The Importance of Understanding Thermophysical Properties Data and. Dr Norman Glen Consultant 2 September 2014

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1 The Importance of Understanding Thermophysical Properties Data and Effects on Engineering Calculations Dr Norman Glen Consultant 2 September 2014

2 Contents Introduction: Why is measurement important? The UK National Measurement Office (NMO) and the National Measurement System (NMS) Main presentation: What is thermodynamics Thermophysical property data Thermophysical property software Thermophysical property data effects on engineering calculations cu at Any questions?

3 Why is measurement important? Measurement plays a fundamental part in the innovation process. To develop new products and processes, companies need to measure quantity, quality and performance. To trade successfully, companies utilise a regulatory framework, based upon measurement confidence, ensuring access to global markets that are fair and open and without unnecessary barriers to trade. National Measurement Office (NMO)

4 Main Presentation: The Importance of Understanding Thermophysical Properties Data and Effects on Engineering Calculations

5 What is Thermodynamics?

6 What Is Thermodynamics 1? Mechanics Electro-mechanics Thermodynamics

7 What Is Thermodynamics 2? There are four laws. The third of them, the Second Law, was recognised first; the first, the Zeroth Law, was formulated last; the First Law was second; the Third Law might not even be a law in the same sense as the others! A crisp summation by P. W. Atkins P. W. Atkins: Professor at University of Oxford and writer of undergraduate text books.

8 What Is Thermodynamics 3? In the briefest terms, the second law states that a little energy is always wasted. You can t have a perpetual motion device because no matter how efficient, it will always lose energy and run down. The first law says that you can t create energy and the third that you can t reduce temperatures to absolute zero; there will always be some residual warmth. Bill Bryson: From his book A Short History of Nearly Everything Abi brief statement t t by Bill Bryson

9 What Is Thermodynamics 4? 1. You can never win, only break even 2. You can only break even e at absolute zero 3. You can never reach absolute zero

10 Component and Phase Phases Phase boundary Components vapour phase liquid phase ethanol water,

11 Thermophysical Property Data

12 The Anatomy of Property Data Data Numerical value Metadata Unit assignment Expected uncertainty Associated variables e.g. Temperature and Pressure Property relationships Parameterisation

13 The Data Cycle Data Requirements Measure or predict? Prediction Got any Data on this stuff? Software Tools User Project Definition Measurement Analysis Results

14 The Measurement Task Over 10 million chemicals indexed in Chemical Abstracts 20,000 chemicals in the European customs directory ~2000 chemicals in simulation software packages Hundreds of man-years have been expended already to measure the data for pure water These figures refer to pure components not mixtures

15 What Data Do You Need? Constant (T & P independent) Variable (T & P dependent) Phase equilibria

16 What Data Do You Need? SECTOR TECHNOLOGY KEY PROPERTIES STATE OF MEASUREMENT STATE OF MODELLING RANGE OF SYSTEMS OIL & GAS Traditional oil and gas recovery G, ρ, ρ H, P sat, C P, η, η λ Fair Good Limited HT/HP oil reservoir extraction (1500 bar, 200 o C) as above plus VLLE / solubility data (waxing) Poor Poor CHEMICALS & Distillation - continuous VLE, G, ρ, P sat Fair Good Very wide PETRO- CHEMICALS Distillation - batch as above Patchy Variable Separation LLE, G, ρ Patchy Good Reaction ΔH f Good Good Equipment design / operation -heat ρ, H, P sat, C P, η, λ Patchy Fair mass transfer D Patchy Fair Environmental impact VLE Patchy Fair PAPER & PRINTING As for chemicals Patchy Variable Limited FOOD & DRINK As for chemicals plus η - non-newtonian Poor Poor Very wide supercritical extraction P sat, solid-equilibria Patchy Good IRON & STEEL Casting solid equilibria, Patchy Variable Wide TEXTILES & FABRICS Dyeing Solubility, LLE, G, Patchy Variable Wide

17 Pure Substances - Generic Phase Diagram P c Melting / freezing curve Critical Point Pr ressur re P b Solid region Triple point Liquid region Vapour pressure curve Normal boiling point P t Vapour region T t T b Temperature T c

18 Pure Substances - H 2 0 Phase Diagram

19 Pure Substances - H 2 0 Phase Diagram Pressu ure (bar) 8000 Ice-VI Ice-V Ice -I Ice -II Ice-III Melting point Liquid (water) Boiling point Critical point Vapour (steam) Triple point Temperature (K)

20 Mixtures Thermodynamic Calculations The kind of thermodynamic calculations that often need to be solved are:- Return pure component constants (T c, P c, ω) Produce a table of properties (e.g. P sat, ρ, H) Determine phase equilibrium conditions Vapour, Liquid, Vapour/Liquid, Liquid/Liquid, Vapour/Liquid/Liquid,... Produce binary diagrams (T-x, P-x, y-x) Determine phase envelope (P-T)

21 Mixtures - Fundamental Calculation Quality Composition Stability How much of phase α is there? What are the compositions of the components present in phase α?? Is phase α a stable phase?

22 Mixtures: Volatile Liquids - Distillation

23 Mixtures: Volatile Liquids - Distillation P = constant rature Tempe Vapour T 2 a a 2 2 L+V T 1 a 1 a 3 T 3 Liquid a 3 a 4 0 Composition x 1 A

24 Flash Calculations Vapour - {y i } T, P, {z i } Feed P, T Flash Vapour Fraction α α = 0 : Bubble point α = 1 : Dew point α = a : Fixed fraction Liquid - {x i } Liquid Fraction (1- α)

25 Flash Calculations Exhaust T 2, P S = constant 80 Inlet Pressu ure / bar T 1, P 1 Isentropic compression Stream Composition Name Qty Methane 0.6 mol Ethane 0.35 mol Hexane 0.05 mol Temperature / C Feed Isentropic (P) flash at outlet pressure = 20 bar p = bar T = 20 C p 2 = 20bar T2 = C

26 Flash Calculations 1000 H = constant T 1, P 1 T 2, P Pressur re / bar 10 Solid Liquid Supercritical fluid Inlet Throttle Exhaust 1 Gas Temperature / o C Feed Isenthalpic (P) flash at outlet pressure = 1 bar p p 1 2 = 30bar = 1bar T T 1 2 = 20 C = 19.4 C

27 Thermophysical Property Software

28 Thermophysical Property Software Basic Database of fluid properties at fixed conditions e.g. DETHERM Intermediate Database and interpolation routines for pure compounds Advanced e.g. DIPPR801 database and DIADEM interface Database(s), calculation and estimation methods for pure compounds and mixtures e.g. PPDS

29 PPDS What is it? CALCULATION PACKAGE FOR THERMOPHYSICAL PROPERTIES OF FLUIDS AND FLUID MIXTURES Database of ~1500 chemicals 18 constant, 14 variable properties p 36 thermodynamic model sets 37 types of flash calculation Supports multiple user databanks including DIPPR-801 Special packages for: Water (IAPS-84 and IAPWS-95), Petroleum Fractions, Refrigerants IUPAC high-accuracy Equation of State Selected aqueous electrolyte solutions AGA 8

30 PPDS Client Interface Example 1 Text and graphical outputs are available

31 PPDS Client Interface Example - 2 Calculation of the envelope showing the special points

32 PPDS Client Interface - AGA8 Package PPDS now has a full PPDS now has a full implementation of the AGA8-DC92 method

33 PPDS Client Interface - Petroleum Fractions Package The Petroleum Fractions package allows complex mixtures to be defined as pseudo-components, then used with other components from the PPDS banks

34 PPDS Excel Interface Example

35 PPDS Excel Interface Example Change numbers on the sheet and PPDS recalculates instantly

36 Thermophysical Property Data Effects Thermophysical Property Data Effects on Engineering Calculations

37 Density Interchange between mass and volume Describes mass of fluid Therefore momentum Interaction with meters Defines gravity separation Low density will float on top of high density fluids Separation ρ = Stratification M V M V

decreases with temperature Viscosity of gases increases with

38 Viscosity Expression of how thick the fluid is. Internal friction, resistance to shear Viscosity of liquids decreases with temperature Viscosity of gases increases with temperaturet Commonly perceived as thickness or yp resistance to flow (measure of fluid friction)

39 Typical Viscosities Substance Approximate Viscosity at 20 C (cp) Ambient Air 0.02 Water Engine Oil 100 Gear Oil 1,000 Honey 10,000000

40 Density & Viscosity Interact in Flow Density momentum keeping going Viscosity friction stopping Interaction studied by Osborne Reynolds in 1883 Re Momentum viscosity

41 Reynolds Number (Re) Dynamic forces Re = ρ v μ d Laminar Flow Viscous forces The magnitude of Re determines whether dynamic or viscous forces dominate Turbulent Flow

42 Reynolds Number (Re) Laminar Flow Transition Flow Re < < Re < 4000 Viscous forces dominate Switches back and forth Turbulent Flow Re > 4000 Inertial forces dominate Most industrial flows are turbulent

43 Density Errors Calculated using 'Accurate' method Density / kgm Calculated using 'Consistent' method Temperature / C

44 Density Errors Calculated using 'Accurate' method Density / kgm Calculated using 'Consistent' method Temperature / C

45 Viscosity Errors

46 Effect on K-Factor ulses per li tre K-Factor / P 'Correct' fluid propoerty data 'Incorrect' fluid property data Reynolds Number / -

47 Conclusions Accurate thermophysical property p data are vital for many applications Need to understand effects of temperature, pressure and composition on fluid properties Need confidence in fluid property data (measured or estimated values) Software can help but need to know its capabilities and limitations

48 For a free 30-day trial of PPDS, please contact us -

49 Thank you for listening Any questions?

50 NEL Contact Tel: + 44 (0) NEL Contacts Audit & Allocation Alick MacGillivray amacgillivray@tuvnel.com CFD Neil Bowman nbowman@tuvnel.com Densitometers Norman Glen nglen@tuvnel.com Erosion John Peters jpeters@tuvnel.com Flow Consortium Phil Mark pmark@tuvnel.com Heavy Oil Chris Mills cmills@tuvnel.com Measurement Consultancy Craig Marshall cmarshall@tuvnel.com Chris Mills cmills@tuvnel.com Measurement Uncertainty Alick MacGillivray amacgillivray@tuvnel.com Meter Diagnostics Craig Marshall cmarshall@tuvnel.com MeterVue Phil Mark pmark@tuvnel.com Multiphase Terri Leonard tleonard@tuvnel.com PPDS Norman Glen nglen@tuvnel.com Single Phase Metering Bob Belshaw bbelshaw@tuvnel.com Training Helen Tulloch htulloch@tuvnel.comcom Umbilicals John Dods jdods@tuvnel.com Valve Testing John Dods jdods@tuvnel.com Wet Gas Emmelyn Graham egraham@tuvnel.com For general queries contact the sales team on sales@tuvnel.com

The National Measurement System is the UK s

51 The National Measurement System is the UK s national infrastructure of measurement laboratories, which deliver world-class measurement science and technology through four National Measurement Institutes (NMIs): LGC, NPL, the National Physical laboratory, NEL the former National Engineering Laboratory, and the National Measurement Office (NMO).

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