B.S.(Diploma),Chemical Engineering N.T.U. Athens, 1976
Ph.D. Chemical Engineering University of Patras, 1993
Main research interests
SO2 and CO2 emissions
Sulfur dioxide is one of the most important anthropogenic atmospheric pollutants and its release greatly affects human health and the pollution of an area. 60% of total SO2 emissions to the atmosphere comes from burning coal to generate energy. Besides SO2, during the combustion of carbon it is released into the atmosphere, also, carbon dioxide. After several years of research, CO2 has been shown to be the dominant atmospheric pollutant that causes the "greenhouse effect". In an effort to reduce SO2 and CO2 emissions from power plants, a number of technologies have been developed that utilize calcium-based sorbents (CaCO3, CaO) either to capture one of the two pollutants or to simultaneously capture both pollutants at the same time.
The use of Ca-based sorbents to reduce SO2 emissions from coal-fired power plants has attracted worldwide interest for the last 90 years. Calcium oxide or limestone have often been used in fluidized bed or powdered carbon burners. Certainly, in countries where the introduction of fluidized bed technology is not feasible in the near future and where limestone feed on existing powdered lignite burners is unprofitable due to the very low calorific power of the used lignite, a dry or wet desulphurization process can significantly reduce SO2 emissions from power plants that burn powdered lignite.
At this stage, we are studying the retention of SO2 by the flue gases of powdered lignite burners, using a dry or wet process in CaCO3 / CaO and lignite reactors. The study includes experiments on laboratory reactors, mathematical modeling, numerical simulation, parametric analysis and optimization in laboratory and industrial conditions. Experiments are also carried out for the CaCO3 calcination reaction. Finally, we study the carbonization reaction of CaO with CO2. Specifically, the study includes mathematical modeling, numerical simulation and parametric analysis.
Impact of sulphates on durability of concrete structures
Concrete is the most common building material of our days. Despite the significant advances made in recent years in concrete technology, the problems of inadequate durability persist in a dramatic increase. The concrete deterioration over time is the result of various mechanical, physical, chemical or biological processes. The chemical processes that cause concrete deterioration can be distinguished in two categories, those affecting the concrete and those affecting the steel reinforcement of the concrete. In the first subclass there is the chemical effect of harmful substances (molecules or ions) on the concrete. A necessary condition for chemical reactions to occur in the concrete is the presence of water. In general the reactions between harmful components, either present in the concrete or mainly transferred by the environment, and the reactants of the concrete take place when one meets the other. However, due to the low rate of transfer of these components into the mass of concrete, these reactions may need several years to demonstrate their damaging results. In practice, the most common chemical effects on concrete are: the effect of acids, the effect of sulphate and the alkali-silica reaction.
The effect of sulphates on concrete is the reaction of sulphate ions mainly with the aluminate phase of cement, which causes internal expansion in the concrete eventually leading to cracking and decomposition. This action usually occurs when the concrete is in contact with a soil rich in sulphates. For practical handling of this deterioration mechanism, specific materials and limits have been proposed for the concrete composition.
The subject of our research effort is the bibliographic research, the formulation and the solution of a mathematical model and the experimental investigation of the concrete deterioration through the action of sulphates.
Design of LNG Storage and HandlingFacility
Natural gas is considered to have significant economic and environmental advantages compared to other liquid or solid fossil fuels. For this reason its consumption has increased dramatically over the last decades in Greece and also globally. Natural gas is usually stored in the form of liquefied natural gas (LNG) to an appropriate storage facility before it can be distributed.
The aim of our work is to perform literature review on the technical issues involved in a typical LNG storage facility. More specifically, we study the escalation of the size of the storage facility with respect to the quantity of LNG stored, the safety issues involved and their qualitative and quantitative characteristics and the minimum safety distance between the LNG storage facility and populated areas.
7. X.M. Theodorakopoulos, X.D. Bontzolis, and D.N. Spartinos, «Experimental study and parametric analysis of limestone fixed bed reactor to capture SO2», (in Greek), Proceedings of the 10th Panhellenic Scientific Conference in Chemical Engineering, Patras, Greece (2015).