Design and Performance Aspects of Steam Generators

Abstract

Packaged steam generators are widely used in process and power plants. They are also used as standby boilers in cogeneration/combined cycle plants. The general feeling among consultants, plant engineers and end users is that packaged steam generators are "standard" or "off-the-shelf items", that there exists a model number for a given steam capacity and one has to live with whatever performance is offered by the boiler vendor. Unfortunately, boiler suppliers also encourage specifying of steam generators based on standard, pre-packaged designs. A "standard" boiler has several limitations such as pre-determined furnace dimensions, tube length, surface area, tube spacings etc, which may or may not be the optimum choice for a given steam demand, particularly when today's emission levels have to be met. Also, operating costs, which form a significant portion of overall costs, are ignored by consultants when evaluating various designs for possible purchase. This paper highlights the importance of custom designing packaged steam generators and the resulting benefits from boiler performance viewpoint.