TOC Analyzer Working Principle

Total Organic Carbon (TOC) measurement is commonly used to determine the degree of organic contamination in water.

Total Organic Carbon (TOC) is an indirect measure of organic molecules present in water and measured as carbon. Organic molecules are introduced into the water from the source water, from purification, and from distribution system materials. TOC is measured for both process control purposes and to satisfy regulatory requirements.

Analytical technologies utilized to measure TOC share the objective of completely oxidizing the organic molecules in an aliquot of sample water to carbon dioxide (CO2), measuring the resultant CO2 concentration, and expressing this response as carbon concentration. All technologies must discriminate between the inorganic carbon, which may be present in the water from sources such as dissolved CO2 and bicarbonate, and the CO2 generated from the oxidation of organic molecules in the sample.

One approach used to measure TOC involves subtracting the measured inorganic carbon (IC) from the measured total carbon (TC), which is the sum of organic carbon and inorganic carbon:

TOC = TC – IC.

TOC Technologies

The main difference between TOC technologies is how they oxidize organics.

All Total Organic Carbon (TOC) analyzers perform two functions: oxidizing organic carbon in water to CO2 and measuring the CO2 produced. What makes each TOC analyzer different is the method it uses to oxidize the organics in the water sample and the methods used to detect the resulting CO2.

The three main methods of CO2 detection used commercially are:

Non-dispersive infrared (NDIR)

Direct Conductometric (Non-selective Conductometric)

Membrane Conductometric Detection (Selective Conductometric)

NDIR TOC detectors measure CO2 in the gaseous phase, while conductometric TOC detectors measure CO2 in the liquid phase.

Non-Dispersive InfraRed (NDIR)

The non-dispersive infrared (NDIR) detector takes a preliminary reading to determine a baseline. When the sample enters the NDIR cell, the carbon dioxide molecules absorb the infrared light coming from the source, reducing the total transmittance of infrared light that reaches the detector. After all carbon dioxide has been removed from the cell, the percent transmittance returns to 100%.

Comments

PLC Program for Mixing Tank

Create a ladder diagram for controlling a batch mixing process. Implement a PLC program for mixing tank or Mixing Process using PLC Ladder Logic. PLC Program for Mixing Tank Fig : Mixing tank A tank is used to mix two liquids. The required control circuit operates as follows: A. When the START button is pressed, solenoids A and B energize. This permits the two liquids to begin ﬁlling the tank. B. When the tank is ﬁlled, the ﬂoat switch trips. This de-energizes solenoids A and B and starts the motor used to mix the liquids together. C. The motor is permitted to run for 1 minute. After 1 minute has elapsed, the motor turns off and solenoid C energizes to drain the tank. D. When the tank is empty, the ﬂoat switch de- energizes solenoid C. E. A STOP button can be used to stop the process at any point. F. If the motor becomes overloaded, the action of the entire circuit will stop. G. Once the circuit has been energized, it will continue to operate until it is manually stopped. Solution...

Ferrules and Cross Ferruling

Ferrules are identification labels provided for every wire terminations in an instrument, equipment, or electrical/instrumentation control panels. These tube-shaped sleeves can be inserted easily on each individual wire in a multi-core cable. In earlier days fixed digits/letters are used as ferrules, but now Instrumentation engineers/technicians prints out desired ferrules by using a ferrule printing machine. Typical Ferrule The numbers/ letters on the ferrules will be given as per the approved electrical hook up or loop diagrams. This helps technicians to easily identify a particular loop/wiring from a series of terminal blocks and to troubleshoot the desired terminal connection. Separate numbers on the ferrules distinguish the positive and negative polarities of wires, thus ensure the polarity protection of the instrument. Cross Ferruling As a wire is connected on its both ends, it is quite useful to use a cross reference method for wire identification. Unlike normal ferru...

What is Relay? How it Works? Types, Applications, Testing

We use relays for a wide range of applications such as home automation, cars and bikes (automobiles), industrial applications, DIY Projects, test and measurement equipment, and many more. But what is Relay? How a Relay Works? What are the Applications of Relays? Let us explore more about relays in this guide. What is a Relay? A Relay is a simple electromechanical switch. While we use normal switches to close or open a circuit manually, a Relay is also a switch that connects or disconnects two circuits. But instead of a manual operation, a relay uses an electrical signal to control an electromagnet, which in turn connects or disconnects another circuit. Relays can be of different types like electromechanical, solid state. Electromechanical relays are frequently used. Let us see the internal parts of this relay before knowing about it working. Although many different types of relay were present, their working is same. Every electromechanical relay consists of an consists of an Elect...

TILI Automation

Search This Blog