(a) Reduced fuel costs due to improved plant efficiency;

(b) Significant improvement of environment by reduction in CO2 emissions;

(c) Plant costs comparable with sub-critical technology and less than other clean coal technologies;

(d) Much reduced NOx, SOx and particulate emissions;

(e) Can be fully integrated with appropriate CO2 capture technology.

Supercritical technology and its advantages:

Since the energy crisis in 70’s a lot of effort has been made to reduce the energy consumption worldwide and increase the use of indigenously available fuels and renewables. In recent years also the need of reduced C02 emission from power generation has been a prime driver in developed nation’s energy policy. Thus, most of coal- fired power plants commissioned after 1980’s have been designed for supercritical operation with high efficiency ratings. Before the introduction of the super critical power plant concept, the generally applied concept was a drum-type boiler, which was replaced by the once-through type boiler to increase efficiency by at least 3% (relative) for practically the same investment.

In other words, supercritical power plants are highly efficient plants with best available pollution control technology, reduces existing pollution levels by burning less coal per megawatt-hour produced, capturing the vast majority of the pollutants. This increases the kWh produced per kg of coal burned, with fewer emissions.

Because of the above techno-economic benefits along with its environment-friendly cleaner technology; more and new power plants are coming-up with this state-of-the-art technology. As environment legislations are becoming more stringent, adopting this cleaner technology have benefited immensely in all respect. As LHV (lower heating value) is improved (from 40% to more than 45%); a one percent increase in efficiency reduces by two percent, specific emissions such as CO2, NOx, SOx and particulate matters.

“Supercritical” is a thermodynamic expression describing the state of a substance where there is no clear distinction between the liquid and the gaseous phase (i.e. they are a homogenous fluid). Water reaches this state at a pressure above 22.1 MPa. The efficiency of the thermodynamic process of a coal-fired power describes how much of the energy that is fed into the cycle is converted into electrical energy. The greater the output of electrical energy for a given amount of energy input, the higher the efficiency. If the energy input to the cycle is kept constant, the output can be increased by selecting elevated pressures and temperatures for the water-steam cycle.

Moreover, there are various operational advantages in case of supercritical power plant. There are several turbine designs available for use in supercritical power plants. These designs need not fundamentally differ from designs used in sub-critical power plants. However, due to the fact that the steam pressure and temperature are more elevated in supercritical plants, the wall-thickness and the materials selected for the high-pressure turbine section need reconsideration. The supercritical plant needs ‘once-through’ boiler, where as ‘drum’ type boiler is required by sub-critical power plant. In fact, once-through boilers are better suited to frequent load variations than drum type boilers, since the drum is a component with a high wall thickness, requiring controlled heating.

Moreover, fuel flexibility is not compromised in Once-Through Boilers. A wide variety of fuels have already been implemented for once-through boilers. All types of coal as well as oil and gas have been used.

Conclusion:

Thus, new pulverized coal combustion systems – utilizing supercritical and ultra-supercritical technology – operate at increasingly higher temperatures and pressures and therefore achieve higher efficiencies than conventional sub-critical units with significant CO2 reductions. The objective of power plants within toady’s market boundaries is more than ever to ensure high efficiency (to reduce the environmental impact as much as possible) while at the same time to increase their economics in competition to existing alternatives. The development of an economical and efficient concept needs to look at the steam turbine all other main components like boiler, flue gas cleaning equipment and the optimization of the water-steam-cycle as main parts for the optimization.

Current designs of supercritical plants have installation costs that are only 2% higher than those of sub-critical plants. Fuel costs are considerably lower due to the increased efficiency and operating costs are at the same level as sub-critical plants. Specific installation cost i.e. the cost per megawatt (MW) decreases with increased plant size. This plant concept fulfils the requirement to balance reliable power supply, sustainable use of existing resources and economic operation.

L&T Venture into Super Critical Power:

L&T has identified power as major growth area and recently entered into the two JVs with MHI, one for Boilers and other for Turbine Generators with the objective to bring world-class technology to India. Both the JVs have been signed for design and manufacturing of power equipment for use in supercritical power plants (which are superior to conventional sub-critical plants in terms of fuel efficiency and environment-friendliness).

L&T is also setting up manufacturing capabilities for other critical equipment, including pressure piping, coal pulverizers, ESPs, and heavy forging, which will streamline the availability of components, and increase overall plant reliability and availability.

L&T secured one of the single largest EPC orders in India’s power sector by winning a contract valued at Rs 6897 crores from Maharashtra State Power Generation Co. Ltd. (Mahagenco) for 3X 660 MW super-critical Boiler Turbine Generator (BTG) units.

Contributed by
P Nagaraja

(Based on an article by Mr Partha Das Sharma)

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We are happy to announce that dispatches of large-size Trunnion-mounted Ball Valves for the prestigious Single Point Mooring (SPM) project of HPCL Visakh Refinery have commenced. L&T had won this breakthrough order - for 10 nos motor-operated valves in sizes 48” and 36” - against stiff international competition.

We have positioned ourselves as a major player in the global SPM space by successfully executing this order.

MARIAPPAN  M, Chennai - 23 February
SHASHI KHANNA, Kolkata -  23 February
SATISH SHOLAPUR, Chennai - 24 February
RAMASUBRAMANIAN V, Chennai - 29 February
PREM KUMAR S, Chennai - 05 March
ATUL I MACWAN, Baroda - 06 March
SACHIN T PRABHU, Chennai - 09 March
PRIYADARSHINI, Chennai - 17 March
S S NAIKWADI, Powai - 17 March

1. MUKHOPADHYAY D , Dubai – 20th January
2. ABBI VISHAL RAKESHKUMAR, Powai – 22th January
3. BABU KURIAKOSE, Chennai – 23rd January
4. GOVI MAHALINGAM, Delhi – 28th January
5. MIHIR BUCH, Chennai – 2nd February
6. SUMIT KUNDU, Saudi Arabia – 2nd February
7. KALYANARAMAN S, Chennai - 3rd February
8. CHINTAN SHAH, Houston - 11th February

The first lot of 3-piece ball valves designed by Fluid Control Products Centre (FCPC) and manufactured at L&T’s facility in Coimbatore was dispatched this November to our stockists all over India. 

3-piece ball valves are manufactured in the size range of DN8 up to DN50 in both full bore and reduced bore designs. The order mainly consisted of ball valves of size DN15 and body material WCB.

The 3-piece design is ideally suited for easy online maintenance as the center portion can swing out eliminating the need to cut a valve out of line and having to replace both the valve and the pipe.

Supercritical is a thermodynamic expression describing the state of a substance where there is no clear distinction between the liquid and the gaseous phase. Water reaches this state at a pressure above 221 bar(22.1 Mpa) and temperature above 3740C.

The “efficiency” of the thermodynamic process depends on how much of the energy fed into the cycle is converted into electrical energy. If the energy input to the cycle is kept constant, selecting elevated pressures and temperatures for the water-steam cycle can increase the output.

Up to an operating pressure of around 190 bar in the evaporator part of the boiler, the cycle is sub-critical. This means, that there is a non-homogeneous mixture of water and steam in the evaporator part of the boiler. In this case a drum-type boiler is used because the steam needs to be separated from water in the drum of the boiler before it is superheated and led into the turbine. Above an operating pressure of 221 bar in the evaporator part of the boiler, the cycle is supercritical.

Fluid is heated in the supercritical state undergoes a continuous transition from a liquid-like state to a vapor-like state. There is no distinct temperature such as a boiling point in the supercritical state. Literally the word “boiler” should not be used for supercritical pressures and is rather known as steam generator, as no “boiling” actually occurs in this device.

In the 60’s the normal pressure and temperature for supercritical power plants (mainly in US and Japan) were around 245 bar and 540° C respectively, with only a few exceptions. In the 70’s, pressure was slightly increased to 250 bar with reheating temperature of 565° C, in most of the cases. In the 80’s, main steam
temperature itself was increased to 565° C. Since the beginning of the 90’s, steam pressure was substantially increased to 285 bar and temperature was raised in steps from 565° C to 580° C. The steam parameters in the new projects are even higher and exceed 600° C and 620° C with pressure of 300 bar (30MPa). There are few power plants operating at such high temperature/ pressure and are referred to
as Ultra Supercritical (USC) plants. In future further efficiency increase is expected to be achieved principally through the use of USC parameters by achieving live steam conditions of 760°C and 350 bar(35MPa).

Supercritical coal fired power plants with efficiencies of around 45% have much lower emissions than sub-critical plants for a given power output. Today’s state of the art in supercritical coal fired power plants permits efficiencies that exceed 45%, depending on cooling conditions. Options to increase efficiency above 50 % in ultrasupercritical power plants rely on elevated steam conditions as well as on improved process and component quality. An increase in cycle efficiency from 30% to 50% decreases CO2 emissions by more than 30%. This huge effect on environment makes a compelling case for both developed and developing countries to switch to Supercritical & Ultra Supercritical power plants.

Wishing a very happy birthday to all of you (below)!

1. SHANKAR R, Chennai – 23rd December
2. AJITH VINOD SIVAKUMAR, Chennai – 27th December
3. AMITABH ANAND, Delhi – 29th December
4. SOUMEN CHAKRABORTY, Kolkata – 29th December
5. PAUL ISAAC, Houston – 31st December

Wishing a very happy birthday to all of you (below)!

1. PRAVEEN ARORA, Chennai – 22nd November
2. GEOFFREY THOMAS F, Chennai – 2nd December
3. KUSHAL R, Chennai – 7th December
4. YUVARAJ P, Chennai – 8th December
5. MEHUL DESAI, Jamnagar- 11th December
6. ROHIT RAMACHANDRAN, Chennai – 12th December
7. SHAWN MENEZES, Chennai – 12th December
8. SHIVKUMAR A, Chennai – 12th December

L&T Valves has successfully initiated the frame of agreement with Saipem, a turnkey contractor in the oil and gas industry. This agreement will pave a way for increased business between L&T Valves and Saipem in European market in coming years.
 
The official signed agreement was handed over on 27th October 2009 in Chennai at a gathering comprising of officials from L&T and Saipem.

Saipem
1) Mr. Gianfranco Bellitto, Managing Director
2) Mr. Joel F.RUAUX, Director, Procurement & Subcontractiong Department
3) Mr. Andrea Merello, Procurement, Competence Centre leader
4) Mr. Karthikeyan K, General Manager, Procurement
5) Mr. Ramadoss R, Deputy General Manager, Procurement
6) Mr. Inderjit Sikand, General Manager, Piping
7) Mr. Ravi Teja V, Deputy General Manager, Piping
 
L&T Valves
1) A Shivkumar, Unit Head
2) SP Rajanish, Head International Sales
3) S Kalyanaraman, Head Domestic Sales
4) Mariappan M, Head Europeans Operations
5) Rahul Don Rudy H, Engineer Sales.