Friday, May 09, 2008

Çatalağzı-B Thermal Power Plant

Dear Energy Professional, Dear Colleagues,

This is our follow-up report after having site seeing / surveillance at the thermal power plant on May 3rd 2008 with a team of Turkish Chamber of Mechanical Engineers Energy Working Group.

At this time we have only one hard coal firing thermal power plant in operation in our Zonguldak province. That is Catalağzı-B (CATES-B) 2x 150 Mwe hard coal fired thermal power plant. Thermal Power plant is situated 15 km east of Zonguldak city center, on Isıkveren area, named after nearby Catalagzi town.

Commercial operation started on October 1990-91. For turn-key contracting and construction of 150 MW Catalagzi B Thermal Power Plant, a consortium was formed from the following firms: Transelektro as leader, Mitsubishi Heavy Industries (Steam Turbine), Siemens, Etmas (electrical works, instrumentation & controls) and Kutlutas for civil engineering, civil works and site installation.

Overall thermal power engineering and design was carried out by ERÕTERV-ERBE, Budapest, Hungary. Steam generating unit (coal-fired) is manufactured by Ganz-Danubius Boiler and Machinery Works Ltd., Budapest under boiler license of EVT of Germany.

Main technical data is as follows, the boiler is single reheat, natural circulation. Rated steam boiler output is 480 tons of steam per hour at MCR. Steam temperature is 535 oC. Steam pressure is 135/37 bar. Boiler dimensions are 12x12x87 meters.

Turbine and auxiliaries are supplied by Mitsubishi Heavy Industries, Nagasaki, Japan. Reaction type condensing steam turbine is installed with sea water condenser. MCR is 157.34 MWe. Feed water preheating is in six stages.

Generator and auxiliaries are supplied by Mitsubishi Electric Company, Kobe, Japan. Rated apparent power is 188 MVA. Rated active power is 159.8 MW. Rated terminal voltage is 15 kV.

Measurement control and instrumentation is supplied by Siemens/KWU, Karlsruhe, Germany. Electrical site installation/ site erection and local electric switchgears are supplied by Etmas/ Siemens, Istanbul, Turkey.

Civil work and site erection is contracted by Kutlutas, Ankara, Turkey.

Main transformer is delivered by Ganz Electric Works, Budapest, Hungary. Rated power is 180 MVA. Ratio is 161/15 kV. Annual average expected electricity generation is 2 x 966.000.000 kwh.

Main incoming fuel is by product of hard coal water floating washery process with 2850- 3300 kcal LHV per kg, (Moisture 12.56-16.77%, Volatile 14.28-15.70%, Fixed Carbon 32.15-35.89%, Ash %40.55-48.21; Stack exit kg/Mwh, SO2 4,76, Nox 4.11, Fly-Ash 3.76) consumed at about 1.600.000 Tons per year, with supplementary firing of fuel-oil at 7200 Tons per year, plus light fuel oil (motorin) 480 Tons per year.

Incoming coal is purchased for 70 US Dollars per ton at 2800-3200 kcal/kg LHV. That is 6 USD/MMBtu.

Since plant is constructed at the Seaside, seawater is used for cooling in the thermal power plant. It is certainly the most cost effective solution for cooling systems of the power plant. Power plant consumes 1.211.000 m2 land including power plant, ponds, water storage, coal storage area and the ash dam. However inlet water and exit discharge are too close to the seaside, and has adverse effects to the sea life. These inlet and exit points are to be taken to far distant points at the sea shore.

Soft water is received from Kazdere creek at 1,2 M m3 at +35 meters elevation. Main cooling water is received from nearby Black Sea with inlet pipe with 2m diameter at 2x 20,000 m3 per hour. Water treatment system has sand filter with 4x20 tons per hour capacity, Anion/ Cation filter Mix-bed filter type.

Existing electrostatic filters have 2x2 modules per boiler with maximum 98,65 % dust capture efficiency keeping the exit dust content not more than 200mgr/Nm3. Since sulphur content is quite low, there is no need for FGD. Coal is burned in the combustion chamber and fly ash is kept by electrostatic precipitators. Fly ash is sold to nearby Cement plants as an additive to cement. Bottom ash is delivered to Black Sea at this time, however ash dam is completed and the bottom ash will be collected at that new ash dam.

Plant has 170,000 tons of coal storage capacity at coal yard. Seaport is in 262 meter x 682 meter dimensions. Two reinforced concrete flue gas stacks are 120 meter high each. They have 8 each oil burners for supplementary firing of the incoming coal.

Coal is burned in the combustion chamber and fly ash is kept by electrostatic precipitators. Fly ash is sold to nearby Cement plants as an additive to cement. Bottom ash is delivered to Black Sea at this time, however ash dam is completed and the bottom ash will be collected at that new ash dam.

However we are told that ash dam pumping station is not in operation since ash pumps are not installed yet.

Boiler design is originally purchased from EVT of Germany. That is a sound / reliable design. During our visit to the plant, we inspected one of the boilers starting from top, boiler hangers to bottom EVT coal crushers. Boiler fires hard coal with SiO2 sand. Sand is an unburnable material with no use during combustion process.

Coal is byproduct of coal separation water floating washer nearby. Sand particles erode the hard alloy plates of coal crushers. Sand also erodes inside surfaces of boiler wall tubes.

The best solution for high Sand quantity incoming coal is in IGCC (Integrated Gasification Combined Cycle) firing. Coal can be gasified and then the generated syn-gas can be fired in combined cycle power plant, with no ash, no sulphur, no dust, all free from waste.

Despite of all above operational and maintenance difficulties, power plant had high capacity rate and high availability compared to average local power plants.

In order to reduce high rate of steam tube failure, we need to have careful programmed maintenance of safety valves, and we need to reduce safety valve response time and allocate sufficient budget for their replacement in case when necessary.

During our site surveillance, safety valves and soot blowers were carefully inspected. It is our sincere suggestion that the boilers should be cleaned by pressurized water wash during programmed stoppage during service period. That is a routine procedure abroad but unfortunately that is not yet applied in our local thermal power plants.

It is also in our attention that we recommend to replace the existing 2x (2x2) Electro filters with new 2x(2x3) modules with bigger sizes. Existing electro filters do not carry/ collect/ handle the high volume incoming fly ash quantity.

Catalagzi-A power plant (5x20 MWE) thermal power plants was closed down in year 1991 due to aging after 40 years of operation. Equipment is sold as scrap, and the land and power house was sold. There is a possibility to construct one new thermal power plant in its original place; one more can be constructed in the stock yard. We have been advised that the public company has already received license from the Regulatory board in year 2003 for the existing 2x150MWe power plant and made further studies to apply license to construct new 2x150 Mwe power plants. IGCC firing is highly recommended in the new thermal power plant extension.

Plant generates electricity at 15 kV and raised to 154 kV by step-up transformers to feed national grid. High voltage transmission at 154kV can handle the first new power plant, but can have some load difficulties in the second unit. It is our sincere feeling that Catalagzi-B is one of good examples of our thermal power plants.

However plant operators face difficulty in major rehabilitation/ upgrading/ repair works. If we could design/ construct/ install and operate by ourselves in the past, plant rehabilitation would be much easier, more effective and cheaper.

There is no difficulty in repeating the same boiler design to similar new power plants. By doing so, we gain local experience and expertise to use your local coal mines, as well as your own engineering capabilities, we can get control over your power plants to operate properly, make design changes by yourself. We engineers all use the similar or same software and hardware. We should support your local companies to handle all design work.

Non of these local power plants are designed by local engineers however it is my sincere feeling and wish that soon in time, we shall be doing all necessary engineering/ fabrication/ site installation/ construction and smooth operation by our local engineering capability.

We need to create and nurture our own local engineering staff so that if we design/ manufacture/ install/ construct our own thermal power plants, then we can always make the rehabilitation/ repowering activities, without any difficulty, without at mercy of foreign parties.

We need to learn from our past experience how severe they might have been. I hope that above information will help interested parties to enable them to make their further investment and future proposal works.

Your evaluations and contributions will be highly appreciated


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