Cement clinker production in Egypt till 2013 relied mainly on fossil fuel as a primary energy source. However, with multiple fossil fuel shortages, the utilization of biomass wastes was initiated by multiple cement producers. In the current work, and to present an industrial-scale biomass and coal co-combustion study, the utilization of multiple biomass fuels to substitute a portion of bituminous coal was studied in an Egyptian clinker production plant. Mixtures of biomass fuels were used to reduce the consumption of bituminous coal and to investigate the diminishing of the environmental impact of the clinker production process. The current study was conducted during 8 days of the stable clinker production process by replacing 14% of bituminous coal with biomass mixtures while monitoring the major process control parameters and resulting emissions. Emission results were compared to the nation’s regulations. A conclusion can be made that using biomass mixtures as alternative fuels minimized the dependency on coal as the main fuel and reduced the CO2 burden of the cement production process. In addition, NOx and SO2 emissions were declined while CO emissions were increased by utilizing biomass mixtures as alternative fuels; all emissions, however, were below the allowable limits stated by the Egyptian environmental authority. Noticeably, the heavy elements, dioxins, and furans were not changed significantly compared to those produced using coal only.

This paper discusses the 2000–2018 evolution of energy and metals recovery from urban wastes in the European Union and China. As a result of the zero-landfilling directive, in twenty years the European Union tripled its recycling rate (11%–30%) and its composting rate (6%–17%), doubled its WTE rate (14%–28%) and more than halved its landfilling (64%–25%). At the beginning of this century, the rapidly growing cities of China were literally surrounded by landfills. Therefore, the national government instituted policies, such as a credit of US$30 per MWh of WTE (waste to energy) electricity that resulted in the construction, by 2020, of 510 WTE plants with an annual WTE capacity of 193 million tons. In comparison, the European Union (EU) WTE capacity is 96 million tons and the USA has remained static at about 27 million tons, i.e., 10% of its post-recycling MSW (municipal solid waste), with the other 90% being landfilled. In the first decade of this century, two WTE technologies, moving grate and circulating fluid bed were developed in China at about the same rate. However, since 2010, the moving grate technology has become dominant and the WTE plants are built functionally and esthetically comparable to and U.S. plants.

Municipal solid waste (MSW) generation and characterization are the basic inputs for waste handling and treatment systems design. In present research, we performed waste characterization investigations in Visakhapatnam (India), using a waste characterization methodology by integrating two standard sampling and characterization approaches. The characterization methodology was designed by combining seasonal variations, source, and socio-economic stratifications. Source-based sampling was performed at household(s), dumpster(s), transfer station, and landfill. Socio-economic-based sampling was performed based on the zone classification of the city. Three sampling campaigns were conducted to identify the waste composition based on seasonal variations. Studies aimed to perform stratified characterization of waste and assess chemical characteristics of the mixed waste fractions to evaluate waste-to-energy potential. Results indicate that the amount of MSW generated in the city is 1250±100 tons/day, with a generation rate of 0.65 kg/capita/day. Based on source stratification, organic matter (45.5%?±?6.5%) is a major component followed by inert waste. The paper, plastic, and textile components amount to 25% of overall waste. From seasonal studies, organic matter was higher in pre-monsoon (42%) compared to winter (39%). The moisture content of MSW varied between 30% and 35% and volatile solids between 39% and 43%. The calorific value was determined to be between 5680 – 7110 kJ/kg. Outlined the limitations and potential errors associated with sampling and waste characterization. Biochemical and thermal conversion treatment alternatives for processing, treatment, and handling were discussed. The findings of this research would assist regulatory bodies and city councils to formulate policy directives on waste sampling, characterization, segregation, education, and awareness campaigns.

This research effort focuses on the co-pyrolysis of cassava peels waste and some synthetic polymers towards energy conversion and reducing the volume of these waste fractions dumped on dumpsites. The co-pyrolysis behavior and pyrolysis kinetics of various synthetic polymer wastes/cassava peel blends were investigated by blending cassava peel waste with low-density polyethylene (LDPE), polyethylene terephthalate (PET), and polystyrene (PS) at different weight ratios. The physical characteristics of each sample were investigated and the co-pyrolysis experiments were conducted at a heating rate of 10 °C/min from room temperature to 800 °C in N2 atmosphere in a thermogravimetric analyzer. Subsequent to thermal decomposition, kinetic analysis was done using the thermogravimetric data. Results from physicochemical characterization showed that cassava peel has a relatively lower calorific value of 15.92 MJ/kg compared with polystyrene (41.1 MJ/kg), low-density polyethylene (42.6 MJ/kg), and polyethylene terephthalate (21.1 MJ/kg). The thermal decomposition behavior of cassava peel was seen to be significantly different from those of the synthetic polymers. The decomposition of the biomass material such as cassava peel generally occurs in two stages while the decomposition of LDPE, PS, and PET occurred in a single stage. The activation energy required for thermal degradation in cassava peel was also found to be lower to that of the plastic material. The co-pyrolysis of cassava peel and different synthetic polymers affected the thermal and kinetic behaviors of the blends, reduce the activation energy and residue after pyrolysis.

Metal corrosion and ash deposition are two common issues in municipal solid waste incineration (MSWI) plants. An in-situ sampling investigation was conducted in an MSWI plant in Jiangsu, China. The deposit samples were collected from 6 convective heating surfaces including the reheaters, superheaters, and economizer. The corrosion samples were obtained from a ruptured tube cut from the tertiary superheater. The element composition, crystal phases, and morphology of deposit and corrosion samples were characterized and analyzed. The results show that S contents of these deposits are 32–45 wt%, considerable Cl (10.63 wt%) was only detected in the deposits of the tertiary superheater. The composition of the deposits varies with the location because the flue gas temperature determines the thermodynamic trend of the sulfation reactions of different chlorides and the SO2 equilibrium partial pressure required in these reactions. Ca sulfates mainly exist in deposits at high temperatures (above approximately 500 °C). Whereas alkali metal sulfates are the main component of deposits at low temperatures (below approximately 500 °C). A multi-layer structure is exhibited on the cross-section of the corrosion samples. The discovery of Cl in the interface between the matrix and the oxide layer confirms that Cl can penetrate the outer oxide film. Besides, polysulfate components were observed inside the metal oxide layers, which indicates that a melt has occurred there. This study has provided a better understanding of ash deposition and corrosion phenomena in MSWI systems and more emphasis should be placed on the research of ash deposition and corrosion mechanisms.

To make coal-fired power generation more environmentally friendly, China has initiated a series of ultra-low emission retrofits to the air pollution control (APC) system of the existing power plants. In this study, a life cycle assessment (LCA) is conducted to analyze the environmental net benefits for the typical ultra-low emission retrofit of a 1000 MW power plant. The key processes, substances, and APC devices are verified and discussed. The results confirm that the retrofit effectively decreases the environmental stress of acidification potential (AP), eutrophication potential (EP), and photochemical ozone creation potential (POCP) by 69%–79%, which can be attributed to significantly reduced emissions at the stack. However, the retrofit has also increased other impact categories by 24%–79%, primarily due to the consumption of additional electricity and adsorbents. The retrofit of selective catalytic reduction, electrostatic precipitator (ESP), and wet limestone flue gas desulfurization devices has a dominant effect on the impacts of EP, human toxicity potential (HTP), and AP. A newly installed wet ESP shows some environmental benefits (only for AP), but causes considerable burdens, in particular for the investigated impact categories global warming potential (GWP), marine aquatic ecotoxicity (MAETP), and abiotic depletion fossil (ADP fossil). The obtained results indicate that the hidden environmental consequences, which are associated with the production of energy and materials, need to be examined more comprehensively to inform the development of ultra-low emission technologies and strategies effectively.

The increase of CO2 concentration in the atmosphere has brought serious greenhouse effects and environmental problems, so it is urgent to solve the problem of excessive CO2 concentration. The carbon capture, utilization, and storage technology refer to the use of CO2 as a C1 resource to generate new economic benefits in a new production process. In this work, the influence of adding different proportions of N2 and Ar to the CO2 gas on the discharge characteristics and reaction performance was investigated with a newly designed dielectric barrier discharge (DBD) micro-plasma segmented electrode reactor and optical emission spectroscopy. The results indicated that the discharge current value increased when the added N2 content was less than 50%, and decreased when the N2 content exceeded 50% under the condition of constant input power. The number and the current value of mixed gas micro-discharges showed a decreasing trend with the increase of Ar content. In the discharge system, the dielectric capacitance (Cd) and the gas gap capacitance (Cg) showed opposite trends with the increase of N2 and Ar content. The dielectric capacitance decreased and the gas gap capacitance increased as the N2 content increased, while the trend was just the opposite as the Ar content increased. In addition, adding a small amount of N2 and Ar was conducive to the conversion of CO2, but when the N2 and Ar content exceeded 50%, the amount of CO2 converted will be reduced.

The fluid flow in a selective catalytic reduction (SCR) system of a 600 MW power station is optimized using the numerical simulation method in this work. Given that guide plates and straightening gratings are properly installed, the relative standard deviation (Cv) of velocity related to the inlet of an ammonia injection grid (AIG) and catalysts satisfy the engineering demand of?<15%, suggesting that a relatively uniform velocity field is obtained. The in-line arrangement of static mixers strengthens the disturbance of fluid, promoting the mixing of reductant NH3 with flue gas. The NH3 mole fraction Cv value correlated to the inlet of catalysts drops to ca. 3.5%, which is lower than that in the cases when the mixers are aligned in a staggered style. These results indicate that a solid foundation is achieved for the effective abatement of NOx in practical applications.