Equipment Roundup

Predicting pressure pulsation

Rovsing Dynamics has launched a new, cost-effective method to detect combustion pressure pulsation in gas turbines. This new feature of the OPENpredictor monitoring system helps prevent fatigue, damage and unplanned shutdowns of power plants.

Pressure pulsation is a critical phenomenon which can occur in gas turbines e.g. with low NOx burners, where turbulent combustion may excite the acoustical modes in the combustor transition part and turbine cavities. If undetected, pressure pulsation can lead to excessive dynamic loading of combustor liners and power turbine blades, and result in efficiency loss as well as fatigue and failure of critical gas turbine components.

OPENpredictor provides precise, online measuring of pulsations in the gas turbine’s combustion chamber. The practical system to monitor combustion pressure pulsation is easily installed and can be retrofitted. Whereas traditional pressure sensors typically are mounted inside the combustion chamber, the OPENpredictor uses accelerometers mounted on the outside of the combustor. The system’s advanced signal processing method is very precise and helps avoid unplanned, unjustified shutdowns. All in all, the system increases reliability of operations and allows power plant operators to move from ‘trial and error’ to a more precise and objective assessment of pressure pulsations in order to reach the optimum balance of the combustion process.

Pressure pulsation can lead to fatigue and loss of efficiency
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The unique feature of the automated detection, warning and diagnosis enables process operators to change fuel flow and load conditions to avoid excessive pressure pulsation, leading to potential damage. Instant warnings are issued when pulsations exceed acceptable levels, accompanied by diagnostic information to help identify the pulsation cause.

OPENpredictor can be expanded to also monitor the exhaust temperature distribution of a gas turbine. The purpose is to identify temperature deviations e.g. from blocked nozzles, potentially leading to blade fatigue, combustor deformation and shutdown.

Monitoring of combustion pressure pulsation and temperature distribution are just some of the many features of the OPENpredictor system. Other modules provide monitoring of the condition, performance and reliability of a wide variety of critical rotating and reciprocating machinery.

Thumbs up down under

Yokogawa Australia Pty. Ltd. has received a contract for a control systems replacement project at the Loy Yang A power station in Australia. The contract is estimated to be worth A$30 million ($22.2 million).

The 2200 MW Loy Yang A coal fired power station is the largest thermal power station in Victoria and went into operation in 1984. To address the long-term stability of station operation, Yokogawa will replace the control systems for the whole station, including the power generation, station common plant and coal transportation facilities, between October 2007 and June 2014.

Yokogawa will provide Loy Yang Power with an integrated production control system, a network-based control system, a safety instrumented system, a plant information management system, and other package software, plus engineering for these systems.

Allen gears up

UK-based gearbox specialist Allen Gears is to strengthen its position in the power generation sector by extending its epicyclic product range into the 20-40 MW range.

Allen Gears has demonstrated the benefits of epicyclic gearboxes in more than 3000 units it has supplied for the 3-20 MW powergen range since the early 1980s. In this highly competitive sector, small differences in packaging efficiency, operational reliability and physical size are key factors influencing prospective customers’ decision, clearly favouring epicyclic gearboxes over parallel-shaft designs for power generation use.

Allen gears has demonstrated the benefits of epicyclic gearboxes in power generation applications
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“Our research has shown that epicyclic designs for today’s power generation market will provide distinct and measurable customer advantages in terms of cost, weight and physical size over the alternative parallel shaft solution,” says Neil Whittaker managing director of Allen Gears.

High steel prices alone can mean lower capital cost and greater price stability for the lighter epicyclic option, adds Whittaker. For example, a 37 MW epicyclic gearbox for an RB211 gas turbine genset weighs just 70 per cent of the mass of an equivalent parallel shaft unit. Such a unit would also have a 14 per cent cost advantage over a parallel shaft unit, as well as being smaller in size.

Solar batteries offer optimum performance

Alcad’s new solar range of rechargeable nickel-cadmium (Ni-Cd) batteries has been developed to deliver totally reliable service and low maintenance for renewable energy installations. They provide the ideal, cost-effective alternative to valve regulated lead acidic (VRLA) batteries in demanding applications.

Alcad Solar batteries are designed to continue to operate at any state of charge, and reach a high state of charge without boost or reconditioning charges. They are compatible with all current PV charge regulators and conventional industrial battery chargers.

Alcad’s new Solar battery is designed to provide reliable service with low maintenance needs in renewable energy applications
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A robust pocket plate construction and stable electrochemistry enables Alcad Solar units to operate comfortably within a temperature range of -20à‚°C to +50à‚°C, and they can tolerate extremes of -50à‚°C to +70à‚°C. They are designed to be low maintenance and to provide a reliable and predictable performance over a 20-year service lifetime.

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