作者：
Ian C.KempCarl-Gustav BergHyprotech UK Aspen Technology
Gemini Building Fermi Avenue Harwell Business Centre Didcot Oxfordshire OX11 0QR U.K.Process Design Laboratory Faculty of Chemical Engineering Abo Akademi University Biskopsgatan 8 FIN-20500 Abo FINLAND
Determination of the wet-bulb temperature at the surface of a material is the basis of one class ofhumidity measuring instruments, and is important in industrial applications such as dryer modelling and simula-tion. T...
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Determination of the wet-bulb temperature at the surface of a material is the basis of one class ofhumidity measuring instruments, and is important in industrial applications such as dryer modelling and simula-tion. The psychrometer equation is a frequently used method of estimating wet-bulb temperature, and contains apsychrometer 'constant'. Analysis shows that this is in fact a variable coefficient affected by temperature, pressure,radiation and conduction effects, and the identity of the gas and vapour. Radiation and conduction affect the dif-ference between adiabatic saturation temperature and indicated wet-bulb temperature. Inconsistencies in currentlyrecommended values for the psychrometer coefficient, including published international standards, are identifiedand explained. Particular problems arise when the enhancement factor is applied to vapour pressure to accountfor non-ideality of gases. Special considerations are also needed for wet-bulb temperatures approaching the boilingpoint, where the psychrometer coefficient tends to zero. Self-consistent recommendations recently published in thenew British Standard BS1339 are given, which cover both the air-water system and a general vapour-gas system.
In this paper effects of the shear stress on the behaviour of plant cell Rhodiola rosea L. (Crassulaceae) aggregates in suspension culture cultivated in vitro in the batch, Rushton-type stirred tank reactor are studie...
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In this paper effects of the shear stress on the behaviour of plant cell Rhodiola rosea L. (Crassulaceae) aggregates in suspension culture cultivated in vitro in the batch, Rushton-type stirred tank reactor are studied. Rhodiola rosea extracts positive effects, for human body, were the practical reason the following investigations on this species (Baldyga et al., 2002). Biological materials are often sensitive on mechanical shear stresses, which caused "shear problem" in biotechnology. Presentation of the simulation results of suspension culture history is the aim of this work.
Fossil fuel combustion leads to acidic pollutants, like SO2, NOx, HCl emission. Different control technologies are proposed however, the most popular method is combination of wet FGD (flue gas desulfurization) and SCR...
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Conception, design and application of laboratory plant for training of students of chemicalengineering in automatic control are presented. Training programme is composed on such a way that all control methods are con...
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Fossil fuel combustion leads to acidic pollutants, like SO2, NOx, HCl emission. Different control technologies are proposed however, the most popular method is combination of wet FGD (flue gas desulfurization) and SCR...
Fossil fuel combustion leads to acidic pollutants, like SO2, NOx, HCl emission. Different control technologies are proposed however, the most popular method is combination of wet FGD (flue gas desulfurization) and SCR (selective catalytic reduction). First, using lime or limestone slurry leads to SO2 capture, and gypsum is a product. The second process where ammonia is used as reagent and nitrogen oxides are reduced over catalyst surface to gaseous nitrogen removes NOx. New advanced method using electron accelerators for simultaneous SO2 and NOx removal has been developed in Japan, the USA, Germany and Poland. Both pollutants are removed with high efficiency and byproduct can be applied as fertilizer. Two industrial plants have been already constructed. One in China and second in Poland, third one is under construction in Japan. Information on the Polish plant is presented in the paper. Plant has been constructed at Power Station Pomorzany, Szczecin (Dolna Odra Electropower Stations Group) and treats flue gases from two Benson boilers 60 MWe and 100 MWth each. Flow rate of the flue gas stream is equal to 270 000 Nm3/h. Four transformer accelerators, 700 keV electron energy and 260 kW beam power each were applied. With its 1.05 MW total beam power installed it is a biggest radiation facility over the world, nowadays. Description of the plant and results obtained has been presented in the paper.
Waste heat recovery boilers as applied in refuse waste incinerators are susceptible to fouling. On the tube bundles in the boiler deposits are observed ranging from thin and powdery to thick and sintered with large ri...
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ISBN:
(纸本)9036514665
Waste heat recovery boilers as applied in refuse waste incinerators are susceptible to fouling. On the tube bundles in the boiler deposits are observed ranging from thin and powdery to thick and sintered with large ridges at the upstream side of the tubes. Both types of layers result in a decrease of the overall heat transfer coefficient of about 27%. To optimize the geometry of the bundle such that the formation of layers is minimized a model is developed that, as a function of the geometry, predicts the local deposition rate of particles. The model incorporates both the transport and the sticking of these particles to the surface. The applied sticking model is based on the two-body approach. The validity of this approach is shown using well-defined experiments in which the rebound characteristics of particles impacting on a powdery deposit are measured. Using the results from the impact experiments the deposition rate is calculated for a tube bank geometry with a varying pitch. The calculated deposition rates, when using the sticking model, are in the same order as the deposition rates reported for the industrial case. From these first calculations, it also appears that the pitch has a strong influence on the formation of a deposit on the tubes.
Despite many control theoretic and numerical advances, up to now there is no realistic feasibility study of modern nonlinear model predictive control (NMPC) schemes for the real-time control of large-scale processes. ...
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