Intensification of heat and mass transfer and dewatering of thermolabile organic materials

Ukraine has a high level of industry, agriculture and consumption. As a result of underutilization of recovered materials and their products into the environment returns significant amount of waste that contaminate soil, water, air. Dumps occupy large areas, long ground beneath them put out of production, they pollute the environment. The main causes of waste, lack of effective processes and capacities of processing residues, spatial and chronological dissociation processes of waste and their use, lack of sufficient market. Of all the organic waste in Ukraine is one of the main places belong chicken droppings. Fresh droppings quickly oxidizes the soil, humus and inhibits microorganisms, disrupting its natural ecosystem biological community. With some preparation and processing of chicken manure is a high quality fertilizer that contains chemical elements (N, P, K), macro- and micronutrients, humic acid and other components that are essential for growth and fertility of different plants. For decontamination litter widely used thermal drying at t = 600 – 800 °C. This product is well kept dry, easily transported, but using traditional drying facilities for its handling used large amount of heat. Today continually created and offered new modern technologies for processing chicken manure. At the Institute of Engineering Thermophysics NAS of Ukraine many years conducted investigations on the creation of modern technologies and equipment for processing organic waste. Analysis of the traditional intensification methods and processes of heat and mass transfer during drying of materials was presented in the paper. The author has proved the promising nature of the method of the combined processes of drying and dispersion using a mechanical rotor to intensify the process of drying of high–moisture thermolabile materials.

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Mathematical Simulation of Forest Fuel Pyrolysis in One-Dimensional Statement Taking into Account Soot Formation

Processes ◽

10.3390/pr9091616 ◽

2021 ◽

Vol 9 (9) ◽

pp. 1616

Author(s):

Nikolay Baranovskiy ◽

Viktoriya Kirienko

Keyword(s):

Mass Transfer ◽

Heat And Mass Transfer ◽

Programming Language ◽

Forest Fire ◽

Forest Fires ◽

Soot Formation ◽

Temperature Distributions ◽

Forest Fuel ◽

Fuel Pyrolysis ◽

High Level

Pyrolysis (thermal decomposition) is considered as the most important stage of a forest fire before direct forest fuel ignition. This process is accompanied by soot particle formation. Such particles have a negative impact on public health in the vicinity of forest fires. The purpose of this article was to investigate the heat and mass transfer process occurring in a typical forest fuel element (birch leaf). The pyrolysis and soot formation processes were taken into account, and various forest fire scenarios were considered. Computational experiments were carried out using the high-level programming language Delphi. Heat and mass transfer processes were described by nonlinear non-stationary differential heat conduction equations with corresponding initial and boundary conditions. The differential equations were solved by the finite difference method. Nonlinearity was resolved using a simple iteration. The main results of the research were (1) physical and mathematical models proposed for modeling forest fuel pyrolysis, taking into account soot formation and conditions corresponding to various forest fires; (2) a computer program coded in the high-level programming language Delphi; (3) the obtained temperature distributions over leaf thickness; (4) volume fractions obtained for various components dependent on time and space coordinates. The qualitative analysis of the dependencies showed that the temperature distributions in the birch leaf structure are similar for all forest fire types and differ only in absolute value. The intensity of the soot formation process directly depends on the forest fire type. The presented results should be useful in predicting and assessing forest fire danger, including near the facilities of the Russian Railways.

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