötkammare, har utgjort en naturlig utgångspunkt.</p><p>Ett stort inslag i arbetet var sammanställning av erfarenhetsbaserade kunskaper hos driftteknikerna på beredningsanläggningen, liksom hos Anders Johnsson på Borås Energi. På detta sätt erhölls viktig information om både bra och dåliga fraktioner, för såväl avfallskross som för pannor. Dessa fakta har bland annat använts för att sätta samman en översikt över önskade respektive oönskade fraktioner. Översikten är tänkt som komplement till befintliga leveransregler, i syfte att förenkla för avfallsleverantörerna.</p><p>Stor vikt har lagts vid att försöka kartlägga sammansättningen av det verksamhetsavfall som kommer in till Sobackens beredningsanläggning. Både kemiska analyser av bränsleprov och utförd plockanalys visar på en heterogen sammansättning i avfallet. Ett heterogent bränsle brinner i många fall ojämt, vilket resulterar i högre emissionsnivåer samt en icke-önskvärd variation i energiproduktion.</p><p>I och med plockanalysen erhölls en övergripande bild av förbränningsavfallets sammansättning. Det icke leveransgilla materialet som påträffades utgjordes främst av blött hushållsavfall (biologiskt nedbrytbart material), men även av en del elektronik påträffades. Efter avslutad analys kommunicerades erhållna resultat med aktuella leverantörer, vilket hittills har resulterat i en betydande minskning av biologiskt nedbrytbart material i verksamhetsavfallet.</p>

Orientador: Ricardo Alan Verdú Ramos / Resumo: Este trabalho apresenta uma alternativa para a utilização do lodo gerado em estação de tratamento de efluentes de uma indústria de celulose sul mato-grossense, mais especificamente para a queima em caldeira de leito fluidizado borbulhante, misturado com biomassa de madeira, minimizando a quantidade e o custo de seu envio para aterro industrial. As caracterizações físico-químicas dos lodos e cinzas, em amostras pontuais, foram analisadas por laboratório acreditado pela ABNT, seguindo os critérios da NBR 10.004:2004, sendo que os resultados comprovaram que tais resíduos se enquadram dentro da norma como de Classe IIA. As emissões atmosféricas também foram analisadas, por laboratório credenciado, seguindo os critérios da resolução CONAMA 316/2002, tendo sido observado que as quantidades de material particulado, óxidos de enxofre, óxidos de nitrogênio, ácido clorídrico, cloro livre, fluoretos, metais, cianeto, dioxinas e furanos, atendem aos limites legais previstos na referida resolução. Instrumentos instalados na chaminé da caldeira de biomassa, monitoraram as emissões atmosféricas referentes à material particulado, óxidos de nitrogênio, óxidos de enxofre e monóxido de carbono, em todo o período operacional da caldeira. O período considerado para estudo foi de Janeiro/2017 a Julho/2018, o qual envolve o início da operação de uma nova linha de produção de celulose, elevando a capacidade produtiva de vapor da caldeira de biomassa, de 120 para 150 t/h de vapor, e a produção de cel... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This work presents an alternative for the use of sludge generated in a wastewater treatment plant of a Mato Grosso do Sul pulp industry, more specifically for burning in a bubbling fluidized bed boiler mixed with wood biomass, minimizing the amount and the shipping cost to industrial landfill. The physicochemical characterization of sludge and ash in point samples were analyzed by an external laboratory accredited by ABNT, following the criteria of NBR 10.004:2004, and the results showed that such residues fall within the standard as Class IIA. Atmospheric emissions were also analyzed by an accredited laboratory following the criteria of CONAMA Resolution 316/2002, and it was observed that the amounts of particulate matter, sulfur oxides, nitrogen oxides, hydrochloric acid, free chlorine, fluorides, metals, cyanide dioxins and furans meet the legal limits laid down in that resolution. Instruments installed in the biomass boiler chimney monitored atmospheric emissions from particulate matter, nitrogen oxides, sulfur oxides and carbon monoxide throughout the boiler operating period. The period considered in this study was January/2017 to July/2018 that involves the start of operation of a new pulp production line, increasing the production capacity of the biomass boiler steam from 120 to 150 t/h of steam, and pulp production from 1,275 to 3,200 million tons per year. Based on data for this period some significant changes could be noted by comparing the situations before and aft... (Complete abstract click electronic access below) / Mestre

Heat recovery steam generators (HRSG) play a very important role in combined cycle (CC) power plants, where steam is generated from a gas turbine exhaust and supplied at the appropriate pressure and temperature to steam turbines for further power generation. The power plants achieve an overall efficiency above 55% and are ideally suited for combined heat and power generation in utility systems. The performance of energy conversion is improved by reducing exergy losses which implies reducing the temperature difference between the combustion gas and the steam cycle. Thus recent HRSG designs include up to three pressure levels with reheat in the steam cycle for maximum energy recovery and the use of high pressure, high temperature superheater and reheater in CC plants. Super critical boilers are also conceivable. Since HRSG performance has a large impact on the overall efficiency of the CC power plant, an accurate simulation of the performance of the HRSG is necessary. We present a steady state HRSG model to support design and rating simulations of vertical units. The simulation model, called FELVAL, divides the boiler in its rows. The row model can also be divided several times following the tube length, to better estimate the fumes temperature distribution across the hot gas path. Another model, called SUFVAL, carries out the design as well as the automatic generation of the FELVAL units and all the needed connections. The log mean temperature difference (LMTD) method and the effectiveness-NTU (ε -NTU) method are alternatively used to compute the overall heat transferred in each part of the HRSG. The problem of convergence of boiler models with more than one row in parallel is discussed. Good initialisation of the different variables is crucial to obtain convergence. The models are tested on 2 references HRSG. The first one is an assisted circulation boiler that operates at 3 subcritical pressure levels. The second is a once through boiler able to operate above the critical pressure of water. These new models were introduced into a commercial software of data reconciliation (VALI of Belsim sa) already used by the engineering and design departments of a HRSG manufacturer. They thus have a general-purpose package enabling them to make design, data reconciliation and simulation with the same software. Moreover, the use of FELVAL model will enable them to simulate any type of boiler and to obtain informations on the change of the temperatures inside the heat exchangers. This information is crucial for well monitoring closely the operation of a boiler, and better understanding its behaviour. This knowledge improvement allows to limit the overdesign and the safety margins and to reduce the investment costs.