Coal plant gets new Parra chutes

A four unit, 2000 MW coal fired power plant in Ontario, Canada has had its aging coal transfer chutes replaced with a custom designed system that treats coal like water flowing along a smooth riverbed.

The decision to have a new system put in was taken after the owners of the Canadian plant, Ontario Power Generation, realized the coal chutes were causing significant problems and were in dire need of an overhaul. Friction from falling coal within the chute had repeatedly worn a hole in one of the diverters. The resultant spillage was affecting respiratory dust levels, while creating a combination of potential fire hazards.

“Everyday, members of our operations team had to clean up piles of coal dust that would collect beneath the aging coal transfer chute,” said Dave Cushing, Sr., construction technician at Lambton generating station. “This spillage was creating a hazardous situation for employees, while costing thousands of dollars each month in labour to clean up.”

New transfer chutes replaced the old ones that were installed 30 years ago
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Considered a ‘rock box’ style of coal transfer chute, Ontario’s old chutes bore the scars of continued maintenance as coal would continually pound certain areas as it would freefall through the rock box. This impact would repeatedly cause holes to develop and require steel patching.

The owners of Lambton contracted Parramatta Group to conduct an analysis of the facility’s two most problematic coal transfer systems and engineer and install a custom solution that would eliminate spillage and increase throughput. It soon became apparent to Parramatta’s designers that the two critical transfer points would have to be torn down and rebuilt from the ground up. If this was not difficult enough, for Ontario Power Generation, downtime was not an option.

Cushing said: “Complicating matters was a tight six hour window of opportunity to perform any repair work and reassemble the line without compromising our ability to provide electricity to our customers.”

Parramatta’s engineers used the company’s software to design a custom Controlled Flow Material Transfer System that would use extremely low angles of impact to control the speed and direction of the coal as it falls. Originating in Australia, the design treats coal like water flowing along a smooth riverbed. The result is a reduction of chute wear and tear, coal degradation and dust.

Ontario Power Generation’s 2000 MW Lambton coal fired power plant
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The design maintains the size and quality of coal pieces from the time they pass the inlet until they are channelled onto the delivery spoon. Control Flow also eliminates the need for impact beds and makes skirting optional.

Once both transfer chutes were installed, their impact was felt immediately. The amount of clean up required was reduced from occasionally a daily occurrence to a monthly or bi-monthly issue.

Cushing said: “The installation of these new coal transfer chutes has helped eliminate a potential fire hazard, improve air quality, and even reduced noise. These transfer chutes are doing everything we expected and should provide good, reliable and maintenance free service for many years to come.”

Furmanite overhauls 600 valves

Furmanite has completed a contract to overhaul some 600 valves at Wylfa nuclear power plant under budget, on schedule and up to all standards set by British Nuclear Group.

The work, which was undertaken during the scheduled outage, involved disassembling, lapping, inspecting and reassembling the gate, globe, check and safety relief valves in the station’s reactor area, turbine hall, gas circulators and boilers.

Most of the valves were lapped in-situ and not in the company’s workshop, helping the project to come in £100 000 ($177 750) under budget. Some 92 critical path valves that were taken to Furmanite’s workshop in Warrington, UK, were tested, witnessed by Royal Sun Alliance and approved, following an overhaul on the company’s test rig.

Furmanite worked on around 500 of the valves on site helping the project to come in under budget
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Overall, 30 technicians worked on the project over a six week period ensuring that the project met all critical path milestones in sequence.

Furmanite’s valve repair operations manager, Peter Gray, said: “Our highly trained and qualified technicians were key to enabling us to overhaul nearly 600 valves with zero re-work, contributing to on-schedule completion.”

The work was undertaken as part of Furmanite’s on-going valve maintenance and overhaul contract for British Nuclear Group reactor sites covering valve repair services for the nuclear generating sites at Chapelcross, Dungeness A, Oldbury and Sizewell A as well as Wylfa.

SNET installs FGD

SNET, the French subsidiary of Spain’s Endesa, has begun assembly of flue gas desulphurization (FGD) and denitrification systems at two 600 MW coal fired units – one at the Emile Huchet plant in Lorraine and one at Provenza plant in Provence Alpes Cote d’Azur. The installation is being carried out in order to comply with European legislation for large combustion plants.

The FGD system is a warm gas desulphurization (WGD) process that will reduce SOx emissions by up to 75 per cent and produce gypsum as a byproduct for commercial sale. A selective catalytic reduction system, which uses ammonia as a reducing agent, will control NOx emissions. The work on both units will be complete by 2008.

The project will require a total of 300 workers at each plant during the peak of the assembly period. The units will continue to operate during the process.

Fourth uprate for LM2500

GE Energy’s aeroderivative division has launched the fourth significant rating increase of its LM2500 aeroderivative gas turbine technology.

The 34.3 MW LM2500+G4 is an upgraded version of the LM2500+ and will deliver up to 12 per cent more power when compared to its predecessor over a range of operating conditions. GE said the latest up-rate would give customers additional horsepower with the same engine efficiency and reliability as the LM2500 range.

The +G4 can operate in both simple cycle and combined cycle operation, and will be available in standard and dry low emissions combustion models capable of burning natural gas, fuel oil or both. Compared to the LM2500+ in combined cycle mode, the +G4 is expected to have an 8.5 per cent power and 0.75 per cent heat rate advantage.