Estudo e desenvolvimento de software para aplicação no tratamento de água de caldeira

Abstract

The water that feeds the boiler reservoirs comes from natural sources such as wells, lakes, rivers, streams, ponds and groundwater. For a safe and efficient operation, it is extremely important to be careful with the quality of the water that feeds this equipment, as it has impurities that can generate many problems for the generation of steam, such as incrustations, corrosive processes and drags, which compromise both the quality of the process and the useful life of the equipment, in addition to increasing the consumption of fuel and chemical products for the treatment of water and the generated effluent. The selection of the appropriate technology for the treatment depends on the type of water to be treated and this choice is strongly dependent on the water source, the type of process, the process conditions and the characteristics of the equipment. Therefore, the type of appropriate treatment varies greatly and its choice and monitoring becomes an expensive task that requires a lot of time from the professionals responsible for evaluating each parameter. The objective of this study was to present the development of a software with a little disseminated technology so far that determines the appropriate technology for the treatment of raw water to be used as a replacement source and also of boiler water, in addition to monitoring the treatment and issuing reports with technical guidelines for maintenance of the treatment and stability of the process. This software was developed with Microsoft Access which is a data manager from Microsoft Corporation. The software determines the type of treatment suitable for the make-up water and for the internal water of a boiler through the working pressure range of the equipment, the physical-chemical parameters of the water and its control ranges, system metallurgy and type of contact with food. Its use helps professionals in the field to choose the treatment technology based on the characteristics of the process and the values ​​of the parameters analyzed, such as silica, total hardness, total alkalinity, hydroxide alkalinity, pH, specific conductivity, total iron, total copper, chlorides and turbidity. After the development of the software, a case study was carried out involving a thermoelectric plant in the interior of São Paulo that has an energy cogeneration system initially operating at 48 bar and which was in the transition phase to 67 bar. Analyzes of the water parameters of the system were carried out during the period of 7 months and, with the results obtained in the analyses, the software was used to choose the best treatment for the water present in the process and to monitor the system. With the help of the software, it was possible to verify that the internal treatment adopted for the water of this boiler matches the treatment suggested for boilers operating under the same conditions according to the literature. Suggestions for improvements were also made for both pre-treatment and internal treatment so that it was possible to maintain the stability of the system and generate savings for the plant.