By Edward Wolfe
Managing the interfaces between water treatment steps is critical to assuring a reliable steam supply. The old saying “You are as strong as your weakest link” applies to the chain of water treatment steps that are needed to generate a reliable steam supply. The risks associated with taking inappropriate water treatment steps are present from feasibility studies, through the development of the project, on through startup, and then to current day-to-day operations. For system integration, it is important to know the real and reliable technical parameters regarding the design and performance of each treatment step, and their operating flexibility, to determine if the treatment performance required for the reliability of the plant‘s steam supply is available under controlled conditions. To eliminate problems resulting from available technology falling through the cracks, the plant owner must avoid potential pitfalls by having a thorough understanding of all water treatment steps that may be used to generate steam for the system, and the appropriate technology to be applied at each step.
There are challenges in operating these systems, and appropriate strategies must be developed and used to lessen the risk of problems resulting from the water treatment component interfaces. One of the most challenging tasks is to manage the interface between boilers and the turbines with respect to the integration of boiler water quality and steam purity.
Step-by-step procedures are required, starting with the water treatment needs to achieve the steam purity required and then working backwards to the boiler water, boiler feedwater (deaerator), condensate, makeup water, and raw water. Lowering of risk starts at the conceptual design phase and continues through contract execution, commissioning, and on-going day-to-day operations. It is essential for the plant owner to know the function of each water treatment step during all phases of the steam generating system's life in order to provide a continuous quality steam supply to the plant.
Each steam generating facility has different water quality requirements and different equipment suppliers. Therefore, to maintain a reliable steam system, it is important for the plant owner to be able to evaluate the vendors’ expertise and experience.
Understanding today's state of the art in water treatment technology for each step is essential to making properly informed decisions. This is required to determine if the influent water quality for each step is being met in order for the next step to be able to meet its effluent performance specification.
It is important to focus on the components' interfaces and the challenges in operating each to their full potential to minimize risks and have smooth on-going operations. A key to this success is the plant owner’s strategy to smooth out these interfaces without incurring excessive extra costs and causing long delays in needed corrective implementations.