Technology and Economic Comparison between Conventional Steam Stripping versus Direct Devolatilization of elastomeric polymer solutions

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1 Technology and Economic Comparison between Conventional Steam Stripping versus Direct Devolatilization of elastomeric polymer solutions Author: Dr. Ronald Oertel VDI; V-E-S-Ingenieurberatung, Merseburg, Germany Arisdorf, 22. Oct

2 Curriculum Vitae: Curriculum Vitae: Process Engineering Study at the Technical University Merseburg, GDR 1965 Doctoral dissertation at three phase reaction engineering From : Chemische Werke Buna at several senior process engineering executives for polymer processes as PVC, PE; PVAC, synthetic Rubber Form 2009 From 1995 to 2009: Lead process Engineer synthetic rubber at Dow Olefinverbund GmbH, Site Schkopau, Germany, currently Trinseo Freelance Process and safety Engineer The Association of German Engineers (VDI); Leader of the Process Engineering Party Middle Germany 2

3 0 Table of Contents: 1. Solution Polymerization Technology for Elastomers/Rubber 2. Process Flowsheet: Stripping Technology 3. Process Flowsheet: Direct Devolatilization Technology DDT-Process 4. Example System: 5 tons/h Polybutadiene Plant in Hexane 5. Example System: Stripping Technology 6. Example System: Direct Devolatilization Technology DDT-Process 7. Example System: Energy Consumption Comparison 8. Example System: Energy Costs Comparison 9. Example System: Plant Cost Comparison 10. Operation, Environmental and Product Quality Aspects 11. Summary 3

4 1 Solution Polymerization Technology for Elastomers/Rubber - State of the Art Monomer(s) Solventpurification Solvent- Water-Separation Vaporcondensation Waste Gas Treatment Monomerpurification Solution Polymerization Blending Stripping Waterseparation Drying Waste Water- Treatment Baling, packaging Cleaned Water Rubber Polymersolution (Cement) Crumbs-Water- Suspension (Slurry) Rubbercrumbs 4

5 1 Solution Polymerization Technology for Elastomers/Rubber with DDT-Process Monomer(s) Solventpurification Solvent- Water-Separation Vaporcondensation Waste Gas Treatment Monomerpurification Solution Polymerization Blending Waste Water- Treatment Baling, packaging Cleaned Water Rubber Polymersolution (Cement) Crumbs-Water- Suspension (Slurry) Rubbercrumbs 5

6 1 Solution Polymerization Technology for Elastomers/Rubber with DDT-Process Monomer(s) Solventpurification Solvent- Water-Separation Vaporcondensation Waste Gas Treatment Monomerpurification Solution Polymerization Blending Direct Devolatilization Technology (DDT-Process) Waste Water- Treatment Baling, packaging Cleaned Water Rubber Polymersolution (Cement) Crumbs-Water- Suspension (Slurry) Rubbercrumbs 6

7 1 Solution Polymerization Technology for Elastomers/Rubber 7

8 2 Process Flowsheet: Stripping Technology (generalized) 8

9 3 Process Flowsheet: Direct Devolatilization Technology DDT-Process 9

10 4 Example System: Best Technology? Stripping Technology or Direct Devolatilization Technology Investigation of an example system 5 tons / h Polybutadiene Plant in Hexane Approach? There are plant models for both technologies. Model basis: Process Flowsheets (PFD) Material- and energy balances Cost estimation (OPEX/CAPEX) (Process Flowsheets of both technology are simplified for the presentation) Final comparison of energy, product quality and environmental facts 10

11 4 Example System: 5 tons/h Polybutadiene Plant in Hexane Simplified Flowsheets both Technologies Output: Rubber Solvent Gas Waste Air Wet Solvent & rec. Solvent Waste Water Input: Cement MPS LPS Electricity Water 11

12 4 Example System: 5 tons/h Polybutadiene Plant in Hexane Product Limitations: Polymerization Catalyst- and Stabilizer-System will be not considered Costumer specific Process Temperature Limitation < 140 C Rubber grade specific Consistency in Mooney viscosity Residual Components in Rubber: Utility Constraints: ± 0,5 Mooney-unit Moisture < 0,5 ma% Residual Butadiene < 1 ppm Residual Solvent as low as necessary (until < 10 ppm possible) Type of Utility T P Middle Pressure Steam [MPS] 203 C 16 barg Low Pressure Steam [LPS] 151 C 4 barg Cooling-water 28 C 4 barg Hot-water 90 C 4 barg Chilled-water 5 C 4 barg Deionat/Processwater 35 C 4 barg Cooling-Air 33 C 0 barg 0,5 kv-power 6 kw-power 12

13 4 Example System: 5 tons/h Polybutadiene Plant in Hexane Rubber Production (Polybutadiene) = 5 tons/h Interface after Polymerization unit Polymer solution (Cement): Butadiene conversion = 96 % Total solid Content = 15 ma% Cement Temperature = 75 C Cement Composition: [j] kg/h ma% Butadiene 208 0,62% Rubber ,91% Hexane ,47% Tot. Mass feed ,00% Tot. Volume feed 52,4 m³/h Temperature 75 C 13

14 5 Example System: Stripping Technology Stripping Unit Conditions: Rubber Crumb Concentration Slurry: 5% Crumbs size is a function of cement nozzle design (Example: 15 mm) Optimized Low Pressure Steam (LPS) to Coagulator and Strippers 1. Vessel = Coagulator vessel (MPS, LPS) to form Rubber crumbs at 14% Solvent Concentration in Rubber crumbs to evaporate Solvent and Water (thermodyn. Equilibrium) 2. / 3. Vessel = Stripping vessel (LPS) to stripp out Solvent from Crumbs to evaporate Solvent and Water (thermodyn. Equilibrium) to improve stripping conditions [j] Input B701 Output Coagulator Output Stripp. 1 Output Stripp. 2 y[j]-only Mon; m[j] Solv y[j]* in Pol. y[j]* in Pol. y[j]* in Pol. kg/h kg/h ma% ma% ma% Butadiene 208 0,7% 0,1022% 0,0006% 0,0000% Hexane ,3% 13,9% 0,5870% 0,0248% Total ,0% 14% 0,5876% 0,0248% Residence Time 20 min 20 min 20 min Factor MPS 0,115 kg[mps]/kg[cem.] Factor LPS 0,600 kg[lps]/kg[cem.] LPS Distribution to Coagul. & Strippers 53% 28% 19% 14

15 5 Example System: Stripping Technology Cement, Slurry and Rubber Path: [j] Waste Air kg/h % Sum Hydrocarb. 0,132 0,0016% Air % Water % Tot. Mass feed 8426 kg/h Tot. Volume feed 8737 m³/h [j] Rubber kg/h % Butadiene 0 0% Rubber ,48% Hexane 1,1 0,02% Water 25,1 0,50% Tot. Mass feed 5026,2 kg/h [j] kg/h ma% Butadiene 208 0,62% Rubber ,91% Hexane ,47% Tot. Mass feed ,00% Tot. Volume feed 52,4 m³/h Temperature 75 C Water from U800 kg/h m³/h [j] Slurry to Unit 800 kg/h % Butadiene 0,000 0% Rubber % Hexane 1,240 0,0012% Water % Tot. Mass feed kg/h Tot. Volume feed 105 m³/h Waste Water kg/h m³/h 15

16 5 Example System: Stripping Technology Vapor Path: [j] Solvent Gas kg/h Butadiene 208 Hexane 404 Water 6 Tot. Mass feed 617 Tot. Volume feed 121 m³/h [j] Wet Solvent kg/h Butadiene 0 Hexane Water 1,4 Tot. Mass feed Tot. Volume feed 43 m³/h [j] V001 V002 V003 Vapor, total m[j] m[j] m[j] m[j] kg/h kg/h kg/h kg/h Butadiene , Hexane Water Tot. Mass feed % 13% 8% 100% Condensation output = kw! 92 % Air Cooling 0 % Cooling Water Cooling 8 % Chilled Water Cooling 16

17 6 Example System: Direct Devolatilization Technology DDT-Process Cement and Rubber Path: [j] After Pre-Concentr. Unit kg/h % Butadiene 25 0,1% Rubber % Hexane % Tot. Mass feed Tot. Volume feed 34 m³/h [j] After SEV-Unit kg/h % Butadiene 1 0,0% Rubber % Hexane % Tot. Mass feed 5682 Tot. Volume feed 6 m³/h [j] kg/h ma% Butadiene 208 0,62% Rubber ,91% Hexane ,47% Tot. Mass feed ,00% Tot. Volume feed 52,4 m³/h Temperature 75 C [j] After TDE-Unit / Rubber kg/h % Butadiene 0 0% Rubber ,6% Hexane 0,05 0,0010% Water 20,08 0,4% Tot. Mass feed 5020 Tot. Volume feed 5 m³/h 17

18 6 Example System: Direct Devolatilization Technology DDT-Process Vapor Path: [j] Solvent Gas kg/h ma% Butadiene % Hexane % Water 0,25 0,02% Tot. Mass feed 1219 Tot. Volume feed 386 m³/h [j] Recycl. Solvent kg/h % Butadiene 0 0% Hexane % Water 0 0% Tot. Mass feed Tot. Volume feed 40 m³/h [j] Wet Solvent kg/h ma% Butadiene 1,0 0,15% Hexane ,5% Water 2,5 0,36% Tot. Mass feed 680 Tot. Volume feed 1 m³/h [j] From Pre-Concentr.-Unit From SEV-Unit From TDE-Unit kg/h ma% kg/h ma% kg/h ma% Butadiene 184 1,44% 24 0,16% 1,068 0,06% Hexane ,6% ,8% ,6% Water 0 0% 0 0% % Tot. Mass feed Tot. Volume feed 3574 m³/h 5222 m³/h 2378 m³/h [j] Waste Water kg/h ma% Butadiene 0,010 0,0008% Hexane 0,677 0,0552% Water ,94% Tot. Mass feed 1228 Tot. Volume feed 1,2 m³/h 18

19 6 Example System: Direct Devolatilization Technology DDT-Process Condensation Conditions: Condensation output = 3548 kw! 0 % Air Cooling 76 % Cooling Water Cooling 24 % Chilled Water Cooling [j] From Pre-Concentr.-Unit From SEV-Unit From TDE-Unit kg/h ma% kg/h ma% kg/h ma% Butadiene 184 1,44% 24 0,16% 1,068 0,06% Hexane ,6% ,8% ,6% Water 0 0% 0 0% % Tot. Mass feed Tot. Volume feed 3574 m³/h 5222 m³/h 2378 m³/h 19

20 7 Example System: Energy Comparison Stripping Technology: DDT-Technology: 20

21 7 Example System: Energy Comparison Stripping Technology: Total Energy = 3585 kwh/t[rb] 21

22 7 Example System: Energy Comparison DDT-Technology: Total Energy = 1336 kwh/t[rb] 22

23 7 Example System: Energy Comparison -63 % 23

24 8 Example System: Energy Cost Comparison (part of OPEX) Energy Prices (average for Example System): Costs Middle Pressure Steam 17,000 /ton Low Pressure Steam 17,000 /ton Cooling-water 0,015 /m³ Chilled-water 0,440 /m³ Deionat/Processwater 1,250 /m³ Cooling-Air - 0,5 kv-power 50 /MWh 6 kw-power 50 /MWh -62 % 24

25 8 Example System: Energy Cost Comparison (part of OPEX) Energy Prices (average for Example System): Costs Middle Pressure Steam 17,000 /ton Low Pressure Steam 17,000 /ton Cooling-water 0,015 /m³ Chilled-water 0,440 /m³ Deionat/Processwater 1,250 /m³ Cooling-Air - 0,5 kv-power 50 /MWh 6 kw-power 50 /MWh The steam and electric costs are the main energy cost of both techniques! The steam and electrical energy cost by the total energy costs accounted for 85 % 76 % 25

26 8 Example System: Energy Cost Comparison (part of OPEX) Energy Prices (average for Example System): Costs Middle Pressure Steam 17,000 /ton Low Pressure Steam 17,000 /ton Cooling-water 0,015 /m³ Chilled-water 0,440 /m³ Deionat/Processwater 1,250 /m³ Cooling-Air - 0,5 kv-power 50 /MWh 6 kw-power 50 /MWh Cost Ratio Steam Cost Electr. Power Cost C total Energy const. 26

27 8 Example System: Energy Cost Comparison (part of OPEX) Cost Ratio Steam Cost Electr. Power Cost 27

28 8 Example System: Energy Cost Comparison (part of OPEX) Cost Ratio Steam Cost Electr. Power Cost 28

29 9 Example System: Plant Cost Comparison Stripping Technology: Plant Costs: 100 % DDT-Technology: Plant Costs: 119 % Cost Estimation Methodology with Lang Factors: Estimate +25% / -15%; Prices Basis 2014 John S. Page: Conceptual Cost Estimating Manual; 2nd edition; Gulf Professional Publishing,1996 Work Breakdown Structure Element Graduation Lang-Factor Equipment Installation normal 0,38 Piping normal 0,59 Insulation normal 0,11 Electrical normal 0,22 Instrum. & Process Control high 0,35 Buildings, incl. Services low 0,15 Structural Steel high 0,19 Yard improvements normal 0,07 Engineering & supervision low 0,75 Construction expense normal 0,48 29

30 9 Example System: Plant Cost Comparison Production Cost Model: C total C ROI C other C Energy ROI Return of Investment Other Maintenance, Service, Cleaning, etc. Energy Sum of Energy C Stripping Techn. ROI 100% C DDT Techn. ROI 119% C Stripping Techn. other C DDT Techn. other C C DDT Techn. total Stripping Techn. total C C Energy total 30

31 10 Operation, Environmental and Product Quality Aspects Stripping Technology: DDT-Technology: Operation Cost Energy Consumption higher lower Plant Operation higher lower Plant Cleaning Effort higher lower Solvent Purification higher lower Environmental Off Gas cleaning (Incineration) necessary not necessary Waste Water cleaning higher lower Product Quality low temperature; low shear higher lower continuous steady state condition worse better 31

32 11 Summary Monomer(s) Solventpurification Solvent- Water-Separation Vaporcondensation Waste Gas Treatment Monomerpurification Solution Polymerization Blending Direct Devolatilization Technology (DDT-Process) DDT-Technology Benefit (per ton Rubber) Energy Cost - 62% Plant Cost + 19% Production Cost - 33% Product Quality less stress Environmental Aspects closed & clean Waste Water- Treatment Cleaned Water Baling, packaging Rubber Final evaluation is depending on local requirements and need to be discussed in detail 32

33 Many Thanks for your Attention! 33