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Acid gas enrichment (AGE) is a new method to increase the H 2 S conversion in conventional Clause process. In this paper effect of methyl diethanolamine (MDEA) flow rate, MDEA temperature, acid gas flow rate, and AGE tower pressure on the outlet H 2 S and CO 2 concentration and energy consumption have been studied. A novel procedure based on enthalpy of combustion in the reaction furnace and incinerator is conducted for energy consumption calculations. By changing MDEA and inlet acid gas flow rates, a maximum H 2 S concentration in the enriched stream could be attainable. Increasing MDEA temperature will decrease maximum H 2 S concentration and enriched acid flow rate; also, CO 2 concentration in off-gas will be decreased. By increasing AGE pressure, maximum H 2 S concentration in the enriched stream will be diminished. At higher MDEA flow rates, lower AGE pressures will bring higher H 2 S concentration in enriched acid gas stream. According to flame temperature simulation in the reaction furnace, energy consumption is directly related to H 2 S concentration in the sulfur recovery unit (SRU) feed stream. Results show that maximum H 2 S concentration in the enriched acid gas stream has the best conditions from energy point of view. At optimum conditions, H 2 S concentration in enriched acid gas is 62.45 mol%, which has been increased by 24.8%, compared with existing plant conditions, and energy consumption has been decreased by 25.05 GJ/h, and CO 2 concentration in off-gas is 94.94 mol%. • Study the effect of process variables on the AGE streams by ProTreat software. • Determine the relation between reaction furnace temperature and H 2 S concentration. • Generate an EES procedure for heat of combustion in reaction furnace. • Evaluate the fuel gas consumption and therefore energy consumption. • Multi-objective optimization based on the TOPSIS method. [ABSTRACT FROM AUTHOR]

Altering the atmosphere type may boost the physicochemical drivers of the combustion, thus contributing to the circularity and sustainable management of hazardous wastes. This study aimed to compare the combustions of spent pot lining (SPL) in the oxy-steam and air atmospheres. The SPL combustion with 21% (Oxy21), 30% (Oxy30), and 40% (Oxy40) O 2 in the oxy-steam atmosphere improved the performance indices. Weighted mean activation energy (E m) fell from 148.36 kJ/mol in the air atmosphere to 118.04 kJ/mol in Oxy21, with the lowest E m value occurring in Oxy30 (referred to as energy-saving pathway). With the temperature rise, the pattern of fluorine distributions in the air atmosphere (the oxy-steam atmosphere) exhibited 65.60 → 92.27% (65.87 → 9.08%) of fluorine in bottom ash, 7.33 → 31.84% (22.31 → 72.83%) in off-gas, and 0.4 → 2.56% (11.82 → 22.22%) in fly ash. The increased O 2 concentration slightly affected the combustion characteristic indices and fluorine distributions. Steam appeared to enhance the pore expansion. The advance decomposition of Na 3 AlF 6 , the new emergence of NaAlO 2 , and the disappearance of CaF 2 characterized the oxy-steam combustion of SPL. The gas-ash-energy nexus was jointly optimized via artificial neural network. The oxy-steam combustion destroyed the stability of both soluble and insoluble fluorine, thus greatly releasing fluorine-bearing gas. [Display omitted] • Oxy-steam combustion was innovatively applied to the SPL treatment. • Fluorine distributions of ashes and gases were quantified. • Shift from the air to oxy-steam combustion reduced the energy barrier. • Steam boosted the outward release of both soluble and insoluble fluorides. • Ash-gas-energy nexus was jointly optimized for the first time. [ABSTRACT FROM AUTHOR]

The objective of the present study is to use life cycle assessment (LCA) to guide the design and implementation of circular business models (CBM) in the wood panel industry towards a cleaner production. Initially, searches in the literature were carried out to select articles on LCA of wood panels, to investigate the possible synergies between LCA and CBMs in the wood panel industry. Investigations of the production system of reconstituted wood panels, with regard to both the biological and technical cycles, allowed spotting signs of existing circularity in some parts of the manufacturing stage, such as the use of wastes for combustion and generation of energy, and the use of ash from combustion processes. In order to reduce impacts, identified via LCA, CBMs for the wood panel sector were proposed, seeking to reduce the impacts identified via LCA and fill the circular gaps left by existing practices. [ABSTRACT FROM AUTHOR]

This paper presents the direct combustion with energy recovery as a treatment method to wet waste (waste mixed and contaminated with organic fractions) generated from the selective collection in Brazil, based on its thermochemical characterization, searching for a final destination different from dumps, and decreasing the waste amount sent to landfills in the country. The energy recovery potential was calculated from the physical, chemical, and thermal characterization of products found in the waste stream grouped into five combustible categories (Organic matter, Sanitary waste, Paper/cardboard/Tetra Pak®, Plastics, and Textiles). The thermochemical characterization, the waste's behavior as a feedstock for energy power plants, the energy recovery potential, and GHG emissions avoided from three scenarios of electric power efficiency (18, 25, and 30%) were studied. The results show that the combustion with energy recovery could be used as a treatment method because of the Brazilian MSW characteristics as a solid fuel, such as a lower heating value of 7.22±1.76 MJ.kg−1, moisture content of 49.19±10.05%, and an ash content of 14.23±6.71%; highlighting that in some regions of the country, there is the possibility of using auxiliary fuels for waste combustion. In this way, MSW combustion facilities could contribute an additional 3% of electrical energy to the national energy matrix from the use of at least 67% of the MSW collected. Furthermore, annual emissions of about 1 million tonnes of CH 4 (24 million tonnes of CO 2 -eq) and around 140 million cubic meters of dumps could be avoided, dependent on the gross electrical efficiency used in Waste-to-Energy technology. • Direct combustion with energy recovery is proposed as MSW treatment method in Brazil. • The energy recovery potential and avoided GHG emissions were estimated. • Thermochemical characterization of wet MSW for energy recovery was performed. • The behavior of wet waste as a feedstock for energy power plants was studied. • Energy recovery from wet waste could add 3% to the Brazilian electricity matrix. [ABSTRACT FROM AUTHOR]

The combustion process of meat and bone meal (hereinafter referred to as MBM) must comply with a series of conditions and restrictions, which stem from environmental law and engineering, energy, and constructional requirements. To this end, a multi-dimensional analysis model was developed to determine the working area that provides optimal combustion process conditions. The input parameters consisted of the waste stream, exhaust gas oxygen concentration, and heat flux recovered as saturated steam. The limiting parameters of the MBM combustion process, such as the temperature of the exhaust gas after the post-combustion chamber, the temperature of the exhaust gas before the bag filter, and the exhaust gas residence time in the post-combustion chamber, constituted the output parameters. The results of the multi-dimensional analysis were visualized in terms of the distribution of the output parameter values obtained from the input parameter function. Based on a comparison of every output parameter to its corresponding limit value, optimal working areas of the thermal waste treatment system were defined. The research reveals that it is possible to determine the MBM combustion optimal working area that complies with all of the conditions and restrictions. It is worth understanding this working area during the design and construction of thermal waste treatment systems. The multi-dimensional analysis model has been verified under industrial conditions at a real MBM combustion facility. • Proper waste combustion must simultaneously satisfy various contradictory conditions. • A theoretical combustion model was developed to analyse the process. • All conditions, including environmental, performance and technical requirements, are met. • The combustion process of this type of meal requires cooling the flue gas by the air flux. • The combustion efficiency and energy recovery level must be coordinated to control the process. [ABSTRACT FROM AUTHOR]