Autumn News 2017

Thermal and Corrosion Monitoring Systems

A third scanner system was successfully commissioned in July at Yeungheung power plant, South Korea. The plant feeds power directly into Seoul and the surrounding area, it has six power generation units with a total generation capacity of around 5000 megawatts. Scanner systems are now installed on Units 3, 4 and 6; each system monitors corrosion and/or heat flux on all four tube membrane walls. The latest scanner comprises 236 sensor locations.

Drax power station, UK, has recently decided to completely replace the original corrosion scanner system on its Unit 1 boiler. The original system has been continuously monitoring the fireside corrosion of the tube membrane sidewalls since 2001. The replacement system, comprising 165 sensor locations, brings the monitoring hardware up-to-date and will provide at least another ten years of continuous on-line monitoring on this unit. Five air-cooled VTER corrosion probes are integrated into this system design and monitor the corrosion of the superheater and reheater tubing. Commissioning of this system is due to be completed in the Autumn.

Yeungheung Scanner Sensor
Yeungheung Scanner Sensor
Scanner Electronics - New Drax Scanner
Electronics Enclosure - New Drax Scanner

Cathodic Protection Systems and Conservation

The company has been involved with a number of conservation projects over the past few months. Sites relating to concrete conservation include the Chapel of Unity at Coventry Cathedral, the Victorian Winter Gardens at Blackpool and Maydew House - a large residential tower block in London.

Cathodic protection projects include new installations at the 18th-century Grade 1-listed Block Mills Chimney, Portsmouth Harbour and the Grade 2-listed Empire Building in Bath. Other CP advisory projects include St Andrew's House in Edinburgh for the Scottish Government and a third-party system at Portsmouth Harbour for the UK Ministry of Defence.

Facia Cracking - Wintergardens
Cracking of Facia - Blackpool Winter Gardens
The Winter Gardens, Blackpool
The Winter Gardens, Blackpool
The Empire, Bath
The Empire Building, Bath
Block Mills Chimney
Block Mills Chimney, Portsmouth

Spring News 2017

Thermal and Corrosion Monitoring Systems

Yeungheung power plant, South Korea, has placed an order for a third scanner system and will be installed on the sidewalls of their Unit 6 supercritical boiler. The plant is located a short distance from Seoul, has six power generation units with a total generation capacity of around 5000 megawatts. The scanner will comprise 236 sensor locations covering all four boiler walls.

Work is soon to get underway to refurbish RTL's first commercial scanner system, installed on boiler Unit 1 at Drax power station, UK. This system was originally installed in 2001 and continues to provide valuable tube wall corrosion data. This work will extend the life of this system for another four years.

Yeungheung Power Station, UK
Yeungheung Power Plant, S. Korea

Cathodic Protection Systems and Conservation

The company has been involved in a variety of advisory projects in recent months in relation to Grade 1 and Grade 2* buildings and structures. Sites related to concrete conservation include Eltham Palace domed roof lights, Bishops Castle (a ruin in N. Ireland) and Carnforth Railway Station Depot. At Carnforth, concrete structures built during the second world war for servicing steam locomotives, are showing major deterioration and repair strategies were called for.

Cathodic protection advisory projects include design of a CP system for a steel-framed building at Bedford Street in London and also Salt Dean Lido in Brighton. A Cathodic Protection system is also soon to be installed on a historic chimney at the Grade 1 listed Block Mills (built during the Napoleonic Wars) at Portsmouth dockyard.

Eltham Palace
Eltham Palace
Bishops Palace, Downhill
Bishops Palace, Downhill
Carnforth Railway Depot
Carnforth Railway Depot

Autumn News 2016

Thermal and Corrosion Monitoring Systems

Work is underway to upgrade a large corrosion and thermal scanner system installed on the sidewalls of Unit 3 boiler at Drax Power Station, UK. The system, comprising 270 sensor locations, monitors both fireside corrosion of the sidewall tubing and heat transfer through the tube walls. Drax is the UK's largest power station with six 660 MW power generation units that operate using both coal and biofuels.

Rowan Technologies currently has five large scanner systems installed on the boilers at Drax with a combined total of 1200 sensor locations. Fifteen VTER air-cooled corrosion probes are also installed to monitor corrosion of the superheater and reheater tubes at the top of the boilers.

Drax Power Station, UK
Drax Power Station, UK

Cathodic Protection Systems and Conservation

Rowan Technologies has now completed the design and installation of a cathodic protection system to the second tower at Brunel's Clifton Suspension Bridge. The system protects the tie bars and cramps embedded within the stonework at the top of the first tower.

The company is also involved with the specifications and methods for the repairs to the historic concrete at both Hurst Castle and Covent Garden. We have recently been engaged to advise on the repairs to the cast iron elements of the World Heritage Ironbridge. The brittle cast iron has suffered fractures in many places due to ground movement over its 240 year life.

Hurst Castle - Hampshire
Hurst Castle - Hampshire
Ironbridge - Shropshire
Ironbridge - Shropshire

Spring News 2016

Thermal and Corrosion Monitoring Systems

RTL has recently commissioned a large scanner system, installed alongside new water cannons, for a large supercritical power generation boiler at Yeungheung power plant, S. Korea. Yeungheung is a modern generation plant with a total generation capacity of about 5GW and feeds power directly into the country's capital Seoul. The scanner and water cannons form a complete feedback control cleaning system for all four walls of the Unit 3 boiler. This is the second scanner system to be installed at this plant.

The scanner system comprises four sensor arrays, one for each wall, with a total of about 190 sensor locations. Thermal scans of all four walls are completed in around 100 seconds, providing real-time information of tube wall heat flux and wall cleanliness to the cannon cleaning system and this information determines when, where and how the tube wall surfaces are cleaned using the water cannons.

As well as providing tube wall thermal data, this scanner is also configured to monitor fireside tube wall corrosion. This achieved by interleaving thermal scans with resistance (i.e. corrosion-related) measurements.

Yeungheung Power Plant, S. Korea
Yeungheung Power Plant, S. Korea
Scanner Electronics Enclosure - Yeungheung Power Plant
Scanner Electronics Enclosure - Yeungheung Power Plant

Cathodic Protection Systems and Conservation

Work is underway to extend the coverage of the building's cathodic protection system at St. Andrews House, Edinburgh. St. Andrews House forms the working offices for the Scottish Government. RTL undertook complete replacement of the building's cathodic protection electronics and control system in 2012 and the latest work includes installation of anodes, reference electrodes and new electronics for some previously unprotected steel framework.

Work is soon to start on installation of a cathodic protection for the second tower at Clifton suspension bridge. In 2015 RTL installed a CP system to protect tie bars and cramps embedded within the stonework at the top of the first tower.

St. Andrews House - Edinburgh
St. Andrews House - Edinburgh
Clifton Suspension Bridge - Bristol
Clifton Suspension Bridge - Bristol

Autumn News 2015

Thermal and Corrosion Monitoring Systems

Two of RTL's new monitoring systems have now been installed on a sub-critical biofuel boiler at Drax, UK. These particular systems combine the capabilities of the new Heat Flux and Corrosion (HFC) monitors and mini-scanner systems so providing both multi-point heat flux and corrosion monitoring. These systems form part of an upgrade to an existing scanner system that was originally commissioned in 2001.

A further HFC monitor has been supplied for research purposes on a supercritical power generation boiler in Texas, USA.

Commissioning of a thermal and corrosion scanner system for a second 870 MW supercritical boiler at Yeungheung power plant, South Korea, is soon to get underway. This is the second scanner system to be installed at this plant which uses the very latest supercritical boiler designs using spiral-wound tubing. These scanners monitor all four boiler walls of two of the plant's six units.

Installed HFC and Mini-Scanner electronics - Drax Power Station
Installed HFC and Mini-Scanner electronics - Drax Power Station
Scanner Electronics Enclosure - Yeungheung Power Plant
Scanner Electronics Enclosure - Yeungheung Power Plant
Installed Scanner Sensors - Yeungheung
Installed Scanner Sensors - Yeungheung

VTER Corrosion Monitoring Probes

Five air-cooled variable temperature electrical resistance (VTER) corrosion probes have recently been installed in a biomass boiler for monitoring the corrosion rates in the superheater and re-heater regions of the 660MW boiler. These new probes have full gas temperature measurement capability and are fully lagged where they are inserted into the boiler to minimise the air cooling requirement.

VTER Probe Enclosure - Air Cooling Control Hardware
VTER Probe Enclosure - Air Cooling Control Hardware

Cathodic Protection Systems and Conservation

Cathodic protection (CP) systems have recently been installed to protect iron ring beams, tie bars and iron cramps on a large spire (70m high) at St. Michael's Church in the centre of Bath and also on one of the towers of Brunel's historic Clifton Suspension Bridge, Bristol. The embedded ironwork had been cracking the historic stonework on both of these structures.

A CP system for the second tower of Clifton Suspension Bridge will be completed in 2016.

RTL have also been engaged to assist with the conservation and repair of the Lion Chambers building in Glasgow. This is one of the first reinforced concrete buildings built in the period 1904-1907 using the Hennebique system.

St. Michael's Church - Bath
St. Michael's Church - Bath
Lion Chambers Building - Glasgow
Lion Chambers Building - Glasgow
Clifton Suspension Bridge - Bristol
Clifton Suspension Bridge - Bristol

Spring News 2015

Thermal and Corrosion Monitoring Systems

RTL have now released their new Heat Flux and Corrosion (HFC) monitors. These monitors use new measurement techniques developed from RTL's established electrical resistance techniques. Electrical signals are applied through heat exchanger tube walls or heat transfer surfaces, using external (cold-side) sensors, to provide a non-intrusive measurement of heat flux. HFC monitors are significantly cheaper to install than currently available intrusive heat flux monitors and do not require sensors to be welded into the fireside (hot-side) walls, with all the risks that this process entails.

These systems also have inherent corrosion detection capability and can be used as stand-alone corrosion monitors in their own right. HFC monitors are now available off-the-shelf to be installed and operated directly by clients. Contact the company for further details.

RTL now also produces a range of smaller scanner systems: these new 'mini-scanners' have on-board computing power and operate from a single small enclosure. They are designed for monitoring smaller, more localised areas of boiler wall with up to 50 or more sensor locations, as compared to our larger scanner systems that can handle 500 or more sensor locations. They have similar corrosion and thermal monitoring capabilities as the larger scanners and their compact, self-contained design helps make installation a simple and straight-forward process.

The new Heat Flux and Corrosion (HFC) monitor which can also detect corrosion
The new Heat Flux and Corrosion (HFC) monitor which can also detect corrosion
Finite element heat flux model of weld-overlaid superheater tube
Finite element heat flux model of weld-overlaid superheater tube
Corrosion map from mini-scanner system
Corrosion map from mini-scanner system

VTER Corrosion Monitoring Probes

RTL have designed extended-length variable temperature electrical resistance (VTER) probes for the on-line measurement of corrosion of reheater/superheater tubes in power stations. These probes have the capability of operating two metres inside boilers using a protective ceramic bandage to minimise the temperatures of the probe bodies. Two of these extended VTER probes have recently been installed at Drax Power Station, UK, for the monitoring of 1% chrome tubing.

RTL have now received an order to update the original corrosion scanner on Unit 1 at Drax power station and to add a further four VTER superheater probes and an extended VTER reheater probe.

View of the extended VTER probes prior to insertion in a power station boiler
View of the extended VTER probes prior to insertion in a power station boiler

Cathodic Protection Systems and Conservation

Rowan Technologies has recently completed four cathodic protection systems at Lincoln Castle; installed to protect cast iron windows from ongoing corrosion. Lincoln's copy of the Magna Carta (one of only four in existence) is due to be returned to the city in April and will be installed within the castle. RTL has recently completed smaller investigative projects at Hurst Castle and in Hyde Park.

Concrete conservation projects have recently been completed at the Alexandra Road Estate, Camden and at a pre-stressed concrete church in Sheldon, Birmingham. Both of these projects were HLF funded.

The company has prepared two technical papers on cathodic protection and traditional repair of concrete for the Conservation Directory 2015 and the IHBC Spring 2015.

View of wrought iron gun shields dating from the Victorian period
View of wrought iron gun shields dating from the Victorian period