design and technology

• Induction generator-equipped turbines- for variable-flow incidental-power applications.

• Synchronous alternator-equipped turbines- for captive-power applications.

• Single-stage impulse turbines- for enthalpy drops of up to 200 kJ/kg.

• Two-stage velocity-compounded Curtis turbines- for enthalpy drops from 200 - 400 kJ/kg.

• Combinations of the above, in multiple-modules, with integral gearboxes- for larger than 400 kJ/kg enthalpy drops.

• Multi-module, Multi-stage back-pressure extraction/injection turbines.

• Multi-module, Multi-stage condensing-extraction/injection turbines.

• The effective utilization of advanced aerodynamic designs, high-grade aerospace material, technologies such as Brown Boveri thrust collar, Blisks and many other innovative and advanced techniques result in providing turbines that run at 12,000 rpm. (conventional runs at 3000 – 3600 rpm).

• This enables the use of small rotor disks (typically 300 — 330 mm in diameter), with large arcs of entry (30 — 100%) coupled with efficiency gains of 15-30% and highest reliability over conventional designs.

• Our 160 kW ECT turbine + gearbox weighs about 400 kgs against a low-speed conventional machine which weighs about 2,500 - 4,000 kg. This is possible only through the use of premium materials for construction, such as austenitic stainless-steel costing 2-3 times as much as cast iron or low-alloy steel, yet allowing competitive pricing.

• For several process-related reasons, a typical MSME process industry may suffer 2-3 times weekly turbine shutdown for extended periods. In addition, MSME's saturated steam boilers often generate wet steam which is acceptable for process heating applications.

• In such conditions, it is imperative that conventional cast iron and low-alloy steel construction would suffer significant corrosion and quickly deteriorate and erode as a result of high temperature, humidity, wetness and air infiltration.

• To address these concerns, TurboTech's ECT's corrosion/erosion life will be at least an order of magnitude greater than that of conventional turbines, owing to its high-speed design.

• We use an agile method of blading design and manufacture which is unique in the industry, especially in low-value small steam turbines. We combine the efficiency advantages of engineered turbomachinery with the short lead time, more common to "parts-bin" blading.

• The mach numbers, angle, and blade size are calculated using in-house proprietary software depending on the customer's steam specifications.

• The aerodynamic design of the blading is converted to manufacturing drawings digitally using high-efficiency tested blade profiles, and a CNC (computerised numerical control) machining program is directly generated in a paperless digital environment.

• The resultant CNC program is digitally transferred to the in-house 4-axis CNC milling machine, where the blades are automatically machined from a solid blank.  The blanks are generally prepared and stocked in order to save manufacturing lead-time.

• The high quality material chosen for our ECT turbine has adequate elongation and rubs against the casing before rupture. This technology is utilised in the aviation industry to ensure safety by preventing rotor bust in case of a control failure.

• This kind of safety is unique to TurboTech's ECT.

• In most circumstances, the accuracy of blade profiles is 20–30 microns. This is particularly good for comparing inserted blades which have tolerances of 200 — 300 microns. Moreover, the blisk is always fully bladed, unlike the inserted blade designs which often have "missing" blades due to the locking features. As a result, blisks offer the potential to fully exploit the advanced aerodynamic design methods employed in the ECT's design.

The integral gearbox; turbine rotor is custom-developed by TurboTech. It is separated from the turbine module by a steam and oil seal.

This offers the following benefits over a conventional separate gearbox:

• Elimination of high-speed coupling, along with its attendant balance and misalignment problems.

• Elimination of two turbine bearings, as the gearbox input shaft

• Bearings support the turbine rotor

• Elimination of one steam seal, as there is only one seal for the turbine module.

• Compact arrangement, with minimum footprint and weight. This is essential for incidental power applications in existing plants, where space is always a severe constraint.

The elimination of these critical parts enhance reliability and lowers the cost of the system as well.

• The ECT and the driven generator are fitted on a single rigid fabricated carbon-steel skid and contain the entire lubrication system. The unit is fully factory assembled, aligned and the coupling between gearbox and generator is installed.

• The skid is placed on rubber AVMs to eliminate the need for any civil works at the customer's site and make it easy and reaction-free to align with steam lines- truly "plug-and-play".

• The 160 kW ECTs is about 1,500 kg, which can be easily moved and maneuvered into place by a single man using a pallet trolley.

Know more about the complete system mechanism-

• On insertion of the key, and turning on the system, the control system conducts a safety and health check, and only then permits start.

• Any fault, if identified, is enunciated in simple English and it can be rectified easily.

• If the system is functioning properly, the user can turn the key to the spring-loaded "START" position for a brief period before releasing it, as if starting a car.

• The PLC then initiates the start sequence which includes pre-warming the turbine, gradual acceleration to synchronous speed, synchronisation, and commanding the breaker closed.

• In general, no dedicated turbine operator is required. The PLC based controls can be integrated with plant-wide DCS systems, which can be remotely monitored using the Internet.

• ECT is enabled with quick start-up of 10-30 minutes typically suited for CSP based application.

• ECT panels are provided with the various fault Monitoring and Protection system which are as follows:
  ■ Over speed / Over frequency
  ■ Under speed / Under frequency
  ■ Overload
  ■ Earth leakage trip
  ■ High Temperature trip of bearings and Lube oil.
  ■ High Temperature of Generator Winding
  ■ Low Lube Oil PressureLow air pressure to the control valve
  ■ Reverse Power relay with time delay
  ■ Emergency Trip
  

• In case of any fault the turbine is tripped immediately and audio-visual indications are turned on for operator’s attention. The HMI also indicates the type of fault that occurred.