Prospectus

PROSPECTUS 2020

TABLE OF CONTENTS DSP-11 ............................................................................................................................................ 9 Plastic Random Packing............................................................................................................. 9 DSP-12 .......................................................................................................................................... 10 Small Random Packing Test .................................................................................................... 10 DSP-13 .......................................................................................................................................... 11 Mixed Packing Test .................................................................................................................. 11 DSP-16 .......................................................................................................................................... 12 Efficiency & Operating Limits of Packed Oxygen Strippers .................................................. 12 DSP-17 .......................................................................................................................................... 13 Spray Nozzle Entrainment from Low Surface Area Y and X Style Structured Packings, Grid and Random Packing at Deep Vacuum.................................................................................. 13 DSP-19 .......................................................................................................................................... 14 Effects of Liquid Viscosity and Surface Tension on Structured Sheet Metal Packing......... 14 DSP-20 .......................................................................................................................................... 15 Effect of Gap Between Distributor and The Top of a Packed Bed ....................................... 15 DSP-21 .......................................................................................................................................... 16 High Capacity Wire Gauze Tests ............................................................................................. 16 DSP-22 .......................................................................................................................................... 17 Packing Material of Construction Effects ............................................................................... 17 DSP-24 .......................................................................................................................................... 18 Effect of Thermowell Insertion Depth into Random and/or Structured Packed Beds....... 18 DSP-25 .......................................................................................................................................... 19 Performance of Structured Packing Modified for Dividing Wall Columns .......................... 19 DSP-26 .......................................................................................................................................... 20 Improved Understanding of Impact of Bed Depth on Random and Structured Packing Efficiency................................................................................................................................... 20

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DSP-27 .......................................................................................................................................... 22 Measuring Distribution Quality in the Top Section of Packed Beds.................................... 22 DST-1............................................................................................................................................. 25 Tray Blowing............................................................................................................................. 25 DST-4............................................................................................................................................. 26 3-Pass Trays.............................................................................................................................. 26 DST-6............................................................................................................................................. 27 System Limit on Trays.............................................................................................................. 27 DST-13 .......................................................................................................................................... 28 Dynamic Model Verification of Tray Performance ................................................................ 28 DST-14 .......................................................................................................................................... 29 Baffles on Dualflow Trays........................................................................................................ 29 DST-16 .......................................................................................................................................... 30 Simulator Test – Effect of Intermediate Pressure Drop Device on Capacity in a Fouling Service....................................................................................................................................... 30 DST-17 .......................................................................................................................................... 31 Simulator Study to Improve Tray Pressure Drop Correlation to Predict Flow Distribution ................................................................................................................................................... 31 DST-19 .......................................................................................................................................... 32 Packed Downcomers to Stop Vapor Entrainment ................................................................ 32 DST-20 .......................................................................................................................................... 33 Measurement of Entrainment between Dual Flow Trays..................................................... 33 DST-24 .......................................................................................................................................... 34 Intertray Mist Elimination........................................................................................................ 34 DST-25 .......................................................................................................................................... 35 Tray Efficiency and Capacity Enhancements ......................................................................... 35

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DST-26 .......................................................................................................................................... 36 Efficiency Capacity Increase by Adding Packing Below Tray Deck....................................... 36 DST-27 .......................................................................................................................................... 37 Effects of Sealing on Downcomers......................................................................................... 37 DST-28 .......................................................................................................................................... 38 Stepped Weirs .......................................................................................................................... 38 DST-29 .......................................................................................................................................... 39 Angle Iron (Aka Shed Decks) Performance Correlations ...................................................... 39 DST-30 .......................................................................................................................................... 40 Impact of Movable and Fixed Mini-Valves on Tray Performance ........................................ 40 DST-31 .......................................................................................................................................... 42 Performance of Large Fixed-Valve Trays under Vacuum ..................................................... 42 DST-32 .......................................................................................................................................... 43 Investigating Performance of Two-Weight Valve Units on 1-Pass Valve Tray..................... 44 DST-33 .......................................................................................................................................... 46 Impact of Gross Installation Failure on Tray Performance .................................................. 46 MD-1 ............................................................................................................................................. 49 Review of State of the Art of Computed Mass Transfer (CMT) and Computational Fluid Dynamics (CFD) ........................................................................................................................ 49 MD-2 ............................................................................................................................................. 50 Partner with Experimental Fluid Dynamics Laboratory........................................................ 50 MD-3 ............................................................................................................................................. 51 Use of Binary Methods on Computer Process Simulator Results ....................................... 51 MD-4 ............................................................................................................................................. 52 Rate Based Systems................................................................................................................. 52 MD-5 ............................................................................................................................................. 53 Dividing Wall Column Simulation Work ................................................................................. 53

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MD-9 ............................................................................................................................................. 54 Impact of Density Difference Between Vapor Density and Liquid Density on Capacity Correlation................................................................................................................................ 54 OR-1 .............................................................................................................................................. 57 Improving Quality of FRI Test Data......................................................................................... 57 OR-2 .............................................................................................................................................. 58 Improving Quality of FRI Test Data Reboiler De-Entrainment (Part 2) ................................ 58 OR-3 .............................................................................................................................................. 60 Heat Transfer in Empty Spray Sections in Vacuum Systems................................................ 60 OR-4 .............................................................................................................................................. 62 Study Alternate Separation Process....................................................................................... 62 OR-5 .............................................................................................................................................. 63 Plant Tests ................................................................................................................................ 63 OR-6 .............................................................................................................................................. 64 Heat Transfer in Pump-Around Zones ................................................................................... 64 OR-7 .............................................................................................................................................. 66 Improving the Existing Distillation Test Unit to an Innovative/New Research Facility....... 66 OR-8 .............................................................................................................................................. 68 Operation of an Air/Water Simulator ..................................................................................... 68 OR-9 .............................................................................................................................................. 69 CO 2 Absorption Studies ........................................................................................................... 69 OR-11 ............................................................................................................................................ 70 Kettle Reboiler Entrainment.................................................................................................... 70 OR-12 ............................................................................................................................................ 71 Dividing Wall Column Experimental Work............................................................................. 71 OR-13 ............................................................................................................................................ 72 Column Dumping Predictions................................................................................................. 72

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OR-14 ............................................................................................................................................ 73 Flashing Feed Designs ............................................................................................................. 73 OR-15 ............................................................................................................................................ 74 Entrainment Removal in High Vapor Density or Low Surface Tension ............................... 74 PPP-2............................................................................................................................................. 77 Mass Transfer Efficiency – Steam Stripping of Toluene from Water ................................... 77 PPP-3............................................................................................................................................. 78 Mass Transfer Efficiency – Steam Stripping of an Organic Less Volatile than Toluene ..... 78 PPP-5............................................................................................................................................. 79 Suitability of Dynamic Models for Relief Valve Loading........................................................ 79 PPP-6............................................................................................................................................. 80 Column Draw-Offs ................................................................................................................... 80 PPP-7............................................................................................................................................. 81 Distillation with Two Liquid Phases Present.......................................................................... 81

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As a world premier research consortium, FRI continues to conduct cutting edge research on distillation and strive to provide more values to the FRI Members. To perform this effectively, the research items in the prospectus are divided into two categories: Developmental and Traditional Research Ideas . Developmental Research Projects generally refer to innovative and fundamental research items. Traditional Research Projects mainly focus to better understand the performances of column internals and provide insight into the distillation column design, revamp and troubleshooting

NOTATION Key

DSP

Device Specific Projects / Packing

DST

Device Specific Projects / Trays

MD

Modeling / General

MDP

Modeling / Packing

MDT

Modeling / Trays

OR

Opportunity Research Projects

PPP

Physical Phenomena Projects

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CHAPTER Device Specific Projects Packings (DSP) 1

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DSP-11 Plastic Random Packing Expected Benefit toMembers:

Traditional Research Idea

Plastic packing is common in scrubbers for pollution abatement. Regulatory requirements require performance data in the permits. Poor performance predictions can lead to costly problems in explaining performance deviations from the permit. Correlations for the predicting the pressure drop and capacity of plastic packing are not available from FRI for plastic packing. A generalized correlation valid for multiple plastic packing would also increase confidence in new designs. Present Situation and Proposed Research: FRI has not tested any plastic packing. FRI has developed correlations for high void fraction metal packing. A test of plastic packing would show whether those correlations could be extended to plastic packing that have lower void fractions. As stated in the recent FRI Topical Report No. 147 of January 2003, the "new models are for metal random packing only and are not valid for packing made of other materials." Proposed Internals and Test System:

Background and Discussion: The models in Topical Report No. 147 have the desirable characteristic that they avoid any packing specific parameters associated with the packing type. This allows the correlation to be broadly applicable to many metal packings. Extending this correlation to plastic packing would allow better prediction of column size in particular pollution abatement scrubbers. This would also allow proper permitting of pollution abatement columns.

One plastic packing in the four-foot column. (There is some desire for smaller sizes of packing rather than larger sizes.) Estimated Unit Time: Three weeks of testing with the C6/C7 system. (No high-pressure data would be obtained.) Flood data would be measured at various liquid rates. Obtain efficiency at total reflux. Estimated Additional Costs (Beyond Unit Time): Unknown.

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DSP-12 Small Random Packing Test Expected Benefit toMembers: Small random packing is often used for the separation of fine chemical systems. They have large specific area and consequently, have a low HETP. Present Situation and Proposed Research: Carbon steel 5/8” Pall rings were tested with the C6/C7 system at 5 and 24 psia in 1982. The results are documented in Progress Report for July-August 1982 and September-October 1982. These tests found that the measured HETP strongly depends on the liquid distributors used. Multiple cross samplers that was shown to increase HETP in recent studies were used. The combination of poor distributor quality and use of cross samplers might have resulted in higher HETP than expected. In 1986, stainless steel 5/8” Pall rings was test with the C6/C7 system at atmospheric pressure using the FRI adjustable liquid distributor (Progress Report for January-February 1986). Eight cross samplers were employed. The test results show that the HETP of 5/8” Pall ring was higher than that of 1” Pall ring (Figure 14 in the Progress Report). Again, these results are unexpected. Proposed Internals and Test System: Traditional Research Idea

Estimated Unit Time: Three weeks of unit operation time and two weeks of installation are required to measure the HETP, pressure drop and capacity for the C6/C7 system at 5 and 24 psia. Estimated Additional Costs (Beyond Unit Time): Unknown.

Additional tests with 5/8” rings using modern liquid distributors without in bed samplers are necessary to validate the old data and to confirm and extend the TR152 model. For data consistency, 5/8” stainless steel Pall rings may be used. Other packing such as Super Ring ® , Nutter ring, and IMTP ® can also be considered for practical purposes. Two modern liquid distributors will be used for the test.

Background and Discussion: Topical Report No. 152 concluded that all HETP data for 5/8” Pall rings in the FRI database are elevated by using cross samples or low-quality liquid distributors. All these data were not used in the TR152 HETP model. TR152 HETP model shows that HETP is inversely proportional to the packing area raised to a power of 0.8. All these findings need to be verified by experimental data.

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DSP-13 Mixed Packing Test Expected Benefit toMembers: Improved performance of packed towers by retrofitting with mixed beds and improved new tower design. Present Situation and Proposed Research: The concept of using mixed beds of random packing has been proposed and touted as providing the pressure drop performance of the large packing and the efficiency of the smaller. Patents have been issued in the area and would need to be explored before proceeding. A test of the concept at SRP has been reported, but the results have not been widely used. Proposal Conduct a patent review to ensure the members can use any experimental work. Test a mixed bed of two sizes of Pall rings and compare against prior tests of those two sizes. Proposed Internals and Test System: Standard. Estimated Additional Costs (Beyond Unit Time): Unknown Estimated Unit Time: Total column time of six weeks as follows: • One week for initial installation • Two weeks’ operation with the first mixed bed • One week to install a bed with different percentages of the two sizes Two weeks’ operation with the second mixed bed Background and Discussion: The basics of this concept were originally developed by Belko, and patents related to the concept were issued to Belko and later transferred to AMACS. A test was conducted at SRP and appeared to be successful, but has not been widely accepted within the membership. An independent test at FRI would provide a credible gauge of the concept. Traditional Research Idea

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DSP-16 Efficiency & Operating Limits of Packed Oxygen Strippers Expected Benefit toMembers: The proposed experiments are intended to determine the effects of liquid loading, stripping gas ratio, and a partial bubble column operation on the stripping efficiency of packed oxygen strippers. The results from this FRI experimental work will provide guidance to FRI member companies on optimizing future grassroots and revamp designs of oxygen strippers and other towers with very high liquid/vapor ratios. Present Situation and Proposed Research: Oxygen strippers are used in refineries and chemical plants to remove dissolved oxygen in low boiling range and middle distillate hydrocarbon streams to avoid fouling of process equipment. Some packed oxygen stripper designs have not achieved their expected stripping efficiency performance. These towers typically operate with relatively high liquid loadings and very low vapor loadings of stripping gas because of the very high relative volatility of oxygen to most hydrocarbon liquids. The field efficiency data are less-than-expected in this service. A 20-ft. deep bed of nominal 1” size random packing (preferably IMTP 25 or 1” Pall rings) in a 24” diameter pipe sleeve installed in one of the 4-ft. diameter FRI columns should be used. Perform stripping tests at liquid loadings of 40, 60 and 80 gpm/ft2 of tower cross-sectional area. For each liquid loading, four stripping gas ratios should be used at lambda values of 1.5, 3, 6, and 12 and atmospheric pressure. The experiments described above are then repeated with the liquid level in the column raised to submerge half or more of the packed bed to simulate a partial bubble column. Proposed Internals and Test System: Developmental Research Idea

Estimated Unit Time: One operating week for each internal, total unit time 6 weeks. Estimated Additional Costs (Beyond Unit Time): Unknown

para/ortho xylene system at close to atmospheric conditions; C6/C7 system at close to atmospheric conditions.

Background and Discussion: To help plan the FRI experimental program, smaller scale tests with a simple test system such as stripping oxygen from water with nitrogen should be considered at a contract research facility before proceeding to the FRI column test.

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DSP-17 Spray Nozzle Entrainment from Low Surface Area Y and X Style Structured Packings, Grid and Random Packing at Deep Vacuum Expected Benefit toMembers: To quantify/compare the amount of spray nozzle liquid re-entrainment from the surface of a large crimped size sheet metal structured packing (both “Y” and “X” styles), grid packing, and random packing. This research would help fractionation specialists and designers specify the appropriate packing type at the top of a packed bed to minimize the loss of wash oil wetting (due to spray droplet re-entrainment) in low liquid rate wash zone sections in critical deep vacuum fractionator services. Present Situation and Proposed Research: Spray nozzle performance has been characterized at FRI in 1966, 1982, 1985 and 1997. The 1985 tests employed 1 and 7 nozzles from Spraying Systems to characterize spray distribution quality on the performance of 1-inch Pall Rings. HETP’s with the 7-spray nozzle system were better than with the single spray nozzle. In 1997, heat transfer studies were performed using a short bed of Intalox 4T structured packing and three single wide-angle spray nozzles. Test systems included C6/C7 at 24 psia totally condensing system and partially condensing C6/C7 with methane gas. Heat transfer was almost instantaneous for both systems. The tests in the 4 ft. LP section of the FRI unit in Stillwater, OK will simulate wash oil entrainment in which the entrained drop size distributions can be measured using the FRI/OSU owned Phase Doppler Interferometer (PDI). The pressure drop across the spray nozzles and the liquid rate would be metered for vapor rates (Cs-Factors) from 0.1 to 0.4 ft./s. Proposed Internals and Test System: Traditional Research Idea

Estimated Unit Time: o/p xylene system at 65-75 mm Hg. Estimated Additional Costs (Beyond Unit Time): One operating week for each internal, total unit time 10 weeks.

Lechler 423.148 or 423.208 spray nozzle as the liquid distributor; Flexipac ® 3YS or Mellpak™ 125 Y (smooth surface) or equivalent, Flexipac ® 3XS or Mellpak™ 125 X (smooth surface) or equivalent, Flexigrid ® #3 or F-Grid 3 or equivalent, 3rd or 4th generation random packing.

Background and Discussion: Optimizing the wash oil flow rate is key to preventing coking in a vacuum pipestill wash bed. To prevent coking in a wash bed, the desired true overflash (not including entrained residuum) is 0.1 gpm/ft2 (minimum) leaving the bottom of the packed bed. However, uncertainty about the amount of entrained residuum in the overflash, along with the notoriously poor reliability of overflash flowmeters, can make it extremely difficult to determine whether the 0.1 gpm/ft2 target is reached. Insufficient liquid to remove entrained residue from the wash bed packing leads to the formation of coke. Accelerated wash bed coking can be attributed to the loss of wash oil due to vaporization or re-entrainment from the top of the packed bed.

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DSP-19 Effects of Liquid Viscosity and Surface Tension on Structured Sheet Metal Packing Expected Benefit toMembers: Developmental Research Idea

Understanding of liquid properties on efficiency, pressure drop and capacity. Adjustment parameters, or a correlation for each of these would be useful for troubleshooting and rating existing designs and optimizing new applications. Present Situation and Proposed Research: The current work as OSU is studying viscosity effects on Oldershaw columns and entrainment. I haven't found the proposal to know how far that study plans to go and if there is already a plan to go in this direction or not. Proposed Internals and Test System: Structured sheet metal packing - test systems varying in viscosity

and surface tension. Estimated Unit Time: Unknown. Estimated Additional Costs (Beyond Unit Time): Unknown. Background and Discussion: None.

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DSP-20 Effect of Gap Between Distributor and The Top of a Packed Bed Expected Benefit toMembers: Establish a safe range between being too close (entrainment) and too far away (poor distribution due to vapor effect on liquid streams. Present Situation and Proposed Research: None. Proposed Internals and Test System: Unknown. Estimated Unit Time: Over random packing and structured packing. Estimated Additional Costs (Beyond Unit Time): Traditional Research Idea

Could be an add on test by just adding some height adjustment capability to the distributor.

Background and Discussion: None.

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DSP-21 High Capacity Wire Gauze Tests Expected Benefit toMembers: Better understanding of high-performance gauze packing. Present Situation and Proposed Research: For example, Sulzer BX and Koch Glitsch AX and any others. Proposed Internals and Test System: Use same test systems used for Montz wire gauze packing. Estimated Unit Time: Unknown. Estimated Additional Costs (Beyond Unit Time): Unknown. Background and Discussion: None.

Developmental Research Idea

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DSP-22 Packing Material of Construction Effects Expected Benefit toMembers: Surface effects of plastic, ceramic, metal and carbon materials for the same packing. Effects on efficiency, pressure drop, and capacity. Present Situation and Proposed Research: None. Proposed Internals and Test System: Test hydrocarbon and aqueous systems if possible. Random and structured packings where possible Estimated Unit Time: Unknown. Estimated Additional Costs (Beyond Unit Time): Unknown. Background and Discussion: None. Traditional Research Idea

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DSP-24 Effect of Thermowell Insertion Depth into Random and/or Structured Packed Beds Expected Benefit toMembers: How much does temperature change across the bed at one elevation? We are curious because of the strange temperature profiles we see sometimes and wonder if by-passing has something to do with it and not knowing if the bulk of the bed is operating OK or not. Proposed Internals and Test System: Could be a hydrocarbon systems or water and hot air at different V/L and temperature differences but done in a way that good liquid and vapor distribution are expected. Estimated Unit Time: Unknown. Estimated Additional Costs (Beyond Unit Time): Unknown. Background and Discussion: None. Traditional Research Idea Improved installation and design know-how. Present Situation and Proposed Research:

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DSP-25 Performance of Structured Packing Modified for Dividing Wall Columns Expected Benefit toMembers: Dividing wall columns (DWC) are becoming more common in commercial applications, especially for applications associated with the production of chemicals. It would be of value to the industry to demonstrate the performance (e.g. efficiency, pressure drop and capacity) of semicircular layers of packings with wall wipers manufactured for dividing wall columns to aid in development. This is not a demonstration of an operating DWC. Instead, we propose do standard FRI performance tests to demonstrate the impact of semicircular shapes of packed beds on efficiency, pressure drop and capacity. Present Situation and Proposed Research: It is proposed to install a divided wall bed into the 4-foot diameter section of the LP Column and repeat the test for the same packing in the 8-foot section of the LP Column to evaluate the impact of the sharp corners at the edges, with wall wipers, of semicircular layers of packings. Proposed Internals and Test System: A commercial structured packing with a commonly used specific surface area of about 250 m 2 /m 3 with o/p-xylene system at 75 and 760 mmHg; and C6/C7 at 23.5 psia in the LP column, 4 foot and 8-foot section. Estimated Unit Time: Total 12 weeks unit time, including 6 weeks for revamps and 6 weeks for data collection. Estimated Additional Costs (Beyond Unit Time): Unknown. Background and Discussion: None. Developmental Research Idea

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DSP-26 Improved Understanding of Impact of Bed Depth on Random and Structured Packing Efficiency Expected Benefit toMembers: Ability to reduce costs of new facilities by installing deeper packed beds. Present Situation and Proposed Research: FRI currently uses the same correction for bed depth for both random and structured packing: HETP avg = HETP * (0.8 + 0.04 * (H/ HETP) 0.7 . The correlation was developed from only five data points for structured packing (two systems, 5 FT, 12FT & 19FT) and two data points for random packing (one system, 12 and 19). In TR-143, it is noted that the empirical parameters in Equation (30) may need to be adjusted when more experimental data are available. The effect of bed length on the HETP may also be related to the liquid and vapor loadings and system physical properties. However, these factors are not included in Equation (30) due to limited experimental data. TR-152 for random packing efficiency has a similar disclaimer, but it has disappeared from more recent efficiency reports like TR-209. There is very little information in the literature on just how bad efficiency loss is from deep beds of random and structured packing, and the information that does exist is conflicting. Rukovena and Koshy (Ind Eng. Chem Res. 1993, 32, 2400-2407) report data on structured packing at packed depths up to ~38FT with no appreciable change in HETP, and cite case studies of even deeper beds working efficiently. The proposed research comprises two phases: 1. Review existing data: FRI Staff to review experimental results since 2002, including recent insights into short beds from the DSP-1 Intermediate Bed Limiter work, to see what additional data we might have that would let us refine the correlation. Staff also to review any results from well-documented publications (the Rukovena-Koshy paper and any other more recent papers), for possible insights that would allow refining the correlation. Staff also to explore getting access to unpublished SRP results on bed depth effects, perhaps in trade for FRI data pertinent to this topic. Staff to give thought as to a less-empirical model structure for efficiency loss with packed depth. Developmental Research Idea

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DSP-26 Improved Understanding of Impact of Bed Depth on Random and Structured Packing Efficiency (cont…) 2. Gather new data and update model: Exact experimental plan to be determined based on the learnings from Phase 1. As a placeholder, assume one system (o/p-xylene) at one pressure with a high-quality modern liquid distributor. Use a small random packing (RSR #0.6 or equivalent) to increase stage count in the bed. Install bed depths of 5FT, 10FT, 15FT and 20FT, keeping the elevation of the bottom of the bed the same each time, and lowering the distributor to be the same distance above the top of the bed for each case. Repeat the test with a medium-surface area Y-style high capacity packing (Mellapak 452Y or equivalent). Update model based on results of both phases of work Proposed Internals and Test System: Random and Structured Packing, o/p-xylene @ 1 atm. Estimated Unit Time: 8 weeks. Estimated Additional Costs (Beyond Unit Time): Unknown. Developmental Research Idea

Background and Discussion: See present situation section.

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DSP-27 Measuring Distribution Quality in the Top Section of Packed Beds Expected Benefit toMembers: Measuring quality of distribution exiting a short bed of packing can lead to a knowledge and understanding that may improve initial distribution in the top of a bed by adjusting distributor and packing designs. Better initial distribution may lead to the ability to design for taller beds and improve efficiency in any bed. Developmental Research Idea

Present Situation and Proposed Research: We have quantitative tests already for measuring initial quality of distribution from point type distributors and some methods for predicting distribution quality from line type distributors, but we speculate what the quality of distribution is in the first 1 foot or so of random packing or exiting the first two layers of structured or wire gauze packings. Proposal is to test/improve the idea of wetting index using different types of distributors (point, line, different pour point density, etc.) and set over various packings of varying short heights and configurations. Random packing and structured packing and measure the distribution quality exiting the packing. Could set up a 4ft diameter cylinder and use equipment/packing that FRI already has available. But would need to set up a test stand. We would learn from water tests, but it would be better if we could come up with a safe solution that had physical properties closer to more common applications. This could be done by a couple of undergrad students. Also, with and without bed limiter and even adding that cross-sampler to verify if it creates macro

maldistribution. Also do this with plastic and ceramic packing (random and structured). We also have questions about fouling accumulation (coke, fines, resins, salts, etc.) and the ability of packings to pass fouling and dependency of liquid rate on clearing the fouling. FRI has not done a comprehensive and systematic study on this field. It is a very good but a big project. It may be considered dividing in phases, such as SP, RP, Plastic and fouling. The important and critical part of this project is to design and build a test stand and develop a measurement system to assess the liquid distribution quality under the packings quickly and consistently. Once a test stand and methodology are developed to collect the data, testing different internals may be relatively quick. It is a good project for undergraduate students. But it may need a MS student to develop the measurement system. FRI and collaborators had experiences to vary the liquid viscosity and surface tensions, which can be used for this study.

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DSP-27 Measuring Distribution Quality in the Top Section of Packed Beds (cont…) Proposed Internals and Test System: See above Research Facility: Could be FRI, Tianjin, or a University such as OSU Estimated Unit Time: Not available at this time Estimated Additional Costs (Beyond Unit Time): Minimal other than labor Background and Discussion: This idea came about from the papers on wetting index, and Tony's experiments of running a garden hose of water on top of structured packing in his back yard a couple of years ago. Developmental Research Idea

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CHAPTER Device Specific Projects Trays (DST) 2

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DST-1 Tray Blowing Expected Benefit toMembers:

Traditional Research Idea

The probability of sieve tray or valve tray blowing is increased as designs move to higher vapor velocities. The tray designer needs additional information to confidently design trays to avoid “blowing.” A large economic incentive exists to avoid field erected columns. In order to reduce the column diameter, the designer needs to be able to confidently design at higher vapor velocities using higher (36 inch) tray spacing.

Present Situation and Proposed Research: Within the body of F.R.I. information, there are no guidelines or correlations to predict the loss of a liquid layer on the tray. As vapor rates increase, increased spray action causes more liquid to be blown into the downcomer. Since there is a fixed amount coming onto the tray, there is a loss of liquid on the tray. Simulator work is proposed to understand the relative importance of high vapor velocity, low hole area, downcomer design, and high tray spacing on the blowing mechanism.

An improved tray will then be tested under a range of distillation conditions. Proposed Internals and Test System: One sieve tray design with 36-inch tray spacing and design features to prevent blowing. The systems will be xylenes and C6/C7. Estimated Unit Time: Simulator Required. Column: Three weeks for each system. Estimated Additional Costs (Beyond Unit Time): None

Background and Discussion: Blowing is defined here as the loss of liquid inventory on the tray. Conditions of high vapor velocity and low liquid rate promote blowing. If sufficient liquid is lost on the tray, the downcomer seal can be lost and vapor will travel up the downcomer causing flooding. Inlet weirs have been shown by FRI to prevent the loss of downcomer seal, but the installation of inlet weirs remains uncommon in modern tray design. The loss of liquid on the tray also leads to loss of tray efficiency and can result in dramatic failure of the column to perform any separation. FRI information should be developed to allow the designer to understand tray design features or conditions which are prone to “blowing”.

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DST-4 3-Pass Trays Expected Benefit toMembers:

Traditional Research Idea

Improved design correlations would permit more accurate predictions of column capacity and efficiency. Multi-pass trays could be specified in lieu of two-pass trays to reduce column diameter or tray spacing for a given jet-flood and downcomer backup limit. Present Situation and Proposed Research: Multi-pass trays are typically specified for high liquid rate applications to reduce weir loadings and to mitigate the negative associated effects such as jet flooding, pressure drop, and downcomer backup. Design methods may be found in the open literature and in suppliers' know-how, but approaches are inconsistent. It is proposed that three-pass trays be tested in the 8-foot section of the low-pressure column. Tests would be performed using the iC4/nC4 system at 165 psia (the limit for the low-pressure column) as an example of a high liquid rate system where multi-pass trays would be considered. Data taken would include capacity and efficiency for the overall tray as well as for each panel to attempt to quantify the effects of varying L/V ratios. Prior to entering into the hardware design, a literature search will be conducted to assimilate the available philosophies and correlations dealing with the design of multi-pass trays. The literature search will also identify gaps in design approaches. Member companies will be surveyed to assess experiences (positive and negative) with multi-pass trays and to invite them to forward any design methods they feel appropriate. Proposed Internals and Test System:

Estimated Unit Time: Three weeks per tray design, six weeks’ total. Estimated Additional Costs (Beyond Unit Time): To achieve high loadings in the 8-foot section, it is necessary to complete portions of the current capital upgrade program.

Trays would be commercially fabricated, 1/2 inch hole diameter 11% sieve trays with 2 inch weir height. Two different three-pass tray designs would be tested - 1) a design based on equal flow path length; and, 2) a design based on equal bubbling area. All other parameters (weir height, hole size, fraction hole area, downcomer clearance, etc.) would remain the same for both designs.

Background and Discussion: Various models and rules of thumb for the design of multi-pass trays are available to the designer from suppliers and from the open literature. Designs have been constructed which have met with less than successful operation, to the point that some end users will not accept trays in excess of two flow passes. Conversely, many columns have been designed and successfully operated using three, four, or more liquid passes. Why many columns have exhibited good operation while some columns have not may be largely attributed to the designer's approach. The proposed program would investigate the two major philosophies of multi-pass tray design, equal bubbling area or equal flow path length, to determine the advantages and disadvantages of each in terms of both capacity and efficiency.

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DST-6 System Limit on Trays Expected Benefit toMembers: With the rise in popularity of high-capacity trays, the system limit is often approached. The tray designer needs additional information on this limit and factors that affect it on trays. Present Situation and Proposed Research: FRI only has a handful of data on system limit in trays with downcomers. Recent changes to FRI’s system limit correlation produced prediction differences as high as 30-50% for sieve trays. The current tiny system limit data bank provides an insufficient basis to confirm or deny even such large differences in prediction. There is an absence of data showing how system limit on downcomer trays is affected by liquid rate, hole diameter, and horizontal blowing such as that experienced on several high-capacity trays. There is a debate going on whether the system limit is a function of the superficial or free area in a tray with downcomers - a very large difference! Again, the existing data bank is too tiny to provide an answer. Simulator work is proposed using air-Isopar™ at several tray spacings starting at 36 inches, increasing the tray spacing until capacity no longer increases. Tests are proposed with sieve trays of different hole sizes, hole areas, downcomer top areas, one valve tray, and one proprietary tray (already tested by FRI) with horizontal vapor flow. Proposed Internals and Test System: Traditional Research Idea

Estimated Unit Time: Four operating weeks for each tray, total eight weeks. Estimated Additional Costs (Beyond Unit Time): Simulator work will likely be contracted out ($50,000).

Two tray designs will subsequently be developed and tested at 36 or 48-inch tray spacing in the high-pressure column with systems over the entire pressure range.

Background and Discussion: The proposed program will give insight into the nature of system limit on downcomer trays and into the factors that affect the limit. It will give engineers an idea as to when increasing tray spacing can be used for tower debottlenecking. It will also provide an answer on when a high capacity tray can provide capacities that exceed the system limits in conventional trays. It may also point out regions where use of some high capacity trays may be of limited benefit.

PROSPECTUS

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DST-13 Dynamic Model Verification of Tray Performance Expected Benefit toMembers:

Traditional Research Idea

Dynamic column simulation is used to verify control system strategy and is the heart of a training simulator for operators. Improvements in these models would assist in optimizing control strategy and operator training - before the column is actually started up. Present Situation and Proposed Research: Simplified tray hold-up models are used by dynamic simulations to ensure rapid calculation, since the model needs to run faster than real time in order to be useful. FRI could obtain detailed time dependent composition and holdup data for a trayed column during a step change. This could then be used by the major dynamic simulation vendors to improve their internal models. The membership would also learn how good the initial model predictions were. Proposed Internals and Test System: Standard valve or sieve trays. Estimated Unit Time: Four weeks. Estimated Additional Costs (Beyond Unit Time): None. Background and Discussion: Dynamic modeling use is becoming more widespread and frequent. Users need to be assured that the dynamic simulation results truly match reality. And with computers becoming more powerful, more complex models can be used within the dynamic simulation while still allowing the simulation to run at least twice real-time speed.

PROSPECTUS

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