Fire hazard in a refinery
Introduction
A refinery is an industrial plant that converts crude materials into finished products. In this respect, an oil refinery is an industrial plant that converts crude oil into its constituent products that range from petrol to paraffin. Operations in an oil refinery can be grouped into marketing, refining and production. Production entails the process of locating, drilling and pumping oil out of the wells as well as pre-treating crude oil once it is pumped out of the well. Refining, on the other hand, entails conversion of crude oil into salable products whereas marketing involves distribution and the sale of finished products from the oil (Cheremisinoff 84). The focus of this report will be on refining, which in most cases is vulnerable to fire due to its operations.
Given the nature of materials used in a refinery, a refinery is a very risky area. It is vulnerable to both fire and explosion because of the chemical composition of materials used and products produced. Generally speaking, almost all products produced in a refinery are flammable. They are also volatile meaning that their volatility level is very high. Consequently, when fire comes near them, they detonate or catch fire easily. On the other hand, almost all materials used in a refinery are also flammable. They are also toxic and for the same reasons, they catch fire easily and detonate effortlessly. As a result, if people working in refineries are not cautious, they might cause fire or explosion. This might cause a lot of harm to both the people and refineries (Klerk 493). In this regard, personnel working in refineries especially those concerned with fire protection should familiarize themselves with the general principles of combustion. Otherwise, they are likely to be caught unaware when explosions occur or when refineries catch fire.
For a fire to start scientifically, three components namely oxygen, heat and fuel must combine together. Oxygen comes from the air meaning that it is readily available. Fuel, on the other hand, is readily available in a refinery. As a result, unless cautious measures are taken to prevent heat from mixing with fuel present in the refinery, fire is likely to start easily. Basically, fire starts after oxygen mixed with fuel is subjected to heat. Heat is required to convert liquid fuel in a refinery into gaseous form. Although chemical reaction might be termed as the fourth component, it only sustains fire once it starts. All these components except heat are readily available in refineries. Consequently, it is the responsibility of those working in refineries to restrain heat or conditions that might give rise to heat from coming near refineries. Otherwise, fire is likely to start anytime there is sufficient heat in a refinery to cause combustion. This notwithstanding, most fires at refineries occur due to leakage of hydrocarbons into the atmosphere. When such leakages occur, oxygen present in the air facilitates combustion so long as there is heat to trigger combustion (Fahim, Al-Sahhaf and Elkilani 358). Based on this understanding, fire and explosion in refineries can be minimized by limit leakage of hydrocarbons into the air and limiting sources of ignition in refineries.
Two of the main inherent hazards associated with fire are smoke and thermal radiation. Others include boilover, BLEVE and deliberate ignition. Boilover is a sudden ejection or overflow of contents contained in a storage tank due to heat waves reaching the tank (Klinoff 404). Under extreme conditions, flammable liquids expelled from storage tanks might cause serious injuries to surrounding areas. BLEVE, which stands for boiling liquid expanding vapor explosion, is an explosion that results when a container bursts into pieces following high temperatures. Deliberate ignitions are fire explosions that result from deliberate actions. Damages due to fire and explosions in refineries result to loss of money, properties and lives. The case study below is a good example of possible consequences of fire in a refinery even though no life was lost in it.
This report is a cause-effect report. The first part starts with a case study that highlights some human actions that might result to fire in a refinery. The second part focuses its attention on some precautionary measures that might minimize fire and explosion incidences in refineries. The third part highlights some EHS guidelines for refineries while the fourth part concludes the report with a recap of the main points.
Case study
As an illustration of what might happen to a refinery if precautionary measures are not implemented as they ought to be implemented let us look at a Ciniza refinery case study. This refinery is a subsidiary of Giant industries. The refinery caught fire in 2004 due to the company’s as well as employees’ negligence. The incident occurred in the refinery’s hydrofluoric acid’s unit where isobutane and olefin feedstock are combined together before being mixed with hydrofluoric acid to produce alkylate. Although hydrofluoric acid is used widely in oil refineries, it is highly corrosive, toxic and hazardous thereby when used in alkylation process; it ought to be handled with a lot of care (Fahim, Al-Sahhaf and Elkilani 359).
A day before the incident occurred, the refinery’s operator had attempted to conduct a regular schedule on alkylate recirculation pump. This pump had a scheduled switch because its seal had recurrent problems. The scheduled switch was intended to stop the seal from malfunctioning. During the regular schedule, the primary electric pump was supposed to be taken out and steam-driven pump to be turned on to run the refinery. In the process of doing this, the operator found out that the spare pump was not able to rotate. As a result of this, the following morning two mechanics both specialists in their areas of expertise were assigned by refinery’s supervisor to repair the seal. In so doing, the supervisor prepared the work permit for the two mechanics. The work permit outlined the safeguards required for the repair as well as the work to be done (U.S CSHIB 3).
As it was found out after the incidence, quarter plug valve was used to isolate the maintenance pump. This plug was used primarily for turning the pump on and off. It was also used for some throttling services. The valve wrench was used to open or close the plug valve. A quarter turn of the valve blocked the flow path. During the maintenance process, the operator depended solely on the valve wrench to establish that suction valve was open. In doing so, he moved the wrench to where he believed was the closing position. Investigations after the incidence indicated that some operators too depended on the wrench position to do the same rather than depending on the flow. In order to repair the pump, the two mechanics that were assigned this task were supposed to disassemble the pump from the rear pump housing assembly, remove impeller and take it back to manufacturer for repair. Before one of the mechanics left the alkylation unit to obtain the tools that were supposed to remove the pump, he noticed that the position of the valve showed that the suction valve body was open. However, he did not confirm what he observed from his colleague (U.S CSHIB 3).
While the mechanic went to obtain the tools, the plant operator on the other hand was busy placing locks and tags on the discharge and suction valves to show that they had been closed as well as prevent them from inadvertent opening. The other mechanic too did as the operator did. When the mechanic that had gone for the tools returned, he was informed by his colleague that the valves were closed, tagged and secured as per the facility’s procedures; thus, they could remove the pump. Although the two mechanics agreed that the pump was closed, neither of them had seen the refinery’s operator close the valve. They both believed that the pump was closed because the operator had affixed the tags and the wrench valve for opening and closing the pump was placed perpendicular to the flow.
To verify that no pressure was coming from the pump, the operator disconnected the vent hose of the pump. In contrast to manufacturer’s instructions, the operator did not use the low point drain plug to check the pressure because this plug did not have a valve to isolate it from pressure line. The minute the hose was uncoupled, only a small amount of alkylate flowed before it stopped a few seconds later. This led the mechanics and operator into believing that the pump had been de-pressured as per manufacturer’s instructions. Consequently, they concluded that the pump was ready for removal, which was not the case because they had not de-pressured the pump and the vent line was still plugged.
Upon making the above assumptions without verifying them, they proceeded to removing the pump. However, as soon as they separated the pump case from the flange, alkylate was released and it produced a roaring sound in the refinery. One of the mechanic was blown by alkylate over an adjacent pump. Luckily, he only suffered some broken ribs. The eyes of the other mechanic were splashed with dust. So he ran to an eyewash station to wash his face. After washing his face, he exited the alkylation unit. Unfortunately, the alkylate that covered his clothes caught fire that burnt his body seriously. The fire from mechanic’s clothes spread to other parts of the refinery such that within less than a minute there were explosions in the refinery.
The refinery’s safety officer who was about 150 yards from the refinery at the time of explosion rushed to the refinery. As he was trying to minimize the effect of the explosion by turning the fire monitors on, he was attacked by the fire and suffered minor injuries (U.S CSHIB 5). Two other workers in the refinery suffered minor injuries as well. In total, six employees were injured in the incident with four of them being hospitalized with serious injuries. Although no one lost his/her life during the incidence, the alkylation unit and other neighboring units were damaged severely.
A review of the incidence after the accident occurred indicated that the pump had a history of failures. The failures were twenty-three in total with most of them being seal related and pump seizure related. Although the company’s integrity program was mandated with monitoring these failures, it did not do enough to prevent the failures because plugging materials were found in the pump’s discharge line, pump housing as well as in the impeller. This indicates that the causes of major breakdown in the refinery were not identified and rectified before they occurred. Instead, they were rectified when they occurred or after they caused damages as they did on the fateful day. From a mechanical integrity perspective, the case study is a good example of breakdown maintenance (U.S CSHIB 5).
Safety precaution
This part of the essay evaluates some safety precautionary measures that should be observed in a refinery. These measures are aimed at minimizing fire outbreaks and explosions in refineries. To start with, all employees in a refinery are supposed to wear clothes that suit their jobs. Such clothes should meet the following minimum conditions among other conditions. First, they should not be flammable meaning that they should not catch fire easily. Some of the flammable clothes that should not be worn in a refinery include nylon, Dacron, acrylic and mixes. In contrast, employees and other people working or visiting refinery should wear fire resistant clothes. Fire resistant clothes are clothes that do not catch fire easily unless contaminated with flammable substances. Such clothes include cotton, proban and nomex.
Second, if clothes become saturated with oil or any other flammable substance, they should be removed immediately. This precautionary measure helps minimize fire incidences in a refinery and protects skin from irritation. Third, employees working with machines should wear gloves to protect themselves from hand injuries. Fourth, they should not wear loose clothes that do not fit their bodies. In addition, they should not wear neckties or ragged clothes when working near rotating machines. Fifth, employees should wear long-sleeved shirts and blouses with full-length overalls.
In order to protect head injuries, employees should wear hats and security glasses. Hats protect head generally whereas security glasses protect eyes from injuries. Nobody should be allowed to smoking within the refinery. However, smoking should be permitted in designated areas that do not pose any danger to the refinery. Such areas should have ashtrays and be kept neat all the time. Anybody wishing to smoke should go these areas for smoking and should comply with smoking policies as outlined within the refinery. As a precautionary measure, people walking within refineries including employees should not carry match boxes with them.
EHS guidelines
The environmental health and safety (EHS) guidelines are sets of technical reference principles used in various industries to guide practices in those industries. They outline what actors in various sectors should do as they handle hazardous materials and conduct other businesses (IFC 1). This part of the report highlights various aspects as they relate to oil refineries with an aim of demonstrating how various issues should be handled in these refineries.
Risk analysis
The first issue highlighted in this report is risk analysis. This aspect forms an important part of oil refineries because these refineries are prone many risks. The EHS guidelines recommend that risk analysis should be conducted to ascertain the most probable risk in a refinery. As per the guidelines, risk analysis should start with identification of possible risks within a refinery. Once those risks have been identified, they should be analyzed so that their impacts can be understood. Upon analyzing these risks, measures should be established to mitigate those risks.
Employee training
The EHS guidelines recommend that employees should be trained how to manage hazardous materials so that they can be prepared to handle chemical hazards at their places of work. According to the guidelines, trainings should focus their attention on hazard identification, safe work practices and the best methods of handling hazardous materials. They should also focus their attention on special hazards that are unique to employees’ jobs as well as basic emergency procedures. The guidelines recommend that a list of employees attending any training should be kept safely for future reference. They also recommend that training objectives should be developed together with the mechanisms to be used to achieve those objectives. Refresher courses should be conducted regularly with new recruits receiving training as soon as they join refineries. Employees should also be trained how to follow refiner procedures as well as work permit processes so that they do not violate these procedures (IFC 42).
Safe transport and management system
In order to enhance safe transportation and management of hazardous materials, the EHS guidelines recommends that when transporting these materials within buildings, transportation should be done by walking. In case of indoor corridors connecting buildings, the person transporting these materials should use corridors. The guidelines also recommend that small containers used to transport these materials should be put inside secondary containers so that transportation can be efficient. Secondary containers placed on carts as well as buckets should be used to transport large containers carrying these materials. Whenever transportation takes place outdoor, carts with pneumatic tires as well as clean-up kits should be used to transport large containers.
For the DOT-approved containers that do not require secondary containers, metal cans should be transported on carts, gas cylinders on cylinder carts whereas liquid nitrogen Dewars should be transported on stable rollers or on carts (IFC 40). The guidelines further recommend that one should move carefully on uneven terrains as well as around corners. Above all, transportation of hazardous materials should comply with regulations provided by various bodies such as IATA and EHS.
Handling and storage of hazardous materials
Under normal circumstance, an oil refinery company manufactures and uses considerable amounts of hazardous materials. At times, it also stores considerable amount of hazardous materials. These materials include by-products, intermediate products as well as raw materials. Because of their chemical and physical characteristics, these materials pose considerable risks to human beings. As a result, they should be handled with a lot of care. In order to avoid fire when handling these materials, the EHS guidelines provide the following. First, these materials should be stored in separate areas that are free from fire. Second, the most hazardous materials should be stored in separate rooms to avoid them coming into contact with the less hazardous ones.
Third, if it is not possible to separate these materials, structures should be erected to separate the two. The physical separation should be aimed at helping avoid spill, explosion and fire as well as other emergency situations that might affect the stores. Fourth, all forms of ignition should be avoided near flammable stores. Fifth, construction materials used to construct the stores should be selected carefully. This minimizes explosion by ensuring that explosive materials are not used to construct the stores. Sixth, re-usage of tanks and storage materials with different products should be avoided under all cost.
Emergency planning
Whenever handling hazardous materials, the EHS guidelines recommend that one should be prepared for any eventuality. In this response, they recommend that procedures and practices should be developed beforehand so that quick and efficient methods for responding to emergencies can be developed. As per the guidelines, the response plan should focus its attention on the following items. First, it should focus its attention on planning coordination so that safety personnel can be prepared to inform the members of the public about the emergency, document first aid response strategy and keep emergency response plan updated. Second, it should focus its attention on emergency equipments so that procedures can be laid down to help keep these equipments ready for any eventuality (IFC 38). Third, the response plan should train employees how to respond to emergencies. If need be, the members of the community should also be involved in emergency planning. They should be provided with general information regarding possible emergencies, effects of the hazardous materials and safety measures to protect them from unintended eventualities.
Tank cleaning
Tank cleaning is a hazardous practice. As such, it should be conducted with a lot of care. The EHS guidelines recommend that the exercise should be conducted cautiously to avoid contamination that might result to explosion.
Alkyl unit
In a crude oil refinery, some liquid hydrocarbons are run to gasoline blending plant directly whereas others go through alkylation process. In alkylation process, the light hydrocarbons are combined together using either sulphuric acid or hydrofluoric acid. The main hazard from this process might come from the two acids, residues, byproducts or dust. Because the two acids used in this unit are very hazardous, they should be handled with a lot of care. In this respect, during the cleaning or maintenance process, the acids should not come into contact with water because such contact might result to explosion.
Conclusion
This study has evaluated the causes and damages of fire in oil refineries. It established that although many factors might cause fire in these refineries, human factor is a major factor in this area. Scientifically, the report established that fire starts when oxygen combines together with fuel in presence of heat. As a precautionary measure, the report recommended that refinery employees should minimize actions that might produce heat that can cause combustion. In order to minimize fire outbreaks and explosions within refineries, the report recommended that refinery employees should wear less flammable clothes such as cotton and nomex. The report also recommended that employees should not smoke within refineries or carry match boxes with them. More importantly, those tasked with safety measures in refineries should be alert all the times. As illustrated by the case study, they should not make assumptions when dealing with safety issues. Instead, they should follow instructions to the letter as directed by manufacturers’ manuals. At the same time, refinery employees should observe EHS guidelines when handling hazardous materials.
Work cited
Cheremisinoff, Nicholas. Practical guide to industrial safety: methods for process safety professionals. New York: CRC press, 2000. Print.
Fahim, Mohamed, Al-Sahhaf, Taher, and Elkilani Amal. Fundamentals of petroleum refining. Amsterdam, London: Elsevier science, 2010. Print.
IFC. Environmental, health, and safety general guidelines. Web. 18th July, 2016.
Klerk, Arno . Fischer-tropsch Refining. Weinheim: Wiley-VCH, 2011. Print.
Klinoff, Robert. Introduction to fire protection and emergency services. Boca Raton: Jones & Barlett publishers, 2013. Print.
U.S chemical safety and hazard investigation board [U.S CSHIB]. Oil refinery fire and explosion. Web. 18th July, 2016. http://www.csb.gov/assets/1/19/Giant_Case_Study.pdf