Advances in Natural and Applied Sciences

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1 Advances in Natural and Applied Sciences, 9(8) July 015, Pages: 6-4 AENSI Journals Advances in Natural and Applied Sciences ISSN: EISSN: Journal home page: Hazad And Operability Study and Analysis of Safety Integrity Level Case Study: Ammonia Refrigerant Compressor at Petrocemical Plant Ali Musyafa, Resti Nabila, Ronny D. Noriyati Department of Engineering Physics, Faculty of Industrial Technology, Sepuluh Nopember Institute Of Technology,Box. Surabaya, INDONESIA A R T I C L E I N F O Article history: Received 1 June 015 Accepted 8 June 015 Available online July 015 Keywords: Keyword 1 (Compressor); Keyword (Hazop); Keyword (SIS ); Keyword 4 (SIL ) ; Keyword 5 (PFD); A B S T R A C T Background: On the refrigeration system at the Petrocemical Plant there ammonia refrigerant compressor 105 J that operating to raise the vapor pressure of ammonia that comes from the refrigerant drum 10 CF flush and keep the pressure on the refrigerant flush drum 10 CF in order to maintain their liquid ammonia product temperature at - C. To avoid the risks that occur in ammonia refrigerant compressor 105 J we perform the identification of potential Hazard that can occur in the process in ammonia refrigerant compressor 105 J by using Hazard and Operability Analysis (HAZOP) and SIL analysis. In this study determined four nodes consisting of ammonia refrigerant compressor stage 1 to 105 J ammonia refrigerant compressor 105 J stage 4. Based on the identification of 0 instruments are installed on all four nodes, the valve components, namely the level of 104 which has a high risk based standards PT.Petrokimia Gresik. For Safety Integrity Level (SIL) value obtained from the calculation of Safety Instrumented System (SIS) in ammonia refrigerant compressor 105 J is NO SIL. With SIS Probability Failure Demand (PFD) worth 0. and RRF at :. The recommendations on the level of risk reduction valve 104 level by adding redundant generate failure rate is much lower at 4:45 x and PFD total of 1.8 x 10-4 worth SIS SIL. The recommendations of the panel in the form of local turnover based relay into Programable Logic Control (PLC) generates total PFD total =0.08 worth SIL AENSI Publisher All rights reserved. To Cite This Article: Ali Musyafa, Resti Nabila, Ronny D. Noriyati, Hazad And Operability Study and Analysis of Safety Integrity Level Case Study: Ammonia Refrigerant Compressor at Petrocemical Plant. Adv. in Nat. Appl. Sci., 9(8): 6-4, 015 INTRODUCTION The ammonia refrigeration system at ammonia plant uses refrigeration cycle system consisting of ammonia refrigerant flush drum, ammonia refrigerant compressor, condenser refrigerant and expansion valve. Ammonia refrigerant compressor consists of two cases, namely low pressure and high pressure. This compressor is driven by a turbine with a capacity of 5.65 KW, rotation of the turbine is controlled by a governor valve which includes steam which will drive the compressor at the same tubin. Aperture governor valve depends on the pressure that is on refrigerant drum flush stage 1 because the aim is to keep the pressure on the refrigerant flush drum. In addition it also has a compressor antisurge control which serves to protect the compressor from danger backflow due to the difference in pressure compressor suction and discharge. (Petrokimia Committee, M. T. 010). When there is damage to the compressor will pose a danger and a losses to the company because the ammonia production will be stopped. Therefore perform the identification of hazards that may occur in the process of ammonia refrigerant in the compressor in order to keep the process still takes place safely. Hazard identification method commonly used is the Hazard and Operability (HAZOP). With the HAZOP study method on a system that includes an evaluation and analysis of process deviations know who is known by the data process with several parameters such as flow, temperature and level. Evaluation studies conducted at four points using process data obtained during the first month (January 1, 015 until February 8, 015) with a time interval of hours, then plotted to determine the deviation that occurs by using Microsoft Excel. Then analysis the protection system of ammonia refrigerant compressor 105 J using Fault Tree Analysis (FTA) aimed at assessing the SIL level Corresponding Author: Ali Musyafa, Department of Engineering Physics, Faculty of Industrial Technology, Sepuluh Nopember Institute Of Technology, Kampus ITS Keputih, Sukolilo, Surabaya Indonesia, Tel: / musyafa@ep.its.ac.id

2 7 Ali Musyafa et al, 015 Advances in Natural and Applied Sciences, 9(8) July 015, Pages: 6-4 of the SIS that has been installed on the ammonia refrigerant compressor. (Petrokimia Committee, M. T. 010,)( Adiyagsa, H., & Musyafa, A. 01)). 1. Principle of Ammonia Refrigerant Compressor The early stages of the evaluation process is to learn the process and retrieval of data relating to the object of research, namely ammonia refrigerant compressor. Data needed as Piping and Instrument Diagrams (P&ID), Process Flow Diagram, Data Maintenance, and Process Data recorded by Distributed Control System (DCS). This study aims to determine the potential hazards and risks in ammonia refrigerant compressor unit with HAZOP method and determine the value of the Safety Integrity Level (SIL) of ammonia refrigerant compressor system. Ammonia refrigerant compressor to get input in the form of ammonia vapor that comes from the refrigerant flush drum. Compressor consists of four stages, namely the LP. Casing 1 st Stage, LP. Casing nd Stage, HP. 1 st Stage casing and HP. Casing nd Stage. (Petrokimia Committee, M. T.,010) Each stage serves to take the refrigerant vapor coming from the flush drum while keeping the pressure on the fourth stage flush refrigerant drum. Stage 1 is maintained the pressure about 0.05 kg / cm and temperature - C, stage kept the pressure around 1.8 kg / cm and temperature -1 C, stage kept the pressure around.4 kg / cm and temperature -1 C. Stage 4 kept the pressure around 7.9 kg / cm and temperature of 1 C which aims to keep the temperature remains cool liquid ammonia. 18 C 167-C TO 17 C HP. CASING nd STAGE HP. CASING LP. CASING nd STAGE LP. CASING TURBIN 105 JT 10 CF 4 TH STAGE 10 CF RD STAGE 10 CF ND STAGE 10 CF TK801 Fig. 1: Process of Ammonia Refrigerantm Compressor (Petrokimia Committee, M. T. 010,) Each stage in the ammonia refrigerant drums are flush antisurge control which serves to maintain the flow of input to the compressor suction still meet the minimum flow to prevent surges when flow towards the suction pressure becomes so low that low and high head while the pressure on the higher discharge causing backflow potentially damage the compressor. Control surge mounted on a stage 1 to stage 4 with a tag number and naming of this kind FIC 101/1011/1010/1009, FT 101/1011/1010/1009 and FV 101/1011/1010/1009. In addition there is also a surge control level control that keeps the drums flush level in order to avoid high-high level and low-low level because it will cause damage to the compressor. The process of system can be seen in Fig 1. (Ebeling, C. E. (1997).. Guide Word with Statistical Process Control: The next step is determining guide word from data process recording on DCS, the data is processed using a control chart Xbar-S chart using the equation: The X bar chart determined by equation: UCL = x + A s (1) CL = x () LCL = x - A s () where : x = The average value of subgroup s = The average of standard deviation of subgroup A = Constant based on the size of the subgroups

3 8 Ali Musyafa et al, 015 Advances in Natural and Applied Sciences, 9(5) July 015, Pages: The S -Chart determined by equation UCL = B 4 s (4) CL = s (5) LCL = B s (6) Where : B 4 and B are constants based on the subgroup size. From the data the process can be seen irregularities are legible and can be determined guide his word like No, of, of, as well as and. Then, based on data maintenance MTTF be obtained which is used to determined the likelihood. Likelihood can be searched by the equation: Τime intrererval- οf data aquisition Likelihood (7) ΜΤΤF Consequences is the impact of the incident. Criteria consequences and likelihood in this study using a standard PT. Petrokimia Gresik. Multiplication of likelihood and consequences generate risk matrix. (Adiyagsa, H., & Musyafa, A. 01), (Ebeling, C. E. (1997.). Table 1: Risk Matrix The classification level of risk at PT. Petro Kimia Gresik only are low risk, moderate risk and high risk. Based on the risk matrix that has been formed can be determined what instruments have the highest risk and then do an evaluation to reduce the risk of the instrument and determine actions. To analyze the safety instrumented system (SIS) in ammonia refrigerant compressor is used qualitative methods Fault Tree Analysis (FTA). FTA can identify the basic event so that events can be the cause of the initial event. Quantitative methods to calculate the Probability Failure on Demand (PFD). PFD system is determined based on the basic event that has been obtained from the analysis of the FTA. PFD system determines the SIL value system which can be seen in table. Table : PFD (Probability of Failure on Demand) of low demand operation and RRF for different SILs as defined in IEC EN SIL PFD RRF s/d s/d s/d s/d s/d s/d s/d d 10 SI 1005A SSHH 1005 PZ 1009 TO LP. CASING ND STAGE LP. CASING Turbin 105 JT TO SAHH 1005 FROM 105 J KICKBACK FV 1011 FY 101 PI 1646 PIC 1009 SI 1005B SSH 1005 TO SAH 1005 FIC 101 FT 101 PT 1009 FROM 10CF STAGE CF STAGE 1 LT 104 LIC 104 FY 10 LV 10 LAHH 117 COLD NH TO TK801 Fig. : Low Pressure Casing 1 st Stage of Turbine, UNEP, (January, )

4 9 Ali Musyafa et al, 015 Advances in Natural and Applied Sciences, 9(5) July 015, Pages: HAZOP Study: In this study the ammonia refrigerant compressor is divided into four nodes, namely, LP. Casing 1st Stage, LP. Casing nd Stage, HP. 1st Stage casing and HP. Casing nd Stage. This node determination based on the sequence masukknya ammonia vapor flow toward the compressor. At each node to be identified based on the data contained in the historical destruction of data maintenance for 10 years. Then the process of data taken with variable flow and level on each node. In the process of data collection have 9 transmitter readings are then processed by equation (1) to equation (6) using Microsoft excel. Here one Xbar Chart and S-Chart on node 1 is obtained by reading LT 104. Hyatt, N. (00), (ISA. 00) 4. Control Chart for Level Transminte 104: The deviation can be analyzed from the xbar chart, can be seen in Fig that there are points which are beyond the upper control limit (UCL) and there are points that are outside the lower control limit (UCL) so that deviations can be determined that is more level and less level. (Montgomery, D. C. 009). Fig. : Control Chart X bar 01LT104,Level Transmiter Fig. 4: Control Chart S - 01LT104,Level Transmiter As analyzed one by one by reading 9 transmitter located on the fourth node can be determined deviation and guide word shown in Table. Hyatt, N. (00), (ISA 00), (Musyafa, a., & Kristianingsih, l. 01). Table : Guide word and deviation node 1 Flow 01FV101 Flow Transmitter 01FT101 Flow 01LV104 Flow Flow 4 Level Transmitter 01LT104 Level Level 5 Pressure Transmitter 01PT1009 Pressure Pressure 6 Pressure Controller 01PIC1009 Pressure Pressure Table 4: Guide word and deviation node Flow 01FV1011 Level Transmitter 01LT10 Level Level 01LV10 Flow Flow 4 Intercooler 167 C High Misdirection High Temperature Misdirection Flow Table 5: Guide word and deviation node Flow 01FV1010 Flow Transmitter Flow 01FT LV10 Flow Flow 4 Level Transmitter 01LT10 Level Level 5 Intercooler 18 C High Misdirection High Temperature Misdirection Flow Table 6: Guide word and deviasation node 4 Flow 01FV1009 Flow Transmitter Flow Daily Daily

5 40 Ali Musyafa et al, 015 Advances in Natural and Applied Sciences, 9(5) July 015, Pages: FT LV101 4 Level Transmitter 01LT101 Table 6: Risk Matrix Ammonia Refrigerant Compressor Flow Flow Level Level Based on the risk analysis has been done, by multiplying the likelihood and consequences of the following are the results of the existing risk matrix at node 1 to node 4. (ISA. 00 Results of risk matrix of four nodes of ammonia refrigerant compressor 105 J, the risk of having a low percentage of 1.6 %. Moderate risk has the highest percentage amount by 7.97% and high risk with the least amount of percentage is 5:40%. Shown in Risk Matrix Annex-1. Alarm Overspeed 105 JT (B) SSHH 1005 (P) Alarm High High Level 10 CF (A) SIS Ammonia Refrigerant Compressor 105 J Failure (T) Local Panel Alarm High High Failure Vibrasi (C) (A) Relay ZSHH Failure 6510 (Q) (O) XV 6501 (V) ESDV (D) XV 650 (X) RESULTS AND DISCUSSION 117 (K) 116 (L) 115 (M) 114 (N) SIL Analysis, Safety instrumented system (SIS) in ammonia refrigerant compressor serves as a protection to the security system in the process of ammonia refrigerant compressor when BPCS have been unable to cope with danger. SIL calculation analysis on SIS in ammonia refrigerant compressor is done by using logic Fault Tree Analysis (FTA) to see the basic event of the cause of its failure occurred in the SIS in ammonia refrigerant compressor, and then calculate PFD based on logic are obtained. FTA which has a top event SIS failure as fig. 5, (Hyatt, N. 00), (ISA. 00). Fig. 5: FTA for SIS compressor (Musyafa, A. et al. 01). Based on fault tree in fig 5 can be determined with an equation Boolean logic in the following: T = A B C D = (K L M N ) O P Q (R S) = (K L M N ) O P Q ((V) (X)) = K + L + M + N + O + P + Q + ( (V) * (X)) So that PDF-SIS calculation based on basic even that is acquired is: Table 7: Calculation of PFD_SIS. Instrument Failure Rate PFD PFD SIS RRF 1.74x SSHH 0.48x ZSHH 0.57x Relay 0.66x XV 6501.x XV x The value of pfd sis obtained from the calculation of the existing sis is 0., based on table and the value of pfd 0. not included in the level of the SIL 1-4, so worth NO SIL. (SINTEF. 009), Recommendation: Based on the evaluation hazop that has been done there are two deviation with the risk of high that was found at the nodes 1.The high risk to exist at the level of valve instrument 104. To reduce the risk of failure caused by instrument of 104 then give the recommendations to add redundant on instrument high risk:

6 41 Ali Musyafa et al, 015 Advances in Natural and Applied Sciences, 9(5) July 015, Pages: Existing LV 104: Instrument MTTF C L RR 01LV x 10-5 PFD LV10 T x i (5.4x10 ) x 0., No _ SIL Then added level valve as a redundant valve so that the vote turned into 1oo, with the result that, LV 104 λ = 4.45 x 10^-10 PFD xti 6 (8.5x10 ) x(6760 ) redundant = 1.74 x 10 - PFD xti 5 (5.4x10 ) x(9760 ) LV104 = = PFD total = (1.74 x 10 - ) x = 1.8 x 10-4 (SIL ) λ LV 104 λ LV 104 With the result that change into : Instrument MTTF C L RR λ 01LV x Based on the analysis to the existing SIS SIL in ammonia refrigerant compressor 105 J produces NO SIL value. The largest component PFD value derived from the local panel 105 J, as based on the failure of local panel causes the most of his trip compressor. PLC to be recommended is TUV certified Honeywell PLC for SIL with a failure rate of 7.4 x So if the local panel is replaced with a failure rate then the calculation becomes: PFD PLC = T x i (7.4x10 ) x PFD SIS = PFD + PFD ZSHH + PFD SSHH + PFD LocalPanel + PFD ESDV =[ ] [( ) x (0.8)] = = 0.08 = (SIL 1, IEC EN standard ). The results of the replacement of local panel can increase the value of the SIL.The existing SIL worth no SIL and the recommendation is worth the SIL 1. Conclusion: Based on the risk matrix of four nodes of ammonia refrigerant compressor 105 J, the risk of having a low percentage of 1.6%. Moderate risk have the highest percentage amount by 7.97% and high risk with the least amount of percentage is 5:40%. Based on the HAZOP evaluation has been done, a component with a high risk of a fourth node in Ammonia Refrigerant Compressor 105 J is the level of 104 by criteria likelihood valve 4 and consequences appreciating 4. The value of SIL in ammonia refrigerant compressor 105 J is NO SIL, with PFD system 0. and RRF :. This is because the failure rate of a local panel of 105 J is high at 6:55 x 10-5 so that pfd value of its local panel. The recommendations on the level of risk reduction valve 104 level by adding redundant produce a failure rate that is much lower at 4:45 x and PFD total worth of 1.8 x 10-4 SIL. The results of the SIS recommendations in the form of replacement of relay-based local panel into the PLC generates total PFD 008 is worth SIL1. REFERENCES Adiyagsa, H., A. Musyafa, 01. Hazard and Operability study in Boiler System of The Steam Power Plant. IEESE International Journal of Science and Technology (IJSTE), 1(). Ebeling, C.E., An Introduction to Reliability andmaintainability Engineering. Singapore: The McGraw HillCompanies. Hyatt, N., 00. Guidelines for Process Hazard Analysis, Hazards Identification & Risk Ananlysis. London, New York, Washington D.C: CRC Press. ISA, 00. Safety Instrumented Functions (SIF) - Safety Integrity Level (SIL) Evaluation Techniques Part 1: Introduction. ISA The Instrumentation,Systems, and Automation Society. ISA, 00. Safety Instrumented Functions (SIF) - Safety Integrity Level (SIL) Evaluation Techniques Part : Determining the SIL of a SIF via Simplified Equations. ISA The Instrumentation, Systems, and Automation Society. Montgomery, D.C., 009. Introduction to Statistical Quality Control (Vol. Six Edition). John Wiley & Sons, Inc. Musyafa, A., 01. Risk Management Using HAZOP Study Method Base Fault Tree Analysis on Emergency Shutdown System-Vacuum Distillation Unit, PT.PQR, Dumai, Indonesia, Asian Transactions on Engineering (ATE ISSN: 1-467) Volume 0 Issue 05.

7 4 Ali Musyafa et al, 015 Advances in Natural and Applied Sciences, 9(5) July 015, Pages: Musyafa, A., 014. Reliability and Maintainability Assessment of the Steam Turbine Instrumentation System for optimization Operational Availability System at Fertilizer Plant Australian journal of Basic and Applied Science (AJBAS), ISSN: Published August & Journal home page: Musyafa,, A., l. Kristianingsih, 01. Risk Management and Safety System Assessment from Power Plant Steam Boiler in Power Systems Unit 5, Paiton-Indonesia. Australian Journal of Basic and Applied Sciences, pp: Petrokimia Committee, M.T., 010. Risk Management Training Guides. Manufacturing Technology Committee Risk Management Working Group. plc, M.I., 00. An introduction to Functional Safety and IEC SINTEF. 009., Industrial Management. Offshore Reliability Data Handbook 4 th Edition. OREDA Participants,000 UNEP, (January, ), COMPRESSORS AND COMPRESSED AIR SYSTEM, Energy Efficiency Guide for Industry in Asia Unido, 014. Compressor Air System, Unido Patner and prosperity Annex-1: Risk Matrix Annex -1: Risk Matrix of ammonia refrigerant compressor 105 J Guide word Deviation Cause Consequences Safeguard Risk Score C L RR Flow FV 101 failed to close when the minimum input flow on the suction LP.casing 1st stage has been reached Control surge malfunction due to damage to the FT 101 (upper) Occurs higher pressure and high temperature in the LP. 1st stage suction casing but no mechanical failure FV valve 101 opening is not in accordance with requirements PAH 1009 RV 1018 PAH-1009 RV Flow LV 104 fails to close or does not match the required percentage Level An interruption in the flow output 10-CF1 to storage tanks because of an error reading by LT 101 Flow LV 104 failed to open or did not fit the required percentage Level Input ammonia liquid derived from 10 CF too low The loss of liquid level at 10 CF1 which can lead to comp.105 J surges and damaged High level at 10 CF1 allows entrainment of liquid ammonia into the comp. 105 J can make the broken blade and shutdown comp. 105 J Level high at 10 CF1 allows entrainment of liquid ammonia into the comp. 105 J can make a blade is damaged and shut down comp. 105 J The loss of liquid level at 10 CF1 which can lead to comp.105 J surges and damaged LAL LAH-104 LAHH-117 leads to 105-J trip LAH-104 LAHH-117 leads to 105-J trip LAL