JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech III INSTRUMENTATION PRACTICES IN INDUSTRIES Previous Question Paper (March - 2021 - R18)

Corrosion in cement plants is primarily caused by the aggressive chemical environment, including exposure to high temperatures, moisture, and chemical agents like chlorides, sulfates, and sulfur oxides present in the raw materials and fuel. The abrasive nature of cement dust combined with humidity leads to electrochemical corrosion on kiln shells, cyclones, and ducting. Additionally, the presence of acidic gases from the combustion process accelerates the degradation of metallic structures.

The Electrical Resistance (ER) method monitors corrosion by measuring the change in electrical resistance of a metal probe exposed to the same environment as the plant equipment. As the probe corrodes, its cross-sectional area decreases, causing its electrical resistance to increase. The probe is typically part of a bridge circuit, and the change in resistance is proportional to the metal loss. By periodically measuring this resistance, the corrosion rate can be calculated over time, allowing for real-time monitoring and predictive maintenance of critical plant components.

The primary objectives of measuring compressive strength are to ensure structural integrity, verify that materials meet design specifications, assess the load-bearing capacity of components, and ensure safety in industrial applications. It helps in quality control during manufacturing and determines the suitability of a material for specific environmental stresses.

The apparatus required for this measurement typically includes:

• Universal Testing Machine (UTM) or a dedicated compression testing machine capable of applying a uniform, gradually increasing load.
• Load Cell or Pressure Gauge to accurately measure the force applied to the specimen.
• Extensometer or Deflectometer to measure the deformation or strain of the material under load.
• Specimen Molds to ensure standardized shapes (e.g., cubes or cylinders) for consistent testing.
• Data Acquisition System to record and plot the stress-strain curve.