Process lines, piping engineer

The piping engineer oversizes process lines to avoid being branded an enemy of the people. 

As a direct companion of the completed flowsheet, the line schedule sheet transmits the process and mechanically necessary details for proper interpretation of the piping aspects of the flowsheet (see Figures 1-24A, B, C, D). These schedules are initiated by the process engineer to further explain the requirements of the process as shown on the flowsheets. They are often and perhaps usually cooperatively completed by other engineers, particularly the piping, mechanical and instrumentation groups. 

Electrochemical On-Line Corrosion Monitoring On-line corrosion monitoring is used to evaluate the status of equipment and piping in chemical process industries (CPI) plants. These monitoring methods are based on electrochemical techniques. To use on-line monitoring effectively, the engineer needs to understand the underlying electrochemical test methods to be employed. This section covers many of these test methods and their applications as well as a review of potential problems encountered with such test instruments and how to overcome or avoid these difficulties. 

The problems of two-phase gas-liquid flow in pipe lines have become of greater concern to engineers in recent years. This type of flow is encountered in an increasing number of important situations, and a clear understanding of the rates of transfer of momentum, heat, and material will be required for logical and careful design and operation of a very wide variety of chemical engineering equipment and processes. 

Leung, J.C. (1996) Easily size relief devices and piping for two-phase flow. Chemical Engineering Progress, 12, 28-50. Schmidt, J. and Giesbrecht, H. (2001) Evaluation of uncertainties for safety valve vent system compared to a model-based on-line vessel protection in a (certified) process controller, in ECCE-3, Nuremberg Germany. 

Based on initial heat flow calorimetry studies, a process development engineer must choose the appropriate reactor vessels for pilot plant studies. A pilot plant typically has vessels that range from 80 to 5000 L, some constructed of alloy and others that are glass lined. In addition some vessels may have half-pipe coils for heat transfer, while others have jackets with agitation nozzles. A process drawing for a typical glass-lined vessel is shown in Figure 4. In Sections 3.1.4.1 and 3.1.4.2 we review fundamental heat transfer relationships in order to predict overall heat transfer coefficients. In Section 3.1.4.3 we review experimental techniques to estimate heat transfer coefficients in process vessels. 

Pipe-line and marine installations are frequently arranged so that the engine drives all its auxiliaries from the crankshaft by means of chains and V belts. But process-plant practice is to have all the auxiliaries independently driven, using standby pumps to minimize engine downtime. 

Trace elemental analysis can also be used to indicate the level of contamination of middle distillate fuels, e.g. turbine fuels. Metal contamination can cause corrosion and deposition on turbine components at elevated temperatures. Some diesel fuels have specification limits to guard against engine deposits, however they sometimes employ Mo or Ni as a catalyst for the refining process which eventually ends up in the finished products. There are several sources of multi-elemental contamination in naval distillate fuels. Sea water is pumped into the diesel tanks as ballast to immerse ships and submarines. Some oil transport ships have dirty tanks and contamination and corrosive products can also come from piping, linings and heat exchangers. 

The outstanding property of rubber in general is resilience, or low modulus of elasticity. The flexibility and physical properties of rubber account for its application in general engineering and automobile industries whereas its chemical, wear and abrasion resistance as a sacrificial material, plus its insulating properties are utilised in many corrosion and erosion applications in process industries. Rubber lined mild steel, pipes and tankages have been standard materials of construction for hydrochloric acid service for many years. 

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