Torrefaction and gasification of biomass for polygeneration: Production of biochar and producer gas at low load conditions

In this paper, a matter of biomass torrefaction and gasification is closely looked at from different points of view during low load and low equivalence ratio regime, defined as lambda = 0.08. Considering gas production, the hot gas efficiency of conversion (30%) and its energy content (4.14 MJ m(-3)) were not quite satisfying, however, this matter of fact was compensated by an interesting yield of biochar. This material was generated in 0.387 and 0.314 rates for torrefaction and torrefaction + gasification processes, respectively, which, in both cases, represents an attractive, alternative approach to the functional energy storage. It was determined that a CO2 offset of 721 kg and 660 kg could be achieved per 1 tonne of woodchips for gasification of raw woodchips and a 2-stage process with torrefaction and gasification, respectively. The measured data from both technological complexes were compared with the computational model, applying equilibrium reactions for gas components determination. In addition, the question of tar compounds contained within the producer gas, is investigated through GC-MS analysis on both qualitative and quantitative basis.Web of Science814413

Use of Hydrothermal Carbonization and Cold Atmospheric Plasma for Surface Modification of Brewer’s Spent Grain and Activated Carbon

This paper presents results that show the effect of hydrothermal carbonization and subsequent cold plasma jet treatment with helium and argon on the structure and sorption properties of a material—spent brewery grain. Treatment of activated carbon, with a cold atmospheric plasma jet, was used comparatively. The effect of activation on the pore structure of the materials was carried out by the volumetric method at low pressure (N2, 77 K). The specific surface area as well as the total pore volume, average pore size, and pore size distribution were determined using different theoretical models. A high improvement in the sorption capacity parameter was obtained for hydrochars after cold atmospheric plasma jet treatment with an increase of 7.5 times (using He) and 11.6 times (using Ar) compared with hydrochars before cold atmospheric plasma jet treatment. The increase in specific surface area was five-fold (He) and fifteen-fold (Ar). For activated carbon, such a large change was not obtained after plasma activation. Regardless of the gas used, the increase in structural parameter values was 1.1–1.3

Biocoal - Quality control and assurance

Torrefied biomass is said to have potential as a replacement for coal. One of the main goals of torrefaction is to make biomass resemble coal more in terms of its properties as a solid fuel. As a fuel, a novel fuel that is produced by thermal treatment of raw biomass, biocoal has to comply with the regulations of solid fuels from different regulatory bodies. The production regime is different in comparison to the thermally treated fuel already established on the market, such as charcoal. This might raise an issue with the bodies controlling the circulation of chemical substances in the market, such as ECHA in Europe. The aim of this paper is to recommend suitable analytical techniques in order to enable effective quality control. This is necessary if biomass of low and highly variable quality is supposed to become more uniform and turn into a commodity. Information given in many published studies seems sufficient to use of FTIR and NIR as quality control techniques. The use of NMR can be complementary but is limited due to the high cost of the analytical equipment and time-consuming sample preparation. Rapid testing techniques, such as FTIR ATR or NIR, might prove feasible for quality control of solid biofuels, such as biocoal, especially for in-house quality control purposes. This way proper quality assurance and compliance with various novel regulations, such as REACH, could be assured. Further research could be helpful, especially if results would be available in publicly available databases, such as Phyllis

Torrefied biomass fuels as a renewable alternative to coal in co-firing for power generation

This study aims to assess the torrefaction of biomass as alternative renewable energy fuel to coal during co-firing. It was evaluated that torrefaction improves biomass grindability to such an extent that it can be used in coal mills with coal in co-firing without capital intensive modification. Torrefaction of beech wood was performed on a batch scale reactor at three different temperatures (200, 250 and 300 °C) with 30 min of residence time. The chemical structural changes in torrefied biomass were investigated with binding energies and FTIR (Fourier transform infrared) analysis. Monocombustion and co-combustion tests were performed to examine the combustion behaviour regarding flue gas emissions (CO, NOx and SO2) at 0.5, 1.5 and 2.5 m distance from the burner opening along with fly ash analysis. The FTIR and binding energies showed that lignin hardly affected during light torrefaction while hemicellulosic material was significantly depleted. The Hardgrove grindability index (HGI) was calculated with three methods (DIN51742, IFK and ISO). The medium temperature torrefied biomass (MTTB) yields HGI value in the range of 32–37 that was comparable with HGI of El Cerrejon coal (36–41). A slight change in temperature enabled the torrefied beech wood to be co-milled with coal without capital intensive modification and improved grindability. Comparing the combustion behaviour of single fuels, low temperature torrefied biomass (LTTB) produces less amount of NOx (426 mg/m3), CO (0.002 mg/m3) and SO2 (2 mg/m3) as compared MTTB and raw beech wood. In the case of co-combustion, it was found that blending of coal with raw biomass does not show a stable behaviour. However, premixing of 50% of coal with 50% of torrefied biomasses (MTTB and LTTB) gives most stable behaviour and reduces NOx almost 30% and SOx up to almost 50% compared to coal. The fly ash contents analysis proved that K2O contents much decreased during co-firing of coal and torrefied fuels that could cause ash related issues during combustion of raw biomass

recowatdig

Project proposes innovative, transdisciplinary approach, by enabling an access to the potential water resources, currently neglected, i.e. water evaporated during drying of high moisture solid fermentation products

Modelowanie cfd spalania pyłu węglowego w atmosferze powietrza i oxy: powstawanie NOx i SO2

Despite the fact that alternative energy sources sector has been rapidly developed since last years, coal combustion as a major fossil-fuel energy resource (especially in Poland) will continue being a major environmental concern for the next few decades. To meet future targets for the reduction of toxic and greenhouse gases emission new combustion technologies need to be developed: pre-combustion capture, post-combustion capture, and oxy-fuel combustion. This paper deals with the air-fried and oxy-fuel coal combustion (pulverized coal) combustion, and its impact on pollutants (NOx and SO2) formation. For CFD (Computational Fluid Dynamics) modeling of media flows and coal combustion process the laboratory model of combustion reactor was applied. The material input was set based on technical-elementary analysis of pulverized coal used in experiment and sieves grain-size analysis. Boundary conditions (media flows intensities and temperatures) were set based on laboratory experimental measurements. Radiation case-sensitive WSGGM model (weighted - sum - of - gray gases model) was used for calculation. The modeling was proceed for different combustion parameters in air and OXY atmosphere in oxygen/fuel ratio variation and fuel humidity variation function.Pomimo faktu gwałtownego rozwoju sektora alternatywnych źródeł energii w ostatnich dziesięcioleciach, spalanie węgla jako najważniejszego źródła energii konwencjonalnej (w szczególności w Polsce) jest bardzo istotnym zagadnieniem w aspekcie ochrony i inżynierii środowiska. Nowe wyzwania w zakresie obniżania emisji związków toksycznych, a także gazów cieplarnianych wymuszają rozwój w zakresie innowacyjnych technologii spalania węgla: pierwotnych (na etapie substratów) oraz wtórnych (na etapie produktów), a także modyfikacji procesu spalania (atmosfera OXY). W artykule przedstawiono zagadnienie formowania się zanieczyszczeń (NOx oraz SO2) powstających podczas procesu spalania pyłu węglowego w atmosferze powietrza oraz atmosferze OXY. Do obliczeń metodą CFD (przepływu i spalania mieszanki powietrzno-węglowej wykorzystano model laboratoryjnego pieca opadowego. Jako warunki brzegowe do obliczeń zastosowano wyniki analiz techniczno-elementarnych pyłu węglowego, przedziały frakcyjne cząstek ustalono na podstawie analizy sitowej. Warunki brzegowe (temperaturę pieca, doprowadzanego powietrza oraz paliwa, natężenia przepływu powietrza pierwotnego i wtórnego) ustalono na podstawie pomiarów rzeczywistych w warunkach laboratoryjnych. W celu zamodelowania spalania z uwzględnieniem radiacji wykorzystano model WSGGM (weighted-sum-of-gray-gases model). Obliczenia z uwzględnieniem radiacji oraz powstawania zanieczyszczeń NOx i SO2 prowadzono dla warunków spalania w powietrzu oraz przyjęto zróżnicowane atmosfery OXY. Obliczenia prowadzono w funkcji wartości współczynnika lambda oraz dla różnych wartości wilgotności paliwa

Ocena skuteczności i energochłonności procesu suszenia w suszarni fluidyzacyjnej i taśmowej

W pracy zawarto wyniki eksperymentalne badań nad efektywnością procesu suszenia węgla brunatnego w dwóch typach suszarek pilotowych, tj. suszarni fluidyzacyjnej i suszarni taśmowej. Opracowanie efektywnej metody suszenia węgla brunatnego, jak i biomasy, stanowi wyzwanie i konieczność ze względu na poprawę sprawności jednostek opalanych takim paliwem i redukcje emisji CO2. W instalacjach suszących jako czynnika suszącego używano dla suszarni fluidyzacyjnej powietrza, dla suszarni taśmowej spalin. Badania eksperymentalne przeprowadzono dla węgla brunatnego z kopalni Turów. Testy suszenia wykonano dla różnych temperatur czynnika suszącego i dla różnych strumieni czynnika suszącego. Wydajność suszarek węgla mokrego wynosiła ok. 100 kg/h. Oceniano skuteczność suszenia i wydatek energetyczny na usuniecie kg wody z węgla

Zastosowanie numerycznej mechaniki płynów w modelowaniu spalania węgla w atmosferze powietrza i oxy

Despite the fact that alternative energy sources sector has been rapidly developed since last years, coal combustion as a major fossil-fuel energy resource (especially in Poland) will continue being a major environmental concern for the next few decades. To meet future targets for the reduction of toxic and greenhouse gases emission new combustion technologies need to be developed: pre-combustion capture, post-combustion capture, and oxy-fuel combustion (the process of burning a fuel using pure oxygen instead of air as the primary oxidant). This paper deals with the air-fried and oxy-fuel hard and brown coal combustion (pulverized coal) combustion, and its impact on pollutants (NOx and SO2) formation. For CFD modeling of media flows and hard and brown coal combustion process the laboratory model of combustion reactor was applied. The material input was set based on technical-elementary analysis of pulverized coal used in experiment and sieves grain-size analysis. Boundary conditions (media flows intensities and temperatures). was set based on laboratory experimental measurements. Radiation case-sensitive WSGGM model (weighted – sum – of – gray – gases model) was used for calculation. The modeling was proceed for different combustion parameters in air and OXY atmosphere in oxygen/fuel ratio variation and fuel humidity variation function.Pomimo faktu gwałtownego rozwoju sektora alternatywnych źródeł energii w ostatnich dziesięcioleciach, spalanie węgla jako najważniejszego źródła energii konwencjonalnej (w szczególności w Polsce) jest bardzo istotnym zagadnieniem w aspekcie ochrony i inżynierii środowiska. Nowe wyzwania w zakresie obniżania emisji związków toksycznych, a także gazów cieplarnianych wymuszają rozwój w zakresie innowacyjnych technologii spalania węgla: pierwotnych (na etapie substratów) oraz wtórnych (na etapie produktów), a także modyfikacji procesu spalania (atmosfera OXY). W artykule zajęto się zagadnieniem formowania się zanieczyszczeń (NOx oraz SO2) powstających podczas procesu spalania pyłu węgla kamiennego i brunatnego w atmosferze powietrza oraz atmosferze OXY. Do obliczeń CFD przepływu i spalania mieszanki powietrzno-węglowej wykorzystano model laboratoryjnego pieca opadowego. Jako warunki materiałowe do obliczeń posłużono się rzeczywistymi analizami techniczno-elementarnymi pyłu węglowego. Przedziały frakcyjne cząstek ustalono na podstawie analizy sitowej. Warunki brzegowe (temperaturę pieca, doprowadzanego powietrza oraz paliwa, natężenia przepływu powietrza pierwotnego i wtórnego) ustalono na podstawie pomiarów rzeczywistych w warunkach laboratoryjnych. W celu zamodelowania spalania z uwzględnieniem radiacji wykorzystano model WSGGM (weighted – sum – of – gray – gases model). Obliczenia z uwzględnieniem radiacji oraz powstawania zanieczyszczeń NOx i SO2 prowadzono dla warunków spalania w powietrzu oraz przyjęto różnicowane atmosfery OXY. Obliczenia prowadzono w funkcji wartości współczynnika lambda oraz dla różnych wartości wilgotności paliwa