Submerged Scraper Conveyor (SSC) System

Safe and economical way to remove bottom ash

With Alstom behind me... I’m in control

ALSTOM’S BOTTOM ASH CONVEYING EXPERIENCE | goes back as far as the early 1900s to our legacy company, Combustion Engineering – virtually pioneering the submerged conveying technology, both in the U.S. and Europe. We have built more than 100 Submerged Scraper Conveyor (SSC) systems around the world.

If you need to:

• Eliminate your ash pond or tank farm

• Extend time between outages

• Switch to problematic fuels

• Reduce maintenance costs

• Establish a smaller and “greener” footprint

• Create a safer working environment

an Alstom SSC is a cost justifiable solution.

With over 100 years of power service expertise, Alstom offers the unique ability to interface its ash technologies with every system in the plant. Alstom not only offers innovation, engineering expertise, and material fabrication, we also provide the logistics, project management and ongoing service and parts inventories required to keep your plant online.

INCREASING YOUR COMPETITIVE EDGE

Alstom keeps your boiler online...

REDUCES:• Overall maintenance costs

• Water consumption

• Electricity consumption

ELIMINATES:• Dewatering bins, sludge tanks, settling tanks

• Hopper gate house assemblies

• Hopper clinker grinders

• Hopper jets and slurry pumps

• Ash disposal ponds

RESULTS IN:• Additional revenue stream

• Fewer unplanned outages

• Safer work environment

INTEGRATED BOTTOM ASH SOLUTION

Reduces your plant footprint...

Plant Integration

ALSTOM’S SSC BOTTOM ASH SOLUTION GREATLY REDUCES MAINTENANCE COSTS | common to conventional ash handling systems. A well-engineered SSC replaces existing systems with a cost effective and less risky bottom ash solution.

An SSC reduces environmental risks of ash ponds and the costs of permitting, maintaining and dredging those ponds. An SSC integrated into other bottom ash systems reduces water usage by reusing most of the bottom ash supply water in the SSC. Power consumption is reduced by reducing the number of motors needed to power multiple high, medium and low pressure pumps used in traditional sluicing and dewatering systems. In addition, taking pyrites and economizer ash directly into the SSC reduces the maintenance costs associated with hoppers, piping, dewatering, and storing ash.

ELIMINATE UNNECESSARY EqUIPMENT

THE PYRITES SYSTEM | can be sluiced directly into the SSC while at the same time using the SSC’s water bath as a source for the sluicing water. This eliminates once-through water use and pyrites dewatering tanks.

ECONOMIZER ASH | can be transported to the SSC on dry drag con-veyors for removal along with the boiler bottom ash and pyrites.

A CLOSED LOOP WATER COOLING AND RECIRCULATING | is an option where water consumption must be minimized. With minimum makeup water required, the SSC water can be cooled and recirculated so that a minimum amount of water is used in the entire ash removal process.

ADvANTAgES:• No high maintenance

boiler sluice jet systems

• No dewatering tanks

• No boiler to pond piping systems

• No environmentally risky pondsrequiringextra maintenance

• Reduced parasitic power consumption

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SUPERIOR DESIGN/STATE-OF-THE-ART FABRICATION

Intelligent Components

ALSTOM UNDERSTANDS HOW ASH CAN DESTROY CRITICAL COMPONENTS. | Our design uses the thermal shock of cool water to cushion large slag falls and fracture them into manageable pieces. The cool water bath in the SSC provides the boiler seal in addition to quenching the hot ash as it is transported to a storage area.

Each SSC is manufactured based on customer specific site and ash rates. The planetary gear that provides torque for the chains and flights to drag the ash is designed with enough torque to pull out approximately 8 hours of standing ash. This idle storage time allows the SSC to be stopped for maintenance while the boiler stays online.

The conveyor chain is a high quality round link chain incorporating CrNiMo alloy case hardened steel to withstand wear in the abrasive conveying environment. Alstom’s unique design features metal guards to protect the chain strands and submerged wheels from damage from falling pieces of large slag and abrasive ash. Welded flight attachments, that are made of the same materials as the chains, are designed to snap into the chain for easy replacement while the boiler is online.

The conveyor is designed to operate at an optimal speed to extend the life of wear components and to allow for the dewatering of the ash on the unit’s incline section. If necessary, catch-up speeds can be used for times of heavy ash generation, such as soot blowing.

Advanced component design...

REduCEd PlAnt MAIntEnAnCE, lESS doWn tIME And IMPRoVEd SAfEty

STRUCTURALLY SOUND AND MECHANICALLY SUPERIORSUPERIOR DESIGN/STATE-OF-THE-ART FABRICATION

designed for safe operation...

COMMERCIAL READY ASH | In some cases the ash that isremoved using the SSC canbe used as an additionalsource of a plant’s revenue.

EASE OF MAINTENANCE | The SSC has side accessdoors to allow access tothe inside of the conveyor and provide access to theboiler for maintenance.

Structural Integrity

ENGINEERS AT ALSTOM HAVE DEVELOPED A PROPRIETARY ENGINEERING MODELING PROGRAM | to design an SSC specifically to your unique ash handling requirements. Once our modeling program has defined a unit’s performance requirements, it provides STAAD.Pro™ information for structural analysis of SSC members to calculate loads. Data is also provided using INVENTOR® software for 3D modeling of the unit for digital prototyping.

All structural components are designed to the latest edition of American Institute of Steel Construction (AISC) Code of Standard Practice for Steel Buildings and Bridges utilizing Allowable Strength Design (ASD). Each watertight SSC is fabricated of 3/8” to 1/2” carbon steel plate and is lined with replaceable, abrasion-resistant steel plates or basalt tiles to increase wear resistance and reduce wear and maintenance cost.

IMPROVED SAFETYAlstom’s SSC eliminates the need to rod slag falls that get trapped in bottom ash hoppers; unplanned outages due to blocked hoppers; and the injuries associated with clearing blocked hoppers.

Training and Technical Services

ALSTOM’S PROFESSIONAL TRAINING DEPARTMENT | will custom design a training program to ensure your operators are fully conversant with the operation of the Alstom SSC. We offer technical services consulting to make sure your SSC is fully optimized to your operation. Our technical services team is available to assist in implementing your system, especially at key times such as receiving materials, the beginning of construction, and at system start-up.

Replacement Parts… With Planned Inventory Support

ALSTOM’S INVENTORY MANAGEMENT PROGRAMS | offer material availability without the cost of carrying an extensive replacement parts inventory onsite. In consultation with you, we will create a total parts usage and lead time profile of wear parts, replacement parts, and emer-gency spares. Let Alstom define an inventory program to stage long lead time items optimized to your outage schedules.

THIS TIMELY, INDIVIDUALIZED PLANNING PROCESS | allows our customers to improve the outage planning process and reduce on-hand inventory levels – and costs – without impacting parts availability.

ALSTOM IS BEHIND YOU ALL THE WAY

AlSTOm’S COmmITmEnT: REduCE youR o & M CoStS

Reduce cost of ownership...

Alstom’s SSC pays for itself

AN ALSTOM SSC BOTTOM ASH REMOVAL SOLUTION IS A SOUND INVESTMENT | Alstom has created a Return-On-Investment (ROI) calculator to assist your organization in identifying your actual cost savings. Five easy steps can identify your ROI payback period based on your site specific operating data and financial resources. The simplified sample financial analysis chart at right illustrates our approach.

Step One – Site Specific InformationEnter your ash rates (TPH), water supply costs ($/GPM), internal parasitic power cost ($/KWH), and average assumed days of operation.

Step Two – Site Specific Energy UsageEnter your site’s bottom ash equipment energy usage, including high, medium, and low horsepower pumps;compressors; and clinker grinders.

Step Three – Annual Cost Burden Calculate your annual pond maintenance costs, plus your annual maintenance materials (hopper refractory gates, grinders, pipes, valves, bins and pumps), plus labor costs.

Step Four – SSC Solution CostPurchase cost (SSC, pyrites and economizer ash re-moval) plus installation cost estimate.

Step Five – Identify Your Annual Cost SavingsAdd up the costs in Steps One through Three.

Step Six – See Your ROI /Payback TimeApply your company’s cost of money (escalation rate and Internal Rate of Return) to get to your yearly savings and the pay back period.

Most SSC installations experience payback between two and three years. Ask your Alstom service representative for our ROI calculator. Our service managers will work with you to cost justify your investment.

SHORT ROI PERIOD

Step One – Enter your site specific information: •Totalbottom,pyrites&economizerash 18.5TPH •Assumeddaysofoperation 330 •Watersupplycost 0.005cents/gallon •Internalparasiticenergycosts 0.01cents/KWH)

Step Two – Customer Energy Usage: $11,325

Step Three – Common Annualized Costs: $652,000

Step Four – SSC, pyrites and economizer solution: $6,000,000 •ExampleSSCsolutionacquisitioncost($3,000,000) •ExampleInstallationcost($3,000,000)

Step Five – Annual Cost Savings: $2,350,429 (using an escalation rate of 4.5% and IRR of 7%)

Step Six – ROI: Payback in 2.5 years

Note: the calculation above represents real life site costs. Detailsofthesiteinformationthatwasinputareavailableuponrequest.

AVERAGE PAybACk In 2.5 yEARS

Alstom Power Inc. 2000 Day Hill Road Windsor, CT 06095-0500 Tel: 860.285.2100Fax: 860.285.3101 www.power.alstom.comPS

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