hot gas expander

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Hot Gas Expanders Enhanced design and upgrades for increased productivity GE Oil & Gas Global Headquarters Via Felice Matteucci, 2 50127 Florence, Italy T +39 055 423 211 F +39 055 423 2800 [email protected] Nuovo Pignone S.p.A. Americas Regional Headquarters 4424 West Sam Houston Parkway North Houston, Texas 77041 P.O. Box 2291 Houston, Texas 77252-2291 T +1 713 683 2400 F +1 713 683 2421 24-hour customer support Inside US: 866 GEOILGAS Outside US: 484 821 0400 For complete contact information, please refer to our website. ge.com/oilandgas The information contained herein is general in nature and is not intended for specific construction, installation or application purposes. GE reserves the right to make changes in specifications or add improvements at any time without notice or obligation. ©2010 General Electric Company All Rights Reserved Hot gas expanders Energy is the single largest operating expense for a refinery (accounting for about 50% of total cost), and energy waste from system leaks and inefficiencies can commonly be as high as 20%. Hot gas expanders can be used to recover otherwise wasted energy, particularly from the substantial heat generated in a refinery’s Fluid Catalytic Cracking (FCC) unit. An expander acts very much like the power turbine in an aeroderivative gas turbine. The flue gas passes over the nose cone of the expander and enters the stator vanes, which direct the flow onto the rotor blades. The rotor blades extract the energy from the gas and convert it into rotational energy that can be used to drive plant machinery. GE Oil & Gas solutions GE’s hot gas expanders are designed to get the most value from process waste gas – recovering considerable energy from both heat and pressure sources. Our optimized designs include special metallurgy and features to ensure long life for virtually any process conditions, and guarantee 4-5 years of uninterrupted run time. Advanced handling capabilities for highly corrosive FCC flue gas help reduce maintenance requirements and enable close alignment with other refinery equipment. An average 18-MW GE hot gas expander for power recovery can save approximately $9 million per year in refinery electricity costs, and avoid more than 244,000 metric tons of CO 2 emissions per year – two key reasons why the product line has achieved ecomagination certification. HotGasExpander_101510 GE imagination at work GE Oil & Gas GE_HotGasExpander_101510.indd 1 10/15/10 10:10:18 AM

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Page 1: Hot Gas Expander

Hot Gas ExpandersEnhanced design and upgrades for increased productivity

GE Oil & Gas

Global HeadquartersVia Felice Matteucci, 250127 Florence, ItalyT +39 055 423 211F +39 055 423 [email protected] Pignone S.p.A.

Americas Regional Headquarters4424 West Sam Houston Parkway NorthHouston, Texas 77041P.O. Box 2291Houston, Texas 77252-2291T +1 713 683 2400F +1 713 683 2421

24-hour customer supportInside US: 866 GEOILGASOutside US: 484 821 0400

For complete contact information, please refer to our website.

ge.com/oilandgas

The information contained herein is general in natureand is not intended for specific construction, installationor application purposes. GE reserves the right to makechanges in specifications or add improvements at anytime without notice or obligation.

©2010 General Electric CompanyAll Rights Reserved

Hot gas expandersEnergy is the single largest operating expense for a refinery (accounting for about 50% of total cost), and energy waste from system leaks and inefficiencies can commonly be as high as 20%. Hot gas expanders can be used to recover otherwise wasted energy, particularly from the substantial heat generated in a refinery’s Fluid Catalytic Cracking (FCC) unit. An expander acts very much like the power turbine in an aeroderivative gas turbine. The flue gas passes over the nose cone of the expander and enters the stator vanes, which direct the flow onto the rotor blades. The rotor blades extract the energy from the gas and convert it into rotational energy that can be used to drive plant machinery.

GE Oil & Gas solutionsGE’s hot gas expanders are designed to get the most value from process waste gas – recovering considerable energy from both heat and pressure sources. Our optimized designs include special metallurgy and features to ensure long life for virtually any process conditions, and guarantee 4-5 years of uninterrupted run time. Advanced handling capabilities for highly corrosive FCC flue gas help reduce maintenance requirements and enable close alignment with other refinery equipment.

An average 18-MW GE hot gas expander for power recovery can save approximately $9 million per year in refinery electricity costs, and avoid more than 244,000 metric tons of CO2 emissions per year – two key reasons why the product line has achieved ecomagination certification.

HotGasExpander_101510

GE imagination at work

GE Oil & Gas

GE_HotGasExpander_101510.indd 1 10/15/10 10:10:18 AM

Page 2: Hot Gas Expander

Improving your plant’s energy index

22 TBD 40 TBD 55 TBD 75 TBD 110 TBD

FCC Expander Frame Selection

FLUE GAS FLOW RATE lbs/sec

3.5

3.0

2.5

2.0

1.5

1.0

0 50 100 150 200 250 300 350 400

PR

ESSU

RE

RAT

IO

FCC Capacity(000 b/d)

FEX-81up to12 MW

FEX-97up to15 MW

FEX-107up to25 MW

FEX-126up to30 MW

FEX-142up to55 MW

Improved aerodynamic nose cone design Generator drive confi guration

FEX-125 power recovery train

Velocity of catalyst particles through rotor blades Mechanical drive confi gurationRotor blade contour map GE integrated systemVelocity of catalyst particles through rotor blades Mechanical drive confi gurationRotor blade contour map GE integrated system

For more information, please visit ecomagination.com

We also worked with our approved suppliers to procure and integrate the following elements:

• 72" and 58" process valves with independent, high pressure hydraulic actuation systems capable of closing in a fraction of a second

• 120" motor-driven isolation valve, for performing maintenance on the hot gas expander without taking the process offl ine

• Third-stage separator reducing the catalyst loading to the hot gas expander and ensuring long fl ow path erosion life

• Fourth-stage separator and storage hopper for dry collection of spent catalyst

• API lube oil system, including ASME code run-down tank

• Closed loop cooling system, including fi n-fan cooler and pump skid capable of providing 660 gpm (2,500 lpm) of water for heat removal

• Cooling and sealing skid to provide cooling steam and sealing air for the hot gas expander

Benefi tGE supplied St. Croix with a hot gas expander and generator to meet its power and environmental objectives. Deliverables included all control and auxiliary systems, and process valves required to produce approximately 26 MW of power. For environmental benefi t, our installation included a third-stage separator that can reduce particle loading of the fl ue gas up to 80% to help reduce stack emissions.

Our single source approach greatly simplifi ed the process for St. Croix’s engineering, planning and procurement personnel.

In 2010, the unit completed its fi rst uninterrupted fi ve-year campaign between maintenance cycles.

GE Oil & Gas provides specialized engineering services for hot gas expanders in the most challenging process conditions. Whether we’re building a new expander of our own design or uprating one from another manufacturer, our solutions are unique and highly reliable. Our innovative designs can satisfy all operating conditions including severe erosion, deposition, corrosion, performance defi ciencies and mechanical problems. For these reasons, they are the choice for the most demanding applications in the oil and gas industry.

Using the latest design and manufacturing technologies, we have improved every aspect of the hot gas expander. Our installed base continues to grow as more users become familiar with the signifi cant advantages of our machines – there are currently more than 150 GE hot gas expanders in operation around the world. Decades of turbomachinery experience enable us to design and construct hot gas expanders with the highest power levels, operating temperatures and pressure ratios in the world. Our units typically operate reliably with at least fi ve years between maintenance intervals.

Increasing the electrical capacity of a refi nery with zero emissionsChallengeAs refi neries expand and adapt to changing regulations, their demand for electricity can increase. This is especially challenging when the refi nery is located on an island where the plant energy consumption is four times the grid capacity. The St. Croix site needed an additional 50 MW of power and wanted to implement as green a solution as possible.

Solution Our hot gas expanders are ecomagination certifi ed products, which means they have passed a stringent qualifi cation process covering both production and environmental performance criteria. The units recover energy from the fl ue gas and are capable of reducing a refi nery’s Energy Intensity Index (EIITM) by as much as 7-10%.

We supply both mechanical and generator-drive confi gurations. In either case, reliability is key to maintaining FCC availability. For mechanical drive applications, we also integrate expander, axial compressor, steam turbine and/or motor into a single train. The generator drive mode has the added value that the hot gas expander can be taken offl ine without disturbing the process. We regularly install these expanders in new FCC units as well as during retrofi t of an existing unit for power recovery, as was done with the St. Croix refi nery.

We installed the following systems:

• Hot gas expander model FEX-142 capable of producing over 75,000 HP (55 MW) of power at an inlet temperature of 1400°F (760°C)

• Synchronous generator rated for 32 MW of power

• Switchgear, generator breaker, electrical controls, electrical distribution and power control room

• PLC-based control system to ensure availability of the FCC unit through transients and various modes of power recovery – fully automated start sequences and auxiliary vsystem controls

• Supervisory instrumentation and remote monitoring and diagnostic (RM&D) system, enabling advanced support by GE engineers

Hot gas expanders you can rely on Rigorous testing capabilities Case history

Performance-driven engineering1. Outer Casings

• Designed and manufactured in accordance with ASME pressure vessel codes

• Full solution and stabilization heat treatment for optimal structural margins and corrosion resistance

• Designed to withstand greater piping loads and to permit single lift of the entire outer casing assembly

• Upgraded fastener design and materials

2. Integral Stator Shroud• Increases expander effi ciency by 2-6% over cantilevered

stator designs

• Signifi cant reduction in nose cone stress levels (typically 40-60%)

• Easy removal from the back of the expander, eliminating the need to disassemble inlet or exhaust piping

• State-of-the-art chromium carbide coating on the entire pressure side and leading edge of stator vanes

• Special materials available to accommodate different high-temperature requirements, to reduce the effects of in-service aging and facilitate welding

• Designed for minimum fl ow-path erosion and deposition

3. Rotor Blades• Optimized airfoil aerodynamic designs for high effi ciency

and minimum erosion through the use of three-dimensional computational fl uid dynamics (CFD) software

• GE gas turbine technology applied in blade-to-disc attachment for low stress levels

• Increased structural and vibration margins due to reduced steady state and gas bending stress levels

4. Nose Cone• Improved aerodynamic design provides smoother

acceleration of fl ue gas and more uniform distribution of catalyst in stator vanes

• New inlet strut design minimizes aerodynamic losses and improves catalyst distribution and structural integrity

• Increased structural margins with weld neck support fl anges in optimum locations

• Full radiographic quality welds

5. Exhaust Diffuser• Highly effi cient designs through computational fl uid

dynamics (CFD) analysis

• Elimination of diffuser cracking and failures through Finite Element Analysis (FEA) of transient and steady state stresses, including diffuser natural frequencies

6. Upgraded Shaft Design• Increased stress margins and torque capacity from larger

journal diameters and coupling hub

• Shaft extends beyond the bearing housing to allow coupling installation or removal without bearing disassembly

All our hot gas expanders are tested for mechanical integrity by running the units at maximum continuous operating speed above 1,000ºF (538ºC) for four hours. Air at atmospheric pressure is heated in a recirculation loop by friction heating (windage) as it passes through the rotor blades. During this test, the hot gas expanders are also run at trip speed to verify operation of the over-speed trip system.

Other specialized testing available includes dynamic stress, structural vibration, performance, erosion, corrosion and metallurgical evaluations. These broad capabilities ensure you of the best possible design, coatings and materials solutions for your application.

Finite Element Analysis (FEA)Using the latest FEA software and advanced tools developed by GE, we optimize new designs and can safely push the design boundaries of your existing equipment. Areas of review range from transient heat transfer analysis of casings to steady state stress analysis of rotor blades and discs.

Computational Fluid Dynamics Analysis (CFD)We use CFD to design more effi cient fl ow paths while decreasing the effects of erosion and deposition. In conjunction with hot erosion testing, CFD enables us to predict fl ow path erosion and correlate it with fi eld data. Optimizing the fl ow path increases performance and reliability while reducing erosion and fl ow path deposition. In addition to our own equipment, we have analyzed and optimized fl ow paths of models by numerous other manufacturers.

Blade image analysisOur on-line blade photography and videography are economical methods of assessing the condition of a hot gas expander. Expert interpretation of the images enables us to draw conclusions about the operating condition of a hot gas expander. Scheduled maintenance can then be planned based on the actual condition of the rotor.

Hot gas expander sizingA properly sized hot gas expander provides peak power recovery. We offer fi ve frame sizes to match your process conditions and optimize your results.

Our fi eld performance questionnaire will help to properly size your hot gas expander. To request a copy or for further information, please visit geoilandgas.com

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1. Lube oil console2. Generator3. Gearbox4. Expander5. Expander discharge line (cold wall)6. Expander inlet line (hot wall)7. Third stage seperator8. Fourth stage seperator9 Flue gas from regenerator (cold wall)

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