This paper presents a method for determining the temperature distribution in the cross-section of waterwall tubes connected by fins using an in-house numerical algorithm prepared in the MATLAB environment, based on differential equations with separable variables. In order to verify the correctness of the algorithm operation, the temperature values obtained from it, determined for the frontal area of the tubes, are compared with the temperatures found in the Ansys Fluent environment and those measured on the test stand. A system corresponding to a fragment of the combustion chamber wall of a supercritical steam boiler was selected to perform the analysis. The system consists of three tubes connected by fins. The temperature distributions in the cross-sections of the tubes were compared for the case when each of the tubes was heated on one side with the same heat flux and when the heat flux falling on the central tube was by 50% higher than the heat flux incident on the neighbouring tubes. Experimental verification was carried out on a stand equipped with three vertical tubes connected by fins, heated on one side by infrared radiators.

This paper presents a test stand for the capture of CO₂ from flue gases arising due to firing pulverised hard coal. The stand, financed from the 2014–2021 Norway Grants, is installed at a Polish power plant. The innovation of the proposed CO₂ capture method, developed by the Norwegian partner in the project (SINTEF Industry), lies in the use of activated carbon in the process of temperature swing adsorption in a moving bed. The paper also presents preliminary results of numerical simulations performed using the General PROcess Modelling System (gPROMS) software. The simulations concerned the operation of a supercritical power unit combined with a system for capturing CO₂ from flue gases. Transient operation of the system was analysed, assuming rapid changes in the power unit load. Special attention was paid to the CO₂ capture process energy consumption at an increase in load by 5% of the power unit nominal capacity in 30 s. It is found that the proposed CO₂ capture method “keeps up” with such rapid load changes at the method energy consumption smaller than 2 MJ/kg CO₂.