Introduction to Nanotechnology

Disinfection technology of hospital wastes and wastewater: Suggestions for disinfection strategy during coronavirus Disease 2019 (COVID-19) pandemic in China.

Scientific studies have demonstrated that it is possible to generate a wide variety of bioenergy from biomass residues and waste, and however its cost is not competitive with petro-fuels and other renewable energy. On-going efforts are continued extensively to improve conversion technologies in order to reduce production costs. The present review focuses on the conversion technologies for transforming biomass residues and waste to biofuels, specifically their technological concepts, options and prospects for implementation are addressed. The emerging developments in the two primary conversion pathways, namely the thermochemical (i.e. gasification, liquefaction, and pyrolysis) and biochemical (i.e. anaerobic digestion, alcoholic fermentation and photobiological hydrogen production) conversion techniques, are evaluated. Additionally, transesterification, which appears to be the simplest and most economical route to produce biodiesel in large quantity, is discussed. Lastly, the strategies for direct conversion of biomass residues and waste to bioelectricity including the use of combustion and microbial fuel cells are reviewed.

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Waste to bioenergy: a review on the recent conversion technologies

This paper proposes an overview of waste-to-energy conversion by gasification processes based on thermal plasma. In the first part, basic aspects of the gasification process have been discussed: chemical reaction in gasification, main reactor configuration, chemical conversion performances, tar content in syngas and performances in function of the design and the operation conditions (temperature, pressure, oxidizing agent…). In the second part of the paper are compared the performances, available in the scientific literature, of various waste gasification processes based on thermal plasma (DC or AC plasma torches) at lab scale versus typical performances of waste autothermal gasification: LHV of the syngas, cold gas efficiency and net electrical efficiency. In the last part, a review has been done on the various torch technologies used for waste gasification by plasma at industrial scale, the major companies on this market and the perspectives of the industrial development of the waste gasification by thermal plasma. The main conclusions are that plasma technology is considered as a highly attractive route for the processing of waste-to-energy and can be easily adapted to the treatment of various wastes (municipal solid wastes, heavy oil, used car tires, medical wastes…). The high enthalpy, the residence time and high temperature in plasma can advantageously improve the conditions for gasification, which are inaccessible in other thermal processes and can allow reaching, due to low tar content in the syngas, better net electrical efficiency than autothermal processes.

/pdf/waste-gasification-by-thermal-plasma-a-review-4cx0hem5be.pdf

Waste Gasification by Thermal Plasma: A Review

In this paper, we establish a new data-based iterative optimal learning control scheme for discrete-time nonlinear systems using iterative adaptive dynamic programming (ADP) approach and apply the developed control scheme to solve a coal gasification optimal tracking control problem. According to the system data, neural networks (NNs) are used to construct the dynamics of coal gasification process, coal quality and reference control, respectively, where the mathematical model of the system is unnecessary. The approximation errors from neural network construction of the disturbance and the controls are both considered. Via system transformation, the optimal tracking control problem with approximation errors and disturbances is effectively transformed into a two-person zero-sum optimal control problem. A new iterative ADP algorithm is then developed to obtain the optimal control laws for the transformed system. Convergence property is developed to guarantee that the performance index function converges to a finite neighborhood of the optimal performance index function, and the convergence criterion is also obtained. Finally, numerical results are given to illustrate the performance of the present method.

Adaptive Dynamic Programming for Optimal Tracking Control of Unknown Nonlinear Systems With Application to Coal Gasification

Processing of biomedical waste in plasma gasifier.

Plasma technologies reduce the environmental impact and enhance the thermal efficiency of low grade solid fuel utilisation. The present study presents two mathematical models of the plasma thermochemical preparation for incineration, plasma gasification and complex processing of pulverised coal. Numerical computations of temperature, velocity and component concentrations have been compared with experimental data obtained in a 70 kW laboratory plasma installation processing 11 kg h−1 of low grade coal. Satisfactory agreement between the simulations and experiments enabled the design of a 1000 kW pilot installation capable of plasma processing 300 kg h−1 of coal.

Plasma technologies for solid fuels: experiment and theory

Plasma supported solid fuel combustion is promising technology for use in thermal power plants (TPP). The realisation of this technology comprises two main steps. The first is the execution of a numerical simulation and the second involves full-scale trials of plasma supported coal combustion through plasma-fuel systems (PFS) mounted on a TPP boiler. For both the numerical simulation and the full-scale trials, the boiler of 200 MW power of Gusinoozersk TPP (Russia) was selected. The optimization of the combustion of low-rank coals using plasma technology is described, together with the potential of this technology for the general optimization of the coal burning process. Numerical simulation and full-scale trials have enabled technological recommendations for improvement of existing conventional TPP to be made. PFS have been tested for boilers plasma start-up and flame stabilization in different countries at 27 power boilers steam productivity of 75–670 tons per hour (TPH) equipped with different type of pulverised coal burners. At PFS testing power coals of all ranks (brown, bituminous, anthracite and their mixtures) were used. Volatile content of them varied from 4 to 50%, ash—from 15 to 48% and calorific values—from 6700 to 25,100 kJ/kg. In summary, it is concluded that the developed and industrially tested PFS improve coal combustion efficiency and decrease harmful emission from pulverised coal-fired TPP.

Vladimir E. Messerle

Papers

Processing of biomedical waste in plasma gasifier.

Plasma technologies for solid fuels: experiment and theory

Plasma-aided solid fuel combustion

Hydrogen production by coal plasma gasification for fuel cell technology

Plasma assisted power coal combustion in the furnace of utility boiler: Numerical modeling and full-scale test