Effect of Liquid Media Height on the Pressure Drop during Production of Antibiotics in Bioreactor

 

S. Kumar¹*, A. Arora², H. Chandra³

¹Research Scholar, Department of Mechanical Engineering, Bhilai Institute of Technology,

Durg, Chhattisgarh, India

²Professor, Department of Mechanical Engineering, Bhilai Institute of Technology, Durg, Chhattisgarh, India

³Associate Professor, Department of Mechanical Engineering, Vishwavidyalaya Engineering College,

Sarguja University, Ambikapur, Chhattisgarh, India

 

ABSTRACT:

Three phase gas-liquid-solid systems are widely used by the pharmaceutical industries for the production of antibiotics such as patulin, penicillin, bacitracin etc. for which immobilized cell system or biofilms are used. During the process immobilized cells are fluidized in the liquid media using air. The present paper investigates regarding the dependency of the pressure drop on the height of liquid media present in the fluidizer.

 

 

 

INTRODUCTION:

Gas-liquid-solid fluidized systems are widely used in fermenters and bioreactors in which generally solid are immobilized cell particles and due to the presence of liquid and gas, a biochemical reaction takes place. The liquid phase is generally selected so as to increase the growth rate of cell. The gas phase selection is dependent on the selection of the process of fermentation in the bioreactor. That may be aerobic or anaerobic. For aerobic fermentation air can be used whereas for anaerobic process any of the inert gas can be used (Fan, 1989).

 

The immobilized cells are the formation of the solid growth having their cells are internally connected their entrapped structure. The growth of the cells which are connected to the other solids, are in a matrix form of multiple layer cells which is known as bio-film. In some special cases the immobilized cells are having the property to flocculate without the external carrier. These kind of immobilized cells are called as bio-flocculates (Fan, 1989).

 

 

 

For the industrial production of antibiotics such as patulin (Berk et al. 1984), penicillin (Nagamune et al. 1988), bacitracin (Morikawa et al. 1980) etc. the immobilized cell system can be used. In all these applications gas fluidizations of solids with liquid in batch and in non-continuous mode have been used. As on the basis of flowing and non-flowing state in three phase gas-liquid-solid fluidization process, Epstein (1981) suggested that three phase fluidized bed can be classified as concurrent fluidized bed, countercurrent fluidized and stationary liquid fluidized bed. In all the above mentioned applications of the fluidization such as fermentation or antibiotic production stationary mode of fluidization has been used where particles are supported by upward flow of gas in the presence of liquid.

 

The behavior of solids in the stationary mode is largely depends upon the flow rate of the gas. Kumar et al. (2018) investigated the regimes of the stationary liquid fluidization in gas-liquid-solid system. The present work has been undertaken for investigating the significance of the height of the liquid in the fluidizing column.

 

MATERIALS AND METHOD:

For investigating the effect of the height of the liquid in the fluidizing column on the pressure drop, experimentation has been performed on the fluidized bed test rig. The schematic diagram of the set-up has been given on the figure 1.

 

Table 1: Range of experimentation

Sr. No	Parameter	Range
1	Solid bed height, hs	25, 30 and 35cm
2	Stationary liquid height, h1	10 – 70 cm
3	Flow rate, q	0 – 101 pm
4	Average solid size, dp	0.002 m
5	Solid	Coal

 

The pressure drops during fluidization have been identified by conducting the experiments on air-water-peanut system. The experimental range has been presented in table 1. Experimentations have been conducted on the fluidization test rig by increasing the height of the water gradually. Peanuts have been used as solids for fluidizing. The pressure drop has been monitored precisely.

 

Figure 1: Experimental set-up

 

RESULTS AND DISCUSSIONS:

Presence of liquid phase in the gas-solid system significantly changes the fluidizing regime. As mentioned by Ruman et al. (2017), for achieving minimum fluidization in 5 cm fluidizing column of the air-coal system of 2 mm solid size and 10 cm bed height, requires air flow rate of 115 lpm. However, the presence of water of 10 cm height decreases the air flow rate significantly.

 

A graph (Figure 1.2) has been plotted for variation of pressure drop across column for different liquid pool heights for identifying the minimum air flow requirement to establish churn flow regime. From the analysis of Figure 1.3, it is clear that minimum air flow rate when stationary water height in the fluidizing column is 65 cm is 6.5 lpm. For other solid heights (25 cm, 30 cm and 35 cm), different stationary liquid heights have been taken in between 5 cm to 70 cm. For the different liquid heights, pressure drop has been measured.

 

Figure 2: Variation in pressure drop for increasing stationary liquid height

It is evident that the pressure drop curve has downward pattern upto a certain stationary liquid height ie. 35 cm. Subsequent increase in the stationary liquid height from 35 cm pressure drop again start rising gradually. It has also been observed that increasing trend very gradual and decreasing trend is very steep. The analysis results that the cohesive force between solid particles and liquid is predominant when small amount of liquid is present in the solid bed. Once the excessive liquid is present in the pool (as the liquid height is rising), it loosens the cohesion force which ultimately decreases the pressure drop as air can easily percolates the solid bed. Further, pressure drop also decreases as the volume of liquid increases because liquid exerts more buoyancy force on the solids. After 35 cm stationary liquid height the rising trend signifies that the total mass of solid and liquid present in the bed is too high to suspend the solids through bubbling which ultimately results the increase in the pressure drop. Similar trends have been observed for 30 cm and 25 cm static solid bed heights.

 

CONCLUSION:

For the production of antibiotics in the pharmaceutical industries, the immobilized cell growth systems are being used now days. For this purpose generally immobilized cells are fluidized by gas in the presence of liquid in the non-flowing state. It has been investigated that the presence of liquid state significantly reduces the requirement of air flow rate. Further, the height of the liquid has been optimized experimentally and found as 40 cm height for 30cm and 35 cm static solid bed height whereas for 35 cm is found for 25 cm solid bed height. The optimum minimum height of liquid leads to the saving of costly culture liquid media required for the biofilm cell growth.

 

REFERANCE:

1.       Morikawa, Y., Karube, I., and Suzuki, S. (1979). Penicillin G production by immobilized whole cells of Penicillium chrysogenum. Biotechnology and bioengineering, 21(2), 261-270.

2.       Epstein, N. (1981). Three-phase fluidization: Some knowledge gaps. The Canadian Journal of   Chemical Engineering, 59(6), 649-657. doi:10.1002/cjce.545059060.

3.       Berk, D., Behie, L. A., Jones, A., Lesser, B. H., and Maurice Gaucher, G. (1984). The production of the antibiotic patulin in a three phase fluidized bed reactor I. Effect of medium composition. The Canadian Journal of Chemical Engineering, 62(1), 112-119.

4.       Nagamune, T., Endo, I., Kato, N., Nishimura, M., and Kobayashi, T. (1988). The effect of cultivation conditions on the penicillin production using a urethane foam-supported Penicillium chrysogenum. Bioprocess Engineering, 3(4), 173-176.

5.       Fan, L. S. (1989). Gas-liquid-solid fluidization engineering. Butterworths Series In Chemical Engineering Series.7,16-20.

6.       Kumar, S., Arora, A., and Chandar, H. (2017). Effect of variation in solid bed height on the pressure distribution during gas fluidization of solids. BITCON March 17.Durg, C.G.: Research Journal of Engineering Sciences (Res. J. Engineering Sci.). (Vol. 6 (7), 7-13).

7.       Kumar, S., Arora, A., and Chandra, H. (2017). Effect of Variation in Solid Bed Height on Fluctuation Ratio during Gas Fluidization of Solids in Stationary Liquid. International Journal for Research in Applied Science and Engineering Technology (IJRASET), 5(12), 1642-1649.

8.       Ruman, S., Kumar, S., Kundu, A., Ahmed, S., (2017). Computational Fluid Dynamic Analysis of Gas Solid Fluidization. International Journal of Innovative Research in Science, Engineering and Technology, 6(10), 19890-19898.

9.         Kumar, S., Arora, A., and Chandar, H. (2018). Effect of variation in size of solids on the pressure distribution during gas fluidization of solids. BITCON February 18.Durg, C.G.: International Journal of Advanced in Management, Technology and Engineering Sciences, 8(2), 645-654.

10.     Kumar, S., Arora, A., and Chandra, H. (2018). Effect of Solid Bed Height on Pressure Drop in Stationary Liquid Fluidization. International Journal of Technology (IJT). 8(1), 11-15.

11.     Kumar, S., Arora, A., and Chandra, H. (2018). Flow Regimes in Stationary Liquid Fluidization. International Journal of Technology (IJT). 8(1), 6-10.

 

 

 

Received on 14.09.2018          Modified on 11.11.2018

Accepted on 21.12.2018        © RJPT All right reserved