Energy Utilization of Secondary Raw Materials and Alternative Energy Sources - Centre for Energy and Environmental Technologies VSB-TUO

Hydrogen technology

Fuel cells for electricity generation are very sensitive to the purity of fuel hydrogen. It is therefore necessary to solve the problem of the influence of individual impurities on the performance and life of the fuel cell. The effect of these impurities needs to be monitored both individually and within mixtures of these components due to the possibility of a synergistic effect and a significant reduction in fuel cell performance. Determining these characteristics requires a multidisciplinary approach and the involvement of not only electromechanics, but also physical chemistry and chemical engineering, because in addition to measuring the current characteristics of the cells and their design, it is important to know the chemical equilibria in individual cell types, as well as on the surface of the electrodes themselves. The sampling and storage of fuel hydrogen, including the analysis of impurities, is another separate issue.

Catalytic pyrolysis and refining of products

Hydrogen is produced mainly by steam natural gas reforming. The disadvantage of this method is, in addition to the large amount of CO2 emissions, the consumption of fossil fuel (natural gas) itself. Therefore, it is necessary to focus on making use of waste CO2 and the hydrogen produced by electrolysis with excess cheap energy to produce other substances with energy potential. Another problem is the chemical recycling of waste polymers, for which the catalytic pyrolysis method is often used today. Although a significant proportion of monomers can be obtained by this method, the resulting pyrolysis oil, however, contains a significant amount of impurities causing problems in the downstream petrochemical industry. This is yet another reason it is necessary to focus on streamlining catalytic pyrolysis and to conduct research into other refining processes for the use of pyrolysis oils in industry.

Plasma gasification

A big advantage of plasma gasification technology is the possibility of energy utilization of tertiary raw materials (waste) and their thermochemical conversion into synthetic heating gas, with the simultaneous generation of a large amount of heat. This technology will decompose the organic part of the waste into further usable syngas composed mainly of CO and H2, and the inorganic part of the waste without greater energy value is vitrified and remains in the form of non-leachable, inert slag. The resulting syngas can be further used, e.g. after suitable purification to produce hydrogen. Although the system for cleaning gaseous substances, e.g., at waste incinerators, is very efficient and technologically mastered, the purity to which synthesis gas needs to be purified for further use brings considerable complications and requires a deeper analysis of current technologies and the development of techniques such as dry reforming, etc.

Separation of hydrogen from process gases

Usage of process gases as an efficient source for hydrogen production is innovative and will bring new knowledge in this field. There are a wide range of technologies that make it possible to increase the share of energy-valuable gas, i.e., separate unwanted impurities from it. Research activities in our laboratory are focused on the recovery of various waste and process gases using membrane separation technology. Research and development in this area will bring new materials capable for efficient hydrogen separation with long application potential in the near future. The advantages of membrane separation include procedural simplicity, low energy costs and independence from slight changes in the composition of the gases. Main activities are focused on the development and testing of membrane processes with application potential and safety aspects.

Biomass processing using microwave pyrolysis

The research focuses on the influence of procedural parameters of microwave pyrolysis and copyrolysis, the procedural balance, the influence of input material/mixture composition on the quality of output products (pyrolysis gas, liquid and solid residue), the influence on the turbostratic carbon structure, etc., on a laboratory scale, including the transfer to a semi-operational scale.

Thermal transformation of waste into energy under oxidizing conditions

This involves research into the incineration of waste and its components and the incineration of solid alternative fuels prepared from waste, along with related research into emission products produced during the incineration of the above waste/fuels and putting forth a proposal for measures to reduce the amounts of these products.

Processing of biodegradable waste

Research in the field of the pre-treatment of bio-waste and biomass, prior to biological treatment, includes mechanical pre-treatment, biological pre-treatment or other methods such as physico-chemical methods. We deal with the processing of bio-waste and biomass by anaerobic digestion into methane-rich biogas usable directly or after an upgrade to Bio methane or BioCNG, and the processing of bio-waste and biomass by biochemical fermentation processes into hydrogen-rich biogas, which can be used either directly or after an upgrade to BioH2.

Conversion/production of alternative fuel from process gases using Fischer-Tropsch synthesis

The main goal of this research is the production of alternative fuels from process gases using F-T synthesis and its purification for use in various end equipment’s. There is currently a worldwide demand for the development of energy-efficient, economical and environmentally-friendly processes for the sustainable production of liquid alternative fuels as a substitute for chemical compounds derived from oil. FTS is an example of a heterogeneously catalyzed reaction in which synthesis gas is transformed into a wide range of hydrocarbon products, and the process of producing this synthetic fuel is called GTL (Gas to Liquids). The first area of research is focused on the testing of various catalysts, where their catalytic activity and the effect on the composition of the resulting products are monitored. The second area of research is oriented on the testing the performance of manufactured FTS products with the aim of processing into motor fuels or petrochemical products.

Safety of hydrogen technologies

The risk of fire and hydrogen explosions is associated with many technological devices in various industries, especially in the energy and chemical industries, where the explosion of flammable gas is often considered one of the possible emergency scenarios. In the latter half of the 20th century, when the systematic study of fires and explosions of flammable gases began, numerous experimental and theoretical studies dealing with the nature of radiation and the transmission of an explosion wave were also carried out. From the perspective of the danger of its wide range of explosiveness, the problem with this gas is its low initiation energy and ignorance of its behavior under other than atmospheric conditions. The study of hydrogen explosions can be further combined with research on liquid hydrocarbon vapors and aerosol dispersions using a unique explosive autoclave and analytical techniques, and it can provide us with much information on the basic principles of combustion chemistry and characterize important factors in technical and fire safety practice.

ORC technology

The organic Rankine Cycle (ORC) is an alternative technology for electricity generation, which is applicable primarily in the use of low-potential heat. A special working fluid allows the ORC unit to recoverheat from low temperature (even below 100°C) energy sources such as waste heat, solar or geothermal energy. The research team is mainly engaged in the development and testing of prototypes of ORC units or micro-cogeneration systems. This is a technology of combined heat and power generation with an installed capacity of up to 50 kWe, which is still in the early stages of commercialization. The ORC unit of this size has great potential not only in industry but, with gradual miniaturization, also in the commercial and residential spheres. In this context, R&D activities focus on improving individual components and the overall optimization of thermodynamic cycle to achieve high energy efficiency and operational safety of ORC units with a power output of up to about 10 kWe. The main directions of research include the selection of a suitable working fluid and the energy transformation processes in an expansion device.