USER INTERFACE THERMODYNAMICS AND PHYSICAL PROPERTIES CC-STEADY STATE CC-THERM

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1 1of 9 USER INTERFACE 1. Management of user added data and user specified defaults: There has been a change in the logic governing where the program looks for user specified items such as engineering units default setting, user added components and symbols, user supplied BIP s, etc. Such items and specifications are now saved under the work folder instead of the parent folder. For clarity let us review the CHEMCAD Suite folder definitions: Files associated only with a specific flowsheet are located in the job folders. The job folder normally has the same name as the flowsheet. A folder containing multiple job folders is called a work folder. The folder to which the flowsheet looks for its default user added files (for components, symbols, engineering units, etc.) is called the parent folder. In the past it was possible in some circumstances for the parent folder to be different than the work folder. This is no longer the case. 2. K-Value Wizard: For all new jobs, the K-Value wizard automatically appears immediately after components have been selected. 3. Mapping between the CHEMCAD Suite and EXCEL: A generalized mapping tool is now available which makes it very easy to map CHEMCAD Suite variables to EXCEL worksheets and vice-versa. 4. Viewing/Editing components: A new quick way for viewing/editing components has been added. The user may view/edit the component by double clicking the component in the component list box. 5. Sensitivity Analysis: The user may now select whether he/she wishes to reset the manipulated parameters or keep final data. The user will be asked for his/her choice after running the study. THERMODYNAMICS AND PHYSICAL PROPERTIES 1. Henry s Constants: Henry s Constants have been added for chlorine, iso-butane, n-butane, and methyl mercaptan. 2. New Components: Seventy-five new components have been added to the standard database. All new data comes from DIPPR. 3. Electrolytes: The maximum number of electrolyte reactions has been increased to K-value and Enthalpy Options: The modified Peng-Robinson by Stryjek and Vera EOS has been added (PRSV). 5. Modified UNIFAC: New customized files have been added to allow those users who are members of the Modified UNIFAC consortium to automatically transfer the MUNIF data (groups, Q, R, and interaction parameters) into the program. Previously manual transfer was required. CC-STEADY STATE 1. Simultaneous-Modular flowsheet solver: The user may now choose between the modular sequential method and the simultaneous-modular method for solving the flowsheet. Selections are made on the Convergence dialog box on the Run menu. In most cases, the simultaneous-modular method will execute a flowsheet with recycle streams faster. 2. META Blocks: The user may now set up flowsheets as meta-blocks. These meta-blocks can then be inserted into other flowsheets and run as a block within that master flowsheet. Thus, flowsheets can be run within flowsheets using a simple insertion technique. 3. Compressor performance curves: Compressor performance curves can now be specified in terms of delta P in addition to previous options. 4. Equilibrium reactor: EREA (the equilibrium reactor UnitOp) can now be run with all reactions in series or all reactions in parallel; at the user s discretion. 5. Three-phase separator: A routine for sizing three phase separators has been added to the program. 6. Economic feasibility studies: The current capital costing feature will be expanded to include all of the features necessary for a complete cash flow analysis of the project. This expansion includes addition of such features as utilities usage, feedstock costs, product values, discounted cash flow analysis, and calculation of the project internal rate of return. 7. User Added Component Database: The user component and component database structures will be changed to allow for easier transfer of jobs (flowsheets) and more flexible data management. 8. Distillation columns: An additional simplified tabular printout for tray sizing has been added. It is now possible to choose between a detailed or simplified printout when sizing trays. The simplified printout includes major parameters such as flood percent and pressure drops. 9. SCDS column: More packing data has been added. 10. Spec Sheets: A new option for generating spec sheets for all UnitOps has been added. It is now possible to generate all spec sheets without selecting the UnitOps. CC-THERM 1. Falling Film Evaporators: The VDI method is now available in CC-THERM to calculate falling film evaporators. 2. Optimization Algorithm: An improved optimization algorithm for the design of shell and tube heat exchangers allows further searching of baffle variables until access area is approximately 5%. 3. Tube passes in optimization: The program will now optimize the number of tube passes when doing a design calculation for shell and tube heat exchangers.

2 2of 9 4. Non-Standard dimensions for shell and tube heat exchangers: CC-THERM will now calculate (for both design and rating mode) heat exchanger sizes (and part sizes) that are below those covered by TEMA, ASME, DIN, and BS5500. To invoke this capability, select the non-standard option from the TEMA Class/Standard field on the General Specifications dialog box. 5. Crossing and Parallel Flow: For shell and tube heat exchangers, there are now models for flow across a tube bundle (the standard model), flow parallel with the tube bundle, and mixed cross and parallel flow. The contribution made by each of the two types is a function of the baffle spacing. A weighted average of the two models is used when, 0.8D < B < D where, D = shell I.D. B = user specified baffle spacing If B 0.8D, the standard shell side cross flow methods are used (Bell, Delaware, or Stream Analysis). If B D, the parallel flow model is used exclusively. 6. Flooding in reflux condensers: CC-THERM now calculates the flood point for reflux condensers. 7. Partial condensation in reflux condensers: The reflux condenser model now handles partial condensers. 8. Pressure drop distribution: The Tabulated Analysis output report now contains a detailed breakdown of the pressure drop calculations as shown below. 9. Thermosyphon heat curves: The heat curve is now completely recalculated at the beginning of each iteration when calculating the circulation rate for a thermosyphon reboiler. 10. Vapor mole fraction spec for thermosyphons: CC-THERM now asks the user to specify the vapor mole fraction (instead of the vapor mass fraction) for thermosyphon reboiler calculations. 11. TEMA sheet properties: All vapor and liquid inlet and outlet stream properties are now printed out on the TEMA sheet. 12. Air Coolers: CC-THERM now calculates air coolers. (See attachments for description of this capability). 13. Plate and Frame Heat Exchangers: CC-THERM now calculates plate and frame heat exchangers for sensible/sensible service. (See attachments for description of this capability). 14. Runtime messages: Runtime messages are now displayed on the status line. 15. Quick tube counts: A quick method for determining how many tubes will fit into gives shell diameter has been provided as a simple utility function. CC-BATCH 1. Billet Mass Transfer Method: The Billet-Schultes mass transfer model is now available for the sizing/rating calculation of batch columns. 2. Stage limits: The limit of 100 stages has now been removed from CC-BATCH. CC-DYNAMICS 1. Dynamic Vessel static head: A new option has been added to DVSL to include the static head in the piping network calculation with liquid inlet and outlet streams. It is now possible to perform more realistic network dynamic calculations. If the user wishes to include the static head in the inlet stream calculations, the position of the nozzle may be input and the option 'include static head' must be checked. The static head comes from the height of liquid over the nozzle location. 2. Feedback controller in dynamics: The feedback controller UnitOp can now be used to impose constraints on dynamic simulations. 3. Control valve operation modes: The control valve UnitOp now has four operation modes: Normal Power failure Manually closed Manually open 4. Liquid only relief calculations: The BREA (batch reactor) and DVSL (dynamic vessel) UnitOps can now flow 100% liquid through the safety relief vent if the calculation determines this to be the actual situation. Previously, some vapor had to be present in the flow through the safety vent.

3 3of 9 5. RAMP controller unit: Users may now add random disturbances as wells as sine waves to stream and equipment parameters. 6. Turning off pumps: It is now possible to turn pumps off. When pump is turned off or malfunctional the flow rate through the pump is set to zero. 7. Operator Training System: Some UnitOps and parameters have been improved to achieve a better operation of CC- DYNAMICS with the CHEMCAD OPERATOR TRAINING SYSTEM (CC-OTS). CC-REACS 1. Three-phase calculation in CC-ReACS: An improved algorithm for the calculation of VLL equilibrium in the dynamic CSTR has been added to the program. 2. User specified rate expression: The speed of calculation of user added rate expressions has been improved when used in sensitivity analysis or optimization calculations. 3. User specified wall volume: The user may now explicitly specify the reactor wall volume for the thermal mass calculation. 4. Thermal Mode: A new thermal mode has been added to the batch reactor. They user may now specify the vapor rate and pressure and have the program calculate the heat duty. PIPING NETWORKS 1. Network Solver: A new, faster, more robust solver has been added to the program for the calculation of piping networks. This enables the program to handle large piping networks quickly and accurately. 2. Jain friction factor: The user can now choose between the Jain friction factor method or the Churchill friction factor method for calculating the pressure drop across a pipe segment. The Jain method is now the default. 3. Sonic flow in networks: The option to allow sonic flow in a piping flow network is now available. Using this option, when sonic flow exists, the pipe outlet pressure will be greater than the downstream node pressure. 4. Gas expansion factor: The gas expansion factor can now be used in the calculation of compressible fluid flow through networks.

4 4of 9 INTRODUCTION TO CC-THERM AIR COOLER CC-THERM s AIR COOLER module is an integrated module for the design, rating, and fouling rating of air-cooled heat exchangers. It is fully integrated with the CHEMCAD Suite so process data is automatically transferred from CHEMCAD Suite flowsheets to the heat exchanger sizing program, and heating curves and physical properties data are automatically generated. EASY TO LEARN The input for CC-THERM s AIR COOLER is simple and concise. It is based upon the CHEMCAD Suite input system, so any user familiar with the CHEMCAD Suite will be able to operate CC-THERM with ease. TECHNICAL FEATURES 1. CC-THERM s AIR COOLER module handles the following applications: Sensible cooling Horizontal condensing Vertical condensing Reflux condensation 2. Three modes of calculation may be selected: i. Design The tube side inlet and outlet streams are taken from the flow sheet, the user supplies the fouling factors and airflow, and the program calculates the design of the exchanger. A full optimization of the bundle dimensions, tube length, and number of tube passes per bundle will be carried out. ii. Rating The tube side inlet and outlet streams are taken from the flow sheet and the user supplies the complete details of the exchanger geometry and dimensions, fouling factors, and airflow. The program determines whether the exchanger is too large or too small for the given application. iii. Fouling rating The tube side inlet and outlet streams are taken from the flow sheet and the user supplies the complete details of the exchanger geometry and dimensions and airflow. The program calculates the fouling factors required to obtain the specified performance from the exchanger. 3. The program has its own fin tube databank. This databank contains all necessary information describing fin tube geometry and characteristics from the manufacturers catalog. The user may specify his/her own fin tube data if so desired. 4. Dry wall and wet wall condensing can be accommodated. 5. Conservative and non-conservative condensing methods are available. 6. Fan data from the following manufacturers are provided in the program; Checo Moore Environment Element Corporation Aerovent Hudson METHODS TUBESIDE HEAT TRANSFER The tube side heat transfer coefficient is calculated differently for condensation and sensible flow. Condensation The program considers the following types of condensation: Horizontal Condensation Vertical Condensation Reflux Condensation The program calculates tube side condensation for horizontal condensers, vertical condensers, and reflux (or knock-back) condensers for in-tube condensation. The algorithm for the condensation calculation in the air cooler program is similar to that used in the shell and tube program. The exchanger is always broken into n (default=10) different zones. The two principal heat transfer mechanisms occurring (shear-controlled condensation and gravity-controlled condensation) are computed. In between these two extreme zones, the calculation is considered to be in the transition region between shear controlled and gravity controlled flow. For a condenser where the inlet quality is 100% and the outlet 0%, the flow regime usually is shear-controlled at the inlet, goes through the transition region, and finally, is gravity controlled at the outlet. For horizontal condensation, two extreme cases are recognized; Stratified flow, which occurs at low vapor velocities, and Annular flow, which occurs at high vapor velocities.

5 5of 9 Stratified flow forms when the influence of vapor shear is low, and condensate, which forms at the tube wall, drains under the influence of gravity to form a stratified layer at the bottom of the tube. In this regime a drainage region forms along the top and sides of the tube, the stratified layer forms at the bottom, and a (predominantly) vapor region forms in the center, as illustrated below: Drainage Region Annular flow forms when the vapor shear force is much greater than that of gravity, causing the stratified layer to disappear. A fairly uniform layer of liquid forms at the tube wall, as shown below: For gravity controlled (stratified) flow, CC-THERM s AIR COOLER uses the methods of Chaddock and Chato, to determine the heat transfer coefficients. For annular flow, the methods of Nusselt, McNaught and Taborek are available to the user. In the transient region, a geometrically weighted average of the two regime coefficients is applied. In vertical tube condensation, filmwise condensation is considered. Again, the gravity controlled and shear controlled mechanisms apply. The program uses the Dukler method for gravity condensation in vertical tubes. The Nusselt treatment is adopted for laminar film. The calculation of two-phase properties and two-phase flow is an important part of an air-cooled condenser analysis. Of greatest importance is the determination of void fraction, two-phase density and two-phase pressure drop. For void fraction the program uses the method of Premoli et. al (1971). For two-phase density and pressure drop the CISE (Friedal) method is used. Multi-Component Condensation and the Effect of Non-Condensibles All above-mentioned methods are for condensation of a pure vapor and, as such, do not take into account the presence of non-condensibles or the effect of large temperature differences between the vapor dew point and bubble point. To account for the presence of non-condensibles or large temperature differences between inlet and outlet, a method similar to that suggested by Silver and Bell & Khaly is utilized. For each step along the condensation curve, the program calculates a resistance factor to include the combined effects of a large temperature difference and the presence of non-condensibles. The adjustment provided by this resistance factor can be critical, as even the presence of only a small amount of noncondensibles can have a pronounced effect on the condensing coefficient. Sensible Flow The Sieder-Tate equation is employed for the calculation of the tube side heat transfer coefficient in the turbulent region. The method of Martinelli and Boelter is utilized for laminar flow in a vertical tube. The method of Eubank and Proctor is used for laminar flow in horizontal tubes. These correlations combine the effects of natural convection and forced convection. The flow is assumed to be laminar below a Reynolds number of 2000 and is turbulent above a Reynolds number of In the transition region, the program prorates the laminar and turbulent coefficient according to the Reynolds number to arrive at the final coefficient. The program uses the familiar Poiseuille s law for the friction factor in the pressure drop calculation for laminar flow. For turbulent flow and for the transition region between laminar and turbulent flow, the recommendations made in Section 5.23 of Perry are followed. AIRSIDE HEAT TRANSFER For the airside, the program uses the ESDU method for staggered tube arrays and the method of Schmidt for in-line arrays.

6 6of 9 ZONE ANALYSIS For all exchangers, the unit is analyzed using zones specified by the user. CC-THERM s AIR COOLER module automatically sets up the zones and properties of each zone, but permits the user to edit or override any or all values calculated by the program. OUTPUT FEATURES The user may select from the following output: A zone-by-zone print-out of the heat curve and fluid physical properties API datasheet A detailed print-out of overall exchanger values A zone-by-zone print-out of heat transfer and pressure drop calculations The stream information inlet/outlet with H, T, P, and component flow rates Optimization data You can request any of the above outputs to be opened in Microsoft Word or Word Pad by using the View menu and conveniently view, edit, or print out the results. Also, the Plot menu is available at any time for the graphic display of the most important profiles, such as temperature, heat transfer coefficient, and heat flux. The edit heat curve facility also provides the user with an opportunity not only to view the heat curve but also to make any changes to the data that may be necessary. SUMMARY OF AIR COOLER As an integrated module to the CHEMCAD Suite, CC-THERM s AIR COOLER module offers the process engineer an easy and comprehensive method of sizing or rating air-cooled heat exchangers. Since it uses the same command language as the CHEMCAD Suite, any user can pick up the program in a matter of minutes. The program has been thoroughly and rigorously tested and found to be an accurate and reliable tool. It is fully supported by a staff of trained engineers. We believe it will be an indispensable tool for the library of the process engineer.

7 7of 9 INTRODUCTION TO CC-THERM PLATE AND FRAME CC-THERM s PLATE AND FRAME module is an integrated module for the rating and fouling rating of plate and frame heat exchangers. It is fully integrated with the CHEMCAD Suite so process data is automatically transferred from CHEMCAD Suite flowsheets to the heat exchanger program, and heat curves and physical properties are automatically generated. EASY TO LEARN The input for CC-THERM PLATE AND FRAME module is simple and concise. It is based upon the CHEMCAD Suite input system, so any user familiar with the CHEMCAD Suite will be able to operate the PLATE AND FRAME module with ease. TECHNICAL FEATURES 1. CC-THERM s PLATE AND FRAME module, at the present time, handles only sensible to sensible heat transfer, which constitutes about 90% of all plate and frame applications. 2. Two modes of calculation may be selected: rating and fouling rating. a. Rating The inlet and outlet streams are taken from the flow sheet and the user supplies the complete details of the exchanger geometry and dimensions and fouling factors. The program determines whether the exchanger is too large or too small for the given application. b. Fouling rating The inlet and outlet streams are taken from the flow sheet and the user supplies the complete details of the exchanger geometry and dimensions. The program calculates the fouling factors required to obtain the specified performance from the exchanger. 3. Film coefficients may be calculated by the program or specified by the user. 4. Chevron, Intermating and user specified plates can be handled. The dimensions, geometry, and properties of the plates may be user specified if so desired. 5. Multiples cold side and hot side passes can be calculated. The LMTD correction factor is applied in such cases. Multiple pass performance factors are also applied. 6. A plate materials database is provided with the program. 7. Pressure drops are calculated for both sides of the best exchanger. METHODS PLATE HEAT TRANSFER The total rate of heat transfer between the hot and cold fluids passing through a plate heat exchanger may be expressed as Q = UA Τ Μ Where U is the overall heat transfer coefficient, A is the plate area, and Τ Μ is the effective temperature difference. U is dependent upon the heat transfer coefficients in the hot and cold streams and is strongly influenced by the shape of the plate corrugations. Τ Μ is a function of the fluid temperatures, stream heat capacities, and heat exchanger configuration. Film coefficients in the PLATE AND FRAME module are based upon the projected area of the exchanger, which is defined as: A = Na = N x L x W where, N = number of plates a = projected area of a single plate L = plate height W = plate width Consistent with all heat transfer calculations in the CHEMCAD Suite, the overall heat transfer coefficient is calculated as the one over the sum of all the heat transfer resistances from one bulk fluid to the other. The film heat transfer coefficient, h, is dependent on the fluid velocity, fluid properties, and plate geometry. Heat transfer correlations for specific plate designs are obtained experimentally and the data are frequently proprietary to the manufacturers. In the PLATE AND FRAME module, the following correlations are used. In the view of Chemstations, these provided good, representative values in the absence of information from the manufacturer.

8 8of 9 Film coefficient and friction factor correlations for interning plates Film coefficient and friction factor correlations for chevron plates Effects of chevron angle on plate heat The above charts illustrate several important features of corrugated plate heat transfer. First, it is clear that the Reynolds number at which transition from laminar flow occurs ( 10) is less than that for smooth walled pipes, and the transition region is correspondingly extended. Second, the heat transfer coefficients in the transition and turbulent flow regimes are several times those for a smooth walled channel of the same equivalent diameter. This enhancement is, of course, the desired object of the corrugations. In practice, plate heat exchanger manufacturers offer a very wide range of plate geometries, so that the degree of heat transfer enhancement can be selected to suit the particular application. For example, the angle β, at which the chevrons are inclined to the overall direction of flow has a dramatic effect. PLATE PRESSURE DROP The price of enhanced heat transfer is increased pressure drop: plate corrugations not only increase Nu, they also increase f. For example, the values of friction factor shown in the above charts for turbulent flow are much higher than those for an equivalent smooth passage; the ratio is about 15 for the intermating troughs and about 60 for the chevrons. In laminar flow, however, the increase in friction factor due to the corrugations is much smaller, being roughly a factor of 2. This is consistent with the modest heat transfer enhancement in laminar flow and is associated mainly with the fact that the true surface area is greater than the projected area, on which f is based, and the effective fluid path length is greater than L.

9 9of 9 The effect of chevron angle on pressure drop is very significant. As shown above the friction factor for a given value of β divided by the value for β = 30 0 varies with β for various values of Reynolds number. The ratio reaches a value over 30 at β = 75 0, where the maximum heat transfer enhancement occurs. In calculating the total pressure drop associated with a plate-and-frame heat exchanger account is also taken of the hydrostatic head difference between inlet and outlet, and the pressure loss associated with the inlet and outlet ports, manifolds, and pipe work. OUTPUT FEATURES The user may select from the following output: The I/O steams information report The heat curves flows, temperatures, heat duties, and physical properties A detailed tabulated analysis report You can request any of the above output to be opened in Microsoft Word or WordPad by using the View menu and conveniently view, edit, or print out the results. The editing heat curve facility provides you with an opportunity not only to view the heat curve but also to be able to access the contents of the heat curve and make any changes to the data that you may require.