Dr Greg Palmer

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Research / Non-destructive Testing

Testing the Integrity of Refractory Lined Vessels using the NDT Technique P-Response ®

The P-Response® system is a fast screening method for identifying suspect areas of civil and refractory concrete, non-destructively, as opposed to visual inspection or core drilling. The impact-echo technique (P-Impact) can be used to verify suspect areas. The P-Response® technique has been adapted to test refractory concrete and/or brick linings in process vessels for the cement, petroleum, petrochemical, minerals, alumina (plus other) industries and can be used to determine refractory lining stability and quality from the outside of the vessel.

Introduction
Assessing refractory lined vessels in cement plants, eg cyclone roofs, is a serious issue for maintenance managers. Assessing the condition of vessel linings has generally been carried out visually. Visual inspection obviously cannot detect if a refractory lining has failed at the interface allowing a section to fall while personnel are working in the vessel. Palmer Technologies has recently carried out an assessment of refractory lined vessels using the P-impact and P-response® techniques.

The P-Response® system is a fast screening method for identifying suspect areas of civil and refractory concrete, non- destructively, as opposed to visual inspection or core drilling.

The impact-echo technique (P-Impact) can be used to verify suspect areas. The advantage of the P-response® test is that it is a fast test method and can be performed on relatively rough surfaces. In a thin plate, like a vessel lining or concrete floor, the impact from the modal hammer will induce a vibration (flex) over a small area which is directly related to the elastic modulus and thickness.

The flexibility of the plate is measured by a transducer (geophone) and the frequency response is normalized by the impact force. The mobility from one location to another is compared as part of the assessment.

The assessment of the refractory lining condition before entry is a significant safety issue as unstable slabs of refractory concrete can cause severe injury to personnel entering the vessel.

The P-Response® technique has been adapted to test refractory concrete and/or brick linings in process vessels for the cement, petroleum, petro-chemical, minerals, alumina (plus other) industries and can be used to determine refractory lining stability and quality from the outside of the vessel.