TESTING OF A WATER HEATING BOILER UNIT IN THE COMBUSTION MODE OF COMPOSITE BIOFUEL PELLETS MADE ON THE BASIS OF SEWAGE SLUDGE

Abstract

The article is devoted to thermal testing of a pellet water-heating boiler unit for heating premises. Composite pellets consisting of sewage sludge (80%) and sunflower husks (20%) were used as fuel for combustion. The choice of composite fuel based on sewage sludge is explained by the fact that their disposal is an urgent problem of all sewage treatment plants in settlements. The wastewater treatment technology used at the Dnipro-Kirovograd Wastewater Treatment Plant does not provide for the disposal of sludge waste generated at sewage treatment plants, the raw materials from which were provided for research. Among a number of methods for processing sludge, one of the most promising is thermal utilization. The implementation of such a method will allow not only to meet environmental protection requirements, but also to use the energy resource of such waste. The main purpose of conducting thermal tests of the AOVA-20 water heating boiler unit in the combustion mode of a batch of composite biofuel pellet samples based on sewage sludge was to determine the boiler efficiency. The work developed a methodology for conducting thermal tests of the boiler unit. During thermal tests, the research conditions allowed using the “water heating boiler-heating system” circuit, which made it possible to determine the boiler unit efficiency based on the balance using the direct method. When using this approach to determining the efficiency, a methodology was developed for determining the useful heat Q1 consumed in the heating system and the available heat Qн released during the combustion of composite biofuel. As a result of thermal tests of the boiler unit in the combustion mode of biofuel pellet samples made on the basis of sewage sludge, the boiler unit efficiency determined by the direct balance method was 85%.