Pyrolysis Of Municipal Solid Waste Research Articles

Formation behavior of PCDD/Fs during waste pyrolysis and incineration: Effect of temperature, calcium oxide addition, and redox atmosphere

The clean and efficient utilization of municipal solid waste (MSW) has attracted increasing concerns in recent years. Pyrolysis of MSW is one of the promising options due to the production of high-value intermediates and the inhibition of pollutants at reducing atmosphere. Herein, the formation behavior of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) during MSW pyrolysis and incineration was experimentally investigated and compared. The influence of reaction temperature, CaO addition, and redox atmosphere on PCDD/Fs formation were compared and discussed. The results showed as the pyrolysis temperature increased, the mass concentration and international toxicity equivalence quantity of PCDD/Fs initially peaked at ∼750 °C before declining. Most of the generated PCDD/Fs were concentrated in the liquid and gaseous products, accounting for ∼90% of the total. Among liquid products, octachlorodibenzo-p-dioxin (O8CDD), 2,3,4,7,8-pentachlorodibenzofuran and 1,2,3,4,6,7,8-heptachlorodibenzofuran (H7CDF) were the most crucial mass concentration contributors, while in gas products, high-chlorinated PCDD/Fs, such as O8CDD, octachlorodibenzofuran (O8CDF) and 1,2,3,4,6,7,8-H7CDF were predominant. Compared to incineration, the formation of PCDD/Fs was 7–20 times greater than that from pyrolysis. This discrepancy can be attributed to the hydrogen-rich and oxygen-deficient atmosphere during pyrolysis, which effectively inhibited the Deacon reaction and the formation of C–Cl bonds, thereby reducing the active chlorine in the system. The addition of in-situ CaO additives also decreased the active chlorine content in the system, bolstering the inhibiting of PCDD/Fs formation during MSW pyrolysis.

Study on the pyrolysis and combustion characteristics of municipal solid waste in a fixed bed

Study on the pyrolysis and combustion characteristics of municipal solid waste in a fixed bed

Analysis of Essential Features and Optimal Operational Parameters of an RF-ICP Torch for Waste Treatment Applications

Recently, plasma-based pyrolysis has gained increasing prominence as a technology in response to the growing challenges in waste disposal and the recognition of opportunities to generate valuable by-products. The efficiency of the pyrolysis process is intricately tied to the characteristics of the plasma involved, particularly the effective electron temperature (Teff) and plasma density (ne). This study aimed to conduct a comprehensive examination of the essential features and optimal operational parameters of a developed RF-ICP torch specifically designed for small-scale municipal solid waste (MSW) pyrolysis (mixture of paper and polypropylene) with the goal of controlling both the torch and the overall process. Using optical emission spectroscopy (OES), we measured plasma parameters, specifically (Teff) and (ne), while varying argon gas flow rates and RF powers. The (Teff) and (ne)were determined using the Boltzmann plot and Stark broadening, respectively. The RF torch was found to generate (ne) up to approximately 2.8×1020 cm−3 and (Teff) up to around 8200 K, with both parameters being controlled by the discharge power and gas flow rate. Additionally, a power-losing mechanism, namely the anomalous skin effect, was detected during the study, which is uncommon in atmospheric plasma discharge.

Thermodynamic Simulation of the Interaction Reaction between Copper-Based Oxygen Carrier and Acid Gases from Municipal Solid Waste Pyrolysis

To reveal the interaction reaction of copper-based oxygen carriers with acid gases during chemical looping with oxygen uncoupling of MSW pyrolysis and gasification syngas, the thermodynamic analysis is employed by HSC Chemistry. The thermodynamic simulation results show that the products of the copper-chloride interactions are solid CuCl, gaseous Cu3Cl3 (g), and CuCl (g), and no solid CuCl2 is formed. In addition, it’s found that CuCl (g) originates from the high-temperature decomposition of the complex Cu3Cl3 (g). At a sufficient amount of OC, the interaction products of copper-based OC with H2S are CuSO4, SO2, and Cu2SO4, while Cu2S and CuS disappear. Compared to HCl, H2S dominates during the competitive reaction or adsorption with copper-based oxygen carrier or CaO. Due to the capture of Cl and S in the gaseous state of Ca2+, the lattice oxygen of chlorinated or sulfated oxygen carriers can be restored, suggesting that CaO can be used as an in situ dechlorinator for CLOU. The results of this work will provide theoretical guidance for the inhibition of copper-based oxygen carriers chlorination loss and active design of multifunctional oxygen carriers.

Physical Chemistry Supports Circular Economy: Toward a Viable Use of Products from the Pyrolysis of a Refuse-Derived Fuel and Granulated Scrap Tire Rubber as Bitumen Additives

The production and maintenance of road pavements consume resources and produce wastes that are disposed of in landfills. To make more sustainable this activity, we have envisioned a method based on a circular use of residues (oil and char) from municipal solid waste pyrolysis as useful additives for producing improved asphalts and for recycling old asphalts to generate new ones, reducing at the same time the consumption of resources for the production of new road pavements and the disposal of wastes to landfills. This work aims to show the feasibility of the integration of two processes (thermal treatment of municipal solid waste on one side, and that of road pavement production on the other side) where the products deriving from waste pyrolysis become added-value materials to improve the quality of road pavements. In this contribution, we presented the effect of pyrolysis product addition on asphalt binder (bitumen) preparation and aging. Solid and liquid products, deriving from the pyrolysis of two kinds of wastes (refused derived fuel (RDF) and granulated rubber tyre waste), have been used for the preparation of asphalt binder samples. Rheological tests have been performed to determine the mechanical properties of neat asphalt binder (bitumen) and those enriched with pyrolysis derived products. Measurements to evaluate possible anti-aging effects have been also performed. The collected results indicate that char addition strengthens the overall bitumen intermolecular structure while bio-oil addition exerts a rejuvenating activity.

Pyrolysis of municipal solid waste: A kinetic study through multi-step reaction models

The present study endeavors to establish a comprehensive kinetic analysis of Municipal Solid Waste residue pyrolysis. As the sample exhibits four distinct degradation stages, it has been carried out by adopting a multi-step process behavior. Different approaches have been compared, including five isoconversional methods (Kissinger-Akahira-Sunose, Ozawa-Flynn-Wall, Starink, Friedman and Advanced integral Vyazovkin), Mathematical Deconvolution Analysis, and Independent Parallel Reaction Model. The study focuses on the two active pyrolysis steps, the first one corresponds to the biomass components between 150 and 400 °C, with the decomposition peak between 300 and 350 °C, whereas the second corresponds to the plastic fraction with temperature ranging between 400 and 520 °C. The activation energy values obtained from the different kinetic methods for both steps are estimated at 240 and 250 kJ/mol, respectively. It was observed that the biomass components degradation obeys a third-order kinetic model, while the plastic fraction follows a first-order kinetic model. The analytical pyrolysis of the two main stages allows for the identification and semi-quantification of the compounds produced during municipal solid waste pyrolysis. Through analytical pyrolysis, it has been determined that up to 64 % of hydrocarbons are produced, of which 24 % correspond to aromatic compounds. Meanwhile, 20 % of oxygenated compounds were obtained, with ketones, furans, and acids being the most predominant families.

Upgrading MSW pyrolysis oil through distillation and hydrotreatment for automobile engine applications: A short review

The demand for fossil fuel in today’s world is increasing at a higher pace with rapid population growth and industrial development. The reserve for petroleum-based fossil fuels is finite which necessitates the search for alternative fuels. Pyrolysis oil obtained from Municipal Solid Waste (MSW) has drawn the attention of many researchers because of their high heating value and similar fuel properties with commercial automobile fuel and has potential to substitute commercial diesel fuel. Nevertheless, the crude oil obtained from pyrolysis of MSW has some shortcomings such as higher viscosity and density, lower flash point and cetane index, unpleasant odor, and higher sulfur content, preventing its useability as a drop in fuel for automobiles at present. In this short review, distillation and hydrotreatment post treatment procedures, amongst many others, are discussed for improving the properties of pyrolysis crude oil. Focus has been given on waste plastic and waste automobile tire pyrolysis oils as they constitute a significant amount of MSW currently. This review reported that noticeable improvement of the properties (cetane number, flash point, viscosity, and sulphur contents) of crude pyrolysis oil (PPO or TPO) can be achieved through distillation and/or hydrotreatment, which are comparable to the properties of standard diesel.

MSW pyro-gasification using high-temperature CO2 as gasifying agent: Influence of contact mode between CO2, char and volatiles on final products

The volatiles and char derived from municipal solid waste (MSW) pyrolysis can be catalytically reformed and gasified using high-temperature CO2 (HT-CO2) as gasifying agent and char as a catalyst simultaneously to obtain high quality synthesis gas, but the reactor's design for this purpose is still a question. In this research, the contact configuration between the HT-CO2, the volatile compounds, and the char from MSW pyrolysis were studied to understand the relevant reaction behaviors and to establish guidelines for the reactor’s design. Three contact modes were designed, including: M1, where volatiles and HT-CO2 contact first, then contact the char; M2, where volatiles, CO2, and char contact simultaneously at the bottom of the char layer; and M3, where CO2 contacts with the char first, then the volatiles contact in the middle of the char layer. The temperature evolution in the char layer, the yields and properties of the resultant combustible gases, used char, and tar were investigated. Experimental results revealed that the contact mode significantly affected the levels of char gasification and volatiles' reforming. For M1, intense thermal cracking of volatiles occurred and 65.41% of the input heat of HT-CO2 was consumed for thermal cracking, resulting in substantial carbon deposition and limited energy transfer from char to the synthesis gas. While, the char contacting HT-CO2 firstly in M3 improved its catalytic activity, causing 73.33 % of the input heat utilized for gasification and reforming; as a result, the maximum synthesis gas yield of 0.71 Nm3/kgMSW and gas energy ratio of 76.3 % were obtained respectively in M3 with the lowest tar yield of 5.45 %; additionally, the used char corresponded to the highest specific surface area of 10.12 m2/g. Ultimately, M3 is constructive and recommended, and the findings of this study offer helpful guidance for the design of pyro-gasification reactors.

Experimental and mechanistic study on the enrichment of heavy metals by modified calcium oxide during MSW pyrolysis

ABSTRACT Experimental and density functional theory (DFT) calculations show that NaCl modified can promote the adsorption of heavy metals Cr, Cd, and Pb by CaO in the municipal solid waste (MSW) pyrolysis. CrCl3 (g), CdCl2 (g) and PbCl2 (g) are the main form of Cr, Cd and Pb in MSW pyrolysis gas. The DFT calculations show that the adsorption energy of NaCl modified CaO (NaCl/CaO) increased from 285.37 kJ/mol, 130.58 kJ/mol and 145.72 kJ/mol to 373.80 kJ/mol, 216.03 kJ/mol and 214.67 kJ/mol for Cr, Cd and Pb compared with CaO. Similarly, the experimental average adsorption rates increased from 43.32%, 40.13% and 25.54% to 56.42%, 46.44% and 46.22%. The bondings between CaO and CrCl3, CdCl2, PbCl2 molecules are the outermost 2p orbitals of O in CaO hybridizes with the 3d and 3p orbitals of Cr, the 5s and 4d orbitals of Cd, and the 6p and 6s orbitals of Pb. After the adsorption of NaCl, the total charge change on the CaO surface changed from 0.12e to 0.01e, and the number of electrons obtained by CrCl3, CdCl2 and PbCl2 molecules from the adsorbent increased from 0.51, 0.26 and 0.22 e to 0.94, 0.53 and 0.34 e. NaCl promoting the electron-losing ability of calcium oxide surface. Meanwhile the Cl atom of NaCl form new chemical bonds with heavy metal atoms, increasing adsorption sites of heavy metal molecules with calcium oxide. This study contributes to the adsorption of heavy metals during MSW pyrolysis by CaO and NaCl/CaO.

Thermogravimetric kinetic analysis of catalytic and non-catalytic pyrolysis of simulated municipal solid waste

Municipal solid waste (MSW) disposal through landfill and incineration represents a costly and hazardous challenge to global health, and loss of underutilised resource for the circular economy. Thermal pyrolysis of the organic components of MSW offers a scalable route to liquid fuels, but process optimisation requires deep insight into the associated thermochemistry and kinetics. Here we apply thermogravimetric analysis (TGA) and kinetic modelling to the (catalytic) pyrolysis of a model MSW feedstock comprising cellulose, sucrose, sugarcane bagasse and low-density polyethylene (LDPE). Co-pyrolysis of biomass and plastic waste, with or without Al-SBA-15, MM-Al-SBA-15 or HZSM-5 catalysts, occurs in three main stages, namely the melting and concomitant evaporation of volatiles, and subsequent decomposition of carbohydrate, then LDPE and finally lignin components. The rate of non-catalytic MSW pyrolysis increased with sample heating rates (from 20 to 120 °C /min) but had little impact on the temperature or mass loss during each stage. Catalytic pyrolysis is sensitive to the catalyst:feedstock mass ratio; increasing this ratio from 1 to 5 increased mass losses during the removal of volatiles and three subsequent decomposition stages, while lowering the temperature of LDPE decomposition. Kinetic analysis by Friedman’s isoconversional method reveals a monotonic increase in activation energy for each stage of (non-catalytic and catalytic) MSW pyrolysis. However, energy barriers for individual stages decreased with increasing catalyst:feedstock ratio and were sensitive to the catalyst type: Al-SBA-15 offers the largest decrease in barriers for carbohydrate (−86 kJ/mol) and LDPE decomposition (−92 kJ/mol), and similar promotion to HZSM-5 for lignin decomposition (∼100 kJ/mol), at the highest catalyst content. TGA is an effective tool for catalyst selection and process optimisation provided heating rates < 60 °C /min are employed, above which pyrolysis appears heat transfer limited.

Effect of biochar from municipal solid waste on mechanical and freeze–thaw properties of concrete

Global municipal solid waste (MSW) generation and cement manufacture pose catastrophic threats to the environment. Although positive impacts have been demonstrated for biochar originating from single biomass in concrete, limited studies focused on the biochar from the pyrolysis of municipal solid waste, and the freeze–thaw resistance of biochar concrete still remains unknown. This paper explored the feasibility of biochar derived from MSW at 600℃ to replace 1%-30% cement by weight in concrete. Properties of water absorption, setting time, mechanical properties and freeze–thaw resistance for the mixture systems were studied with the inspections of Scanning electron microscope (SEM), Fourier transforms infrared spectrometer (FT-IR) and X-ray diffraction (XRD). The results suggested that biochar replacement reduced the setting time of the binder system with an increase in water requirement of normal consistency. The compressive strength of concrete was increased by 9.2% with less than 5% of cement replaced. Biochar markedly improved the flexural and splitting tensile strength of concrete and thus played a beneficial role in toughness by 20% at 10% cement replaced. Concrete with a tiny proportion of biochar exhibited the weakest freeze–thaw resistance than control and 10% replacement. Biochar replacement promoted the formation of calcium carbonate. Biochar replacement for partial cement in concrete provides a sustainable option for municipal solid waste management and building energy consumption reduction.

Potential Assessment of Combustible Municipal Wastes in Morocco and their Ability to Produce Bio-Oil by Pyrolysis

Pyrolysis of combustible municipal solid waste (MSW) is an environmentally friendly waste to energy process that produces an ecological bio-oil with a high-energy value. However, the challenge is to obtain the desired products in considerable quantities, of good quality, and at low cost. The present work objective is to evaluate combustible MSW potential available in Morocco and their recovery in bio-oil produced by pyrolysis. An evaluation was conducted based on the MSW characterization for different Moroccan cities. It shows that Morocco has significant potential in good quality RDF, having a high calorific value and a low environmental impact. The yield of bio-oil that can be produced by pyrolysis of the dry part of municipal waste for different Moroccan cities was estimated using an appropriate model. The average total bio-oil yield estimated for each city is 45 wt%. Besides, the high calorific value fraction of bio-oil derived from Moroccan RDF will cover ~45% of the country's fuel-oil needs.

In-situ immobilization mechanism of lead and cadmium species by pyrolytic char in MSW pyrolysis process: Effect of chlorine group

The release of heavy metals brings severe environmental pollution and affects product application during the pyrolysis of municipal solid waste. Due to the excellent immobilization properties, the utilization of pyrolytic char for heavy metals is a promising approach, yet the microscopic mechanism between Cl functional groups on the char surface and Pb/Cd species remains unclear. Thus, density functional theory was applied to study the interaction mechanism between them through geometric optimization, electronic structure, and chemical reaction. Owing to the strong valence electron hybridization, the Cl functional group greatly increases the adsorption stability of Pb and Cd species. In addition, the armchair edge of char exhibits better affinity to heavy metal (belonging to the chemisorption) than that of the zigzag edge, whose fixation stability follows the order of Pb0>PbCl2>CdCl2>Cd0. Compared with the chlorination by HCl, the Cl group raises the chlorination barrier of Pb0 and Cd0 over the zigzag edge, while there is no apparent tendency over the armchair edge, since it increases the energy barrier of Cd0 but lowers that of Pb0. Therefore, the Cl functional groups of char promote the fixation of Pb/Cd and inhibit the generation of the easily leachable CdCl2, thereby facilitating the in-situ immobilization of heavy metals.

Study on the conversion of CaCl2 with H2O and CO2 for dechlorinating pyrolysis of municipal solid waste

In a pyrolysis-combustion combined process for treatment of municipal solid waste (MSW), the removal of HCl from the volatile before combustion, with a calcium-based absorbent has been broadly investigated, but the conversion of CaCl2 as the reverse reaction of the absorption of HCl has seldom been reported. In this work, the conversion of CaCl2 with H2O and CO2 (main products from pyrolysis of MSW) in the temperature range of 350 °C-650 °C is studied by fixed-bed experiments and thermodynamic analysis. The results show that the conversion of CaCl2 increases with the increase of temperature and with the increasing contents of CO2 and H2O. Comparatively, the impacts of CO2 and H2O are both stronger in lower temperatures, and the influence of H2O is more distinct than that of CO2. The existence of H2O is a prerequisite for the conversion of CaCl2, and the component of CO2 is promotive to the reaction of CaCl2.

Experiment and mechanism study on enrichment of heavy metals during MSW pyrolysis by modified kaolin.

Experiment and mechanism studies on the enrichment of Pb, Cd, Zn, As, and Cr by modified kaolin were investigated during MSW (municipal solid waste) pyrolysis at 450 ~ 650°C. The results showed that γAlOK(micro- and nano-γAl2O3 by hydrothermal method modified kaolin) was relatively selective for the solid phase enrichment of Cr and As, while CaHPK (CaHPO4 impregnated modified kaolinite) was more advantageous for the adsorption of Pb and Zn, which might be related to the thermal stability of γAl2O3 and the thermal conversion of CaHPO4. Compared with the original kaolin, the adsorption and retention capacity of γAlOK for As was improved by 20 ~ 30%. Moreover, the retention rate of modified kaolin for Cd decreased from 66.75 to 30.30% at 450 ~ 650 ℃, and the effect of temperature on the volatilization of Cd was always greater than the active components on the surface of modified kaolin. In the fluidized bed experiment, the physical mixing of different modified kaolin achieves complementary advantages on the retention capacity of heavy metals. In addition, the ∆E between Ca2P2O7 and PbCl2 is smaller than that of γAl2O3 at 500 ~ 650°C, i.e., their electron transfer induction is stronger, and therefore more favorable for electron transfer and stable chemical bond formation.

Response surface modelling of biomass-rich municipal solid waste pyrolysis: towards optimum hydrogen production

In this study, two-step pyrolysis of biomass-rich municipal solid waste was studied on nickel supported ZSM-5 catalyst. In the first stage of the reactor, constant temperature (T = 550 °C) was applied, and in the second stage, the reactions took place at 500, 700 and 850 °C. Effects of operating parameters (temperature = 500, 700, 850 °C, steam rate = 1, 5 g/h) and catalyst load (0.5, 1.0, 2.0) were studied on yields and compositions, particularly on the hydrogen contents. In order to determine the significance of the operating parameters, response surface methodology was used. Considering the experimental data, the values of hydrogen/carbon monoxide molar ratio, lower heating value and the simulation, it was found that the favourable operating parameters of two-step pyrolysis of biomass-rich municipal solid waste were 850 °C temperature and 1 g/h steam rate (gas yield: 27.1%, hydrogen yield: 9.96 mmol g−1 waste, hydrogen/carbon monoxide molar ratio: 1.8). From the data of response surface methodology, it was also concluded that temperature has a more critical effect on gas yields and composition than steam rate. However, in some cases, the synergistic effect of the two factors can also be significant.Graphical abstract

A comparative techno-economic assessment of fast pyrolysis, hydrothermal liquefaction, and intermediate pyrolysis of municipal solid waste for liquid transportation fuels production

The conversion of municipal solid waste (MSW) to transportation fuels can be an attractive route to reduce greenhouse gas emissions from the transportation and municipal sectors. Thermochemical conversion routes like hydrothermal liquefaction (HTL), fast pyrolysis (FP), and intermediate pyrolysis (IP) have been shown to be adept at converting organic dominant MSW into bio-crude or bio-oil. However, to produce compatible transportation grade fuels, it is necessary to upgrade the intermediate product (bio-crude or bio-oil) from all the processes, the extent of which differs depending on the process. Moreover, depending on the conversion technique, the production configuration can be either centralized or decentralized. In a centralized system, feed is transported to a facility to produce the intermediate and upgrade it (on-site upgrading), while in a decentralized system, the intermediate is produced elsewhere and transported to an upgrading facility (off-site upgrading).. Four scenarios were developed and modeled to compare the cost of production of gasoline, diesel and jet fuel from bio-crudes produced from HTL, FP, and IP.. The scenarios are: 1) a centralized HTL plant (C-HTL); 2000 dry t per day; on-site upgrading, 2) a centralized FP plant (C-FP); 2000 dry t per day; on-site upgrading, 3) a decentralized FP plant (D-FP); 50 dry t per day; off-site upgrading, and 4) a decentralized IP plant; 12 dry t per day; off-site upgrading.. Jet fuel was the primary fuel for comparison and the production costs were calculated to be $ 0.72, $ 0.85, $ 1.04, and $ 0.81 per liter for the C-HTL, the C-FP, the D-FP, and the D-IP plants, respectively. Secondary products (gasoline and diesel) can be produced alongside in cost ranges of $ 0.97 - $ 1.40 per liter and $ 1.02 - $ 1.47 per liter, respectively. The information conveyed in this study helps to identify the potential of thermochemical conversion processes to produce transportation fuels at competitive prices. The critical barriers to adopt such large-scale production processes and the opportunities of small-scale decentralized production are also mentioned. The outcomes of this study can be used to direct research and investment to address the major roadblocks that are slowing the extensive development of these technologies.

Producing eco-methane with raw syngas containing miscellaneous gases and tar by using a municipal solid waste char-based catalyst

Municipal solid waste pyrolysis char (MSWC) can be used as a catalyst carrier to support the synthesis of eco-methane from the syngas. In this paper, to understand the impacts of impurities in the raw syngas, the impacts of the H2/COx ratio, the H2O concentration, and the toluene concentration on methanation were investigated over a MSWC-supported Ni-based catalyst (Ni-MSWC). The varying H2/COx ratio in syngas affected CH4 and H2 concentrations in the final product. A lower H2/COx ratio corresponded to a higher CH4 concentration and a lower H2 concentration. The H2O concentration of less than 12% (vol.) in the syngas did not inhibit methanation, whereas excessive H2O was not favorable to the COx conversion; meanwhile, it destroyed the catalyst matrix by gasification. The Ni-MSWC catalyst showed a good tolerance to toluene (<100 g/Nm3), a representative of the tar. However, an excessively high concentration of toluene such as 200 g/Nm3 caused serious carbon deposition, significantly reducing CH4 yield. The introduction of H2O in 18% (vol.) in the syngas containing toluene (200 g/Nm3) alleviated carbon deposition by steam reforming of toluene; however, methanation was still inhibited. The results of this study provide guidance for the synthesis of eco-methane from the waste-derived syngas.

Multi-products oriented co-pyrolysis of papers, plastics, and textiles in MSW and the synergistic effects

Plastics, papers, and textiles are the main dry waste components of municipal solid waste (MSW). Product-oriented pyrolysis of these wastes under proper blend ratio could be important not only for improving the quality of char, oil, or gas from MSW pyrolysis, but also for enhancing the recycle of plastics from MSW. In this study, the pyrolysis characteristics of papers (ivory board, coated duplex board with grey back, kraft paper and offset printing paper), plastics (polypropylene and polyethylene), and textiles (cotton and polyester) were studied using thermogravimetric-Fourier transform infrared (TG-FTIR) analysis, gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) to obtain the optimum blend ratios for the desired products (gas, oil, volatile and char). The synergistic effects amongst different components during pyrolysis were investigated. Results showed that the co-pyrolysis of papers, plastics, and textiles under equal blend ratio promoted the production of aromatics, alkenes, water, alcohol, and phenol in volatile, but inhibited the production of CO2, CO, alkanes, and carbonyls. The optimum mass blend ratios were found to be paper: plastic: textile = 25 wt%: 50 wt%: 25 wt% and 12 wt%: 50 wt%: 38 wt%, respectively for obtaining the highest energy share in volatile and gas. While for producing char with higher surface area, higher paper ratio and lower plastics ratio is preferred. When the plastics percentage in mixture was increased from 12.5 wt% to 25 wt%, the oxygenates percentage in pyrolysis oil was reduced from 82 area% to 19 area%, further increase in plastics percentage, or, alterations of papers and textiles percentages did not show significant influence on oil composition, indicating that plastics can be recycled, without lowering the calorific values of pyrolysis oil or MSW for incineration, when their blend ratio in MSW exceeds 25 wt%.

Analysis on the absorption of hydrogen chloride with the absorbent of Na2CO3 for dechlorinating pyrolysis of municipal solid waste

ABSTRACT The amount of HCl in hot volatile from pyrolysis of municipal solid waste can be decreased with absorbent. Herein, the absorption of HCl with Na2CO3 was investigated by thermodynamic method and fixed-bed experiments. The results showed that CO2 and H2O were inhibitive to the absorption of HCl. The role of CO2 was stronger than that of H2O in lower temperatures (<730°C), while the effect of H2O became more distinct in higher temperatures. The performance of Na2CO3 was excellent in lower temperatures, while it performed worse and the performance could not be remarkably improved by increasing the dosage of Na2CO3 over 553°C. The results from experiments verified that the inhibiting effect of CO2 was stronger than that of H2O at 550°C.