The object of the modeling is the process of burning organic waste, depending on the nature of the origin of the fuel, its chemical and fractional composition, density and lower calorific value. Processing the results of experimental study using analysis of variance will allow to estimate the variance caused by each factor individually and determine the level of influence of the factors on the output parameters of the process. It is necessary to obtain not only the form of this dependence, relying on the experimental data, but also to assess the influence of each factor on the lower calorific value. The analysis of the obtained dependence shows that the airflow speed and the fractional composition of this fuel have the greatest influence on the efficiency of the boiler plant. Checking the significance of the coefficients showed that all the coefficients of this model are significant. The regression dependencies were obtained that estimate the lower calorific value and the efficiency of the boiler which burns briquettes from organic matter; the analysis of the obtained dependencies was carried out, the significance of the coefficients included in the model was checked; the composition factor has the greatest influence on the lower calorific value.
One of the options for reducing harmful emissions in the production of heat energy is the use of biomass, including in combination with industrial waste (for instance, coal and coke dust). Recent studies demonstrate that a mix of biomass and coal makes it possible to obtain a bio-coal briquette with better characteristics, which is a motivating factor in the search for alternative sources of heat energy from local agricultural waste. The aim of this research is to study the properties of bio-coal briquettes from biomass (sunflower husks and leaves) and industrial waste (coal and coke dust). The raw material was grinded and used for the production of bio-coal briquettes of 20%, 30%, 40%, 50%, 60%, and 70% of biomass. The biomass was grinded to the size of no more than 2 mm for the fine fraction and no more than 6 mm for the coarse fraction. The briquettes were made mechanically using a hydraulic press with a compression pressure of 25 MPa without the use of any binder. The characteristics of the investigated bio-coal briquettes, such as density, strength, moisture content, ash content, volatile yield, calorific value, ignition time, burning duration, and burning rate, have good enough values. The fine fraction briquettes compared to the coarse fraction briquettes have a longer burning time (about threefold longer) and a lower burning rate. For all briquettes, an increase in the composition of coal dust results in a rise in the burning time, whereas the burning rate falls. The best in terms of strength, calorific value and combustion parameters are the following briquettes: 70% sunflower husk and 30% coal dust from the Karazhyra deposit; 60% sunflower husk and 40% coal dust from the Shubarkul deposit; briquettes from 70% sunflower husk and 30% coke dust; briquettes from 80% leaves and 20% coal dust from the Karazhyra deposit; and briquettes from 70% leaves and 30% coal dust from the Shubarkul deposit. The selected briquettes are suitable as an alternative source of fuel.
A setup for determining the ultimate strength of refractory materials in compression at high temperatures is examined. The value of the ultimate strength of periclase-carbon materials in compression in the temperature range 20 -500°C are presented. The fracture process and strength are analyzed.High-temperature plants are lined with refractory materials. In addition, the service life of many high-temperature plants is determined by the service life of the lining.Optimization of the factors influencing the stability of the lining makes it possible to increase the working run of a plant several-fold. Even without changing the form of the refractory a significant result can be achieved by simply improving the operating conditions (temperature regimes).Physical factors such as expansion and cracking arise in the case of thermal action on furnace lining. It becomes necessary to operate the plant continually without damaging the integrity of the lining in the working chamber and the technical-economic indices of the process.To prevent the lining from being damaged by the stresses arising during heating it must be operated in a regime where stresses grow at a rate below their relaxation rate. It is important to calculate the values of the thermal stresses when calculating the rate of heating. The stress values calculated using computational relations are compared with the admissible values, and on this basis a conclusion is drawn concerning the rate of heating of the plant. The average heating rate of high-temperature plants is about 60 K/min [1].The ultimate strength of the material is used in the calculations as the admissible value of the stresses arising with a change in the temperature field. Knowing the exact temperature dependence of the ultimate strength of the materials used it is possible to determine the maximum rate of heating of a plant (according to the conditions under which stresses arise).The results of tests performed on carbon-containing refractories produced by 'Kombinat Magnezit' JSC are presented in [2]. The characteristics and the stability of the parts are indicated and it is noted that the refractories have a high resistance to thermal shearing in the presence of temperature fluctuations. It should be noted that the ultimate strength in compression (ranging from 19 to 61 MPa for different types of refractories) is presented only at temperature 20°C. Thus, the plant data do not show the dynamics of the change in this parameter as a function of temperature.In the development of heating regimes for high-temperature plants the values of many parameters are constants, i.e., they are independent of temperature. For example, for calculations the specific heat capacity c, thermal conductivity l and ultimate strength s are often taken as constants. At the same time the value of the ultimate strength of a material in compression depends strongly on the temperature.The temperature dependence of the ultimate strength of ceramic material used as lining is of great importance for the development of heating sc...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.