Getting started with BatchReactor Example : Simulation of the Chlorotoluene chlorination

Transcription

1 Getting started with BatchReactor Example : Simulation of the Chlorotoluene chlorination 2011 ProSim S.A. All rights reserved.

2 Introduction This document presents the different steps to follow in order to simulate a batch reactor synthesis using BatchReactor software. This presentation is supported with an example: the chlorination of the chlorotoluene. This example is available in the BatchReactor example directory (reactor2.pbpr input file) The summary of this Getting Started is: Part 1 Description of the example Part 2 General points on the software interface Part 3 Description of the different steps to simulate the example

3 Part 1 Description of the example: - Description of the reaction system - Compounds and thermodynamic model - Description of the equipment - Operating mode

4 Description of the reaction system Gaseous chlorine is fed into a liquid chlorotoluene charge. The reaction takes place in liquid phase. A nitrogen sweeping is maintained during the reaction. The main reaction is as follow: C 7 H 7 Cl + Cl 2 C 7 H 6 Cl 2 + HCl Chloromethyl chloro benzene (ACl) and hydrogen chloride are produced. The reaction rate is found to be expressed with a partial order equal to 1 with respect to each reactant, a frequency factor K o = e17 mol/l.s and an activation energy E a = J/mol

5 Description of the reaction system 1-chloro-2-dichloro methylbenzene (dichloride) and hydrogen chloride are in turn formed in the following side reaction: C 7 H 6 Cl 2 + Cl 2 C 7 H 5 Cl 3 + HCl Its kinetic law is also expressed with a partial order equal to 1 for each of the reactants, K o = 580 mol/l.s and E a = J/mol The heat of the reactions are calculated from the standard enthalpies of formation at 25 C (perfect gas state).

6 Compounds and thermodynamic model The compounds involved in this synthesis are: -Chlorotoluene (CT) -Chloromethyl chloro benzene (ACl) -1-chloro-2-dichloro methylbenzene (dichloride) -Chlorine -Hydrogen chloride -Nitrogen The thermodynamic model selected is NRTL. The binary interaction parameters, expressed in cal/mol, are given in the following table: CT-ACl -707,3 775,31 0,1939 CT- Dichloride ,5 0,1584 ACl-Dichloride 64,339-79,04 0,4097

7 Description of the equipment Two feeds are connected to the reactor: the first is for the reactant and the second is for nitrogen sweeping. The reactor characteristics are: - Hemispherical vessel of 3m 3 volume, 1400 mm diameter - 3 blades impeller of 1120 mm diameter located at 300 mm from the bottom and rotating at 90 RPM - Baffled jacket (side and bottom), 50 mm thick and 1366 mm high - Wall thickness is 17 mm with a thermal conductivity of 15,3 W/m/K. - Reactor weight is 800 kg with a specific heat of 500 J/Kg/K - Utility fluid is steam at 6 bars and 200 kg/h or cooling water at 25 C and normal flowrate of kg/h. Heat transfer coefficients will be calculated for both process and utility sides. Thermal losses are neglected and no inserts are taken into account.

8 Description of the equipment The reactor is closed and equipped with a two-stage condenser. A vapor outlet is leaving the second stage and a liquid outlet collects both condensates that are returned back into the reactor (total reflux). The first stage of the condenser has an exchange area of 15 m 2 and a global heat transfer coefficient of 300 kcal/h.m 2. C. It is cooled by 3000 kg/h of water at 20 C. The second stage has an exchange area of 0,5 m 2 and a global heat transfer coefficient of 300 kcal/h.m 2. C. The service fluid is at -15 C with a flowrate of 100 Kg/h. Its specific heat is 0,7933 cal/g/k at -15 C. The pressure drop in both stages is neglected.

9 Operating mode The reactor is charged with kg of chlorotoluene at 25 C and atmospheric pressure. First step: heating Reactor is operated under total reflux until the temperature reach 58 C. Nitrogen flow is 1 kg/h at 25 C and atmospheric pressure. The total pressure is equal to the atmospheric pressure Second step: reaction The reactor is fed during 2 hours with 60 kg/h of chlorine at 3 bar. The nitrogen sweeping is maintained. The reactor temperature is controlled at a value of 62 C by acting on the cooling water flowrate. PID controller parameters are: - Minimum / maximum values: 59 C / 65 C - Type : feedback, Gain = -5, Ti = 500 s, Td = 0 - The valve is equal percentage with a Cv = Sampling time is 10 s.

10 Part 2 General points on the software interface: - The main window - Using the toolbar - Choosing the unit system - Creating a new simulation file

11 The main window Menu bar Toolbar Topology panel Scenario view Flowsheet view

12 Using the toolbar File management (new, open, save, save as, close) Synopsis Printing Sheet properties Copy, cut, paste, delete Copy flowsheet Compounds, thermodynamics, chemical reactions Viewing the compounds list Managing units Units conversion «Bulk» properties Numerical parameters Report parameters Starting the simulation Calculator Graphical objects (shapes, pictures, text) Connecting equipment, steps and events Viewing last simulation results

13 Choosing the unit system 1- Select a predefined system and click on Apply system 2- For a given quantity you can change the default unit to another one by clicking on its name 3- Click on OK to validate

14 Creating a new simulation file 1- Click on Create a new document icon 2- Save the file 3- Open the synopsis (optional) 4 Fill the form

15 Part 3 Description of the different steps to simulate the example Phase 1 : Selecting the compounds Phase 2 : Selecting the thermodynamic model Phase 3 : Describing the chemicals reactions Phase 4 : Describing the reaction system Phase 5 : Describing the operating mode Phase 6 : Running the simulation Phase 7 : Reviewing the simulation results

16 1-Selecting the compounds 1- Click on the thermodynamics and compounds icon 2- Double click on the calculator. A calculator allows you to define a list of compounds and a thermodynamic model 3- Click on open a compounds file In this example, the compounds needed for the simulation have been stored in a private database named chlorotoluene.compounds

17 1-Selecting the compounds Choose file 4- Select chlorotoluene.compounds Look in My recent documents Desktop My documents My computer Network File name File of type Open Cancel

18 1-Selecting the compounds 5- The compounds imported from the compounds file are listed. CT, chlorine, hydrogen chloride and nitrogen are from the standard databank. ACl and dichloride have been created by the user.

19 2-Selecting the thermodynamic model 1- Click on the Model tab to open the thermodynamic models configuration window. 2- All the available thermodynamic models are listed here. Use the scroll bar to go through the complete list. Select NRTL as the model to be used in the example.

20 2-Selecting the thermodynamic model Enter a name for the calculator (optional) 3- The NRTL profile is automatically displayed 4- Click on Binaries to access to the binary interaction parameters for the NRTL model

21 2-Selecting the thermodynamic model 5- You can enter your binary interaction parameters Click on OK at the bottom to exit the thermodynamic calculator editor

22 3-Describing the chemical reactions 1- Click on Edit the chemical reactions to enter the chemical reactions editor 2- Select Add a reaction

23 3-Describing the chemical reactions 3- Select the reaction type Kinetic in this case 4- Enter a name 5- Select the phase where the reaction takes place 6- Select Reaction heat tab

24 3-Describing the chemical reactions 7- Select the reaction heat model, From standard enthalpies of formation (1 atm, 25 Cn perfect gas) 8- Select the Kinetic tab

25 3-Describing the chemical reactions 9- Select Arrhenius and enter the value of the activation energy 10- Select the Compounds tab

26 3-Describing the chemical reactions 11- Enter the stoichiometric coefficients: <0 for reactants > 0 for products and the partial orders for the considered reaction 12- Select the Model tab

27 3-Describing the chemical reactions 13- Enter the frequency factor 14- Click on OK to validate and exit

28 3-Describing the chemical reactions 15- Add the second reaction (describe it as for the first)

29 4-Describing the reaction system The main flowsheet allows to display of the reaction system (inlet and outlet storages, reactor and condensing system) and provide direct access to the different windows allowing their description. 1- Select the calculation mode

30 4-Describing the reaction system 2- Select the relevant options: - Closed type - With a condenser - Hemispherical bottom - 3 retreating blades impeller - Baffled external jacket (joined)

31 4-Describing the reaction system 4.1- Feeds 1- Select Add a feed and click on the flowsheet view to add the second feed

32 4-Describing the reaction system 4.1- Feeds 2- Click on each storage and change its name: - N2 for the nitrogen feed - Cl2 for the chlorine feed The characteristics of each streams will be requested during the definition of the operating mode.

33 4-Describing the reaction system 4.2- Reactor 1 Double click on the reactor icon Enter the initial temperature and pressure Enter the total volume of the reactor Temperatures and volumes warning can be used to set constraints to the process (technical, safety ). Enter the values as shown.

34 4-Describing the reaction system 4.2- Reactor Click on head space Select Other and NITROGEN as the pressurizing compounds in the list (nitrogen blanketing)

35 4-Describing the reaction system 4.2- Reactor Select 3 retreating-blades impeller in the list Enter the diameter of the device and its distance to the bottom Click on Mixing device You can save your mixing system in the database managed by Simulis Technologies

36 4-Describing the reaction system 4.2- Reactor Click on Initial load Enter the composition and mass of the initial load

37 4-Describing the reaction system 4.2- Reactor Click on Wall heat-exchanger Enter the layout, the jacket characteristics and the geometrical parameters

38 4-Describing the reaction system 4.2- Reactor Enter the wall materials characteristics. One or two materials can be defined. Click on Wall materials

39 4-Describing the reaction system 4.2- Reactor Enter the characteristics of the vessel bottom Click on Vessel bottom geometry

40 4-Describing the reaction system 4.2- Reactor Select the validation tab. This tab displays the warning and error messages. If the data are correctly entered, this tab should be empty and the reactor icon is not highlighted anymore.

41 4-Describing the reaction system 4.2- Reactor The reactor icon is not highlighted anymore. The global validation system report other missing or not consistent information. That is normal as your file is under construction

42 4-Describing the reaction system 4.3- Condenser Enter the number of condensing stages. Two condensers in series can be defined Double click on Condenser

43 4-Describing the reaction system 4.4- Storage tanks 1 - Enter the name of the gas tank Double click on a tank 2 - Enter the name of the liquid tank

44 5-Describing the operating mode The description of the reactor operation is made in the scenario window by a succession of steps and events.

45 5-Describing the operating mode 2- Click on the scenario window. A new step and a new event will be created 1- Click on Variable heat duty step.

46 5-Describing the operating mode 2- Click on the first triangle (starting of the operation) and then click on the first step. A new connexion will be created. 1- Click on connexion.

47 5-Describing the operating mode 1- Select the first step (double click on the icon). A new tab, allowing to describe the step is created 2- Change the default name by HEATING 3- Double click on the N2 feed

48 5-Describing the operating mode 1- Select Feed is open 2- Enter the feed characteristics during this first step: Temperature Pressure Composition Total mass flowrate 3- Click on OK

49 5-Describing the operating mode Double click on the condenser to access to its detail view 1- Select Condenser is open 2- Select Calculated condenser and enter the number of stages is use: 2 3- Enter the operating parameter of the first condensing stage during this first step: Calculation type Heat exchange coefficient Exchange area Pressure drop Fluid type Inlet temperature Mass flowrate

50 5-Describing the operating mode Click on the second stage tab 1- Enter the operating parameter of the second condensing stage during this first step: Calculation type Heat exchange coefficient Exchange area Pressure drop Fluid type Inlet temperature Mass flowrate 2- Click on OK

51 5-Describing the operating mode 1- Double click on the reactor icon in the flowsheet view for the HEATING step to enter this view 2- Enter the operating parameters: Reflux ratio (enter 1 for total reflux) pressure specification 3- Click on Mixing parameters

52 5-Describing the operating mode Enter the operating parameter for the mixing device during this first step: Rotation speed

53 5-Describing the operating mode Click on Wall heat exchanger to enter the detail view and set the heating operating parameters during this step. 1- Select The wall heat exchanger is in use 2- Enter the operating parameters during this step: Fluid type (Saturated steam) Mass flowrate Pressure

54 5-Describing the operating mode 1- Double click on the HEATING step end event 2- Enter a name for the event 3- Select the type and enter the desired value for the event

55 5-Describing the operating mode Right click on the first step, enter the Duplicate to sub-menu and then select Specified TR with thermal device. This copy avoids to specify again most of the parameters for this new step.

56 5-Describing the operating mode Connect appropriately the new step to the ending event of the HEATING step and to the final simulation event

57 5-Describing the operating mode Double click on the Cl2 feed 1- Select feed is open 2- Enter the feed characteristics during this second step: Temperature Pressure Composition Mass flowrate 3- Click on OK

58 5-Describing the operating mode 1- Double click on the reactor icon 2- Select PID 3- Enter the temperature set point and the minimum and maximum values allowed 4- Enter the minimum and maximum values for the flowrate 5- Click on PID to enter the detail view

59 5-Describing the operating mode 1- Enter the controller parameters 2- Enter the valve parameters (type and Cv) 3- Click on OK

60 5-Describing the operating mode 1- Double click on the event 2- Enter a name for the event 3- Select time spent since the beginning of the step 4- Enter the desired duration 5- Click on OK

61 6-Running the simulation Click on Report parameters Select the desired options for the presentation of the report Save the file Click on Start the simulation

62 6-Running the simulation You can hold the calculation during the simulation ( Pause ) to review the evolution of the different parameters

63 6-Running the simulation Once the simulation is completed, click on Results to visualize the simulation results

64 7-Reviewing the simulation results Various graphs are plotted versus time. Use the buttons to browse into the available graphs Allows to review the coordinates (X,Y) of the selected series as a function of the cursor location on the displayed graph

65 7-Reviewing the simulation results Access to the report and review of: - the reactor characteristics - the mass and energy balances versus time for each operating step. - the mass balance at the end of each step.

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