Health and Safety in Cyclohexane Manufacturing - Coursework Example

Health and Safety in Cyclohexane Manufacturing Introduction: Cyclohexane is an organic compound with the chemical formula C (6) H (12). It is a colourless liquid that has a mild and sweet odour that is similar to that of chloroform and benzene (OCCUPATIONAL SAFETY AND HEALTH GUIDELINE FOR CYCLOHEXANE). Background: It is a commercially important chemical with several industrial uses that include use as a solvent for dissolving cellulose ethers, lacquers, resins, fats, waxes, oils, bitumen and crude rubber. It is also used in the manufacturing industry for perfume manufacturing, surface coating operations employing lacquers, synthesis of adipic acid in the manufacture of nylon, synthesis of caprolactum and in the extraction of essential oils. Its multi-industrial use has led to large scale manufacturing of cyclohexane. However, exposure to cyclohexane during its manufacture poses health hazards, leading to concerns on this aspect in the manufacture of cyclohexane (Cyclohexane fact sheet). Another factor of concern in the manufacture of cyclohexane is that cyclohexane is highly inflammable. The flammability rating assigned to cyclohexane by the National Fire Protection Council is 3, which means it poses a serious fire hazard. (OCCUPATIONAL SAFETY AND HEALTH GUIDELINE FOR CYCLOHEXANE).Thus health and safety hazards pose problems in the manufacture of cyclohexane. Manufacturing Process of Cyclohexane: Fractional distillation of naphtha was the traditional manufacturing process for cyclohexane. This process was difficult and inefficient, as there were several components of naphtha with a similar boiling point as cyclohexane. This led to the bulk of commercial production shifting to the simpler and highly efficient manufacturing process for cyclohexane, which is the catalytic hydrogenation of benzene, employing either liquid or vapour based methods in the presence of a highly dispersed catalyst or the catalyst in a catalytic fixed bed (Cyclohexane (CX) Production and Manufacturing Process). The manufacturing process for high purity cyclohexane involves the hydrogenation of benzene at high temperatures of 400-500 degrees Fahrenheit under high pressure of 500 psig. This hydrogenation of high purity benzene is carried out in adiabatic reactors using a supported platinum catalyst. The reaction is highly exothermic, which calls for external cooling to control the heat liberated during the reaction. The effluent of the final reactor is cooled to 100 degrees Fahrenheit prior to transporting to a separator drum. Refrigeration is used to remove cyclohexane in the vapour from the drum prior to the gas being split to make up a recycle hydrogen stream and purge gas stream. Compression is applied to the recycle gas and mixed with makeup hydrogen. Since the mixture is caustic it is water washed to prevent sulphur build up. A part of the cyclohexane liquid from the separator drum is recycled to the reactors for the purpose of absorbing a part of the heat generated by the reaction. The balance of the separator liquid makes up the net production of cyclohexane, which is stabilized in a tray column, prior to being sent for storage (Cheremisinoff, 1998). Safety and Hazards in the Manufacture of Cyclohexane: The process materials used in the manufacture of cyclohexane are essentially hydrogen and benzene and the product of the process is cyclohexane. All three chemicals are inflammable with low flash points. For example the flash point of cyclohexane is -4 degrees Fahrenheit. In the process high pressure and high temperature is applied to the process materials. The process is highly exothermic. Thus in the process three highly inflammable gases are used in a high pressure and high temperature environment, which is further exacerbated by the heat generated from the highly exothermic reaction occurring in the process. The process materials and the product are either in gaseous form or in liquid form and transported via pipes during the various components involved till the final storage point. High pressure employed in the process has implications on the adiabatic reactors, whereby any faults in the reactors could lead to leaking of the chemicals into the environment. The piping includes bends, joints and valves, which are potential points of leak into an environment of heat much higher than the flash points of the chemicals used in the process. The risk of fire and explosion is high. Further controls are employed for regulating the various aspects of the process. Failure of the controls could lead to build up of pressure leading to leakage of any or all of the chemicals used in the process (Disaster of Chemical Plant at Flixborough). In addition to the safety hazards involved in the manufacture of cyclohexane, there are health hazards for the workers and those in the nearby vicinity on exposure to any leaked cyclohexane. The health hazards posed depends on the strength of cyclohexane involved in the exposure and the duration of the exposure. The range of health risks includes negative impact on the nervous system, headaches, numbness, tremors, convulsions, and damage to the eyes. These are the few known health risks, but all the health risks due to exposure to cyclohexane are still not known. Evaluations of the effects on the respiratory and reproductive systems are still going on (Cyclohexane fact sheet). Cyclohexane is detrimental to the surrounding environment too. It is highly resistant to bio-degradation and thus remains in the environment for a very long time in the environment. It is known to have acute toxicity to aquatic life. Its impact on birds and animals on the land are yet to be evaluated (Cyclohexane fact sheet). Minimizing Risks: Action to minimize risks to the workers starts prior to placing them in a potentially toxic environment. Workers need to be screened regarding the health status with particular emphasis on the respiratory system and skin. Workers also need to be educated about the health hazards involved. There should be a periodic medical evaluation of their health status to ascertain whether there is any development of reaction to cyclohexane exposure. The working environment has to be monitored frequently and regularly to determine the airborne exposure of cyclohexane by the workers. Personal protective clothing should be used by the workers after careful selection of the appropriate protective clothing, so as to prevent personal contact with cyclohexane. The appropriate protective clothing consists of gloves, sleeves, and encapsulating suits. The choice of appropriate personal protective equipment is based on the extent of potential exposure of the relevant worker to cyclohexane. The personal protective equipment needs to be periodically evaluated for determining the continued efficiency to prevent dermal contact of cyclohexane. At times it may be necessary for workers to be present in an environment that where the content of cyclohexane is above the prescribed exposure limits. In such instances it becomes necessary to provide the workers with respirators. Should there be any contact with cyclohexane, the affected areas should be thoroughly washed with plenty of water and then subsequently with soap and water. Safety showers and eyewash stations have to positioned, as close as possible to operations involving the handling of cyclohexane operations. Should a spill or leak of cyclohexane occur, then workers without protective gear should be allowed anywhere near the leak site or sites. Safety personnel are to be informed and all possible sources of heat and ignition removed from the site of leak. Storage of the cyclohexane produced should be in cool, dry, well-ventilated areas in tightly sealed containers and labelled appropriately. Any possible physical or chemical damage of the containers has to be avoided totally. Leaking of cyclohexane into the immediate vicinity of the manufacturing complex has to be avoided. In case of a leak the cause of the leak needs to be identified and the steps immediately taken to prevent any leak and the possible recurrence of it. The local authorities have to be informed so that adequate measures can be taken at the earliest to prevent exposure of the local population to cyclohexane (OCCUPATIONAL SAFETY AND HEALTH GUIDELINE FOR CYCLOHEXANE). Literary References Cheremisinoff, P. N. 1998, ‘Pressure Safety Design Practices for Refinery and Chemical Operations’, New York: William Andrew Inc. ‘Cyclohexane (CX) Production and Manufacturing Process’, ICIS, [Online] Available at: http://www.icis.com/V2/Chemicals/9075208/cyclohexane/process.html (Accessed March 2, 2008) ‘Cyclohexane fact sheet’, Department of the Environment and Water Resources, Australian Government [Online] Available at: http://www.npi.gov.au/database/substance-info/profiles/30.html (Accessed March 2, 2008). ‘Disaster of Chemical Plant at Flixborough’, Case Details, Failure Knowledge Database [Online] Available at: http://shippai.jst.go.jp/en/Detail?fn=0&id=CB1058048& (Accessed March 2, 2008). ‘OCCUPATIONAL SAFETY AND HEALTH GUIDELINE FOR CYCLOHEXANE’, Occupational Safety & Health Administration, U.S. Department of Labor [Online] Available at: http://www.osha.gov/SLTC/healthguidelines/cyclohexane/recognition.html (Accessed March 2, 2008) Read More