Comparative analysis of methods for determining the flammability of municipal solid waste as railway transport cargo

A statistical analysis of information about fires that occurred on the railroads shows that it is necessary to enhance the fire protection measures while transporting the fire-hazardous materials (FHM). A comparative analysis of the use of the exergetic index and the flammability potential for forecasting the fire risks connected to the railroad FHM transportation has been performed. The studies considered municipal solid waste (MSW) as promising railway cargo. The values of the MSW chemical exergy and the heat of combustion have been calculated. The conditions and behavior of their variations have been investigated. A system of the substances and materials classification that is based on the exergetic coefficient was introduced. The proposed approach allows us to resolve methodological problems caused by the requirement to account for the technical, economical criteria, and the fire risk indexes into a unified classification system. The conception of the exergetic index improves the objectivity of the procedure for the estimation of the MSW flammability properties.

Application of the Holt — Winters Model and the Exergetic Method for Predicting Safe Waste Management in the Russian Federation

The problem of waste management is acute in the Russian Federation. Not enough attention is paid to the systematic studies of their composition and properties. The purpose of the work is to conduct a comprehensive analysis of data on waste generated, to select models for predicting their mass, composition, and properties, to substantiate the feasibility of using exergetic analysis to assess safety and make informed decisions on the management of solid municipal waste management. To predict the volume of waste generation, the following were used: an integrated autoregression model — a moving average and exponential smoothing models. The study of changes in the composition and properties of the municipal solid waste, the choice of technology and the assessment of safety in waste management were carried out using the exergetic method. Its advantages are determined by the possibility of conducting a comprehensive energy-ecological assessment and determining the fire hazard of waste and the processes of handling them. The application of the Holt-Winters model for predicting the mass of the generated waste is substantiated. The analysis of changes in the morphological composition of waste, their distribution by types of economic activity is carried out. The values of chemical exergy of municipal solid waste are determined, and a forecast of its further growth is constructed. The dependences of chemical exergy on the heat of combustion of waste are found. It is determined that it is advisable to consider chemical exergy as a heat engineering characteristic and an indicator of fire and environmental hazard of waste. It is proved that the exergetic efficiency of the incineration process is higher than that of composting and burial. Transportation of garbage from the large cities by road and rail transport for subsequent disposal and recycling can be considered as a forced temporary measure during the development of the branch of industry and the formation of a waste management culture. For the application of the exergy method in the system for ensuring safety when handling solid municipal waste, a data mining system was developed. It is advisable to use the obtained results for the development of safety requirements for the management of production and consumption waste in the Russian Federation.

Exergy analysis of an atmospheric residue desulphurization hydrotreating process for a crude oil refinery

The exhaustion of petroleum reserves and the declining supply of conventional feedstock have forced refineries to use heavier crude oil in their production. Removing the undesirable components containing sulphur and metals in the atmospheric residue (AR) fraction requires extensive catalytic hydrotreating (HT) atmospheric residue desulphurization (ARDS) process. In this work, we endeavour to collect and present a comprehensive dataset to develop and simulate the ARDS HT model. This model is then used for an exergetic analysis to evaluate the performance of the ARDS HT model regarding the exergy destruction, the location of losses and exergetic efficiency. The massive exergy destruction is caused by significant differences in chemical exergy of source and product streams during separations, fractionation and reactions. The exergy destruction in the equipment independent of chemical exergies such as heat exchangers, pumps and compressors is relatively low. This exergetic analysis revealed that the majority of the processing equipment in the ARDS HT process performed satisfactorily. However, the remaining equipment requires improvement for its performance in regards to exergetic efficiency or/and avoidable exergetic losses. To enhance the efficiency of the equipment that is intensive in terms of exergy and energy use, the use of clean and high purity renewable hydrogen and several process rectification is proposed.

Chemical and Mechanical Aspect of Entropy-Exergy Relationship

The present research focuses the chemical aspect of entropy and exergy properties. This research represents the complement of a previous treatise already published and constitutes a set of concepts and definitions relating to the entropy–exergy relationship overarching thermal, chemical and mechanical aspects. The extended perspective here proposed aims at embracing physical and chemical disciplines, describing macroscopic or microscopic systems characterized in the domain of industrial engineering and biotechnologies. The definition of chemical exergy, based on the Carnot chemical cycle, is complementary to the definition of thermal exergy expressed by means of the Carnot thermal cycle. These properties further prove that the mechanical exergy is an additional contribution to the generalized exergy to be accounted for in any equilibrium or non-equilibrium phenomena. The objective is to evaluate all interactions between the internal system and external environment, as well as performances in energy transduction processes.

Development of a Loss Method for Energy and Exergy Audit of Condensing Hot Water Boilers

Condensing boilers are used in commercial and residential buildings extensively. In this paper, a loss method is proposed to estimate the energy and exergy efficiencies of condensing hot water boilers. The presented method is based on the development of the method presented in ASME PTC 4.1. Energy loss terms consist of exhaust flue gas, carbon monoxide formation, radiation, and condensate outflow sensible heat. Exergy loss terms also include radiation losses, physical exergy of the exhaust flue gas, chemical exergy of the exhaust flue gas, increase in the chemical exergy of the flue gas due to carbon monoxide formation, condensate outflow exergy, boiler exergy destruction, and economizer exergy destruction. Energy and exergy efficiencies are calculated by estimation of these loss terms. To depict the method 's capability and compare results with the direct method, an experimental setup was designed and constructed. Results of energy and exergy audition of the boiler by applying the loss method are compared with the direct method. The results show that, although the condensing economizer improves energy efficiency, it does not improve the exergy efficiency significantly. The energy and exergy efficiencies were calculated 98.65 and 5.14 percent, respectively.