This diploma thesis describes the design of steam boiler for combustion natural gas, which has a steam power 80t/hour. In the first phase is performed calculation of stoichiometric amount of combustion air and flue gas. After that follows constructional proposal of the combustion chamber. Furthermore continue by calculation heating surfaces of the boiler. In conclusion, the thesis is focused on designing the injections. To check the accuracy of the results is recalculated heat balance the whole boiler.

Water temperature is a critical factor for the quality and biological condition of streams. Among various factors affecting stream water temperature, air temperature is one of the most important factors related to water temperature. To appropriately quantify the relationship between water and air temperatures over a large geographic region, it is important to accommodate the spatial and temporal information of the steam temperature. In this dissertation, I devote effort to several statistical modeling techniques for analyzing bivariate spatial-temporal data in a stream temperature study. In the first part, I focus our analysis on the individual stream. A time varying coefficient model (VCM) is used to study the relationship between air temperature and water temperature for each stream. The time varying coefficient model enables dynamic modeling of the relationship, and therefore can be used to enhance the understanding of water and air temperature relationships. The proposed model is applied to 10 streams in Maryland, West Virginia, Virginia, North Carolina and Georgia using daily maximum temperatures. The VCM approach increases the prediction accuracy by more than 50% compared to the simple linear regression model and the nonlinear logistic model. The VCM that describes the relationship between water and air temperatures for each stream is represented by slope and intercept curves from the fitted model. In the second part, I consider water and air temperatures for different streams that are spatial correlated. I focus on clustering multiple streams by using intercept and slope curves estimated from the VCM. Spatial information is incorporated to make clustering results geographically meaningful. I further propose a weighted distance as a dissimilarity measure for streams, which provides a flexible framework to interpret the clustering results under different weights. Real data analysis shows that streams in same cluster share similar geographic features such as solar radiation, percent forest and elevation. In the third part, I develop a spatial-temporal VCM (STVCM) to deal with missing data. The STVCM takes both spatial and temporal variation of water temperature into account. I develop a novel estimation method that emphasizes the time effect and treats the space effect as a varying coefficient for the time effect. A simulation study shows that the performance of the STVCM on missing data imputation is better than several existing methods such as the neural network and the Gaussian process. The STVCM is also applied to all 156 streams in this study to obtain a complete data record. / Ph. D.

Pappers- och massaindustrin är stor i Sverige och dess produkter konsumeras vid hög grad. Eftersom industrin är omfattande och energikrävande är det viktigt att energianvändningen kan optimeras så långt som möjligt. I detta examensarbete utförs en utredning gällande en sodapanna och dess utgående ångtemperatur.  Sodapannan tillhör Mondi Dynäs och utmaningen består i att ångtemperaturen ska ökas från pannan för att maximera energiproduktionen i turbinen, vilket förser hela fabriken med elektricitet och ånga. I dagsläget arbetar sodapannan vid ett tryck på 64,2 bar och 485°C. En ökning av temperaturen och därmed en ökning av entalpin kommer i sin tur möjliggöra ökad elproduktion. Syftet med arbetet är att ta fram förslag till åtgärder som kan implementeras för att öka den utgående ångtemperaturen, samt att lokalisera de komponenter som begränsar temperaturen.     Best Avaliable Techniques (BAT-villkor) för pappersproduktion beskriver hur en sodapanna kan effektiviseras gällande värmeöverförande ytor och elproduktion och dessa punkter användes som vägledning i studien. Med BAT och dess punkter om hur förbättringar kan implementeras samt uppgifter från Mondi Dynäs egna anställda kunde fokus läggas på överhettarna och dess design samt lasten på pannan.    Litteraturstudier utfördes gällande att effektivisera sodapannan och tyngden lades på materialval av överhettartuber för att motverka korrosion och designen av dem. Överhettaren står för 30% av värmeöverföringen och är avgörande för sluttemperaturen av ångan. Därefter gjordes beräkningar för att avgöra om sodapannan är lastad enligt design. Resultatet av studien visar att de föreslagna åtgärderna kan öka ångtemperaturen med 5% vilket motsvarar i en ökning av elproduktion motsvarande 20 miljoner kronor för spotpriset 2023. Studien fastställer även att tubmaterialen som idag används för överhettarna inte är optimala vilket påverkar värmeöverföringen och därmed utgående ångtemperatur, därför rekommenderas nya materialval. Svartlutstillförseln till pannan analyserades också med resultat att den är marginellt underlastad. / The paper and pulp industry is significant in Sweden, with its products being in high demand. Due to the extensive and energy-intensive nature of the industry, optimizing energy usage is crucial. This thesis focuses on investigating a recovery boiler and its outgoing steam temperature. The recovery boiler belongs to Mondi Dynäs, and the challenge is to increase the steam temperature from the boiler to maximize energy production in the turbine, which supplies electricity and steam to the entire factory. Currently, the recovery boiler operates at a pressure of 64.2 bar and 485°C. Increasing the temperature and consequently the enthalpy will enable increased electricity production. The objective of this work is to propose measures that can be implemented to increase the outgoing steam temperature and identify the components limiting the temperature.   The Best Available Techniques (BAT) for pulp production describe how a recovery boiler can be optimized in terms of heat transfer surfaces and electricity production. These points were used as guidance in the study. With BAT and input from Mondi Dynäs employees, the focus was placed on the superheaters and their design, as well as the load on the boiler.   Literature studies were conducted to enhance the recovery boiler, with emphasis on the material selection of superheater tubes to prevent corrosion and their design. The superheater accounts for 30% of heat transfer and is crucial for the final steam temperature. Calculations were then performed to determine if the recovery boiler is loaded according to design.   The results of the study indicate that the proposed measures can increase the steam temperature by 5%, corresponding to an increase in electricity production worth 20 million SEK for the spot price in 2023. The study also establishes that the currently used tube materials for the superheaters are not optimal, affecting heat transfer and the outgoing steam temperature. Therefore, new material choices are recommended. The black liquor supply to the boiler was also analysed, revealing a marginal underload.

科学研究費補助金 研究種目:基盤研究(A)(2) 課題番号:08555101 研究代表者:早川 義一 研究期間:1996-1997年度