This paper presents the results of the study on emission characteristics of pollutants resulting from combustion process of composite alternative fuels for use in the processes of pyrometallurgy of copper as an alternative fuel to currently used coke breeze. These fuels are mainly based on waste carrier of “C” element, and the composition of the fuel is modelled in order to obtain the appropriate energy and emission parameters as well as strength parameters. These studies confirmed the possibility of using composite fuels as an alternative reducing agent as well as an energy carrier in the processes of pyrometallurgy of copper

J. Łabaj

M. Jodkowski

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44  METALURGIJA 55 (2016) 1, 44-46J. ŁABAJ, M. JODKOWSKIEMISSION OF POLLUTANTS FROM THE COMBUSTION OF COMPOSITE FUELS BY METALLURGICAL PROCESSESReceived – Primljeno: 2015-01-25Accepted – Prihvaćeno: 2015-07-25Preliminary Note – Prethodno priopćenjeISSN 0543-5846METABK 55(1) 44-46 (2016)UDC – UDK 669.011.66-9:622.62.66.74:62.004.8=111J. Łabaj - Silesian University of Technology, Katowice, Poland.M. Jodkowski - Silesian University of Technology, Gliwice, Poland.This paper presents the results of the study on emission characteristics of pollutants resulting from combustion pro-cess of composite alternative fuels for use in the processes of pyrometallurgy of copper as an alternative fuel to cur-rently used coke breeze. These fuels are mainly based on waste carrier of “C” element, and the composition of the fuel is modelled in order to obtain the appropriate energy and emission parameters as well as strength parameters. These studies confirmed the possibility of using composite fuels as an alternative reducing agent as well as an energy car-rier in the processes of pyrometallurgy of copper.Key words: metallurgical process, alternative fuels, emission, coal, waste materialsINTRODUCTIONFine tailings produced as a result of hard coal benefi-ciation process and its preparation, not so long ago re-garded as useless materials, are gaining more and more often value as minerals. The most common method of their industrial development is the production of alterna-tive fuels for energy. Increasingly, intense research is be-ing conducted on the possibility of using them as carbo-naceous materials in metallurgical processes, e.g. in the iron ore sintering process, in the pyrometallurgical pro-cesses for the preparation of copper or in the process of recycling of metal-bearing materials [1 – 4]. The possibil-ity of using these waste carbonaceous materials in metal-lurgical processes depends on a number of factors, the most important of which include: chemical composition, calorific value (that depending on the chemical composi-tion of the fuel), granulation and shape, strength charac-teristics as well as emission characteristics [5 – 12].The results of the study on the emission of pollutants from the combustion of a composite formed fuel for use in pyrometallurgical processes of copper as an alternative fuel for currently used coke breeze are shown below.MATERIALSThe parameters of fuels used in this study are shown in Table 1.RESEARCH METHODOLOGYThe combustion process was carried out in the boiler equipped with an automatic fuel charge with retort burner and in the boiler with manual fuel charge, re-Table 1 Characteristics of fuels combust during the testfuelno.graining/ mmcompositionof dry masscalorifi c value /MJ·kg-11 pellet  12L = 20 ÷ 3067 % fi ne coal*)30 % fi ne brown coal3 % binder26,712 pellet  14L = 20 ÷ 3015  % fi ne coal*)68  % breeze coke15  % fi ne brown coal2 % binder28,623 pellet  20L = 30 ÷ 3568  % fi ne coal*)30  % coke dust2  % binder27,954 pellet  20L = 30 ÷ 3578  % fi ne coal*)20  % fi ne brown coal2  % binder27,90*) product of flotationspectively. The flue probe was installed in the flue pipe for combustion gas sampling directing to the aspiration system and then into the combustion gas analysers. The water-circulating pump was used to circulate water in the boiler. The heat collection system consisted of a heating coil with a power rating of 25 kW and a heat exchanger that worked as stabilizing system of heat re-moval from the boiler. The combustion gas analyser consists of two devices operating in parallel: Gasmet ™ DX 4 000 (Gasmet Technologies Inc.) and OXYMAT 61 (Siemens). Gasmet ™ DX 4 000 is a spectroscopic analyzer using Fourier Transform Infrared (FTIR) spec-troscopy. Measuring cell works at a temperature of 180 °C, whereby the gas components are measured in the gas phase during the measurement. OXYMAT 61 was used to measure the concentration of oxygen in the combus-tion gas. The OXYMAT 61 measures oxygen using the paramagnetic alternating pressure method in range 0 to 100 % of O2. Both these devices were connected to the computer and the results were archived and processed using Calcmet™ Standard (version 11.117) software.45J. ŁABAJ et al.: EMISSION OF POLLUTANTS FROM THE COMBUSTION OF COMPOSITE FUELS BY METALLURGICAL...METALURGIJA 55 (2016) 1, 44-46STUDY RESULTS AND DISCUSSIONIn this study the measurements of energy and emis-sion parameters of four types of fuels that differ in both granulation and composition were carried out (Table 1). The study was conducted in two types of boilers, i.e. boiler equipped with an automatic fuel charge and boil-er with a manual fuel charge. During the study combus-tion gas composition measurements were performed, i.e. the concentration of CO, NO, N2O, NO2, SO2, NH3, HCl, CH4, C2H6, C2H4, C2H2, CHOH as well as the per-centage of O2, CO2 and water vapour were determined.Table 2 summarizes the mean values of concentra-tions of gaseous components emitted during the com-bustion processes of composite solid fuels. In contrast, Figures 1 - 4 show the concentrations of gaseous com-ponents emitted during the combustion processes of composite solid fuels.An analysis of the obtained measurement data shows that:1. The combustion of fuel no. 1 produced the best en-ergy and emission parameters. This fuel was burned in the boiler equipped with an automatic fuel charge at stable operating conditions. The resulting boiler efficiency and average capacity were 62 % and 21,17 kW, respectively.Table 2  Statement of researches composite fuels characteristicfuel no. 1 2 3 4boiler auto manual manual manualfl ue gas componentunit mean concentrationH2O (g) % obj. 2,29 0,47 3,84 0,69CO2 % obj. 3,57 4,00 5,57 4,49O2 % obj. 15,50 13,04 15,31 16,81CO ppm 1 181,0 20 959,3 4 243,55 6 924,67N2O ppm 0,58 1,60 0,95 0,95NO ppm 363,00 284,57 365,92 321,89SO2 ppm 354,11 305,45 362,88 305,19NO2 ppm 0 3,26 0,75 1,82NH3 ppm 2,95 3,80 0 1,89HCl ppm 10,83 17,32 22,05 14,27CH4 ppm 3,83 506,80 167,88 1 031,45C2H6 ppm 2,69 200,33 44,55 109,66C2H4 ppm 6,59 55,85 36,45 102,54CHOH ppm 1,33 6,11 6,67 9,182. The study carried out for fuel no. 2 dedicated to boilers equipped with a manual fuel charge, with a dominant share of coke breeze. This study showed very negative emission characteristics of the fuel. Graph analysis revealed that in the initial period of fuel combustion approx. to 100 min. the gasification process occurs that produces water gas. This is evi-denced by the high concentrations of CH4, C2H6, C2H4 and CO and the low level of moisture content in combustion gas of 0,47 % vol and 071 % vol, re-spectively. The resulting efficiency of the boiler is at a level of about 25,2 % and the resulting average boiler capacity is 10,12 kW.Figure 1  The concentrations of the gaseous pollutants emitted during combustion of the fuel 1Figure 2  The concentrations of the gaseous pollutants emitted during combustion of the fuel 246J. ŁABAJ et al.: EMISSION OF POLLUTANTS FROM THE COMBUSTION OF COMPOSITE FUELS BY METALLURGICAL... METALURGIJA 55 (2016) 1, 44-46REFERENCES[1] M. Niesler, L. Blacha, J. Łabaj: A study on the process of fine-grained plumbiferous material agglomeration, Meta-lurgija 52 (2013) 4, 521-524.[2] M. Niesler, L. Blacha, B. Oleksiak: Application of fine-grained coke breeze fractions in the process of iron ore sintering,  Metalurgija 53 (2014) 1, 37-39.[3] J. Lipart, T. Matula, M. Niesler, L. Blacha, J. Filipczyk: Wastes from the coal-enrichment process as alternative re-ducers for lead smelting from lead-acid accmulator scrap, Metalurgija 52 (2013) 4, 493-496.[4] Y. Hosotani, N. Konno, J. Shibata, T. Sato, H. Suzuki: Technology for granulating coke breeze by centrifugal rolling type pelletizer and effect of granulated coke breeze on sinte-ring operation, ISIJ International 11 (1995) 35, 1340-1347. [5]  M.A. Elliot (Ed.): Chemistry of Coal Utilization Second Supplementary Volume, John Wiley & Sons (1981).[6]  World Book Encyclopedia, Coal, 4 World Book, Inc 4 (2011), 716-733.[7]  J.G. Singer (Ed.): Combustion: Fossil Power Systems, Combustion Engineering, Inc. (1981).[8]  D.H. Wakelin (Ed.): The Making, Shaping and Treating of Steel, eleventh ed., Ironmaking The AISE Steel Founda-tion (1999).[9]  C.R. Ward (Ed.): Coal Geology and Coal Technology, Blackwell Scientific (1984).[10]  R. Lutter, E. Irwin: Mercury in the Environment, a Volatile Problem, Environment 44 (2002) 9, 24-40.[11]  K. Kubica, M. Jewiarz, A. Szlęk, S. Werle, R. W. Mokrosz: The influence of kaolin on the straw combustion parame-ters in grate boilers, CaReTech (2011), 19-22.[12]  Perry’s Chemical Engineers’ Handbook, Seventh Edition, McGraw-Hill (1999).Note:  O. Rachowska-Siwiec is responsible for English language, Kato-wice, Poland3. In the case of fuel no. 3 having a reduced level of coke breeze to 30 %, the gasification process also occurs, however, the most of the gases are combust-ed as evidenced by reduced concentrations of CO, CH4, C2H6, C2H4 in comparison to fuel no. 2. This fuel combusts more efficiently and the boiler pro-vides the average power at 16,76 kW and efficiency of 51 %.4. Fuel No. 4 examined in the research showed similar combustion characteristics to fuel no. 2, except the lower CO concentration level, but still emission of combustible gases like CH4, C2H6, C2H4 from a boil-er was observed. The thermal efficiency of the boiler was 53 % while the average power of the boiler was 15,01 kW.SUMMARYThese energy-emission studies confirmed the possi-bility of using waste carriers of “C” element as compo-nents of composite fuels and their applications as an al-ternative reducing agent as well as an energy carrier in the processes of pyrometallurgy of copper. With the pos-sibility of influence on the composition of the composite formed fuel, it is possible to control its parameters such as the calorific value, volatile matter content, strength etc., and as a consequence its quality remains unchanged. In addition, it is possible to dedicate composite formed fuel to a particular pyrometallurgical process.Figure 4  The concentrations of the gaseous pollutants emitted during combustion of the  fuel 4Figure 3  The concentrations of the gaseous pollutants emitted during combustion of the fuel 3

Emission of pollutants from the combustion of composite fuels by metallurgical processes

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