CFD modeling and optimization of a cooling pond

CFD modeling and optimization of a cooling pond Sylvain Devynck TechnipFMC - Ph.D., CFD Engineer Aurélien Davailles TechnipFMC - Ph.D., CFD Engineer STAR Global Conference 2017 March 6-8, 2017 Berlin

Agenda - TechnipFMC : who we are - Our history with STAR-CCM+ - Using CFD as a design tool in studies involving large size geometry modeling - Focus on the revamping of a phosphate fertilizer plant - Going further? Integration of HEEDS in our workflow

TechnipFMC : who we are A global leader in subsea, onshore/offshore, and surface projects

Broadest portfolio of solutions for the production and transformation of oil and gas Subsea Onshore/Offshore Surface Page footer text 4

Three major operating segments A unique global leader in oil and gas projects, technologies, systems, and services that will enhance the performance of the world s energy industry A comprehensive and flexible offering from concept to project delivery and beyond Subsea Onshore/Offshore Surface Subsea products Trees, manifolds, controls, templates, flowline systems, umbilicals, and flexibles Subsea processing ROVs and manipulator systems Subsea projects Field architecture, integrated design Engineering, procurement, construction, and installation Subsea services Drilling Installation, completion and life of field Asset management Well intervention and IMR ROVs and manipulator systems We bring strong technical, technological, and project management expertise across fixed, floating, and onshore facilities, as well as offshore services. Onshore Gas monetization, refining, petrochemicals and fertilizers, onshore pipelines, furnaces, and mining and metals Offshore Fixed platforms (jackets, self-elevating platforms, GBS, artificial islands) Floating facilities (FPSO, semi submersibles, Spar, TLP, FLNG) Services Project management consultancy, process technologies Drilling, completion and production wellhead equipment, chokes, compact valves, manifolds and controls Treating iron, manifolds and reciprocating pumps for stimulation and cementing Frac-stack and manifold rental and operation services Flowback and well testing services Advanced separation and flowtreatment systems Flow metering products and systems Marine, truck and railcar loading systems Installation and maintenance services Page footer text 5

Where we are in the world Legend EMIA operating centers TechnipFMC headquarters Business units 44.000 48 126 employees countries nationalities represented 6

Expertise & Modeling department position within TechnipFMC Global Business Unit Expertise & Modeling Advanced Process & Safety modeling Onshore/Offshore Regional Business Units Europe, Middle East, India and Africa (EMIA) Knowledge Management Paris Operating Center Process and Technology division Expertise & Modeling Operational Expertise - CFD - Equipment modeling - Dynamic process modeling - Thermodynamic - Flow assurance Accidental/Safety Expertise 7

Our history with STAR-CCM+ 8

Our history with STAR-CCM+ Key dates 2014 Test of STAR-CCM+ in order to improve our capabilities to model large & complex geometries 300 m 50 m Technip FLNG 9

Our history with STAR-CCM+ Key dates 2014 Test of STAR-CCM+ in order to improve our capabilities to model large & complex geometries Combining our know-how and the technical possibilities of STAR-CCM+, we managed to significantly reduce the averaged time to perform some types of studies About 30% time saved in our typical pollutant dispersion / HAR study workflow Input file : STL Wrap result Remesh result 10

Our history with STAR-CCM+ Key dates 2014 Test of STAR-CCM+ in order to improve our capabilities to model large & complex geometries 2015 First Hot Air Recirculation study performed using STAR-CCM+ for one of our offshore project FSI simulations (STAR-CCM+ and Abaqus) to assess the impact of sloshing in our equipments 2016 Use of STAR-CCM+ as an additional design-exploration tool for the revamping study of a phosphoric acid plant 2017 Test of HEEDS to enhance our capabilities and our efficiency regarding design-exploration 12

Use of CFD as a design tool in studies involving large-size geometry modeling Focus on the revamping of a phosphate fertilizer plant Page footer text 13

Industrial context Revamping of a phosphate fertilizer plant The process Phosphoric acid is manufactured by adding sulfuric acid to phosphate rock Source : Google Earth Wet process generates a by-product : phosphogypsum (5tons/tons of acid) Mixed with water Slurry Settling ponds/gypstacks (up to ~ 50 m) Closed loop Problematic Gypstack expansion over time Loss of cooling surface Alteration of cooling pond nearby environment Need to optimize the remaining cooling surface in order to maximize the heat transfer 14

CFD model Geometry Starting from 2D terrain line data we can generate a 3D faceted file (.STL) Import in STAR-CCM+ Creation of an atmospheric box [5 km²] Wrap + repair surface Building of the ponds (variable depth) repair surface + remesh Creation of the inlets and outlets of the domain Generation of volume mesh CAD software STAR-CCM+ 15

CFD model Boundary conditions Pond side Inlet Outlet Active configuration Air side Wind profile on domain inlet 16

CFD model Boundary conditions Pond side Inlet Outlet Future configuration Air side Wind profile on domain inlet 17

CFD model Interface exchange modeling between 2 fluid zones Defining two different fluid zones allows to lighten the modeling No multiphase model required Limit the mesh size Heat transfer Mass transfer Defined via «Data mappers» Atmosphere Water gain Mass transfer Evaporation f(v, T a, T p, α) Convection f(v, T a, T p ) Pond Heat loss Solar load 18

CFD model Results Heat flux density Temperature Wind 3 rd pond is of significant importance to provide the required process duty : [~30 % of total] 19

Going further? Integration of HEEDS in our workflow Increase the capabilities of our CFD tools

Integration of HEEDS in our workflow Use only CFD restricts our capabilities Good for assessment / troubleshooting studies Limited capabilities regarding design-exploration Easier access to computational power has opened new possibilities for CFD in our projects Softwares such as HEEDS are extremely valuable to move towards this direction Assess the relative effect of different parameters of a given process Efficient exploration of the best design taking into account several constraints and/or objectives Identify quickly trends / best design practices 21

Pond optimization with HEEDS How to enhance the heat transfer? Optimization parameters Manage the water interface Increasing the surface temperature Avoid dead zones Maximizing exchange surface Number of dikes (1 10) Orientation (horizontal / vertical) Aperture (10 200 m) Depth (0.5 5 m) Performance objectives Minimize outlet temperature Minimize CAPEX (dikes length) Definition of number of runs Determine optimal designs given the allowed time for the study Local minimum vs Global minimum 22

Pond optimization with HEEDS Identify quickly trends depending on the chosen parameters Build experience! 25

Pond optimization with HEEDS Identify quickly trends depending on the chosen parameters Build experience! Understand the connections between the different parameters 26

Pond optimization with HEEDS Identify quickly trends depending on the chosen parameters Build experience! Understand the connections between the different parameters Assess the relative effect and weight of each parameters 27

Pond optimization with HEEDS Identify quickly trends depending on the chosen parameters Build experience! Make final decision regarding the selected design 28

Pond optimization with HEEDS Comparison base design vs best designs Base design [No dikes 2 m depth] Design X [6 horiz. dikes, large opening, small depth] T outlet : 44.43 Estimated margin error : 0.2 C (5% duty) T outlet : 43.81 C Heat duty gain : 15.2% 29

Pond optimization with HEEDS Comparison base design vs best designs Base design [No dikes 2 m depth] Design Y [1 horiz. dike, large opening, small depth] T outlet : 44.43 Estimated margin error : 0.2 C (5% duty) T outlet : 43.65 C Heat duty gain : 19 % 30

Conclusions and way forward 31

Conclusions and way forward A CFD model of the cooling ponds of a large phosphate fertilizer complex has been developed and validated with site measurements CFD can provide valuable informations regarding the pond efficiency Safety and environmental issues can also be addressed using this model (acid fog formation, fluor dispersion,..) 32

Conclusions and way forward To go further and make CFD a real option for the early design-exploration phases of industrial projects involving large-size complexes, the use of softwares like Optimate or HEEDS can be a major asset Through the example of the revamping of a phosphate fertilizer complex we explored the possibility to combine HEEDS and STAR-CCM+. What did we learn? Parametrization of large size geometry (requiring wrap operation) is complicated but manageable Trends regarding the relative effects of several parameters can be quickly established which leads to the development of best practices Project manager is then better equipped at the time to take important design decision Include this methodology in our R&D studies will strengthen our know-how regarding the best practices to handle hot air recirculation and pollutant dispersion issues for our offshore and onshore installations 33

Sylvain.Devynck@TechnipFMC.com Aurelien.Davailles@TechnipFMC.com