31 5000 9084 e 2004 11

DRAWING/DOCUMENT STATUS A FOR REFERENCE 2006-04-10 First issue Steenmeyer DATE DESCRIPTION Bearb Coord Rev Liedtke Sudhoff Geprüft Checked APPD PROJECT : CAMAU 750MW COMBINED CYCLE POWER PLANT OWNER : OWNER’S ENGINEER : PETRO VIETNAM CPMB CONTRACTOR : CONTRACTOR’S ENGINEER : LILAMA CORPORATION FICHTNER SUBCONTRACTOR’S NAME : SUBCONTRACTOR’S SUPPLIER : s DELMAS POWER GENERATION DRAWING TITLE : System Description Natural Gas PKZ UAS Contents Code Ursprung/Original Reg No UNID Urspr.-PKZ-Nr Orig.-PC Ursprung-Nr./Original-No Projekt/Project gezeich Drawn bearb Coord geprüft Checked Abtlg Dept PKZ/PC Datum Date Name 06-04-10 STEENM 06-04-10 LIEDTKE 06-04-10 SUDHOFF P415 sgd s AG POWER GENERATION CA MAU CCPP VIT154 Maßstab Scale UA/DCC Type Inhaltskennzeichen Contents Code N/A A4 Benennung/Title System Description Natural Gas Dienstst./Dept P415 XS00 MBP Zähl.-Nr Reg.-No Index/Rev UNID 423216828 355021 Version A Blatt-Nr./Page-No CM1-L1-M-MBP.08-355021 Erstellt mit/designed with of Ersatz für Supersedes Gas Turbine Description of Auxiliary Systems Fuel Supply System (Gaseous) Natural Gas System Refer also to: The reproduction, transmission or use of this document or its content is not permitted without express written authority Offenders will be liable for damages All rights, including rights created by patent grant or registration of a utility model or design, are reserved List of Control Settings (SREL) List of Measuring Instruments List of Electrical Loads Equipment List Requirements for GT Working Media Combustion Chamber Instrumentation P+I Diagram, Combustion Chamber P+I Diagram, Natural Gas Automatic Draining of the NG System P+I Diagram, Automatic Draining of the NG System Ignition Gas System P+I Diagram, Ignition Gas System Hydraulic Oil for Natural Gas Valves P+I Diagram, Hydraulic Oil for Natural Gas Valves Natural Gas Flow Measurement Natural gas consumption is measured by flowmeters installed upstream of the terminal point of supply These flowmeters are not part of the natural gas system and are therefore not described in this document 3.1-0210 3.1-0220 3.1-0230 3.1-0240 3.1-0260 3.1-3000 3.1-3010 3.1-5010 3.1-5300 Natural Gas Strainer Natural gas strainer MBP11AT001 is located at the upstream terminal point of supply Its task is to prevent the ingress of any coarse foreign matter which may be present in the piping between the fine filter unit and the strainer into the natural gas emergency stop valve In the event of trip, such foreign matter could impair proper closing of the emergency stop valve The fine filter system itself is part of the natural gas supply system and is not described here 3.1-5310 3.1-6000 3.1-6010 3.1-9200 3.1-9210 Settings, limits, and measuring ranges of the devices referred to here are given in the List of Measuring Instruments, Equipment List, and List of Control Settings (SREL) This description only gives guideline values Pilot Gas Flow Measurement A device is installed downstream of pilot gas control valve MBP23AA151 for measuring and recording pilot gas mass flow data Function The amount of pilot gas supplied has a major impact on the humming and vibration behavior of the gas turbine For this reason, pilot gas flow is measured with flowmeter MBP33CF101 during commissioning to precisely determine the amount of pilot gas supplied and for optimization of burner settings The natural gas system has two functions: on the one hand it controls the natural gas mass flow into the GT combustion chamber and on the other it shuts off the flow of natural gas to the gas turbine under certain conditions The flow of natural gas to the gas turbine is cut off by rapidly- and tightly-closing shutoff valves on shutdown, during outages, during fuel oil operation and in the event of postulated faults Vented Gas Seal Function The functions of the most important components of the natural gas system are described in the following subsections The vented gas seal in the natural gas system comprises natural gas emergency stop valve MBP13AA051, which constitutes the first shutoff element, and also natural gas diffusion control valve MBP21AA151, natural gas premix control valve MBP22AA151, and pilot gas control valve MBP23AA151, which collectively constitute the second shutoff element Pressure relief valve MBP13AA501 is located between the first and second shutoff elements Natural Gas Supply Class: RESTRICTED A natural gas supply system must be provided upstream of the natural gas system to ensure that this fuel is available in the quantity and quality required by operational demands The natural gas supply system is not described in this Section Dry, clean natural gas must be supplied to the natural gas system to prevent corrosion, erosion, and the formation of deposits on the system components Natural gas pressure at the system inlet must be relatively constant regardless of the rate at which it is supplied This pressure is dependent on the composition of the natural gas and is specified as setting P.GAS.01 in the List of Control Settings The vented gas seal reliably isolates the gas system when the latter is not active The vented gas seal comprises a tight-closing, dual-element shutoff device whose valves have a fail-safe closing energy These valves close automatically in the event of a loss of opening energy (for example, hydraulic pressure) This is achieved using a spring that is compressed by the opening energy and released when such force is no longer applied, actuating the valve to its CLOSED position Natural gas supply requirements are summarized in Section 3.1-0260 A pressure relief valve—located between the first and second shutoff elements—is open when these shutoff elements are closed This depressurizes the piping section between the shutoff elements Siemens AG Power Generation 3.1-5000-9084/1 MBP 1104E Gas Turbine Description of Auxiliary Systems Fuel Supply System (Gaseous) Natural Gas System natural gas supplied to the diffusion burners as stipulated by the gas turbine controller Requisite actuation of the diffusion control valve is performed hydraulically Section 3.1-9200, “Hydraulic Oil for Natural Gas Valves”, elucidates the function of the hydraulic actuator in detail In the event of a postulated valve seat leak in the natural gas emergency stop valve, pressure cannot build up upstream of the natural gas control valves as the associated gas leakage is routed via the relief line to a location which is not critical and released This reliably prevents unintentional flows of natural gas from entering the combustion chamber and also prevents air from the compressor outlet or combustion gases from ingressing into the natural gas supply network A bore is provided in the bottom of the natural gas diffusion system control valve for connection to the automatic draining system The functional principle of the automatic draining system is elucidated in description 3.15300 The pressure relief valve is closed when the GT is operated on natural gas The first shutoff element and, depending on the operating mode, one or more of the control valves that constitute the second shutoff element are open at this time Natural Gas Premix Control Valve (Second Shutoff Element) The natural gas premix control valve (NG PM CV) is actuated in accordance with the requirements of the gas turbine operating modes and regulates the natural gas mass flow to the premix burners In addition to its control function, the natural gas premix control valve is an element of the vented gas seal that also includes the diffusion and pilot gas control valves As the function of the premix control valve is equivalent to that of the diffusion control valve, please refer to subsection “Natural Gas Diffusion Control Valve” for details The reproduction, transmission or use of this document or its content is not permitted without express written authority Offenders will be liable for damages All rights, including rights created by patent grant or registration of a utility model or design, are reserved Natural Gas Pressure Relief Valve The natural gas pressure relief valve is part of the vented gas seal and permits depressurization of the piping sections between the first and second shutoff elements when the natural gas system is not active The vented gas seal is described in detail in the subsection “Vented Gas Seal Function” Natural Gas Emergency Stop Valve (First Shutoff Element) A bore is provided in the bottom of the natural gas premix system control valve for connection to the automatic draining system The functional principle of the automatic draining system is elucidated in description 3.1-5300 The natural gas emergency stop valve (NG ESV) is a rapid-closing, fail-safe, and leak-tight shutoff valve Its function is to enable or disenable the flow of natural gas to the burners on startup and shutdown of the gas turbine It is closed in the event of faults which require the immediate interruption of the supply of natural gas to the gas turbine The NG ESV is opened hydraulically and closed very rapidly by spring force (in less than one second) The hydraulic actuator mechanism is described in Section 3.1-9200, “Hydraulic Oil for Natural Gas Valves” Pilot Gas Control Valve (Second Shutoff Element) Like the natural gas diffusion and premix control valves, the pilot gas control valve (PG CV) is a leak-tight and failsafe shutoff valve which, in addition to controlling the mass flow of pilot gas, is also part of the vented gas seal The pilot flames are diffusion flames that are required in natural gas premix mode to stabilize the premix flames Class: RESTRICTED Natural Gas Diffusion Control Valve (Second Shutoff Element) The PG CV controls the flow of natural gas through the pilot gas burners The flow of pilot gas is set as a function of NOX emissions data, flame stability, and the humming and vibration behavior of the gas turbine Characteristics stored in the controller are used to stipulate the flow of pilot gas as appropriate to the operating mode The natural gas diffusion control valve (NG DM CV) is a leak-tight and fail-safe shutoff valve which, in addition to controlling the mass flow of natural gas, also functions as a shutoff element The NG DM CV, together with the premix and pilot gas control valves, constitutes the second shutoff element of the vented gas seal Fail-safe means that the valve in question closes automatically on loss of opening energy As with the emergency stop valve, this is achieved using a spring that is compressed when the valve is opened When the opening force is no longer applied, the compressed spring extends and closes the valve.The natural gas diffusion control valve modulates the flow of Like the natural gas diffusion control valve, the pilot gas control valve is hydraulically actuated Section 3.1-9200, “Hydraulic Oil for Natural Gas Valves”, elucidates the function of the hydraulic actuator in detail A bore is provided in the bottom of the pilot gas control valve for connection to the automatic draining system The functional principle of the automatic draining system is elucidated in description 3.1-5300 Siemens AG Power Generation 3.1-5000-9084/2 MBP 1104E The reproduction, transmission or use of this document or its content is not permitted without express written authority Offenders will be liable for damages All rights, including rights created by patent grant or registration of a utility model or design, are reserved Gas Turbine Description of Auxiliary Systems Fuel Supply System (Gaseous) Natural Gas System Gas Lines to the Natural Gas Burners Natural Gas Temperature Monitoring Downstream of the natural gas emergency stop valve the main natural gas supply line splits into the diffusion, premix, and pilot gas branches The control valves are located on the NG package a short distance downstream of this point Downstream of the natural gas package, each of the three separate gas supply lines empties into a corresponding ring line; branch lines lead from these ring lines to the individual burners In the standard configuration, the natural gas system is equipped with three resistance thermometers MBP13CT101, MBP13CT102, and MBP13CT103 located in the natural gas supply line upstream of the NG ESV If the gas turbine is operated with preheated natural gas, there is a danger that the natural gas temperature might exceed the permissible limit in the event of a fault in the preheating system An alarm is annunciated in the event that at least two of these three thermometers indicate that limit T.GAS.01 has been violated If a second, higher limit T.GAS.02 is exceeded, the natural gas system trips Natural gas temperature readings are used by the gas turbine controller to correct the lift setpoints for the diffusion, premix, and pilot gas control valve The optional connection for the ignition gas line (connection BI) is located directly downstream of the diffusion control valve The ignition gas system is not included in this description (cf 3.1-6000, “Ignition Gas System” for details).During operation in NG premix mode or on FO, minor localized pressure differences in the combustion chamber cause cross flows of air from the compressor outlet through the natural gas burners, the associated branch lines and the natural gas ring lines to the burners In the process, the small flow of air from the compressor outlet cools down Depending on the ambient and site conditions, this may involve temperatures below the dew point and thus accumulation of condensation in the branch line and in the natural gas connecting lines up to the respective NG control valve The amount of condensation that forms can be so large as to impair availability when the NG burners are reactivated after an extended period of operation in NG PM or on fuel oil Natural Gas Pressure Monitoring The amount of natural gas that burns in the gas turbine combustion chamber is a function of the supply pressure of the gas, the lift of the natural gas control valves, and the combustion chamber pressure Natural gas pressure is measured upstream of the natural gas emergency stop valve by pressure transducers MBP13CP101 and MBP13CP102, and downstream of the natural gas emergency stop valve by pressure transducer MBP14CP101.To ensure reliable operation of the gas turbine in all operating modes (diffusion and premix), the natural gas pressure is checked for violation of prescribed maximum and minimum limits Actions appropriate to the respective operating mode are initiated if these limits are violated: Small amounts of ignition gas (propane, butane) that accumulate after a fuel oil start or accumulation of FO after operation on FO, also in connection with possible condensation that collects in the NG DM line, may cause damage to the supply piping when the NG burners are activated All Operating Modes The condensation (of ignition gas and fuel oil constituents) that accumulates is drained from the lowest points of the connecting pipes to the automatic draining system via lines that are laid with a negative slope The functional principle of the automatic draining system is elucidated in description 3.1-5300.In addition, some of the branch lines from the ring line to the diffusion burners are also heated − If the natural gas pressure (MBP14CP101) downstream of the natural gas emergency stop valve exceeds limit P.GAS.11, the pretrip alarm “NG PRESSURE DOWNSTREAM OF NG ESV TOO HIGH >MAX” is annunciated Natural Gas Diffusion Mode (NG DM) If the natural gas pressure measured by MBP13CP101/102 declines below limit P.GAS.06 and that measured by MBP14CP101 below P.GAS.06 minus 0.5bar (pressure drop across NG ESV) when natural gas is being supplied, the pretrip alarm “NG PRESSURE LOW