Analýza procesu zplyňování alternativního paliva (50% odpad, 50% plasty)

The paper presents analysis of alternative fuel gasification with use of flue gas as a gasifying agent. As a result of a process syngas with combustible components (CO, H2, CH4, CnHm) was obtained. Laboratory tests were carried out to determine usability of selected alternative fuel to low-temperature gasification process. Tests were conducted in a laboratory reactor allowing to gasify a fuel sample of appx. 1 g. The experimental stand enables recording of a sample weight loss and syngas composition. The process takes place for fuel samples of a constant weight and different granulation and with a set composition of flue gas used as a gasifying agent. The aim of the laboratory research was to determine the usability of RDF fuel for indirect co-firing in power boilers and to build a knowledge base for industrial-size process by defining the process parameters: kinetics (time for fuel to remain in the reactor), recommended fuel granulation and process temperature.Článek prezentuje analýzu zplyňování alternativního paliva s využitím spalin jako zplyňovacího prostředku. Jako výsledek zplyńovacího procesu “syngas” byly definovány hořlavé složky (CO, H2, CH4, CnHm). Byly provedeny laboratorní testy pro určení použitelnosti vybraného alternativního paliva pro proces zplyňování při nízkých teplotách. Testy byly prováděny v laboratorním reaktoru, který umožnil zplyňovat vzorek paliva o hmotnosti cca. 1 g. Experimentální zařízení umožňuje zaznamenat úbytek hmotnosti vzorku a jeho složení. Proces probíhá u vzorků paliva s konstantní hmotností a s různou granulometrii a se stanoveným složením spalin použitým jako zplyňovací medium. Cílem laboratorního výzkumu bylo zjistit použitelnost paliva RDF pro nepřímé spolu-spalování v energetických kotlích a vytvořit znalostní základnu pro reálný průmyslový proces definováním parametrů procesu: kinetiky (doby setrvání paliva v reaktoru), doporučená granulometrie paliva a teploty procesu

Recommendations for the process of biomass and waste gasification in a rotary reactor

The paper presents a technology for biomass and waste gasification/pyrolysis with use of flue gas as a converting agent. This technology includes a rotary reactor that operates continuously and is integrated with a power boiler, for example WR-25 type grate boiler. Process gas (syngas) as well as possible char being a result of the process are combustible and can be recirculated to the boiler’s combustion chamber. The paper presents laboratory research of selected biomass and waste: Refuse derived fuel (RDF), wood chips, nut shells, sewage sludge, coal sludge, mixture of 50% coal sludge with 50% RDF. Basing on the laboratory research a calculation procedure was developed to determine an industrial-size process parameters. The procedure allows to calculate how much fuel can be gasified/converted in a rotary reactor and the reactor’s dimension: inner diameter Dwr and length Lr

Potassium and chlorine distributions in high temperature halloysite formed deposits

The paper presents results of investigations on KCl interaction with halloysite under high temperature conditions. Halloysite is an aluminosilicate that can be used as a fuel additive to prevent chlorine corrosion and formation of low melting corrosive deposits during combustion of biomass. It is claimed that an increase of the emission of gaseous chlorine as HCl(g) and decrease of chlorine share in the ash as result of KCl and halloysite interaction should be expected. During presented tests the mixtures of KCl and halloysite with different ratios were thermally decomposed in a muffle furnace at high temperatures of 900°C and 1100°C. Then, the analyses of potassium and chlorine contents in the formed solid residues were determined. Besides, it has been proved that halloysite addition changes the ash deposit structure as well as increases the ash fusion temperatures. This was supported by performing phase equilibrium calculations for the investigated different halloysite/KCl mixtures. The positive effects of halloysite on potassium capture while reducing chlorine content in solid residue to prevent formation of corrosive deposits have been confirmed

Studies on the effectiveness of SCR catalysts during combustion of pulverized coal

The motivation of this paper is new NOx emission regulations according to IED Directive 2010/75/EU of EU which introduce the BAT’s conclusions as binding. The paper presents the methodology and results of research on the effectiveness of SCR catalysts during combustion of pulverised coal in a model furnace installed at the Institute of Power Engineering and Turbomachinery of the Silesian University of Technology (IPET). The aim of the research was to search for catalysts that could be placed in a regenerative rotary air heater - RAH-SCR. Two catalysts were tested: a commercial plate-type based on V2O5 and a prototype ceramic based on platinum. Presented results of investigation demonstrate a potentially high efficiency of RAH-SCR installations which can meet new environmental regulations of NOx emission. The highest NOx reduction efficiency (92.87%) was obtained for an industrial catalyst at 329°C, from about 436.3 to 31.1 mg/m3 as NO2 @ 6%O2 to 31,1. At lower temperature, 260°C maximum efficiency of NOx reduction does not exceed 60%, from 440,0 to 169,6 mg/m3. The placement of the catalyst in the RAH can also be a support for SNCR installations due to the increase in DeNOx efficiency and reduction of NH3 slip

Significance and Challenges of Poultry Litter and Cattle Manure as Sustainable Fuels: A Review

Growing animal production results in a significant amount of waste, composed of manure, bedding, feed, feathers, etc., whose safe and cost-effective disposal becomes a troublesome challenge. The literature review points out that the higher heating value (HHV) of animal-origin waste reaches 19 MJ/kg (dry basis), which positions it as a promising renewable energy source. Various paths of energy recovery were investigated in the literature, but the thermal processes, particularly combustion and co-combustion, were indicated as the most effective from both technical and environmental points of view. The presented study reviews the fuel characteristics, possible combustion-related challenges, and ash disposal routes of the most popular animal-origin waste: poultry litter and cow (cattle) manure with a slight sight on piggery (swine) manure. When considering animal-origin feedstock as fuel, usually only animal species is given (poultry, cattle, etc.). However, according to the analyzed literature data, this is not sufficient information. Several more factors crucially influence the fuel and ash properties of animal waste and the most vital are: the housing system, type of bedding, and farming style. Animal litter is considered a “difficult” fuel, nevertheless, it does not always cause combustion-related problems. Some analyzed feedstock feature low chlorine concentrations and high ash melting temperatures, which makes them combustion-friendly

Muły węgla kamiennego – odpad czy cenne paliwo?

W artykule zaprezentowano badania dotyczące termicznej konwersji mułu węgla kamiennego przy użyciu spalin jako czynnika konwertującego. Ideą procesu jest recyrkulacja powstałego gazu palnego (syngazu) do komory spalania kotła, z którego pobierane były spaliny. Celem badań jest określenie przydatności mułów do pośredniego spalania w kotłach energetycznych oraz opracowanie zaleceń do prowadzenia procesu w skali przemysłowej

Ammonia desorption from fly ash

The main source of ammonia in ash are residues from an unreacted NH3 from the denitrification process, either from SCR or SNCR systems. The paper discusses the standards of NH3 content in fly ash and presents the most commonly used methods of removing excess ammonia from fly ash. In the next part of the work the results of laboratory tests on NH3 desorption are presented. Desorption was performed on samples of fly ash taken from the electrostatic precipitator of real PC boiler. Removal of NH3 from the ash was carried out in a heating chamber at 130°C and 150°C and detected by an analyser equipped with a NDIR sensor. Additionally, at the temperature of 130°C, the NDIR and analytical methods were compared (in accordance with the BN-750541-05 procedure) and the measurement uncertainty of both methods was estimated

Properties of Animal-Origin Ash—A Valuable Material for Circular Economy

In the presented paper, two types of animal-origin biomass, cow dung and chicken litter, are characterized in terms of combustion-related problems and ash properties. It was found that these parameters strongly depend on the farming style. Whether it is cow dung or chicken litter, free-range raw materials are characterized by higher ash contents than industrial farming ones. Free-range samples contain chlorine at lower levels, while industrial farming samples are chlorine rich. Free-range samples are characterized by the predominant content of silica in the ash: 75.60% in cow dung and 57.11% in chicken litter, while industrial farming samples contain more calcium. Samples were classified by 11 “slagging indices” based on the ash and fuel composition to evaluate their tendencies for slagging, fouling, ash deposition and bed agglomeration. Furthermore, an assessment was made against the current EU law regulations, whether the ashes can be component materials for fertilizers. The phosphorus concentration in the investigated ashes corresponds to 4.09–23.73 wt% P2O5 and is significantly higher in industrial chicken litter samples. The concentrations of Hg, Cu, As, Ni, Cd and Pb in all samples are below the limits of the UE regulations. However, concentrations of Cr in all samples and Zn in industrial chicken litter exceed these standards

Properties of Animal-Origin Ash—A Valuable Material for Circular Economy

In the presented paper, two types of animal-origin biomass, cow dung and chicken litter, are characterized in terms of combustion-related problems and ash properties. It was found that these parameters strongly depend on the farming style. Whether it is cow dung or chicken litter, free-range raw materials are characterized by higher ash contents than industrial farming ones. Free-range samples contain chlorine at lower levels, while industrial farming samples are chlorine rich. Free-range samples are characterized by the predominant content of silica in the ash: 75.60% in cow dung and 57.11% in chicken litter, while industrial farming samples contain more calcium. Samples were classified by 11 “slagging indices” based on the ash and fuel composition to evaluate their tendencies for slagging, fouling, ash deposition and bed agglomeration. Furthermore, an assessment was made against the current EU law regulations, whether the ashes can be component materials for fertilizers. The phosphorus concentration in the investigated ashes corresponds to 4.09–23.73 wt% P2O5 and is significantly higher in industrial chicken litter samples. The concentrations of Hg, Cu, As, Ni, Cd and Pb in all samples are below the limits of the UE regulations. However, concentrations of Cr in all samples and Zn in industrial chicken litter exceed these standards

Combined NOx and NH3 Slip Reduction in a Stoker Boiler Equipped with the Hybrid SNCR + SCR System FJBS+

The application of secondary NOx control methods in medium to low-capacity furnaces is a relatively new topic on the energy market and thus requires further research. In this paper, the results of full-scale research of SNCR and hybrid SNCR + SCR methods applied into a 29 MWth solid fuel fired stoker boiler is presented. The tests were performed for a full range of boiler loads, from 33% (12 MWth) to 103% (30 MWth) of nominal load. A novel SNCR + SCR hybrid process was demonstrated based on an enhanced in-furnace SNCR installation coupled with TiO2-WO3-V2O5 catalyst, which provides extra NOx reduction and works as an excess NH3 “catcher” as well. The performance of a brand-new catalyst was evaluated in comparison to a recovered one. The emission of NOx was reduced below 180 mg NOx/Nm3 at 6% O2, with ammonia slip in flue gas below 10 mg/Nm3. Special attention was paid to the analysis of ammonia slip in combustion products: flue gas and fly ash. An innovative and cost-effective method of ammonia removal from fly ash was presented and tested. The main idea of this method is fly ash recirculation onto the grate. As a result, ammonia content in fly ash was reduced to a level below 6.1 mg/kg