TILI Automation

 Steam pressure is the key variable that indicates the state of balance between the supply and demand for steam. If supply exceeds demand, the steam pressure will rise conversely, and If demand exceeds supply, the steam pressure will fall. The pressure controller with main header pressure, a controlled variable manipulates the firing rate demand to control the steam pressure at the desired Setpoint. In this case, for multiple boilers and only one common header. Here the term plant master is used because more than one boiler supplies steam to a common header. The plant master generates the master firing rate demand signal that drives the individual boilers in parallel. The primary function of combustion control is to deliver fuel and air mixture to the burner at a rate that satisfies the firing rate demand for efficient combustion. Due to insufficient airflow, the fuel is wasted which makes incomplete combustion and can cause an accumulation of combustible gases. And too much airflo...

 Emerson DCS system is now a globally recognized system in the chemical as well as oil and gas industries. Nowadays Emerson remains a footprint on safety instrument systems in order to increase the plant and process safety. Most Emerson DCS systems of an oil and gas plant is having a combination of two systems one is BPCS which is called “Basic Process Control System” and SIS or ESD which is called “Safety Instrument System” or “Emergency Shut-Down System”. Here we discuss the understanding of differences between the BPCS Control system and the ESD control system and how these two systems are differentiated. Firstly, we understand what is BPCS and SIS? Basic Process Control System (BPCS) A basic Process Control System (BPCS) is a system that handles the control and monitor functions of an industrial plant process. BPCS is responsible for the proper operation of the plant, and in many instances is used as the first layer of protection. A simple example of a basic process control loo...

 Safety Instrumented System (SIS) Logics are built with safety interlocks considering multiple safe scenarios for protecting the equipment/plant. The functionality of such logics implemented either in the Basic Process Control System (BPCS) or Safety System (SIS) is very critical for the plant operations. However, there may be a need to bypass an SIS or BPCS Independent Protection Layer (IPL) function for specific reasons such as startup, testing, or maintenance. Again bypasses shall be counterchecked and removed for bringing back the equipment to operate in a safe manner. To manage this, there shall be a management system to ensure that a bypass is removed once the condition that required it has been satisfied.  Bypass Rules Written procedures shall exist for any hardware or software that permits bypass of an SIS function.  For SIS, BPCS IPL safety functions, procedures to be made available to update, edit & Bypass (as and when required), and required System Access r...

  A  gas flow meter  is used to measure the volumetric or mass flow rate of various process gases in industrial plants and machinery. The flow rate refers to the speed at which fluid is moving through closed pipes or ducts at a given time. Modern instrumentation & control engineering design needs monitoring of fluid flow rates to optimize the use of gases and improve the efficiency of processes and equipment. Therefore, a gas flow meter device must be calibrated against a reference or a master calibration system. Due to process & environmental conditions flowmeters may have some drift in flowrate readings which needs recalibration periodically for the flow range it is designed for, to achieve the desired accuracy for smooth process operation. Some organizations have an ISO audit system in place which needs recalibration at a specific time frame. Types of Gas Flow Meters Available in Market Various flowmeter technologies are available currently in the market which ...

 Most instrument manuals state there is no calibration of the temperature sensor, but the temperature sensor must be checked to determine its accuracy. This accuracy check is performed at least once per year and the accuracy check date/information is kept with the instrument. If the accuracy check date/information is not included with the instrument or the last check was over a year, the temperature sensor accuracy needs to be checked at the beginning of the sampling event. If the instrument contains multiple temperature sensors, each sensor must be checked. This procedure is not normally perform in the field. If the instrument is obtained from a rental company, the rental company should performed the calibration check and include with the instrument documentation that it was performed. Calibration Procedure: 1. Fill a container with water and adjust the water temperature to below the water body’s temperature to be measured. Use ice or warm water to adjust the temperature. 2. Place...

Conductivity is used to measure the ability of an aqueous solution to carry an electrical current. Specific conductance is the conductivity value corrected to 25 DC. Most instruments are calibrated against a single standard which is near the specific conductance of the environmental samples. The standard can be either below or above the specific conductance of the environmental samples. A second standard is used to check the linearity of the instrument in the range of measurements. When performing specific conductance measurement on groundwater or surface water and the measurement is outside the initial calibration range defined by the two standards, the instrument will need to be re-calibrated using the appropriate standards . Specific Conductance Calibration Procedure: 1. Allow the calibration standards to equilibrate to the ambient temperature. 2. Fill calibration containers with the standards so each standard will cover the probe and temperature sensor. Remove probe from its storag...

 Schematic Diagram of a Open Tank DP Level Transmitter with Zero Suppression Calibration Formulas: Min range = SG x Z + P0 Max range = (SG x Z) + (SG x H) Example: If the height of an H is 3.5 meters high and 1.5 meters Z is, in the tank, there is a liquid that has a density of 1 g / cm3 what the calibration range of the transmitter? SG = 1 Min range = SG x Z + P0 = 1 x 1,5 m + 0 = 1.5 mH 2 O Max range = (SG x Z) + (SG x H) = (1 x 1.5) + (1 x 3.5) = 1.5 + 3.5 = 5 mH2O The transmitter Range 1.5 to 5 mH2O

 The DP level transmitter installed below HP tapping point with wet leg.Schematic Diagram of a Closed tank DP Level Transmitter with wet leg elevation zero remote mount Calibration Closed tank DP Level Transmitter with wet leg elevation zero remote mount Calibration Min range = (SG x X1) – (SG x H) Max range = [(SGxX1) + (SGxX2)] – (SGxH) Example: If the height is 1 meter an X1, X2 is 3 meters and a height H is 4.5 meters, in the tank there is cairin which has a density of 1 g / cm3, what is the range of calibration on the transmitter? SG = 1 Min range = P High – P Low = (SG x X1) – (SG x H) = (1 x 1) – (1 x 4.5) = 1 -4.5 = – 3.5 mH 2 O Max range = P High – P Low = [(SGxX1) + (SGxX2)] – (SGxH) = [(1×1) + (1×2) – (1×4,5) = 4 to 4.5 = -0.5 MH 2 O The transmitter Range = -3.5 to -0.5 mH 2 O

 Calibration – The Definition Calibration is the comparsion of measurement device or an instrument(device under test, DUT) against a known with equal or better standard. The standard in a measurement is considered to be more correct of the two and one would calibrate the device under test to know far it deviates from the standard. Usual calibration usually done by commercial calibration laboratories uses a manufacturer’s calibration procedure and is performed with a reference standard multiple times more accurate typically at four times with accuracy of the DUT. So, Why Do We Need to Calibrate? Having instruments that are calibrated insures quality output products. Out of tolerance (OOT) instruments tend to give wrong readings resulting in unnecessary back jobs and process failures. Bad or low quality products would pass as good ones resulting in warranty costs, and good products as non-conformance to quality ones, resulting to unnecessary reworks. So basically, calibration is all ...

 How to do calibration checks of vibration Probe, extension cable and vibration monitor A Pyrometer is any non-contacting device that intercepts and measures thermal radiation. This measure is used to determine temperature, often of the object’s surface. The word pyrometer comes from the Greek word for fire, “πυρ”, and meter, meaning to measure. Pyrometer was originally coined to denote a device capable of measuring temperatures of objects above incandescence (i.e. objects bright to the human eye). Pyrometers are used to ‘read’ radiated heat in steel industries, ceramic manufacturing and other applications requiring high temperature from a few hundreds to thousands of degrees Celsius of temperature. Most pyrometers come in a set of a sensor and a controller. The controller may come readouts of analog or digital. I have here some pictures while in the process of calibrating pyrometers using a black body. Below is a note on the blackbody furnace and proposed standard procedure in the...

 Calibration checks of vibration Probe, extension cable and vibration monitor Calibration Procedure: 1. Physical check of vibration probe and extension cable for any damages, if it is please replaced with same one. 2. Check resistance of vibration probe and continuity of extension cable it should be 5 to 9Ω and 5 to 20 Ω 3. Use below equation and get reading for calibration of vibration probe. 4. Connect test equipment. 5. Adjust the spindle micrometer on the TK-3 test and calibration kit shown 0.51 mm (20 mils) (0.0254mm=1mils). 6. Insert the probe in to the TK-3 probe holder adjust the probe in the holder until the digital multimeter shows -3.00 ±0.10 VDC. 7. Adjust the micrometer to 0.20mm (8 mils) indication and the back it out again to the 0.25mm (10 mils) indication backless in the micrometer forced the o/p voltage and record it. 8. Increase the gap in 0.25 (10mils) increment by adjusting the micrometer record the voltage indication at each increment. 9. For each gap incremen...

 Pressure switches are commonly used in the process industry for a wide range of applications. A pressure switch is a form of sensor that closes or opens an electrical contact when a certain pressure has been obtained either through a pressure rise or a pressure drop. Pressure switches are used to monitor, control, or provide a caution or warning for a pressure related process. The repeatability, accuracy, and functionality of a pressure switch often tie directly into the safety or efficiency of a process and thus it becomes important that pressure switches are verified and calibrated to ensure their proper function in the process. Pressure Switch Calibration There are several terms that describe the function of a switch which need to be understood when testing a pressure switch: Set point: The pressure which the switch will change state.  Normal State: The state of the switch when at barometric pressure or ideal state. Depends on Pressure switch type.(typically it would be ei...

 How to calibrate the level instrument with DP type Capillary Seal sensors The use of capillary with fluid inside will the make us to have nice and careful calculation to find what is the range between 0% – 100%. Below is some examples how to find calibrated range for many possible position of the DP type Capillary Seal Level transmitter. The information given is: H = 100 Inch (Center to Center), Process SG Liquid = 1, h = 50 Inch, SG fill fluid = 1.2. What is the calibrated range? what is the required URV and LRV? for cases below: 1. The first case (atmospheric) is as follows: To find a range of 0% -100% level of process fluid with DP Type Level value corresponding instrument is as follows: 0% -> Under these conditions the fill fluid in the capillary has put pressure on the sensor even though the tank is empty. DP received by the sensor is equal to or 50 h InFillFluid InFillFluid which has SG = 1.2. To make it dimensionless InH2O then 50 InFillFluid converted = 50 x 1.2 = 60 In...