Ladislav Bébar

Enzymatic hydrolysis of pretreated waste paper - source of raw material for production of liquid biofuels.

Enzymatic hydrolysis of waste paper is becoming a perspective way to obtain raw material for production of liquid biofuels. Reducing sugars solutions that arise from the process of saccharification are a precursors for following or simultaneous fermentation to ethanol. Different types of waste paper were evaluated, in terms of composition and usability, in order to select the appropriate type of the waste paper for the enzymatic hydrolysis process. Novozymes® enzymes NS50013 and NS50010 were used in a laboratory scale trials. Technological conditions, which seem to be the most suitable for hydrolysis after testing on cellulose pulp and filter paper, were applied to hydrolysis of widely available waste papers - offset paper, cardboard, recycled paper in two qualities, matte MYsol offset paper and for comparison again on model materials. The highest yields were achieved for the cardboard, which was further tested using various pretreatment combinations in purpose of increasing the hydrolysis yields.

Low NOx burners—prediction of emissions concentration based on design, measurements and modelling

This paper describes possible ways of prediction of nitrogen oxides formation during combustion of hydrocarbon fuels. Mathematical model based on experimental data acquired from the testing facility has been developed. The model enables to predict--at a high probability measure--the extent of nitrogen oxides emissions. The mathematical model of nitrogen oxide formation relies on the application of simplified kinetic equations describing the formation of nitrogen oxides at so-called equivalent temperature. It is a semi-empirical model that comes out of experimental knowledge. An important role played by the burner design itself has been emphasized and therefore an important supplementary parameter of the model is the characteristic of the burner design. It has been established that there was a good agreement between experimental data and those calculated by the application of the model to various conditions marked out by different combustion parameters in the combustion chamber. The results obtained by application of the model respect the influence of parameters validated by industrial practice that control the formation of nitrogen oxides in the course of fuel combustion. Such parameters-first of all-tare the temperature in the combustion chamber and the concentration of the substances taking part in the reaction. By application of the model, it is possible to assess the consequence of, for example the surplus of combustion air, the increase of temperature of combustion air, the supply of inert gas, etc. on the nitrogen oxides emissions of the operating burner under evaluation. Efficient combining of experience and sophisticated approach together with importance of thus access for an improved design are shown.

Waste to energy in the field of thermal processing of waste

Abstract Thermal treatment of waste is accompanied by the release of a considerable quantity of heat that depends on the heat value of the waste being processed. Heat is released by burning the combustible part of the waste as well as by burning an auxiliary fuel in the case of processing low heat value waste. An important task of process-technology solution is to utilize efficiently the heat value of the products of incineration and this way partially compensate for the costs of waste thermal treatment. This contribution deals with energy consumption in relation to utilization of heat value of thermal decomposition products produced from waste in cases of two different waste processing technologies. The alternatives assessed differ in the regime of waste destruction. The first alternative is an incineration plant operating under oxidizing regime, the second one is an incineration plant performing thermal decomposition in a gasification reactor as the first stage of the process.

Alternative arrangement of unit for thermal processing of wastes from polluted air

Abstract New efficient equipment for the thermal treatment of gas wastes from polluted air (incineration of volatile organic compounds and carbon monoxide) has been developed recently. This equipment can be used in various branches of industry (for the treatment of polluted air from paint shops, chemical cleaning systems, degreasing processes, printing machines, gas wastes from various chemical processes, for the thermal treatment of off-gases originating in refineries, in the production of plastic, the pharmaceutical industry, the food industry, laboratories, etc.). A principal idea of this equipment is based on placing the cylindrical combustion chamber inside a heat exchanger–polluted air preheater. Main advantages of this equipment are as follow: compactness and utilizing heat losses from the combustion chamber for additional preheating the polluted gas. Modified equipment for catalytic treatment can be used as an alternative unit. Various options of arrangement can be applied in industrial practice. This unit can be used as a compact one (minimization of space requirement owing to a convenient arrangement of fans), over pressure (only air fan), under pressure (only flue gas fan — recommended especially in cases where the polluted air is supplied by pressure). Waste to energy arrangement is that in the case of an excessive concentration of pollutants–combustibles. Then the energy of the outlet flue gas can be utilized not only for the polluted air preheating but also for steam generation, water heating or other purposes.