Looking for the Best Temperature Measurement Solutions for Your Cement Plant? Eureka Has Got You Covered!

Temperature is a widely measured physical parameter in all process industries. In Cement Industries, Temperature Measurement and Control is critical to achieving high-quality Cement and maximum efficiency.

Various types of temperature sensing instruments are used at various stages of Cement processing. Some of them are -Thermocouples, Resistance Temperature Detectors (RTDs), Infrared Non-Contact Thermometers & Dial Gauges.

Before going into the details of Temperature sensors and other products, the following is a brief description of the cement manufacturing process.

Cement - Manufacturing Process

Step 1 – Raw Material Quarrying:

The cement manufacturing process starts with limestone and clay, the basic raw material used to make cement containing Lime (Ca CO3), Silica (SiO2), Alumina (Al2O3) and Ferrous Oxide (Fe2O3). The raw materials are transported by road, rail or conveyer to the Quarry to the factory.

Step 2 – Raw Material Preparation:

The limestone is combined with clay, ground in a crusher to fine particles and fed into the additive silos. Sand, iron and bottom ash are then combined with the limestone and clay in a carefully controlled mixture which is ground into a fine powder in a roller mill.

Step 3 – Pre Heating:

Next, the fine powder is heated as it passes through the Pre-Heater Tower. The raw meal is drawn from the homogenization silos and fed to the typical five-stage preheater. A preheater is a form of heat-exchanger where hot gases from the kiln are drawn up through a parallel-cum- counter-current heat exchanger, coming in contact with the hot gas raw meal is partially calcined.

Step 4 – Clinkering:  

The dried and heated raw material is fed into a large rotating kiln. In the kiln, the powder is heated to 1500 degrees Celsius. This creates a new product, called clinker, which resembles pellets about the size of 3 cm marbles. During the process of heating, Silica, alumina and lime are converted into calcium aluminates.

Step 5 - Cooling the Clinkers:

The hot clinkers cannot be used directly for further processing. The clinkers are stored and cooled to a temperature of 50 to 55 degrees centigrade. 

Step 6 - Clinker Crushing & Cement finishing: The clinker is cooled, combined with small amounts of gypsum and limestone and finely ground in a finishing mill. The mill is a large revolving cylinder containing heavy steel balls that are driven by a motor. The finished cement is ground so fine that it can pass through a sieve.

Step 7 - Storage and Packing:

The cement is then stored in large silos until weighing and packing. Packed cement is then supplied to the market.

Temperature Sensors: Thermocouples

The process conditions are extremely severe. High Temperature, Hight Velocity particles hitting the Thermocouple surface, corrosive gas, abrasive environment and vibration exist in the Cement plant.

Various Types of Thermocouples, such as Type K, N, J, R & S are mainly used in Cement processing. All Thermocouples are designed and manufactured with special Protection sheaths and Thermowells. The type of Thermocouple is chosen based on the various process conditions such as Temperature, Chemical Corrosion, and Erosion due to solid particles hitting. 

Preheater cyclone Thermocouples:

These Thermocouples are installed in Cyclones. Preheater cyclone Thermocouples are designed by Eureka Engineering to have an extended life in these severe conditions. Special Grade, Thick wall Stainless steel protection sheath with Ceramic Coating protect the Thermocouple from failure due to aberration.

Kiln Inlet:

It is very important and crucial to continuously monitor the Kiln Inlet Temperature. 

These Thermocouples are engineered to withstand very High Temperatures and harsh Chemical Corrosive Conditions. 

Here, Thermocouples with Double Protection Sheaths, made of very Thick wall Ni-Cr Alloy are used. Generally Type K or N, mineral insulated sensors are used to safely measure up to 1200 Deg C. Some plant conditions require monitoring much higher temperature and therefore, Type R, S – Platinum Thermocouples are used. 

Here, the protection sheaths are Re-Crystallized Alumina ceramic Sheaths. These Type K Thermocouples are highly accurate, and come with Class 1 Accuracy and low drift, and with mineral insulated sensors, and are suitable up to 1200 Deg C.

Tertiary Air Duct & Calciner:

High-velocity abrasive clinker dust at high-Temperature is present in the hot gases. 

Eureka Engineering made an innovative new design to safeguard the long life of Thermocouples. 

Thick wall heavy duty Stainless Steel Outer sheath, High-temperature Ceramic coating for extra protection & inner space compacted with refractory powder.

Mineral Insulated Type K Thermocouples with Inconel Sheaths are used.

Beyond 1200 deg C, Type S or R Platinum Thermocouples are used.

Resistance Temperature Detectors (RTDs):

RTDs are used where the temperature to be measured are not very high and generally up to 500 deg C.

Pt-100 RTDs are very widely used. They come with 3 & 4 wire configurations. The RTD sensors are thin film, Class A type which are very stable, accurate and reliable. 

Eureka Engineering manufactures RTD Assembly with Suitable Thermowells and Protection Sheaths.

Clinker Cooler & Bag House:

Temperature is not high after Clinker is cooled and inside bag House. So, RTD Pt-100 is used. RTDs precisely monitor Bag House Temperature and improve Filter Bag conditions. Our RTDs meet Class A & B – accuracy as per ASTM E 585, IEC 584. Various Protection Sheaths and Thermowells are available, such as SS 304, 316, Hastelloy.

Flue Gas Temperature:

RTDs with Stainless Steel Protection sheaths are ideal for Discharge Chimneys.

Continuous monitoring of Flue gas temperature is indispensable. 

Highly reliable Pt-100, 3 wire RTDs are manufactured by Eureka Engineering 

Motor Bearing, Gear Box, winding Temperature:

Motors, Pumps are protected by using RTDs to measure Temperature accurately 

Different styles are designed and manufactured by Eureka Engineering. They are Thin Film RTDs- 2, 3 4 Wire configurations, Fast response type, Miniature Spring loaded & Vibration proof.

Infrared -Non-Contact Thermometer:

Thermocouples and RTDs are used at various stages of the Cement manufacturing process. However, the Rotary Kiln Shell temperature can be measured by a Non-Contact Thermometer. Monitoring the Kiln Shell Temperature is critical. Failure of inside Refractive Bricks will lead to hot spots on the Kiln shell. New advanced Thermal Imaging systems provide early detection of hot spots to prevent damages.

Transmitters:

In Cement Plants, Distributed Control Systems (DCS), PLCs and other control systems are located in Control rooms, which are far away from Sensors that are mounted in Process Equipment. Due to this long distance between the process plant and control room, Head Mount Transmitters are essential for accurate measurement of Temperature.

Temperature Transmitter is an Instrument that connects Thermocouples & RTDs to the measuring and Control Instrumentation. It converts the temperature sensor's low-level (ohm & millivolt) signal to a standard 4 to 20 mA.

Eureka Engineering supplies head Mount Transmitters which accept all Types of Thermocouples - K, N, J, R, S. etc and RTDs. These are Universal Programmable range Transmitter instead of Fixed Range.

These are P C Configurable, which is an Easy, Fast and versatile selection of linearization tables.

If it is for Hazardous Area, it is certified as per Standards like Eexd, Exe, IEC EX Certification.

It is also protected against EMI/RFI and isolated signal.

Thermocouple & RTD Cables: 

Cables interconnect the Sensors to Control rooms, measuring and Control Instrumentation system. Right types of cables are to be used to avoid measurement Error and Failure, by using Thermocouple Extension, Compensating Cables and RTD cables.

Eureka Engineering stocks and supplies these cables with a wide range of Insulations to suit the ambient Temperature and Process conditions. These are:

Fire Retardant PVC: 105 Deg C; FEP / PTFE – Teflon: 260 Deg C 

Fibre Glass:  700 Deg C Ceramic Fiber: 1000 Deg C.

To Conclude, Eureka Engineering, with vast experience in Cement Industries, made possible to provide engineered solutions to temperature measurements.

Our continuous endeavour in identifying new Sheath materials and upgrading the technology has made possible high-quality products.