DEVELOPMENT OF CONCEPTUAL TECHNICAL SOLUTIONS AND METHODS OF THEIR IMPLEMENTATION DURING THE DESIGN OF A DUST COAL STEAM GENERATOR OF SUPER-SUPER CRITICAL PARAMETERS OF STEAM 28 MPA / 600 °C/600 °C FOR 300 MW ENERGY UNIT. PART 3.

Abstract

In the third part of this article, an attempt is made to expand the range of regulation of the steam generator load from 40% to 100% by injecting recirculating flue gases taken after the water economizer into the middle radiation part of the furnace. For this, verification thermal calculations of the boiler were carried out when burning ДГ-100 coal in a wide range of variation of the recirculation coefficient Krec = 10−20% at loads of 40% and 50% of the nominal. It is shown that: a) at a load of 50%, recirculation of flue gases Krec = 13 % leads to a drop in the steam temperature along the primary path, due to which the maximum wall temperatures of all-welded screens decrease, which makes it possible to reduce the cost of boiler manufacture by reducing the use of expensive austenitic steels by 116.3 t; b) to ensure a live steam temperature of 600 °С at a load of 40%, it is necessary that Krec = 12%. This leads to a rise in the cost of the boiler in comparison with the load of 50% due to the use of steel grade 10X16N16V2MBR in the manufacture of ceiling screens. Bibl. 3, Fig. 17, Tab. 4.