Veljko Filipan

Solarized evaporation process

Abstract The minimization of fuel consumption in evaporation processes, could be achieved by using steam condensate heat recovery and also solar energy as a partial substitution for fossil fuels. In the presented article, the fuel savings methods in the one effect conventional and solarized processes are treated. The analysis includes the estimation of natural gas consumption, solar energy substitution and a summary of the savings for processes without and with condensate recovery. The reported results are obtained by calculations based on industrial plant data for NaNO 3 evaporation and measured irradiation for a selected location in Croatia

The influence of filler treatment on the mechanical properties and phase behavior of thermoplastic polyurethane/polypropylene blends

Thermoplastic polyurethane (TPU) and isotactic polypropylene (iPP) composites and their talc reinforced blends containing untreated and silane treated talc were investigated. The talc surface was modified with organosilane coupling agent in order to improve the polymer–filler interface interaction. TPU has been blended with iPP in a twin screw extruder and samples for investigation were prepared by injection moulding at different concentrations. The neat polymers, composites and blends were characterized with DMA, XRD, FTIR and tensile testing. The obtained results showed that mechanical properties of the talc filled TPU and iPP composites and TPU/iPP blends were improved with the addition of untreated and silane treated talc. The storage modulus of the TPU/iPP blends increased with the addition of untreated and silane treated talc, due to a stiffer interface which talc generated in the polymer matrix. The comparison among samples filled with untreated and silane treated talc filler showed that the polymer composites and TPU/iPP blends filled with silane treated talc displayed better mechanical properties. Silane addition improves the adhesion between the filler and the polymer matrix.

Energy conservation using a recuperative drying process

Energy savings in drying processes might be achieved by using a dryer exhaust heat for ventilation and supply air preheating and also water or space heating. One of the various possibilities for heat conservation is the process with recuperation. Having analyzed one-stage and two-stage recuperative drying, it was established that the heat economy with the two-stage process is approximately twice as good. Compared with the process without heat recovery, the energy savings for the ventilation air heater is 41% and for the ventilation and supply air heaters is about 60%.

Održivo gospodarenje otpadom s mehaničko biološkom obradom i energetskim iskorištavanjem

Professional paper A successful example of sustainable waste management applicable to towns or regions with more than two hundred thousand inhabitants is discussed. Modern landfill with composting facility, mechanical biological treatment and energy utilization of waste in the town of Celje, Slovenia, covering the needs of 24 surrounding municipalities, is described in details. The advantages, but also some difficulties that were indicated during the operation of the system are shown. Applied processing technology significantly reduces waste, extracts secondary raw materials and uses waste as an energy source, so achieving a sustainable system for a number of years. According to this successful example, our aim is to encourage similar projects in Croatia as well.

Fleksibilnost MBO postrojenja

Subject rewiew Mechanical Biological Treatment (MBT) of waste represents a series of mechanical and biological processes which have the purpose to reduce the amount of waste that is placed on a landfill. In accordance to the ‘hierarchy of waste’ defined by the EU Waste Framework Directive, waste disposal to landfill represents the least desirable option.Considering the MBT process, the input component is a Municipal Solid Waste (MSW) and output components consist of Refuse Derived Fuel (RDF), compost and possibly the materials suitable for recycling.The quality of output components depends on the input waste composition.More efficient primary waste separation decreases capacity and complexity of MBT facilities.RDF offers possibility of energy recovery from the part of such separated fractions.MBT technology does not solve the problem of harmful substances residual in MSW narrowing the application of compost obtained by the biological treatment and requiring additional treatment of flue gases from RDF combustion. Comparison of the composition of untreated MSW and RDF obtained by the MBT process is also presented in the paper.

Improvements of dyeing processes by heat recovery

Publisher Summary This chapter discusses improvements of dyeing processes by heat recovery. ABSTRACT Heat recovery from warm technological effluents in dyeing processes is presented. The analysis in the chapter is based on real process data from some factories of the Croatian textile industry branch. The effluents flow out periodically at different time intervals and the recuperator is applied in a system with two accumulation water tanks, one for polluted warmed effluent and another for warmed fresh water. From the analyzed data, evidently heat recovery results with energy cost savings, as well as with technological process time savings and with environmental benefits through lowering the temperature of waste water. The economical advantages are in reduced steam, water and drainage expenditure, and also in shorter duration of the process. Environmental benefits are lower thermal and chemical contamination and prerequisite for pretreatment of effluents. Technological preferences are the reduced temperature shocks on working material and shorter duration of the dyeing process. All these improvements have to be adequately valorized when the investment in the proposed heat recovery is analyzed.

Investigation of solar declination

A new expression for solar declination angle calculation has been developed using data for four years of periodical changes. The accuracy of the proposed formula related to astronomical ephemerides is obtained using the method of the minimum sum of square errors. The calculated values vary between 1.285 and 2.776° for the selected whole year while the value for four years is 6.686°. The mean bias error differs between −0.009 and −0.050°. The standard deviation is 0.128 and 0.181, respectively. The equation proposed in this study can easily be used for solar declination computation for each day of a selected year.