detectie flacara zona rezervoare.pdf

Gas and fire detection in a tankage area A new detection system in a refinery’s tankage area has transformed the level of safety in the event of gas leakage and fire NÍYAZÍ BOZKURT Tüpraş Kirikkale Refinery 

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state of the art gas and re detection system has  been installed in Turkish T urkish Petroleum Reneries’ (Tüpraş) Kirikkale Renery. The purpose of the system is to detect both re and gas leak ages across the entire tankage area. The detection system is  based mainly on hydrocarbon gases, so most of the detectors are of the hydrocarbon type and calibrated with reference gases. Furthermore, ame, hydrogen, hydrogen sulphide and linear heat detectors are located wherever appropriate. In total, there are 169 hydrocar  bon (HC) detectors, two hydrogen sulphide detectors, 49 ame detectors, one hydrohydro gen detector, and seven linear heat detectors. In the rst step of the instalinstal lation of the detection system, the tankage area was divided into eight separate segments. The criteria for establishing this separation of the sectors is the area, and the distance between tanks and detectors. The main objective of the system is to detect both re and gas leakages in the tank age area. All of the tanks have

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Figure 1 Overview of tankage area

at least one hydrocarbon detec tor at their entry or exit points. Besides the tanks, there are four pumping stations to be considered. Flame detectors have been placed at high points on the pumping stations. The most important function of the system is to make operators aware of any liquid leakage around the dyke of the tanks. Hydrocarbon detectors help the system to do this. Linear heat detection (LHD) systems are installed on the surface of oating roof tanks.

Seven linear heat detectors are positioned on the system.

Division of the tankage area into regions The tankage area has been separated into smaller sections, or regions, for better control of the system. In each of these regions, alerting ash lamps and horns are installed. When the detectors of a region sense a gas escape, the ash lamps and horns are activated. An overview of the tankage area can be seen in Figure 1. As indicated, it is divided into

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Naming detectors

Figure 2 Detail of a tankage region

many smaller areas. ame detectors in the LPG The main criterion for deterdeter - tanks area. mining the area of each of Hydrogen sulphide detectors these divisions is the number are located in the control room of detectors required within it.  buildings, close to the ground. detec Figure 2 shows a more detailed Furthermore, hydrogen detecoverview of an individual tors are positioned in the region. higher parts of electrical substations. How to locate detectors To summarise, detectors are The locations of the detectors located according to their are decided according to differdiffer - distance from potential exploexplo ent criteria for pumping sion points and the molecular stations and tankage areas, but weight of the gas each detector the main criterion for positionposition - is designed to detect. If the ing any detector is for it to be molecular weight of the senssens close to a potential explosion ing gas is higher than the point. molecular weight of air, the Detectors are located at the detector is positioned close to entry and exit points of tanks the ground. In other circumcircum since leakages tend to occur stances, the detectors are where pumps and other equipequip - located in high positions. ment that handle materials entering and leaving the tanks Junction Remote input are located. Field box Out (RIO) panel Flame detectors are posiposi tioned in the tankage area’s four pumping stations, taking into account items of critical Control Room equipment. The ame detectors are placed on high platforms to  broaden the area each detector observes. In addition, there are Figure 3 Carrying the signal to the DCS

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Each detector is named accordaccord ing to the type of gas it senses and the tankage or pumping station number where it is posi tioned. The name of a detector  begins with the name of the tankage or pump station and continues with an abbreviation of the detector type, such as hydrocarbon (HCD), hydrogen sulphide (HSD), ame (FLD), and LHD. Finally, the number of detectors present in a loca tion is added to the name. An example of nomenclature for several detectors is: 4101- HCD- 001: Tank 4101 rst hydrocarbon detector 3160- HSD- 001: 3160 Building rst hydrogen sulphide detector 3100- FLD- 009: 3100 Pump station ninth ame detector 4218- LHD- 001: Tank 4218 linear heat detector

Carrying signals to the DCS All detector signalling devices are connected to a control  board via gas detection detection system (GDS) panels. Detector signals are carried to junction boxes via 3X2.5 armored instrument cables. In the junction boxes, these signals are jointed and carried by main cables to the control board. If the distance  between  between a junction junction box and the control board is not too far, the  junction  junction box’s main cables are connected directly to the control board. Remote input-output (RIO) panels are employed as gas detection system panels in the eld. The reason for using RIO is the relatively long distances  between  between the detectors detectors and the control board. Communication  between  between RIO and GDS is achieved by Modbus which is

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faster and safer at carrying long distance signal applications. The signals combined in GDS are sent to DCS via instrument cables. A connection diagram of the system is shown in Figure 3.

System redundancy The system is redundant in  both the GDS and the DCS panels. A GDS panel sends the duplicated data with separate cards. There is no connection  between these two communica communica tion cards. In the DCS, there are two redundant Modbus cards: the master and the slave. Each card receives signals from separate GDS communication cards. The master DCS card scans the eld and accepts data from the GDS panel. If there is any fault in the master DCS card receiving data from the eld, the slave DCS card begins to accept data from the other GDS communi cation card.

LHD terminology LHD becomes compulsory as the risk of re increases above tanks. LHD terminology is  based on resistance change in an electrical cable. As the amount of heat increases, there is an increase in resistance caused by the length of the cable. The main leakage points for tanks are seals. LHD cable is located close to the seals. At Tüpraş, we have applied LHD systems to oating roof tanks. LHD cable is placed close to the second seal and moves as the roof of the tank moves. There are special mechanisms to protect the cable from mechanical damage during such movement.

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Sprinkler systems

Conclusion

There are two sprinkler In this article, the main points systems in the tankage area: of the gas and re detection one in the marker building and system in the tankage area of the other in the LPG tanks Tüpraş Kirikkale Renery have region. The philosophy is simisimi -  been introduced. The system lar in both systems. Flame cost million dollars to install and hydrocarbon detectors are and is unique. connected to the sprinkler With the help of this new systems. If there is an alarm in system, the tankage area is any ame detector, the sprinsprin - safer than before and its instalinstal kler system activates. lation was considered Furthermore, when there are compulsory in view of the risk alarms in any two hydrocarbon of re and gas leakages. The detectors, the sprinkler system system is used efciently by is similarly activated. the tankage area’s unit operaopera tion team, and different types Alternatives and improvements of detector in the system The main alternative to the include ame, hydrocarbon, system established by Tüpraş hydrogen sulphide, linear heat is to use wireless detectors. An and hydrogen. advantage of a wireless system is avoiding the need for underunder - References ground cable trenches. 1 Turkish Petroleum Refineries, Kirikkale/ Installation of some parts of Turkey, Experiences. the system has been difcult 2 h t t p : / / l i f e s a f e t y m a g a z i n e .  because of the need to dig up com/2009/11/guidelines-top-fivethings-to-know-about-heat-detectors/ thousands of metres of ground. 3 www.gmigasandflame.com/articles. Wireless detectors are thus html easier to maintain. The chief disadvantage of a wireless Níyazí Bozkurt  is Instrumentation system is that the detectors are Chief Engineer in the Projects and open to possible noise and Investment Department of Turkish Petroleum Refineries’ Kirikkale Refinery, other disturbances. We could also improve the where he has managed various types of instrumentation and electrical projects. system by adding more hydrohydro - His previous role was Advanced Process gen sulphide detectors close to Control Engineer, where he established the tanks. many process control techniques for

Manual call point The manual call point (MCP) is a manually activated compocompo nent of the gas detection system. It is used if there is any leakage or re and the autoauto mated system is not activated. In other words, it helps the system to warn operators when any alarm situation arises outside the scope of the detec tion system.

different units. He holds degrees from the electrical and electronics engineering departments of Middle East Technical University, Ankara,Turkey.

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