Instrumentation in petrochemical industries

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Instrumentation controls the operation of process columns Colonne distillazione.jpg
Instrumentation controls the operation of process columns

Instrumentation is used to monitor and control the process plant in the oil, gas and petrochemical industries. Instrumentation ensures that the plant operates within defined parameters to produce materials of consistent quality and within the required specifications. It also ensures that the plant is operated safely and acts to correct out of tolerance operation and to automatically shut down the plant to prevent hazardous conditions from occurring. Instrumentation comprises sensor elements, signal transmitters, controllers, indicators and alarms, actuated valves, logic circuits and operator interfaces.

Contents

An outline of key instrumentation is shown on Process Flow Diagrams (PFD) which indicate the principal equipment and the flow of fluids in the plant. Piping and Instrumentation Diagrams (P&ID) provide details of all the equipment (vessels, pumps, etc), piping and instrumentation on the plant in a symbolic and diagrammatic form.

The elements of instrumentation

Instrumentation includes sensing devices to measure process parameters such as pressure, temperature, liquid level, flow, velocity, composition, density, weight; and mechanical and electrical parameters such as vibration, position, power, current and voltage. [1]

Temperature instrumentation

Heat exchanger instrumentation Heat exchanger instramentation.jpg
Heat exchanger instrumentation

Oil, gas and petrochemical processes are undertaken at specific temperatures.

Pressure instrumentation

Diagram of the pressure instrumentation on a process vessel Vessel pressure instrumentation.jpg
Diagram of the pressure instrumentation on a process vessel

Oil, gas and petrochemical processes are undertaken at specific operating pressures.

Flow instrumentation

Diagram of a flow control instrumentation loop Analogue control loop evolution.png
Diagram of a flow control instrumentation loop

The throughput of a petrochemical plant is measured and controlled by flow instrumentation.

Compressor control Compressor control.jpg
Compressor control
Schematic of pump minimum flow protection arrangement Pump recycle.jpg
Schematic of pump minimum flow protection arrangement

Level instrumentation

Diagram of the level instrumentation on a process vessel Vessel level instrumentation.jpg
Diagram of the level instrumentation on a process vessel

The level measurement of liquids in pressure vessels and tanks in the petrochemical industry is undertaken by differential pressure level meters, radar, magnetostrictive, nucleonic, magnetic float and pneumatic bubbler instruments. [1] [9]

Analyser instrumentation

A wide range of analysis instruments are used in the oil, gas and petrochemical industries. [1] [16]

Most instruments function continuously and provide a log of data and trends. Some analyser instruments are configured to alarm (AAH) if a measurement reaches a critical level.

Other instrumentation

Pig launcher Pig launcher.jpg
Pig launcher

See also

Related Research Articles

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Pressure measurement is the measurement of an applied force by a fluid on a surface. Pressure is typically measured in units of force per unit of surface area. Many techniques have been developed for the measurement of pressure and vacuum. Instruments used to measure and display pressure mechanically are called pressure gauges,vacuum gauges or compound gauges. The widely used Bourdon gauge is a mechanical device, which both measures and indicates and is probably the best known type of gauge.

<span class="mw-page-title-main">Pump</span> Device that imparts energy to the fluids by mechanical action

A pump is a device that moves fluids, or sometimes slurries, by mechanical action, typically converted from electrical energy into hydraulic or pneumatic energy.

<span class="mw-page-title-main">Valve</span> Flow control device

A valve is a device or natural object that regulates, directs or controls the flow of a fluid by opening, closing, or partially obstructing various passageways. Valves are technically fittings, but are usually discussed as a separate category. In an open valve, fluid flows in a direction from higher pressure to lower pressure. The word is derived from the Latin valva, the moving part of a door, in turn from volvere, to turn, roll.

Instrumentation is a collective term for measuring instruments, used for indicating, measuring, and recording physical quantities. It is also a field of study about the art and science about making measurement instruments, involving the related areas of metrology, automation, and control theory. The term has its origins in the art and science of scientific instrument-making.

<span class="mw-page-title-main">Fluid power</span> Use of fluids under pressure to generate, control, and transmit power

Fluid power is the use of fluids under pressure to generate, control, and transmit power. Fluid power is conventionally subdivided into hydraulics and pneumatics. Although steam is also a fluid, steam power is usually classified separately from fluid power. Compressed-air and water-pressure systems were once used to transmit power from a central source to industrial users over extended geographic areas; fluid power systems today are usually within a single building or mobile machine.

Industrial process control (IPC) or simply process control is a system used in modern manufacturing which uses the principles of control theory and physical industrial control systems to monitor, control and optimize continuous industrial production processes using control algorithms. This ensures that the industrial machines run smoothly and safely in factories and efficiently use energy to transform raw materials into high-quality finished products with reliable consistency while reducing energy waste and economic costs, something which could not be achieved purely by human manual control.

A flow control valve regulates the flow or pressure of a fluid. Control valves normally respond to signals generated by independent devices such as flow meters or temperature gauges.

<span class="mw-page-title-main">Chemical plant</span> Industrial process plant that manufactures chemicals

A chemical plant is an industrial process plant that manufactures chemicals, usually on a large scale. The general objective of a chemical plant is to create new material wealth via the chemical or biological transformation and or separation of materials. Chemical plants use specialized equipment, units, and technology in the manufacturing process. Other kinds of plants, such as polymer, pharmaceutical, food, and some beverage production facilities, power plants, oil refineries or other refineries, natural gas processing and biochemical plants, water and wastewater treatment, and pollution control equipment use many technologies that have similarities to chemical plant technology such as fluid systems and chemical reactor systems. Some would consider an oil refinery or a pharmaceutical or polymer manufacturer to be effectively a chemical plant.

A Piping and Instrumentation Diagram (P&ID) is a detailed diagram in the process industry which shows process equipment together with the instrumentation and control devices. It is also called as mechanical flow diagram (MFD).

Level sensors detect the level of liquids and other fluids and fluidized solids, including slurries, granular materials, and powders that exhibit an upper free surface. Substances that flow become essentially horizontal in their containers because of gravity whereas most bulk solids pile at an angle of repose to a peak. The substance to be measured can be inside a container or can be in its natural form. The level measurement can be either continuous or point values. Continuous level sensors measure level within a specified range and determine the exact amount of substance in a certain place, while point-level sensors only indicate whether the substance is above or below the sensing point. Generally the latter detect levels that are excessively high or low.

<span class="mw-page-title-main">Vapor-compression refrigeration</span> Refrigeration process

Vapour-compression refrigeration or vapor-compression refrigeration system (VCRS), in which the refrigerant undergoes phase changes, is one of the many refrigeration cycles and is the most widely used method for air conditioning of buildings and automobiles. It is also used in domestic and commercial refrigerators, large-scale warehouses for chilled or frozen storage of foods and meats, refrigerated trucks and railroad cars, and a host of other commercial and industrial services. Oil refineries, petrochemical and chemical processing plants, and natural gas processing plants are among the many types of industrial plants that often utilize large vapor-compression refrigeration systems. Cascade refrigeration systems may also be implemented using two compressors.

NeSSI is a global and open initiative sponsored by the Center for Process Analysis and Control (CPAC) at the University of Washington, in Seattle.

An oil production plant is a facility which processes production fluids from oil wells in order to separate out key components and prepare them for export. Typical oil well production fluids are a mixture of oil, gas and produced water. An oil production plant is distinct from an oil depot, which does not have processing facilities.

The term separator in oilfield terminology designates a pressure vessel used for separating well fluids produced from oil and gas wells into gaseous and liquid components. A separator for petroleum production is a large vessel designed to separate production fluids into their constituent components of oil, gas and water. A separating vessel may be referred to in the following ways: Oil and gas separator, Separator, Stage separator, Trap, Knockout vessel, Flash chamber, Expansion separator or expansion vessel, Scrubber, Filter. These separating vessels are normally used on a producing lease or platform near the wellhead, manifold, or tank battery to separate fluids produced from oil and gas wells into oil and gas or liquid and gas. An oil and gas separator generally includes the following essential components and features:

  1. A vessel that includes (a) primary separation device and/or section, (b) secondary "gravity" settling (separating) section, (c) mist extractor to remove small liquid particles from the gas, (d) gas outlet, (e) liquid settling (separating) section to remove gas or vapor from oil, (f) oil outlet, and (g) water outlet.
  2. Adequate volumetric liquid capacity to handle liquid surges (slugs) from the wells and/or flowlines.
  3. Adequate vessel diameter and height or length to allow most of the liquid to separate from the gas so that the mist extractor will not be flooded.
  4. A means of controlling an oil level in the separator, which usually includes a liquid-level controller and a diaphragm motor valve on the oil outlet.
  5. A back pressure valve on the gas outlet to maintain a steady pressure in the vessel.
  6. Pressure relief devices.

A shutdown valve is an actuated valve designed to stop the flow of a hazardous fluid upon the detection of a dangerous event. This provides protection against possible harm to people, equipment or the environment. Shutdown valves form part of a safety instrumented system. The process of providing automated safety protection upon the detection of a hazardous event is called functional safety.

<span class="mw-page-title-main">Vapor–liquid separator</span> Device for separating a liquid-vapor mixture into its component phases

In chemical engineering, a vapor–liquid separator is a device used to separate a vapor–liquid mixture into its constituent phases. It can be a vertical or horizontal vessel, and can act as a 2-phase or 3-phase separator.

A high-integrity pressure protection system (HIPPS) is a type of safety instrumented system (SIS) designed to prevent over-pressurization of a plant, such as a chemical plant or oil refinery. The HIPPS will shut off the source of the high pressure before the design pressure of the system is exceeded, thus preventing loss of containment through rupture (explosion) of a line or vessel. Therefore, a HIPPS is considered as a barrier between a high-pressure and a low-pressure section of an installation.

Pipeline leak detection is used to determine if a leak has occurred in systems which contain liquids and gases. Methods of detection include hydrostatic testing, tracer-gas leak testing, infrared, laser technology, and acoustic or sonar technologies. Some technologies are used only during initial pipeline installation and commissioning, while other technologies can be used for continuous monitoring during service.

<span class="mw-page-title-main">Process plant shutdown systems</span>

A process plant shutdown system is a functional safety countermeasure crucial in any hazardous process plant such as oil and gas production plants and oil refineries. The concept also applies to non-process facilities such as nuclear plants. These systems are used to protect people, assets, and the environment when process conditions get out of the safe design envelope the equipment was designed for.

An isolation valve is a valve in a fluid handling system that stops the flow of process media to a given location, usually for maintenance or safety purposes. They can also be used to provide flow logic, and to connect external equipment to a system. A valve is classified as an isolation valve because of its intended function in a system, not because of the type of the valve itself. Therefore, many different types of valves can be classified as isolation valves.

References

  1. 1 2 3 4 5 6 7 8 Gas Processors Suppliers Association (2004). Engineering Data Book. Tulsa, Oklahoma: GPSA. pp. Section 4 Instrumentation.
  2. 1 2 3 "Recommended Practice 14C for Analysis, Design, Installation, and Testing of Basic Surface Safety Systems for Offshore Production Platforms" (PDF). American Petroleum Institute. 2007.
  3. 1 2 3 American Petroleum Institute, Recommended Practice API RP 520 Sizing, Selection, and Installation of Pressure-Relieving Devices in Refineries
  4. 1 2 3 4 5 6 7 8 9 10 P&IDS NW Hutton 1988
  5. GPSA (2004). Engineering Data Book. Tulsa, Oklahoma: GPSA. pp. Section 9 Heat Exchangers.
  6. GPSA (2004). Engineering Data Book. Tulsa, Oklahoma: GPSA. pp. Section 10 Aircooled Exchangers.
  7. GPSA (2004). Engineering Data Book. Tulsa, Oklahoma: GPSA. pp. Section 8 Fired Equipment.
  8. 1 2 3 4 5 GPSA (2004). Engineering Data Book. Tulsa, Oklahoma: GPSA. pp. Section 5 Relief Systems.
  9. 1 2 GPSA (2004). Engineering Data Book. Tulsa, Oklahoma: GPSA. pp. Section 7 Separation Equipment.
  10. 1 2 3 GPSA (2004). Engineering Data Book. Tulsa, Oklahoma: GPSA. pp. Section 13 Compressors and Expanders.
  11. GPSA (2004). Engineering Data Book. Tulsa, Oklahoma: GPSA. pp. Section 6 Storage.
  12. Alan S Morris (9 March 2001). Measurement and Instrumentation Principles. Butterworth-Heinemann. pp. 328–. ISBN   978-0-08-049648-1.
  13. Roger C. Baker (9 August 2002). An Introductory Guide to Flow Measurement. John Wiley & Sons. pp. 52–. ISBN   978-1-86058-348-3.
  14. Lipták, Béla G. (27 June 2003). Instrument Engineers' Handbook: Process measurement and analysis. Taylor & Francis, Inc. pp. 151 (Chapter 2). ISBN   978-0-8493-1083-6.
  15. 1 2 GPSA (2004). Engineering Data Book. Tulsa, Oklahoma: GPSA. pp. Section 12 Pumps and Hydraulic Turbines.
  16. 1 2 GPSA (2004). Engineering Data Book. Tulsa, Oklahoma: GPSA. pp. Section 3 Measurement.
  17. American Petroleum Institute, Recommended Practice RP 521 Guide for Pressure-Relieving and Depressuring Systems