Instrumentation I - Session 4 Session 04 - Agenda ActivityEst. Time 1. Agenda 2. Scantron - Homework Assignments 3. Learning Objectives 4. Introduction to Analytical Instruments/Terms 5. Analytical Devices BREAK 6. Analytical Devices, Cont. 7. Chapter 7, miscellaneous measuring device 8. Chapter 8, Control Loops LUNCH BREAK 9. Group Activity, (PFD – P&ID)

Instrumentation I - Session 4 Chapter 6 – Objectives 1. Define terms associated with analytical instruments: n pH (acid/base) and ORP n conductivity n optical measurements n chromatography n combustion (O 2 and CO) 2. Identify the most common types of analytical devices used in the process industry: n optical analyzer (turbidity analyzer/meter and/or opacity analyzer/meter) n color analyzer n conductivity meter n pH/ORP meter n gas chromatograph (GC) and GC mass spectrometer n spectrophotometer (UV/VIS and/or infrared) n total carbon analyzer 3. Describe the purpose of analytical devices used in the process industry. 4. Discuss how analytical instrumentation affects the role of the process technician and how the process technician affects the operation of the analytical instrumentation.

Instrumentation I - Session 4 Analytical Instruments

Inline Analyzer n Inliner analyzer continuously monitors the chemical and physical properties in a process stream and is capable of doing the following steps for each sample taken: n Obtaining a representative sample from the process stream n Transporting the sample to the analyzer in a way that maintains the physical and chemical integrity of the sample n Conditioning the sample so that it can be introduced into the analyzer n Analyzing the sample n Returning the sample to the process or discards the sample in another suitable manner Instrumentation I - Session 4

Quantitative and Qualitative Properties n Qualitative: Determines the composition and/or properties of a substance n Quantitative: Determines the amount or proportions of a substance Instrumentation I - Session 4

Analytical Properties n pH n ORP (Oxidation Reduction Potential) n Conductivity n Optical Measurement n Chromatography n Combustion

pH: n Is a measurement of the hydrogen ion concentration [H + ] of a solution that indicates how acidic or basic a substance is. n pH below 7 are acidic above 7 are basic and 7 are neutral pH = -log 10 (H + ) Instrumentation I - Session 4

ORP: n Is a measurement of potential created by the ratio of reducing agents to oxidizing agents present in the sample. n Where pH measurement is specific to hydrogen ion concentration ORP measurement is sensitive to free electron concentration. Instrumentation I - Session 4

pH Meter/ORP Meter

Instrumentation I - Session 4 pH Meter/ORP Meter n pH Meter: Measures the acidity and the alkalinity of a solution by measuring the hydrogen ion concentration. n pH Meter: Compares the hydrogen ions to a buffered solution.(exactly pH=7) n pH Meter: Should be calibrated by standard pH solutions at several pH levels. Table 6-1 n ORP Meter: Measures free electron potential in the sample. n ORP Meter: Are calibrated in millivolts, positive mV indicates oxidation means the loss of electrons and negative mV indicates reduction means the gain of electrons

Instrumentation I - Session 4 Conductivity: n Is a measurement of the ability of a material to conduct an electrical current n Is the inverse of resistance n Is an electrochemical property measured in microohms and in the metric unit called siemens per sqcm n When a metallic or nonmetallic substance that becomes an ionic conductor (electrolyte) dissolves in water it dissociates into cations (-) and anions (+) ions n The more ionic the solution becomes, the greater its ability to conduct an electrical charge (page 107, Figure 6-5) n The application is in measuring dissolved solids in water (blow down or treat a process fluid)

Instrumentation I - Session 4 Conductivity Meter n Uses a standard cell (1 cm 2 in size) to quantify the measurement of the ability of a process material to conduct an electrical current n Conductivity meters use standards and a reference solution to check calibration at regular intervals

Instrumentation I - Session 4 Optical Measurements n Uses reflection, refraction, or absorption properties of light (electromagnetic waves) to measure the chemical or physical properties of a sample. n Optical meters include color meters, turbidity meters, and opacity meters.

Instrumentation I - Session 4 Optical Analyzers: Color n Color measurement is the measurement of the color of sample in the visible light spectrum( micrometer) n Some off color products are impossible to sell like bottled water n Color can also indicate process problems (overheating, reaction goes too far) n Visual (analyzed by human brain) and photometers or spectral (automated) color analyzers

Instrumentation I - Session 4 Optical Analyzers: Turbidity n Measure the transmittance or absorption of light passing through a sample n Turbidity analyzer is used to determine the cloudiness of a liquid due to suspended particles. n The photometer is located across from a light source so that it detects the result of the scattering or absorption of the beam by the particulate matter in the sample

Instrumentation I - Session 4 Optical Analyzers: Opacity n Measures the amount of Particulate matters in a gas sample. Types of electromagnetic waves used for the light source within these meters include: Gamma rays X rays Ultraviolet Visible Near infrared Thermal infrared Microwave TV/radio

Instrumentation I - Session 4 Gas Chromatograph (GC) n Provides a molecular separation of one or more individual components in a sample. n This method identifies the chemical composition of the molecules within the separated sample. n GC consists of an injection port that vaporizes the sample, a column (a hollow tube filled with a special material called packing), a detector that senses the separated gases, and an output device that generates a chromatogram (peaks on a graph)

Instrumentation I - Session 4 Gas Chromatograph (GC) n The packing material is a finely ground, inert porous material n The packing is called the stationary phase n The carrier gas pushes the vaporized sample gases is called the mobile phase n All components of the sample enter the column simultaneously and move through the length of the column at different rates according to the coefficient of adsorption, MW, vapor pressure, and molecular size.

Instrumentation I - Session 4 Combustion n Is the rapid oxidation of a substance resulting in its conversion to heat, light, and gases n During complete combustion, hydrocarbon fuels such as natural gas (CH 4 ) converts to CO 2, H 2 O and heat

Instrumentation I - Session 4 Mass Spectrometer n Separates a gaseous stream into a spectrum according to mass and charge n Generally a gas sample is converted into an accelerated stream of highly charged ions. The sample is then sent through a magnetic field and then into a detector. n The more massive particles tend to go in a straight line while the less massive particles tend to move away from the center n The detector then registers these positions n GC output is on a volume percent data n Mass spectrometer provides wt. percent data and is faster than a GC

Instrumentation I - Session 4 Mass Spectrometer

Instrumentation I - Session 4 Spectrometer n Detects and quantifies chemical components in a process sample by measuring variations in transmittance(or absorption) of a spectrum of light passed through the sample. n It may use visible light (VIS), ultraviolet light (UV), or infrared (IR) light as a source and detection measurement.

Instrumentation I - Session 4 Spectrometer

Instrumentation I - Session 4 Total Carbon Analyzer n Determines the amount of Carbon (organic or inorganic) in a sample n For example in steam condensate and wastewater n The most common one converts all carbon based compounds into carbon dioxide and then determine the concentration of total carbon based on a CO 2

Instrumentation I - Session 4 Total Carbon Analyzer

Instrumentation I - Session 4 Chapter 7 - Learning Objectives 1. Define terms associated with miscellaneous measuring devices: n vibration n rotational speed. 2. Identify common types of miscellaneous measuring devices: n vibration measurement n speed measurement.

Instrumentation I - Session 4 Vibration n There are devices that do not fall in the main categories or types of instrumentation used in process facilities as described in previous chapters. n The two types that are discussed in this chapter is Vibration and speed n Vibration is an object, device, or system in the random or periodic change in velocity, acceleration, or displacement from a predetermined point. n Vibration meters measure the vibration and consist of: A pick up device, an electronic amplification circuit, and an output meter.

Instrumentation I - Session 4 Vibration n Most compressors have high vibration alarms as well as shutdowns associated with them. n Vibration can be measured with an accelerometer. n Piezoelectric is a type of accelerometer. It has a crystal that is self generating that generates a small voltage when pressed or pushed on by the operating equipment. n Piezoelectric crystal is attached to a sensing mass that is a piece of heavy metal that when the rotating equipment vibrates it changes directions, vibrating back and forth with the rotating equipment, the mass presses or pulls on the crystal that in turn responds with a voltage output. This voltage can create a signal and provide an alarm or a shutdown point.

Instrumentation I - Session 4 Vibration Meter

Instrumentation I - Session 4 Speed and Velocity

Instrumentation I - Session 4 Speed Monitor n Speed is the distance traveled per unit of time n Velocity is speed with direction n Sensors detect rotation by counting markers located on the rotating component n Speed can be monitored as in linear (ft/s) or revolutions per minute (rpm) n Over speed in turbines

Instrumentation I - Session 4 Chapter 8 – Objectives (page 1) 1. Describe process control: n variables n measuring means (primary element/transmitter) n controller (setpoint) n final control element (valve or louvers) 2. Explain the function of a control loop. 3. Describe the differences between “open” and “closed” control loops.

Instrumentation I - Session 4 Chapter 8 – Objectives (page 2) 4. Identify the components of a control loop: n sensing n measuring n Comparing n controlling n transducer (converter) 5. Explain signal transmission: n pneumatic n electronic n digital n mechanical.

Instrumentation I - Session 4 Process Control

Instrumentation I - Session 4 Most Common Control Elements

Instrumentation I - Session 4 Variables in a control loop n Process Variable: (T, P, L, F, Analytical) n Controlled Variable: (A process variable that is sensed to initiate the control signal) n Measured Variable: (a process variable that is measured) n Manipulated Variable: The final control element (e.g. control valve) is manipulated by the corrective response of the controller output so that the process variable is maintained at the appropriate setpoint value

Instrumentation I - Session 4 Feedback (Closed) Control Loop The change caused by the output of the controller is fed back into the process providing a self regulating action.

Instrumentation I - Session 4 Open Control Loop A signal path without feedback: It is a manual mode. Like when we turn off our cruise controller in our cars and manually control the speed.

Instrumentation I - Session 4 Sensing Element

Instrumentation I - Session 4 Pneumatic Signal

Instrumentation I - Session 4 Transmitter Element (converting and transmitting)

Instrumentation I - Session 4 Controlling Element (comparing, calculating and correcting)

Instrumentation I - Session 4 Transducer (Converting Element)

Instrumentation I - Session 4 Manipulating Element

Instrumentation I - Session 4 Electronic Signal

Instrumentation I - Session 4 Digital Signal

Instrumentation I - Session 4 Mechanical Link