Hazard and Operability (HAZOP) is a well-known and well documented study. HAZOP is used as part of a Quantitative Risk Assessment (QRA) or as a standalone analysis. The purpose of the HAZOP is to investigate how the system or plant deviate from the design intent and create risk for personnel and equipment and operability problems. HAZOP studies have been used with great success within the Chemical and Oil & Gas industry to obtain safer, more efficient and more reliable plants.
The HAZOP concept is to review the plant in a series of meetings, during which a multidisciplinary team methodically "brainstorms" the plant design, following the structure provided by the guide words and the team leader's experience. The primary advantage of this brainstorming is that it stimulates creativity and generates ideas. This creativity results from the interaction of the team and their diverse backgrounds. Consequently, the process requires that all team members participate (quantity breeds quality in this case), and team members must refrain from criticizing each other to the point that members hesitate to suggest ideas. The team focuses on specific points of the design (called "study nodes"), one at a time. At each of these study nodes, deviations in the process parameters are examined using the guide words. The guide words are used to ensure that the design is explored in every conceivable way.
Thus, the team must identify a fairly large number of deviations, each of which must then be considered so that their potential causes and consequences can be identified. The best time to conduct a HAZOP is when the design is fairly firm. At this point, the design is well enough defined to allow meaningful answers to the questions raised in the HAZOP process. Also, at this point it is still possible to change the design without a major cost. However, HAZOPs can be done at any stage after the design is nearly firm. For example, many older plants are upgrading their control and instrumentation systems.
The success or failure of the HAZOP depends on several factors:
- The completeness and accuracy of drawings and other data used as a basis for the study.
- The technical skills and insights of the team.
- The ability of the team to use the approach as an aid to their imagination in visualizing deviations, causes, and consequences.
- The ability of the team to concentrate on the more serious hazards which are identified.
Quantitative Risk Assessment (QRA) is a formal and systematic risk analysis approach to quantifying the risks associated with the operation of an engineering process. A QRA is an essential tool to support the understanding of exposure of risk to employees, the environment, company assets and its reputation. A QRA also helps to make cost effective decisions and manages the risks for the entire asset lifecycle. A quantitative assessment is a risk analysis performed with a focus on numerical values of the risks present. The quantitative risk analysis allows you to determine the potential risk of a project. This can help you decide if a project is worth pursuing. It also is useful in the development of project management plans, as understanding the risks present allows you to reduce the likelihood of certain risks and to prepare for others that you cannot fully eliminate.
- To identify the hazards associated with a facility
- To determine the potential frequencies and consequences of the identified hazards
- To determine the system availability of the protection systems
- To quantify the risks associated with a facility (e.g., Risk Contours, Individual Risk Per Annum (IRPA), Potential Loss of Life (PLL) and F-N Plots)
A typical QRA study conducted by a QRA Consultants consists of the following processes:
- A consequence analysis to determine the consequences of the hazardous release from a facility (including flammable, explosion and toxic). The consequence analysis is carried out with the use of the Det Norske Veritas (DNV) Process Hazard Analysis Software Tool (PHAST) software.
- An Impact Analysis to determine the frequency of a specific hazardous impact using Event Tree Analysis (ETA). ETAs are ‘bottom up’ analytical tree diagrams that determine the overall likelihood of a particular impact following a hazardous release (i.e., Jet Fire, Flash Fire Vapour Cloud Explosion (VCE)).
- A Risk Assessment conducted using DNV PHAST Risk software to determine the risks associated with hazardous scenarios.
- Risk Reduction Measures to identify the options to reduce or mitigate the risks.
- Lifecycle Cost Analysis to provide a Cost Benefit Analysis (CBA) based on different risk mitigation measures.
Receipt of petroleum products
At present IOCL Gwalior Depot receives MS/HSD/SKO by Railway Tank wagon from Mathura Refinery or any other TW loading location mostly and Ethanol by road tankers. Sometimes, it receives product through Tank Trucks also. The railway unloading siding is common for all the three companies and BPCL is railway siding coordinator and BPCL being Railway siding coordinator maintains the Railway siding in respect of all facilities including maintenance of firefighting equipment. Fire Water supplies to Railway siding is taken care rotationally by each company at the interval of one month.
Details of the existing storage tanks and the new tanks proposed for facility augmentation are provided in Table. All storage tanks are placed in four Dykes details of which is enumerated below:
Details of Storage Tanks
|TAG NO.||PRODUCT STORED||TANK DIMENSIONS DIAMETER X HEIGHT (M)||TANK CAPACITY (KL)||TANK TYPE|
|Dyke 1 (Existing)|
|T001||HSD||14 x 20||2919.32||Cone roof tank|
|T002||HSD||12 x 18||1932.6||Cone roof tank|
|T003||HSD||12 x 18||1925.6||Cone roof tank|
|T004||SKO||14 x 20||2899.7||Cone roof tank|
|T005||MS||14 x 20||2899.8||IFR Tank with Dome Roof|
|T006||MS||10 x 9||491.8||IFR Tank with Dome Roof|
|T007||MS||10 x 9||491.5||IFR Tank with Dome Roof|
|T012||MS||12x9||710.3||IFR Tank with Dome Roof|
|Dyke 2 (Existing)|
|T013||HSD||20 x 14||4172.3||Cone roof tank|
|T014||HSD||20 x 14||4172.8||Cone roof tank|
|T017||MS||16 x 12||1861.94||IFR Tank with Dome Roof|
|T016||Ethanol||3x10.5||70||U/G Horizontal Tank|
|T018||Ron booster||2.11x6.25||20||U/G Horizontal Tank|
|TAG NO.||PRODUCT STORED||TANK DIMENSIONS DIAMETER X LENGTH (M)||TANK CAPACITY (KL)||TANK TYPE|
|T015||Ethanol||4.12x15.9||200||Horizontal A/G Tank|
Petroleum products receipt
All products such as; MS, HSD, SKO except Ethanol are received by Railway Tank wagon rake being placed in railway unloading siding which is located near Depot boundary. In addition to the above, Ethanol is received through tank trucks.
Petroleum products dispatch
There are two TLF gantries of 9+2 have been provided for loading of all products. It operates in general shift only. There is manifold arrangement in product pump house for loading of the products to the TLF gantries. There are 2 no of pumps for MS, 2 no of pumps for HSD, 2 no of pumps of SKO and 3 no of pump of Ethanol.
Petroleum Products receipt
All products except Ethanol is received by Rail Tank Wagon and two no of pumps installed for each product except Ethanol in same product pump house.