REDESIGN AND IMPLEMENTATION OF CIRCULATING WATER PUMP AT PT. PJB UP PAITON

Transcription

1 REDESIGN AND IMPLEMENTATION OF CIRCULATING WATER PUMP AT PT. PJB UP PAITON Hendrik Setiawan*, I Komang Gede Suardika*, Tasha Oksaria*, Ahmad Susilawadi*, I Made Aksara*, Totok R. Biyanto** * PT. PJB UP PAITON, Paiton, Indonesia ** Engineering Physics Department, Institut Teknologi Sepuluh Nopember (ITS), Indonesia Abstract:- The abstract is to be in fully-justified italicized text as it is here, below the author information. Use the word Abstract as the title, in 14-point Times New Roman, boldface type, left aligned as shown, initially capitalized. The abstract is to be in 12-point, single-spaced type, and may be up to a 200 word length. Leave one blank line after the abstract, to be followed by the keywords, then begin the main text after leaving another blank line. All manuscripts must be in English. Keywords: We would like to encourage you to list 4 to 5 keywords in this section. I. Introduction PT. PJB UP Paiton is power plant unit that uses steam as the main propulsion or commonly referred to as Steam power plant (PLTU). The resulting steam is used to spin turbines located one shaft with rotor generator so that it can be produced electricity. After using to rotate the turbine, the steam is still storing the heat or energy, so that to raise the efficiency of power plant, the steam must be utilized in a system. But the steam can not get pumped back into the system directly so that should be condensed first on the condenser by releasing heat in the steam into condenser tubes containing cooling water that derived from sea water pumped by Circulating Water Pump (CWP) [1]. CWP is a centrifugal pump pumping sea water that comes from the inlet canal towards the condenser and then out through the outlet canal. In the condenser, sea water is pumped by the CWP flowing through the condenser tubes which has duty to condense steam coming out from the turbine. CWP is a very important component in the power plant system, so this tool should operate continuously when generating units in operation. When in operation, the motor bearing temperatures CWP will be high because the motor continues to spin, so the CWP motor bearings have to be cooled through the cooling system from its own. The initial design of the cooling system for motor bearing CWP is using sea water taken from the canal of Auxiliary Cooling Water (ACW) System. Then sea water flows towards the Bearing Injection Storage Tank so it will be pumped by the Bearing Injection Pump (BIP) to motor bearing and seal from CWP. When this system is applied, there are many obstacles i.e. often a broken BIP. This has resulted in decrease sea water that acts as a coolant motor bearing CWP. When there is no cooling water supply then CWP will trip. Therefore a system that uses sea water was replaced with a system that uses fresh water taken from Service Water tank. ISSN All Rights Reserved 2016 IJEETE Page 241

2 Service water that obtained from service water tank is drained towards the motor bearings and seal the CWP with the help of gravity. After using to seal and cool motor bearing CWP, water is directly dumped into the sea. Cooling water motor bearing that dumped into the sea will cause a financial loss and the environment. Therefore, by modifying the motor bearing cooling system that utilizes Closed Cooling Water (CCW) System, is expected to improve the operation of the system from the financial because of a reduction in the amount of water dumped from Service Water Tank into the ocean it can result in a reduction the payment of the levy on underground water, and from environment is because of the continuously used water that obtained from Service Water Tank. II. CWP Motor Bearing Cooling System J. Mitsui et al. studied about theoretical and experimental investigation on the cooling effect of supply oil in a circular bearing. Bearing frictional torque and temperature distribution in the bearing bush are focuses study [2]. CWP motor bearing cooling system is cooling system that utilizes water as the heat transfer medium. This water is piped into the House bearing containing lubricating oil through the pipeline circular immersed in lubricating oil. Due to the cooling water does not contact directly with the CWP motor bearing, then the quality of the cooling water from the CCW System will not decline. In addition, the minimum flow rate of cooling water that is allowed to cool the CWP motor bearing is 12.3 l/min, with the maximum water pressure is 5 bar, then the maximum limit water temperature is 40oC. Therefore, with more lowtemperature cooling water on the CCW System which is lower than the maximum limit of cooling water temperature motor bearing CWP i.e. 30oC- 33oC, it can be concluded that the cooling water that comes from the CCW System could be used to cool the CWP motor bearing well if it is reviewed based on the quality of the water or upon its cooling water temperature. CWP bearing cooling system motor is the water cooling system that does not circulate, so that the water that has been utilized to cool the CWP motor bearing and it is directly dumped into the sea. The flow rate of water that thrown away every day is 1.45 m3/h for 1 CWP. Because of the CWP has the capacity of 2 x 50%, so for every unit of the plant, the CWP that operates is 2 units, with 1 other CWP is in standby condition. Thus, the total number of operating on CWP UP Paiton Units 1 & 2 when both the plant operating is 4 units, so the amount of wasted water service is 4 x 1.45 m3/h or of 5.8 m3/h. III. Closed Cooling System (CCS) Closed Cooling Water (CCW) System is the water cooling system that uses to cool the equipment at the power plant unit. Lanchao Lin et al studied Heat transfer characteristics of spray cooling in a closed loop [3]. Thermal performance data for the multi-nozzle spray cooling in the confined and closed system are obtained at various operating temperatures, nozzle pressure drops and heat fluxes. Lanchao Lin et al also studied about critical heat flux of multi-nozzle spray cooling in a closed loop [4]. On other hand, closed cooling system can uses demine water / demineralized water as the heating transfer medium and it is pumped with Closed Cooling Water Pump (CCWP) with facilitated by Closed Cooling Water Tank Head to add pressure on the suction side of the CCWP. Because of the CCW System is a water cooling system that uses water demine, then the water cooling system is designed to become closed water cooling system and ISSN All Rights Reserved 2016 IJEETE Page 242

3 circulates constantly in order to maintain the utilizing demine water originated from the CCW quality of the demine water. In addition, the System. The water demine is taken from the line temperature of the cooling water from the CCW of the CCW System heading toward the Oil System is relatively low that is around 30 o C- 33 o C. By these parameters, the water cooling system can be utilized to replace CWP motor bearing cooling system that still uses the service water inefficiently (directly dumped into the sea). Service water UP Paiton comes from a water source (underground water) Klontong, so that UP Paiton must pay the retribution of underground water every month. Because it needs so many practices of water service as the needs for supporting the production process then the cost for the retribution of underground water will also get bigger. The Prices for the retribution of underground water is amount IDR 4380/m3. In the CWP motor bearing cooling system that now applied also uses the klontong and water pump and well water transfer pump. So in every day the retribution that must be paid and the cost of electricity to pump by UP Paiton is in the following : Table 1 Daily Cost Demand Demand Daily demand Cost (IDR) Total Cost (IDR) Water volume (m 3 ) Pump power (kwh) Water pump power (kwh) Service water cost IDR/day IV. Result and Discussion The main objective of the project assignment is the economization for using the service water by making the new line of the CWP motor bearing cooling system circulated continuously by Cooler from the Main Oil tanks (MOT). The pipeline is planned to begin from the inlet Oil Cooler MOT before Isolation Valve then heading to new pipeline branched off toward CWP A, B, and C for cooling the CWP motor bearing. From CWP A, B, and C, the demine water streamed back toward the outlet of the Oil Cooler MOT, exactly on the side after the Control Valve that operates to regulate oil temperature on MOT. From the oil cooler MOT to CWP is needed pipe along ± 154 m. With the details are the inlet pipe along ± 78 meters and outlet pie along ± 76 meters. So for the installation of the line from CWP motor bearing cooling system for units 1 and 2 are needed the pipe along ± 308 meters. For a unit, the new line is twenty-four elbows 90o and four T-junction for line inlet or outlet. For the design of piping layout is shown in the figure below: Figure 1 New Design of Piping Layout The line layout development is based on the real condition in the field. At the beginning of the line is in the area of oil cooler MOT, there have been several other piping lines such as piping water cooling condenser from CWP or ACWP and demine water from CCWP. So the planed line is also around another the pipeline in order that it would not interfere with the system or other equipment around the line. The planed pipeline in unit 1 or unit 2 adjusts with the availability of the room to the line where the planned line does not interfere with other systems. ISSN All Rights Reserved 2016 IJEETE Page 243

4 To replace the CWP motor bearing cooling Economic analysis is as an alternative to system that still uses the service water to be CWP consider in determining the feasibility planning motor bearing cooling system that uses cooling redesign cooling CWP motor bearing. To know water that comes from the CCW System, required the financial feasibility of the above study the a review of the operating parameters of the CWP required value of the investment required to motor bearing cooling system appropriating with apply those studies. The value of the its permit operation. The followings are the new investment can be seen in the table. The parameters of the CWP motor bearing cooling investment cost is the cost that is fixed for long system: periods of time. This fee covers the cost of purchasing the raw materials to be fitted for CWP motor bearing cooling system New Parameter of the CWP Motor Bearing Cooling System Temperature Pressure Flow Rate Water Parameter CCW System Operating Parameter Water Cooling CWP Figure 2 Parameter of the CWP Motor Bearing Cooling System Table 2 New Parameters of the CWP Motor Bearing Cooling System Water Parameter CCW System Operating Parameter Water Cooling CWP Temperature 30 o C 33 o C 40 o C (Max) Pressure kg/cm kg/cm 2 (Max) Flow Rate 1.5 m 3 /h m 3 /h From the above parameters in Figure 2 and Table 2, it can be considered that the cooling water that comes from the CCW System is used as cooler CWP motor bearing to replace the service water. V. Conclusion Water cooling parameters derived from Closed Cooling Water (CCW) System, are still in the operating limit of CWP motor bearing cooling water that are allowed (with temperature 30 o C 33 o C and pressure kg/cm2). From the financial studies, it can conclude that it requires the investment cost IDR 15,486, to realize the project assignment. From the Economic analysis is obtained the value of the Break Even Point (BEP) 0.6 years and the cost saving for expenditure that obtained is IDR 244,840, in every year. Acknowledgement The authors gratefully thank to PT. PJB UP Paiton Indonesia for providing the facilities in conducting this paper. REFERENCES [1] Nakato, Tatsuaki. Hydraulic-laboratory model studies of the circulating-water pumpintake structure, Florida Power Corporation, Crystal River Units 4 and 5. Iowa Institute of Hydraulic Research, the University of Iowa, [2] Mitsui, J., Y. Hori, and M. Tanaka. "Thermohydrodynamic analysis of cooling ISSN All Rights Reserved 2016 IJEETE Page 244

5 effect of supply oil in circular journal bearing." Journal of lubrication Technology (1983): [3] Lin, Lanchao, and Rengasamy Ponnappan. "Heat transfer characteristics of spray cooling in a closed loop." International Journal of Heat and Mass Transfer (2003): [4] J. Yang, L.C. Chow, M.R. Pais, Nucleate boiling heat transfer in spray cooling, J. Heat Transfer 118 (1996) [5] M.S. Sehmbey, M.R. Pais, L.C. Chow, Effect of surface material properties and surface characteristics inevaporative spray cooling, J. Thermophys. Heat Transfer 6 (3) (1992) [6] L. Lin, R. Ponnappan, Critical heat flux of multi-nozzle spray cooling in a closed loop, in: 37th Intersociety Energy Conversion Engineering Conference, Paper No , Washington, DC, [7] Dai, Cui, Fan-yu Kong, and Liang Dong. "Pressure fluctuation and its influencing factors in circulating water pump." Journal of Central South University 20 (2013): ISSN All Rights Reserved 2016 IJEETE Page 245