The Influence of Rheological Properties on The Pump Power Requirement for Transfering Ketchup

This research aimed to analyze the influence of rheological properties of ketchup on the pump power, required during transporting process. This research was done through using a computer programme designed for calculating and analyzing the influence of rheological properties toward materials and equipments installed in the transport system. Those rheological properties derived from laboratory analysis and literature review include viscosity and density from any type of ketchup. Results analysed by a computer programming revealed that flow behaviour Index (n) and consistency coefficient (m) were the rheological properties interacting with each other since these parameters were the viscosity of ketchup that influences energy losses in the transport system. Once the total of energy losses was obtained from the system, the pump power required for transfering the product also can be known. Based on the simulation conducted by using rheological parameters of ketchup with consistency coefficient of 12.33 PaS n , and flow behaviour Index at 0.41 was obtained total energy losses at 202.26 J/kg with the pump power requirement at 0.22 kW. Once consistency coefficient was 18.7 PaS n , and flow behaviour Index was at around 0.4, the total of energy losses increased to 277.58 J/kg with pump power requirement at 0.28 kW.


I. INTRODUCTION
Rheology is known as the science of the deformation and flow of matter. It is also related to the study how materials respond to strain or stress (Steffe, 1996;Herth et al., 2000). Salas-Bringas et al. (2007) mentioned that food process rheology is often related to the behavior of liquid foodstuffs eventhough both solid and liquid materials can be considered as well. Monitoring viscosity online or inline during food processing has a number of difficulties because of the complex rheological property of typical fluid foods. For instance, foods may be multiphase, fibrous, elastic, shear thinning, particulate, and extremely viscous. Furthermore, several things that should be met in fluid food processing include high temperature and pressure demands specific design of equipment and sanitary requirements (Cullen et al., 2000;Ipsen, 2008). Measurements and rheological instruments are extremely important that should be available in the laboratory of food processing analysis in order to know material's properties, and the characteristics of final product (Herth et al., 2000).
Transport system of fluid food is very crucial to be done before packaging the end product. This operation is necessary to maintain products to be clean, and to generate product in a good quality. In food processing industry, fluid food is processed within several stages including heating, cooling, condensing, or other processes requiring pump (Heldman and Singh, 1980). Moreover, fluid foodprocessing systems should be designed in a manner that will ensure their cleanability. All equipments and materials utilized must meet sanitary standards (MQIP, 2009). Herth et al. (2000) mentioned that quality of fluid food product highly depends on its composition. Composition of fluid food product may be changed during transferring it from bioreactor to other containers. It occurs since materials and equipments used in the transport system are not clean enough, or free from all contaminants. Furthermore, during transferring fluid food, it is very crucial to monitor and maintain flow of the product in the tube in order to avoid agglomerate and foam of product that lead to damage the product. Thus, it is extremely important to know the pump power requirement to maintain the flow of fluid food product required in the transport system in order to generate and maintain quality of the product. Kusumah (1992) revealed that for food processing purpose, it is extremely important to select appropriate pipes and equipments utilized in the transport system in order to avoid any damages of fluid food products that are generated. When the fluid food flows within the tube, typically there is any challenging as well as friction that may lower its velocity. Friction that occurs during transferring the product may be influenced by several parameters including types of fluid and the material of pipes utilized. Furthermore, Heldman and Singh (1980) revealed that friction is the main factor that should be considered for applying rheological data to measure fluid flow in food processing. Friction force highly varies with different condition such as Reynold number and roughness surface. Friction may also influence flow of the product within many ways including flow within several layers, fluid flow on the tube surface and flow of the product through any changing in the fluid food transport system. Generally speaking, friction can be known as a force that flows with different direction to fluid flow that is observed (Heldman and Singh, 1993). Tipler (1991) mentioned that friction force is called as viscous force. Due to the friction force, fluid velocity is not constant through the tube. Furthermore, liquid viscosi-ty will increase when the temperature declines. Several factors that should be considered toward energy requirement for transferring liquid by using tubes include friction occurred through pipe, energy requirement for transferring liquid from one container to another container set up at higher place, energy required to maintain flow velocity expected, energy required to cope with different pressure between input and output from the pump. Moreover, friction may be generated from flow alteration, connecting pipes and friction generated from other equipments installed in the transfer system (Heldman and Singh, 1993).
To deal with issues appeared during transferring food fluid, it is necessary to assess the pump power requirement by considering its rheological parameters. This research aimed to study quantitative methods that can be utilized to reveal flow characteristics, and mathematic expression that can be used for determining energy losses as well as pump power required to transfer food fluids specifically ketchup in the transport system.

II. MATERIALS AND METHODS
Several equipments utilized in this research include power supply and drive, viscometer rheology international, digital balance and software of visual basic 6.0. Materials used in this research include ketchup with different density and viscosity. Several steps that should be considered and conducted include measurement of viscosity, energy losses, pump power requirement. Viscosity of ketchup obtained was considered as consistency coefficient, and flow behavior index. These parameters was utilized to determine flow types within transport system of ketchup designed. Furthermore, computer simulation was conducted to determine energy losses and pump power required to transfer ketchup derived from processing station without changing the system operated in food processing plants. Several data required to design the system include diameter of vessels and tubes, length of tubes, some equipments installed including valve, tee, heat exchanger, elbows, viscosity of ketchup including flow behavior index and coefficient consistency. Heldman and Singh (1980) revealed that transport system of food fluid highly depends on its rheological properties. This transport system is pretty different from the system used for water. For fluid food product, it is extremely important to avoid any damage such as foam generated during transferring process since it may lower product quality. To avoid any damage during the process, it is very crucial to know how much energy losses occurred in the system; thus, it may be used to know how much pump power requirement to be used in the transport system. Several parameters required to know how huch energy losses occurred in the system include flow rate of the product transferred, generalized reynold number, total head loss occurred through the tubes and other components such as tee, elbow, valve, heat exchanger, total of work within the system, and pump power requirement of the transport system.

III. RESULTS AND DISCUSSIONS
Analysis the influence of rheological properties of ketchup for designing its transport system is highly important since by understanding rheological properties of ketchup, energy losses occurred during the process can be determined; thus, pump power required for the transport system may be obtained. To avoid foam and agglomerate occurred during the transport process, it is necessary to know how much pump power required transferring food fluid product effectively. To analyze the influence of rheological properties of ketchup on the pump power requirement needs some rheological data from material used including viscosity, coefficient consistency and flow behavior index.
Simulation using computer program had some assumptions. First, length and diameter of tubes are the same size. The height from one vessel to the second vessel is constant. It is also assumed that there is no enlargement and suction within the tubes utilized in the transport system. This research was also aimed to investigate the influence of rheological properties of ketchup towards energy losses and pump power requirement.
Based on simulation results conducted by using computer program, it can be known that the higher coefficient consistency and flow behavior index, the more energy losses occurred in the transport system. This condition enables the pump power requirement to be higher. Results also revealed that type of flow occurred during transferring ketchup was laminar. This phenomenon showed that high value of coefficient consistency indicated that the viscosity of ketchup transferred was pretty high. It is known that ketchup, which has high viscosity tended to lower its flow velocity; thus, it may lead to generate a lot of energy losses. It may be derived from internal friction within the material, and friction derived from some equipments installed in the system. Heldman and Singh (1980) mentioned that to alter fluid flow velocity, the pump utilized has to enhance its kinetic energy from the fluid transferred. The influence of rheological properties of ketchup towards energy losses and pump power requirement can be seen on the relationship between coefficient consistency and energy losses occurred within the transport system, and the pump power required effectively for transferring the product.
Based on the Figure 1 and 2, it can be known that there is relationship between consistency coefficient and energy losses as well as pump power requirement. Generally, it can be seen that energy losses occurred in the transport system was influenced by consistency coefficient as well as flow behavior index, where energy losses increased when coefficient consistency of the fluid introduced was increased. It can be seen that when consistency coefficient of ketchup was 12.33 Pa.S n , energy losses occurred in the system was 202.26 J/kg, and the pump power requirement was 0.22 kW. Furthermore, when consistency coefficient of ketchup was increased at 18.7 Pa.S n , energy losses occurred in the system increased into 277.5 J/kg. This condition also enabled the pump power required to transfer ketchup also increased to 0.28 kW. However, Figure 1 and 2 also shows any discrepancy related to consistency coefficient and energy losses as well as pump power requirement where high consistency coefficient (13.4 and 19.05 Pa.S n , respectively) may not always increase energy losses (0.20 and 0.24 J/kg, respectively) in the system. This phenomenon occurred since flow behavior index also may influence energy losses as well as pump power requirement. When consistency coefficient of ketchup was 13.4 Pa.S n , its flow behavior index was slightly lower (0.36) compared with 12.33 Pa.S n of coefficient consistency that had higher flow behavior index at about 0.4. This condition also occurred when consistency coefficient of ketchup was 19.05 Pa.S n , flow behavior index was slightly lower (0.34) compared with 18.7 Pa.S n of consistency coefficient that had higher flow behavior index at about 0.4. Therefore, it is pretty clear that energy losses and pump power requirement were not only influenced by consistency coefficient, but they were also influenced by flow behavior index that is considered as rheological properties of ketchup. tency coefficient, but they were also influenced by flow behavior index that is considered as rheological properties of ketchup.
The influence of rheological properties of ketchup towards reynold number occurred in food fluid transport system may also describe deeper about energy losses and pump power requirement that were influenced by rheological properties. This can be seen on Figure 4. Based on Figure 4, it can be known that energy losses increased when reynold number was low. This condition occurred since when flow velocity of ketchup transferred was low, energy losses increased due to a lot of friction occurred through the tubes and other appliances installed including tees, valves, elbows and heat exchanger. Friction also occurred within the layers of ketchup as densed liquid where the more viscous of fluid transferred, the more friction occurred in the system that lead to enhance losses of energy within the transport system. In addition, Widiharsa (1997) mentioned that in order to maintain low friction in the transport system, it is better to utilize tube with bigger diameter and using elbows with longer radius.
Based on Figure 4, it also can be known that rheological properties of ketchup including consistency coefficient and flow behavior index may significantly influence type of flow occurred during transferring process. This phenomenon occurred since consistency coefficient and flow behavior index was derived from viscosity data of ketcup. Based on Figure 2 and 4, it is also can be known that when consistency coefficient value was 13.4 Pa.S n , reynold number occurred in the system was 18.62. However, when consistency coefficient of ketchup was 18.7 Pa.S n , reynold number declined significantly into 11.35. Therefore, it can be known that type of flow occurred in the system was laminar where Reynold number was lower than 2300. It also can be understood that the more viscous of the food fluid transferred, the slower the flow occurred within the system. It occurred since there was a lot of energy losses occurred in the system that lead to require higher power of the pump utilized to transfer ketchup from one vessel to another container.

IV. CONCLUSIONS
Based on the research conducted, it was known that rheological properties of ketchup including consistency coefficient and flow behavior index, highly influenced energy losses within the transport system since those parameters were considered as viscosity of ketchup. Therefore, the more energy losses occurred within the system, the higher pump power required.
Furhermore, it is recommended that to collect data and analyze other parameters such as elbow, tee, Heat Exchanger utilized in the transport system of ketchup. Thus, results derived from computer simulation would be better, and finally it may generate simulation software with high precision in terms of determining energy losses and pump power requirement.