Scribd
Upload
123 views3 pages

Coriolis Meter

Uploaded by

pkannan
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF or read online on Scribd
123 views3 pages

Coriolis Meter

Uploaded by

pkannan
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF or read online on Scribd
You are on page 1/ 3
Coriolis Mass Flow Meters For Bulk Measurement By Andre Verdone, KROHNE, Inc. courate measurement of liquids is important foe alle and gas industry predtion or consumption sites. This is especially true for bulk transfer ‘devices where lage volumes of products are being moved and must be monitored, includ ing crude oil pipelines, depos, gasoline and jet fuel tank farms, refineries and even cruise Tine terminals nthe past, mass transfer was measured in buches with weigh seals or load eels. However inallaton, calibration, and maintenance activi> ties ofa seae o load el are costly, dificult 0 do, ime consuming, and dot work for contins- fs processes. For tise processes, such me fds 28 orifice plates and magnetic low tubes fan measure volumetic low, but additional instruments are needed to measure temperate fnd pressure fo compensate for fd: density ‘changes. Inzoducingaditiona instrumentals Inoduces errors, which can result in an overall, ‘measurement enor rte a high as 3%. ‘Now, several measurement standards are roving toward use of Coriolis mass flow meters, which can measure mass flow directly, at the Same time as they measure temperature tnd density. Whats more, tansfer measure- rent by mass isthe most accurate method, sine mass is independent of, and unaffected by, changing process fluid characteristics, including. pressure, temperature, viscosity, conductivity, and gravity ‘Among the Coriolis devices available, the saght tbe design i being hailed as the mest accurate and easiest to install and. maintain. Especial for measurement skids, widely wed in the ol and as industy, the staght ube Coils meter can be a factor in minimizing kid ize ‘The Coriolis Effect What is the effect and why does it help with bulk measurement? In physics, the Coriolis effect is a deflection of moving ‘objects when they are viewed in a rotating Teference frame, In a reference frame with clockwise rotation, the deflection is Yo the left of the motion of the object. In a reference frame with counter-clockwise rotation, the deflection is tothe right. The mathematical ‘expression for the Coriolis Taree appeared in an 1835 paper by the French scientist Gaspard Gustave Coriolis, in connection with the theory of water wheels. Figure 1 provides a simple overview of a Coriolis measuring system, which makes use of the effect by using a symmetrical design ovatenyon or Figure 1: consisting of one or two measuring tubes, bither straight or curved. >A driver sets the measuring tube (AB) into a uniform funda- ‘menial oscillation mode. ‘When the flow velocity (v) equals O meters! second feetisecond (Oms0f), the Coriolis farce (Fe) is also 0, At flowing conditions, wine the flow velocity (¥) > 0 m/s0 fs, the ‘uid particles inthe product are accelerated ‘between points AC and decelerated between points CB, Tho Coriolis force (Fe) is generated by the inertia oF the fluid particles accelerated ‘twoen points AC and of those decelerted ‘between points CB, This force causes an extremely slight dis- tortion of the measuring tube that is super- imposed on the fundamental component snd is directly proportional tothe mass flow rat. ‘This distortion is picked up by special sensors. Since the oscillatory characteristics of the ‘measuring tube are dependent on temperature, the temperature is measured continuously and the measured values corrected accordingly na dualsube Coriolis meter, a manifold splits the flow through each ofthe two tubes, ‘The fall low always goes through the sensor ‘The two vibrating tubes rotate around the (wo fixed end points, creating a Coriolis effect when mass flows through, ‘Mechanical Meters “Measurement of petoleum fluids has been around for hundreds of years and has been per- Formed fairly reliably with the use of a wide sange of mechanical meters, ‘One significant drawback to mechanical meters is that hey experience serious wear and er, rd ‘an be plagued by high maintenance cass andthe eed fo lequent replacement pars Mechanical meters have 10 be calibrated ‘ona single grade, making recalibration, also Jnown a5 meter proving, necessary each time different product is measured. For example, 80 Pipetine & Gas journal {July 2012 / werw.pgiotine.com suppose a facility is handling cre oil from Venezuela one day and ffom Texas on another day. Since these have a different fuid bas the meter would have t0 be re-proved since the meters calibration factor is affected by 3 ‘arety of Muid conditions, especially density. Custody system operators often need (0 use 8 prover for measuring one batch to another, reproving for every different uid transaction "AL ofthis comes witha time and money. cost, Usually the facility operator outsources these activities, which adds othe cost of ran hing the facility. ‘Advances in manufacturing technology have led the receat ability to make Coriolis meters in lamer sizes, making them viable for oil and 1s applications that have heretofore been the domain of mechanical meters. Coriolis meters have no moving parts, so they have fewer parts to maintain. Also, unlike mechanical meter measurements that are used fr custody transfer ‘which have to be corrected using pressure and temperature compensation, the Coriolis meter ressures product mass drety independent of pressure and temperate Direct mass flow measurement with Coriolis. sass flow meters means that one flow meter witha single point of measurement can obtain ‘multiple measured values, ineluding mass flow and mass total, density and concentration, vo ‘ume flow and volume toa, and temperature It Figure 2: also reduces overal costs because theres only ‘Single instrument to buy and maintain, cables and power consumption are reduced, and com ‘wos are simplified. Figure 2 shows a rophic portrayal of a system that could be used for ‘volumetric ow measurement Reduced Pressure Drop Reduction in pressure drop is ne ofthe impor tant diflerentiating factors berwoon mechanical meters and Cerois mass flow meters. Pushing Mids pasta mechanical meter always creates 1 pressure drop which 8 ot recoverable. Every time one imposes a pressure drop, it must be st nominally five right tank, or tll he operator if he Dreet i nary mores hftr or cooler than expected. More DEY toe is ibility allows operators to maintain her cued dif congo, which utimately lads Tess waste minimal as com= fared to devices Ontario Re pared io devcee__Atone petroleum refinery site in Ona canada that produces refined gasoline, jet fuel sar other petroleum products, the operators Figure: Coril metall ship and meer proguct through aan, 6-inch ‘overcome withthe use of pump and maitsn, Expeilly for measurement pipeline that comes, ‘Canadian eae i meme, hese willbe skids that may Dae 10 Sacly pipeline, which in turn delivers the product reco op aon ec Inost_ small forint, Te, OSI tothe Greater Toronto area. They needed 49 no et pee tubes andthe only presse meter akes uP he maes Me rcnle measure the product leaving the plant site and mass ating fw ino ew roots piping, THe Sa seria the product going tthe shipping pipeline 9d dro te te meter. Usng te apt pipe consierbly, Sc igh ey the bent wanted a density reading atthe same time The pie sie ee eas he permanent ube version, Shisha vecoaitetinery ships diferent products trough one fresucedrop dan de bout ube ares: tube eine, and muck simpler tan ge and hao confi int Shey WS shipe rete op pet important benefit equalent mechanic! Nthveh would ping the correct prod. a Ti te ue ofthe Cols meter The alo rogue est ee ce Gpotream. "The pipeline was large the available 123! gained wil erates wing mechanical Figure 3 shows how te mele er TD Erinlo estate in the existing location was limited, ast majority ote runnng separate presse th easement seetncy did not want to do a large-scale foe mes Ses, ay the mechanical A ial beetle contols, modification to install additional structural and temper em ysne acercy err, which provide more Denso AS, of Sow rome aso poses 20.5% aceucy operational oormars (Operators can view she prs mee ee mcerauter everthing Sats OHMS the uid a rrr, and he Pere combed ina flow including volumes AP To flow, den- When tose va or ihe overall caused ty, and tempera, Ns for omer eS oe igher Pus, since mile ort, nea onverters or re ots over te indepen- thatallow for ect MCD to ace all the cach meee oul be fre degraded parameters The controls an ensire Sey ethane Te consiamenrs hat he comes PO 2 through tbe eo eat aking mete, make se pred! denn SO the Figur "2000 Carllis meter. MIDWESTERN CONTRACTORS | | FY

You might also like