Chemical

Industries: Chemical

The chemical industry comprises the companies that produce industrial chemicals. Central to the modern world economy, it converts raw materials (oil, natural gas, air, water, metals, and minerals) into variety of different products. “Polymers and plastics, especially polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, polystyrene and polycarbonate comprise about 80% of the industry’s output worldwide”. These materials are often converted to fluoropolymer tubing products and used by the industry to transport highly corrosive materials.

Chemicals are used in a lot of different consumer goods, but they are also used in a lot of different other sectors; including agriculture manufacturing, construction, and service industries. Major industrial customers include rubber and plastic products, textiles, apparel, petroleum refining, pulp and paper, and primary metals. Chemicals are nearly a $3 trillion global enterprise, and the EU and U.S. chemical companies are the world’s largest producers

Heat Exchangers in Chemical Plants

Heat Exchangers are usually considered to be an accessory piece of equipment in chemical plants. In the reaction system, the large and costly reactor, though a heat exchanger, assumes the prime position of importance. The large systems, which provide the heat sources and sinks-steam refrigeration and cooling water-all appear to be more significant than the lowly heat exchanger which stabilize the operation of the plant by recovering heat or transferring it from source to sink. A look at the total investment in equipment for a chemical plant, shows that heat exchangers are probably the most important pieces of equipment and therefore should require the most engineering attention

If a heat exchanger does not provide the desired temperature of feed to the reactor, then less heat is recovered in the form of process steam and more heat is rejected to cooling water. If feed preheater to a distillation column does not perform in accordance with its design, additional steam is required in the reboiler and additional water is required in the residue cooler. Because there are usually several interrelated heat exchangers in a system, there is a compounding influence of the malfunction of one or two exchangers so that is often difficult to pinpoint the source of deficiency in attaining plant capacity.

Heat Exchanger Failure Mechanism
  • Process corrosion
  • Stress-corrosion cracking (SCC) of tubes
  • Steam/condensate corrosion
  • Process fouling
Three main areas for improvement to minimize future in-service tube failures.
  • Tube testing
  • Retubing strategy during turnarounds
  • Design improvements.
Tube testing

Technologies for inspecting heat exchanger tubes are rapidly changing and continuously improving. Variance in test results depending on both the instrument and operator. The impact of human factors on non-destructive examination (NDE) performance is more prominent with the increased complexity and sophistication of today`s NDE techniques. Root cause analysis of some of the tube failures identified the need for reliable technicians and technologies. APRIS provides solution to tube inspection problems with important advantages to chemical industry by minimizing downtime and improving operational productivity.

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