Brief Analysis on Steam Tracing Design for Ortho Phthalic Anhydride Plant
The melting point of phthalic anhydride is relatively high.In the production process,once the medium temperature is below the melting point,liquid phase phthalic anhydride will crystallize in pipelines and equipment,causing blockage.Due to the presence of impurities such as phthalic acid in crude phthalic anhydride,the required heat tracing temperature needs to reach 250 ℃.Generally,the concealed jacket(full jacket)is used for heat tracing with inner pipe welds.This paper introduces the jacket heat tracing and pipe heat tracing methods for pipelines,equipment nozzles and expansion joints in the phthalic anhydride plant.The pipeline heat tracing section focuses on the two forms of ordinary pipeline jacket heat tracing,semi jacket and full jacket,as well as the selection of pipeline test pressure.This paper introduces the calculation method for the number of heat tracing pipes in high temperature and large diameter pipelines where table lookup is not possible.The equipment section introduces three common forms of equipment nozzle heat tracing:ordinary nozzle jacket heat tracing,PAD nozzle jacket heat tracing and PAD nozzle half pipe heat tracing.In addition,the heat tracing method of pipeline expansion joints is also introduced.Finally,in response to the actual situation of a large number of steam tracing users in the phthalic anhydride plant,the advantages and disadvantages of integrated steam distribution stations and condensate recovery stations are compared with traditional forms.
phthalic anhydridejacketed heat tracingheat tracing pipesintegrated heat tracing system
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