RSCE-SOMCHE 2008 385 Edited by Daud et al.

SPRAY DRIER CHEMICAL AND MECHANICAL DESIGN VIA SPREADSHEET – A STUDY ON THE

INSTANT COFFEE ARABICA POWDER PRODUCTION PROCESS

Abu Bakr Saber Abu Bakr Saleh1, Zulkifli Abdul Rashid1*, Azil Bahari Alias1, Naim Adzha Muhammad2, Hazlina H1, Mohd Jindra Aris1, Mohanad El-Harbawi3

1Faculty of Chemical Engineering, University of Technology MARA, 40450 Shah Alam Selangor

2 Nestle Manufacturing (M) Sdn Bhd, Shah Alam 3 University Technology Petronas, Tronoh, Perak

* Correspondence author: Tel: +603-55436341; Tel: 0123940702 Email: zulkif02@salam.uitm.edu.my

Email: zulmas06@yahoo.com.my

Keywords: Spray drier, Spreadsheet, Coffea arabica and Drying

ABSTRACT

This paper presents the application of spreadsheet towards the design of a spray drying equipment, specifically spray drying chamber equipped with atomizing disk. But, before the design of drying chamber can be commenced, several tasks must be accomplished, and these include material and energy balances. Due to the characteristics of spreadsheet that provide instant results with calculation iterations, high degree of accuracy and easy to use programming, it is often used in aiding the person to carry out many calculations especially when the design of unit operation is to be carried out. The instant coffee powder production is utilized to describe the spray drying chamber design through the use of spreadsheet. It is undeniable that once the parameters, working and design equations have been established, one will find spreadsheet as a method that promises very easy application to manipulate all of the working variables so that design, reiterations of calculations, scale up of the unit operation, can be made or even be adjusted to meet the design requirement appropriately.

INTRODUCTION

In engineering, the working personnel cannot avoid of being encounter with design. In chemical and process engineering one will eventually involved with

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the design of process equipment or unit operation, is it the famous distillation column, chemical reactor and others. And the person who’s in charge with the design will have at least three alternatives to be selected, he or she can use manual hand calculation, specially designed commercial software package or spreadsheet programmer like Microsoft Excel. By intuition, among these three, spreadsheet offered the best option to be chosen of, it has the characteristic of manual hand calculation of being cost effective and as quick as to that of commercial packages in solving the design calculation iterations, not to mention other advantages such as escaping the license fee, time required to learn the new software packages and complication to reiterate the calculations.

Microsoft Excel has been widely used today as the mathematical calculation solver by its root finding function. It is a software package that comes together with Microsoft Office developed by the world leading edge computer company which is the Microsoft ® Corporation (Bloch, 2000; Liengme, 1997). It has been proved useful to aid most of the engineering calculation which most of the times contains fixed variables (i.e. mass production rate) to be adjusted with working variables (i.e. input mass flow rate, steam requirement) which in nature pose difficulty and time consuming in finding them because each of the working variable are dependent to each other and they must be substituted into the equations to get the desired design values. Figure 1 showed a brief configuration of spray drying chamber (parallel air and product flow) equipped with disk atomizer from 2D and 3D views.

FIGURE 1: Typical spray drying chamber (parallel air and product flow) equipped with disk atomizer from 2D and 3D views

SPREADSHEET CALCULATION PROCEDURE

Coffee is the well-known beverage consumed by almost all of people over the world especially during breakfast. To produce coffee drinks that can be prepared simply by dissolving all the coffee mass in short time requires that the coffee

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soluble be extracted from the green coffee beans which were roasted in the first place, extracted for its soluble and concentrated for the resulting solution, then only dried using industrial drying system, and the famous always calls for spray drying system to produce what we know about coffee today as instant coffee powder. Three types of coffee beans have been identified, the famous Robusta bean, bitter Arabica bean and the least produced Liberica beans. In (Sivets, Coffee Processing Technology, volume two) Green coffee beans on dry basis consists of the dominant carbohydrate components that accounts for about 60 percent of its total mass which mainly includes reducing sugars, Sucrose, Pectins, Starch, Hemi-Celluloses and lignins leaving the rest such as oil, protein, ash, non volatile acids (Oxalic, Maleic Citric acid), trigonelline and the caffeine, existed in small proportions respectively. And often in coffee soluble extraction, the soluble, extractable part is the carbohydrate components, which can be treated as single solid component so that mass balance can be carried out without any hassle associated with specifying each component. For the simplicity purposes in this paper, all of these carbohydrates components that constitute the coffee soluble will be treated as a single component that dissolve in water to be in coffee solution state.

The calculation starts out with mass balances of instant coffee powder whereby the coffee mixture is fed to the spray drying chamber via the connecting pipe rotated about its axis located at the center of the drying chamber. At the end of the pipe is the disk atomizer which is used to disperse the coffee mixture horizontally and as the coffee mixture travel along the diameter of the chamber it will be contacted with hot drying air where eventually the air will be sucked out by outlet pipe by the use of air compressor while the dried instant coffee powder particles will be collected at the bottom of the chamber using either tote bin or other appropriate equipment.. The fixed parameter is based on production rate of 860 kg/hr of instant coffee powder from mixture of coffee powder at total concentration of 50% by mass/ weight. As well as moisture content of instant coffee powder set at 2% by weight. There are no specific chemical reactions in this section; it only involves drying process about the coffee mixture. In general from the material balance, it will provide data on mass flow rate of coffee mixture required that to be fed into the drying chamber and moisture vaporization rate. While for energy balances, it will provide parameters such as outlet temperature of drying air and heat energy required to heat up the drying air at the specified temperature so that the desired instant coffee production specification can be met. The overall calculation presented here is based on the flowchart in Figure 2.

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FIGURE 2 Spray drier design calculation procedures

Mass Balance of Coffee Extract The mass balance for coffee soluble in the mixture is based on the simple basic mass balance equation, steady state condition without chemical reaction. The reduction of equation is as shown below:

General mass balance equation:

(1) Coffee Component balance equation:

(2) Component balance without chemical reaction, and no accumulation inside

system at steady state condition, equation is simplified to:

(3)

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Energy Balances The Vaporization Of Moisture From The Coffee Extract.

The energy balance equation to calculate the rate of steady heat transfer from hot drying air to the sprayed coffee extract is given as:

(4) The rate of energy transfer to the sprayed coffee extract calculated will then be

equated to the equation below to find the required hot air mass flow rate needed for drying:

Q = mair {Cp(air) + Hgi (Cp H2O(v)) (Tgi –Tgo) } (5)

With assumption relative humidity of inlet hot air stream is taken to be 0%

(dry). As for the calculation of the outlet exhaust air temperature , the number of transfer unit ( NTU ) of spray drier is utilized, but the value of NTU must first be assumed ( it was found to be economical for spray drier to have NTU range from 1.0 to 2.5). Moisture Vaporization temperature (Tvap) inside the chamber is actually the wet bulb temperature of hot drying air at its specified Relative Humidity and this can be obtained using psychometric chart. If the value is beyond the limit of the chart, simple linear extrapolation is appropriate to find its value.

CHEMICAL DESIGN

In chemical design, there are several matters that must be taken into account before determination of chamber’s volume and dimension can be carried out. Two approach towards this , first is by calculation using heat and kinetic (centrifugal) energy transfer to sprayed coffee extract, the second is by determining the drying time profile of sprayed coffee extract, which mainly occur in constant drying rate (a period of which moisture vaporization is constant throughout the surface of coffee extract droplet until the coffee particle achieve reduction of its moisture content 60 % of its original moisture mass fraction value) and the other is drying in falling rate (a period where moisture vaporization from the coffee particle to the surrounding drying air begins to fall due to resistance provided by the particle wall as well as little moisture vapor pressure in the coffee particle until specific moisture content of coffee product is achieved). When sizing of the chamber took place, then only, ancillary equipment such as air distributor, inlet and outlet compressor can be determined or rated for its power consumption. But the first thing that must be taken into

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consideration to start the chemical design of spray drier is the Sauter mean diameter of the sprayed particle. As stated in (Filkova and Mujumdar 1995), the Sauter mean diameter corresponds to particle diameter with the same volume to surface ratio as the entire spray sample (or powder sample) and the associated equation to calculate it is as shown below:

D3,2 = 1.62 x10-3 . N(-0.53) . M(0.21) .(2r)(-0.39) (6)

This is the simplest equation that only requires three parameters to be specified,

revolution of the disk, (N), Mass Feed rate of the extract, (M) and atomizing disk diameter (r). This equation disregard many aspects of the coffee extract itself such as its apparent viscosity (which is greatly affected because coffee extract is considered to be non Newtonian Fluid and often regarded to be pseudo plastic in nature), vane height of atomizing disk, surface tension and atomizing disk’s number of vanes. Next, one must determine the maximum size of droplet to be attained during the spraying process, the simple equation as in (Perry’s Chemical Engineers handbook) state that maximum droplet diameter is three times to that of Sauter mean diameter.

Dmax = 3 D3,2 (7) Maximum droplet diameter is very important because it is considered to be

biggest diameter of droplet produced from atomizing disk at specific disk’s diameter and revolutions per minute (rpm) which in turn, requires the longest residence drying time in the drying chamber. In short, it will be used to determine the critical part of the drying chamber. To determine the moisture vaporization rate, equation in terms of heat transfer as in (Stanley E. Charm 1971) would be:

(8) Whilst the time required for droplet to be dried in constant rate period is

determined by difference in density between initial and critical condition (a state where constant vaporization of moisture end), the amount of moisture vaporize during the falling rate period is obtained by using the equation of (Stanley E. Charm 1971):

Amount of moisture vaporization (falling rate) = 12 Kf (∆T average) ∆Hv (Dp)2 Psolid (9) The chamber dimension has become critical at point of its diameter and vertical

height of cylindrical part (refer to diagram in spreadsheet- chemical design) this is because at this part, it is designed to give sufficient trajectory length and vertical length, and again, wet or partially dried coffee extract droplet is undesirable because it will stick to the chamber’s wall and this promotes

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corrosion of the wall and deliver poor instant coffee powder product formation. It may not be all, but some of the of chamber’s dimensioning can be calculated by using the particle trajectory X (Stanley E. Charm 1971), from the atomizing disk periphery; as shown below:

Particle trajectory, X = 1/c log (Vp.c. θ +1), Where c = (0.33 ρ air) and Dp ρ

solid (10) Vertical height of cylindrical (primary drying zone) – is determined by

multiplying the total drying time of droplet (constant and falling rate period) with the air velocity that traverses the chamber after been accelerated from air distributor flowing parallel to that of coffee extract droplet.

MECHANICAL DESIGN

In mechanical design, the concern is to rightfully choose the best suited yet economical material of construction for the drying chamber including the determination of chamber’s wall thickness, it must not be too thick due to the expensive cost of metal and must not be too thin because the chamber is subjected to hot air with and some imperfection of droplet drying which is wet, a great catalyst that promotes the chance of corrosion of metal by redox chemical reaction and subsequently degrading the produced instant coffee powder (must be minimized or eliminated to ensure longer useful life of the drying chamber). Therefore the most critical part is the one that exposed to higher temperature and incomplete dried wet coffee mixture; the air distributor wall and the chamber’s cylindrical part. The other part of chamber such as outlet exhaust gas pipe and conical wall section will mainly depend on critical part of chamber. The chamber’s internal pressure was determined as a difference between inlet pipe and out pipe pressure and is multiplied by specific safety factor (usually taken at 1.1 to 2.0).

CONCLUSION

It was found that the Microsoft Spreadsheet is a tool that proves to be useful when iteration of calculation is desired. It was quite easy to use with, highly precise and accurate in nature especially when involves in engineering calculations. However there is some limitation posed by spreadsheet, such as the lack of material properties, due to the nature of process substance parameter such as thermal conductivity, viscosity heat capacity which depends on temperature of the system, the value will change from each temperature and thus requires the person to reformulate a specific equation or interpolation over a range of data. This is what the costly commercial software packages have been offering but it is

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too expensive to own and renew the license, therefore it is only applicable for sophisticated processes such as refinery or petrochemical processes and when financial is not a major constraint. For a moderately designed system such as the one this paper, MS Spreadsheet has prove to be of worthy, and economically effective option by providing a cheaper alternative to the designer compared to costly commercial software.

REFERENCES

Arun S.Mujumdar, Iva Filkova, Industrial Spray Drying System, Wiley Publications, 3rd Ed.

Bloch, S. C (2000). Excel for Engineers and Scientists. New York: John Wiley Coulson & Richardson (1996), Mass Transfer and Separation Technology Principles,

Volume 2, 5th Ed. Liengme, B. V. (1997). A guide to Microsoft excels for scientists and engineers. London:

Arnold J.L.Heid, Maynard A. Joslyn (1963), Food Process Operations, Their Management,

Machines, Materials & Methods Vol.2, AVI Publishing. Michael Sivetz, Coffee Processing Technology, AVI publishing Company, Vol .1& Vol.

2. Noel de Nevers, (2006) Fluid Mechanics for Chemical Engineers, Mc Graw Hill

Publication 3rd Edition. R.K. Sinnott, Coulson & Richardson’s (2006), Chemical Engineering Series, Chemical

Engineering Design, 4th Ed, Vol.6. Ronald W. Rousseau, Elementary Principles of Chemical Processes, Wiley International

Publications, 3rd Ed. Stanley E. Charm (1971), The Fundamentals of Food Engineering, AVI Publishing Co. Solid Drying and Gas Solid Systems, Spray Dryer, Perry’s Chemical Engineers

Handbook (2005), Mc-Graw Hill Publication, 5th Ed. Yunus A. Cengel, Heat Transfer: A Practical Approach, Mc Graw Hill

Publication, 2nd Edition. Yunus A. Cengel & Robert H. Turner (2006), Fundamental of Thermal Fluid

Sciences, Mc Graw Hill Publication 2nd Edition.

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LIST OF NOMENCLATURE

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MASS AND ENERGY BALANCE SPREADSHEET OF SPRAY DRIERPROCESS FLOW DIAGRAM OF SPRAY DRYING CHAMBER WITH SECONDARY PRODUCT RECOVERY

DATA TO BE SET BY DESIGNER :

MASS BALANCE DATA:

Mass Production rate (instant Coffee Powder) 860 kg /hr Temperature 106.1164 ˚CTotal Soluble Concentration in Coffee Feed (Choose≥22.5% TC) 50 %TC, or 0.5 kg coffee /kg mixture Temperature 25 ˚C Exhaust Gas From Drying Chamber 17807.52 kg /hrDesired Moisture Percentage in coffee powder (final) 2 %moist,or 0.02 kg water /kg Feed 1720 kg/hr 16956.12 kg Air /hrEfficency of secondary recovery system (1%-100%)) 99 % or ( 0.99 ) 842.8 kg Moisture /hr

Coffee Mass 860 kg/hr 8.6 kg Coffee Mass /hrENERGY BALANCE DATA: Water 860 kg/hr

Wet Mixture Temperature ( Coffee feed ) 25 ˚C Hot Drying Air Mass Flow rate 16956.12 kg/hr Exhaust Gas from Bag FilterInlet Drying Air Temperature With 0%RH 240 ˚C Hot Drying Air Volume Flow rate 24403.21 m3/hr 17799.01 kg /hr

Spray Drier Number of Transfer Unit (NTU) (1 to 2.5) 2 16956.12 kg Air /hr

Air Temperature 240 ˚C 842.8 kg Moisture /hrSUBSEQUENT DATA GENERATION: Relative Humidity at 0% 0.086 kg Coffee Mass /hr

MASS BALANCE DATA:

Inlet Wet Coffee Mixture Mass Flow Rate 1720 kg/hrEntrained Coffee Powder Particles in Exit Stream 8.6 kg /hrRecoverable Coffee powder by Bagfilter at 99% effcy 8.514 kg /hrCoffee Powder loss in exit gas from bag filter 0.086 kg /hrInitial mass of coffee soluble in instant coffee powder 842.8 kg /hrActual mass of soluble before powder recovery 834.2 kg /hrMass of coffee powder produced before recovery 851.4 kg /hr at 2 %moisture levelNet mass production rate (instant coffee powder) 859.914 kg /hr at 2 %moisture levelNet mass production rate (instant coffee powder) 842.714 kg /hr coffee mass only Solid Mass fraction of water in coffee powder (final) 0.98 kg coffee /kgMass fraction of water in wet mixture 0.5 kg water /kg mixtureMass flow rate of water in the wet coffee mixture 860 kg/hr Vaporized water from coffee particles 842.8 kg/hr Recovered Coffee mass rateRemaining Moisture in Coffee Particles 17.2 kg/hr 8.514 kg/hr Net Instant Cofee Powder ProductionMass flowrate of exhaust gas from drying chamber 17807.52 kg/hr 859.914 kg /hrMass flowrate of exhaust gas from Bag Filter 17799.01 kg/hr

Mass production rate 851.4 kg/hr 842.714 kg coffee mass /hrMass flowrate of Drying Air Required 4.710034 kg/s = 16956.12 kg/hr Coffee mass 834.2 kg Coffee mass /hr 17.2 kg moisture /hrVolumetric Drying Air Flowrate 6.77867 m3/s = 24403.21 m3/hr Moisture 17.2 kg moisture /hr Velocity of Drying Air Before Entering Air Distributor 14.90591 m/sVelocity of Drying Air at Air Distributor Opening 0.853404 m/s

ENERGY BALANCE DATA:

Average Air inlet Outlet Temperature Difference 173.0582 ˚CDry solid Temperature 86.16129 ˚CWet bulb Temperature of Inlet Drying Air 85.16129 ˚CVaporization of Moisture Temperature 85.16129 ˚COutlet Air Gas Temperature 106.1164 ˚CEntalphy of Vaporization of water at wet Bulb Temperature range of (60˚C to 95˚C) 2294.365 kJ/kgPower (Heat Energy flow) Required for drying 644.7664 kW

FOR DESIGN:

Average Temperature difference of Coffee mixture and Inlet Drying Air 132.5 ˚CAverage Temperature difference of Air Wet Bulb and Inlet Drying Air 162.5806 ˚C

VARIOUS RELATED PROPERTIES AND CONSTANTS :

Heat Capacity of Coffee Solids 1.673 kJ/(kg˚C)Heat Capacity of moisture (vapor) at Wet bulb 1.983576037 kJ/(kg˚C)Heat Capacity of water (liquid) at 25˚C 4.184 kJ/(kg˚C)Heat Capacity of Air at Av in-out Temperature (60˚C to 250˚C) 1.022471124 kJ/(kg˚C)Density of Air at Average In-out Temperature (60˚C to 250˚C) 0.830265379 kg/m3Density of Air at inlet Temperature (60˚C to 250˚C) 0.694831579 kg/m3Density of Air at outlet Temperature (60˚C to 250˚C) 0.965699179 kg/m3Density of Water vapors at outlet temperature (60˚C to 240˚C) 4.383257262 kg/m3Thermal Conductivity of Dry Air Film at Droplet- Hot Air Temperature (60˚C to 250˚C) 0.032997125 W/(m.˚C)Water density at average Temperature of Drying Air and Wet Bulb T (100˚C to 240˚C) 893.4419355 kg/m3Coffee Liquid Mixture density for total Soluble Concentration from 5% to 60% 1222.171773 kg/m3Dynamic Viscosity of inlet Drying Air at Specified Temperature ( 60˚C to 250˚C ) 2.72042E-05 Pa.sAverage density of outlet gas of Drying Chamber 1.126980052 kg/m3Dynamic Viscosity of outlet Drying Air at Specified Temperature ( 60˚C to 250˚C ) 2.19052E-05 Pa.s

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CHEMICAL DESIGN OF SPRAY DRYING CHAMBER SPREADSHEET LAYOUT OF SPRAY DRYING CHAMBER FROM CHEMICAL DESIGN

DATA TO BE SET BY DESIGNER:

ATOMIZING DISK (CIRCULAR VANES) SPECIFICATION:

Atomizing Disk Rotational Speed 20000 rpm = 333.333333 rpsAtomizing Disk Diameter 0.2 m = 20 cm

COFFEE MIXTURE CHARACTERISTICS:

Droplet diameter Estimation at Critical moisture content 200 micron ( 0.0002 m)Proposed Design Data Tolerance (≥100%) 110 %

SUBSEQUENT DESIGN DATA GENERATION:

ATOMIZING DISK:

Peripheral Velocity 209.4395102 m/sMotor Power Rating (Shaft Driver ) 20.71827607 kW or 27.7624899 hpVane Height from Bottom of Conical Dist. 0.3 mNumber of Vanes (Circular) 20 VanesPeriphery opening Diameter 0.025 m = 2.5 cmConnecting pipe Diameter 0.066666667 m

COFFEE MIXTURE :

Initial Fraction of Water in Coffee Mixture Droplet 0.5 kg water /kg mixtureSauter Mean Diameter of Coffee Droplet 9.1248E-05 m or 91.248 micronMaximum Coffee Droplet Diameter 0.000273744 m or 273.744 micronTrajectory of Droplet from Disk Atomizer Periphery 3.080168065 m

CONSTANT DRYING RATE PERIOD OF COFFEE DROPLET DATA:

Fraction of Critical Moisture Content of Coffee droplet 0.2 kg water/kg Solid CHAMBER'S DIMENSION SPECIFICATION:Average moisture Vaporization (Constant rate) 3.83017E-09 kg/sInitial Droplet Volume 1.07407E-11 m3 at 50 % Moisture Level 1) Vertical Length of Particle accelerating zone (Conical) 7.1 mDroplet Volume at Critical Moisture Content 4.18879E-12 m3 at 20 % moisture Level 2) Vertical Distance of gas outlet pipe center from primary zone 3.55 mVolume difference at critical Moisture Content 6.5519E-12 m3 3) Drying Air Inlet Pipe Diameter 0.5005 mMoisture loss until critical moisture content 5.85375E-09 kg moisture loss 4) Air Distributor Diameter 3.5 mDroplet Initial mass 1.3127E-08 kg 5) Thickness of Air Distributor Wall Including Corrosion Allowance 0.005 mDensity of Coffee Droplet At Critical Moisture Content 1736.355217 kg/m3 6) Disk Atomizer's Vane height 0.3 m

Final moisture content in coffee Droplet 1.45465E-10 kg moisture at 2 % Moisture Level 7) Diameter of Atomizing disk 0.2 mAbsolute Weight of Coffee Solid (mass) 7.12776E-09 kg Coffee Solid 8) Thickness of Air Distributor Wall Including Corrosion Allowance 0.005 mInitial Moisture Content 7.12776E-09 kg Moisture 9) Outlet Gas (Air) Pipe Diameter 0.8001 mAmount of moisture remains at critical moisture content 1.45465E-09 kg moisture 10) Thickness of Cylindrical wall with corrosion allowance 0.01 mAmount of moisture removed at critical moisture content 5.67312E-09 kg moisture 11) Vertical Length of Air Distributor (cylindrical) 1.001 m

12) Vertical Length of Primary Drying Zone (Cylindrical) 2 mTime required for constant drying rate period ( until critical moisture content achieved) 1.481168 sec 13) Vertical Length of Chamber's Supporting Pillar 10 m

14) Thickness of conical Wall with Corrosion Allowance 0.01 m15) Angle of Conical Wall ( Particle Accelerating Zone ) 70˚ Degree

FALLING DRYING RATE PERIOD OF COFFEE DROPLET DATA: 16) Bottom Opening Diameter of Chamber (for Powder Collection) 1.75 m17) Diameter of Drying Chamber 7 m

Fraction of final moisture Content of Coffee droplet 0.02 kg water/kg Solid 18) Clearence From Floor 2 mAverage moisture vaporization (Falling Rate) 2.87951E-09 kg moisture/sAmount of Moisture Removed in Falling Rate Period 1.30918E-09 kg moisture lossTime Required to accomplish drying for Falling rate 0.4546544 sec

Total Drying Time of Coffee droplet until instant Coffee powder produced 1.935822 sec

DRYING CHAMBER DIMENSION SPECIFICATION:

PARTICULARS DESIGN VALUE PROPOSED VALUERadius of Drying Chamber 3.180168065 m 3.5 mDiameter of Drying Chamber 6.360336131 m 7 m Vertical Length of Primary Drying Zone (Cylindrical) 1.652037778 m 2 mVertical length of Particle accelerating zone (Conical) 6.616399192 m 7.1 m at cone angle θc + 70˚Air Distributor Diameter 3.180168065 m 3.5 mVertical Length of Air Distributor (cylindrical) 0.909528067 m 1.001 mDrying Air inlet Pipe Diameter 0.454764033 m 0.5005 mOutlet Gas (Air) Pipe Diameter 0.72698642 m 0.8001 mBottom Opening of Chamber (for Powder Collection) 1.590084033 m 1.75 mHeight of Outlet Gas Pipe centre From Chamber's bottom 3.308199596 m 3.55 mTotal Drying Chamber Height (without support pillar) 9.177965037 m 10.101 mTotal Drying Chamber Height (with support pillar) 11.17796504 m 12.101 mAir Distributor Volume without distributor cone 7.224472313 m3 9.630749 m3Drying Chamber Cylindrical Section Volume 52.48920457 m3 76.96902 m3Total Drying Chamber Volume (excluding Distributor) 163.5548459 m3 221.3308 m3Position of outlet gas pipe centre from primary zone 3.308199596 m 3.55 m

ORIGINAL SETTING OF SPRAY DRIER:

*MECHANICAL DESIGN OF SPRAY DRYING CHAMBER: BRIEF SPECIFICATION & OVERALL VIEW OF A SET OF SPRAY DRIER UNIT:

*All Mechanical Design Data follow to that of American Society of Mechanical Engineers (ASME) Standard1) Air Distributor Diameter 3.5 m

DATA TO BE SET BY DESIGNER: 2) Drying Air Inlet Pipe Diameter 0.5005 m3) Thickness of Air Distributor Wall Including Corrosion Allowance 5 mm

DRYING CHAMBER'S MATERIAL OF CONSTRUCTION: 4) Angle of Distributor Cone 45˚ Degree5) Connecting Pipe Shaft Diameter 66.66667 mm

Name the type of material used for piping and Chamber Commercial Carbon Steel 6) Air Distributor's Material of Construction Commercial Carbon SteelSet the Material Density 7854 kg/m3Set The Material Surface Roughness 0.0018 inch or 0.004572 mSet the Material Tensile Strength 360 N/mm2

Set the Material Design Stress at inlet T = 240 ˚C 97 N/mm2

Length of Inlet Pipe 5 mLength of outlet Pipe 10 mEfficiency of Compressor 80 %Coefficient of Chamber Safety Factor 2

INSULATION MATERIAL FOR DRYING CHAMBER:

Name the Selected Insulation material Mineral Wool Fiber Motor Power Rating 20.71828 kWSet the Insulation Density 32 kg/m3

DRYING CHAMBER'S SUPPORT: Chamber's Support name Bracket SupportType of support Double Gusset PlateCharacteristic Length 0.3 mPlate Thickness 0.15 m

SUBSEQUENT DATA GENERATION:Compressor Power 128.6028 kW

INLET PIPE: Efficiency 80 %

Velocity of Drying air at Proposed Design Value 34.45454 m/sReynolds Number of Inlet Drying Air 440447.3Surface Roughness to Pipe Diameter Ratio 0.009135 mFriction Factor of Pipe 0.009209Pressure Changes Inside the Inlet Pipe 151.7735 kPaPower Required for Air Compressor 128.6028 kW

OUTLET PIPE:

Velocity of Exhaust Air at Proposed Design Value 8.729842 m/sReynolds Number of Outlet Exhaust Air 359351 1) Connecting Pipe Diameter 0.066667 mSurface Roughness to Pipe Diameter Ratio 0.005714 m 2) Periphery Opening 0.025 mFriction Factor of Outlet Pipe 0.008101 3) Disk Diameter 0.2 mPressure Changes Inside the Outlet Pipe 17.39301 kPa Peripheral Velocity produced 209.4395 m/sPower Required for Outlet Air Compressor 9.542664 kW (Circular Vanes Atomizer)

Pressure Difference of inlet and outlet pipe (internal chamber pressure) 134.3805 kPaRecommended System Pressure with Safety Factor for Chamber Design 268.761 kPa

AIR DISTRIBUTOR:

Thickness or Air Distributor Wall 4.855508 mmThickness or Air Distributor Wall with Corrosion Allowance 5 mmCorrosion Allowance thickness for Air Distributor wall 0.144492 mm

DRYING CHAMBER'S WALL:Compressor Power 9.542664 kW

Thickness of Chamber Wall (Conical and Cylindrical) 9.711016 mm Efficiency 80 %Thickness or Chamber Wall with Corrosion Allowance 10 mmCorrosion Allowance thickness for Chamber wall 0.288984 mm

1) Chamber's Wall Thickness 10 mmDRYING CHAMBER'S SUPPORT : 2) Conical Wall Angle 70˚ Degree Bracket Support Double Gusset Plate

3) Material of Construction Commercial Carbon Steel 1) Plate Thickness 0.15 mDead Weight of Spray Drying Chamber 17080.23 kN Chamber's Volume 221.3308 m3 2) Characteristic Length 0.3 mDead Weight of Spray Drying Chamber with piping and Fitting Allowance 20000 kN System pressure (internal) 134.3805 kPa Maximum load per bracket 5400 kN

Chamber Safety Factor 2 Number of Brackets needed 4 BracketsMaximum Load Supportable by a Bracket 5400 kN Chamber's Dead Weight 20000 kN Pillar Height 10 mNumber of Bracket Support Required to Provide Support for Chamber 4 Brackets Total Supportable Load 21600 kNSupported load Provided by Specified Number of Brackets (up to) 21600 kNHeight of Pillar for Bracket Support 10 mClearence From Chamber's Powder Outlet to Floor (to collect product) 2 m

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