- Västerås, Vastmanlands Lan, Sweden
Erik Dahlquist
Mälardalen University, Est, Faculty Member
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Chapter 12: Modelling and simulation in the Pulp andPaper Industry : Current state and future perspectives
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The result of todays global and increasingly tough competition is narrow market windows and a demand for quick volume increases in production. This in turn means increased demands for a rapid and ...
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ABSTRACT
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The manufacturing sector is one of the biggest energy consumers. The iron and steel markets in China are growing very fast. Several studies have been performed to evaluate the Chinese steel sector in terms of energy savings and CO2... more
The manufacturing sector is one of the biggest energy consumers. The iron and steel markets in China are growing very fast. Several studies have been performed to evaluate the Chinese steel sector in terms of energy savings and CO2 emissions. The results of the studies showed that the major energy savings expected within 2020 and 2030 timeframe will be from industrial furnaces in steel mills. For the Swedish steel industry, it is important to be very efficient in order to remain competitive. The hot rolling process in the steel industry is a long process, where big slabs are heated in a furnace above the recrystallization temperature to roll the metal into a thin sheet and then the sheet is cooled at the Runout table using water. The amount of energy used during the process directly influences the price of the products. Moreover, the government policy on energy usage and CO2 emissions, the competitive market and the water scarcity, demand an optimal process operation to reduce energ...
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Due to the intense price-based global competition, rising operating cost, rapidly changing economic conditions and stringent environmental regulations, modern process and energy industries are confronting unprecedented challenges to... more
Due to the intense price-based global competition, rising operating cost, rapidly changing economic conditions and stringent environmental regulations, modern process and energy industries are confronting unprecedented challenges to maintain profitability. Therefore, improving the product quality and process efficiency while reducing the production cost and plant downtime are matters of utmost importance. These objectives are somewhat counteracting, and to satisfy them, optimal operation and control of the plant components are essential. Use of optimization not only improves the control and monitoring of assets, but also offers better coordination among different assets. Thus, it can lead to extensive savings in the energy and resource consumption, and consequently offer reduction in operational costs, by offering better control, diagnostics and decision support. This is one of the main driving forces behind developing new methods, tools and frameworks. In this chapter, a generic le...
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Chapter 3 concentrates on demographical perspectives such as human population development in different regions. It also gives an historical background to human development. In most regions of the world the population increase dropped... more
Chapter 3 concentrates on demographical perspectives such as human population development in different regions. It also gives an historical background to human development. In most regions of the world the population increase dropped significantly as economy improved and political stability increased. The population is still increasing rapidly mainly in countries where the political stability is poor; especially in several African countries. Life expectancy has also increased dramatically over the last 100 years, giving many more old people close to 100 years, in relation to the total population. The historical development shows that steps were taken to dramatically increase productivity of crops in early farming, as well as during the “green revolution” over the last 50 years, with harvests more than doubling. We can also see that the population has dramatically decreased several times due to natural disasters like in 536 AC, due to volcanic activity as well as plague in the mid-fo...
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The mass flow sensors in a flue gas channel of a bio-fuel fired boiler are few and operate in a harsh environment. The purpose of the here used data treatment system is to identify and correct bad mass flow measurements. The system... more
The mass flow sensors in a flue gas channel of a bio-fuel fired boiler are few and operate in a harsh environment. The purpose of the here used data treatment system is to identify and correct bad mass flow measurements. The system consists of a gross error detection and isolation algorithm combined with data reconciliation. The data treatment system is
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Gasification of biomass is one of the technologies to convert solid fuel to gas for heat and power production. Gasification mechanism and efficiency has been studied for decades. However due to the complexity of the system and its... more
Gasification of biomass is one of the technologies to convert solid fuel to gas for heat and power production. Gasification mechanism and efficiency has been studied for decades. However due to the complexity of the system and its sensitivity to operating parameters, the relations and impacts of different parameters on the gas quality and gasifiers performance are still not clear.In this paper data that are collected from different Circulating fluidized bed gasifiers have been analyzed to detect the most influential operating parameters. The gas composition, carbon conversion and heating value of the gas are considered as the evaluation indexes to measure the quality of the product gas and gasifiers performance.The multivariate analysis statistical tool has been used in this study. Principal component analysis (PCA) shows the grouping between different gasifiers and the positive/negative correlation between operating parameters and concentration of different components in the product gas. Also the influencing parameters on carbon conversion and heating value of the gas have been investigated.The results show a strong negative correlation between CH4 and CO with equivalence ratio (ER). This means that increasing ER value would decrease CH4 and CO concentration. This happens since the reactions move more towards combustion. On the other hand H2 shows a strong positive correlation with temperature, pressure and steam to biomass ratio (S/B). This can be related to cracking of larger hydrocarbons in higher temperature and larger S/B. However due to the exothermic characteristic of water gas shift reaction, higher temperature would result in lower CO2 amount which proves the negative correlation between H2 and CO2 in this analysis.
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Electric propulsion system in trains has the highest efficiency compared to other propulsion systems (i.e. steam and diesel). Still, electric trains are not used on all the routes, due to the high setup and maintenance cost of the... more
Electric propulsion system in trains has the highest efficiency compared to other propulsion systems (i.e. steam and diesel). Still, electric trains are not used on all the routes, due to the high setup and maintenance cost of the catenary system. Energy storage technologies and the battery driven trains however, make it possible to have the electric trains on the non-electrified routes as well. High energy consumption of the electric trains, makes the energy management of such trains crucial to get the best use of the energy storage device. This paper suggests an algorithm for the optimal control of the catenary free operation of an electric train equipped with an onboard energy storage device. The algorithm is based on the discrete dynamic programming and Bellman’s backward approach. The objective function is to minimize the energy consumption, i.e. having the maximum battery level left at the end of the trip. The constraints are the trip time, battery capacity, local speed limits and limitations on the traction motor. Time is the independent variable and distance, velocity and battery level are the state variables. All of the four variables are discretized which results in some inaccuracy in the calculations, which is discussed in the paper. The train model and the algorithm are based on the equations of motion which makes the model adjustable for all sorts of electric trains and energy storage devices. Moreover, any type of electrical constraints such as the ones regarding the voltage output of the energy storage device or the power output can be enforced easily, due to the nature of the dynamic programming.
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Effect of wood chip moving velocity on NIR spectra acquisition and model calibration for lignin quantification
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The mass flow sensors in a flue gas channel of a bio-fuel fired boiler are few and operate in a harsh environment. The purpose of the here used data treatment system is to identify and correct bad mass flow measurements. The system... more
The mass flow sensors in a flue gas channel of a bio-fuel fired boiler are few and operate in a harsh environment. The purpose of the here used data treatment system is to identify and correct bad mass flow measurements. The system consists of a gross error detection and isolation algorithm combined with data reconciliation. The data treatment system is
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Composition of the waste-based fuel intended for incineration has substantial effect on combustion process performance and formation of environmentally harmful emissions. Fuel composition vary sign ...
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Research Interests: Computer Science, Energy Engineering, Process Control, Access Control, Agriculture, and 15 moreFault Detection, Process Monitoring, Fault Detection and Isolation, Reuse, Nutrients, Finite Difference Method, High Dimensionality, Dissolved Oxygen, Organic carbon, Nitrogen Removal, Biochemical Oxygen Demand, Ambient Conditions, Agricultural Robots, Dissolved Oxygen Contents, and Photosynthetic Activity
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Abstract A battery storage has emerged as the most widely-used storage option, due to its flexible and complementary functionality for renewable energy systems such as solar PV and wind power. In order to ensure the efficient operation of... more
Abstract A battery storage has emerged as the most widely-used storage option, due to its flexible and complementary functionality for renewable energy systems such as solar PV and wind power. In order to ensure the efficient operation of batteries in energy systems, a proper battery model is essential in predicting realistic battery performance under various operating conditions. Accurate knowledge of the state of charge, state of power, and battery efficiency is a necessity for the development of advanced grid management applications. This paper investigates the techno-economic impacts of two battery modelling scenarios on the sizing and optimization of a grid-connected PV-battery system. Scenario 1 is based on a common simple battery model and control strategy which represents the battery status without reflecting dynamic behavior. By contrast, Scenario 2 is based on a complex battery model involving estimation of battery current-voltage characteristics under various operating conditions. A rule-based operational strategy linked to a non-dominated sorting genetic algorithm is further employed for the simulation and multi-objective optimization of a grid-connected hybrid PV-battery system. The battery life cycle cost and the self-sufficiency ratio are analyzed and optimized as objective functions, and battery capacity constitutes as a decision variable. The results show that in order to reach the same self-sufficiency ratio, the optimization of a hybrid energy system based on Scenario 1 leads to solutions with a higher life cycle cost and requiring bigger battery capacity, compared to that of Scenario 2. Moreover, under the same design parameters, the system optimization based on Scenario 2 delivers more power to the end-user, which leads to a higher self-sufficiency ratio compared to when the system is simulated based on Scenario 1. This study proves that an efficient battery model with sufficient accuracy is techno-economically more beneficial, and leads to more accurate battery sizing.
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Kappa number variability at the continuous digester outlet is a major concern for pulp and paper mills. It is evident that the aforementioned variability is strongly linked to the feedstock wood properties, particularly lignin content.... more
Kappa number variability at the continuous digester outlet is a major concern for pulp and paper mills. It is evident that the aforementioned variability is strongly linked to the feedstock wood properties, particularly lignin content. Online measurement of lignin content utilizing near-infrared spectroscopy at the inlet of the digester is paving the way for tighter control of the blow-line Kappa number. In this paper, an innovative approach of feedforwarding the lignin content to a model predictive controller was investigated with the help of modeling and simulation studies. For this purpose, a physics-based modeling library for continuous pulp digesters was developed and validated. Finally, model predictive control approaches with and without feedforwarding the lignin measurement were evaluated against current industrial control and proportional-integral-derivative (PID) schemes.
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In Sweden the utilization of household waste for energy purposes is quite significant already today. Individuals sort the household waste in different fractions where the organic biologically degradable material is separated into one... more
In Sweden the utilization of household waste for energy purposes is quite significant already today. Individuals sort the household waste in different fractions where the organic biologically degradable material is separated into one fraction, while other type of combustible materials into one or more fractions. The rest of the waste is normally going to recycling, like metal, glass and paper. Concerning industrial waste we have a similar situation. In Vastmanland and eastern Uppland a collection system with sorting of waste into many fractions has been in operations for 15 years. This has led to a situation, where most waste is sorted in a very good way. Just 1-2 % of the waste is put into the wrong container. At the central waste recycling plant at Gryta in Vasteras, the biologically degradable organic waste is mixed with fat sludge from restaurants and lay crops like clover and grass into a large biogas reactor. This now has been in operations for four years. It has been proven t...