CYCLIC PROJECT

Basis:

Even if today's combined-cycle thermal power plants are fitted with the latest technology to cope with cyclic operation, in practical terms they have been designed to work at a base load (full load), as indicated by EPC contracts (Engineering, Procurement and Construction).

However, the behavior of the gas and electricity markets combined with the operating versatility and flexibility of these installations could, in theory, make the above-mentioned design obsolete.

Thus, power stations are subject to stops, starts and load variations at a much greater frequency than initially planned, resulting in a variable operation that exceeds the considerations of component manufacturers. How can we deal with the unexpected results of these technical decisions?

Some years ago, well-known and renowned professionals from Unión FENOSA with considerable experience in the power industry approached Applus+ with their concerns about a new power generation design based on improved energy efficiency and respect for the environment: Combined cycle thermal power stations. .... .... "In an electricity and gas market closely linked to supply and demand, where versatile and flexible Power generation is required, how will these new power plants react to cyclic operation?" ____CUSTOMER VOICE

This uncertainty regarding flexibility and consistency to face change, became the basis for the development of a new project.

The Applus+ solution for this new challenge

Our customer, recognizing our capacity and considerable experience in the field of inspection and technical assistance, asked us to take on this challenge, which resulted in an ambitious and innovative project: Identification of the technical and economic impact of cyclic operation in a combined cycle thermal power station.

This study continues to examine several clearly identified objectives concerning the unexpected effects of cyclic operation:

• To identify the key components relating to cyclic operation
• To evaluate the useful life consumed by this cyclic operation and to analyze its effects
• To determine the extra economic costs associated with cyclic operation

This work includes several clearly differentiated aspects, which are carried out in several phases:

• 1.- Selection of the critical components for cyclic operation
• 2.- Selection of case study events
• 3.- Technical impact assessment
• 4.- Economic impact assessment

Two years of work by a multidisciplinary team consisting of mechanical engineers, power plant chemists, electrical engineers, metal experts and computer programmers was required to analyze and process over 3 million operating parameters, to study equipment manuals/plans and flow diagrams, operation manuals, as well as applicable standards and norms and an international bibliography.

Advantages for our customer

This study was used to develop a method for calculating the useful life used up by the various fault mechanisms, in turn used to assess the actual wear of boilers.

Thus, based on a knowledge of the risks inherent in the identified wear mechanisms, the condition of inspection and maintenance plans was assessed and, with a view to continuous improvement, a selection of recommendations were proposed as part of an action plan including inspection, operation and maintenance modifications.

All of this will facilitate the work of technicians and supervisors at power plants belonging to Unión FENOSA (today GAS NATURAL FENOSA) enabling them:

• To increase the reliability and availability of the installations
• To reduce corrective maintenance costs
• To maintain the integrity of the power plant, personnel and the environment.

Thanks to the development of our cyclic operation cost model, current costs can be assessed and future operations can be optimized, thus facilitating decision-making concerning power generation for energy companies.

CONTACT

FERNANDO MIGUÉNS MARTÍNEZ
Plant Chemical Engineer

APPLUS+ NORCONTROL
Ctra. N-VI km.582
15168 Espiritu Santo - SADA
A Coruña - ESPAÑA
fmiguens@appluscorp.com

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