3/2011
Hydrates of Biogas
Methane hydrates are phenomenon which uses to be in the past connected only with Natural Gas transmission and possible exploitation of Natural gas hydrate fields. With fast development in the sector of Biogas and Biomethane production and utilization the risk of hydrate formation arose also in the field of transportation of alternative (or renewable) gaseous fuel (e.g. Biogas and Biomethane). The aim of this article is to introduce the influence of presence of carbon dioxide in in such fuel on hydrate forming equilibrium (i.e. system water-hydrocarbon-carbon dioxide) in order to minimalize the risk of hydrate formation under operating conditions.
Directions for Efficiency Improvement of Biofuels Production
The biofuels are plying increased role on motor fuel market. List of bio-fuels (bio-components) in accordance with EU legislation contains number of substances not widely utilised on the market. Most traditional are: FAME (in the Czech Republic methyl ether of rape seed oil) and bioethanol (relatively frequently also ETBE based on bioethanol). The availability and perspective of biocomponent in the Czech Republic is discussed resulting into conclusions that after 2018 new components or larger imports will be required in order to satisfy EU legislation. Specific attention is paid on improved effectiveness of cultivation of rape seeds and utilisation of by-products from FAME production: utilisation of sew, rape-meal and glycerol. Concept of 3E is introduced (Emissions, Energy Demand, Economics) specifying 3 main attributes for effective production in line with legal compliance. Specific attention is paid to bio-components price development in comparison to motor fuels identifying possible (speculative) crude price break-even point 149-176 USD/bbl when bio-fuels will become effective for use by refiners.
Turbocharged gas engine concept for the use of thermolysis gas
The paper deals with the suitable concept study of a gas turbocharged engine for combustion of thermolysis gas from sorted waste. A comparison of engine parameters for thermolysis and natural gas is made for gas turbocharged engine with intercooler in terms of air/fuel ratio, compression ratio and choice of turbocharger. The study is conducted using simulation tool GT-POWER and user models for knock, heat transfer and combustion. The results show that by using thermolysis gas versus natural gas in turbocharged gas engines can achieve higher efficiency without a significant impact on the life of key engine components.
The Optimization of the Gas Distribution in the Bag Filters With Non-standard Layout of Gas Ports
The performance of the bag filters depends on the layout of gas ports as well as on other factors. The article presents the method for the evaluation of these influences based on CFD. The advantage of presented method is in the simplified representation of the filter internals without distorting the results regarding the filter as a whole. The model is used to analyze the influence of ports mutual position, the hydraulic resistance of filter sections and of the total gas flow.
Gas turbines with externally heated working medium application in cogeneration units
The paper summarizes the theoretical and experimental knowledge related to the possibility of using indirectly fired gas turbine (IFGT) for the production of electricity in a cogeneration system. Advantages and disadvantages of the IFGT technology are discussed on a number of examples. Czech project, using the gas turbine with electrical output of 90 kW which is installed in municipal waste landfill in the village of Lany, is presented as a successful example.