Automation in Oil and Gas Automation Improves Running of Oil and Gas Storage Terminals
Marketing storage terminals are vital to the working of any oil and gas company or refinery, as they store products, which are to be marketed to direct or indirect customers. These terminals can affect the overall business of an organization if not managed competently. Therefor, the smooth operation of the assets becomes vital for oil and gas companies...Here’s an overview of how actuation technology brought about efficiency at the Vishaka Black Oil Terminal.
The Vishaka Black Oil Terminal (BOT) at Vishakapatnam is a prestigious project by Hindustan Petroleum Corporation (HPCL). It was developed as a fast track project by the marketing projects group of HPCL within a record time of 15 months using all advanced project management techniques. To make this possible, HPCL joined hands with Mott MacDonald, a global management, engineering and development consultancy. The company provided the design, engineering, procurement, project and construction management services from the conceptual stage all the way through to handing over the entire facility to HPCL.
The facility is India’s largest fully automated black oil products terminal. It is spread over an area of 154,000 m2 with a product storage capacity of 94,000 m3 and consists of a modern automation system incorporating a Terminal Automation System (TAS). This system encompasses a tank farm management system, emergency shutdown system and a fire alarm system. The product receipt to the terminal is from Vishaka Refinery as well as jetties at the port.
The product is dispatched by road, rail and through pipelines for bunkering / tanker loading. The terminal is the first site with a provision for blending of products for customized needs of marketing, and thus makes it a full-fledged eastern hub for industries and bunkering.
Design and Planning of Oil and Gas Terminals
Owing to the hazardous nature of these tank farms, continuous monitoring of critical process parameters is a necessity. To prevent overfill situations, which can cause significant soil and ground water contamination, an accurate and reliable tank level monitoring system - Tank Farm Management System (TFMS) is required. Normally, the tanks are connected with the refinery through long pipelines with suitable isolation and the use of shutdown valves.
Also, valves for transfer of products for dispatch and homogenization are also included. However, following a recent incident at one such terminal, stringent rules have been put in place which require secondary level measurement, detailed locations of automatic isolation valves and dyke height. All of these constraints need to be taken into account during the design stage itself. Furthermore, various safety studies like risk, environment, security, escape route, hazard, operability and hazard identification has to be undertaken during the design phase. These are in addition to specific technical recommendations from qualified and experienced professionals relating to soil stability and surge analysis.
Design must include implementing safety procedures for loading and unloading of products to transport systems like rail, tanker trucks and ships. These include the use of fail-safe digital control valves and emergency shutdown systems to prevent potential ignition sources. Proper grounding permissive interlocks can be used to avoid static electricity build-up and lightning hazards.
The right Actuation Technology for Oil Terminals
As this facility was a fast track project, Auma India was brought in as the technology provider for automating flow control valves at the marketing storage facility. The company apart from being solution providers also were responsible for supplying, commissioning, troubleshooting and maintaining the electric actuators for this project. About 324 of the company’s explosionproof actuators were installed at various places for automating valves and providing 24/7 operations at the facility. These actuators are connected to the DCS through the Auma India Master station (AIMS).The distance between the control room and each field actuator is typically around 1.4 km.
The AIMS uses a Modbus TCP/IP protocol to communicate with the host system (LnTAS –provided by M/s L&T) and Modbus RTU protocol for the field actuators. It has a builtin standby support, which actively takes up the responsibilities of the AIMS when it is non-functional or unavailable to ensure minimal downtime at site.
Benefits of using AIMS in Crude Handling
Use of a standard solution for this project would have required the use of six such AIMS in redundant loop topology i.e., two AIMS for each loop. However, Auma India offered a unique feature where the same master station can provide concurrent loops without sacrificing the speed of communication or need of additional AIMS units.
For the Vishaka project, the actuators used are connected in loop topology in three concurrent loops to a single AIMS. Additionally, an option of a separate additional push button station was added to the actuators meant for the dyke area. These were all designed to satisfy the ‘MB Lal Committee Report’ safety requirements for dyke area applications.