In this paper, the characteristics of physical and chemical composition of municipal solid waste (MSW) in China were reviewed and the statistical indexes, namely mean value, standard deviation, coefficient of variation, and t-test, were applied to analyze the physical composition, proximate, ultimate analysis, and heating value. Listed in decreasing sequence, the physical components of Chinese MSW are in food residue, non-combustibles, plastics, paper, textiles, wood waste, and rubber. In food residue, the average elementary hydrogen (H), oxygen (O) and nitrogen (N) content varied greatly with samples and the chlorine (Cl) and moisture contents were extraordinarily high. While conversely, the components of wood waste were simple and different components displayed little disparity in characteristics. The elemental compositions of paper and textiles were also simple. The properties of chlorine-free plastics (polyethylene, polypropylene and polystyrene) were consistent, with high volatile matter, carbon (C) and H content. The mean higher heating value (HHV) of polrvinyl chloride (PVC) was about a half of that of chlorine-free plastics, because the Cl content of PVC was approximate 50%. It suggested that plastics with or without chlorine should be separated as possible. The HHV of different rubbers varied sharply, from 21,812 to 38,868 kJ/kg. A model was proposed to predict the proximate and ultimate analysis and heating value from physical composition, in which the PVC fraction in plastics and the supplementary moisture coefficient were introduced. The results showed that the predicted results fitted well with the measured ones.

An overview of characteristics of municipal solid waste fuel in China: Physical, chemical composition and heating value

Forced convection heat transfer in a semi annulus under the influence of a variable magnetic field

https://docs.lib.purdue.edu/cgi/viewcontent.cgi?article=2875&context=iracc

High temperature heat pumps: Market overview, state of the art, research status, refrigerants, and application potentials

Abstract This study reviews the current state of the art and the current research activities of high temperature heat pumps (HTHPs) with heat sink temperatures in the range of 90 to 160 °C. The focus is on the analysis of the heat pump cycles and the suitable refrigerants. More than 20 HTHPs from 13 manufacturers have been identified on the market that are able to provide heat sink temperatures of at least 90 °C. Large application potentials have been recognized particularly in the food, paper, metal and chemical industries. The heating capacities range from about 20 kW to 20 MW. Most cycles are single-stage and differ primarily in the refrigerant (e.g. R245fa, R717, R744, R134a or R1234ze(E)) and compressor type used. The COPs range from 2.4 to 5.8 at a temperature lift of 95 to 40 K. Several research projects push the limits of the achievable COPs and heat sink temperatures to higher levels. COPs of about 5.7 to 6.5 (at 30 K lift) and 2.2 and 2.8 (70 K) are achieved at a sink temperature of 120 °C. The refrigerants investigated are mainly R1336mzz(Z), R718, R245fa, R1234ze(Z), R600, and R601. R1336mzz(Z) enables to achieve exceptionally high heat sink temperatures of up to 160 °C.

High Temperature Heat Pumps: Market Overview, Stateof the Art, Research Status, Refrigerants, and Application Potentials

Biomass is currently seen as a promising renewable energy source, which can be sustainably utilized in the production of fuels and electric energy adding no carbon dioxide to the environment. Co-gasification has unveiled its potential amongst thermal techniques, as a result of the valuable products obtained, strengthening a solid position in the conversion of residues. Thus, the prevention of a complete depletion of non-renewable sources is supported and the effects of their utilization alleviated. Extensive literature review was conducted and, few reports on co-gasification of biomass and wastes were found. In this context, this review addresses their thermal conversion, highlighting issues related to the equipment, operating conditions and physicochemical phenomena involved in such a complex process. Among other conclusions, the most important finding of this work was the synergy often encountered between the two feedstocks, proving co-gasification can overcome several of the individual gasification issues enhancing products quality and yields over biomass or wastes alone, and attesting its environmental-friendly character, with lower greenhouse gas emissions. It was also possible to depict some trends on the effect of biomass and waste blending ratios, as well as elucidating some of the mechanisms involved in their interaction. These are majorly explained by the response of molecules during pyrolysis and by hydrogen transfer from waste polymers to biomass derivatives. Experimental conditions were also assessed, fluidized beds being reported as the most suitable reactors for biomass and wastes, under several different possible combinations of operational parameters. A critical discussion is presented, aiming to contribute to a more profound understanding of this matter, its key points and noteworthy potential.

Na Deng

Papers

Analysis of typical public building energy consumption in northern China

Experimental study on heat pipe assisted heat exchanger used for industrial waste heat recovery

Energy, exergy, economic, and environmental analysis of an integrated system of high-temperature heat pump and gas separation unit

Experimental analysis on performance of high temperature heat pump and desiccant wheel system

Investigation of Support Vector Machine and Back Propagation Artificial Neural Network for performance prediction of the organic Rankine cycle system