Instrumentation & Control Systems in Oil & Gas PDF

Instrumentation & Control Systems in Oil & Gas  Table of contents Chapter 1 : INTRODUCTION TO PETROLEUM INDUSTRY Chapter 2 : OIL TREATMENT PLANT ELEMENTS Chapter 3 : OIL TREATMENT PROCESS CONTROL Chapter 4 : CONTROL SYSTEM SENSING / MEASUREMENT ELEMENTS...

Instrumentation & Control Systems in Oil & Gas  Table of contents Chapter 1 : INTRODUCTION TO PETROLEUM INDUSTRY Chapter 2 : OIL TREATMENT PLANT ELEMENTS Chapter 3 : OIL TREATMENT PROCESS CONTROL Chapter 4 : CONTROL SYSTEM SENSING / MEASUREMENT ELEMENTS Chapter 5 : FINAL CONTROL ELEMENTS & PROCESS SAFETY VALVES Chapter 6 : INTRODUCTION TO AUTOMATION & CONTROL SYSTEMS Chapter 7 : PIPING & INSTRUMENTATION DRAWING , LABELS (P& ID) 1-1 What is the meaning of Petroleum oil ?  The word petroleum comes from the Latin Petra, meaning “Rock,” and oleum, meaning “oil.”  A thick, flammable, yellowish-green to black in color mixture of gaseous, liquid, and solid hydrocarbons that occurs naturally beneath the earth's surface, can be separated into fractions including natural gas, gasoline, naphtha, kerosene, fuel and lubricating oils, paraffin wax, and asphalt and is used as raw material for a wide variety of derivative products.  1-2 What is the Petrol Oil Industry?  The petroleum industry, also known as the oil industry or the oil patch, includes the global processes of :  Exploration : Includes prospecting, seismic and drilling activities that take place before the development of a field is finally decided.  Extraction & Processing : - Typically refers to all facilities for production and stabilization of oil and gas. - The reservoir and drilling community often uses upstream for the wellhead, well, completion and reservoir only, and downstream  Refining : Where oil and condensates are processed into marketable products with defined specifications such as gasoline, diesel or feedstock for the petrochemical industry. Refinery off sites such as tank storage and distribution terminals are included in this segment, or may be part of a separate distributions operations.  Transportation : Transportation of Petrol oil products is performed by means of oil Tankers or Pipelines and it depends on the amount that is being moved and its destination. The biggest problems with moving this oil are pollution and the chance of being spilled. Petroleum oil is very hard to clean up and is very toxic to living animals. So transportation must be subjected under strict and safe  1-3 Petrol oil Extraction & Processing  As mentioned in the previous point, oil Extraction &Processing are operations done after Exploration to prepare the oil to be Refined and produced in its useful form as gasoline, diesel , Gas or raw material to be used in petrochemical industries.  Here we can find a simple flowchart to describe this process as follows :  Production Wells Trunk Lines Collection Manifold Oil Treatment Plant ( INDFH – Separator – Heater Treater – Desalter – Gas Boot – Storage Tanks – Shipping Line )  2-1 Petrol oil Contents  As mentioned in the definition of petroleum oil, It is a mixture of Gases, Water and Solid Hydrocarbons ( Main core of oil ).  Oil is formed mostly from the carbon rich remains of ancient plankton after exposure to heat and pressure in Earth's crust over hundreds of millions of years. Over time, the decayed residue was covered by layers of mud and silt, sinking further down into Earth’s crust and preserved there between hot and pressured layers, gradually transforming into oil reservoirs. 2-2 How to Get Benefits From Petroleum Oil  Petroleum oil in its primary formation when produced from the production wells can’t be used in this form to get useful products.  Separation of extracted oil is performed in Treatment plants that separate its contents to get rid of associated impurities ( Like water, sand and rocks ) and keep hydrocarbons and gases to be used in Refinery plants and natural gas supply networks.  2-3 Petroleum Oil Processing Plant  AS Mentioned in the previous point, we have to perform treatment process to the extracted oil to be prepared to be refined and get the useful component.  Here we will know the process plant elements in the next PFD : 2-4 Explanation of oil treatment plant elements  Distribution Manifold : Oil from Production wells is transferred through trunk lines and collected in a manifold to be distributed inside the plant through the manifold.  INDFH ( Indirect Forced Heater ) : Oil from the manifold is received by INDFH to be heated to specific temperature to facilitate it separation.  Separator : After reaching a specific temperature by the INDFH, the oil interred the separator to separate the oil , water and gases. Water transferred to a water collection area called Disposal area. Gas transferred to FKOD then to the flare. Oil transferred to the next stage to the Heater Treater.  Heater Treater : After the separation into the separator, there is residual water and gas associated with oil in a thick layer called emulsion , so that the oil is heated again to separate the oil and water of this thick layer and some gases is produced from this process and transferred to the FKOD. Water is transferred to the disposal area. Oil is 2-4 Explanation of oil treatment plant elements  Desalter : Now the oil is pure from water and rich gases but still have a salt contents. So the Desalter treats the oil from salt by washing it by fresh water after breaking its compounds by electric transformer.  Gas Boot : After removing the salt, the oil now is pure. It passes through the gas boot to remove the associated gas with it to be transferred to storage tanks without gases.  Storage Tanks : Oil is stored in Tanks with adequate safe Specs.  Shipping Lines : It’s a system consists of shipping pumps and pipelines to transfer oil to long distances.  3-1 Variables Affecting Oil Processing  As mentioned in the previous points, the oil is extracted from the inside the earth with pressure and temperature and transferred through long distances across pipe lines with specific cross section areas, then treated in specific conditions. All these operations are affected with some parameters and variables.  These variables are as follows : a) Pressure : a-1) It is an expression of Force exerted on a surface per unit area. a-2) Its expressed as P=F/A. a-3) The most used measurement units are, PSI , Bar , Pascal. b) Level : b-1) It is an expression of the amount of liquid occupies a specific height of a Container or a vessel. b-2) The most used measurement units are meters, inches, feets. c) Temperature : c-1) It is an expression that indicates the warmth or coldness of an object or substance with reference to some standard value. c-2) The most used measurement units are Celsius (°C) , Fahrenheit (°F) , Kelvin (°K)  3-2 Control Loops  In the treatment process, we are facing the variation of the previous variables that will affect the separation process strongly.  To achieve a good and precise separation process, these variables must be controlled by means of control processes called “ Control Loop ”.  A control loop is a system made up of components ( Hardware and/or software ) control functions  needed for the measurement and adjustment of a variable that controls an individual process.  The old control loops was depending on pneumatic control systems that uses air or hydraulic power to operate and control the final control elements ( control valves and shutdown valves ).  The modern control loops are depending on software components like PLC & SCADA systems that collects data through smart field devices like electronic transmitters and switches then processing these data and gives electronic signals to the final control elements.  Every variable affects the process of treatment is controlled by a control loop may be individual or accompanied with another variable to make a control loop.  Control loops are named according to the controlled variable as, Pressure control loop , temperature control loop or level control loop.  3-3 Control Loop Types  The types of control loops are as follows : a) Open loop control system : Open loop system includes a controller and controlled device but no means for reporting the value of the process back to the controller. The controlled device acts directly on the process input. It can be represented as On/Off control system. b) Closed loop control system : provides feedback, that is a means for measuring and correcting the value of the process output. The main advantage of closed loop system is its ability more accurate control of a process, which justifies its use despite its greater tool..  3-4 Control Loop Elements  The most used control system is the closed loop control system because it is more accurate in controlling a process and keeps the variables in its desired values.  The main elements of a control loop are : a) Sensing element : It is the device that measures the variable and provides the feedback to the controller such as transmitters or switches. b) Controller: It is the part that collects data from the sensing element and gives a signal to the final control element. It is a software part in the modern control system. c) Final control Element: It is the device that gives the action to keep the process in the desired condition. Such as control valves and shutdown valves.  3-5 Separator Control Loops  The separator is a three phase separation device that separate water, oil and gas.  To achieve a good separation process we must control at least 2EA variables Pressure and Level inside the separator.  Here we can represent the separator control loops as follows :  3-5 Separator Control Loops  In the separator shown above, we can see 3EA control loops as follows : 1) Fluids level control loops consist of level transmitter , controller and 2EA level control valves LCV #1 for water level and LCV #2 for oil level. 2) Gas Pressure control loop consist of Pressure transmitter , controller and 1EA Pressure control valve PCV. 3) In the controller block we can find 3EA parameters as follows : SP : set point of required variable value to be around it. Determined by operator PV : the existing variable value. OP : the output of the controller to the control valve. 4) For example, we want to keep the pressure inside the separator at 100 psi so : a) The pressure transmitter will sense the pressure and send the value to the controller. b) If the pressure is greater than 100 psi, the controller will send a signal to the control valve to open gradually till the pressure reaches 100 psi and then close gradually again. c) If the pressure is less than 100 psi, the controller will keep the valve closed. 5) For the level control loop we want to keep the water or oil level around 50% of the - Introduction to Sensing / Measurement ( Definition & Types ) - Transmitters - Level Devices - Pressure Devices - Flow Devices - Temperature Devices  4-1 Introduction to sensing / Measurement  The term Sense is the detection of a physical presence & attribute for an object or event and the conversion of that to some sort of data into a signal that can be read by an observer or an instrument.  The term Measurement is the Quantification of Attributes of an object or event, which can be used to compare with other objects or events.  Measurement Device is a combination of a sensing element and measurement tool to show the amount, Quantity or Degree of an object or event.  4-2 Measured Variables and Mesuring devices In oil & Gas Industry, there are five main variables to be measured to control the production process as follows : a) Level b) pressure c) Flow d ) Temperature  Measurement Devices In Oil & Gas are categorized into two main Categories : a) Transmitters :  A device that convert the amount of a physical QTY into a signal to be used in the control loop to control a process.  The Transmitter is a part of a Control loop. b) Switches : A switch is an electrical component that senses a Pre-determined physical QTY and then disconnect or connect the conducting path in an electrical circuit or interrupting the electrical current. The switch is a part of the ESD system.  Note Transmitters are identified by the Process they Measure, NOT their Principle of Operation.. ( Level , Pressure , Flow , etc ………. ) Transmitter or Switch  4-3 Types of Measuring Devices per variable  4-3-1 Level Transmitters  Definition : A device that provides continuous level measurement over the range of the system rather than at a single point and produce an output signal that directly co-relates to the level within a vessel 4-20mA to be processed in the control system.  TYPES OF LEVEL TRANSMITTERS 1- Displacer Level transmitter :  Operates by detecting changes in buoyancy force caused by liquid levelchange.  These forces act upon the spring supported displacer causing vertical motion of the core within a linear variable differential transformer. 2- Differential Pressure Level transmitter :  A device that uses pressure readings and specific gravity to output level values by the use of the following Equation : P = ρ*g*h Where : ρ = density of the liquid / g = acceleration due to gravity / h = height of the column of liquid  This Method is commonly used in Tank Level Measurement. 3- Radar Level transmitter :  A device that works based on the time of flight (TOF) measuring principle or time domain Reflectometry (TDR). To start with, we can measure the distance from the reference point to the surface of a liquid. Then the meter sends a high-frequency signal from an antenna or along a probe.  This Method is commonly used in Tank Level Measurement. 4- Guided Wave Radar Level transmitter :  Guided wave radar is based on microwave technology. Microwaves are only affected by materials that reflect energy which means that temperature variations, dust, pressure, and viscosity do not affect accuracy. To start with, we can measure the distance from the reference point to the surface of a liquid. Then the meter sends a high-frequency signal from an antenna or along a probe.  4-3-2 Pressure Transmitters  Definition :  Pressure : Pressure is an expression of the force required to stop a fluid from expanding, and is usually stated in terms of force per unit area P=F/A.  Pressure Transmitter : is a device for pressure measurement of gases or liquids based on the above principle.  4-3-3 Flow Transmitters  Definition :  Flow Measurement : is the quantification of bulk fluid movement.  Flow can be measured in a variety of ways that will be illustrated in the next slides. DP Flow transmitter Turbine flowmeter  TYPES OF FLOW TRANSMITTERS 1- Differential pressure Flow Transmitters:  Differential pressure flow meters use laminar plates, an orifice, nozzle, or Venturi tube to create an artificial constriction then measure the pressure loss of fluids as they pass that constriction.  According to Bernoulli's principle, the pressure drop across the constriction is proportional to the square of the flow rate.  The higher the pressure drop, the higher the flow rate. These rugged, accurate meters are ideal for a wide range of clean liquids and gases. 2- Turbine Flow Transmitters:  Turbine Flow Meter is a volumetric measuring turbine type. The flowing fluid engages the rotor causing it to rotate at an angular velocity proportional to the fluid flow rate.According to Bernoulli's principle, the pressure drop across the constriction is proportional to the square of the flow rate.  The angular velocity of the rotor results in the generation of an electrical signal (AC sine wave type) in the pickup. The summation of the pulsing electrical signal is related directly to total flow.  The frequency of the signal relates directly to flow rate. The vaned rotor is the only moving part of the flow meter. 3- Ultrasonic Flow Transmitters:  The ultrasonic flow meter is a volumetric flow measurement device with a wide range of applications for liquids and gases.  Ultrasonic flow meters use sound waves at a frequency beyond the range of hearing (typically 0.5, 1, or 4 MHz).  This ultrasound signal is sent into a stream of flowing liquid by using wetted (insertion) transducers that make direct contact with the liquid or external (clamp-on) transducers that send the ultrasound through the pipe wall. Fixed Ultrasonic flow meter portable Ultrasonic flow meter 4- Electromagnetic Flow Transmitters:  A magnetic flow meter is a transducer that measures fluid flow by the voltage induced across the liquid by its flow through a magnetic field.  A magnetic field is applied to the metering tube, which results in a potential difference proportional to the flow velocity perpendicular to the flux lines. The physical principle at work is electromagnetic induction.  The magnetic flow meter requires a conducting fluid, for example, water that contains ions, and an electrical insulating pipe surface, for example, a rubber-lined steel tube.  4-3-3 Pressure Transmitters  Definition :  A temperature transmitter is an electrical instrument that interfaces a temperature sensor for example a thermocouple, RTD, or thermistor sensor to a measurement or control device like a PLC, DCS, PC, loop controller, data logger, display, recorder.  Typically, temperature transmitters isolate, amplify, filter noise, linearize, and convert the input signal from the sensor then send or transmit a standardized output signal to the control device. Common electrical output signals used in manufacturing plants are 4-20mA or 0-10V DC ranges. For example, 4mA could represent 0°C and 20mA means 100°C.  TYPES OF TEMPERATURE TRANSMITTERS 1- RTD Temperature Transmitters:  An RTD (Resistance Temperature Detector or Resistance Temperature Device) is one of the most prevalent temperature sensors used in industry today. Also commonly referred to as PT100, its resulting popularity is due to its accuracy and repsonse at temperatures between -300 to + 600 ° F.  The RTD sensor comprises of a resistor that changes value with temperature. The most common RTD by far is the PT100 385. This element measures 100 Ohms @ 0 degrees C (32 °F) and 138.5 Ohms @ 100 °C (212.0 °F). 2- Thermocouple Temperature Transmitters:  Thermocouple temperature transmitters convert the small millivolt (mV) output of a thermocouple to a current signal (typically 4-20 mADC) that is immune to noise and voltage drops over long distances.  They are used with thermocouple temperature probes, bimetallic devices that are suitable for various temperature sensing applications.  It consists of two wire legs made from different metals. The wire’s legs are welded together at one end, creating a junction. This junction is where the temperature is measured. When the junction experiences a change in temperature, a voltage is created. The voltage can then be interpreted by calculating the temperature.  Thermocouples are typically selected because of their low cost, high-temperature limits, wide temperature ranges, and durable nature. 3- Thermistor Temperature Transmitters:  Thermistor temperature transmitters is a thermally sensitive resistor that exhibits a continuous, small, incremental change in resistance correlated to variations in temperature  It provides higher resistance at low temperatures ( NTC ) or. higher resistance at High temperatures ( PTC ), according to its R-T table. - Control Valves - Shutdown Valves - Relief Valves  5-1 Final Control Element  The term Final control Element is defined as a mechanical device that physically changes a process in response to a change in control system set point.  Final control elements are relevant to actuators include valves, dampers, gates, and burners.  Final control elements are an essential part of process control systems, allowing an operator to achieve a desired process variable output by manipulating a process variable set point.  Our concern here for the final control element is the CONTROL VALVE.  5-1 Final Control Element  What is a Control Valve A control valve is an inline device in a flow stream that receives commands from a controller and manipulates the flow of a gas or fluid.  5-1 Final Control Element  Control Valve Parts :  The control valve Has two main parts: a) Actuator: It is the mechanism for opening and closing a valve. b) Body: It is the part that the fluid passes through it with certain pressure drop. Actuator Body  5-1 Final Control Element  Control valve characteristic  All control valves have an inherent flow characteristic that defines the relationship between ‘valve opening’ and flow rate under constant pressure conditions.  Note that ‘valve opening’ in this context refers to the relative position of the valve plug to its closed position against the valve seat. It does not refer to the orifice pass area. The orifice pass area is sometimes called the ‘valve throat’ and is the narrowest point between the valve plug and seat through which the fluid passes at any time.  For any valve, however it is characterized, the relationship between flow rate and orifice pass area is always directly proportional.  5-1 Final Control Element  Here under we can see the control valves characteristic as follows : a) Linear: flow capacity increases linearly with valve travel. b) Equal percentage:  Flow capacity increases exponentially with valve trim travel.  Equal increments of valve travel produce equal percentage changes in the existing Cv. c) Quick opening:  Provides large changes in flow for very small changes in lift. It usually has too high a valve gain for use in modulating control. So it is limited to on-off service, such as sequential operation in either batch or semi-continuous processes.  5-1 Final Control Element  Control valve Types  Control valves are categories by valve body.  The main types of control valves are : a) Sliding Stem : a-1) Globe valve : A type of valve used for regulating flow in a pipeline, consisting of a movable disk-type element and a stationary ring seat in a generally spherical body. a-2) Angle seat piston valve : Is a pneumatically-controlled valve with a piston actuator providing linear actuation to lift a seal off its seat. The seat is set at an angle to provide the maximum possible flow when unseated. Angle seat piston valves are particularly suited to applications where high temperatures and large flow rates are required, such as steam or water. When used in reverse some models of angle seat piston valve will eliminate water hammer when operated.  5-1 Final Control Element b) Rotary: b-1) Ball valve : is a form of quarter-turn valve which uses a hollow, perforated and pivoting ball to control flow through it. It is open when the ball's hole is in line with the flow and closed when it is pivoted 90-degrees by the valve handle. The handle lies flat in alignment with the flow when open, and is perpendicular to it when closed, making for easy visual confirmation of the valve's status. b-2) Butterfly valve : a disk-shaped valve turning on an axis along its diameter, serving ESP. as a damper in a pipe or as a choke or throttle in a carburetor  5-1 Final Control Element  Control valve Accessories  To operate a control valve, some accessories must be used as follows: a) Positioner: It is a device used to put the valve in the correct position by increasing or decreasing the air load pressure on the actuator. Valve positioners are used for controlling valve where accurate and rapid control is required without error or hysteresis. b) Pressure Regulator : This device is used to adjust the air supply pressure to the valve actuator  5-1 Final Control Element c) I/P Transducer: The I/P transducer converts an electronic signal, typically from a control system, to a pneumatic signal used to control a valve. This signals from the control system are typically analog signals in the range of 4 to 20 milliamps. The milliamps converted then to a pneumatic signal range of 3-15 psi or 6-30 psi. d) Limit switch: It’s a device that produce indication of valve opening and closing status.  5-1 Final Control Element  Control valve Operation  Taking in consideration air operated control valve, There are two types of control valve operation as follows : 1- Air to open valves :  The valve here is normally closed.  That the controller of a control loop sends a signal to the positioner or to the I/P to open the valve by allowing air move the valve diaphragm to pull the actuator stem to the upward direction to open the valve. 2- Air to Close valves :  The valve here is normally open.  That the controller of a control loop sends a signal to the positioner or to the I/P to close the valve by allowing air to move the valve diaphragm to push the actuator stem to the downward direction to close the valve.  5-2 Process Safety Valves  The term Process Safety Valves is defined as valves that used to limit the inlet flow and/or the process pressure to prevent process upset, instrument or equipment failure, or fire.  These valves are used to protect process against over flow or over pressure.  Here we will introduce two types of valves according to process protection as follows : a) Against over flow: Shutdown valves. b) Against over pressure : Pressure Relief valves  5-2 Process Safety Valves  What is a Shutdown Valve  A shut down valve (also referred to as SDV or Emergency Shutdown Valve, ESV, ESD, or ESDV) is an actuated valve designed to stop the flow of a hazardous fluid upon the detection of abnormal operating conditions. This provides protection against possible harm to people, equipment or the environment.  It is also known as a Shutoff pressure valve when used in a gas protection loop.  Shutdown valves are primarily associated with the petroleum industry although other industries may also require this type of protection system  5-2 Process Safety Valves  Shutdown Valve Parts  The Shutdown valve Has two main parts: a) Actuator: It is the mechanism for opening and closing a valve. b) Body : It is the part that the fluid passes through it with certain pressure drop.  5-2 Process Safety Valves  Shutdown Valve Types  Shutdown valves Types with reference to actuator power are classified as : a) Pneumatic Cylinder : Is a mechanical device which use the power of compressed gas or air to produce a force in a reciprocating linear motion. b) Hydraulic Cylinder : Is a mechanical device which use the power of compressed hydraulic fluid. It has many applications, notably in construction equipment (engineering vehicles), manufacturing machinery.  5-2 Process Safety Valves  Pneumatic Actuator  The most used Shutdown valves in petroleum industries are the Pneumatic actuators type.  Pneumatic actuators types with reference to the actuator variation manner as follows : a) Single-acting cylinder / Spring return: In which the working fluid ( Air ) acts on one side of the piston only to move the cylinder in one direction by force and then return to the other direction by releasing the fluid power applied to a spring, so the spring pushes the cylinder back to its original position.  5-2 Process Safety Valves  Pneumatic Actuator a) Double-acting cylinder : Is a cylinder in which the working fluid acts alternately on both sides of the piston. The air enters from a side to move the piston to a specific direction and enters from the other side to return back the piston to its original position.  5-2 Process Safety Valves  Shutdown Valve Accessories  The shutdown valve is connected to the process and to operate it, some equipment are associated to receive the control system signal and deliver it to the valve also equipment to regulate the operating fluid pressure and quantity to the actuator.  The main accessories are : 1) Pressure regulator : This device is used to adjust the air supply pressure to the valve actuator.  5-2 Process Safety Valves  Shutdown Valve Accessories 2) Solenoide valve : is an electromechanical device in which the solenoid uses an electric current to generate a magnetic field and thereby operate a mechanism which regulates the opening of fluid flow in a valve.  5-2 Process Safety Valves  Shutdown Valve Accessories 3) Limit Switch: It’s a device that produce indication of valve opening and closing status. 4) Quick Exhaust Valve: Piston valves or diaphragm valves, designed to quickly exhaust pneumatic cylinders. These types of valves are installed in the inlet of a spring return and they can also be installed in the double acting pneumatic cylinder.  5-2 Process Safety Valves  Shutdown Valve Operation  Shutdown valves installed in the process line in the inlet or the outlet of a vessel or a pipe line of production wells to protect the process from a dangerous event.  The shutdown valve is a failsafe open in case of blow down operation in Gas lines.  The shutdown valve is a failsafe close in case of shutdown operation in fluid lines.  It receives an electric signal from the control system to the solenoid valve to supply air to the actuator to move the valve body either to open or close according to if it is used as shutdown or blow down valve.  An indication and confirmation of opening and closing states is produced by Limit Switch installed over the actuator and linked with the rotating rod.  5-2 Process Safety Valves  What is a Relief Valve  A Pressure Relief valve: is a type of safety valve used to control or limit the pressure or vacuum in a system; pressure might otherwise build up and create a process upset, instrument or equipment failure, or fire.  The pressure is relieved by allowing the pressurized fluid to flow from an auxiliary passage out of the system.  It is considered as the last defense line to protect the system.  5-2 Process Safety Valves  Relief Valve Types  Relief valves are classified as: 1) Safety relief valve (SRV): A relief valve that can be used for gas or liquid service. However, the set pressure will usually only be accurate for one type of fluid at a time.  5-2 Process Safety Valves  Relief Valve Types 2) Pressure Relief Valve (PRV): Also known as pressure safety valve (PSV), it is the same like SRV but the difference is that PSVs have a manual lever to activate the valve in case of emergency..  5-2 Process Safety Valves  Relief Valve Types 3) Pilot Operated Relief Valve (POSRV, PORV, POPRV): A device that relieves by remote command from a pilot valve which is connected to the upstream system pressure.  5-2 Process Safety Valves  Relief Valve Types 4) Pressure Vacumm Relief Valve (PVRV ):  Valves that used to protect the system from both the over pressure and vacuum.  It is commonly used in tanks and pumping applications.  It consists of two disc plates with certain weights to act against pressure or vacuum.  5-2 Process Safety Valves  Relief Valve Operation 1) For safety Relief and Pressure Relief valves:  The working principle of a conventional spring-loaded safety relief valve is based on the balance of force.  The spring load is preset to equal the force the inlet fluid exerts on the closed disk when the system pressure is at the set pressure of the valve.  The disk remains seated on the nozzle in the closed position when the inlet pressure is below the set pressure.  The valve opens when the inlet pressure exceeds set pressure, overcoming the spring force.  The valve recloses when the inlet pressure is reduced to a level below the set ­pressure.  5-2 Process Safety Valves  Relief Valve Operation 2) For Pilot operator Relief valves:  A pilot-operated safety relief valve is a pressure relief valve in which the major relieving device is combined with and controlled by a self-actuated auxiliary pressure relief.  A pilot is used to sense process pressure and to pressurize or vent the dome pressure chamber, which controls the valve opening or closing.  At below-set level, the pressure on opposite sides of the moving member is equal.  When the set pressure is reached, the pilot opens and depressurizes the cavity on the top side so the unbalanced member moves upward, causing the main valve to relieve.  When the process pressure decreases to a predetermined pressure, the pilot closes, the cavity above the piston is depressurized and the main valve closes.  5-2 Process Safety Valves  Relief Valve Operation 3) For Pressure Vacumm Relief valves:  It depends on the principle of weight against pressure or vacuum through Disc plate.  In some types, a combined system of spring and plates is used, but commonly Disc plates are used.  When a set pressure is exceeded, the pressure pushes the pressure plate up to allow pressure release and when pressure returns back normal, the plate returns to its original position again.  When a set Vacuum pressure is exceeded, the vacuum pulls the pressure plate up to allow entering the atmosphere air inside a tank and when pressure returns back normal, the plate returns to its original position again. - Automation Definition. - Components of Automation system. - SCADA Systems. - DCS Systems. - Programmable Logic Controller (PLC) - Industrial Communications systems. - Human Machine Interface HMI.  Automation & Control for Process  The term Automation is defined as the Technique of making an apparatus, a process, or a system operate Automatically by mechanical or electronic devices that take the place of human labor.  The aim of automation is to enable plants and machinery to automatically perform work processes efficiently and at a low error rate.  Various levels of automation could be achieved, depending on the complexity of the systems involved. The higher the degree of automation, the less intervention needs to be performed by humans to control the process Benefits of Automation 1- Relieve people from having to perform dangerous and physically exhausting activities. 2- Machines are able to perform tiring routine jobs. 3- Machines are able to operate continuously and with a high level of performance. 4- Automation improves the quality of products and reduces personnel costs.  Components of Automation system  The Automation system is primarily consists of subsystem to complete the full automated system for a process as follows : 1- The Power distribution system  Feeds power to components, such as motors, drives, and controllers. 2- Motor control and drives  Motors have special needs in machine control.  For every motor, a proper form of electrical control is required, from simple on/off to more complex variable speed applications.  Motor control devices include manual motor starters, motor contactors and starters with overloads, drives, and soft starters.  A motor circuit must include both overcurrent (short circuit) and overload protection 3- Safety system  A risk assessment drives the safety system design as needed to remove motion-causing energy, including electrical and fluid power, to safely stop the equipment for protection of both personnel and machines.  Safety relays or safety-rated controllers must be used to monitor safety switches, safety limit switches, light curtains, and safety mats and edges.  The process safety system includes both operational and F&G protections.  The safety system is described through Cause & Effect Matrix ( C&E ) that determines a Single or several Actions with the presence of a pre-determined conditions extacted from the Risk Assessment 4- Industrial Control System for a process ( ICS )  ICS is a collective term used to describe different types of control systems and associated instrumentation, which include the devices, systems, networks, and controls used to operate and/or automate industrial processes.  Depending on the industry, each ICS functions differently and are built to electronically manage tasks efficiently.  There are several types of ICSs, the most common of which are :  SCADA : Supervisory Control and Data Acquisition.  DCS : Distributed Control Systems.  PLC : Programmable Logic Controller.  The above Types will be Illustrated in the next Slides.  SCADA SYSTEM  SCADA is not a system that can provide full control. Instead its capabilities are focused on providing control at the supervisory level.  SCADA systems are composed of devices (generally Programmable Logic Controllers (PLC) or other commercial hardware modules) that are distributed in various locations.  SCADA systems can acquire and transmit data, and are integrated with a Human Machine Interface (HMI) that provides centralized monitoring and control for numerous process inputs and outputs.  The primary purpose of using SCADA is for long distance monitoring and control of field sites through a centralized control system.  Field devices control local operations such as opening or closing of valves and breakers, collecting data from the sensor systems, and monitoring the local environment for alarm conditions.  SCADA systems are commonly used in industries involving pipeline monitoring and control, water treatment centers and distribution, and electrical power transmission and distribution. SCADA SYSTEM  DCS SYSTEM  DCS is a system that is used to control production systems that are found in one location.  In a DCS, a setpoint is sent to the controller that is capable of instructing valves, or even an actuator, to operate in such a way that the desired setpoint is maintained. Data from the field can either be stored for future reference, used for simple process control, or even used for advanced control strategies with data from another part of the plant.  Each DCS uses a centralized supervisory control loop to manage multiple local controllers or devices that are part of the overall production process.  This gives industries the ability to quickly access production and operation data. And by using multiple devices within the production process, a DCS is able to reduce the impact of a single fault on the overall system.  A DCS is also commonly used in industries such as manufacturing, electric power generation, chemical manufacturing, oil refineries, and water and wastewater treatment. DCS SYSTEM  PLC SYSTEM  PLC is a type of hardware that is used in both DCS and SCADA systems as a control component of an overall system.  It also provides local management of processes being run through feedback control devices such as sensors and actuators.  In SCADA, a PLC provides the same functionality as Remote Terminal Units (RTU).  In DCS, PLCs are used as local controllers within a supervisory control scheme.  PLCs are also implemented as primary components in smaller control system configurations. 5- Communication systems  Communication is an important part of machine control now and for the future is extensive communication capability.  It is a good practice to have multiple Ethernet and serial ports available to integrate to a variety of equipment, computers, HMIs, and business and enterprise systems.  Multiple high-speed Ethernet ports ensure responsive HMI communication, as well as peer-to-peer and business system networking.  Support of industrial Ethernet protocols, including Ethernet/IP and Modbus TCP/IP, is also important for scanner/client and adapter/server connections.  These Ethernet connections enable outgoing email, webserver, and remote access communication functions-all important options for process control.  Process control often benefits from the availability of legacy communication methods, such as serial RS-232 and RS-485. Modern controllers often also include USB and MicroSD communication and storage options.  A big part of machine control communication is cyber security. Consider a layered defense where protection includes remote functions that are only enabled as part of the hardware configuration.  For further protection, all tags should be protected from remote access unless the tag is individually enabled for that purpose. 5- Communication systems 5- Human-machine interface ( HMI )  The HMI shows vital information about machine conditions using graphical and textual views.  HMIs can be in the form of Touch panels, Text panels, Message displays, or Industrial monitors.  Support of industrial Ethernet protocols, including Ethernet/IP and Modbus TCP/IP, is also important for scanner/client and adapter/server connections.  They are used for Monitoring, Control, Status reporting, and Many other functions.  HMIs can also act as data hubs by connecting to multiple networked devices.  In some machine control applications, multiple protocols may be used, and often HMIs can be used for protocol conversion.  This functionality can be used to exchange data, such as status and set points, among different controllers and other smart devices.  Some HMIs can also send data to the cloud or enable remote access functionality through the Internet, given proper user name and password authentication. 5- Human-machine interface ( HMI ) Finally,  Machine automation systems consist of multiple subsystems and components to provide the required power distribution, safety, and real-time control.  Each of these subsystems and components must work together, and many are often networked to each other via either hardwiring, or increasingly via digital communication links.  Careful design, selection, integration, and testing will ensure the automation system performs as required, both initially and throughout the life cycle of the machine. - Definition - P&ID Components - P&ID Legend - Actual P&ID Case study  What is P&ID  P&ID (piping and instrumentation diagram)  It is a detailed diagram in the process industry which shows the piping and process equipment together with the instrumentation and control devices.  A diagram which shows the interconnection of process equipment and the instrumentation used to control the process. In the process industry, a standard set of symbols is used to prepare drawings of processes  Moreover, It is The primary schematic drawing used for laying out a process control installation.  Components of the P&ID 1- Mechanical equipment, including:  Pressure vessels, columns, tanks, pumps, compressors, heat exchangers, furnaces, wellheads, fans, cooling towers, turbo-expanders, pig traps.  Bursting discs, restriction orifices, strainers and filters, steam traps, moisture traps, sight-glasses, silencers, flares and vents, flame arrestors, vortex breakers.  Components of the P&ID 2- Process piping, sizes and identification, including:  Pipe classes and piping line numbers.  Flow directions.  Interconnections references.  Permanent start-up, flush and bypass lines.  Pipelines and flow lines.  Components of the P&ID 3- Process control instrumentation (names, numbers, unique tag identifiers), including:  Valves and their types and identifications (e.g. isolation, shutoff, relief and safety valves, valve interlocks).  Control inputs and outputs (sensors and final elements, interlocks).  Miscellaneous - vents, drains, flanges, special fittings, sampling lines, reducers and swages.  Pipelines and flow lines.  P&ID Symbols Legend  Legend :  It is the first page/s that will be faced in the P&ID drawing.  These pages include : - Abbreviations. - Fluid & Line identifications. - Equipment symbols. - Equipment Labeling. - Valves symbols & Actuator types. - Instrument Tagging and Identifiers.  P&ID Case study  An Actual P&ID Drawing will be studied and Explained in this section.