The Feed Line of a Propane-Butane Separation Column System - Coursework Example

Piping system Customer Inserts His/Her Name Customer Inserts Grade Course Customer Inserts Tutor’s Name 06, 05, 2014 A. List 5 possible system hazards and carry out a hazard analysis based on a checklist. Table 3: system hazard Asset Risk exposure Evacuation Property damage Tank leaks 3 4 1 Over pressure 3 2 2 Faulty valve 4 2 Overheating 3 1 Blast 4 4 4 Likelihood table Likelihood 1 Low Not expected to occur 2 Medium Possible 3 High It will occur 4 Very Must occur The reason why this ranking system was used is that this is the standard practice for checklist and besides this classification indicates the level of occurrence B. Explain how the HAZOP technique can be used for the identification of causal events and hazards, and as an example, provide a fragment of the HAZOP table for the system described above. (Include about 4 items). (Only for the flow parameter). HAZOP stand for Hazard and Operability Study which is a detailed and structured technique for analyzing deviations from design in chemical process systems like the Butane-propane piping system. It detects procedural errors, failures, and other events. In the case at hand, the following is the HAZOP table Process- variable No Low high Part of also Other than reverse Flow No flow Low flow High flow one component Im purities Wrong pipe Reverse flow Level nothing Yes Yes Low interface High interface - - pressure use atmosphere Low High - - - vacuum temperature freezing Yes Yes - - - Auto re frigeration Use the FMECA approach to identify system hazards and produce a fragment of the FMECA table of the system described above (include about 5 items). FMECA is a highly structured technique that is usually applied to a complex item of mechanical or electrical equipment. The overall system is described as a set of sub-systems and each of these as a set of smaller sub-systems down to component level. Individual system, sub-system and component failures are systematically analysed to identify their causes (which are failures at the next lower-level system), and to determine their possible outcomes, which are potential causes of failure in the next higher-level system. This technique is quite specialised and usually requires expert assistance. In case at hand if a certain parameter goes above the maximum target value, changes would occur to ensure the set value is maintained. In so doing the values would be found within the range of maximum and minimum value. This can therefore be found in areas of specializations like agricultural, medicine and nursing, motor vehicle industry, real estate amongst other fields (Mondie 2005; Shah & macGregor 2005). function Potential failure mode Potential effects (s) of failure Potential cause (s) of failure Current process controls Recommended Action(s) Action taken Tank leaks leaks Cause fire Poor maintained tanks Inspection Repair Overheating Too much heat Increase pressure Unchecked power supply verification Automate power supply Pressure Overpressure Blast Unchecked pressure None None Control pressure valve Faulty and leads leakage Old valves and unmaintained Blast Overheating and high pressure Loss life and property Several factors affecting the controller performance have been deduced together with their specific effects though in most cases these would be changed to ensure maximum results. The performance factor (bandwidth, voltage, time span, and channel diameter, power supply speed/velocity and flow rate at Best Efficiency Point is a good indicator of how regulate able parameters influences controller process’ performance (Richardson 2004). When such deviations are insignificant then their effect would not produce any noticeable effects on the controller function. A good example would involve a more specialized system does the supervision as well as data acquisition, this is the supervisory and data acquisition abbreviated as SCADA (Zhang 2010). This system has been applied in areas like power plants, distribution of natural gas and supply of water pipelines. These areas would require a system that can ensure remote data are gathered within a low bandwidth that has an intermittent variation. The system uses an open loop control. Its remote terminal units would ensure that the supervisory data are send back to its control stations. Such systems must be integrated with a computer to rely the data that can be interpreted by the in build software. Such controlled processes have not only made some work easier to manage and get a real time results but has also saved a lot on several modalities that would have complicated the entire process and hence increasing the applicable cost of running very simple processes (Grimble 2006; Lewin et al. 2002; Zhang 2010). Event tree for this process using overpressure as top event Event Detection Shutdown /release Evacuation Outcome From the event tree above it can be noted that when there is overpressure that is detected earlier and the pressure is released or pipe system shut down there is no evacuation or thus no risk associated with it. However when detected earlier but pressure release or shut down fails then evacuation takes place. When evacuation is on time, there is no risk but property is destroyed. Lastly, when there is late detection, only evacuation will take place since we may not have time for shutdown or release of pressure. In this case there will be risk to property but exposure to human will depend on the degree of evacuation as shown in the tree above. d). The decision has been made to achieve adequate safely by ensuring that the equipment under control (EUC) is suitably safe A risk graph method according to IEC 61508 to establishing the required safety integrity level (SIL) value of the EUC sub-system is where risk is assumed to occur when there is no safety systems and compared to frequency of the hazardous event for such area and its impact. The following formula is derived for it Risk for unprotected area = F X C Where F is hazardous event frequency for areas with no safety-related systems in place and C is the consequences of the hazardous event Overheating of the mixture at the heat exchanger leads to rupture and subsequent fire, with the potential for a fatality, using the risk graph method, what is the SIL value for the temperature indicator controller, which is providing a continuous mode safety function. CONCLUSION The hazard analysis based on a checklist was used to do the risk assessment system. The methodology calculates the accurate probability for the frequency and magnitude of the occurrence of loss events. There are 4 stages in the methodology like Stage 1 – Identify scenario components, Stage 2 – Evaluate Loss Event Frequency (LEF), Stage 3 – Evaluate Probable Loss Magnitude (PLM), Stage 4 – Derive and articulate Risk. In Stage 1 the parameters that were at risk were classified and ranked based on their weights. In Stage 2, an evaluation of Loss Event Frequency (LEF) was made by estimating the Threat Event Frequency (TEF) and the capability of the threats were evaluated as Very High (VH), High (H)and Very Low (VL) respectively. The most likely result of a threat event is known as a Probable Loss Magnitude (PLM) and in Stage 3, the PLM was evaluated besides determining the worst-case loss and the estimated probable loss. The worst case loss was evaluated as High (H) for all the 5 threat actions The worst case loss was evaluated as Severe (SV) for all the 5 threat actions and 6 loss forms for the R & D database from the 3 threat communities because the loss would affect RWW severely to the point of going out of business. This is because most companies invest heavily in R & D and RWW is no exception and if hackers, viruses or malicious individual employees cause damage, then it would affect the ability of RWW to do business. In stage 4, the risk assessment is done based on LEF, PLM and Worst-Case Loss Magnitudes (WCLM). Reference List Dale, RP & Fardo SW 2009, Industrial process control systems, Fairmont Press, Inc, Boca Raton USA. Grimble, MJ 2006, Robust Industrial Control Systems; optimal design approach for polynomial systems, John Willey & Sons, Ltd, Chichester England. Lewin, DR, Seider WD, Seade, JD 2002, ‘Integrated process design instruction’, Computers and Chemical Engineering, vol. 26, no.2, pp. 295-306. Mondie, S (ed.) 2005, System, structure and control 2004, Elsevier-IFAC, Oxford-UK. Richardson, P (ed.) 2004, Improving the thermal processing of foods, Woodhead publishing ltd, Cambridge- England. Shah, LS & MacGregor, F. J. (ed.) 2005, Dynamics and control of process systems 2004, Elsevier-IFAC; Oxford UK. Zhang, P 2010, Advanced Industrial Control Technology, Elsevier, Oxford UK. Read More