A case study: The effects of the design factors on the thermal profile of Shahid Rajaiee boiler

One of the important issues in the design of water tube boilers is the estimation of their thermal profile. Having the thermal behavior of water walls, one can evaluate the effect of different parameters on thermal profile and also can recognize the critical points of boiler water walls. This paper presents a method for the estimation of boiler thermal profile and shows the effect of key design parameters i.e. heat flux, mass flux, diameter and pressure by using a computer program. The program is home made software and can calculate the heat transfer coefficient, fluid quality and tube wall temperature by using the correlations which are applied by boiler manufacturers. The temperature profile of Shahid Rajaiee power plant boiler which is a natural circulation conventional type has been calculated by the program in multi-zone model and it has been compared with the actual boiler profile. The maximum error for each method which is the maximum difference between the actual measured boiler temperature profile and the estimated boiler temperature profile is estimated. It has been shown that it is 2.9% and 3.74% for the IHI Co. and Babcock Co. methods, respectively. Therefore, the IHI Co. method has been chosen for the study of key parameters on the boiler thermal profile. The results show that although 4-zone model can estimate the boiler temperature distribution with good accuracy, however the 10-zone and 32-zone models give smoother temperature distributions.