Rosemount 5900C Radar Level Gauge for Bulk Liquid Tanks

Overview

The Rosemount 5900C is a non-contact radar level gauge that Emerson positions for reliable level monitoring of bulk liquids in storage tanks. Where its sister model targets fiscal custody transfer, the Rosemount 5900C is aimed at operational tank gauging: inventory overview, transfer monitoring and alarm handling at a lower cost per tank. Emerson lists an instrument accuracy of 1 mm for the parabolic, still-pipe array and LPG/LNG antennas, certified IEC 61508 SIL 2 capability, bus-powered two-wire installation, full functionality with wired or wireless communication, and installation on non-pressurised tanks without taking them out of service.

Seven Star LLC supplies the Rosemount 5900C to oil and gas operators, fuel depots, power stations, utilities and industrial plants in Oman and the GCC, from our office in Muscat. Typical buyers are operators who need accurate, low-maintenance radar on intermediate and working tanks, day tanks and process storage, but who do not require legal-metrology approval on every vessel.

Working Principle

Emerson explains that the Rosemount 5900C uses the FMCW (Frequency Modulated Continuous Wave) method with a linear frequency sweep around 10 GHz. The echo from the liquid surface comes back with a frequency that differs slightly from the frequency being transmitted at that instant. That frequency difference is directly proportional to the distance from the antenna to the surface, so the gauge can calculate level and ullage with high stability. The data sheet gives an update time of 0.3 s, a repeatability of 0.2 mm and a maximum level rate of up to 200 mm/s.

From a general engineering perspective, a radar gauge mounted on the tank roof removes the mechanical maintenance associated with servo gauges and float-and-tape systems. There are no wires, tapes or floats in the product, nothing to corrode or jam in heavy fuel oil or bitumen, and the gauge does not need recalibration. Because measurement is made through the vapour space, product density, viscosity and temperature changes do not shift the reading. For a tank farm manager, this means the Rosemount 5900C can run for years between interventions, while level, ullage, level rate and signal strength remain available to the control room through the tank hub.

Engineering Design of the Rosemount 5900C

The Rosemount 5900C uses one transmitter head for all antenna types, with a dual-compartment housing that separates electronics from cabling and can be replaced without opening the tank. The head is protected against lightning, moisture and rain and has surface protection against sulphur and salt-spray atmospheres, which matters at coastal terminals. Antenna options are parabolic for fixed-roof tanks and manhole covers, cone for fixed-roof tanks with smaller nozzles, still-pipe array for floating-roof tanks with still-pipes, LPG/LNG for gas storage, and 1 inch or 2 inch still-pipe antennas. The parabolic version also measures heavy fuel oil, bitumen and asphalt.

Power and communication use the two-wire FOUNDATION Fieldbus FISCO Tankbus from a Rosemount 2410 Tank Hub, with a FISCO supply of 9.0 to 17.5 VDC, polarity insensitive, and a bus current of 50 mA. The housing is rated IP 66/67 and NEMA 4X, and the gauge operates in ambient temperatures from -40 to +70 °C. The head weighs 5.1 kg, and complete gauges weigh about 12 kg with the cone antenna and 17 kg with the parabolic antenna.

Key Features

The Rosemount 5900C data sheet lists these strengths.

• Non-contact radar gives high reliability for continuous monitoring of bulk liquids.
• Instrument accuracy of 1 mm with parabolic, still-pipe array and LPG/LNG antennas, and 2 mm with cone and small still-pipe antennas.
• Certified IEC 61508 SIL 2 capability supports overfill alarm functions.
• Bus-powered two-wire installation on the intrinsically safe Tankbus keeps wiring simple and safe.
• Full functionality is available over wired or wireless communication.
• Non-pressurised tanks do not need to be taken out of service during installation.
• Drip-off antenna designs minimise condensation and keep the signal strong.
• A common transmitter head for all antennas reduces spare parts and simplifies maintenance.

Industrial Applications

Practical duties for the Rosemount 5900C in Oman include working and intermediate tanks at refineries, diesel and fuel oil storage at power and desalination plants, product tanks at inland fuel depots, slop and recovered oil tanks, and process storage at petrochemical and chemical plants in Sohar, Sur and Duqm. With a cone antenna it suits smaller fixed-roof tanks; with a still-pipe array antenna it suits floating-roof tanks; and with the LPG/LNG antenna it covers gas storage that needs reliable operational level data. Because non-pressurised tanks can stay in service during installation, upgrade projects at busy depots can replace old float gauges tank by tank without interrupting product receipts and dispatch.

Seven Star LLC supplies the Rosemount 5900C throughout the Sultanate of Oman and the GCC and can combine it with other Rosemount measurements on the same tanks, for example the Rosemount 5408 non-contacting radar level transmitter for process vessels, the Rosemount 3144P temperature transmitter for tank temperature, and the Rosemount 2120 vibrating fork level switch as an independent high-level alarm.

Technical Specifications

The following Rosemount 5900C data comes from Emerson product data sheet 00813-0100-5901.

How to Order

For a Rosemount 5900C offer, send Seven Star LLC your RFQ with the tank type, roof design, nozzle or still-pipe details, stored product and SIL requirement. The Emerson product data sheet is available from this page for engineering review. Seven Star LLC supplies Rosemount tank gauging instruments from Muscat to sites across Oman and the GCC, with sourcing and model selection support for installation and start-up.