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Denna rapport presenterar en optimering av "Carbon Capture & Storage" (CCS). Framför allt optimeras det för miljöns skull och minskningen av koldioxidens påverkan på miljön. I och med det sker en optimering av möjligheten att tjäna pengar på CCS för att ge ett ekonomiskt incitament till en mer storskalig lagring av koldioxid. Mer specifikt sker en optimering av injiceringshastigheter av koldioxid utifrån att maximera den tillåtna kostnaden givet en vinst. Det testades för en större vinst (girig) och en netto noll vinst (passiv). Detta gjordes genom genetisk algoritm (GA) och upprepade simuleringar med hjälp av open source toolboxen MRST och dess modul co2lab. Vidare implementerades det även en local search algorithm (LSA) som används för att testa och förbättra prestandan hos GA genom att snabbare konvergera resultat. Resultat och analys visar att en girig inställning kan leda till överinjektion av koldioxid, medan en passiv strategi kan vara för försiktig. Optimala resultat uppnåddes genom en kombination av GA och LSA, vilket balanserar mellan att maximera lagringen av koldioxid och minimera utsläpp. Slutligen visar simuleringar och resultat en tydlig effektivitet hos GA och LSA i att hitta optimala lösningar för koldioxidlagring för ett hypotetiskt scenario.

Metal-organic frameworks (MOFs) have come to the forefront over the past two decades because of their potential application in hydrocarbon separation under ambient conditions. MOFs are coordination polymers constructed by joining metal ions or metal clusters with organic linkers containing Lewis basic binding atoms. The main focus of the research pursued in this dissertation was to design and synthesize new metal-organic frameworks based on larger polycarboxyaryl linkers developed by our group. The linker design was as such to add a phenyl ring and an unsaturated C2 spacer to the analogous linkers based on linker expansion strategy. The aim of the linker design was to potentially increase the surface area, by virtue of the overall larger linker size, and afford higher adsorption energy to the hydrocarbon molecules (especially to the unsaturated hydrocarbons) owing to π(hydrocarbon)-π(linker) possibly chemisorptive stacking interactions, hence increasing their separations from impurities. To accomplish this goal, we reported several new MOFs and studied their separation abilities. We were also able to report MOFs for the capture of CO2 from industrial flue gases under ambient conditions.

Jordens befolkning behöver kraftigt reducera koldioxidutsläppen till atmosfären för att förhindra klimatförändringar. Klimatmål har sats upp av unioner och länder där de bland annat vill förhindra en global temperaturökning över 1.5 grader. För att uppnå dessa klimatmål menar forskare och institutioner på att stora mängder koldioxid kommer att behöva avskiljas vid utsläppskällor och lagras geologiskt (eng. carbon capture storage, förkortad CCS). I Sverige har ett fåtal CCS-projekt tagit fart men CCS är fortfarande inte kommersiellt tillgängligt. Frågeställningen för det här arbetet var därför: vilka är de mest relevanta utmaningar som kommersiellt tillgänglig CCS står inför idag i Sverige?Metoderna som användes var en litteraturstudie och tre\newline intervjuer. Personerna som intervjuades var en forskare från Chalmers Tekniska högskola, en chef från företaget Stockholm Exergi och en civilingenjör från projektet Northern lights. Utmaningarna delades in i kategorierna: tekniska-, politiska-, ekonomiska- och övriga utmaningar, för att enklare identifieras och jämföras. Resultaten visade att det fanns utmaningar i samtliga kategorier. Den tekniska utmaningen låg framförallt i att bygga upp och anpassa den tillgängliga CCS-tekniken till olika tillämpningsbara industrier. Politiskt var utmaningen främst att övertyga politiker att satsa på CCS, men också att införskaffa tillräckligt stora ekonomiska styrmedel, incitament och investeringar. Detta eftersom de som existerar idag antingen saknades helt eller ansågs vara för små. De ekonomiska utmaningarna var att stimulera investerare samt att bygga upp en fungerande och hållbar ekonomisk plan för CCS. I kategorin övriga utmaningar var den främsta utmaningen att övertyga befolkningen och att sprida kunskap kring CCS och dess potential. Avgränsningar i det här arbetet var framförallt bristen på resurser och tid. Fler intervjuer och en djupare litteraturstudie hade varit önskvärd för att fördjupa studien men begränsades av tid och möjligheter för kursens omfattning. / The world population need to reduce its carbon dioxide emissions to the atmosphere in order to prevent a climate change. Climate targets have been set by unions and countries to reduce carbon dioxide emissions before the average temperature rise exceeds 1.5 degrees Celsius. To achieve these climate goals, researchers and institutions believe large amounts of carbon dioxide needs to be stored below ground (carbon capture storage, abbreviated CCS). In Sweden have a small number of projects taken off, but CCS is still not commercially available. The question for this work was therefore: what are the most relevant challenges that commercially CCS currently faces in Sweden?The methods used were a literature study and three interviews.The persons interviewed were a researcher from Chalmers Tekniska university, a manager from the company Stockholm Exergi and an engineer from the Northern Lights project. The challenges were divided into four categories: technical-, political-, economic-, and other challenges, to make it easier to identify and compare. Results showed that there were challenges in all four categories. The technical challenge was mainly to build and adapt the available CCS technology to different types of industries. Politically, the challenge was primarily to increase their interest and support towards CCS. This along with the challenge of acquiring financial instruments, incentives and investments that was currently lacking or was too small. The economic challenges were to stimulate investors from both private and political quarters and to organize and operate a functioning and sustainable financial plan. In the category other challenges, the most mentioned challenge was convincing the population and to spread knowledge about CCS and its potential. Delimitations in this work was above all the lack of resources and time. More interviews anda deeper literature study would have been desirable to deepen the study but was limited by time and opportunities for the scope of the course.

An investigation into the commercial feasibility of Carbon Capture and Storage (CCS) technology as a competitive carbon abatement technology for New Zealand.

The first detailed systematic investigation of a cement plant with various carbon capture technologies has been performed. The calcium looping (Ca-looping) process has emerged as a leading option for this purpose, since this process applied to a cement plant provides an opportunity to use the CaO purge for clinker production. The Ca-looping process is comprised of two interconnected reactors where the carbonator captures CO2 from flue gases and the calciner regenerates the CaCO3 into CaO by oxy-combustion. Fully integrated process flowsheets have been developed and simulated in UniSim Design Suite from Honeywell. The detailed carbonator model has been implemented using Matlab and incorporated into UniSim to provide a full flowsheet simulation for an exemplary dry-feed cement plant as a user-defined operation. The base cement plant simulation was also modified to integrate three different carbon capture processes: membrane; indirect calcination; and amine-scrubbing. Furthermore, an advanced configuration of Ca-looping process has been investigated where the energy intensive air separation unit was replaced with a chemical looping combustion (CLC) cycle. Each case has been optimised to minimise its energy consumption and compared in terms of levelised cost of cement and its resulting cost of CO2 avoided at the same CO2 avoidance rate. The proposed integration of the Ca-looping process is capable of achieving over 90% CO2 avoidance with additional fuel consumption of 2.5 to 3.0 GJth/ton CO2 avoided. By using an advanced configuration of the Ca-looping process with a CLC cycle, the additional fuel consumption can be reduced to 1.7 GJth/ton CO2 avoided, but the cost of the oxygen carrier is the major concern for this system. Among the other CO2 capture options, the membrane process is a promising alternative for the Ca-looping process since it has a potential of achieving the target CO2 avoidance rate and purity requiring lower energy consumption. The indirect calcination process provides moderate levels of CO2 avoidance (up to 56%) without a need of an external capture process whereas the integration of the amine process in a cement plant is challenging as a result of the requirement of steam for solvent regeneration. Furthermore, considering zero net CO2 emissions associated with biomass combustion systems, a novel concept has been analysed to capture of CO2 in-situ with the Ca-looping process while operating the combustor of a dedicated biomass power plant at sufficiently low temperature. This process is capable of achieving 84% overall CO2 capture rate with an energy penalty of 5.2% when a proper heat exchanger network is designed with the support of a pinch analysis. The techno-economic performance of the biomass power plant with in-situ Ca-looping CO2 capture process was compared with that of the alternative biomass-air-fired and biomass-oxy-fired power plants.

Integrated Gasification Combined Cycle (IGCC) power plants have been considered as one of the best options for energy production in an environmental friendly manner. IGCC power plants are demonstrating better results, both in terms of plant performance and economics, when compared to a Pulverised Coal (PC) power plant with CO2 capture. The additional components required for an IGCC power plant when it is desired to operate in CO2 capture mode, give research potential with respect to an improved IGCC power plant performance. The IGCC power plant design framework studied and developed was based in DOE/NETL report and is presented. The conventional and CO2 capture IGCC power plants have been benchmarked in rigorous process flow diagrams developed using the commercial software Honeywell UniSim Design R400. As an essential part of the Innovative Gas Separations for Carbon Capture project (IGSCC EPSRC – EP/G062129/1) predictive simulation tools were produced to investigate the IGCC performance. The case studies considered include different gasification options for non-capture and carbon capture IGCCs, with a two stage Selexol process for the CO2 capture cases. Particular effort has been made to produce an accurate simulation component to describe the behaviour of the syngas in the Selexol solvent. The two stage Selexol configuration was investigated in detail and novel schemes are presented. No similar approaches have been reported in the literature, in terms of the proposed configuration and the capture efficiency. Moreover, innovative CO2 capture schemes incorporating combined units of physical absorption and membranes have been examined with respect to the power plant’s performance. In this thesis, contrary to other studies, all simulations cases have been conducted in unified flow diagrams. The results presented include overall investigations and can be a helpful tool for engineers and stakeholders in the decision making process.

In recent years, Integrated Gasification Combined Cycle Technology (IGCC) has become more common in clean coal power operations with carbon capture and sequestration (CCS). Great efforts have been spent on investigating ways to improve the efficiency, reduce costs, and further reduce greenhouse gas emissions. This study focuses on investigating two approaches to achieve these goals. First, replace the subcritical Rankine steam cycle with a supercritical steam cycle. Second, add different amounts of biomass as feedstock to reduce emissions. Finally, implement several types of CCS, including sweet- and sour-shift pre-combustion and post-combustion. Using the software, Thermoflow®, this study shows that utilizing biomass with coal up to 50% (wt.) can improve the efficiency, and reduce emissions: even making the plant carbon-negative when CCS is used. CCS is best administered pre-combustion using sour-shift, and supercritical steam cycles are thermally and economically better than subcritical cycles. Both capital and electricity costs have been presented.

A methodology for the thermodynamic-kinetic evaluation of circulating systems as TSA carbon capture processes is developed and used in the assessment of a novel CFB configuration against a benchmark (co-current riser). The novel CFB features a counter-current adsorber, a counter-current regenerator and a riser, the latter element playing a double role of solids conveyer and co-current adsorber. The advantages sought by using a counter-current adsorber are not only the more efficient gas-solid contact mode with respect co-current, but also a low pressure drop derived from operation at lower gas velocities and hydrostatic head partially supported on the contactor internals. Knowledge of the adsorption equilibrium alone is sufficient to realise the much higher sorbent circulation rates required by co-current configurations –compared to counter-current– to meet the stringent carbon capture specifications of 90% recovery and 95% purity. Higher solids circulation rates imply higher energy requirements for regeneration, and therefore research and development of co-current gas-solid contactors cannot be justified in terms of searching for energy-efficient post-combustion carbon capture processes. Parallel experimental investigation in the operation and fluid dynamics of cold model CFB rigs is carried out with the purposes of: 1) providing information that may impact the process performance and can be fed into the mathematical model used in the theoretical assessment for more realistic evaluation, and 2) determine gas and solids residence time distributions (RTDs), which are used for the estimation of axial dispersion and comparison with published results in similar systems. Gas RTD data is generated using a tracer pulse injection-detection technique, whereas RTD for the solid phase is studied using positron emission particle tracking (PEPT). The PEPT technique proved to be adequate for the identification of flow regimes in the novel design of the counter-current adsorber, featuring inclined orifice trays. At low gas velocities the particles flow straight down through the tray holes, whereas at higher velocities the particles flow down in zig-zag, increasing the residence time of the particles and reducing the particle axial dispersion, both beneficial in terms of separation efficiency.