Chemical Industries

sensors in the chemical industry

Temperature sensors are extremely important in the chemical industry for several reasons, mainly due to the critical role that temperature plays in chemical processes. Here are some of the main reasons:

1. process control: Many chemical reactions require specific temperature conditions to occur efficiently. The temperature needs to be controlled strictly to optimize the reaction rate, maximize yield and ensure the quality of the final product. Temperature sensors provide the data needed to maintain these ideal conditions.
2. Security: Chemical processes can be dangerous if temperatures get out of control. Exothermic reactions, for example, release heat and can lead to temperature increases that, if not monitored and controlled, can result in hazardous situations, such as explosions or chemical leaks. Temperature sensors help prevent accidents by continuously monitoring thermal conditions and allowing automatic or manual interventions when necessary.
3. energy efficiency: Keeping the temperature in a chemical process within a specific range also helps to optimize energy usage. Excessive heating or cooling not only consumes more energy but can also reduce the life of the equipment and increase operating costs. Temperature sensors help monitor and adjust energy usage, making the process more efficient.
4. equipment monitoring: Temperature can be an important indicator of the operating condition of industrial equipment. Temperature anomalies in certain parts of a machine can signal wear, imminent failure, or need for maintenance. Temperature sensors can help with predictive and preventive maintenance, avoiding unexpected and costly stops.
5. Quality control: In many chemical processes, the quality of the final product can be highly dependent on thermal conditions during production. For example, in polymer manufacturing, the temperature needs to be carefully controlled to ensure properties such as viscosity, strength and transparency. Temperature sensors ensure that ideal conditions are consistently maintained, resulting in a high quality final product.

In summary, temperature sensors are fundamental in the chemical industry to ensure efficiency, safety, quality control and process sustainability. They are key parts for operations to be conducted in an optimized and safe way.

 

most used sensors

In the chemical industry, thermocouples are chosen based on the required temperature range, operating environment, corrosion resistance, stability and cost. Some of the most common types of thermocouples used in this industry include:

1. K-type thermocouple (Nicr-Nial): Due to its wide temperature measurement range (-200 °C to +1350 °C) and good oxidation resistance at high temperatures, the K-type thermocouple is often used in ovens, boilers and other equipment operating at high temperatures. It is one of the most economical and versatile options, suitable for many chemical applications.
2. T-type thermocouple (copper-constantan): This thermocouple is known for its excellent stability and accuracy in lower temperature ranges (-270 °C to +400 °C). It is especially useful in applications that require precision at sub-zero temperatures, such as in processes involving liquefied gases or other volatile chemicals.
3. J-type thermocouple (Fe-Cuni): With an operating range from -40 °C to +750 °C, type J thermocouple is less resistant to oxidation than K type, but is still useful in reducing environments and moderately high temperatures. However, it should be avoided in oxidizing atmospheres or with temperatures above 760 °C due to the rapid oxidation of the iron.
4. Type E thermocouple (Nicr-Cuni): This thermocouple has a measuring range of -40 °C to +900 °C and offers greater sensitivity than type K, which can be advantageous to detect small temperature variations, being a common choice for laboratory applications and precise manufacturing processes.
5. S-type thermocouple (PT10RH-PT) and Type R (PT13RH-PT): These thermocouples are made of platinum and rhodium, being highly stable and accurate at high temperatures (0 °C to +1760 °C for type S, and -50 °C to +1760 °C for R type). They are very resistant to corrosion and generally used in high temperature applications, such as glass production and ceramic processes. Due to their high cost, they are less common in more generic industrial applications.

The choice of the type of thermocouple depends on the specific operating conditions and the requirements of the chemical process in question. It is crucial to consider aspects such as the chemical nature of the environment, possible interactions with other materials, temperature range and need for precision to select the most suitable thermocouple.

typical applications

In the chemical industry, thermocouples and PT100 (a type of thermoresistance or RTD) are used to measure and control temperatures in a variety of critical processes. The choice between a thermocouple and a PT100 usually depends on the required temperature range, the desired accuracy, the response to time and cost. Let’s explore some typical applications for each of these sensors:

Thermocouples are suitable for measuring a wide range of temperatures, and are especially valued in high temperature conditions and severe environments:

 

1. Ovens and Boilers: In combustion or heating processes, thermocouples are used to monitor and control the temperature inside ovens and boilers, ensuring operational efficiency and safety.
2. chemical reactors: In reactors where exothermic reactions occur, thermocouples help to monitor temperature to prevent hazardous conditions, such as overheating, which can lead to product degradation or risk situations.
3. Distillation and refining: In distillation processes, thermocouples are used to measure temperatures at different points in the distillation column, helping to optimize the process and ensure effective separation of the components.
4. Processing of plastics and polymers: Temperature is a crucial factor in plastic processing, from extrusion to injection molding. The thermocouples monitor and control temperatures to ensure the quality of the final product.

Applications for PT100

The PT100 sensors are chosen for their accuracy and stability in more moderate temperature ranges, being ideal for processes that require accurate measurements:

1. chemical process monitoring: In processes where small temperature variations can significantly change the quality of the product, the PT100s are used due to their high precision and stability.
2. Storage of sensitive chemicals: For chemicals that must be stored under controlled temperature conditions, the PT100 can help monitor and maintain optimal conditions, preventing product degradation.
3. Heating and cooling systems: In systems that require precise temperature control to maintain optimal operating conditions, the PT100s are often used for precise feedback and temperature control.
4. Research and Development: In the R&D laboratories, where precise experiments with controlled temperatures are required, the PT100s are preferred for their accuracy and reliability.

Choose between thermocouples and PT100

The choice between using thermocouples or PT100 in the chemical industry depends on several factors:

1. temperature range: thermocouples are better for very high or very low temperatures.
2. Precision: PT100 are generally more accurate in narrower and more moderate temperature ranges.
3. Cost: thermocouples are usually cheaper and simpler to replace.
4. environmental conditions: Corrosion resistance and other environmental factors can influence the choice.

In short, the choice of the ideal temperature sensor for any application in the chemical industry depends on the specifics of the process, the operating environment, the precision requirements and the temperature range involved.