Викиди забруднювальних речовин від спалювання поширених на ринку України пелет як палива для пелетного котла з пальником ретордного типу

Abstract

The presented work was carried out with the aim of assessing the energy and environmental characteristics of fuel pellets available in Ukraine, which are used as a fuel in a domestic hot water boiler SET with a capacity of 25 kW. SET boilers are designed for heat supply of residential buildings, municipal and industrial buildings, equipped with heating systems with natural or forced circulation of water as a coolant. Sketch drawings and some thermal hydraulic characteristics of these boilers are presented in the open access.Solid fuel combustion modeling was performed using finite element CFD models of the boiler unit with subsequent deter-mination of the ecological and energy characteristics of the boiler operation in the ANSYS Student software package, which is absolutely free (since 2015) and is intended for solving introductory and educational tasks in an academic environment. The results of CFD modeling were verified on a computer model of the prototype boiler «SET-25» according to the passport data presented by its developer. The verification was performed for the case of burning pellets from hardwood. It was shown that the discrepancy of the results does not exceed 2%, therefore the developed model can be used to model the burning of other common types of pellets — from coniferous wood, rapeseed, from bird droppings and straw, as well as from bottom sludge. The results of the thermal and environmental characteristics of the water heating boiler operation were obtained, which can be useful in the design of new water heating boiler designs and the verification calculation of existing ones. The level of formation of harmful substances during the combustion of different types of fuel pellets in the boiler was determined. It was established that the highest level of NOx emission is when burning pellets from bottom sludge (550 ppm), and the lowest (180 ppm) is when burning pellets from hardwood. It has been shown that when using different types of fuel pellets in a boiler, the boiler's operating parameters are met, provided that the daily fuel consumption is increased compared to the use of the base fuel — pellets made from hardwood.