Research of processes of thermochemical disposal of components of the morphological composition and model analogs of MSW

Abstract

The article emphasizes that processing and disposal of household waste mainly concerns large densely populated cities, where millions of cubic meters of solid household waste (MSW) are accumulated annually. It was noted that thermal methods of solid waste disposal are among the most advanced methods of their processing. The advantage of these methods is a significant reduction in the volume of processed material. When waste is burned, its weight is reduced by 85-90%. In addition to reducing the volume and mass of waste, incineration of household waste allows you to obtain additional energy resources. Indicators of the amount of heat of combustion of MSW are similar to indicators of brown coal - from 1000 to 3000 kcal/kg. To date, existing waste incineration plants have a number of disadvantages, the main of which is low efficiency. The rate of useful use of thermal energy does not exceed 65%, even with the use of a more advanced property. The combustion processes themselves, the formation and composition of ash residues are affected by a large number of factors, starting with the properties and characteristics of the fuel, the physical and chemical properties of the raw materials, the parameters of the combustion process, the dispersed size of the fuel, the type of reactor, and the level of oxygen in the working area. Thus, the selection of the range of temperatures and pressures, the rate of heating of the gas medium for the thermogravimetric method of disposal of carbon-containing waste plays a decisive role in overcoming the shortcomings of this method. The purpose of the article is the development of a thermogravitational installation for studying the peculiarities of the flow of kinetic processes during the combustion of MSW samples. The article presents the development of an experimental thermogravitational unit for researching processes of thermochemical processing of carbon-containing alternative fuels with wide possibilities, which allows to study the influence of technological parameters on the combustion process. A description of the main nodes and the measurement system, the methodology of the experiment and the analysis of the obtained data is given. A series of experiments was conducted with all the main components of solid waste: wood, food waste (potatoes, meat), office and chart paper, leather, garden waste, tetrapak, plastic. It is shown that the nature of the mass change curves of various components practically does not depend on their chemical composition and is determined mainly by the staged course of the combustion process, and the latter, in turn, by the rate of heating of the sample, the only exception being the combustion of plastic. The oxidation time of all components, except plastic, after reaching the temperature of the beginning of combustion (~ 200-250, sometimes 300 °С) is from 5-7 to 40-50 minutes, while the intensive combustion of plastic ends in 1 minute. It was determined that the composition and thermophysical properties of ash play an important role in the processes of thermochemical disposal of MSW, affecting the value of the specific calorific value of MSW as a fuel and the value of the adiabatic temperature of the gaseous products of the process.