Variable speeds and ease of configuration top actuator demands

Paul Boughton

Advanced actuation technologies that have variable speed capabilities allow users to configure each device so that they support a wider range of requirements. Eugene McCarthy reports

German company SIPOS Aktorik has secured a power industry contract for around 1000 electric actuators to be commissioned at a new ultra-supercritical (USC) coal-fired power plant in Opole, south-west Poland. The contract follows an earlier order for around 1000 actuators for the Kozienice II coal-fired plant, also in Poland.

SIPOS devices with conventional control and PROFIBUS DP V2 interface for plant engineering and diagnostics were chosen for the Opole project. Key reasons for the selection, says SIPOS, were its strong credentials in the power industry, advanced actuation, variable speed capabilities and the ability to configure each device to support a wide range of requirements.

Alstom is responsible for overall project management, design and commissioning of units five and six at the Opole scheme. Unit five is due to enter commercial operation in 2018 and unit six in 2019.

SIPOS’ actuators, supported by the company’s local partner AUMA Polska, will be adopted throughout the new Opole plant, which comprises two 900MW units. The USC will be Poland’s largest hard coal-fuelled facility which, when operational, will supply electricity to the equivalent of two million homes. First deliveries of the actuators to the Opole plant are planned for the second quarter of 2015.

SIPOS devices also have proven successful in aiding cooling water top-up processes at the Callide B power station located near Biloela, in Central Queensland, Australia. 

The coal power scheme has eight steam turbines, with a combined generation capacity of 1720MW. Steam is condensed using conventional cooling towers fed from a cooling water pond. The pond water top-up system at Callide B comprises a level sensor and control valve operated by a SIPOS 5 PROFITRON actuator with integrated process controller. By providing intelligent actuators, external process control was not required thus simplifying the system and saving capital and installation costs.

Water from the pond at the bottom of the cooling tower is continually lost through evaporation. The water level therefore needs to be topped up from an external source, in this case from the Awoonga dam and Stag Creek pipeline. A simple control system was required to activate and modulate the top-up valve to control the pond water level. SIPOS’ actuation technology, featuring integrated process control functionality which accommodates a range of setpoint control possibilities, met the requirements of the scheme.

In other news, specialist modular electric actuation company AUMA has been contracted to supply over 200 actuators to aid automation at a new Polish combined cycle gas turbine (CCGT) power plant. Located in the industrial city of Stalowa Wola, the scheme is part of an initiative by the Polish government designed to reduce the country’s dependency on coal for electricity generation.

With an estimated opening date of late 2015, the plant will produce 450MW of electric power. An additional 240MW of thermal output will be generated to provide district heating for the city’s 65,000 homes. With a thermal efficiency rating of 60%, the power plant will be one of the most efficient in Europe.

Stalowa Wola is a particularly prestigious for AUMA as European Investment Bank officials who have contributed to the funding of the project have advised that the plant will demonstrate the feasibility and benefits of CCGT technology in reducing the country’s carbon footprint.

In another project success, AUMA says its capabilities in commissioning and retrofit actuation projects, along with an ability to tailor its technology, were key selection criteria for the company securing a major order from Helsingin Energia, one of the largest energy companies in Finland. 

One hundred and fifty latest series AUMA actuators, equipped with integrated controls, have been installed in the Vuosaaren A-voimalaitos power plant to aid valve automation.

Additional reasons for Helsingin Energia selecting AUMA over other actuator suppliers were the actuator manufacturer’s proven skills providing actuation solutions, and the scale of its operation, which confirmed its capability to handle the demanding scale of the order and delivery time frame. Also important was AUMA’s ability to provide all the actuator commissioning services within just three weeks: the rapid response minimised the considerable expense and inconvenience of plant downtime.

The actuation brief included replacing all existing actuators and automating manually operated valves. Demonstrating the adaptability of its modular design, AUMA produced custom-made mounting brackets and adaptors to meet the installation’s precise dimension requirements.

AUMA’s subsidiary for the region, AUMA Finland, has been established for 40 years and local staff  provided comprehensive commissioning assistance: new devices were mounted onto valves and existing actuators modified to support the needs of the site’s new automation system.

Helsingin Energia meets 90% of the heating demands of Helsinki. The overall production capacity of the plant is 160 MW from electrical power and 160 MW from district heating.

Meanwhile, new from Smith Flow Control is the EasiDrive portable valve actuator. Described by the company as possibly the most versatile valve operation tool available, it can be carried in a rucksack and is specially designed for use with valves requiring a large number of turns or which are otherwise difficult to operate because of high torque or harsh climate conditions.

With the EasiDrive the operator has absolute control when opening and closing different sized valves with varying torque requirements. One person can efficiently drive banks of valves with a single tool, reducing fatigue and risk of injury and resulting in major cost and time savings. It can be used in virtually any industry, from oil refineries and petrochemical plants to power stations and paper mills.

Among EasiDrive’s key features are: no permanent power supply required; suitable for all climatic conditions; ideal for moving tight or partially-seized valves; eliminates operator fatigue and greatly reduces the risk of injury; and none of the ‘kickback’ often associated with other torque devices.

The ‘reaction kit’, which prevents a torque kickback, is especially useful as valve movement is always fully controlled, preventing operator injury and fatigue. In addition, the variable torque output feature, which prevents excessive torque being applied, ensures proper and safe valve operation at all times.

EasiDrive can be powered by air, electricity or battery, giving the user ultimate control over the preferred choice. It can also be custom designed to suit specific site requirements.

Controlling excessive torque

The new TorkDrive from Smith Flow Control is a device which prevents manual valves from being damaged due to excessive torque application during valve operation. It can be customised to suit most manufacturer’s handwheel operated valves (ball, gear, gate and globe) where valves require a torque monitoring of over 80Nm.

The device is set to a predetermined maximum torque and if, during the operation of the valve, the operating torque increases above the pre-set limit, the TorkDrive will slip, indicating an irregular valve condition. Following over-torque, the TorkDrive unit will automatically reset to the predetermined torque.

TorkDrive is a customisable add-on tool which minimises the risk associated with unavoidable plant/process shutdown and unnecessary repair costs through valve over-torque. It can be specified as a simple, standalone unit mounted on either the valve input handwheel or directly to the valve input shaft; or it can be used in conjunction with SFC’s EasiDrive portable valve actuator, a non-impacting, air-driven power tool designed to simplify valve operations.

In most circumstances, manual adjustment of the power source (air or electric) restricts or limits the output torque and speed (RPM) of the EasiDrive. However, if the use of the portable actuator is not restricted to larger valves and is used on a wide range of valves with differing sizes and operating torques, the TorkDrive would be the ideal solution. TorkDrive limits or restricts the operator from applying excessive force and protects the valve and valve seat from the over-torque that could be generated via the tool.

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