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Calderas Electrodos
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Electrode Boiler Technology Analysis prepared for New China Laundry
and
Swedish Trading Company
Electric Boiler Technology
Presentation Outline Elpanneteknik Overview
Company Overview and Capabilities Electrode Boiler Reference Plants
Electrode Boiler Technology Comparison Principles of Operation for Immersion-Type Boiler Comparison between Elpanneteknik and ZETA Boilers Principles of Operation for Jet/Spray-Type Boiler Comparison between Precision and CB/ACME Boilers Evaluation of Electrode Boiler Technologies with all four vendors
Elpanneteknik Boiler Proposal for NCL Group Proposed Steam Boiler Specifications Proposed Steam Boiler Plant Layout
Elpanneteknik Introduction Elpanneteknik is Swedish for Electric Boiler Technology and is
reflected in our complete line of resistance and electrode boilers. Elpanneteknik was established more than 15 years ago and is a
provider of numerous electric resistance/electrode boilers to many of the worlds Fortune 50 companies.
Elpannetekniks founders, Leif and Lars Kring, are both experts in high-voltage electrode boilers, each with more than 25 years experience in the design, installation and service of electrode boilers throughout Europe.
Elpannetekniks Engineering and Sales Headquarter is located in Nykoping, Sweden, 100km (1 hour) south of Stockholm.
Product LineWe only focus on offering two types of Electric Boilers: Electrode Boilers
Supply Voltage: 6 14 kV Power Output: 6 to 60 MW
Electric Resistance Boilers Supply Voltage: 380 690 V Power Output: Up to 6 MW
Electric Resistance and Electrode boilers are: ~99% Efficient with Zero-Emissions Extremely reliable with few moving parts Produce very low noise level during operation Able to take advantage of off-peak electricity rates
Company Details Quality System
Company complies with ISO 9001 Certification Audited and approved by Alstom and Siemens
Worldwide Presence Sales Presence in Europe, China and US Swedish-Based Factory meeting PED code
requirement for European Customers China-Based Factory to meet ASME / China
Pressure Code for Asian customers
Industries Served
Our Electric Boilers have been installed in a variety of industries including:
Nuclear Power Plants Mining Industry Marine Industry
Manufacturing General Industrial Use General Heating
Finlands Olkiluoto 3 Nuclear Plant
Max power: 2 x 15MW Supply Voltage: 10kV Steam capacity: 46,000 kg/h
Op. pressure: 12 bar Op. temperature: 192C
Elpanneteknik Auxiliary Steam Boiler Specifications
In 2006, Elpanneteknik was chosen to supply the auxiliary steam power plant to Finlands Olkiluoto 3 Nuclear Power Plant. While Frances Areva is the main contractor for the Nuclear Reactor, Elpannetekniks Electrode boiler plant is part of the turbine island, which is being managed by Siemens.The reactor is of the 3rd generation type with a power output of 1600MW the largest in the world.
Early in 2001, Framatomeand Siemens merged theirnuclear businesses to form Framatome ANP, with AREVA holding a 66% sharein the new company and Siemens holding 34%.
Olkiluoto 3 Aux. Steam Boilers
Elpanneteknik was commissioned by Siemens to provide the design, manufacture and installation of the complete Nuclear Power Auxiliary Steam Plant, which includes the following major items: Two Electrode Steam Boilers Feedwater tank with deaerator Dosing Equipment, Flash Tank, Silencers Pumps, pipes, service platforms, electrical installation
Auxiliary steam boilers for NPPs are used during startup and maintenance of the reactors to provide gland steam and heating.
Elpannetekniks Electrode Boilers were chosen for its high steam quality and purity, high stability during operation, high reliability, fast startup time, resistance to arcing and low maintenance requirement.
Olkiluoto 3 Plant Layout
Electrode BoilerFeedwater tank with deaerator
Protection Cage
Feedwater pumpsCirculation pump
Blowdown Separator
Silencer
Electrode Boiler at AstraZeneca
Electrode Steam Boiler at AstraZeneca: Installed Power: 1 x 25MW Supply Voltage: 11kV Design Temp: 240C Design pressure: 32 bar Steam rate: 38,000 kg/h
AstraZeneca is one of the worlds largest pharmaceutical companies.
AstraZeneca Control Cabinet
PLC: Siemens S7-400 HMI: Beijer Electronics (Mitsubishi) Touch Screen
HMI Touch-Screen Pictures
Other Boiler Installations
Weve provided more than 100MW in element (resistance) boilers throughout Europe: Element Boiler sizes up to to 6MW Design pressure from 6 50 bar[g] (0.6 5MPa / 87 725 PSI) Installed in power plants, factories, buildings, ships
Boliden Mineral
Alstom Marine
Volvo
Partial List of Customers
Electrode Boiler Technology
Electric Boiler Technology
Immersion Electrode Boilers
Outer Vessel
Insulated Inner Vessel
(neutral point)
Ceramic Insulators
Electrodes (3-6)
Steam Outlet
Standby Heater
Electrical Connections
PTFE Spreader Pipes (3-6)
Feedwater Inlet Spreader Pipe
PTFE Level Gauge Pipe
PTFE Blowdown Pipe
Inner vessel level control
valve (not shown)
Major Components - Immersion
Pressure Vessel and Inner Vessel The Boiler Pressure Vessel (outer vessel) is a pressure rated and ASME registered pressure
vessel. The Inner Vessel, which constitutes the neutral point, is electrically insulated from the outer
vessel and ground. This design limits the current to ground, should an unbalance between phases occur.
Electrodes and Ceramic Insulators The electrodes and water circulation system are designed and optimized to minimize wear
and eliminate arcing. The expected electrode life time is more than 10 years. When a change must be done, its only the electrode rods which need to be replaced. The electrode plate and bolts will last much longer.
The one-piece ceramic insulators are specially designed to resist electrical and water leakage and are expected to last more than 5 years.
Circulation Pump and Standby Heater The circulation pump transfers water form the outer vessel to the inner vessel and the level in
the inner vessel determines the power output of the boiler. There is a low voltage immersion heater in the outer vessel to maintain steam pressure and
water temperature of the boiler during standby for fast start-up and for avoiding material exhaustion when there are many on/off maneuvers, e.g. at so called off-peak operation.
Automatic Blowdown and Chemical Dosing The automatic blowdown system limits the conductivity of the boiler water. The blowdown
losses can be recovered by using our Blowdown Separator with built-in Heat Recovery System.
The dosing equipment maintains proper chemical content by adjusting the conductivity and pH.
Electrodes and Insulators
Water/Steam Flow Diagram
Steam Output
Blowdown
Outer Vessel
Recirculation and level control
Electrode RodInner Vessel
Blowdown
Feedwater and volume control
For Safety Valves
Ceramic Insulator
Ceramic Insulator
Circulation
Ceramic Insulator
Level Control Actuator
PTFE Circulation Pipe
Manholes
Control Valve
Principles of Operations - Immersion
Feedwater Supply Demineralized and deaerated water is pumped from the feedwater
tank into the outer vessel to maintain constant overall water volume. Water Circulation The circulation pump transfers the water from the outer vessel to the
inner vessel. For redundancy two pumps are installed. If the pump in operation fails, the other pump starts automatically.
Water level in the electrically insulated inner vessel is regulated by the amount of water pumped in and the inner vessel control valvethat allows water to drain out into the outer vessel.
Power and Steam Output Power and steam output is determined by the water level in the
inner vessel in contact with the electrodes and the conductivity of the water. Power can be regulated from 0% to 100%.
Blowdown Automatic surface blowdown maintains the appropriate conductivity
in the boiler water, and we expect efficiency loss with a blowdown recovery device to be less than 0.1%.
Elpanneteknik Immersion Electrode Boilers
High Electrical Stability Elpannetekniks Electrode Boilers have no problems with foaming and
arcing, because of the design, the requirement for demineralizedmake-up water and because of the strict control of boiler water conductivity.
Elpannetekniks Electrode Boilers have an electrically insulated neutral point (the inner vessel), with high resistance to earth (minimizing earth current short of around 10amps), therefore allowing our boilers to connect directly to the common electrical grid without using a dedicated grounded transformer.
High Steam Quality and Purity Elpannetekniks boilers are designed with steam quality in mind, with a
large steam space and boiler water surface (similar to fire-tube boilers) and low steam velocity that minimizes water droplet formation.
Our steam quality and purity is high enough to run turbines in Nuclear Power Plants, and can achieve steam quality of over 99.9%.
Due to our strict control in boiler water quality, we can assure a high steam purity with a low salt content in the steam (which otherwise can cause corrosion, coatings and other problems in connected equipment)
Elpanneteknik Immersion Electrode Boilers
High Reliability The only major moving parts in our system are our circulation
pumps and we can provide redundancy in the circulation system tomaintain a near 100% uptime.
Immersion Boilers are simple in concept and in operation and does not have complicated nozzle arrangements present in jet/spray-type boilers that wear out and require frequent adjustments to function optimally.
Elpannetekniks boilers meet the strict reliability requirements as dictated by Europes largest nuclear power plant operators.
Ease of Maintenance Elpannetekniks boilers have long-life and low-maintenance
electrodes and ceramic insulator designs and do not require external cranes to remove and service the boilers.
High Efficiency Elpannetekniks boilers utilize blowdown recovery device to
minimize energy loss due to blowdown. The overall efficiency, including blowdown losses, is more than 99.9%.
Immersion electrode boilers can operate from 0% to 100% power level with the same efficiency of close to 100%.
Immersion Electrode Boiler Safety Features
A-type alarm functions that shut down the boiler directly via power connection: HighHigh pressure (also disables heating elements) HighHigh water level in outer vessel LowLow water level in outer vessel Circulation pumps failure (both pumps) Alarms from 11kV switchgear (i.e. protection devices that trips the power
breaker) HighHigh conductivity Emergency Stop
Examples of B-type alarm functions that warn the operator, but dont shut down operation:
High pressure High water level in outer vessel Low water level in outer vessel Circulation pump failure High conductivity Signal out of range (for each 4-20mA transmitter signal)
Elpannetekniks advantages over ZETA Boilers
Elpannetekniks Boilers are similar to ZETA boilers from Zander & Ingestrom, but has been significantly improved in a number of ways, e.g.:
Leak-free gaskets, improved electrodes and ceramic insulators Elpannetekniks boilers benefit from significant improvements in our gasket designs, which
provide a leak free interface for our electrodes and insulators, reducing maintenance and downtime.
The ceramic insulators have been redesigned with higher-grade materials for maximum resistance to electrical and water leakage and offers longer wear-life.
The electrodes have been improved for increased life and improved current and wear characteristics.
The PTFE spreader pipes have been improved to optimize the flow to the electrodes and keep a leveled surface in the whole power range.
Improved control systems and HMI All Elpanneteknik boilers are offered using the latest, top of the line, PLC control systems and
HMI interfaces. The control panel is kept clean. All mechanical switches, except for Emergency Stop, are
replaced by virtual switches on the Touch Screen Operators Panel.
Only Electric Boilers and Approved for Nuclear Power Plants Finally, were not distracted by other lines of unrelated businesses with our singular focus of
producing the best electric boilers in the world. In that regard, the most significant vote of confidence in Elpannetekniks Electrode Boilers is our
recent contract with Olkiluoto 3 nuclear power plant from Germanys Siemens Systems
HMI FeaturesThe operator interface (HMI) is a touch screen, Beijer Electronics /
Mitsubishi, with the following functions: Overview picture of boiler plant, with animated process values and operational
conditions. Picture with operational modes and choices Pictures of controllers and controller parameters. Pictures for setting parameters, set points and alarm limits. Trend curves on pressure, steam flow and electric power (10kV to boilers). Alarm handling. Historic values of operational data.
External communication (e.g. to main control room MCR) is either done by hard wire, which provides the most important system data and functions for external start, stop and supervision of the system, or by PROFIBUS. Ethernet is also an option.
The traditional electrical switches on the control cabinet have been replaced by virtual graphical switches on a touch screen operators panel.
The only traditional switch on the cabinet is the emergency stop. Start and stop are done locally from the control cabinet, or remotely from the control room. Provided that certain functions are ready for operation, e.g. that make-up water, cooling
water and electric power are made available, and that all manually operated valves are in the right position, the system can be started automatically.
The start procedure will follow a sequence that is visualized on the operators panel. The stop procedure will also follow a sequence that is visualized on the operators panel.
Immersion vs. Jet-type
Jet-type BoilersPrecision
Improved Jet-type BoilersCB-ACME
Immersion BoilersElpanneteknik / ZETA
Jet-type Electrode Boilers Jet boilers were developed in Europe but no longer
manufactured there The original jet-type design was developed in Switzerland, but
currently is only being marketed in the US by Precision boilers and is distinguished by variable water pressure/water column in the nozzle header to control steam output.
CB/Acme Boiler is based on a modified design, also developed in Europe. The main difference is its use of a high-powered pump to maintain constant water pressure in the nozzle header and control output by covering a higher or lesser number of nozzles by means of a shield that is operated via drawbar and a motor actuator on top of the boiler.
Although jet boilers were developed in Europe, they are no longer marketed in Europe due to its low steam quality and nagging arcing issues.
Narrower but Taller Profile Jet-type boilers are narrower than immersion boilers because they do
not have an inner vessel, but jet boilers requires normally 1 to 2 meters additional installation height. A crane or other lifting device must be installed for maintenance and replacement of the nozzle header, which is a very space demanding job.
Jet-type Electrode Boilers Electrical Grid Compatibility Issues
Due to the lack of an insulated inner vessel and lack of high-resistance to ground, jet-type boilers should not be connected directly to the common electrical grid. The power company/distributor will normally require the boiler to be connected and directly grounded to (a costly) transformer, dedicated for the boiler only.
Jet-type Electrode Boilers are prone to arcing due to foaming problems and stray water sprays hitting the grounded vessel. Arcing has been shown to decrease transformer and breaker life, with increases in maintenance costs and intervals. Frequent trips of the power breaker are not appreciated by the operator as intervention to reset alarms and restart boiler is required each time.
(See http://www.electricity-today.com/et/june99/trans.html)The frequent energization as well as the number of short-circuits of the boiler were damaging
the contact points of the tap changers. Electricity Today, June 99
Accumulated heat and steam buffer Jet-type boiler has a very little water volume that can act as a buffer at
momentarily large or fast steam consumption. The Immersion type boiler has a large water volume which acts as a
steam buffer.
Jet-type Electrode Boilers
Steam Quality and Purity Jet-type boiler produces steam in the surface of the
water jets that strikes the electrodes. As the water surface where the steam escapes is so small, the velocity of the steam must be extremely high. Large amount of water droplets are then carried by the steam.
Jet-type boilers allow boiler water to accumulate a significant amount of dissolved solids, which combined with low steam quality, result in steam that carries high level of erosive and corrosive impurities that can damage downstream equipment.
Precision Electrode Boilers Precision Boilers are especially prone to arcing
The boiler controls output by varying the height of the water column (level) in the nozzle header.
As the water in the nozzle header is not pressurized, the spray pattern is not optimal. Often, stray water jets hit the grounded vessel resulting in arcing.
Precision has recognized arcing as a serious problem and has added shields and Teflon coating to minimize these problems but the durability, reliability and effectiveness of these fixes has yet to be proven. The underlying problem is still there.
Foaming is a problem in this type of boiler, much due to the acceptance of a high salt content. Foaming is one cause of arcing.
Internal Pump Design excludes Redundancy Precision Boilers HVJ-228 and up (> 7MW @ 11kV) have internal
pumps (of mixed flow type) and lack the ability to have redundant recirculation pump configurations - this can cause extended system downtime when the internal pump malfunctions.
If redundancy is required, external pumps must be used and they will require a certain minimum NPSH, which will increase required installation height and increase the installation cost.
C-B/ACME Electrode Boilers
Complex Jet-Knife Spray Control CB-Acme Boilers maintain a constant water pressure in the
nozzle header and regulates the amount of water spraying on the electrodes by using a shield and knife to block the unneedednozzles. This system ensures a better water spray pattern and reduces the risk for arcs.
The shield and knife system requires a relatively complex system of drawbar, stuffing box, motor etc, to raise and lower the nozzle-blocking shield. The system increases required installation height and also increases the need for maintenance.
Although arcing is not as evident in the early life of the boiler, the wear pattern of the nozzle can create arcing as the boiler ages.
Higher power consumption The constant high jet pressure creates elevated wear on the
nozzles due to constant pressure on the water jets and creates more wear and also results in increased power consumption from the circulation motor (power of motor is more than 4 times larger than in immersion boilers).
Competitive Analysis Reliability
Immersion Boilers are extremely reliable due to its simple design and redundant circulation pump arrangements.
The type has been proven in Process Industries and Nuclear Power Plants all over Europe. It is, and has been, the preferredtype of electrode boiler in Europe, with both customers and power distributors.
The largest electrode boilers in the world (70MW) are of the immersion type and are installed in European process industry.
Jet-type boilers have a greater need of service and maintenance, problems with foaming and arcing and thereforlesser availability.
Jet-type boilers produces a steam of lower quality and purity. This has mainly to do with a higher salt content and a higher rate of carry-over. (A demister and water separator, e.g. a cyclone filter, can handle part of this problem, but a steam superheater is not a solution as you will have problems with the steam superheaters elements).
Competitive Analysis
Serviceability Jet-type boilers require maintenance of the nozzle header and
they are accessed by lifting the full length of the nozzle header via an overhead crane on the top of the boiler, which increases headroom requirement of the boiler room.
Jet-type boilers have a greater wear on electrodes which must be changed at shorter intervals.
Immersion boilers dont require any extra space above the protection cage, on the top of the boiler.
Elpannetekniks boilers service requirement is limited to a yearly inspection and perhaps a change of insulators every 3 to 5 years. Electrode rods are expected to last at least 10 years andwhen a change is needed it is done inside the boiler, which is accessed through a manhole on the side of the boiler.
Competitive AnalysisGrid Compatibility
Immersion boilers, due to its insulated neutral point design, with a high resistance to ground, can be connected to the common electrical grid directly, reducing capital cost requirement of aseparate grounded transformer.
Precision / CB-Acme require a costly separate transformer because they have a grounded neutral design, with no current limitation to ground in case of dissymmetry faults that causes apotential in the neutral point.
Elpannetekniks boilers do not have foaming or arcing issues due to its design and feedwater quality requirements.
Jet-type boilers are prone to arcing which reduces transformer and breaker life, damaging contact points and tap changers.
Precisions boilers are regulating the power too fast and the power company complains of power oscillations which causes voltage fluctuations.
Competitive Analysis Efficiency
All electrode boilers are high in efficiency due to the principle of using water as a resistor, so whether its immersion or jet-type boilers, overall efficiency (including blowdown and insulation losses) are approximately 99%.
Steam Quality Immersion Boilers have extremely high steam quality of 99.5%+
and Elpannetekniks boilers can incorporate an optional internal demister that increases steam quality to above 99.8%, when required.
In addition, due to strict water quality control in immersion boilers, the resulting steam purity is much higher than in jet boilers, which means less corrosion, scaling and depositing on steam pipes.
Jet-type boilers have much lower steam quality and steam purity due to design with small steam evaporation surface, high steam velocity, high salt content and high rate of carry-over.
Competitive Analysis Summary
Elpanneteknik Immersion
Boilers
Precision Jet Boilers
CB-ACME Jet Boilers
Reliability & Availability High Low Medium
Grid Connectability High Low Low
Efficiency High High High
Steam Quality High Low Low
Serviceability High Medium Low
Steam Purity High Low Low
Proposed Steam Boiler Spec for NCL
Based on the specifications of 13 t/h of net steam output at 10 bar[g], we suggest the following: Electrode Steam Boiler, type ETSH10Mi, 9.1MW 11kV 12bar[g]
dimensioned for heating of makeup water, deaeration and blowdown losses.
Steam Boiler Dimension: 2.3m x H5.2m, incl. 150mm heat insulation (mineral wool covered with aluminum or steel plates).
Overall Height Requirement: 6.3m (includes requirement for a 1.4m x 0.7m x 1.1m deep pit)
Water-filled weight: ~ 14 tonnes High resistive neutral point for connectability to standard
common electrical grid. Overall efficiency of 99.9% with the use of a blowdown recovery
device and 50% condensate return
Summary of Differences Immersion Boilers characteristics:
High reliability and resistant to arcing Can connect directly to electrical grid High quality and high purity steam Lower and wider design profile Low maintenance requirement
Jet-type boilers characteristics: Requires maintenance to nozzles and jet shield and knife
mechanism and prone to foaming and arcing Requires a separate grounded transformer to connect to
electrical grid Low steam quality and steam purity Taller and narrower design profile Small, if any, steam buffer capacity High maintenance requirement
Presentation OutlineElpanneteknik Introduction Product LineCompany DetailsIndustries ServedFinlands Olkiluoto 3 Nuclear PlantOlkiluoto 3 Aux. Steam BoilersOlkiluoto 3 Plant LayoutElectrode Boiler at AstraZenecaAstraZeneca Control CabinetHMI Touch-Screen PicturesOther Boiler InstallationsPartial List of CustomersImmersion Electrode BoilersMajor Components - ImmersionElectrodes and InsulatorsWater/Steam Flow DiagramPrinciples of Operations - ImmersionElpanneteknik Immersion Electrode BoilersElpanneteknik Immersion Electrode BoilersImmersion Electrode Boiler Safety FeaturesElpannetekniks advantages over ZETA BoilersHMI FeaturesImmersion vs. Jet-typeJet-type Electrode BoilersJet-type Electrode BoilersJet-type Electrode BoilersPrecision Electrode BoilersC-B/ACME Electrode BoilersCompetitive AnalysisCompetitive AnalysisCompetitive AnalysisCompetitive AnalysisCompetitive Analysis SummaryProposed Steam Boiler Spec for NCLSummary of Differences
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