Maximum continuous rating (MCR) is the capability of steam boiler to produce and provide the stated quantity of steam continually and easily with no all kinds of deficit or unwanted effects (for example overloading, slagging or overheating) upon the principal steam boiler and its components.
It can be, actually, the minimal guaranteed evaporation within described circumstances. By using the examination of block margins obtainable throughout the different auxiliaries, it is doable to attain 8–10% extra steam coming from the steam boiler if it really is new. Certainly, with getting older, a substantive percentage of the following overcapacity could be lost, generally when components wear out and the surfaces break down. When the fuels that the steam boiler is made, tend not to degrade and the steam boiler doesn't experience any severe damages such as explosions, and the operation and maintenance routines are beneficial, a properly designed steam boiler by using good margins complies with the maximum continuous rating (MCR) possibly by the end of the designed lifetime of commonly 30 (thirty) years.
During the time of assortment and purchasing of steam boiler in case the several situations on fuel and load are obviously designed, including additional capacity to prevent a doable derating eventually is wasteful and unwanted. When the producing extra-large boiler will run at under the rated condition, the operating costs are most gonna be increased, besides the primary cost.