NEYVELI  LIGNITE  CORPORATION

Neyveli, Home of the Neyveli Lignite Corporation, is today India’s energy –bridge to the 21-century and a fulfillment of Pandit Nehru’s vision. Incidentally Pt.Nehru and NLC share a common birthday (14.11.1956) Pt.Nehru launched a mining operations with his golden touch in May 1957. Even since, there has been no looking back. NLC has achieved the objectives it has set for itself. Fulfilling its corporate mission to be the leader in the industry. Computing of two open cast mines, two pit head Thermal Power Stations, Briquetting & Carbonisation plant and a Fertilizer Plant, NLC’s growth is sustained and its contribution to India’s social and economic development is significant

MINES - I

Demarcated over an area of 16.90 Sq.km. with a reserve of about 287 million tones. Mine-I is situated on the Northern part of the field adjacent to the Neyveli Township. The lignite seam was first exposed in August 1961 and regular lignite mining was commenced in May 1962. Its production (6.5 million tones of lignite per annum) feeds Thermal Power Station-I, Briquetting and Carbonisation Plant and the process Steam Plant.

While the overburden thickness varies from 70 to 95 m, the lignite thickness is 10 to 23 m. German excavation technology in open cast mining, using Bucket wheel Excavators, conveyors and spreaders was used in this mine for the first time in the country, A huge reservoir of ground water exists below the entire lignite bed, exerting an upward pressure of 6 to 8 Kg/Sq.cm. which is tackled by an effective ground water management system.

MINES - II

Mine – II is located 5 Kms. South of Mine-I spread over an area of 26 sq.kms. with 398 million tones reserve. The lignite seam was first exposed in September 1984 and regular lignite mining commenced in March 1985. The maximum overburden is 103 m. and the lignite thickness varies from 8 to 22 m. Initially, the mine was started with a production capacity of 4.7 million tones and in February '83 the capacity was enhanced to 10.5 million tones per annum. The lignite production in this mine meets the fuel requirement of Thermal Power Station-II. The method of mining and equipment used are similar to that of Mine –I.


THERMAL POWER STATION - I

An opitome of India-Soviet collaboration, Neyveli-Thermal Power Station-I (TPS-I) was commissioned with one unit of 50 MM each and three units of 100 MM each.

The unique features of this power station.

First lignite-fired Thermal Power Station in South East Asia

First pit head Thermal Power station in India

First largest Thermal Power station in South India

Continuously achieving over 70% plant load factor, from 1982-83 to 1991.92 against the national average of around 50% and has continuously bagged the meritorious productivity award instituted by the Department of Power, Government of India.

The power generated from The Thermal Power Station is fed to the grid of Tamilnadu Electricity Board, the sole beneficiary.

THERMAL POWER STATION - II

Thermal Power Station-II (TPS-II) has been a major sources of power to all Southern states in India.

STATE POWER POWER
  In MW In %
Tamil Nadu 441 32.19
Andhra Pradesh 277 20.22
Karnataka 199 14.52
Kerala 153 11.17
Pondicherry 80 5.84
Unallocated 220 16.06
Total 1370 100

Balance 100 MW is used for NLC's consumption
Being shared by SREBs from time to time

The 1470 MW capacity power station consists of 7 Units of 210 MW each. The first unit was synchronized in March 1986. The second Unit of this Power Station was formally commissioned by the then Prime Minister Shri. Rajiv Gandhi. This Power Station has been series of technological innovations such as

Largest Lignite-fired thermal power station in India.
First and tallest town type boiler in the country (92.7 m. height)
First software based burner management system
First Hydrogen/hydrogen cooled generator of this size
First boiler to be cleaned by hydrofluoric acid
Steel structures used for the power house building
124 Meters natural drought cooling towards.

FERTILIZER PLANT

This Plant with a production capacity of 1,29,200 tones of Urea per annum, was commissioned in 1966. This plant is the first of its kind in India to adopt solid fuel gasification for synthesis gas production and in 1979 the plant replaced the fuel stock lignite with fuel oil.

BRIQUETTING & CARBONISATION PLANT

The B & C plant with production capacity of 2,62,000 tones of coke was commissioned in 1966. The plant produces coke from lignite which is sold under the popular trade name ‘LECO’. The coke produced in this plant is extensively used in the industrial sector because of its special properties. Currently ‘LECO’ is used in place of furnace oil and charcoal in both electro chemical and electro metallurgical industries. The by products produced in this plant like carbolic acid, ortho cresol, metapara cresol, xylenol, multivalent phenol and natural oil are used in various industries like pharmaceutical, chemical tanning, dye, paint etc.,

EXTENDING THE LIFE OF OLD POWER PLANTS BY L.E.P. OPERATION

The equipment of Neyveli Thermal Power Station-I were supplied, erected and commissioned by the erstwhile Soviet Union along with the NLC engineers between 1962 to 1970.

From the year 1980 to 1986m the power generation from TPS-I was always on the higher side… much more than the Southern region Power Station and all India level Power stations. And by that time many of the units of TPS-I have crossed more than 1,30,000 running hours.

The components of power plants are designated to withstand a predetermined number of load cycles and the normal safe operating life of a higher-pressure boiler is 1.8 to 2 lakhs hours. Scaling, corrosion, thermal creep and fatigue in the high pressure the temperature zones of the units render them unusable thereby reducing the service life of the plant.

At this stage, instead of scrapping the entire unit, NLC introduced a new technology called ‘Life Extension programme (LEP) in the old thermal power station. Extensive residual life assessment studies conducted by M/s BHEL in the late 80’s and early b90’s revealed that the high pressure parts had undergone metallurgical changes resulting in reduction in strength permanent creep damage, etc.,

HIGHLIGHTS ON L.E.P.

Critical components of the Boilers like super heaters, main steam lines, economizers are replaced/repaired.
Damaged blades, coils of LP & HP heater, high pressure valves etc. of the Turbine are replaced.
Upgradation of the class of insulation of stator and rotor winding, replacement of stator and rotor wedges and major overhaul of the Generator are undertaken.
Replacement of the insulation of the Transformer windings bushings oil etc and extensive overhaul of the Transformer carried out.

BENEFITS OF LIFE EXTENSION PROGRAMME

LEP costs just one eighth that of a new plant
Gestation period just 20% of a new plant
Cost of power generation will be lesser
Continuous power generation since LEP is taken in a phased manner
The same infrastructure is utilized fo0r the extended life
Increased capacity
Improved efficiency
Lower O & M requirements
Lower emissions.
Better reliability,
And it pays for itself.

REJUVENATION OF SPECIALISED MINING EQUIPMENT

The old mining equipments like bucket wheel excavators and spreaders are also being rejuvenated with a view to enhance the operating life of the machines. Most of the old equipments were bought in the sixties and they have served more than 1.25 lakhs hours. Now the equipment has been rejuvenated in a phased manner incorporating state of the art-technology like planetary gear drives for crawler and bucket wheel, introduction of belt drives with flush lubrication, eliminating conventional gear box with pumps fixed counter weights, modification of four belt system into two belt system in the spreaders etc.,]
By rejuvenation, a new lease of life of around 15 years has been given to these mining equipment

PROJECT UNDER CONSTRUCTION

Expansion of Mine-I

The present capacity of Mine-I (6.5 million tones) would be expanded to 10.5 million tones and the extra production will be fed to TSP-I expansion. LOI was issued for the purchase of specialized mining equipment

EXPANSION OF TPS-I

The present capacity of Mine-I (6.5 million tones) would be expanded to 10.5 million tones and the extra production will be fed to TSP-I expansion. LOI was issued for the purchase of specialized mining equipment

NEW MINE – MINE - IA

The plant load factor of the Thermal Power Station –I will be increased to more than 80% thanks to the life Extension programme. Accordingly, the Lignite requirement will also increase. In addition NLC has to supply lignite to M/s ST-CMS power plant. The Govt.of India has sanctioned to open a new mine (Mine-IA) of 3 million tones lignite per annum capacity… to meet the extra demand. Preparatory works are in progress.

ENTERING INTO THE NEW ARENA OF POWER CONSULTANCY

By completing the LEP exercise, NLC has emerged as a pioneer in carrying out the Life Extension Programame in India. With such a valuable experience on power plant and a wide exposure to Russian and German technology, the NLC engineers are capable of entering into the competitive field of consultancy especially on LEP of power plants. In addition to this, NLC proposed to extent its consultancy services for power houses planning, design and project report preparation, energy conservation on power plants, operation of power stations, chemical plants open cast, mining erection and rejuvenation of specialized mining equipments.

NLC, present the industrial giant of South India with a power generation capacity of 2070 MW and a lignite mining capacity of 17 million tones, per annum, is all set to expand its projects with a power generation of 4490 MW and mining capacity of 40 million tones per annum Encouraged by this success, NLC would venture into yet another challenging field of consultancy and work towards a bright tomorrow.