answer all (a) and (b)

a) The accident at Flixborough, England, occurred on a Saturday in June 1974. The Flixborough works of Nypro Limited was designed to produce 70,000 tons per year of caprolactam. The process uses cyclohexane, which has the properties similar to gasoline. Under the process operating conditions (155C,7.9atm), the cyclohexane volatilizes immediately when the depressurized to atmospheric condition. The process where the accident occurred consisted of six reactors in series. Reactor 5 was found leaking and hence, sent for repair. The feed pipes connecting the reactors were 28 inches in diameter. Because only 20 -inch pipe stock was available at the plant, the connections to reactor 4 and reactor 6 were made using flexible bellows-type piping. Bypass pipe section ruptured because of inadequate support and over flexing of the pipe section as a result of internal reactor pressure. Approximately 30 tons of cyclohexane volatized and formed large vapor cloud. The cloud was ignited by an unknown source an estimated 45 seconds after the release. Explosion destroyed the plant facility and office, 28 peoples died, and 36 others were injured. Damages extended to 1821 nearby houses and 167 shops and factories. The resulting fire in the plant burnt for over 10 days. Considering the case study described as above, i) Identify the accident sequence steps. (3 marks) ii) Develop the inherent safety procedure that could help to prevent or contain this accident. (4 marks) iii) Using layered accident investigation process; develop the underlying causes of the tank car loading explosion and give your recommendation. (3 marks) (b) Consider the household water supply system shown in Figure 4. Perform a hazard and operability (HAZOP) study on this system to improve the safety of the process. Select water supply (process parameters: flow), water tank (process parameters: flow and temperature) and water pump (process parameters: pressure) as study nodes. Figure 4: household water supply system (10 marks)