Dortmund Data Bank (DDB) DDB Software Package (DDBSP)

Transcription

1 Showcase on Technology Dortmund Data Bank (DDB) DDB Software Package (DDBSP) Practical Application of Distillation Synthesis for NOx Reduction, Energy Cost Savings, & Improved Environmental Compliance Dr. Juergen Rarey, Managing Director, DDBST, Oldenburg Germany, Todd J. Willman PE, ChemE, MBA, EPCON International, Houston, TX, 1

2 Aspects to be Considered During the Synthesis of Separation Processes sepproc5_e.cdr Benzene (2)?? T 12 = x 1 Distillation? Crystallization? Ethanol (1) Water (3) Residue Curve Construction 1 2 P1 s P2 s 1? Suitable Solvent for Extractive or Azeotropic Distillation? y 1 x 1? Separation Problems? AB A C Separation Process? N th =? Column Height?? ABCD? S = n [2(n-1)]! n! (n-1)! T n Bedeutung CD B D Sequence? 2

3 Advantages of Distillation Compared to Other Separation Processes scheme of a separation process energy/entrainer to generate different streams Feed Stage i Streams of different composition Advantages of distillation processes compared to other separation processes a) Energy as "entrainer" b) Simple phase separation due to large difference in density between liquid and vapor phase c) Simple transport of fluid phases helps to realize large number of stages d) Long time experience (estimated throughput in 1992: 5.2*10 9 t/a) Disadvantages of distillation High energy consumption In 1989 approx. 3% of the total US energy consumption was required to operate distillation columns Synthese Due to these advantages distillation is also used for the separation of azeotropic mixtures 3

4 Residual Curves intermediate boiling component Vapor Liquid x (t) Simple Distillation Boundary Acetone T b= 56.1 C P = 1 atm 54.2 C x 0 = x (t=0) x 0 x 0 x 0 x (t) x (t) x (t) low boiling component high boiling component Benzene T b= 80.1 C 77.5 C Cyclohexane T b= 80.7 C _e AZD 4

5 Residual and Boundary Residual Curves C NMP 56.1 C Acetone 79.6 C 2-Butanone A) B) C) 54.2 C 78.4 C 71.2 C Benzene 77.5 C Cyclohexane Benzene 77.5 C Cyclohexane 80.1 C 80.7 C 80.1 C 80.7 C Benzene 77.5 C Cyclohexane 80.1 C 80.7 C AZD 5

6 Heteroazeotropic Distillation HeteroazeotropicDistillation.cdr Benzene (2) C C C C B C Ethanol Water A B B C D Benzene D Water Ethanol E Ethanol (1) C A C E Water (3) C Synthese 6

7 Residue Curves and Border Planes in the System Acetone(1) Chloroform(2) Methanol(3) - Ethanol(4) at 1 atm mod. UNIFAC (Do.), 1 atm stable node unstable saddle unstable node ResidueCurves+BorderPlane s.ppt (1) 56.4 C (2) 61.1 C (3) 64.9 C (4) 78.3 C (1)-(2) 64.3 C (1)-(3) 55.4 C (2)-(3) 53.7 C (2)-(4) 59.9 C (1)-(2)-(3) 57.6 C (1)-(2)-(4) 63.2 C 7

8 Product Regions in the System Water (1) + Ethanol (2) + Benzene (3) for Different Feed Compositions P = 1 atm Modified UNIFAC (Dortmund) Ethanol (2) C B ideal vapor phase (1)-(2)-(3) C (1)-(2) C (1)-(3) C (2)-(3) C F D c AZD Water (1) C B F D D F B Benzene (3) C 8

9 Azeotropic und Extractive Distillation Synthese 9

10 Coworkers of DDBST Ltd. 10

11 Scope of DDB 1 - Basic Data 2 - Experimental Data (from Literature) 3 Molecular Structures (ChemDB) 4 Model Parameters (ParamDB) 5 Literature Sources and Documents (LEAR) 6 COSMO -Profiles... 11

12 Status of the Dortmund Data Bank* (Sept. 2006) References, 1800 Journals, Compounds plus Salts, Adsorbents and Polymers (VLE) (HPV) VLE** 5920 (ELE) (total: data sets) data sets data sets for data points for pure solvents non-electrolytes Polymers new (E)SLE data sets 1120 data sets KOW data sets for solvent mixtures KOW for electrolytes 7250 data points he LLE DDB data sets 2150 data sets azeotr. data cpe data sets data points ve CRI Pure Component Properties ADS 1320 data sets 3500 data sets cp Pi S data sets data sets for non-electrolytes (E)GLE 1100 data sets for electrolytes * detailed information is available via internet ( ** including unpublished VLE data of companies from the former German Democratic Republic 12

13 Dortmund Data Bank Software Package (DDBSP) DDBSP_jumpstart.cdr; DDB - Mixture Data VLE h E ACT GLE LLE AZD SLE... Prediction UNIFAC Mod. UNIFAC (Do) ASOG PSRK... Recommended Values Wilson NRTL UNIQUAC SRK PR... Calculation Programs Phase Equilibria Simulation Programs Flash Points Process Synthesis DDB - Pure Component Data Pis c P crit. Tm h fus... Prediction Recommended Values Parameter Fitting UNIFAC Mod. UNIFAC (Do) PSRK LIQUAC PCP Presentation Programs Diagrams Tables experimental correlated predicted 13

14 Experimental and Predicted Azeotropic Data for the Quaternary System at P = kpa Benzene (1) - Cyclohexane (2) Acetone (3) - Ethanol (4) predicted (mod. UNIFAC (Do)) system type of azeotrope hompmax none hompmax hompmax hompmax none none hompmax none none none / C experimental* type of / C azeotrope hompmax 77.6 none hompmax hompmax hompmax 64.8 none none hompmax 64.9 none none n.a. y1,az y2,az y1,az y2,az * mean values of the experimental data stored in the Dortmund Data Bank n.a.: not available a AZD 14

15 Residual Curves in the System Ethanol (1) - Benzene (2) Water (3) at P=1atm HeteroazeotropicDistillation.cdr Benzene (2) C C C C C B D Ethanol (1)A C C AZD E Water (3) C 15

16 Entrainer Selection and Contour Lines separation factor of 1 up to 22 mol% of NMP < 0.65 properties along this line or parallel typically shown on solvent free basis <

17 Selection of Selective Solvents with the Help of Thermodynamic Models or DDB Selective_Solvent_Models_DDB.cdr Input: Examination of the binary VLE behavior Preselection of potential solvents with the help of predicted values i Output: List with selective solvents a) extractive distillation b) azeotropic distillation 1)... 2)... 3)... Recommendation of alternative distillation processes the case of: 1) Zeotropy 2) Heteroazeotropy 3) Strong pressure dependence of y az 4) Zeotropy at low (high) pressure Prediction of ternary azeotropic data ( solvent) Are solvents suitable? Input: Components Pressure (Temperature) Distillation Process Examination of the binary VLE behavior Search of binary data (azeotropic data, ) for component 1 and 2 DDB-MIX azeotropic data (45100 values) (36700 values) Output: List of suitable solvents including experimental information Recommendation of alternative distillation processes in case of: 1. Zeotropy 2. Heteroazeotropy 3. Strong pressure dependence of y az 4. Zeotropy at low (high) pressure Search of ternary data with component 1 and 2 Determination of 12 and Taz (Paz ) for given P(T) Selection criterion fulfilled? 17

18 Selection of Selective Solvents for Extractive Distillation Components to be separated: (1) Cyclohexane C6H12 Tb(2) = K (2) Benzene C6H6 Tb(1) = K DDB - access P = kpa azeotropic data for system (1) - (2): type of azeotrope : homogeneous pressure maximum, Tb = K modified UNIFAC (Dortmund) selective solvent (3) (1,2), inf. (T [K]) selective solvent (3) (1,2), inf. (T [K]) [EMIM] ethylsulfate N-Butylpyridinium BF4 [EdMIM] bis(cf 3SO2)imide [EMIM] bis(cf3so2)imide 4-Methyl-N-butylpyridinium BF4 Tetrahydrofurfuryl alcohol N-Formyl-morpholine Nitrobenzene N-Methyl-2-pyrrolidone Cyclohexanone Furfural Aniline Anisole (303.15K) (298.00K) (298.00K) (298.00K) (353.56K) 4.05 (300.15K) 3.80 (408.73K) 3.48 (397.02K) 3.45 (394.07K) 3.41 (293.15K) 3.29 (380.59K) 3.13 (387.94K) 3.05 (293.15K) Adipodinitrile 2,5-Hexanedione N-Methyl-2-pyrrolidone Furfural Aniline Acetophenone Triethylene glycol Nitrobenzene Cyclohexylamine 3-Methylphenol Tetrahydrofurfuryl alcohol Cyclohexanone Anisole 8.70 (353.56K) 4.95 (353.56K) 4.93 (353.56K) 4.11 (353.56K) 4.02 (353.56K) 3.83 (353.56K) 3.03 (353.56K) 2.88 (353.56K) 2.80 (353.56K) 2.10 (353.56K) 2.07 (353.56K) 2.06 (353.56K) 1.72 (353.56K) Synthese 18

19 Typical Result for the Search of Suitable Solvents by DDB Access Synthese

20 Typical Result for the Search of Selective Solvents with the Help of a Thermodynamic Model Synthese

21 Software Demonstration DDBSP Jumpstart 21

22 Conclusion Azeotropic conditions can be overcome (and energy reduced) by selecting a suitable solvent for azeotropic or extractive distillation, extraction this can be best accomplished using a large, highly accurate experimental data bank or powerful predictive models. The action of an entrainer for extractive distillation results from the different activity coefficients of the components to be separated in the entrainer. The greatest effect is usually observed when the components are infinitely diluted in the entrainer. The effect of the entrainer on the activity coefficients can result in an azeotropic point of one of the components with the entrainer. Solvent Selection either uses the DDB or the results of predictive models (UNIFAC, ) as a source for activity coefficients (ACT) or azeotropic data (AZD). The program is very powerful and has many important options, only very simple example were shown here. Running distillation separation processes under azeotropic conditions means that purity cannot be improved no matter what additional energy is added to the process. A column analyzed and optimized with Distillation Synthesis can have significantly reduced overall energy demands directly, positively impacting NOX reduction and environmental compliance. 22