High Performance Light Water Reactor : Design and Analyses

The High Performance Light Water Reactor is a nuclear reactor concept of the 4th generation which is cooled and moderated with supercritical water. The concept has been worked out by a consortium of European partners, co-funded by the European Commission. It features a once through steam cycle, a pressure vessel type reactor, and a compact containment with pressure suppression pool. The conceptual design enables to assess its feasibility, its safety features and its economic potential

Voimakattilan virumisen ja väsymisen jatkuvatoiminen seuranta

Increasing wind and solar power production and deregulation of electricity market have significantly changed electricity market environment in many areas such as Germany, Ireland and parts of USA. Consequently, demand for electricity production using combustion boiler units has been experiencing increasing fluctuation. This has been causing increasing amount of variable load operation and on-off cycles for these boilers. Such operation has undesired effects on condition of boiler pressure part and therefore operability and economic efficiency of whole boiler unit. Objective of first part of this work is to study mechanisms of creep and fatigue occurring in pressure vessels. Then, problems arising from cyclical operation of power boiler pressure part are introduced. Steam turbines are also briefly covered. The latter part of the work discusses possibilities for computer-assisted real time monitoring of boiler condition. More detailed description of a computer application made as a part of this thesis work is also given. One part of the work was to study, if there is need for such applications at the market. Using information provided by a real time monitoring application, it is possible to reduce problems related to creep, thermal stresses and following fatigue. There are reports indicating that underestimating costs related to cyclical boiler operation may have considerable financial consequences. Therefore it would be beneficial to have estimations on such costs. Several available commercial software products include features that as-sist in making these estimations

Energy Conversion Alternatives Study (ECAS), Westinghouse phase 1. Volume 2: Materials considerations

Extensive studies are presented which were carried out on materials behavior in nine advanced energy conversion systems employing coal and coal-derived fuels. The areas of materials behavior receiving particular attention in this regard are: (1) fireside corrosion and erosion in boiler and heat exchanger materials, (2) oxidation and hot corrosion of gas turbine materials, (3) liquid metal corrosion and mass transport, (4) high temperature steam corrosion, (5) compatability of materials with coal slag and MHD seed, (6) reaction of materials with impure helium, (7) allowable stresses for boiler and heat exchanger materials, (8) environmental effects on mechanical properties, and (9) liquid metal purity control and instrumentation. Such information was then utilized in recommending materials for use in the critical components of the power systems, and at the same time to identify materials problem areas and to evaluate qualitatively the difficulty of solving those problems. Specific materials recommendations for critical components of the nine advanced systems under study are contained in summary tables

Performance Investigation of Integrated Gasification Combined Cycle Power Plant for Polygeneration

Energy and environment are playing an important role in shaping the world at present and the path ahead into the future. Both affect the aspects of the economy, politics, health, and welfare. In addition, the growth of wind and photovoltaic plants has greatly increased the demand for flexible generation or storage options in the electricity market due to their fluctuation. The Integrated Gasification Combined Cycle (IGCC) with carbon capture for polygeneration of power and chemicals features the advantages of flexible power generation that has low CO₂ emissions, alongside essential chemicals for the industry or even production of fuels that for storage and then to be utilized during the peak time. Moreover, the ability to use biomass and Refuse Derived Fuel (RDF) as feedstock for IGCC contributes to waste management and better use of the resources. In the scope of this work, a process simulation model of an IGCC using Aspen Plus was developed based on a pilot-scale 0.5 MWth HTW gasifier and gas purification plant installed at TU Darmstadt. The gasification and purification pilot plant model was scaled up and then integrated with a CCPP for power generation. For the power generation part, a process simulation model of Combined Cycle Power Plant (CCPP) was built based on a 360 MWel General Electric (GE) STAG 109FA CCPP located at Prai in Malaysia. For chemical production, a methanol synthesis unit was also modeled and integrated with the IGCC model to enable polygeneration of electricity and methanol in an IGCC plant. To improve the performance of the IGCC, heat integration between the heat recovery steam generator (HRSG) and the syngas production process (gasification and purification) was applied. Additionally, an acid gas removal (AGR) process was adopted for the IGCC model. In this respect, three process simulation models for AGR were developed using three different solvents (Selexol, Rectisol, and a-MDEA) and then evaluated seeking a better performance of the IGCC. Furthermore, co-gasification of coal and refuse derived fuel in different mixing ratios were used and investigated. The evaluation of the developed IGCC power plant model for flexible polygeneration using HTW gasification technology shows a promising electrical efficiency of about 37.48% with a carbon capture rate of 90%. Also, the comparison between the three AGR processes shows that the Selexol process is the most efficient. Therefore, this process was used in the final configuration of the IGCC plant. Finally, a thermo-economic evaluation under volatile selling prices of IGCC products was executed to investigate the production regime and to make better decisions for production