Turbomachinery for Nitric Acid Plants - MAN Diesel & Turbo

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Control and safety equipment A complex machine train of the kind used in a nitric acid plant makes very great demands on the control and protection systems in terms of quality and flexibility. Such systems must consider the requirements of the process and provide all functions from start-up to emergency shutdown of the machine train and process. MAN Turbo has developed electronic control and protection systems which interface with the mechanically/hydraulically actuated final control elements. Anti-surge control, surge detector In the performance graph of a turbo compressor the surge line is the dividing line between ranges of stable and un-stable operation. Reduction of the volume flow rate beyond this line causes separation of the flow from the blading, the gas flows periodically from the discharge end to the suction end – a phenomenon referred to as compressor surging. The resultant extreme load reversals and temperature fluctuations in the gas-handling components of the machine must be avoided. This is a task of the anti-surge control, a system which, by controlled opening of the blow-off or by-pass valves, always keeps the compressor flow rate in the stable range of the performance graph. A special development of MAN Turbo for this purpose is the electronic control and protection system called “Turbolog S7-400”. 16 Speed control To allow speed and therefore process pressures and flow rates – to be controlled as well as the machine train to be protected against overspeed, MAN Turbo has developed the turbine control and protection system “Turbolog S7- 400”. This system by far surpasses the requirements of NEMA specification SM 23, class D. Depending upon specific requirements, it is designed for any of the following functions: (Refer also to the special brochure “Turbolog S7- 400”.) redundant turbine speed control redundant overspeed protection complete functional testing of all trip circuits during normal operation speed-controlled starting of the turbine from standstill combined control of speed and extraction pressures back-pressure control control of turbines with sidestream admission inlet pressure control power output control frequency control
1 Trip valve with steam strainer 2 Live-steam control valves 3 Contral oil pressure accumulator 4 Speed controller with positioner (Turbolog) 5 Sealing-steam control 6 Shaft barring gear 7 By-pass valve 8 Surge detector 9 Non-return flap with closing device 10 Water injection 11 Blow-off valve 12 Anti-surge control 13 Surge detector 14 Non-return flap with closing device 15 Labyrinth sealing air for NO-gas compressor and tail gas expander 16 Labyrinth sealing air for bearing pedestals 17 Quick-closing inlet flap 18 Quick-opening by-pass flap 19 Adjustable stator blades 20 Axial-displacement measurement 21 Bearing-temperature measurement 22 Shaft-vibration measurement 23 Speed monitoring Quick shutdown Quick opening of blowoff valve Control of shaft barring gear 17
Page 1 and 2: Turbomachinery for Nitric Acid Plan
Page 4 and 5: Processes For the production of nit
Page 6 and 7: Axial compressor for air The first
Page 8 and 9: Centrifugal compressor for air For
Page 10 and 11: Nitrous gas compressor For the two-
Page 12 and 13: Tail gas expander Utilization of th
Page 14 and 15: Steam turbine for a 1,230-t/day two
Page 18 and 19: Components Baseframe/steel foundati
Page 20 and 21: Workshops To meet today’s demands
Page 22 and 23: Test facility MAN Turbo owns and op
Page 24: MAN Turbo AG Steinbrinkstrasse 1 46

Turbomachinery for Nitric Acid Plants - MAN Diesel & Turbo

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