Carbon capture and storage (CCS) is one of the most promising technologies that may significantly reduce CO2 emissions. A better understanding of the thermo-physical properties of CO2 mixtures is required for the design and operation of different CCS processes. Before the knowledge gaps of the property models are being filled, it is important to identify the properties that can significantly influence the processes and find the proper property models. 

In this thesis, the status and progress of property impacts on CCS processes were reviewed by a literature survey. The studied CCS processes in this thesis include CO2 conditioning, transport, and storage. The results show that heat capacity and density are most important for the pumping process in CO2 conditioning systems, while heat capacity and compressibility have greater impacts on compression processes. In addition, density is the most important in CO2 pipeline transport and CO2 storage.

To follow up the knowledge gaps of the property impacts identified in the literature survey, quantitative impacts of the related properties on design and operation of key components including the multi-stream plate-fin heat exchanger and the centrifugal compressor, as well as the cryogenic process performance, were investigated by a sensitivity analysis. The results show that thermal conductivity has the most significant impact on heat exchanger sizing. Density and enthalpy have the most significant impact on the compressor impeller diameter and on the isentropic efficiency. In addition, thermal conductivity has the most significant impact on the capture rate of CO2, CO2 purity, and the operation cost of the cryogenic separation process. Hence, developing a more accurate thermal conductivity model should be prioritized for process design and operation of the cryogenic separation.

The performances of the thermal conductivity and viscosity models were evaluated for CO2 mixtures with non-condensable impurities. The results show that the KRW (Kestin-Ro-Wakeham) model is recommended for predicting the viscosity. For estimating thermal conductivity, the GERG (Groupe Européen de Recherches Gazières) model is the most accurate. 

Avskiljning och lagring av koldioxid (CCS) är en av de tekniker som kan förväntas bidra till signifikanta minskningar av koldioxidutsläpp till atmosfären. En ökad förståelse för de termofysikaliska egenskaperna för olika koldioxidblandningar är nödvändig för utformning och drift av de olika processer som är relevanta för CCS. För att fylla kunskapsluckorna behöver de viktigaste tillståndsstorheterna, dvs de som i hög grad påverkar processer för CCS, identifieras och modeller för att beskriva dessa termofysikaliska tillståndsstorheter måste utvärderas.

Nuvarande status av hur tillståndstorheterna påverkar olika relevanta processer, har granskats i denna avhandling genom en litteraturstudie. Processerna som har studerats är konditionering, lagring och transport av koldioxid. Litteraturstudien visar att värmekapacitet och densitet är viktigast för pumpningsprocesser, medan värmekapacitet och kompressibilitet har större inverkan på kompressionsprocesserna. Dessutom är densitet och värmekapacitet de viktigaste tillstånds­storheterna för transport av koldioxid i gasledning. Vid lagring av koldioxid är densitet och viskositet de viktigaste egenskaperna.

De kunskapsluckor om tillståndstorheternas påverkan, som identi­fierades vid litteraturundersökningen, har i denna avhandling undersökts kvantitativt genom känslighetsanalys. Det gäller design och drift av nyckel­komponen­terna flerströms plattvärmeväxlare och centrifugal­kompressor, men även hela den kryogena processens prestanda. Resultaten visar att värmekonduktiviteten har den största inverkan på dimensionering av värmeväxlare. Densitet och entalpi påverkar i högsta grad kompressorns impellerdiameter och dess isentropiska verkningsgrad. Dessutom har värmekonduktiviteten den största påverkan på avskiljningshastigheten för koldioxid, den avskilda koldioxidens renhet och driftskostnaden för den kryogena separationsprocessen. Därför bör utvecklingen av en noggrannare värmekonduktivitetsmodell prioriteras för den kryogena separationsprocessens design och drift.

Prestandan hos viskositetsmodeller och värmekonduktivitetsmodeller utvärderades även med avseende på tillståndens påverkan på olika kol­dioxid­­samman­sättningar med icke-kondenserbara föroreningar. Resul­taten visar att KRW-modellen (Kestin-Ro-Wakeham) är mest lämplig för att prediktera viskositet och att GERG-modellen (Groupe Européen de Recherches Gazières) är mest lämplig för att uppskatta värmelednings­förmåga. 

Oxy-fuel combustion is one of the most promising technologies for CO 2 capture for power plants. In oxy-fuel combustion plants, cryogenic process can be applied for CO 2 purification because the main impurities in flue gas are non-condensable gases. The multi-stream plate-fin heat exchanger is one of the most important components in the CO 2 cryogenic system. In-depth understanding of the impacts of property on the heat exchanger is of importance for appropriate design. In order to investigate the impacts of properties on sizing the heat exchanger and to further identify the key properties to be prioritized for the property model development, this paper presented the design procedure for the plate-fin multi-stream heat exchanger for the CO 2 cryogenic process. Sensitivity study was conducted to analyze the impacts of thermos-physical properties including density, viscosity, heat capacity and thermal conductivity. The results show that thermal conductivity has the most significant impact and hence, developing a more accurate thermal conductivity model is more important for the heat exchanger design. In addition, even though viscosity has less significant impact compared to other properties, the larger deviation range of current viscosity models may lead to higher uncertainties in volume design and annual capital cost of heat exchanger.

Considering the targets of Thailand in terms of renewable energy exploitation and decarbonization of the shrimp farming sector, this work evaluates several scenarios for optimal integration of hybrid renewable energy systems into a representative shrimp farm. In particular, floating and floating-tracking PV systems are considered as alternatives for the exploitation of solar energy to meet the shrimp farm electricity demand. By developing a dynamic techno-economic simulation and optimization model, the following renewable energy systems have been evaluated: PV and wind based hybrid energy systems, off-grid and on-grid PV based hybrid energy systems, ground mounted and floating PV based hybrid energy systems, and floating and floating-tracking PV based hybrid energy systems. From a water-energy nexus viewpoint, floating PV systems have shown significant impacts on the reduction of evaporation losses, even if the energy savings for water pumping are moderate due to the low hydraulic head. Nevertheless, the study on the synergies between water for food and power production has highlighted that the integration of floating PV represents a key solution for reducing the environmental impacts of shrimp farming. For the selected location, the results have shown that PV systems represent the best renewable solution to be integrated into a hybrid energy system due to the abundance of solar energy resources as compared to the moderate wind resources. The integration of PV systems in off-grid configurations allows to reach high renewable reliabilities up to 40% by reducing the levelized cost of electricity. Higher renewable reliabilities can only be achieved by integrating energy storage solutions but leading to higher levelized cost of electricity. Although the floating-tracking PV systems show higher investment costs as compared to the reference floating PV systems, both solutions show similar competiveness for reliabilities up to 45% due to the higher electricity production of the floating-tracking PV systems. The higher electricity production from the floating-tracking PV systems leads to a better competitiveness for reliabilities higher than 90% due to lower capacity requirements for the storage systems.

Reducing energy consumption and increasing the use of renewable energy in the building sector are crucial to the mitigation of climate change. Wind power driven heat pumps have been considered as a sustainable measure to supply heat to the detached houses, especially those that even do not have access to the electricity grid. This work is to investigate the dynamic performance of a heat pump system driven by wind turbine through dynamic simulations. In order to understand the influence on the thermal comfort, which is the primary purpose of space heating, the variation of indoor temperature has been simulated in details. Results show that the wind turbine is not able to provide the electricity required by the heat pump during the heating season due to the intermittent characteristic of wind power. To improve the system performance, the influences of the capacity of wind turbine, the size of battery and the setpoint of indoor temperature were assessed. It is found that increasing the capacity of wind turbines is not necessary to reduce the loss of load probability; while on the contrary, increasing the size of battery can always reduce the loss of load probability. The setpoint temperature clearly affects the loss of load probability. A higher setpoint temperature results in a higher loss of thermal comfort probability. In addition, it is also found that the time interval used in the dynamic simulation has significant influence on the result. In order to have more accurate results, it is of great importance to choose a high resolution time step to capture the dynamic behaviour of the heat supply and its effect on the indoor temperature. 

This study addresses the techno-economic analysis and comparison of systems for power and methanol production from biomass combined with solar and wind energy, from both technical and economic perspectives. Three different systems, based on Integrated Gasification Combined-Cycle (IGCC), Oxy-fuel combustion, and syngas gasification, were evaluated. The hydrogen required for methanol production comes from water electrolysis driven by solar and wind energy. In addition, the effect of location was discussed.

As a renewable energy, biogas produced from anaerobic digestion and landfill is playing a more and more important role in the energy market. Capturing CO2 from biogas can result in a negative CO2 emission. Depending on how biogas is utilized, there are different routes to capture CO2. A biogas plant that uses raw biogas to produce power and heat can be retrofitted by integrating CO2 capture. In order to identify the best option, three retrofits were compared from both technical and economic perspectives, including SYS-I, which captures CO2 from raw gas and produces biomethane instead of electricity and heat, SYS-II, which captures CO2 using MEA-based chemical absorption after the combustion of raw gas, and SYS-III, which captures CO2 by using oxy-fuel combustion of the raw gas. In general, SYS-I can achieve the highest profit and shortest payback time, mainly due to the high price of biomethane. SYSII and SYS-III are clearly influenced by carbon credit. In order to have positive profits for the retrofits of SYS-II and SYS-III, carbon credit needs to exceed 750SEK (or 100USD)/ton CO2 and 113 SEK (or 15USD)/ton CO2 respectively.

The effective technology for capturing CO2 at the low concentration is chemical absorption, due to the high reactivity between CO2 and aqueous amine solutions. To capture CO2, the process involves complex reactive separations. The accurate calculation of hydrodynamic properties, and mass and energy transfer are of importance for the design of the absorber and desorber columns. This paper performs the rate-based simulations of CO2 absorption by Monoethanolamine in Aspen Plus. In the calculation of the mass transfer coefficients, different mass transfer models were implemented. In comparison with the desorber, the impacts of mass transfer models were more significant in the simulation of the absorber. For both columns, the impacts of the mass transfer models on the concentration profiles were more significant than those on the temperature profiles. For the absorber, the maximum deviations occur at the bottom of the column for both the concentration and the temperature profiles. Different from the absorber, for the desorber, the maximum deviations occur close to the top of the column.

CO2 makes a major contribution to the climate change, and biomass renewable energy and carbon capture and storage (CCS) can be deployed to mitigate the CO2 emission. Cryogenic process for biogas upgrading combined with carbon capture is one of the most promising technologies. This paper reviewed the state-of-the-art of cryogenic systems for biogas upgrading combined with carbon capture, and introduced the status and progress of property impacts on the cryogenic systems with emphasize on phase equilibrium. The existing cryogenic systems can be classified as flash liquefaction system, distillation system, and liquefaction combined with desublimation system. The flash liquefaction system produces biomethane and CO2 in lower purity than the other two systems. Thermodynamic optimization on the flash liquefaction system and liquefaction combined with desublimation system should be done further, and comprehensive comparison between three cryogenic systems needs to be carried out. As to the phase equilibrium, PR EOS is safe to be used in predicting VLE and SVLE with an independent thermodynamic model describing the fugacity of the solid phase. However, the impacts of binary mixing parameter, different EOS models and mixing rules, on the performance of the cryogenic system need to be identified in the future.

The cryogenic process is used for CO2 purification in oxy-fuel combustion power plant, and multi-stream heat exchanger is one of the most important components. Viscosity and thermal conductivity are key transport properties in the design of plate-fin multi-stream heat exchanger. It is necessary to evaluate the impacts of viscosity and thermal conductivity models on the design of the heat exchanger. In this paper, different viscosity models and thermal conductivity models for CO2 mixtures with non-condensable impurities were first evaluated separately by comparing the calculated results with experimental data. Results show that for viscosity, the absolute average deviation of KRW model is the smallest, which is 1.3%. For thermal conductivity, model developed by Ely and Hanley, with absolute average deviation of 3.5%, is recommended. The impact of property models on the design of plate-fin multi-stream heat exchanger was also analyzed. The thermal conductivity model has a noticeable impact on the plate-fin multi-stream heat exchanger design, and the deviation in design size of heat exchanger by using different thermal conductivity models may reach up to 7.5%. The future work on how to improve the property models was discussed.

The multi-stream plate-fin heat exchanger is one of the most important components in the CO2 cryogenic system. Appropriate design methodology and in-depth analysis of property on the heat exchanger are of importance. This paper, as part I of the two-paper series, presented the design procedure for the multi-stream plate-fin heat exchanger in CO2 cryogenic process. Sensitivity study was also conducted to analyze the impacts of thermos-physical properties including density, viscosity, heat capacity and thermal conductivity. The results show that thermal conductivity has the most significant impact and it should be prioritized to develop a more accurate thermal conductivity model for the heat exchanger design. In addition, viscosity has least significant impact but the higher uncertainty range of viscosity may lead to a higher possible deviation in volume design.