Allied Area Report

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ALLIED AREA TRAINING (G.T., S.T., H.E., P.E.D.)

Under the guidance of: Submitted by:

Mrs.Y.V.Rama Lakshmi Miss Surbhi Aggarwal

Sr.Manager ET/6119379 T&C Engineering T&C Engineering

(Compressor Engg) (Compressor Engg)

BHARAT HEAVY ELECTRICALS LIMITED

Ramachandrapuram, Hyderabad 502 0321.1 GAS TURBINE

BHEL Hyderabad is one of the Gas Turbine manufacturers in India; with the state-of-art facilities in all areas of Gas Turbine manufacture provide complete engineering in-house for meeting specific customer requirement.With over 100 machines and cumulative fired hours of over four million hours, BHEL Hyderabad has supplied gas turbines for variety of applications in India and abroad. BHEL Hyderabad also has the worlds largest experience of firing highly volatile naphtha fuel on heavy-duty gas turbines.

Different models:

[i] Frame 1:

Output: 5070 KW

Heat Rate: 3311 Kcal/KWhr

Dimension: 5.8 X 2.5 X3.4 m

Weight: 18 tons

[ii] Frame 3:

Output: 10450 KW


Dimension: 5.8 X 3.3 X3.8 m

Weight: 69 tons

[iii] Frame 5:

Output: 26300 KW


Dimension: 11.6 X 3.3 X3.8m

Weight: 84 tons

[iv] Frame 6:

Output : 39620 KW


Dimension: 11.6 X 3.3X3.8 m

Weight: 91 tons

[v] Frame 6 FA:

Output: 70140 KW


Dimension: 12 X 5 X4.4 m

Weight: 110 tons

[vi] Frame 9 E:

Output : 12340 KW


Dimension: 12.5 X 5 X5 m

Weight: 220 tons

1.2 STEAM TURBINE

BHEL Hyderabad has the capability to design, manufacture and commission steam turbines of up to 125 MW rating for steam parameters ranging from 30 bars to 300 bars pressure and initial & reheat temperatures upto 6000C. Steam Turbines are manufactured under technical collaboration with Siemens, Germany covering the whole rang of requirements for Drive, Cogeneration, Captive Power, Utility and Combined Cycle applications. BHEL Hyderabad is fully equipped to provide comprehensive service to clients covering system engineering, equipment design, and turnkey erection and commissioning.

Selection of Steam Turbine depends on the following:Inlet Parameters

Exhaust Parameters

Power Requirements

Type of Extraction

Feasibility of the model

Proneness of the Model

High speed / Direct Drive

Cost Economics

Availability of Existing Material/Stock material

Delivery periods of the machine

Inlet Parameters:

Size of Inlet section depends on inlet parameters. The velocities in stop and control valves have to be limited to ensure that pressure drop is with in limits.(Generally the inlet pressure drop shall be limited to 5%).Selecting 2 stop valves (i.e. 2 inlets) if required, thus reducing the size of inlet section thereby reducing the cost.H or N inlet section based on inlet pressure and temperature.

Exhaust parameters:

Condensing or Back pressure turbine, Select suitable exhaust pressure based on cooling water inlet temperature and maximum CW temperature rise permitted. Sometimes the exhaust pressure is specified by customer. Select suitable LP balding (for condensing turbine) for exhaust flow and exhaust pressure selected above by pitching at optimal exhaust velocity. For back pressure turbines, the exhaust section is decided based on exhaust velocity through exhaust flange.

Power Requirements

Selection based on flow or power criterion, optimal selection is done to ensure that best performance (Specific steam consumption/Heat rate), least cost, best deliveries are achieved. The selection is done to ensure that the turbine is capable of delivering the maximum power specified by customer under all valves wide open condition.

Type of Extraction:

Controlled / Uncontrolled

For controlled extraction turbines, data required are:

- Extraction flows (Normal, min and max)

- Normal / Maximum flow through control valves.

- ZER (Zero Extraction Rating).

Type of Extraction:

Feasibility of the Model:

The offered model shall be rotor dynamically suitable. Most preferred: The model is already offered for a similar rating. Documentation available with BHEL.

Proneness of Model:

Specific requirement by some customers like EIL/NTPC Model shall be in operation with similar parameters/rating.

High Speed/Direct drive:

Manufacturing cycle time is less for high speed turbines. High speed models are offered upto 40 MW only.

Cost Economics:Offered model shall be most cost competitive. Cost competitive models with slightly inferior performance are some times offered to bag orders.

Usage of Available stock / material:

First priority is given while selecting steam turbine to offer best delivery periods.

Steam Turbine Systems

Lube oil system

Steam &Drain system

Governing oil system

Condensate and evacuation system

Cooling water system

Controls &Instrumentation system

1.3 PIPING ENGG.

BHEL manufactures Seamless steel tubes for a wide spectrum of customers, ranging from Power stations, Petro-chemicals, Oil & Gas, Refineries, Sugar industries to Textile and Automobile manufacturers, as per National & International standards.

BHEL's capabilities in the field of manufacture of quality seamless steel tubes and pipes have been accorded recognition by reputed National/International agencies. These include Indian Boiler Regulations approval as a "Well known Tube maker and a Well known Pipe maker"; authorization by American Petroleum Institute, USA, to use their monogram on products conforming to API 5L specification and the Lloyds Register of Shipping, London, recognition as an "Approved Manufacturer of Steel Tubes and Pipes". BHEL also received ISO 9002 accreditation from Bureau Veritas Quality International (BVQI), London. BHEL ensures adherence to the respective standards and also caters to specific customer requirements.

BHEL's in-built quality checks from raw material selection to finished product ensures, each and every tube or pipe that rolls out is to meet various codes, standards and customer requirements. Some of the quality checks on finished tubes include the online-non-destructive tests (Eddy current/Stray Flux/Ultrasonic Tests); Hydrostatic tests and Mechanical tests (Tensile, Flattening, Flaring, Bend, and Hardness).

BHEL's sophisticated and unique facilities, manufacture both hot-finished and cold-drawn seamless steel tubes and pipes - in Carbon and Low Alloy steel grades. Seamless tubes and pipes of random or fixed lengths in a wide range of sizes (outer diameters: 19mm to 133mm and wall thickness: 2mm to 12.5mm) are offered. Edge preparation as per customer requirement is also done. BHEL manufactures Seamless steel tubes and pipes, high frequency Spirally Fin-Welded Tubes and Rifled Tubes. The BHEL manufactured spiral finned tubes find extensive application in waste heat recovery.

1.4 GENERATORS

BHEL presently has manufactured Turbo-Generators of ratings upto 560 MW and is in the process of going upto 250 MW. It has also the capability to take up the gas based and combined cycle power generation as-well-as for diverse industrial applications like Paper, Sugar, Cement, Petrochemical, Fertilizers, Rayon Industries, etc. Based on proven designs and know-how backed by over three decades of experience and accreditation of ISO 9001, the Turbo-generator is a product of high-class workmanship and quality. Adherence to stringent quality-checks at each stage has helped BHEL to secure prestigious global orders in the recent past from Malaysia, Malta, Cyprus, Oman, Iraq, Bangladesh, Sri Lanka and Saudi Arabia. The successful completion of the various export projects in a record time is a testimony of BHEL's performance.

(1) Small turbine generators: From 500 to about 2500 kW rated capacity, turbine generators will usually be single stage, geared units without extraction openings for either back pressure or condensing service. Rated condensing pressures for single stage turbines range from 3 to 6 inches Hga. Exhaust pressures for back pressure units in cogeneration service typically range from 15 psig to 250 psig.

(2) Intermediate turbine generators: From about 2500 to 10,000 kW rated capacity, turbine generators will be either multi-stage, multi-valve machines with two poles direct drive generators turning at 3600 rpm, or high speed turbines with gear reducers may also be used in this size range. Units are equipped with either uncontrolled or controlled (automatic) extraction openings. Below 4000 kW, there will be one or two openings with steam pressures up to 600 psig and 750F. From 4000 kW to 10,000 kW, turbines will be provided with two to four uncontrolled extraction openings, or one or two automatic extraction openings. These turbines would have initial steam conditions from 600 psig to 1250 psig, and 750F to 900F. Typical initial steam conditions would be 600 psig, 825 For 850 psig, and 900F.

(3) Large turbine generators: In the capacity range 10,000 to 30,000 kW, turbine generators will be direct drive, multi-stage, multi-valve units. For electric power generator applications, from two to five uncontrolled extraction openings will be required for feed water heating. In cogeneration applications which include the provision of process or heating steam along with power generation, one automatic extraction opening will be required for each level of processor heating steam pressure specified, along with uncontrolled extraction openings for feed water heating. Initial steam conditions range up to 1450 psig and 950 F with condensing pressures from 1 1/2 to 4 inches Hga.

1.5 Turbine Rotor Balancing

Since the turn of the century, steam turbine generators have earned an enviable reputation for economy and reliability in converting heat energy to electrical energy under the most exacting service conditions. BHEL provides engineering expertise to meet the challenges imposed in the design, assembly, and reliable operation of turbines of all sizes.

Capabilities include:

Nondestructive evaluation

Materials degradation studies

Remaining life assessment

Structural integrity analysis

Failure analysis

Materials evaluation and testing

Field hardness testing and replication

Vibration problem diagnosis

Telemetry testing

Vibration Control and Rotor Balancing

Using advanced techniques for field measurement, signal processing, diagnostic analysis, and other predictive tools, BHEL can identify and solve rotor, blade, and structural dynamics problems that put steam turbine generators out of commission. These techniques are used to solve field problems, while providing confidence at the design stage that turbine trains will exhibit low vibration levels. Analysis of vibration problems with rotating machinery and piping Steam turbine-generator rotor balancing Custom design of instrumentation and components for special applications Component testing of valves, pumps, pressure vessels, and instruments This on-site impact modal analysis equipment measures blade resonance and mode shapes. Shown here is a high pressure turbine rotor from a 580 MW unit undergoing static blade resonance testing .A low power laser and system continuously monitors changes in alignment between turbine and generator to define and solve vibration problems caused by misalignment. A portable spectrum analyzer is used in vibration surveys of turbine generator rotors. BHEL regularly performs these surveys to assist in rotor balancing.

1.6.) Some other important systems in steam power plant:-

GLANDS& SEALING SYSTEMS:-

Glands and sealing systems are used on turbines to prevent (or) reduce the leakage of steam (or)air between rotating and stationery components that have a pressure difference across them.. e .g. where the turbine shaft is extended through the cylinder end walls to the atmosphere . When the cylinder pressure is higher than atmosphere will be a general steam leakage outwards whilst if the cylinder contains steam below atmosphere pressure there will be leakage of air inwards and a sealing system must be used to prevent the air from entering the cylinder and the condenser.

As most of the steam leakage from glands does not pass through the turbine stages , a loss of power output is involved and every effort is made to reduce this power loss by an efficient arrangement of seals and glands. Three types of glands and seals are in general use on steam turbines , the carbon ring gland and the water seals. The first two glands act as restrictors to steam and air leakage ,whilst the water seal will prevent all leakage of steam and air. Pump glands are generally of the mechanical type .Clean water flushing is provided to reduce the heavy wear that would otherwise occur on startup after a lengthy shutdown. Conventional soft packing glands are used on the older smaller cooling water pump design.

LUBRICATION SYSTEMS:-

Oil is required by the bearing in order to provide a continuous oil wedge on which the shaft revolves , this requires only a small quantity of oil .However shaft conductivity , surface friction and turbulence set up in the oil produces considerable ,amount of heat and in order to keep the bearing temperature constant at the desired level a further quantity of oil is required to remove this heat. Oil is supplied to the bearing at a pressure from 5 to 25 lb/in2 gauge. This pressure is required to ensure that the pressure in the upper part of the bearing does not below atmosphere ,in which case discontinuities in the oil film would form .On the other hand if the pressure is too high the oil be sprayed out from the end of the bearing at a high velocity &will become finally atomized. In the conditions the oil may easily escape from the bearing house. The temperature of oil must be kept within certain limits. If the oil temperature entering the bearing is too low , in sufficient bearing lubrication will occur due to high velocity of the oil ,whilst if the oil temperature on leaving the bearings too high, this will lead to deterioration of oil due to high rates of oxidation. This temperature of oil leaving the bearing is limited to 1600F .So that the maximum temperature with the bearings not more than 1600F and required leaving temperature is achieved by adjusting the supply of oil to each bearing .

OIL PUMPS:-

Types of oil pumps

Main oil pump

Auxiliary oil pump

Jacking oil pump

Emergency oil pump

MAIN OIL PUMP:-

The main oil pump is invariably driven from the turbine shaft, either directly or through gears , to ensure maximum reliability .It may also provide high pressure oil for the relay system at a pressure of from 50 to 2000 lb/in2 usually by raising all the oil to this pressure the lubricating oil being drain off through a reduction valve .Although this method is often adopted because of its simplicity and because the relays automatically close the stop valve, if the lubricating oil supply falls it is wasted of pumping energy. Some turbines use a double gear pump having high and low pressure outputs, but on large turbines it may be advantageous to employ to separate pumps.

The normal type of pump used on turbines has been the gear pump. This requires no priming and provides positive oil displacement but must be driven from the shaft through reduction gear at about 400 RPM. The pump has two or three meshing gears.

On large turbines the quantity of oil used makes it economically to incorporate a centrifugal pump driven directly from turbine shaft. It is not self priming and requires oil ejector to over come the suction head both when starting and during running. When a separate governing hydraulic systems is used the oil lubricating system may be simplified by the adoption of ac motor driven centrifugal pumps. The pumps may be mounted directly in the main oil tank with their inlets submerged below the oil level thus obviating the need for an oil ejector.

AUXILLIARY PUMP:-

It is used for starting, stopping, and emergencies. It is sometimes driven by a steam turbine, but for some years the tendency has been to use a motor driven auxiliary pump feed with supply. The auxiliary pump is automatically brought into operation by a relay when the oil pressure falls below a certain value.

EMERGENCY OIL PUMP:-

It is invariably provided as a stand by the auxiliary pump. In the event of a fault interrupting the normal station or unit supply the d. c. pump which is fed from the station battery circuits in, thus ensuring the safety of the bearing whilst the turbine is brought to rest.

JACKING OIL PUMP:-

Supply of very high pressure oil provided by a small capacity positive displacement. Jacking oil is fed into the base of the bearings in sufficient quantity to establish each oil film on which the heavy rotors may float at very low speed of rotation, when the normal oil wedge would not be formed. The presence of jacking oil film whilst the machine reduces the torque required by the turbine motor and prevents the metal to metal contact damaging the bearings.

HEAT EXCHANGERS: -

A heat exchanger is any device used for affecting the process of heat exchange between two fluids that are at different temperatures. A heat exchanger in which two fluids exchange heat by coming in to direct contact is called a direct contact heat exchanger. Example of this type is open feed water heaters, de super heaters and jet condensers. The wall may be simple plane wall or a tube or a complex configuration involving fins, baffles and multiple passes of tubes. These units are called surface heat exchangers, are more commonly used because they can be constructed with large heat heat transfer surfaces in a relatively small volume and are suitable for heating cooling, evaporating or condensing applications. A periodic flow type of heat exchanger is called a regenerator. In this type of heat exchanger, the same space is alternately occupied by the hot and cold gases between which heat is exchanged. Regenerators find their application in pre heaters for steam power plants, blast furnaces, oxygen producers etc.

TYPES OF HEAT EXCHANGERS:-

Heat exchangers may be classified in several ways. One classification is according to the fluid flow arrangement or the relative direction of the hot and cold fluids. The fluids may be separated by a plane wall but more commonly by a concentric tube(double pipe) arrangement. If both the fluids move in the same direction, the arrangement is called a parallel flow type. In the counter flow arrangement, the fluids move in parallel but in opposite directions. In a double pipe heat exchanger, either the hot or cold fluid occupies the annular space and the other fluids moves through the inner pipe. Since both fluids streams traverse the exchanger only once, this arrangement is called single pass heat exchanger.

Another flow configuration is one in which the fluids move at right angles to each other through the heat exchanger. This type of arrangement is called a cross flow type. When large quantities of heat are to be transferred, the heat area requirement of the exchanger also becomes large. In this case multiple pass arrangements can be used.

1.7.) Project Engineering Department (PED):-

The Project Engineering Department (PED) of BHEL Hyderabad carries out system engineering for Gas turbine based power projects of the following types:

*Simple Cycle Plants covering Gas turbine units and their auxiliaries for power generation.

*Cogeneration Plants covering Gas Turbines & Heat Recovery Steam Generator (HRSG) for power and steam generation.

*Combined Cycle Plants covering gas turbines, HRSG and steam turbines for combined power and steam generation.

PED carries out system engineering for the project, by integrating the products supplied by the unit, sister units and Balance of Plant (BOP) packages sourced from outside, along with facilities provided by the customer to enable fulfillment of performance requirements of the plant. The civil, mechanical, electrical and C&I scope of works connected with the projects is broadly described below:

Civil sub group of PED :- This deals with civil engineering works for gas turbine based power projects, steam turbine, compressor, oil and gas processing projects. The scope of work varies depending on the type of contract viz, where entire civil works from tendering to design execution are included to specific equipment - based civil engineering design such as foundation, structures for deaerators, pipe racks etc.

Mechanical sub group of PED:- This executes projects to meet specific customer requirements with reference to steam parameters, fuel availability, plant layouts etc for gas turbine based power projects and involves interface engineering with customer/consultants, sister units of various suppliers and other engineering groups within the unit.

Electrical subgroup of PED :- This carries out system engineering for gas turbine based power projects specific to contract, right from hooking up/drawing power from local grid to ensuring reliability of power supplies to all equipments, catering to power plant auxiliaries and customer house loads. This calls for an integrated approach wherein reliability, economics and satisfactory operation are balanced optimally and involves interface engineering as stated above.

C&I subgroup of PED :-The deals with various activities relevant with Controls & Instrumentation System engineering, engineering of bought out items, layouts preparation, interaction with sister units and also internal engg groups. Responsible for the Design of Control Philosophy for the overall Plant in line with the customer specification requirements.

Contract closing subgroup of PED:-deals with contract closing issues like closing of punch points raised by customer, supply of pending supplies, generation of as built documents and commercial settlement for any balance engineering items.

PED OBJECTIVES:-

To meet the Companys Quality policy and Quality objectives, the following objectives are defined: Customer satisfaction through timely execution of design documentation for BOP packages and system engineering. This is ensured by: Customer documentation schedule aligned to the Overall Project schedule. Critical documents submission within the agreed schedule and clearance from customer obtained within 4-6 weeks of submission so that downstream detailed engineering and procurement can proceed smoothly. List of such documents /drgs are elaborated in the description of activities of the respective disciplines. Revision of documents / drawings incorporating customer comments within 4-6 weeks.

Satisfactory performance of the packages and products to meet customer specifications including statutory and regulatory requirements. This is ensured by: Procurement of bought out packages based on the customer approved Vendor list. Submission of sizing criteria/ calculations to the customer and obtaining approvals as per agreed documentation schedule. Review of purchase specifications for ensuring the incorporation of project specific requirements. Settlement of Vendor specific deviations with the customer for critical packages. Updating of Package purchase specifications to meet customers present and future requirements. This is ensured by incorporation of the following into the procurement specs and sizing documents: Project specific requirements. Clear terminal points with specific details, for packages covering hookups with customer facilities. Contract stipulated margins in sizing, wherever packages are to cater to the customers non-power plant requirements also. Outcome of the completed improvement projects.

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