Abstract — Power plant boilers need to be cleaned and inspected on a regular basis. Boiler chambers can be up to 50m high requiring scaffolding for all works on the water walls. The scaffolding itself can take several weeks. To overcome the disadvantage of the time consuming scaffolding work, an automated boiler wall crawler for wall cleaning and inspection is being developed by Alstom in collaboration with Alstom Inspection Robotics and Waterjet Technologies. The automated system will be able to drive up the water wall with the cleaning or inspection application integrated and no scaffolding will be required anymore. The cleaning application consists of a patented suspension cleaning technology where abrasive and water are mixed and pumped up to a defined pressure. The inspection will be done using latest ultrasonic technology to measure remaining wall thicknesses of the tubes. The deployment system consists of two magnetic track drives connected by a frame and two passive magnetic wheels. Laboratory tests have shown promising results. The system is able to drive up and down the water wall during the cleaning with the system running at around 100bar. Index Terms-- Automation, Maintenance, Power Generation, Reliability, Boiler, Safety, Robotics, Water Jet Cleaning, Inspection I. INTRODUCTION ower plant boilers are elements of thermal power plant used to convert the chemical energy of the (fossil) fuel first into thermal energy by combustion and subsequently transferring the thermal energy of the combustion gases into thermal energy of highly pressurized water. The water flows inside of armed pipes arranged at the inside walls of the boiler chamber. The boiler chambers can measure up to 35m x 35m x 50m. As an effect of the continuous combustion process the pipes are more and more covered by a layer of combustion residues. These pipes need to be inspected on a regular basis, mainly for wall thickness. Before a reliable inspection can take place, the residue layer has to be removed. As of today, this task is done manually using dry blasting method. The cleaning and inspection method require the installation of a scaffold at the Vera de Vries and Simon Honold are with ALSTOM Power, 5401 Baden, Switzerland , www.alstom.com/power Philipp Roth is with Waterjet Technologies Ltd, 5210 Windisch, Switzerland ,wwww.waterjet-technologies.ch Wolfgang Zesch is with Alstom Inspection Robotics Ltd. Technoparkstrasse 1, 8005 Zürich, Switzerland, www.inspection-robotics.com inside of the boiler in order to allow the personnel to access the wall. To reduce the cleaning and inspection time and to make this service task safer, a system is being developed to execute the working steps without scaffolding. The aim is to reduce the process time significantly down to a few hours or days. Also, the new system allows for recording the inspection data in order to make it available offline for further analysis. Fig. 1 Typical boiler of a coal power plant The inspection and cleaning system consists of a magnetic deployment device with an integrated cleaning or inspection application. It is able to crawl up the water wall, carry out the service task in a certain area and send the data back to the operator standing on the floor area of the boiler controlling the system. The benefit in using the new cleaning and inspection tool is mainly time saving and improvement of EHS (environmental, health and safety). In terms of EHS, working at height is not required anymore. The deployment device will be secured with a safety device, preventing the system from falling down in at any moment during service time. In terms of time saving, the main benefit is to avoid scaffolding. In many cases, only a partial inspection is required. For these missions, the impact on the time saving is even higher. The scaffolding for a partial cleaning and inspection task takes several shifts and requires up to 10 workers. Compared to the relatively short cleaning and inspection time for the partial area, this is quite time consuming. With the new system, the several shifts of scaffolding can be saved. Automated Boiler Wall Cleaning and Inspection W. Zesch, S. Honold, Ph. Roth, V. de Vries P
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Transcript
Abstract — Power plant boilers need to be cleaned and
inspected on a regular basis. Boiler chambers can be up to 50m
high requiring scaffolding for all works on the water walls. The
scaffolding itself can take several weeks.
To overcome the disadvantage of the time consuming
scaffolding work, an automated boiler wall crawler for wall
cleaning and inspection is being developed by Alstom in
collaboration with Alstom Inspection Robotics and Waterjet
Technologies.
The automated system will be able to drive up the water wall
with the cleaning or inspection application integrated and no
scaffolding will be required anymore.
The cleaning application consists of a patented suspension
cleaning technology where abrasive and water are mixed and
pumped up to a defined pressure.
The inspection will be done using latest ultrasonic technology
to measure remaining wall thicknesses of the tubes.
The deployment system consists of two magnetic track drives
connected by a frame and two passive magnetic wheels.
Laboratory tests have shown promising results. The system is
able to drive up and down the water wall during the cleaning
with the system running at around 100bar.
Index Terms-- Automation, Maintenance, Power Generation,
Reliability, Boiler, Safety, Robotics, Water Jet Cleaning,
Inspection
I. INTRODUCTION
ower plant boilers are elements of thermal power plant
used to convert the chemical energy of the (fossil) fuel
first into thermal energy by combustion and subsequently
transferring the thermal energy of the combustion gases into
thermal energy of highly pressurized water. The water flows
inside of armed pipes arranged at the inside walls of the boiler
chamber. The boiler chambers can measure up to 35m x 35m
x 50m. As an effect of the continuous combustion process the
pipes are more and more covered by a layer of combustion
residues.
These pipes need to be inspected on a regular basis, mainly
for wall thickness. Before a reliable inspection can take place,
the residue layer has to be removed. As of today, this task is
done manually using dry blasting method. The cleaning and
inspection method require the installation of a scaffold at the
Vera de Vries and Simon Honold are with
ALSTOM Power, 5401 Baden, Switzerland , www.alstom.com/power Philipp Roth is with Waterjet Technologies Ltd,