Pyrolysis Of Refuse-derived Fuel Research Articles

Benefits from co-pyrolysis of biomass and refuse derived fuel for biofuels production: Experimental investigations

The application of renewable fuels and waste for energy production is crucial environmentally and economically. Co-pyrolysis of biomass and refuse derived fuel (RDF) offers a promising pathway for valuable products that combine various benefits including enhanced energy recovery, waste valorisation, improved product quality, and environmental sustainability. Consideration of specific feedstocks and optimization of process parameters are necessary to maximise the efficiency and effectiveness of the co-pyrolysis process. This work presents investigations of the co-pyrolysis process of lignocellulosic biomass wastes (rye straw and agriculture grass) and RDF. These biomasses ensure efficient decomposition. The RDF, high in carbon (78.5 %) and hydrogen (11.8 %), was predominantly plastic based. Based on Py-GC-MS studies at 600 °C, it was observed that the addition of RDF to biomass caused a significant decrease in the share of organic oxygen compounds among the released decomposition products. Laboratory tests were performed in a fixed-bed reactor for raw biomass and RDF and 1:1 and 3:1 biomass to RDF mass ratio. The results demonstrated that the yield of char production decreased with the addition of RDF, which promoted the bio-oil yield. Despite, RDF pyrolysis meets problems, it was proved that co-pyrolysis of biomass and RDF is a good solution for their utilization.

Pyrolysis of plastics-free refuse derived fuel derived from municipal solid waste and combustion of the char products in lab and pilot scales: A comparative study

Pyrolysis of refuse derived fuel (RDF) has great potential for energy recovery from municipal solid waste (MSW), while chlorine-related plastics issue was one major barrier for scale up. After screening out plastics, the RDF pyrolysis and char products combustion were evaluated in lab and pilot scales. Thermogravimetry with Fourier-transform infrared spectroscopy results suggest that the main RDF pyrolysis reaction occurred in 190–410 °C, involving decomposition, decarboxylation, demethylation, and dehydration reactions, with CO2, CH4, H2O, CO, and organic compounds as the main gaseous products. Impacts of temperature and residence time on char yield and proximate composition were evaluated in lab, and a lower temperature was favored. The pilot-scale char had a comparable proximate composition to the lab-scale ones, but a lower heating value, lower H/C ratio, higher O/C ratio, which may due to different dominant reaction pathways during pyrolysis: apparent demethanation versus dehydration. Thermogravimetry data infers that the combustion performance of pilot-scale char, including combustion stage, weight loss, and kinetic parameters, were close to chars made in lab. Pilot-scale combustion tests show relief of flue gas pollution after upgrading RDF to char, while particulate matter and heavy metals were still main concerns. Lab- and pilot-scale investigations highlight scale up of plastics-free RDF pyrolysis and combustion as a promising and economic alternative for materials and energy recoveries from MSW.

Possibilities of RDF Pyrolysis Products Utilization in the Face of the Energy Crisis

The main goal of the study was to assess the possibility of practical use of products of pyrolysis of refuse-derived fuel (RDF), i.e., pyrolysis gas, biochar and pyrolysis oil, as an alternative to standard fossil fuels. The subject matter of the paper reaches out to the challenges faced by the global economy, not only in the context of the energy crisis, but also in the context of the energy transformation currently beginning in Europe. The increase in fuel and energy prices prompts countries to look for alternative solutions to Russian minerals. At the same time, the growing amount of municipal waste forces the implementation of solutions based on energy recovery (the amount of municipal waste per EU inhabitant in 2021 is 530 kg). One such solution is pyrolysis of RDF, i.e., fuels produced from the over-sieve fraction of municipal waste. In Poland, insufficient processing capacity of thermal waste conversion plants has led to significant surpluses of RDF (1.2 million Mg of undeveloped RDF in Poland in 2021). RDF, due to their high calorific value, can be a valuable energy resource (16–18 MJ/k). This issue is analyzed in this study.

Pyrolysis of RDF and Catalytic Decomposition of the Produced Tar in a Char Bed Secondary Reactor as an Efficient Source of Syngas

One of the technical limitations of refuse-derived fuel (RDF) pyrolysis is the high content of tar in its gas products. In order to resolve this problem, a two-stage RDF pyrolysis with a catalyst based on char from RDF pyrolysis is proposed. This paper presents the results of municipal waste pyrolysis beginning in an oven heated to 480 °C and ending with catalytic tar cracking carried out in the temperature range from 800 to 1000 °C. Thermal and catalytic pyrolysis with a char catalyst containing a minimum of 6% Fe resulted in increases in the CO and H2 contents in gas products and decreases in CO2 and CH4. At 1000 °C, the mass ratio of gaseous products to liquids was greater than 6. The residence time of the gases in the catalytic zone was about 3–5 s. The reactor was a good source of hydrogen and carbon monoxide.

The Prediction of Calorific Value of Carbonized Solid Fuel Produced from Refuse-Derived Fuel in the Low-Temperature Pyrolysis in CO2.

The decrease in the calorific value of refuse-derived fuel (RDF) is an unintended outcome of the progress made toward more sustainable waste management. Plastics and paper separation and recycling leads to the overall decrease in waste’s calorific value, further limiting its applicability for thermal treatment. Pyrolysis has been proposed to densify energy in RDF and generate carbonized solid fuel (CSF). The challenge is that the feedstock composition of RDF is variable and site-specific. Therefore, the optimal pyrolysis conditions have to be established every time, depending on feedstock composition. In this research, we developed a model to predict the higher heating value (HHV) of the RDF composed of eight morphological refuse groups after low-temperature pyrolysis in CO2 (300–500 °C and 60 min) into CSF. The model considers cardboard, fabric, kitchen waste, paper, plastic, rubber, PAP/AL/PE (paper/aluminum/polyethylene) composite packaging pack, and wood, pyrolysis temperature, and residence time. The determination coefficients (R2) and Akaike information criteria were used for selecting the best model among four mathematical functions: (I) linear, (II) second-order polynomial, (III) factorial regression, and (IV) quadratic regression. For each RDF waste component, among these four models, the one best fitted to the experimental data was chosen; then, these models were integrated into the general model that predicts the HHV of CSF from the blends of RDF. The general model was validated experimentally by the application to the RDF blends. The validation revealed that the model explains 70–75% CSF HHV data variability. The results show that the optimal pyrolysis conditions depend on the most abundant waste in the waste mixture. High-quality CSF can be obtained from wastes such as paper, carton, plastic, and rubber when processed at relatively low temperatures (300 °C), whereas wastes such as fabrics and wood require higher temperatures (500 °C). The developed model showed that it is possible to achieve the CSF with the highest HHV value by optimizing the pyrolysis of RDF with the process temperature, residence time, and feedstock blends pretreatment.

Pyrolysis characteristics and mechanism of hydrocarbon compounds for RDF

With the help of pyrolysis gas chromatography–mass spectrometry (Py-GC-MS), high resolution thermogravimetric instrument and CHONS elemental analyzer, the pyrolysis products of refuse-derived fuel (RDF) in different months in one year are studied in this article. And the three kinds of RDF are denoted as A, B and C, respectively. High resolution thermogravimetric tests showed that obvious chemical reactions took place for RDF samples in the temperature ranges of 433–623 K, 623–773 K and 773–1173 K. RDF samples were tested by Py-GC-MS under 623 K, 773 K or 1173 K while He was as the balance gas, and the qualitative and semi-quantitative analysis results were obtained by introducing pyrolysis products into gas chromatography–mass spectrometry. According to the Py-GC-MS tests, the kinds and contents of pyrolysis products increased with the rising of the temperature, and RDF pyrolysis finished prior to 1173 K. Primary discussion for pyrolysis mechanism is progressed according to main pyrolysis products and the change of their relative contents, which can be used to provide the significant fundamental research of homogeneous reduction for NOx removal.

Technological and economic aspect of Refuse Derived Fuel pyrolysis

Abstract The article presents the results of RDF (Refuse Derived Fuel) examination in order to use it for energy purpose. RDF material was subjected to thermogravimetric analysis. The TGA analysis confirmed the multi-component nature of tested material. It also indicated that the mixture consists of a minimum of 2 types of materials: biomass and thermoplastic polymers. The pyrolysis was conducted as a batch process with the use of a processing furnace supplied by the IZO Company. RDF sample was pyrolysed under 900 °C in a nitrogen atmosphere. Obtained char and gaseous sample, as well as raw material, were subjected to elemental and gas chromatographic analysis. Furthermore, using ANSYS CHEMKIN-PRO software, numerical simulations of these samples were conducted. Based on the results of composition of pyrolysis gas, the numerical model was validated. Next, modelling of chemical composition of gas from RDF pyrolysis for a pilot installation working in Poland was performed. In addition, the evaluation of the investment costs for the exemplary installation for the thermal conversion of RDF using pyrolysis was made. For this purpose, dynamic methods of investment project assessment were used, which take into account the distribution of anticipated revenues and expenses related to a given investment project over time.

Catalytic gasification of refuse-derived fuel in a two-stage laboratory scale pyrolysis/gasification unit with catalyst based on clay minerals

Municipal solid waste (MSW) disposal is a serious environmental issue requiring immediate solution and good waste management strategy. Mechanical-biological treatment (MBT) plants offer the opportunity to reduce the amount of MSW that is, otherwise, disposed of in landfills. Up to 40% of MSW is converted to waste fuel, also called refuse-derived fuel (RDF). Gasification is a promising alternative of RDF processing. It can be defined as high temperature treatment of the feedstock with lower than stoichiometric amount of oxygen resulting mainly in a gaseous product (syngas). High hydrogen content, specific ratio of H2/CO, and low tar content are important parameters of syngas for its application in both energy production and chemical synthesis. Reduction of tar content in syngas can be achieved by catalytic tar cracking. In this work, a catalyst prepared from natural clay was characterised by thermogravimetric, specific surface area, X-ray diffraction, X-ray fluorescence and scanning electron microscopy (SEM) analyses. Catalyst activity was tested in two reactions, namely in decomposition of model tar constituent, p-xylene, and in cracking of tar produced in RDF gasification experiments. Influence of the reaction temperature and the amount of catalyst on the p-xylene conversion and products’ distribution was studied. The results proved high catalytic activity of the prepared catalyst in the decomposition of p-xylene. Coupled RDF pyrolysis and the produced volatiles gasification experiments were carried out in a two-stage laboratory scale reactor using a bed of tar cracking catalyst in the second stage. Tar decomposition experiments were carried out at the reactor temperatures of 700–850 °C applying different amounts of catalyst (0.75 g, 1 g, 1.25 g, 1.5 g, 2 g and 4 g) per 1 g of pyrolised RDF. Results indicate that the presence of catalyst had significant effect on both tar cracking efficiency and gas composition. Loss of the catalyst specific surface area was observed when the experiments were carried out at temperatures exceeding 800 °C.

Catalytic Co-Pyrolysis of Kraft Lignin with Refuse-Derived Fuels Using Ni-Loaded ZSM-5 Type Catalysts

The catalytic co-pyrolysis (CCP) of Kraft lignin (KL) with refuse-derived fuels (RDF) over HZSM-5, Ni/HZSM-5, and NiDHZSM-5 (Ni/desilicated HZSM-5) was carried out using pyrolyzer-gas chromatography/mass spectrometry (Py-GC/MS) to determine the effects of the nickel loading, desilication of HZSM-5, and co-pyrolysis of KL with RDF. The catalysts were characterized by Brunauer–Emmett–Teller surface area, X-ray diffraction, and NH3-temperature programed desorption. The nickel-impregnated catalyst improved the catalytic upgrading efficiency and increased the aromatic hydrocarbon production. Compared to KL, the catalytic pyrolysis of RDF produced larger amounts of aromatic hydrocarbons due to the higher H/Ceff ratio. The CCP of KL with RDF enhanced the production of aromatic hydrocarbons by the synergistic effect of hydrogen rich feedstock co-feeding. In particular, Ni/DHZSM-5 showed higher aromatic hydrocarbon formation owing to its higher acidity and mesoporosity.

RDF pyrolysis by TG-FTIR and Py-GC/MS and combustion in a double furnaces reactor

With the increasing depletion of fossil energy, the refuse-derived fuel (RDF) as an unavoidable by-product of human activities has been used as an alternative fuel in the precalciner cement kilns. Since the RDF combustion also brings the problems of NOx pollution, it is quite important to find ways to lower the NOx emission during RDF combustion in the precalciner. The pyrolysis characteristics and products of RDF were studied by TG-FTIR and Py-GC/MS. From TG-FITR and Py-GC/MS tests, various carboxylic acids and alkenes formed with NOx released at the RDF pyrolysis process at 200–550 °C. By simulating the temperature (700 °C, 800 °C and 900 °C) and O2 (12%, 14%, 16%, 18% and 21%) environment of the precalciner using a double furnaces reactor, the combustion processes and NOx formation characteristics of RDF combustion were studied. The results showed that the volatile-N was the dominant reactant source of fuel NOx during RDF combustion. The fuel-N conversion and NOx emission yield showed a continuous decreasing trend with temperature increasing from 700 to 900 °C. The fuel-N conversion and NOx emission yield showed a slight increasing trend with the oxygen concentration increase, and the optimum oxygen concentration for RDF combustion was 14%. In this study, the optimum temperature was 900 °C and oxygen concentration was 14% for de-NOx in the precalciner.

Kinetic modelling of RDF pyrolysis: Model-fitting and model-free approaches

In this study, refuse derived fuel (RDF) was selected as solid fuel and it was pyrolyzed in a thermal analyzer from room temperature to 900°C at heating rates of 5, 10, 20, and 50°C/min in N2 atmosphere. The obtained thermal data was used to calculate the kinetic parameters using Coats-Redfern, Friedman, Flylnn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS) methods. As a result of Coats-Redfern model, decomposition process was assumed to be four independent reactions with different reaction orders. On the other hand, model free methods demonstrated that activation energy trend had similarities for the reaction progresses of 0.1, 0.2–0.7 and 0.8–0.9. The average activation energies were found between 73–161kJ/mol and it is possible to say that FWO and KAS models produced closer results to the average activation energies compared to Friedman model. Experimental studies showed that RDF may be a sustainable and promising feedstock for alternative processes in terms of waste management strategies.

Activated carbon production from RDF and its use for dioxin removal from flue gas of waste incinerators

Aims: The aims of this study were to produce activated carbon from refuse derived fuel (RDF) and to examine its efficiency in dioxins and furans (PCDD/F) removal for application in the adsorptive processes of waste incineration. Materials and Methods: In the present study the RDF was carbonized at 600°C to produce char and the char was then steam activated at 900°C to generate activated carbon (AC). The efficiency of the produced AC in PCDD/F removal from simulated flue gas was investigated using a bench scale static-bed reactor. Experiments were conducted under flue gas stream at 275°C using a standard flyash (BCR-490) as a source of PCDD/F. The PCDD/F content of the exhaust gas was trapped by XAD-II resin, and after extraction and clean-up processes, were analyzed using a GC coupled with a triple quadrupole mass spectrophotometer (MS). Results: The results showed an overall reduction of 85% and 43% in the flue gas concentration of PCDD and PCDF, respectively, which compared favourably with a commercial AC. In addition, reduction was varied throughout the congener groups of these compounds. Conclusions: The AC derived from the pyrolysis of RDF therefore shows potential as a control material for dioxins and furans in waste combustion process.

Pyrolysis Characteristics of Refuse Derived Fuel in a Pilot-Scale Unit

Various compositions of refuse derived fuel (RDF), and the differences in its thermal degradation behavior, make the modeling, design, and operation of thermal conversion systems a challenge. In this paper, the pyrolysis characteristics of RDF in a pilot-scale unit were investigated to determine the operating conditions for a 30 kg/h scale pyrolysis melting incinerator. The gaseous volatile and tar components in the pyrolysis products were measured using gas chromatography (GC). The morphology of the char derived from RDF pyrolysis was observed using scanning electron microscopy (SEM). The Arrhenius parameters and prediction of the pyrolysis time were obtained from isothermal kinetic results. The results of the kinetic analysis indicated that the first-order reaction model was reliable for predicting the conversion of RDF pyrolysis. A reasonable thermal decomposition scheme of RDF pyrolysis has also been discussed.

Reactivity in Oxygen and Carbon Dioxide of Char Formed in the Pyrolysis of Refuse-Derived Fuel

The reactivity in oxygen and carbon dioxide of chars obtained from the pyrolysis of a refuse-derived fuel (RDF) was investigated. RDF chars were obtained in a fixed-bed pyrolysis reactor at low heating rates (60 °C/min) and temperatures between 500 and 800 °C. The heterogeneous gasification kinetics of the chars were studied using thermogravimetric methods and were compared to data available in the literature. The RDF chars were found to have a reactivity quite similar to that of chars obtained from municipal solid wastes and wood, but higher than that of graphite of about 5 orders of magnitude in oxygen. Raising the final temperature of the pyrolysis process from 500 to 800 °C resulted in the decrease of the H/C ratio and in a significantly lower reactivity in oxygen of the char.

Pyrolysis kinetics of refuse-derived fuel

Refuse-derived fuel (RDF) was mechanically separated from municipal solid waste (MSW) in a 300 TPD (tons per day) waste pretreatment plant. Pyrolysis of the RDF produced approximately 28% of oils, and 30% of noncondensible hydrocarbon gases and 42% of solid residues at 773 K. Thermal gravimetric analysis (TGA) techniques were used in quantitative prediction of the RDF pyrolysis rate. The global pyrolysis reaction rate was calculated from key component fractions (paper, LDPE, HDPE, PS, and PVC) of RDF using the weighed sum method. Good agreement was found in pyrolysis kinetics between RDF itself and the weighed sum method of the plastic components in RDF. Pyrolysis of RDF in the fixed-bed reactor also had a similar result. This approach allows one to easily account for RDF composition variations, thus rendering the model more generally valid.

Devolatilization of Pulverized Refuse-Derived Fuel.

This study is attempt to burn pulverized Refuse-Derived Fuel (RDF) made from municipal solid waste (MSW) for thermally recycling of waste resources. RDF has a large content of volatile matter in weight in proximate analysis, which under devolatilization contributes significantly to the combustion behavior of RDF. The devolatilization properties of both RDF and its constituent materials such as plastics (polypropylene, polystyrene), fiber (nylon) and paper (newspaper) were observed by the thermogravimetry and differential thermal analysis (TG/DTA) to obtain fundamental data of RDF combustion. The thermogravimetric (TG/DTA) analyzer was used to measure weight loss and temperature difference of the selected sample components. The data of TG/DTA were obtained by changing the heating rates under the atmospheric condition of both nitrogen gas and air. It was observed that the weight of plastics and fiber decreased monotonously, however, the weight of RDF decreased under two or three stages with endothermic reaction during pyrolysis of RDF, and with exothermic reaction during combustion of RDF. This results indicate that the paper included in the RDF burns first at a lower temperature and then the constituent materials such as plastics and fibers burn at a higher temperature. The TG data obtained at some heating rates have been arranged in terms of Arrhenius plots versus 1/T for each sample in order to obtain the empirical activation energy and the frequency factor. The calculated weight loss using their empirical values have showed good agreement with the experimental results.

Modeling and Experimental Verification of Physical and Chemical Processes during Pyrolysis of a Refuse-Derived Fuel

A model for refuse-derived fuel (RDF) conventional pyrolysis in a fixed-bed reactor is presented. The model investigates the influence of the heat- and mass-transfer processes on the pyrolysis product yields. Solid degradation reactions have been modeled by assuming that the interactions between the main RDF components during pyrolysis are negligible and that the RDF pyrolysis behavior may be considered as the sum of the separate behaviors of “primary reacting species”. The model accounts for conductive and convective heat transfer within the solid matrix and secondary tar-cracking reactions, as well as for variability in physical properties and in the void fraction of the pyrolyzing material. Quite good agreement was found between model results and experimental data obtained for conventional pyrolysis of a RDF in a laboratory-scale fixed-bed reactor. The model is able to predict the temperature transients, the rate of gas generation, and the product final yields during conventional pyrolysis of RDF.

A Fundamental Study on Conventional Pyrolysis of a Refuse-Derived Fuel

The pyrolysis behavior of a refuse-derived fuel (RDF) under heating conditions typical of conventional pyrolysis processes was investigated. Thermogravimetric analysis and differential scanning calorimetry were performed on RDF and on some materials which have been considered “key components’’ of the thermal degradation of RDF. The product fractions obtained by RDF pyrolysis runs in a laboratory-scale fued bed reactor, at temperatures between 500 and 900 “C, were identified and characterized by different experimental techniques, including gas chromatographic analysis of gaseous products, ultimate analysis, scanning electron microscopy and internal surface area measurements of char. Gas, tar, and char global yields were determined as a function of reactor temperature. The influence of gas-phase secondary tar-cracking reactions on final gas composition was investigated. Overall kinetic parameters obtained by a simple kinetic model are compared to literature data.