HAZOP STUDY OF HYDROGEN GENERATION UNIT OF A PETROLEUM REFINERY

Abstract

In the process industries there is often a probability for major accidents to happen. So it is essential that hazards are identified and control measures taken. A method that is usually employed for this purpose is HAZOP. In HAZOP, with the aid of guidewords, deviations from design value of different parameters of the process are identified. Then causes and consequences of all these deviations are considered. Finally the necessary safety measures are proposed in order to reduce the relevant risk or improve the process. The present dissertation work has been conducted in HG unit of IOCL, Panipat refinery, Hariyana in which Hydrogen gas (H2) is the main product. The HAZOP study is carried out of HGU excepting utility section since H2 is a hazardous gas in terms of flammability in air, toxicity and chemical instabilty, it can be handled and stored with safety, provided appropriate precautions observed. The unit is designed for operation with Straight Run Naphtha (SRN) and Coker Naphtha as feedstock. Continues operation with a mixture of SR naphtha and Coker naphtha. The operating units involved for the production of H2 in the unit are Hadrogenator reactor, Chlorine and Sulphur absorbtion, HZS stripper, H2 purification, H2 recovery and Hz storage tank. Deviation or changes in the process parameters (such as temperature, pressure, levels of chemicals etc.) of H2 operating unit may lead to a serious accidents ( violent reaction, damaged by overheating , hot spot formation etc.) and undesirable product since the product quality is sensitive; therefore qualitative and manual HAZOP study has been carried out as a dissertation work for a better performance of the process system as well as safety. The present HAZOP study report shows the possible abnormal causes and consequences of hazards in the plant. A brief result discussion is also performed based on the present HAZOP study report. And also preventive corrective measure and recommendations have been made to improve the safety performance of the process and production line as well.