Thermal power plants employ regenerative type air pre-heaters (APH) for recovering heat from the boiler flue gases. APH fouling occurs due to deposition of ash particles and products formed by reactions between leaked ammonia from the upstream selective catalytic reduction (SCR) unit and sulphur oxides (SOx) present in the flue gases. Fouling is strongly influenced by concentrations of ammonia and sulphur oxide as well as the flue gas temperature within APH. It increases the differential pressure across APH over time, ultimately leading to forced outages. Owing to lack of sensors within APH and the complex thermo-chemical phenomena, fouling is quite unpredictable. We present a deep learning based model for forecasting the gas differential pressure across the APH using the Long Short Term Memory (LSTM) networks. The model is trained and tested with data generated by a plant model, validated against an industrial scale APH. The model forecasts the gas differential pressure across APH within an accuracy band of 5–10% up to 3 months in advance, as a function of operating conditions. We also propose a digital twin of APH that can provide real-time insights into progression of fouling and preempt the forced outages.

Agricultural products, such as, vegetables are generally perishable and are difficult to store. Drying is one method to reduce the increase their shelf life. Dehydrators use different type of energy as per availability and requirement. Solar dehydrators are more popular since they use renewable solar energy. In this paper such a domestic passive solar dehydrator is designed and analysed for its utility and effectiveness. The dehydrator is designed for converting the perishable agricultural products into powders so that it can be stored and used for longer time. It is designed in two parts. The first part work as a solar energy collector and the second part works as the dehydrator. The heat from solar radiations is imparted to the air in the solar collector. This hot air is used in dehydrator foe drying agricultural products. The experimentation has been performed for different temperatures and flow velocity of air varying for different vegetables depending on their moisture content and time required to remove the moisture. It is observed that drying at different temperature is required for different vegetables to convert them into powder. The taste and colour of the powder produced are found to be good. Therefore, it is suitable and affordable even for farmers with lesser quantity of products.