1/2013
Current Issues and Projects in the Storage and Transport of Oil to the Czech Republic
Biogas flow modeling through the adsorbent bed
Biogas produced by the anaerobic decomposition of organic material contains in addition to methane and CO2 also a number of other substances, some of which cause problems by its energetic use. Among such substances include hydrogen sulfide and low molecular siloxanes. To ensure reliable operation of the biogas-fired cogeneration units, it is therefore necessary to install appropriate technology to remove these harmful components of biogas. A suitable method seems to be adsorption. Many operational applications are already using adsorption equipment for the biogas cleaning. Some of them have problems with a steady flow of the entire volume of the gas through the adsorption bed.
This paper is focused on modeling of the biogas flow through the adsorption bed in the CFD. Biogas flow simulations were performed on the model of the adsorber, which had the same characteristics as the real device. The findings simulation calculations provided an overall view of the flow distribution in the adsorber, size, pressure loss when passing through the adsorber and the distribution of velocity in the adsorption layer placed in the adsorber.
Mathematical Modelling of Natural Gas Dehydration by Adsorption Process
The paper deals with gas dehydration and hydrocarbon recovery from natural gas using adsorption process. A mathematical model of adsorption process is developed for the simulation of natural gas dehydration on a real unit which is capable of prediction of loading and regeneration time. The results are discussed. The paper also provides theoretical background for understanding the process and problem solving.
Measuring a Discharge Coefficient of an Orifice for an Unsteady Compressible Flow
There are many applications where a compressible gas flows through an orifice or a nozzle. This complex process has been examined for long time. Nevertheless current one or two dimensional mathematic and semi-empirical theories that predict a flow of a compressible gas through an orifice during an unsteady discharge from a vessel are only partially successful. It is impossible to treat all factors that might affect such a discharge. An experimental examination of a compressible gas flow through an orifice is still important part for evaluation and prediction of a discharge coefficient. This paper brings an idea for setup an apparatus on which a broad range of properties of an orifice can be tested. Several groups of properties were tested on different types of orifices and the results are presented.
Lignite multidust in technological conditions of production expanded clay
This study is focused on the energy balance that declares it can be more cost efficient to replace natural gas with coal dust during the production of expanded clay using the rotary kiln.
Thermogravimetric analysis of ashes from biomass combustion
A new method thermogravimetric analysis of unburned carbon using Boudouard reaction is suggested, mainly for ashes from biomass combustion. The method is based on measurement of weight loss in the sample using inert atmosphere, then that in an atmosphere of carbon dioxide. The difference between these losses then determines the content of unburned carbon. The method does not require the acid leaching to remove carbonates and can be used for samples with higher content of carbonates and portlandite; it covers a wide range of content of unburned carbon. The proposed method has been tested on two contrasting ash samples from two industrial combustors processing straw and woodchips. Determination provided accurate and precise results.