The Francisco Perez Rios power plant has undergone a full-scale modernisation at Tula in Hidalgo state, near Mexico City. The Mexican utility Comisión Federal de Electricidad (CFE) awarded Siemens Power Generation and MHI the modernisation contracts, valued at almost $200m. These have increased the power output to 1,546MWe and will extend the power station’s life by more than 20 years.
The plant consists of five 300MW oil-fired units. Modernisation of Units 3 and 4 was completed by Siemens in 2007, and modernisation of Unit 5 by MHI is underway. The work is part of
the CFE’s strategy to improve the long-term performance of its steam power plants.
MODERNISING AND UPGRADING
The Siemens contract was for Units 3 and 4 at the 1,500MWe Francisco Perez Rios plant. Siemens evaluated the original turbine generator equipment, and helped evaluate the net present value and interest rate risk analyses needed to justify the project. It also planed the outage work with other subcontractors to assure on-time completion.
The company helped set targets and conditions for modernising the Instrument and Control (I&C) systems. It studied the possibilities for reducing fuel costs by increasing HP (High Pressure) temperatures, increasing returns by using frequency control,
and reducing losses for measures like optimised start-up.
Siemens provided the ASME-code superheaters, reheaters, waterwalls, low-NOx burners, regenerative air preheaters and boiler components.
The plant consequently reduced emissions to environmental compliance targets.
The company also completely upgraded the steam turbine train, rewound the generator stator, restacked the stator core, redesigned the condenser, and upgraded the cooling towers, instrumentation and controls.
MHI upgraded Unit 5, which was originally built by the company in 1982. The turnkey modernisation contract with CFE was signed through a special purpose company (SPC) established by Mitsubishi Corporation. The contract was signed in May 2004 and covers all construction work including civil engineering, equipment supply and installation.
POWER PLANT INSTRUMENT AND CONTROL (I&C) SYSTEMS
The I&C system of Units 3 and 4 were upgraded to a second-generation DCS (Digital Control System). First generation DCS were developed in the 1970s and introduced to the market in the 1980s. In the 1990s, I&C providers introduced a second generation of
DCS, with a higher portion of standard hardware or software components (suppliers ten years ago discontinued the first generation DCSs, and spares are now increasingly difficult to find).
Starting in 1996, CFE has been implementing an integral information system (SIIT, the Spanish acronym) for the overall plant. This system tells users the effect of plant operation outside the design conditions, using real-time information.
A new fuel
inventory system was installed in the second of five stages of the modernisation process, and development started of a heat rate monitoring system. The HMI (Human Machine Interface), design of deviation curves, specification of instrumentation, and data
acquisition system for the heat rate monitoring system are also complete.
CFE was however in 2003 fined for failing to meet its pledges to reduce emissions at the thermoelectric plant. Environmental agency Profepa imposed a MXN2 million fine. Francisco Perez Rios at the time had five coal-fired 300MW units, which started
operations between 1976 and 1982.
DOMESTIC ELECTRIC POWER CORPORATION
CFE has hydro, thermal, wind-driven and nuclear power plants. By the end of March 2005, CFE, together with the independent producers, had an effective rated generating capacity of over 46,000MW.
Of this, most comes from hydro (10,000MW) and fossil fuel (nearly 30,000MW). The rest comes from coal fired (2,600MW), geothermal (1,000MW), nuclear (1,300MW) and wind (2MW) power plants.