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...

 In this post, we will see the use of ultrapure water in the semiconductor industry. Semiconductors are a very important part of our life. Daily use devices from small ones like headphones to mobiles to laptops to controllers used in automobiles; any electronic equipment cannot function without a semiconductor. Ultrapure Water in Semiconductor Industry They are the heart of any electronic device. It is important to know that there are only a handful of manufacturers in the world who deal in its making. It requires a very finest level of accuracy in making a wafer chip; even a nano mistake can make it a waste. Semiconductors require a huge amount of pure water, or you can say even ultrapure water in their manufacturing. For general knowledge, it must be known that a standard 30cm. wafer chip requires 2200 gallons of water (1 gallon is approximately equal to 4 liters). So, you can imagine the amount of water to manufacture chips in bulk daily. And the most important; is not just wate...

 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...

 In this topic, we will discuss the purpose of 100% and 30% valves. Why are both these valves required in power plants? Before starting with the discussion will see some basic aspects What is a Control Valve? A control valve is installed in a pipeline to regulate the flow rate of the fluid (Liquid, Gas, or Steam) as a response to the controller output (manipulated variable). The controller can adjust the valve opening or closing at any stage between 0% to 100%. The control valve in a pipeline does the following tasks. Stopping and starting of flow Reduce and raise the flow rate Controls the flow direction What is Non-Return Valve (NRV)? This is a one-way valve that allows the fluid to flow in one direction only. As its name implies, non-return means there is only one-directional flow. This device ensures there is no backflow of fluid in the pipeline. These valves are generally used in pump discharges and steam water pipelines. The direction symbol provided on the valve shows the di...

 Explain why the direction of flow shown in the below image goes from left to right. What would happen if we sent fluid flow through this control valve in reverse direction i.e. from right to left instead? Fluid Flow Reversed through Control Valve If we were to use this valve “backwards,” the pressure drop across the plug would tend to “slam” it closed whenever it approached the closed position. In other words, the process fluid’s differential pressure drop would make it very difficult to maintain any plug position near full-closed. This is actually an example of a mechanical feedback system. As the valve closes, the pressure drop across it (in most processes) usually rises because other pressure losses in the piping system decrease with decreased flow, leaving the valve to drop all the fluid pressure. Since plug position has an effect on pressure drop, and pressure drop exerts a mechanical force on the plug, there is a system of feedback at work here. In the proper flow direction, the feedba...

 The purpose of proof testing is to detect the failures within the transmitter that are not detected by the regular diagnostics of the transmitter. Of main concern are undetected failures that prevent the safety instrumented function from performing its intended function. Proof Testing Method The frequency of the proof tests (or the proof test interval) is to be determined in the reliability calculations for the safety instrumented functions for which the transmitter is applied. The actual proof tests must be performed more frequently or as frequently as specified in the calculation in order to maintain the required safety integrity of the safety instrumented function. The following tests need to be specifically executed when a proof test is performed. The results of the proof test need to be documented and this documentation should be part of a plant safety management system. Failures that are detected should be reported to the manufacturer. The personnel performing the proof test...