AlChE Equipment Testing Procedure Continuous Direct-Heat Rotary Dryers A Guide to Performance Evaluation Third Edition AlChE Equipment Testing Procedure Continuous Direct-Heat Rotary Dryers A Guide to Performance Evaluation Third Edition Prepared by the Equipment Testing Procedures Committee AIChE" A JOHN WILEY & SONS, INC., PUBLICATION Cover and book design by Lois Anne DeLong Copyright 2006 by American Institute of Chemical Engineers All rights reserved Published by John Wiley & Sons, Inc., Hoboken, New Jersey Published simultaneously in Canada No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, scanning, or otherwise, except as permitted under Section 107 or 108of the 1976 United States Copyright Act, without either the prior written permission of the Publisher, or authorization through payment of the appropriate percopy fee to the Copyright Clearance Center, Inc., 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any other commercial damages, including but not limited to special, incidental, consequential, or other damages For general information on our other products and services or for technical support, please contact our Customer Care Department within the United States at (800) 762-2974, outside the United States at (3 17) 572-3993 or fax (317) 5724002 Wiley also publishes its books in a variety of electronic formats Some content that appears in print may not be available in electronic formats For more information about Wiley products, visit our web site at www.wiley.com Libmy of Congress C~aloging-in-~blication Data is available ISBN-I3 978-0-471-78493-7 ISBN-I0 0-471-78493-1 Printed in the United States ofAmerica 10987654321 Continuous Direct-Heat Rotary Dryers Table of Contents 100.0 PURPOSE AND SCOPE 101.0Purpose 102.0 Scope 1 200.0 DEFINITIONS AND DESCRIPTION OF TERMS 20 1.0 Dryer Description 202.0 Description of Terms 300.0 TEST PLANNING 301.0Conditions 302.0 Dryer Material and Heat Balances 303.0 Test Prepaidan 9 16 400.0 INSTRUMENTS AND METHODS OF MEASUREMENT 17 40 1.0 Gas Temperature and Humidity 17 402.0 GasFlow 18 403.0 Material Temperature and Moisture Content 19 404.0 Material Flow and Cylinder Fillage 20 405.0 Radiation and Convection Heat Losses 22 406.0 Miscellaneous Measurements 23 500.0 TEST PROCEDURE 501.0 Procedures 25 25 600.0 COMPUTATION OF RESULTS 60 1.0 Material Balances 602.0 Gas Flow and Heater Output 603.0 Heat Balance and Gas Flow 604.0 Cylinder Fillage and Time-of-Passage 605.0 Dryer Power Consumption 26 26 27 28 28 30 700.0 INTERPRETATION OF RESULTS 70 1.0 Material, Moisture and Energy Balances 702.0 Volumetric Heat Transfer Performance 31 31 31 800.0 APPENDIX 80 1.0 Nomenclature 802.0 Sample Problem-SI Units 803.0 Sample Problem-English Units 804.0 General References 34 34 35 38 42 AlChE Equipment Testing Procedure List of Figures Figure 1: Counter-Flow Rotary Dryer Figure Rotary Dryer with Dust Collection System Figure 3: Drying Rate as a Function of Drying Time Figure 4: Rotary Dryer Test Data Sheet Figure 5: Data Measuring Points for Material and Energy Balances 13 14 26 Continuous Direct-Heat Rotary Dryers: A Guide to Performance Evaluation, Third Edition by Equipment Testing Procedures Committee Copyright © 2006 American Institute of Chemical Engineers Continuous Direct-Heat Rotary Dryers 100.0 PURPOSE AND SCOPE 101.O Purpose The purpose of this procedure is to suggest a method for conducting performance tests on continuous direct-heat rotary dryers 101.2 Reasons for conducting performance tests on commercial-size dryers may be: To measure the performance of the dryer under typical operating conditions; To determine optimum dryer capacity under existing operating conditions; To study alternative operating conditions for increasing dryer capacity and performance; To provide a record for future troubleshooting; To gather data for design of new dryers of different capacities, or dryers for similar products; To study specific dryer characteristics that may affect product quality, e.g., speed, slope, rotation, temperature profile, active loading, and calculated factors, such as the volumetric heat transfer coefficient; To determine a desirable operating range for routine control of the dryer and the thermal sensitivity of materials; To determine the optimum operating conditions for cost-effectiveness, fuel conservation, and minimum environmental impact, and To study the specific drying characteristics that determine product quality, e.g residence time, temperature profile, etc 101.3 Although this procedure could be used as a guide for designing tests to demonstrate dryer capacity under manufacturers’ performance guarantee conditions, it is not intended for this purpose, nor is this procedure adequate to serve as a basis for a performance guarantee For example: 1) This procedure does not set limits or acceptable deviations between pilot plant test results or manufacturers’ predictions and commercial results 2) It does not address material handling questions, nor feed properties and uniformity other than those of feed rate and moisture content 3) It does not set standards for fabrication quality and mechanical performance 4) Moreover, for any specific product, there may be particular temperature or moisture measurements, sampling techniques, and quality requirements other than dryness which should be included in performance specifications AlChE Equipment Testing Procedure 102.0 Scope This procedure applies to continuous direct-heat rotary dryers (See Section 202.8) in which a wet material being dried is conveyed by slope and rotation of an essentially horizontal cylinder Material movement is also either slightly enhanced or impeded by a stream of gas flowing through the cylinder, depending on the material and the flow direction of the gas stream The gas stream is usually the sole external source of thermal energy for material heating and liquid vaporization, and is also the carrier gas for removing evolved vapors from the cylinder Gas flow direction may be either co-current with, or counter-current to, material flow This procedure excludes situations in which fuel enters with the material and is burned, i.e., the de-oiling of metal chips, turnings, and borings It also excludes cooling operations and special situations, such as drying of sugars and other materials that may change chemical characteristics on being heated Schematically, the flows are as indicated in Figure 102.2 This procedure is primarily intended for continuous direct-heat rotary dryers in which both gas and material flow are end-to-end of the dryer cylinder, and in which heat is transferred primarily by convection from hot gases to wet materials 102.3 This procedure is not intended for any form of indirect-heat rotary dryers, or other types of dryers, such as flash dryers, freeze dryers, vacuum pan dryers, paddle dryers, or high temperature calciners and kilns, where radiation is the primary heat transfer mode Continuous Direct-Heat Rotary Dryers: A Guide to Performance Evaluation, Third Edition by Equipment Testing Procedures Committee Copyright © 2006 American Institute of Chemical Engineers Continuous Direct-Heat Rotary Dryers 200.0 DEFINITIONS AND DESCRIPTIONS OF TERMS 201.O Dryer Description (see Figure 1) Courtesy of Swenson Technology, Inc Figure 1: Counter-Flow Rotary Dryer 201.1 A continuous direct-heat rotary dryer consists of a rotating cylinder, which may be slightly inclined to the horizontal to promote or retard material flow The inside of the cylinder may be fitted with material conveying flights and lifting flights of various forms designed to lift and shower the material through the gas stream as both material and gases move through the cylinder, thus enhancing intimate gas-solids contact The ends of the rotating cylinder are joined to stationary breechings that connect to the gas supply and exit gas ducts, the material feed, and product conveyors The annular clearances between the ends of the rotating cylinder and stationary breechings are enclosed by fabric, friction, or labyrinth rotary seals in order to minimize the effect of air leakage on the operating conditions Figure is an illustration of a typical continuous direct-heat rotary dryer A sketch of a typical dryer system is shown in Figure AlChE Equipment Testing Procedure I I Water I I I Wet Feed Exit Gases \ I I External Combustion Chamber Steam Dryer Feeder i -Recycle II I Y I W + y r Air Condensate Product Figure 2: Rotary Dryer with Dust Collection System 201.2 Feed material is introduced into one end of the rotating dryer cylinder through a feed screw or chute This screw or chute is supported in the feed breeching, and projects a short distance into the cylinder Other feed devices include vibrating feeder and progressive cavity pumps At the feed point, the cylinder is fitted with a retaining dam and conveying flights to move the wet product into the active cylinder, and to prevent back spillage into the feed breeching Material is conveyed through the cylinder as a consequence of feed material head and cylinder slope and rotation, aided or retarded by gas flow as the lifting flights repeatedly shower material through the gas stream At the other end Continuous Direct-Heat Rotary Dryers of the rotating cylinder, the dry material flows into the discharge-end stationary breeching containing the product conveyor, either by flowing out the end of the cylinder or through slots around its periphery 201.3 The gas stream may be heated directly or indirectly by any convenient means before entering the dryer cylinder This gas stream provides al the thermal energy needed to: heat the material and the moisture to be removed (moisture is usually water used in the procedure), heat and evaporate the moisture, and heat the vapors to exhaust temperature; compensate for conduction, convection, and radiation heat losses from the cylinder, breechings, and ductwork, all of which can be insulated or not insulated; leave the cylinder at a sufficiently high temperature to prevent vapor condensation in the exit ducts, and in the downstream off-gas treatment equipment 201.4 After leaving the dryer cylinder, al gas and vapor from drying usually passes through dust recovery and exhaust gas treatment equipment before being released to the atmosphere The most common forms of separation equipment employed on continuous direct-heat rotary dryers are dry-type cyclones for the primary recovery of dust, followed by dry fabric filters or wet scrubbers Modern regulatory requirements encompass volatile gas components as well as particulate matter, NOx quantities, and the like, in off-gases, and may dictate further processing and treatment 201.5 Fans are used to direct the gas stream flow through the heater, dryer cylinder, and off-gas treatment equipment The simplest fan arrangement, used on dryers with low pressure drop air heaters, is a single, induced-draft exhaust fan, located downstream from the exit gas treatment system so it will operate on dust free gas This one fan must have static pressure capability to accommodate the pressure drop through the entire system, including heat source, dryer, breechings, ductwork, dust removal, and other treatment equipment Alternatively, when the pressure drop through an inlet gas filter, gas heater, and gas inlet duct exceeds a certain level-125-250 Pa, 0.5-3.0 in of water, a second, forced draft fan may be installed upstream from the filter or heater to overcome the drop In this manner, by balancing the two fans, the pressure inside the cylinder at the rotating seals can be maintained at a level close to, but slightly below, atmospheric pressure, regardless of the pressure drop through the inlet system This will ensure that no process vapors leak to the atmosphere Secondary fans are generally not used in order to conserve cost and reduce complexity of operation AlChE Equipment Testing Procedure For a first approximation of temperature driving force, in counterflow operation, temperature differences at each end are determined by measuring the wet feed temperature and the exit gas temperature at the feed end, and the incoming gas temperature and dry product outlet temperature at the product discharge end: Wet feed end: 343-303= 40K Dry product end: 423-393 = 30K Temperature difference: 35K, average Therefore: But, measurements from the experiment indicate: = 594 kW (See Section 802.4) Q(2) = 1kW (See Section 802.4) Q(3) = 28 kW (See Section 802.4) Q(4) = kW (See Section 802.4) Q(5) = 883 kW (See Section 802.4) Q(6) e Q = 1,507kW (See Section 802.4) And Q(t)= 1,666 kW between 423K and 343K, based on air flow Due to wide variance between the two values of the following refinements can be made to narrow the discrepancy Assume: Fraction of energy to evaporation alone: 883/ 1,666~0.53 Fraction of energy to sensible heat and losses: 783/ , 6 ~0.47 With respect to the total air temperature drop of 80K (423K - 343 K), assume: 0.47 x 80K= 38K, to sensible heat and losses 0.53 x 80K=42K, to evaporation 32 Continuous Direct-Heat Rotary Dryers Evaporation occurs first, at the wet end; then the material is heated to the exit product temperature Thus, the counter-current flowing gas reaching the wet zone approaches 423 - 38 = 385K (1 12" C) At an absolute humidity of 0.015 kg/kg, the wet bulb temperature is 39" C = 312K, and most of the evaporation may be assumed to occur at a material temperature close to the wet bulb temperature; therefore: 423 - 393 = 30K Dry End: Begin Heating: 385 - 312 = 73K Log mean temperature difference for heating = 48K End Evaporation: 385 - 312 =73K 343 - 303 = 40K Wet End: LMTD for evaporation = 55K Use: Average temperature difference = 51K NOTE: Other factors affect heat transfer The expression for volumetric heat transfer con- tains terms for gas mass velocity cylinder diameter, and a constant, yet all the factors which have heretofore been discussed, such as volumetric loading, feed moisture, feed rate, etc not appear in the volumetric heat transfer coefficient equation It is clear that all of these factors affect heat transfer Another viewpoint is that seen from the solids side As solids shower through the rotating dryer, they provide a heat transfer area Without solids in the dryer, the volumetric heat transfer coefficient is meaningless Thus the total solids loading affects heat transfer, and the more solids which can be showered in the gas stream, the higher the heat transfer area Similarly, increasing the amount of solids, will also increase the total heat load 702.2 The calculated volumetric heat transfer attainment, combined with other measured factors, indicates this dryer probably is operating fairly close to its maximum capacity unless the inlet gas temperature can be increased without damaging the product Dust lost to the collection system, and thus not totally dried, is already approaching 10% of the feed material A further increase in gas velocity through the cylinder would provide more energy for drying without increasing the inlet gas temperature, but the dust loss might soon approach a high fraction of the total material This might not be a problem if the fines are dry and can be combined with dryer discharge In fact, some rotary dryers are designed to operate with 100% product entrainment This would be a point to be considered in the specific installation being tested Also, cylinder fillage at 17.1% is certainly adequate to fill the showering flights and enable them to function at optimum efficiency And, as shown in Appendix 800.0, most of the fillage and time-of-passage are caused by the retarding effect of gas flow on material flow through the cylinder Again, if gas flow were increased, loading soon would exceed a quantity that could be effectively lifted and showered, and non-uniform drying and material holdup could be experienced 33 Continuous Direct-Heat Rotary Dryers: A Guide to Performance Evaluation, Third Edition by Equipment Testing Procedures Committee Copyright © 2006 American Institute of Chemical Engineers AlChE Equipment Testing Procedure 800.0 APPENDIX 801.O Nomenclature Material active angle of re ose, radians (from horizontal) *~, Particle size factor, ( D P ) - ~dimensionless Steam condensate flash off, kg/s Total condensate, Cw + Cf, kg/s Weight of steam condensate, kg/s Gas humid heat, kJ/(kg K) Solids specific heat, kJ/(kg K) Cylinder riding ring outside diameter, m Average solids particle diameter, pm Cylinder inside diameter, m Evaporation from material balance, kg/s Evaporation from humidity balance, kg/s Product mass flow rate, kg/(s m Gas (air) mass flow rate, kg/(s m ) Hydrogen in the fuel burned, kg/s Initial, dry basis gas humidity kg/kg Dry basis humidity leaving cylinder, kg/kg Dry basis humidity leaving dust recovery, kg/kg Liquid water enthalpy at P(s) and T(s), kJ/kg Liquid water enthalpy at 373K, 101.3 @a, kJ/kg Liquid content enthalpy at t(l), kJ/kg Liquid content enthalpy at t(2), kJ/kg Liquid content enthalpy at t(3), kJ/kg Steam latent heat at P(s) and T(s),kJ/kg Steam latent heat at 373K, 101.3 kPa, kJ/kg Vapor enthalpy at T(5), kJ/kg Dryer cylinder length, m Total material feed rate, kg/s Dryer feed solids rate, kg/s Total dryer product rate (from cylinder), kg/s Dryer product solids rate (from cylinder), kg/s Total recovered dust rate, kg/s Recovered dust solids rate, k /s Cylinder rotational speed, s- ‘3 K Heater steam pressure, kPa Power required to turn cylinder, kW Dryer cylinder slope, solids flow direction, radians Energy consumed in (x) process, kW Dryer cylinder slope in solids flow direction, m/m Gas (air) temperature before heater, K Gas (air) temperature leaving heater, K 34 Continuous Direct-Heat Rotary Dryers Gas (air) temperature before cylinder, K Gas (air) temperature leaving cylinder, K Gas (air) temperature leaving dust recovery, K Heater steam temperature, K M(1) temperature, K M(2) temperature, K M(3) temperature, K Gas (air) flow into heater, m 3/s Gas (air) flow leaving dust recovery, m3/s V(1) specific humid volume at T(l), m3/kg of dry gas V(5) specific humid volume at T(5), m3/kg of dry gas Holdup plus dryer rotating weight, kg Holdup (active wt of material) rotating weight, kg Feed, wet-basis moisture content, kg/kg Product, wet-basis moisture content, kg/kg Dust, wet-basis moisture content, kg/kg Distance between centerline of the cylinder and the center of gravity of the material bed in a dryer without lifting flights, m Time of solids passage through dryer c linder, s Solids (wet and dry) bulk density, kg/m 802.0 Sample Problem-SI Units Counter-current, continuous direct-heat rotary dryer; forced-draft inlet fan; inlet air filter; steam-coil air heater; dry, fabric, bag-type dust recovery system; induced-draft supply fan; 60 kW cylinder drive motor; feed-end conveyor flights for 16m, 0.40 m high, 1.O in length, 24 per circle, 16 sets = 3.35m = 3.95m L = 18.30m N = 0.042s-1 S = 0.026 m/m (W-W) = 1,300kg d D 802.1 Measured Test Data CW CS 31) M(2) M(3) X(l) X(2) = 1.25 kg/s = 2.26 kJ/(kg K) = 250 pm = 3.592 kg/s = 2.924 kg/s = 0.3 15 kg/s = 0.100 kg/kg = 0.001 kg/kg 35 AlChE Equipment Testing Procedure X(3) T(l) T(2) T(3) T(5) t(1) t(2) t(3) V(l) V(5) P(s) PW p(2) = 0.010 kg/kg = 303K = 428K = 423K = 343K = 303K = 393K = 343K = 17.79 m3/s at 303K and 296K (wet bulb) = 22.42 m3/s at 343K and 31 1K (wet bulb) = 1,136kPa = 45.0 kW = 640 kg/m3 802.2 Material Balances Mod) = 3.592 x (1.0- 0.100) = 3.233 kg/s M(2d) = 2.924 x (1.0-0.001) = 2.921 kg/s M(3d) = 0.315 x (1.0-0.010) = 0.312 kg/s Mod) - M(2d) - M(3d) = 3.233 - 2.921 - 0.312 = kg/s = (3.592 x 0.1) - (2.924 x 0.001) - (0.315 x 0.01) E(l) = 0.3592 - 0.0029 - 0.003 = 0.3531 kg/s = 303K (dry bulb), 296K (wet bulb) T(1) = 0.0 15 k /kg (see psychrometric chart) H(l) = 0.880 m /kg (see psychrometric chart) v( 1) = 343K (dry bulb), 1K (wet bulb) T(5) = 0.030 kg/kg (see psychrometric chart) H(S) = 1.020 m3/kg (see psychrometric chart) v(5) = (22.42/ 1.020) x (0.030 - 0.0 15) E(2) = 0.3297 kg/s Note-Dryer in-leakage: (22.42/ 1.020) - (17.79/0.880) = 1.98-20.22 = 1.76 kg/s = 1.55 m3/s at 0.880 m3/kg 802.3 Gas Flow and Heater Output T(l) = 303K T(2) = 428K = 1.0 + 1.87 x H(l) = 1.03 kJ/(kg K) Ca = (1 7.79/0.880) x 1.03 (428 - 303) Q(1) = 2,603kW = 1,993 kJ/kg at 1,136 kPa hfg(l) 36 Continuous Direct-Heat Rotary Dryers ct CW hdl) hA2) hfg(2) Cf/Ct ct = 2,603/(1,993 x 0.95) = 1.37 kg/s (based on air flow and temperature) = 1.25 kg/s = 789 kJ/kg =419 kJ/kg ~ , 6kJ/ kg = (789 - 419)/2,256 = 0.164 = 1.25/(1.0 - 0.164) = 1.50 kg/s (based on steam condensate flow) 802.4 Heat Balance and Gas Flow = 126 kJ/kg at 303K hA3) = 502 kJ/kg at 393K hA4) = 293 kJ/kg at 343K hA5) = 2,626 Kj/kg at 343K = 2.924 x (1.O - 0.00 1) x 2.26 x (393 - 303) Q(3) = 2.924 x 0.001 x (502 - 126) = 0.3 15 x (1.O- 0.0 10)x 2.26 x (343 -303) Q(4) = 0.3 15 x 0.010 x (293 - 126) Q(5) Q(6) = 0.353 x (2,626 - 126) = 1.76 x 1.03 x (343 - 303) Q(7) bg) 2Q (9) (10) (13) = 1,579kW Q(8) = 1,579 x (0.1/0.9) (assume 10% of total energy) at) = (17.79/0.880) x 1.03 x (423 -343) = 1666 kW (15) 802.5 Cylinder Fillage and Time-of-Passage B Noe9 G/F = 5/(250t: = 0.32 (194 = (0.042) = 0.058 = (1 7.79 x 0.88)/2.294 = 6.8 e = (0.35 x 18.3/(0.026 x 3.35 x 0.058)) + (118 x 0.32 x 18.3 x 6.8) = 1,268 + 4,699 = 5967 s W = 5,967 x 2.924 = 17,448 kg (19) Cylinder fillage = 17,448/640 = 27.26 rn3 Cylinder fillage (%) = 27.26 x 100/((3.35)2x 0.785 x 18.3) 16.91'/o 37 AlChE Equipment Testing Procedure 802.6 Cylinder Drive Power Consumption PW = 0.042 x ((34.3x 3.35 x 17,448) + (1.39 x 3.95 x 68,748+ (0.73 x 68,748))/2,234 = 45.7kw (22) 803.0 Sample Problem-English Units Same as example in Section 802.0, but recalculated in the English unit system d D L N S (W-W) = 11.0 ft = 13.0 ft = 60.0 ft = 2.5 rev/min = 5/16 in/ft = 113,600 lbs 803.1 Measured Test Data = 10,000 lbs/ hr = 0.45 Btu/lb" F = 0.0 10 in = 28,500 lb/hr = 23,200 lb/hr = 2,500 lb/hr = 0.100 lb/lb = 0.001 lb/lb = 0.010 lb/lb = 86" F = 311°F = 302" F = 158" F = 86" F = 248" F = 158" F = 37,700 cu.ft./min at 86" F, 73" F (wet bulb) = 47,500 cu.ft./min at 158" F, 101" F (wet bulb) = 150 psig = 60 hp = 40 lb/cu.ft 803.2 Material Balances M(l4 M(2d) = 28,500 x (1.0-0.100) = 25,650 lb/hr = 23,200 x (1.0 - 0.001) = 23,177 lb/hr 38 Continuous Direct-Heat Rotary Dryers = 2,500 x (1.0 - 0.010) = 2,475 lb/hr M(34 M(1d) - M(2d) - M(3d) = 25,650 - 23,177 - 2,475 = -2 = (28,500 x 0.100) - (23,200 x 0.001)-(2,500 x 0.0 10) E(1) = 2,850 - 23 - 25 = 2,802 lb/hr = 86" F (dry bulb), 73" F (wet bulb) T(1) = 0.0 15 lb/lb (see psychrometric chart) H(1) = 14.1 ft3/lb (see psychrometric chart) V(1) ~ 8F " (dry bulb), 101" F (wet bulb) T(5) = 0.03 lb/lb (see psychrometric chart) H(5) = 16.3 ft3/lb (see psychrometric chart) V(5) = (47,500 x 60 mid16.3) x (0.030 - 0.0 15) E(2) = 2,623 lb/hr (5) N o e D r y e r in leakage: (47,500 ~ 016.3) / - (37,700 x 60/ 14.1) -1 75,000- 160,500 = 14,500 lbs/hr = 3,389 ft3/min at 14.1 ft3/lb 803.3 Gas Flow and Heater Output = 86" F = 311°F = 0.24 + 0.45 x H(l) = 0.246 BtuAb" F = (37,700 x 60/ 14.1) x 0.246 x (31 - 86) = 8,880,000 Btu/hr (= 2,602 kw) = 857 Btu/lb at 150 psig = 8,880,000/(857 x 0.95) = 10,900 lb/hr (based on air flow and temperature) = 1.37 kg/s = 10,000 lb/hr = 339 Btu/lb = 180 Btu/lb = 970 Btu/lb = (339 - 180)/970 = 0.164 = 1O,OOO/( 1.O - 0.1640) = 1,961 lb/hr (based on steam condensate flow) = 151 kg/s 39 AlChE Equipment Testing Procedure 803.4 Heat Balance and Gas Flow = 54 Btu/lb at 86' F = 16 Btu/lb at 248" F = 126 Btu/lb at 158' F = 1,129 Btu/lb at 158' F = 23,200 x (1.0- 0.001) x 0.54 x (248-86) = 23,200 x 0.001 x (216 - 54) Btu/hr = 2,500 x (1 O - 0.0 10) x 0.54 x (1 58 - 86) Btu/hr = 2,500 x 0.010 x (126-54) Btu/hr = 2,802 x (1,129 - 54) Btu/hr = 14,500 x 0.246 x (158 - 86) Btu/hr $Q (9) (10) (1 1) (12) (13) (14) = 5,398,267BTU / hr = 5,398,267 x (0.1/0.9) Btu/hr $Q = 5,998,074BTU/ hr = (37,700 x 60/14.1) x 0.246 x (302 - 158) = 5,682,914 Btu/hr Note: Q(t) >0.9xQ 803.5 Dryer Fillage and Time-of Passage e B DP No.9 G/F = (0.23 L/(S x N0a9 x d)) + (0.6 x B x L x G/F) = = 0.0 10 x 25.4 x 1,000 = 250mp = 5/ (25q0'",: 32 = (2.5)o- = = 37,700 x 60/( 14.1 x 23,200) = 6.9 e = (0.23 x 60 x 12/(0.313 x 2.28 x 11.0)) + (0.6 x 0.32 x 60 x 6.9) = 21 + 79 = 100 W = 23,200 x (100/60) = 38,667 lb Volume fillage: 38,667/40 = 967 ft3 Percent fillage: 967 x loo/(( 1)2 x 0.785 x 60) = 16.96% 40 Continuous Direct-Heat Rotary Dryers 803.6 Cylinder Drive Power Consumption BhP = N x ((4.75 x d x w)+(0.1925 D x W) + (0.33 x W))/lOO,OOO = 2.5 ((4.75 x 11.0 x 38,667) + (0.1925 x 13.0 x 152,267) + (0.33 x 152,267))/ 100,000 = 61.3 Bhp Note: The relationships describing Time-of-Passage and Brake Horsepower required are given in English units in Perry’s Chemical Engineers’ Handbook, 5th Edition, pp 20-35 and 2-40, respectively See Reference 804.7 803.7 Recalculation of Volumetric Heat Transfer Performance in English Units (see Section 702.0) a x (G)0-67/d = Btu/(h, ft3, O F) where 0.50