One (1) Power- Plant 110 MW, Coal- and Oil- fired

Thermal power Plant rated with 100 - 110 MW, manufactured 1965 and designed for firing coal and light - oil. The plant was scheduled to be operated for another 15 to 20 years, therefore the plant was modernised and refurbished in the years 1992 to 1997. Also a dry- adsorption- desulphurisation plant was installed and the burner system was modified to low- NOx- burners. Net- efficiency of the block is approx. 36 %.

Technical Data of the Plant

Coal Handling

The coal is reclaimed with pay loader from the storage stock and transported via belt conveyors to the 3 bins in the plant.

Steam- Boiler

Radiation- type boiler with forced circulation, membrane wall- casing, intermediate superheating, economiser and Ljungström- type- air preheaters.

Manufacturer Leading German

Nominal max. rating 320 t/h

Operating pressure in the drum 167 barg

Life steam after superheater 147 barg, 530^OC, 320 t/h

Interm. superheating 33,8 barg, 530^OC, 300 t/h

Feed water temperature 241 ^OC

Preheated air temperature 325 - 350^oC

Burner System

The coal is extracted from the 3 bins via speed controlled chain conveyors into the 3 bowl mills with static separators and from here feeded with preheated air to the 12 coal burners in 3 levels. Preheated secondary air is feeded below and above the coal lances.

Installed are 12 burners in 3 levels for burning gasoil (Diesel) as fuel for 100 % load or as support burners. The burner system was complete modified to a low N0x- sytem in 1995 to apply German emission regulations.

Auxiliaries for the boiler plant

The boiler plant is equipped with all auxiliaries, as mainly

Boiler feed water system with pre heater, degasifier, feed pumps (3 x 50 %), circulating pumps and condensate pumps.

Ash handling system for boiler ash with wet chain scrapper and conveyors

Ash handling system for flue- ash with storage bins.

Blowers for burning air and waste gas.

Deionisation and condensate polishing plant

Desulphurisation Plant

To reduce the SO₂ emissions acc. German standards, a desulphurisation plant was installed. It is a dry adsorption process with injection of limestone into the burning chamber of the boiler and quenching the waste gas before entering the bag- filter. The SO₂ - reduction with coal with 1,5 – 2,5 % sulphur approx. was > 60% and emission was below 400 mg/m^{3 SO}₂. We calculated and assume that SO2 – reduction comes up to 80 – 85 % with a sulphur content of 5 – 7 % in the coal.

Steam Turbine

The condensing type steam turbine is a single shaft turbine with 4 casings, intermediate superheating and 7 bleeds for feed water preheating.

Manufacturer Leading German

Type D4yT 2f 346, 3000 rpm

Nominal / max. rating 100 / 110 MW

Life steam 141 bar, 530 ^OC, 320 t/h

Interm. superheated steam 31 bar, 530 ^OC, 300 t/h

Condenser surface 6 300 m²

Condenser pressure 0,029 bar

Cooling water 14 200 m³/h with 12,5 ^OC

Auxiliaries for the Turbine

The turbine plant is equipped with all auxiliaries, mainly as:

Hydraulic control system for the turbine

Lubrication- oil system with pumps, cooler and filter

Condenser and condensate system.

Generator

3- phase generator with H₂- cooling system and exciter engine

Manufacturer BBC (now ABB- group)

Type WTH 882 sp, 3000 rpm

Apparent rating 200 MVA

Voltage 10,5 kV, 50 Hz

Exciter voltage 445 / 465 V

Control system and electrical equipment

The instrumentation and control system is renewed to a modern computer based control and reporting system.

Also the electrical switch gears and the MCC are modernised.

Transformer

Available are also the main- transformer 10,5 / 110 kV and the station transformer.

Condition of the Equipment

Due to professional maintenance and the extensive refurbishing in the 90’s, the plant is in excellent condition and ready to be operated for another 15 to 20 years without bigger repair works.

Mainly the following refurbishments were done in the late 90’s:

· Installation of a desulphurisation plant with dry adsorption

· Replacement of the electric precipitator filter with a new bag filter plant

· Modification at the burners for reduction of the NOx in the waste gas

· Replacement of all critical parts in the piping system for superheated life steam and intermediate superheated steam.

· Renewing of the H2- Generator cooling system

· Main refurbishing of parts of the generator

· Renewing of the control system, switch gear and MCC.

· Documentation modified to KKS-system and Drawings partly transferred to CAD- system

Availability

Plant is still in the cold reserve status, but available immediately.

Budget Price

As is where is: € 20,000,000.- net

FOB Dismanteling etc € 8,980,000.- net

Additional Information:

Fuel info:

For the fuel, important is

• The LHV which you can see is close to the design value. This indicates that with this fuel we can have the same heat rate/MW as designed for NZ. (this is normally a guarantee point for a new plant).
• The sulphur content is higher than designed value. The fuel type ie residue oil or waxy residue is normally produced with very low sulohur content (below 0.5 %), so please check again to see if this is correct.    In case it is, then it has two effects 1- First effect is the environmental effect, which depending on the country restriction may require a filter on the flue gas exhaust. 2- Second is the effect of corrosion, this can be modified by several methods on the FUEL SUPPLY SYSTEM (no modification is required on the boiler or burners), either mechanical or chemical.
• The viscosity again you can see it is much higher than heavy fuel oil, and this is why this type is also know as waxy residue.     Again this will need a small modification on the Fuel Handling System.

Conclusion:

This fuel type has already been investigated by Bechtel (designer of the plant) and found suitable as an alternative fuel with minimal modifications to the fuel supply system.

My conclusion is also the same and the cost is so minimal that can be neglected in respect of the total project cost.