Desenvolvimento do conceito de um dispositivo para a valoração de cinzas de fundo de caldeira através da obtenção de alcalinizante

Abstract

The use of eucalyptus biomass in the global energy matrix, especially in the production of steam in food industry boilers, is increasing. As a residue of this process, there are ashes, considered class II waste, which need to be disposed of, generating costs for the industries. The ashes are mainly composed of alkali oxides, which can be solubilized to produce a low-cost alkalizing agent. The use of ashes has been the focus of many studies, but there are no studies on the recovery of ashes through the production of alkalizing agents in the literature. Thus, the ashes from the combustion of eucalyptus wood, originating from a boiler operating within a food industry, were chemically characterized, concluding that they are mainly composed of Calcium Oxide (CaO), Potassium (K₂O), and Magnesium (MgO), responsible for the alkalinity of the ashes. pH values ranging from 11.3 to 13.7 and maximum values of total and partial alkalinity of 19,050 and 26,000 mg/CaCO3 per 100 ml of sample were found, clearly indicating the alkaline potential of the extract. The parameters of temperature, agitation, contact time, and ash mass were analyzed through experimental design to verify their influence on alkaline extraction, where it was observed that temperature had no effect on pH and alkalinity, while ash mass and time had the most significant effects on the responses. Therefore, the focus was on the ash mass and contact time conditions. With the definition of the alkaline extract, its effectiveness was tested on a dairy effluent, showing interesting results in the removal of phosphorus, COD, turbidity, and color. The present work aims to design a device that utilizes bottom boiler ashes for the production of the alkalizing agent, following the design method proposed by Pahl et al. (2005), involving four phases: Project planning, conceptual design, concept presentation, and detailed design, developing its final form. Such a device will bring economic and environmental benefits to the industrial sector, as the machine's design was conceived for on-site use of the ashes, transforming the waste resulting from combustion into an alkalizing agent that the company can use in its effluent treatment.