Water success at Rijnmond energy center

Raw water with high and variable amounts of total dissolved solids, total suspended solids and periodic oil contamination, were just some of the challenges facing engineers as they designed the water treatment system at Rijnmond Energy Center in the Netherlands. Meeting the challenges head on, the team of Bechtel-Enka and USFilter designed and constructed a successful treatment plant that has been producing high quality water since November 2003.

The 1288 m3/h system supplies clarified cooling tower water and high purity boiler feed water at the new gas fired plant. The first plant built in the Netherlands by an independent power producer, Rijnmond will be one of the most efficient power facilities in Europe.

The raw water supply for the plant comes from a canal on the tidal Maas River. The total dissolved solids (TDS) level in the canal can fluctuate widely depending on the season, the tides from the Rhine, and the amount of water from the North Sea that ends up in the Maas River. In fact, the conductivity of the water ranges between 3000 and 10 000 mS/cm and changes between these extremes within a matter of days. The raw water intake is 20 m from a petroleum unloading pier in the Shell Oil Refinery. The ships and barges pulling in and out of the dock to support the unloading, stir up the bottom of the river.

“These conditions created an incredible challenge to us in designing the pretreatment portion of the system,” said Bill Willersdorf, director of corporate projects at USFilter in the US.

Four packaged steel clarifier systems were coupled together to handle a substantial flow rate, 1000 m3/h, to feed the cooling tower for the 790 MW combined cycle power plant.

One of four steel clarifier systems
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Meeting the challenge

The raw water treatment includes intake screening and pretreatment consisting of the four clarifiers and particulate and oil-absorbing cartridge filters. The high purity water treatment portion of the system consists of dual cartridge filters, two trains of double-pass reverse osmosis (RO) systems and two CDI-LX continuous electrodeionization systems with IP-LX modules from Ionpure Technologies. Other equipment includes a pre-coat condensate polishing system, chemical feed systems, solids dewatering systems, and associated pumps, tanks and controllers.

The intake screening system from USFilter Envirex Products removes rubbish and debris such as grass, seaweed and plastic bags from 27 m3/min of brackish water from the canal.

Tom Patterson, Rijnmond Energy Center project manager at Bechtel-Enka said, “USFilter combined a lot of the technologies it offers and coordinated with a number of suppliers in North America and Europe. Its success in this effort has contributed to the overall success of the Rijnmond plant.”

Besides handling the difficult intake water, the treatment plant also had to be designed with environmental considerations in mind. Due diligence was followed to protect the environment. In Europe, companies are self-reporting, which means that they, rather than regulatory agencies, are responsible for ensuring that the environmental protections are in place.

Another design consideration was the fact that the power plant had to export steam to Shell’s Pernis refinery, located next door. The treatment system had to meet normal plant water needs for the majority of the year and then ramp up production for steam host mode. The system is designed to operate as two independent high purity trains, with one train remaining on standby until needed.

The location of the energy centre presented many factors for consideration
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The CDI system skids at Rijnmond are high-flow, multiple-module systems consisting of 25 IP-LX modules per skid with a capacity of 85 m3/h each.

Exceeding specifications

The water treatment plant was started up in various stages beginning in November 2003, with the process completed in April 2004. Intergen, a Shell-Bechtel venture, declared commercial operation of the plant on June 20, 2004.

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Water quality from the high purity RO/CDI system is exceptional, with conductivity averaging less than 0.07 mS/cm. The sodium concentration in the RO/CDI product water is about 5 parts per billion (ppb) and the silica concentration is below 3 ppb. The system’s performance significantly exceeds the water quality specifications, which require conductivity of less than 0.10 mS/cm and sodium and silica concentrations of less than 10 ppb.

Bluetooth bites costs

Cambridge Consultants has delivered a prototype design of a Bluetooth-based radio module to the leading utility metering company, Actaris.

Based on a single-chip Bluetooth device, the module provides new opportunities to drive down the cost of remote metering, allowing meters to be wireless enabled at very low cost and opening the door to high integrity consumer activated schemes.

Using the new module, consumers with Bluetooth mobile phones, laptops or PDAs would have the option of taking meter readings themselves and communicating them to the utility company, providing a radical means for Actaris customers to cut their costs. The module also supports ‘walk by’ meter reading by utility personnel using low-cost commercially available devices such as smart phones.

Actaris is demonstrating and offering samples to clients world wide who are investigating remote reading.

Soft starters synchronise Central American wind farm projects

Working in conjunction with Spanish partner, Descarrollos Eolicos, Fairford has supplied hundreds of its QFE soft starters to bring wind turbine generators in several major wind farm projects in Costa Rica, Panama and Nicaragua, on-line smoothly.

They achieve synchronization to the power network without massive inrush currents on the supply, and without the harsh shocks that can damage and break mechanical equipment such as bearings, couplings and gears.

The soft starters prevent damaging inrush currents and harsh shocks
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The wind generator is driven to just below synchronous speed under the action of its aerodynamic rotor. At this point the QFE soft starter unit, is used to put the generator on line. The soft starter ramps the generator voltage up to the system voltage and as the generator accelerates further to synchronous speed, a by-pass contactor is closed by the wind turbine controller (WTC) once it has received a top ramp signal from the soft starter unit.

When the by-pass connector is closed, the wind turbine’s power factor capacitors are connected and the turbine rotor then accelerates the generator up to a greater than synchronous speed, allowing generation to begin.

The QFE soft starter units that perform this operation are Fairford Electronics standard 690V range. They are designed to reduce the magnetic inrush currents, which are an order of ten times rated line current when starting the generator direct on line, to about one times rated line current. The load current is not drawn by the generator while it is at synchronous speed. It is handled by the QFE controller until the by-pass connector is switched in.

Sweet innovation for bagasse mill

Peter Brotherhood Ltd, a specialist manufacturer of steam turbines, has secured a £3 million ($5.4 million) contract to supply Queensland-owned electricity supplier Ergon Energy with a 25.5 MW extraction condensing turbo alternator set.

The company will design and manufacture the geared turbine at its facility in Peterborough, UK. The complete unit will be tested on steam at the facility prior to delivery to the Isis Central sugar mill in the Bundaberg region of Queensland, Australia in 2005. The plant will be operational by mid 2006.

A 20 MW turbo alternator set designed and manufactured by Peter Brotherhood for a sugar mill in Zimbabwe
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The mill burns bagasse (the waste product that remains after processing sugar cane) to raise steam which is passed through the extraction condensing turbo alternator set to provide power and process steam.

This application is a very efficient method of producing power and process steam. The process is also environmentally friendly as the carbon dioxide emitted while burning bagasse is absorbed by the sugar cane crop. Approximately 65 000 MWh/y will be generated to help meet the growing demand around the Bundaberg region.

The turbo alternator set will comprise a multi-stage steam turbine and a gearbox, both of which will be mounted on a common bedplate. The AC generator and the complete water cooled condensing plant will be sub-contracted by Peter Brotherhood Ltd.

Biofuelled plant to Finnish company

Wärtsilä Corporation has been contracted to supply an 8 MW BioEnergy boiler plant by Isojoen Lämpö Oy in Isojoki, Finland.

The plant will incorporate Wärtsilä’s BioGrate combustion technology, which is especially suitable for burning extremely wet biomass fuel. The scope of supply also includes the process equipment, building, installation, commissioning and training. The plant will start producing in April 2005.

Wärtsilä’s BioGrate is especially suitable for burning wet biomass fuel
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The company Isojoen Lämpö, is jointly owned by Isojen Saha (a sawmill company) and the Isojoki municipality. The sawmill will use most of the heat provided by the new boiler in its drying line and the boiler will burn the side products from the sawmill such as, bark, sawdust and wood chips.

The local district heating network has a maximum heating demand of 1 MW during the winter. The boiler will burn side products from the sawmill: bark, sawdust and wood chips.

The company has an old biofuelled boiler which provides the heat for both the drying process and district heating. The heat supplied by Isojoen Lämpö has been 30,000 MWh / year.