Published on November 8, 2007
MTG “Multi-function Tank Gauge”: MTG “Multi-function Tank Gauge” Slide2: MTG™ Theory of Operation The MTG™ Multi-function Tank Gauge is based upon mass and temperature measurement. The MTG™ design eliminates problems with earlier mass technologies such as Bubblers, HTG (Hydrostatic Tank Gauge), and some other techniques utilizing nitrogen bubbles measured at multiple locations and multiplexed through one pressure transducer. These earlier technologies suffered problems due to the improper design of the product, not because they used mass based measurement. MTG™ (Multi-function Tank Gauge) overcomes the problems with both reference point movement and temperature change that affects level devices. Some level devices claim to be non-obtrusive, however, to do net volume a temperature device is required. The MTG™ has no moving parts and uses only one tank entry for all measurements. In addition to mass, the MTG™ provides accurate level and temperature measurement. The MTG™ Multi-function Tank Gauge is constructed of sensor, joint, and pipe sections assembled into a vertical probe assembly. The standard configuration includes up to six sensor units, consisting of both an accurate pressure and temperature sensor module located in each of the sensor units. The probe is assembled and lowered into the tank from the top. A double O-ring seal in the slip flange allows the probe to sit on the tank floor. As the tank expands or contracts from normal emptying and filling the MTG™ remains bottom referenced. Usually the sensor sections are spread evenly over the tank height. The first one is always located near the bottom and the last one is always in the vapor space of the tank. In some custom configurations the sensor location inside the liquid space may vary based upon the product or service application. Copyright© 2002 Gauging Systems Inc. MTG components Assembled MTG probe Installation kit Transmitter head Sensor assembly: MTG components Assembled MTG probe Installation kit Transmitter head Sensor assembly Copyright© 2002 Gauging Systems Inc. Slide4: The MTG™ probe is a rigid stainless steel construction with each sensor position precisely located. The differential value P1 – P6 (see figure 1 on page 2) can be presented as: P1 – P6=D*H*g (1) Where: D is the liquid density; H is the height of the liquid column above the first sensor; g is the local gravity constant. Therefore the mass of the liquid above the first pressure sensor can be calculated as follows: M=(P1 – P6)*S/g=D*H*S=D*V (2) Where S is the average cross-section area of the tank given by the tank strapping table; g is the gravity constant; V is the resulting volume of the liquid above the first pressure sensor: The pressure difference DP12= P1 - P2 gives the average density value D12 in the area between first and second sensors provided that the distance H12 between the corresponding pressure sensing points is precisely known: D12=( P1 - P2)/g/H12 (3) Copyright© 2002 Gauging Systems Inc. Slide5: The density layers between the rest of the sensors are calculated in the same way: D23=( P2 – P3)/g/H23 (4) D34=( P3 – P4)/g/H34 (5) D45=( P4 – P5)/g/H45 (6) The density values measured as per formulas 3 to 6 and temperature measurements taken in the same points along the tank height allow bulding a density distribution curve. The level of liquid L in the tank is calculated as follows: L= Hi + Pi/g/Di (7) Where Hi is the location of the last sensor unit covered with liquid; Pi is the pressure measurement taken from the last sensor unit covered with liquid; Di is the current density value. Copyright© 2002 Gauging Systems Inc. MTGMulti-functionTank Gauge : MTG Multi-function Tank Gauge Copyright© 2002 Gauging Systems Inc. MTG Provides:: MTG Provides: Accurate LEVEL measurement MULTIPLE SPOT TEMPERATURES MULTIPLE DENSITY STRATA FREE WATER measurement CONTENT OF WATER in product 2nd INTERFACE (Emulsion in crude) CONTENT OF WATER in 2nd Interface Copyright© 2002 Gauging Systems Inc. MTG Also Provides:: MTG Also Provides: Accurate MASS measurement Product VOLUME (by Level or Mass) MASS (Leak Detection) SENSITIVITY VAPOR PRESSURE VAPOR TEMPERATURE Level, Temperature, Density, Pressure, Movement, and Stratification ALARMS Copyright© 2002 Gauging Systems Inc. MTG provides uncommon expectations from a tank gauge: MTG provides uncommon expectations from a tank gauge A payback from a tank gauge system Accurate inventory measurement Quantitative Mass Volume and Level / Temperature Volume No temperature effect on Mass Volume Mass & Level Volume, provides us a gray area Hydrocarbon emission loss on inventory Qualitative Ability to define product quality (Real time) Specific gravity / density Monitor for product density stratification Alarm (Q.A. product quality) Electrical savings, when to mix.. Copyright© 2002 Gauging Systems Inc. MTG provides uncommon expectations from a tank gauge 2: MTG provides uncommon expectations from a tank gauge 2 Multi-point Temperature Accuracy (Class A, Platinum, Four wire RTD’s) Monitor for product temperature stratification Alarm (over cooking) Electrical savings, when to heat.. Water content in product Do not pay for water in products received Do not pay for the transportation of water on product shipped Crude Oil, do not pay royalties on water produced Utilization of tank assets Automation of water draw-off When to use demulsifiers in crude oil, Increasing through put (decreased settling time) Eliminates waiting on lab analysis to view product quality Copyright© 2002 Gauging Systems Inc. MTG provides uncommon expectations from a tank gauge 3: MTG provides uncommon expectations from a tank gauge 3 Safety Redundant sensors = redundant alarms Mass, Pressure, Level, Temperature, etc. from four to six sensors. Monitoring of Vapor pressure Tank structural damage prevention Over pressure, i.e., stuck pressure relief vent Under pressure or vacuum Regulation or monitoring of gas blanketing system Reporting of hydrocarbon emission to environmental agencies Internal loss inventory from emission analysis Leak detection by mass Certification pending on 0.9 GPH (Meets Tightness Testing) Tank tightness testing (Legislation is pending) Blocking in of each tank for 72 hour test per year Copyright© 2002 Gauging Systems Inc. MTG provides uncommon expectations from a tank gauge 4: MTG provides uncommon expectations from a tank gauge 4 Reduced cost of ownership Installation Installs in service (2 men, 2-4 hours on a 40 ft. tank) MTG is bottom referenced and is not affected by product turbulence MTG does not require a Stilling well or Standpipe Does not require Slotting of Stilling well for accuracy Does not require Calibration pins for accuracy Does not interfere with gauge sampling MTG requires a 3” or larger flange opening MTG is Obtrusive technology, as is all inventory tank gauges Radar gauges require two openings, i.e., one for radar and one for a Temperature average device (Obtrusive) Copyright© 2002 Gauging Systems Inc. MTG provides uncommon expectations from a tank gauge 5: MTG provides uncommon expectations from a tank gauge 5 Electrical / Conduit Connection to one instrument, MTG Only UL, CSA, CENELEC I.S. Approved, PTB approval pending 24Vdc or 12Vdc before I.S. barriers Radio / Solar from gauge is Optional MTG Instrument MTG is Self calibration Calibration is based upon product movement MTG is Self Diagnostic Diagnostics are provided on every poll of the MTG Individual sensors can be viewed in raw engineering units in the maintenance mode from the host or remotely The application does not stress or tax the technology used within the MTG (Pressure transducers & Four wire RTD’s) Copyright© 2002 Gauging Systems Inc. MTG provides uncommon expectations from a tank gauge 6: MTG provides uncommon expectations from a tank gauge 6 Reduced Maintenance New system topology (10BASE-FL Ethernet) Designed to reduce electrical surges or lightning Design based upon commercial standards Designed to increase throughput of data Designed to communicate with end devices Designed to allow for future expansion Field interface composed of commercial off the shelf hardware (Ethernet Fiber Hub) Instruments providing Self calibration and Self Diagnostics Remote support via modem or internet Copyright© 2002 Gauging Systems Inc. TankHardware: Tank Hardware Copyright© 2002 Gauging Systems Inc. 10BASE-FL Topology: 10BASE-FL Topology Copyright© 2002 Gauging Systems Inc. BlueField™(Patent Pending): BlueField™(Patent Pending) The major cost in any tank gauging or tank farm automation project is the field wiring. Normally two-thirds (2/3) of the cost is on wire, conduit, electrical fitting, etc. The upgrade of older technology in the field is often delayed because of the capital money needed to replace the communications infastructure. This means the benefits are also delayed and cost you money.. Bluefield™ is a Communications Topology designed to 1) Reduce the cost cabling vs. conventional hardwire, 2) Increase the data throughput speed and reliability using commercial standards, 3) Provide electrical isolation to all field hardware (against power surges and lightning), and 4) Provide two-way communications from Intranet based servers or application users (Tank Gauge Software) all the way to the MTG™ Multi-function Tank Gauge (or other field devices). The standards adapted for the Bluefield™ Topology are known by most MIS people and consist of the following: Win TG PRO™ Software based upon Microsoft™ Windows 2000 or XP Operating System and designed for .NET ready platform, Ethernet 10BASE-FL (Fiber Link) hubs and smart switches acting as the field interfaces, Commercial grade Fiber Optic cable run into the tank farm to the GSI E/TGI™ Enhanced Tank Gauge Interface (local display) or GSI E/RTU™ Enhanced Remote Terminal Unit (with Single or redundant TCP/IP addresses and 10BASE-FL connections). Communications to the MTG™ Multi-function Tank Gauge over Bluetooth™, i.e., Short distance (328 ft.), 2.4GHz radio communications (or hardwired). See GSI Product Bulletin 5150 on the Bluefield™ Topology. Limitations on the use of radio may apply, I.e., local testing of radio channels must be made with any frequency hopping radio’s on non licensed channels before serious consideration of the BlueTooth™ portion is made. The Ethernet 10BASE-FL backbone bus is still preferred with or without radio connectivity to the instrument. Copyright© 2002 Gauging Systems Inc. NEW BlueField™: BlueField™ Copyright© 2002 Gauging Systems Inc. Hard Wire Topology: Hard Wire Topology Copyright© 2002 Gauging Systems Inc. Thank you!: Thank you! Gauging Systems Inc. (GSI) 910 Industrial Blvd. Sugar Land, Texas 77478 Phone: 281-980-3999 Fax: 281-980-6929 E-mail: [email protected] Http://www.gaugingsystemsinc.com Http://www.tankgauging.info Under Construction Copyright© 2002 Gauging Systems Inc.