Operating Manual
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OPERATING MANNUAL FOR SPARGER DESIGN SOFTWARES
INSTITUTE OF CHEMICAL TECHNOLOGY MATUNGA, MUMBAI 400 019 INDIA
Correspondence : [email protected] Tel : +91 22 24145616; Fax : +91 22 24145614
Operating Manual
INTRODUCTION The sparger design software is based on the research work published in following two articles. The following two articles discuss the detail design procedure for all types of sparger for bubble column reactor and hence the design procedure is not discussed here.
1) Kulkarni, A. V., Roy S. S., Joshi, J. B. (2007), Pressure and flow distribution in pipe and ring spargers : Experimental measurements and CFD simulations, Chem. Engg. J., 133, 173-186. 2) Kulkarni, A. V., (2009), Design of Pipe/Ring Type of Sparger for Bubble Column Reactor, Chem. Engg. Technol., accepted for publication. 3) Kulkarni, A. V., Badgadi, S.V., Joshi, J. B., (2009) Design of Ring and Spider type of Spargers for Bubble Column Reactor : Experimental Measurements and CFD simulation of flow pattern and weeping, Chem. Engg. Res. Des., Forwarded for publication.
OBJECTIVE :
The Sparger design software is intended to enable to take decision over all the parameters involved in sparger design for bubble column reactor. Further an attempt is made while preparing the software that the practicing engineer can dispatch the design for fabrication at the end.
SOFTWARES :
This manual describes the operating procedure and the meaning of various terms used for following type of spargers :
SPARGER TYPE
PATH OF EXECUTABLE FILE
Radial Sparger (Figure 1)
software\radial\distrib\radial.exe
Conventional spider sparger (Figure 2)
software\spider1\distrib\sparger1.exe
Conventional spider sparger with pitch software\spider2\distrib\sparger2.exe changes on each arm (Kulkarni et al. (2009)),
Operating Manual Figure 2 Spider sparger with feed from center and software\spider3\distrib\sparger3.exe pitch changes on each arm (Kulkarni et al. (2009)), Figure 3 Multiple ring sparger with single entry and software\modring\distrib\modring.exe pitch changes on each arm (Kulkarni et al. 2009), Figure 4 Wheel type of sparger Figure 5
NOTE :
software\wheel\distrib\wheel.exe
All softwares were developed in MATLAB™ and executable files were generated by using MATLAB™. All executables would run only in Windows environment. In order to use any of these software the practicing engineer SHOULD
INSTALL
“MATLAB
(MCRInstallation)” on their computer.
Component
Runtime
7.5
setup
Operating Manual
Arms
Column
Header Ring
Computational domain under consideration Gas inlet
Figure 1 Radial Sparger
Operating Manual
Computational domain under consideration
Gas inlet
Arms
Header
Column
Figure 2. Conventional Spider sparger
Operating Manual
Figure 3A
Computational domain under consideration
Arms
Header
Gas inlet Column
Figure 3C
Figure 3B C D
A
B E
Figure 3.Spider with entry from center and pitch changes on each arm
Operating Manual
Gas inlet
Arms Header
Column
Figure 4. Multiple ring sparger with single entry
Operating Manual
Bubble column
Various layers of arms
Chamber Gas
Gas
Figure 5 Wheel sparger
Operating Manual
Graph 1 : Selection of header and pipe diameter 0.2 dH 0.15m; dH 0.15m; dH 0.15m; dH 0.25m; dH 0.25m; dH 0.25m; dH 0.35m; dH 0.35m; dH 0.35m;
15000 10000
dH 0.15m; dH 0.15m; dH 0.15m; dH 0.25m; dH 0.25m; dH 0.25m; dH 0.35m; dH 0.35m; dH 0.35m;
dp 0.0254m dp 0.038m dp 0.051m dp 0.0254m dp 0.038m dp 0.051m dp 0.0254m dp 0.038m dp 0.051m
Pressure drop (Pa)
5000
dp 0.0254m dp 0.038m dp 0.051m dp 0.0254m dp 0.038m dp 0.051m dp 0.0254m dp 0.038m dp 0.051m
0.15
0.1
0.05
0
5
10
15
20
25 number of pipes (-)
30
35
Figure 6 Graph 1 for selection of header diameter and pipe diameter
40
45
0 50
Pressure drop ratio (-)
20000
Operating Manual
Graph 2 : Selection of design parameters 100 pitch/do 2 pitch/do 3 pitch/do 4 pitch/do 5 pitch/do 6 pitch/do 8 pitch/do 10 pitch/do 12 pitch/do 15
Total pressure drop (Pa)
10000
pitch/do 2 pitch/do 3 pitch/do 4 pitch/do 5 pitch/do 6 pitch/do 8 pitch/do 10 pitch/do 12 pitch/do 15
80
60
5000
40
20
1
1.5
2
2.5
3
3.5 Hole diameter (mm)
4
4.5
Figure 7 Graph 2 selections of design parameters for sparger
5
5.5
0 6
Number of pipes (-)
15000
Operating Manual THE STRUCTURE OF SOFTWARE This section provides the general structure of all softwares. However the additional input/output parameters may require/given as output for individual sparger design software. These additional parameters have been described at the end for individual sparger design software. At this stage it would be appropriate to give outline of sparger design though the detail procedure can be referred in the above mentioned references.
Outline of sparger design (Kulkarni (2009)) 1) Estimate the gas hold up. 2) Estimate critical weep point velocity. 3) Estimate number of holes. 4) Estimate total length required. 5) Estimate the number of pipes (arms) so that total length required is satisfied. 6) Estimate the pressure drop across the header and arm and pressure drop ratio for various number of pipes (arms). 7) Select the appropriate header and pipe (arm) diameter. 8) Estimate the total pressure drop and number of pipes (arms). 9) Select the design parameters. 10) Estimate the hole velocity profiles and check the extent of non-uniformity, average hole velocity, and deviation from critical weep velocity.
General outline of sparger design software 1) Give all inputs in panel 1 and Press “Start” Button 2) Select header diameter and pipe (arm) diameter from Graph1
Operating Manual 3) Give selected header diameter and pipe (arm) diameter as input in panel 2 4) Message box will appear mentioning to press “Verify” button. 5) Press “Verify” button 6) Message box will appear mentioning to press “Proceed” button 7) Select design parameters as hole diameter and pitch (∆x/do) from Graph 2 8) Give selected hole diameter and pitch (∆x/do) as input in panel 3 9) Message box will appear mentioning to press “Check” button. 10) Press “Check” button 11) Message box will appear mentioning to press “Profiles” button 12) Press “Profiles” button to see the hole velocity profile and other results. 13) Press “Reset” button. It will reset all input, intermediate input and output parameter to zero. Now the software is ready for any new case. NOTE : Since for ring type of sparger, correlation for momentum recovery factor is not available, profiles will not be generated. In case of wheel type of sparger, the non-uniformity in gas distribution from chamber to arm cannot be estimated since such relations are not available in literature. Assumption : For any sparger design software it is assumed that maximum 100 pipes (arms) could be accommodated in a given column. The counting of number of pipes (arms) is straight forward except for radial and spider type of sparger. In case of radial sparger, the computational domain is half circle as shown by a dotted rectangle in Figure 1. This is based on experimental observation that radial spargers provide symmetric flow distribution with respect to entrance (Kulkarni et al. 2007). In case of spider type of sparger with feed entering from either end, the computational domain is half circle as shown by a dotted rectangle in Figure 2. This is specifically because the flow distribution in other half is symmetric
Operating Manual (Kulkarni (2009)). In this case, the total number of pipes (arms) is twice than that in a single half circle. In case of spider sparger with feed from center, the computational domain is a quadrant as shown by a dotted rectangle in Figure 3. This is because the flow distribution would be symmetric in other quadrants. In this case the total number of pipes (arms) is four times of that in a single quadrant. In any case the total number of pipes provided by software is based on the above mentioned counting method. Instructions to operate and use the softwares 1) Give all input parameters and press ‘Start’ button. Description of all input parameters is given in Table 1. Table 1 provides the common input parameters and any additional input parameter required is given in the section of specific sparger design. 2) Select header diameter and pipe diameter from Graph 1 Guidelines to read Graph 1 : Graph1 is the operating map for selection of set of header diameter (dH) and pipe diameter (dp) and NOT for selection of number of pipes (arms). Graph1 is the combination of two graphs 1) pressure drop versus number of pipes (arms) for various set of dH and dp and 2) pressure drop ratio versus number of pipes (arms) for various set of dH and dp. The ordinate for all lines (and symbols therein) in red color is on RHS and that in black color is on LHS. Since this graph combines two graphs with a common parameter, set of dH and dp, the symbol remains the same for a specific number of pipes (arms). This means assume some value of number of pipes (arms) and read any specific symbol, associated to a set; in black color then ordinate on LHS would give the pressure drop value. Refer the same symbol for the same number of pipes (arms) however in red color then ordinate on RHS gives the pressure drop ratio. However it is recommended to start from some value of pressure drop ratio (ordinate on RHS), since pressure drop ratio gives degree of non-uniformity in header, which is
Operating Manual expected to be minimum. Starting with some value of pressure drop ratio (usually not greater than 0.25) and read the symbol in red color for any corresponding set of dH and dp, read corresponding number of pipes (arms). Read the same symbol in black color for same number of pipes (arms). It is certain that more than one set of dH and dp would satisfy these conditions, under these circumstances, the set which gives minimum pressure drop for maximum number of pipes (arms) is to be selected. For example assume Figure 6 is a typical case under consideration. Then start with pressure drop ratio of 0.1. For this case, three sets of dH and dp covers the entire range of number of pipes (arms) (dH 0.35m, dp 0.0254m, dH 0.35m dp 0.038m and dH 0.25m dp 0.0254). The other sets however cover respective limited number of pipes (arms). Now for these three sets corresponding value of pressure drop can be read from ordinate on LHS by referring the same symbol in black color. It can be seen that the set of dH 0.35m, dp 0.0254m gives maximum pressure drop and other two sets gives nearly similar pressure drop value for any value of number of pipes (arms). Hence if selection is to be made within these three sets, then set of dH 0.25m dp 0.0254 is logically optimum since it gives less pressure drop in comparison to other sets as well as fixed cost for this set would be minimum as compared to other two case. Referring back to the pressure drop ratio the selected set gives higher value of pressure drop ratio as compared to set dH 0.35m dp 0.0254m. Hence it is obvious that non-uniformity would be higher. Such comparison can be done with all other sets as well. 3) Give input of selected header diameter and pipe diameter (Note : Graph 1 provides the pressure drop and pressure drop ratio for various sets of header diameter and pipe diameter, specifically header diameter ranges 0.15m, 0.25m, 0.35m and pipe diameter ranges from 0.0254m, 0.038m, 0.051m, which forms nine sets. However, while
Operating Manual selecting header diameter and pipe diameter it is NOT necessary to give values from above mentioned sets. One can give any input as header diameter, such as 0.45m or 0.3m etc which is not considered in the set. Same is applicable for pipe diameter.) 4) Press Verify button. Since user can give any value of header and pipe diameter which are not considered in the assumed set the software recalculates the pressure drop and pressure drop ratio for various number of pipes (arms). The software simply checks whether ratio of pipe diameter to header diameter is higher that 0.33. If it is there are maximum chances that few arm would run dry, i.e. non-uniformity is too high. Hence under these circumstances software would recommend to select lower value of pipe diameter or user can increase the header diameter. 5) Press Proceed button. At this stage software computes the operating map for design parameters and will be represented by Graph 2. 6) Select the design parameters as hole diameter, pitch, number of pipes (arms) and total pressure drop within the sparger, from Graph 2. Guidelines to read Graph 2. Graph 2 is the operating map for selection of design parameters. This is also the combination of two graphs : 1) Total pressure drop versus hole diameter with pitch as a parameter represented by black line and associated symbols and 2) Number of pipes (arms) versus hole diameter with pitch as a parameter represented by red lines and associated symbols. This graph is also to be read in a similar way as Graph 1. The user can start from any point like hole diameter, or total pressure drop or number of pipes (arms). This graph is operating map specifically because the selection of either hole diameter or total pressure drop or number of pipes (arms) solely depends upon the specific process under consideration. Selecting a specific hole diameter and a specific total pressure drop automatically sets the pitch and the number of pipes
Operating Manual (arms). Otherwise selecting either a specific hole diameter and a specific number of pipes (arms) automatically sets the pitch and total pressure drop. For example assume Figure 7 is a typical case under consideration. It is already mentioned that ordinate for all red line and symbol is on RHS and all black line and symbol is associated on LHS. If the symbol is same regardless which color it is the pitch is same. If a process demands hole diameter not to exceed than 3mm, then assume hole diameter as 3mm. Also assume pitch as 3. Read the total pressure drop given by black line which is nearly 13000 Pa. Use the same symbol however on red line and same hole diameter of 3mm, the number of pipes (arms) can be obtained from the ordinate on RHS as nearly 5. If the pressure drop appears too high then increase pitch, as 4. For this case total pressure drop can be obtained as 6500 Pa and again the number of pipes (arms) can be found to be 7. If total pressure is to be reduced further then increase pitch, as 8. The total pressure drop would now be 1300 Pa and corresponding number of pipes (arms) would be 38. Similar comparison can be made with any specific hole diameter. For the above mentioned case it is the designer’s choice to select specific parameter. In case of radial spargers the structural limitations always put the upper limit for number of pipes (arms) however this is not the case for spider or multiple ring or wheel type of sparger. 7) To see the pressure profiles within sparger, select the design parameters from Graph 2. However it is NOT mandatory that one should choose the design parameter specifically the pitch from the values given in Graph 2. It means designer can give value of pitch as 9 or 11 or 13 or 30 etc. For bubble column reactor it would be unusual to choose hole diameter higher than 6mm however it’s the designer choice. 8) Press Check button. Since designer is free to choose any value of hole diameter and pitch this step simply checks whether number of pipes (arms) obtained for specific
Operating Manual values are not too high. It means the spacing between two pipes (arms) is not less than the pipe diameter itself. 9) Press Profiles buttons. With this the software will give all results in concern with the design parameters and will provide the hole velocity profiles for the computational domain under consideration along with the output variables mentioned in Table 2. The hole velocity profiles are normalized with respect to the hole velocity in the first hole of first arm. 10) Press Reset button. This will reset all input, intermediate input and output parameters to zero and software is ready for any other case. Note : All input data SHOULD BE given in SI units and all output data is provided in SI units. TABLE 1. INPUT PARAMETERS PARAMETER
DESCRIPTION
Superficial gas velocity (m/s)
Superficial gas velocity in ‘m/s’ is to be given
Column diameter (m)
Column diameter is to be given in ‘meters’.
Minimum pipe diameter (m)
The software computes the pressure drop
Minimum header diameter (m) +
across the header and pipe (arm) and pressure drop ratio for various sets of header diameter and pipe (arm) diameter. Hence Minimum pipe (arm) diameter as well as header diameter (m) is required. Both values are required to be given in ‘meters’. It is recommended to start with the pipe (arm) diameter as 0.0254 m and header diameter as
Operating Manual 0.15 m. Operating Pressure (Pa)
Operating pressure of the column in Pascal.
Liquid density (kg/m3)
Density of the liquid under consideration in (kg/m3).
Liquid viscosity (Pa.S)
Viscosity of liquid under consideration in Pa.S
Gas viscosity (Pa.S)
Viscosity of gas phase under consideration in (Pa.S)
Liquid surface tension (N/m)
Surface tension of liquid phase under consideration is to be given in N/m
Gas density (kg/m3)
Density of gas phase under consideration is to be given in kg/m3
Safety Margin (-)
This is the safety margin for critical weep velocity. If safety margin is 20 % then it should be given as 1.20 and NOT 20 or 0.2.
+ This input argument is not available for Wheel type of sparger
TABLE 2. OUTPUT PARAMETERS OUTPUT PARAMETER
DESCRIPTION
Number of pipes (arms) (-)
Number of pipes (arms) required for the selected design parameters.
Total number of holes (-)
Total number of holes required for selected design parameters.
Total Pressure drop (Pa)
Total pressure drop required for the selected
Operating Manual design parameters in Pascal. Non-uniformity (-)**
This the is non-uniformity in hole velocity over the entire sparger. The non-uniformity is estimated in fraction NOT in per cent.
Average hole velocity (m/s)**
Mean hole velocity for the entire sparger in m/s.
Critical weep velocity (m/s)**
Critical weep velocity for the selected design parameters. This value excludes the safety margin.
Pitch on header (m) +
This is the distance between two adjacent arms on the header in ‘meters’
Percent of minimum hole velocity with This is the deviation in minimum hole respect to critical weep velocity.** +
velocity with respect to critical weep velocity in per cent.
Arm number of minimum hole velocity
This the arm number where minimum hole
(-)** +
velocity lies.
** These output arguments are not available for multiple ring sparger. + These output arguments are not available for Wheel type of sparger.
SPECIFIC INPUT/OUTPUT ARGUMENTS FOR INDIVIDUAL SOFTWARE 1) Radial sparger (Figure 1) : In case of radial sparger there is no additional input data required. However there are two additional out puts are given 1) Length of single arm : The length of single arm is estimated as 80 % of column radius. 2) Ring diameter : Ring diameter is taken as 1.3 times the column diameter.
Operating Manual 2) Spider sparger with feed from center and pitch changes on each arm (Figure 3) : There are two additional input parameters for this type of sparger 1) Margin for arms from center. This is the distance between the first arm (starting from center) and the central inlet as shown in Figure 3B. Since header diameter is unknown at this stage, 0.15m has already been deducted, i.e. component “B” as shown in Figure 3B. The software requires the component “A” as shown in Figure 3B. If header diameter is selected less than 0.3m then additional margin need to be added similarly if header diameter is higher than 0.3m then some margin is to be deducted. This value can be taken in between 0.15m to 0.2m. 2) Margin for arms. Various margins required for any arm are shown in Figure 3C. As mentioned earlier the 0.15m has already been deducted in the software, i.e. the component C shown in Figure 3C. In addition to these component D and component E need to be considered. Hence Software demands the total contribution of component D and component E as shown Figure 3C. This value can be taken in between 0.15m to 0.2m. In addition to these input parameters the software provides the details of each arm, in an output text file, named “spidres1.txt”. The first column in this text file is the arm number (starting from center), then length of each arm, pitch (∆x/do ratio) on each arm, number of holes on each arm, critical weep velocity on each arm, and minimum hole velocity on each arm in the subsequent columns respectively. Note : These results are generated for the single quadrant under consideration, i.e. the computational domain as shown in Figure 3A and would be symmetric in rest other quadrants. 3) Spider sparger with feed from either end and pitch changes on each arm (Figure 2) :
Operating Manual This sparger design software requires only one additional input, i.e. margin for pipe length. This is the same margin as described in Figure 3C. This software also provides the details for each arm in an output text file named “spidmodres1.txt”. The first column in this text file is the arm number (starting from either extreme), followed by length of each arm, pitch (∆x/do ratio) on each arm, number of holes on each arm, critical weep velocity for each arm and minimum hole velocity on each arm in the subsequent columns respectively. Note : These results are generated for the half circle as shown by a dotted rectangle in Figure 2. This is the computational domain under consideration. The other half has symmetric flow distribution (Kulkarni (2009)) hence arm details are also symmetric. 4) Conventional spider with feed from either end (Figure 2) : This sparger design software requires only one additional input, i.e. margin for pipe length. This is the same margin as described in Figure 3C. As in case of other spider types this software the details for each arm are given in a text file “spidconvres.txt”. The first column in this file gives the arm number starting from either extreme, followed by length of each arm, number of holes on each arm, critical weep velocity for each arm and minimum hole velocity on each arm in the subsequent columns respectively. Note : These results are generated for the half circle as shown by a dotted rectangle in Figure 2. This is the computational domain under consideration. The other half has symmetric flow distribution (Kulkarni (2009)) hence arm details are also symmetric. Further the pitch is not changing on each arm hence pitch is same as selected parameter for all arms. 5) Multiple ring sparger with pitch changes on each ring (arm) (Figure 4) :
Operating Manual In case of multiple ring, margin on ring is to be given as additional input parameter. This is specifically the distance between first hole and header. As in previous cases 0.15m has been deducted from the software as radius of header. Hence if selected header diameter is larger than 0.3m, this margin would reduce to some extent and if it is less than then additional length may be added to the margin. The design details for each ring are given in a text file “mringres.txt”. The first column is the ring number, followed by pitch (∆x/do ratio) on each arm, ring diameter of each ring and number of holes on each ring is given in subsequent columns respectively. 6) Wheel type of sparger (Figure 5) : In case of Wheel type of sparger there is no header. Hence input as well as output parameters associated with header are not required. In Wheel type of sparger there is a central chamber hence length (height) of chamber and diameter of chamber is required input parameters. The diameter of chamber is to be chosen based on column diameter. However one can start with 0.5m or 0.6m as chamber diameter. The length (Height) of chamber depends on the dispersed height. However the chamber length (height) could be any where between 0.5m to 1m would be appropriate. The total number of pipes (arms) is to be placed in various layers, hence the distance between two adjacent pipes (arms) and distance between two adjacent layers both can be chosen arbitrarily. However it is recommended that distance between two adjacent pipes (arms) should not be less than 0.1m and distance between two adjacent layers should not be less than 0.05m. Since both these estimations are straight forward these are not included in the software. The length of a single pipe (arm) is taken as R-Rc0.15, where R is the column radius, Rc is the radius of chamber and 0.15m is the margin.
INSTITUTE OF CHEMICAL TECHNOLOGY MATUNGA, MUMBAI 400 019 INDIA
Correspondence : [email protected] Tel : +91 22 24145616; Fax : +91 22 24145614
Operating Manual
INTRODUCTION The sparger design software is based on the research work published in following two articles. The following two articles discuss the detail design procedure for all types of sparger for bubble column reactor and hence the design procedure is not discussed here.
1) Kulkarni, A. V., Roy S. S., Joshi, J. B. (2007), Pressure and flow distribution in pipe and ring spargers : Experimental measurements and CFD simulations, Chem. Engg. J., 133, 173-186. 2) Kulkarni, A. V., (2009), Design of Pipe/Ring Type of Sparger for Bubble Column Reactor, Chem. Engg. Technol., accepted for publication. 3) Kulkarni, A. V., Badgadi, S.V., Joshi, J. B., (2009) Design of Ring and Spider type of Spargers for Bubble Column Reactor : Experimental Measurements and CFD simulation of flow pattern and weeping, Chem. Engg. Res. Des., Forwarded for publication.
OBJECTIVE :
The Sparger design software is intended to enable to take decision over all the parameters involved in sparger design for bubble column reactor. Further an attempt is made while preparing the software that the practicing engineer can dispatch the design for fabrication at the end.
SOFTWARES :
This manual describes the operating procedure and the meaning of various terms used for following type of spargers :
SPARGER TYPE
PATH OF EXECUTABLE FILE
Radial Sparger (Figure 1)
software\radial\distrib\radial.exe
Conventional spider sparger (Figure 2)
software\spider1\distrib\sparger1.exe
Conventional spider sparger with pitch software\spider2\distrib\sparger2.exe changes on each arm (Kulkarni et al. (2009)),
Operating Manual Figure 2 Spider sparger with feed from center and software\spider3\distrib\sparger3.exe pitch changes on each arm (Kulkarni et al. (2009)), Figure 3 Multiple ring sparger with single entry and software\modring\distrib\modring.exe pitch changes on each arm (Kulkarni et al. 2009), Figure 4 Wheel type of sparger Figure 5
NOTE :
software\wheel\distrib\wheel.exe
All softwares were developed in MATLAB™ and executable files were generated by using MATLAB™. All executables would run only in Windows environment. In order to use any of these software the practicing engineer SHOULD
INSTALL
“MATLAB
(MCRInstallation)” on their computer.
Component
Runtime
7.5
setup
Operating Manual
Arms
Column
Header Ring
Computational domain under consideration Gas inlet
Figure 1 Radial Sparger
Operating Manual
Computational domain under consideration
Gas inlet
Arms
Header
Column
Figure 2. Conventional Spider sparger
Operating Manual
Figure 3A
Computational domain under consideration
Arms
Header
Gas inlet Column
Figure 3C
Figure 3B C D
A
B E
Figure 3.Spider with entry from center and pitch changes on each arm
Operating Manual
Gas inlet
Arms Header
Column
Figure 4. Multiple ring sparger with single entry
Operating Manual
Bubble column
Various layers of arms
Chamber Gas
Gas
Figure 5 Wheel sparger
Operating Manual
Graph 1 : Selection of header and pipe diameter 0.2 dH 0.15m; dH 0.15m; dH 0.15m; dH 0.25m; dH 0.25m; dH 0.25m; dH 0.35m; dH 0.35m; dH 0.35m;
15000 10000
dH 0.15m; dH 0.15m; dH 0.15m; dH 0.25m; dH 0.25m; dH 0.25m; dH 0.35m; dH 0.35m; dH 0.35m;
dp 0.0254m dp 0.038m dp 0.051m dp 0.0254m dp 0.038m dp 0.051m dp 0.0254m dp 0.038m dp 0.051m
Pressure drop (Pa)
5000
dp 0.0254m dp 0.038m dp 0.051m dp 0.0254m dp 0.038m dp 0.051m dp 0.0254m dp 0.038m dp 0.051m
0.15
0.1
0.05
0
5
10
15
20
25 number of pipes (-)
30
35
Figure 6 Graph 1 for selection of header diameter and pipe diameter
40
45
0 50
Pressure drop ratio (-)
20000
Operating Manual
Graph 2 : Selection of design parameters 100 pitch/do 2 pitch/do 3 pitch/do 4 pitch/do 5 pitch/do 6 pitch/do 8 pitch/do 10 pitch/do 12 pitch/do 15
Total pressure drop (Pa)
10000
pitch/do 2 pitch/do 3 pitch/do 4 pitch/do 5 pitch/do 6 pitch/do 8 pitch/do 10 pitch/do 12 pitch/do 15
80
60
5000
40
20
1
1.5
2
2.5
3
3.5 Hole diameter (mm)
4
4.5
Figure 7 Graph 2 selections of design parameters for sparger
5
5.5
0 6
Number of pipes (-)
15000
Operating Manual THE STRUCTURE OF SOFTWARE This section provides the general structure of all softwares. However the additional input/output parameters may require/given as output for individual sparger design software. These additional parameters have been described at the end for individual sparger design software. At this stage it would be appropriate to give outline of sparger design though the detail procedure can be referred in the above mentioned references.
Outline of sparger design (Kulkarni (2009)) 1) Estimate the gas hold up. 2) Estimate critical weep point velocity. 3) Estimate number of holes. 4) Estimate total length required. 5) Estimate the number of pipes (arms) so that total length required is satisfied. 6) Estimate the pressure drop across the header and arm and pressure drop ratio for various number of pipes (arms). 7) Select the appropriate header and pipe (arm) diameter. 8) Estimate the total pressure drop and number of pipes (arms). 9) Select the design parameters. 10) Estimate the hole velocity profiles and check the extent of non-uniformity, average hole velocity, and deviation from critical weep velocity.
General outline of sparger design software 1) Give all inputs in panel 1 and Press “Start” Button 2) Select header diameter and pipe (arm) diameter from Graph1
Operating Manual 3) Give selected header diameter and pipe (arm) diameter as input in panel 2 4) Message box will appear mentioning to press “Verify” button. 5) Press “Verify” button 6) Message box will appear mentioning to press “Proceed” button 7) Select design parameters as hole diameter and pitch (∆x/do) from Graph 2 8) Give selected hole diameter and pitch (∆x/do) as input in panel 3 9) Message box will appear mentioning to press “Check” button. 10) Press “Check” button 11) Message box will appear mentioning to press “Profiles” button 12) Press “Profiles” button to see the hole velocity profile and other results. 13) Press “Reset” button. It will reset all input, intermediate input and output parameter to zero. Now the software is ready for any new case. NOTE : Since for ring type of sparger, correlation for momentum recovery factor is not available, profiles will not be generated. In case of wheel type of sparger, the non-uniformity in gas distribution from chamber to arm cannot be estimated since such relations are not available in literature. Assumption : For any sparger design software it is assumed that maximum 100 pipes (arms) could be accommodated in a given column. The counting of number of pipes (arms) is straight forward except for radial and spider type of sparger. In case of radial sparger, the computational domain is half circle as shown by a dotted rectangle in Figure 1. This is based on experimental observation that radial spargers provide symmetric flow distribution with respect to entrance (Kulkarni et al. 2007). In case of spider type of sparger with feed entering from either end, the computational domain is half circle as shown by a dotted rectangle in Figure 2. This is specifically because the flow distribution in other half is symmetric
Operating Manual (Kulkarni (2009)). In this case, the total number of pipes (arms) is twice than that in a single half circle. In case of spider sparger with feed from center, the computational domain is a quadrant as shown by a dotted rectangle in Figure 3. This is because the flow distribution would be symmetric in other quadrants. In this case the total number of pipes (arms) is four times of that in a single quadrant. In any case the total number of pipes provided by software is based on the above mentioned counting method. Instructions to operate and use the softwares 1) Give all input parameters and press ‘Start’ button. Description of all input parameters is given in Table 1. Table 1 provides the common input parameters and any additional input parameter required is given in the section of specific sparger design. 2) Select header diameter and pipe diameter from Graph 1 Guidelines to read Graph 1 : Graph1 is the operating map for selection of set of header diameter (dH) and pipe diameter (dp) and NOT for selection of number of pipes (arms). Graph1 is the combination of two graphs 1) pressure drop versus number of pipes (arms) for various set of dH and dp and 2) pressure drop ratio versus number of pipes (arms) for various set of dH and dp. The ordinate for all lines (and symbols therein) in red color is on RHS and that in black color is on LHS. Since this graph combines two graphs with a common parameter, set of dH and dp, the symbol remains the same for a specific number of pipes (arms). This means assume some value of number of pipes (arms) and read any specific symbol, associated to a set; in black color then ordinate on LHS would give the pressure drop value. Refer the same symbol for the same number of pipes (arms) however in red color then ordinate on RHS gives the pressure drop ratio. However it is recommended to start from some value of pressure drop ratio (ordinate on RHS), since pressure drop ratio gives degree of non-uniformity in header, which is
Operating Manual expected to be minimum. Starting with some value of pressure drop ratio (usually not greater than 0.25) and read the symbol in red color for any corresponding set of dH and dp, read corresponding number of pipes (arms). Read the same symbol in black color for same number of pipes (arms). It is certain that more than one set of dH and dp would satisfy these conditions, under these circumstances, the set which gives minimum pressure drop for maximum number of pipes (arms) is to be selected. For example assume Figure 6 is a typical case under consideration. Then start with pressure drop ratio of 0.1. For this case, three sets of dH and dp covers the entire range of number of pipes (arms) (dH 0.35m, dp 0.0254m, dH 0.35m dp 0.038m and dH 0.25m dp 0.0254). The other sets however cover respective limited number of pipes (arms). Now for these three sets corresponding value of pressure drop can be read from ordinate on LHS by referring the same symbol in black color. It can be seen that the set of dH 0.35m, dp 0.0254m gives maximum pressure drop and other two sets gives nearly similar pressure drop value for any value of number of pipes (arms). Hence if selection is to be made within these three sets, then set of dH 0.25m dp 0.0254 is logically optimum since it gives less pressure drop in comparison to other sets as well as fixed cost for this set would be minimum as compared to other two case. Referring back to the pressure drop ratio the selected set gives higher value of pressure drop ratio as compared to set dH 0.35m dp 0.0254m. Hence it is obvious that non-uniformity would be higher. Such comparison can be done with all other sets as well. 3) Give input of selected header diameter and pipe diameter (Note : Graph 1 provides the pressure drop and pressure drop ratio for various sets of header diameter and pipe diameter, specifically header diameter ranges 0.15m, 0.25m, 0.35m and pipe diameter ranges from 0.0254m, 0.038m, 0.051m, which forms nine sets. However, while
Operating Manual selecting header diameter and pipe diameter it is NOT necessary to give values from above mentioned sets. One can give any input as header diameter, such as 0.45m or 0.3m etc which is not considered in the set. Same is applicable for pipe diameter.) 4) Press Verify button. Since user can give any value of header and pipe diameter which are not considered in the assumed set the software recalculates the pressure drop and pressure drop ratio for various number of pipes (arms). The software simply checks whether ratio of pipe diameter to header diameter is higher that 0.33. If it is there are maximum chances that few arm would run dry, i.e. non-uniformity is too high. Hence under these circumstances software would recommend to select lower value of pipe diameter or user can increase the header diameter. 5) Press Proceed button. At this stage software computes the operating map for design parameters and will be represented by Graph 2. 6) Select the design parameters as hole diameter, pitch, number of pipes (arms) and total pressure drop within the sparger, from Graph 2. Guidelines to read Graph 2. Graph 2 is the operating map for selection of design parameters. This is also the combination of two graphs : 1) Total pressure drop versus hole diameter with pitch as a parameter represented by black line and associated symbols and 2) Number of pipes (arms) versus hole diameter with pitch as a parameter represented by red lines and associated symbols. This graph is also to be read in a similar way as Graph 1. The user can start from any point like hole diameter, or total pressure drop or number of pipes (arms). This graph is operating map specifically because the selection of either hole diameter or total pressure drop or number of pipes (arms) solely depends upon the specific process under consideration. Selecting a specific hole diameter and a specific total pressure drop automatically sets the pitch and the number of pipes
Operating Manual (arms). Otherwise selecting either a specific hole diameter and a specific number of pipes (arms) automatically sets the pitch and total pressure drop. For example assume Figure 7 is a typical case under consideration. It is already mentioned that ordinate for all red line and symbol is on RHS and all black line and symbol is associated on LHS. If the symbol is same regardless which color it is the pitch is same. If a process demands hole diameter not to exceed than 3mm, then assume hole diameter as 3mm. Also assume pitch as 3. Read the total pressure drop given by black line which is nearly 13000 Pa. Use the same symbol however on red line and same hole diameter of 3mm, the number of pipes (arms) can be obtained from the ordinate on RHS as nearly 5. If the pressure drop appears too high then increase pitch, as 4. For this case total pressure drop can be obtained as 6500 Pa and again the number of pipes (arms) can be found to be 7. If total pressure is to be reduced further then increase pitch, as 8. The total pressure drop would now be 1300 Pa and corresponding number of pipes (arms) would be 38. Similar comparison can be made with any specific hole diameter. For the above mentioned case it is the designer’s choice to select specific parameter. In case of radial spargers the structural limitations always put the upper limit for number of pipes (arms) however this is not the case for spider or multiple ring or wheel type of sparger. 7) To see the pressure profiles within sparger, select the design parameters from Graph 2. However it is NOT mandatory that one should choose the design parameter specifically the pitch from the values given in Graph 2. It means designer can give value of pitch as 9 or 11 or 13 or 30 etc. For bubble column reactor it would be unusual to choose hole diameter higher than 6mm however it’s the designer choice. 8) Press Check button. Since designer is free to choose any value of hole diameter and pitch this step simply checks whether number of pipes (arms) obtained for specific
Operating Manual values are not too high. It means the spacing between two pipes (arms) is not less than the pipe diameter itself. 9) Press Profiles buttons. With this the software will give all results in concern with the design parameters and will provide the hole velocity profiles for the computational domain under consideration along with the output variables mentioned in Table 2. The hole velocity profiles are normalized with respect to the hole velocity in the first hole of first arm. 10) Press Reset button. This will reset all input, intermediate input and output parameters to zero and software is ready for any other case. Note : All input data SHOULD BE given in SI units and all output data is provided in SI units. TABLE 1. INPUT PARAMETERS PARAMETER
DESCRIPTION
Superficial gas velocity (m/s)
Superficial gas velocity in ‘m/s’ is to be given
Column diameter (m)
Column diameter is to be given in ‘meters’.
Minimum pipe diameter (m)
The software computes the pressure drop
Minimum header diameter (m) +
across the header and pipe (arm) and pressure drop ratio for various sets of header diameter and pipe (arm) diameter. Hence Minimum pipe (arm) diameter as well as header diameter (m) is required. Both values are required to be given in ‘meters’. It is recommended to start with the pipe (arm) diameter as 0.0254 m and header diameter as
Operating Manual 0.15 m. Operating Pressure (Pa)
Operating pressure of the column in Pascal.
Liquid density (kg/m3)
Density of the liquid under consideration in (kg/m3).
Liquid viscosity (Pa.S)
Viscosity of liquid under consideration in Pa.S
Gas viscosity (Pa.S)
Viscosity of gas phase under consideration in (Pa.S)
Liquid surface tension (N/m)
Surface tension of liquid phase under consideration is to be given in N/m
Gas density (kg/m3)
Density of gas phase under consideration is to be given in kg/m3
Safety Margin (-)
This is the safety margin for critical weep velocity. If safety margin is 20 % then it should be given as 1.20 and NOT 20 or 0.2.
+ This input argument is not available for Wheel type of sparger
TABLE 2. OUTPUT PARAMETERS OUTPUT PARAMETER
DESCRIPTION
Number of pipes (arms) (-)
Number of pipes (arms) required for the selected design parameters.
Total number of holes (-)
Total number of holes required for selected design parameters.
Total Pressure drop (Pa)
Total pressure drop required for the selected
Operating Manual design parameters in Pascal. Non-uniformity (-)**
This the is non-uniformity in hole velocity over the entire sparger. The non-uniformity is estimated in fraction NOT in per cent.
Average hole velocity (m/s)**
Mean hole velocity for the entire sparger in m/s.
Critical weep velocity (m/s)**
Critical weep velocity for the selected design parameters. This value excludes the safety margin.
Pitch on header (m) +
This is the distance between two adjacent arms on the header in ‘meters’
Percent of minimum hole velocity with This is the deviation in minimum hole respect to critical weep velocity.** +
velocity with respect to critical weep velocity in per cent.
Arm number of minimum hole velocity
This the arm number where minimum hole
(-)** +
velocity lies.
** These output arguments are not available for multiple ring sparger. + These output arguments are not available for Wheel type of sparger.
SPECIFIC INPUT/OUTPUT ARGUMENTS FOR INDIVIDUAL SOFTWARE 1) Radial sparger (Figure 1) : In case of radial sparger there is no additional input data required. However there are two additional out puts are given 1) Length of single arm : The length of single arm is estimated as 80 % of column radius. 2) Ring diameter : Ring diameter is taken as 1.3 times the column diameter.
Operating Manual 2) Spider sparger with feed from center and pitch changes on each arm (Figure 3) : There are two additional input parameters for this type of sparger 1) Margin for arms from center. This is the distance between the first arm (starting from center) and the central inlet as shown in Figure 3B. Since header diameter is unknown at this stage, 0.15m has already been deducted, i.e. component “B” as shown in Figure 3B. The software requires the component “A” as shown in Figure 3B. If header diameter is selected less than 0.3m then additional margin need to be added similarly if header diameter is higher than 0.3m then some margin is to be deducted. This value can be taken in between 0.15m to 0.2m. 2) Margin for arms. Various margins required for any arm are shown in Figure 3C. As mentioned earlier the 0.15m has already been deducted in the software, i.e. the component C shown in Figure 3C. In addition to these component D and component E need to be considered. Hence Software demands the total contribution of component D and component E as shown Figure 3C. This value can be taken in between 0.15m to 0.2m. In addition to these input parameters the software provides the details of each arm, in an output text file, named “spidres1.txt”. The first column in this text file is the arm number (starting from center), then length of each arm, pitch (∆x/do ratio) on each arm, number of holes on each arm, critical weep velocity on each arm, and minimum hole velocity on each arm in the subsequent columns respectively. Note : These results are generated for the single quadrant under consideration, i.e. the computational domain as shown in Figure 3A and would be symmetric in rest other quadrants. 3) Spider sparger with feed from either end and pitch changes on each arm (Figure 2) :
Operating Manual This sparger design software requires only one additional input, i.e. margin for pipe length. This is the same margin as described in Figure 3C. This software also provides the details for each arm in an output text file named “spidmodres1.txt”. The first column in this text file is the arm number (starting from either extreme), followed by length of each arm, pitch (∆x/do ratio) on each arm, number of holes on each arm, critical weep velocity for each arm and minimum hole velocity on each arm in the subsequent columns respectively. Note : These results are generated for the half circle as shown by a dotted rectangle in Figure 2. This is the computational domain under consideration. The other half has symmetric flow distribution (Kulkarni (2009)) hence arm details are also symmetric. 4) Conventional spider with feed from either end (Figure 2) : This sparger design software requires only one additional input, i.e. margin for pipe length. This is the same margin as described in Figure 3C. As in case of other spider types this software the details for each arm are given in a text file “spidconvres.txt”. The first column in this file gives the arm number starting from either extreme, followed by length of each arm, number of holes on each arm, critical weep velocity for each arm and minimum hole velocity on each arm in the subsequent columns respectively. Note : These results are generated for the half circle as shown by a dotted rectangle in Figure 2. This is the computational domain under consideration. The other half has symmetric flow distribution (Kulkarni (2009)) hence arm details are also symmetric. Further the pitch is not changing on each arm hence pitch is same as selected parameter for all arms. 5) Multiple ring sparger with pitch changes on each ring (arm) (Figure 4) :
Operating Manual In case of multiple ring, margin on ring is to be given as additional input parameter. This is specifically the distance between first hole and header. As in previous cases 0.15m has been deducted from the software as radius of header. Hence if selected header diameter is larger than 0.3m, this margin would reduce to some extent and if it is less than then additional length may be added to the margin. The design details for each ring are given in a text file “mringres.txt”. The first column is the ring number, followed by pitch (∆x/do ratio) on each arm, ring diameter of each ring and number of holes on each ring is given in subsequent columns respectively. 6) Wheel type of sparger (Figure 5) : In case of Wheel type of sparger there is no header. Hence input as well as output parameters associated with header are not required. In Wheel type of sparger there is a central chamber hence length (height) of chamber and diameter of chamber is required input parameters. The diameter of chamber is to be chosen based on column diameter. However one can start with 0.5m or 0.6m as chamber diameter. The length (Height) of chamber depends on the dispersed height. However the chamber length (height) could be any where between 0.5m to 1m would be appropriate. The total number of pipes (arms) is to be placed in various layers, hence the distance between two adjacent pipes (arms) and distance between two adjacent layers both can be chosen arbitrarily. However it is recommended that distance between two adjacent pipes (arms) should not be less than 0.1m and distance between two adjacent layers should not be less than 0.05m. Since both these estimations are straight forward these are not included in the software. The length of a single pipe (arm) is taken as R-Rc0.15, where R is the column radius, Rc is the radius of chamber and 0.15m is the margin.
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