Whilst I dont know much about materials selection, would suspect you would need to heat trace and insulate this pipeline to keep the pipewall temp above water dewpoint temp. This is to prevent water condensation and fluctuating backpressure on the upstream stripper due to hydrodynamic slugging. You may also need to state if there are other impurities such as ammonia in the stripper overheads stream from the reflux drum - ammonium hydrosulfide / sulphide solids can build up in the line and increase pressure drop.

Dear shahabemk,

Carbon steel is normally used (ASTM A 106 Gr B) for such a "hazardous" service.

Regards.

DHURJATI SEN
Kolkata, India

I suggest getting a consultant familiar with the subject , hydrogen sulfide can get you into a lot of problems. Starting with API 5L you will need several pages of additional requirements : As an example, hardness limits in weld zones , type of hardness tests, frequency of hardness tests , location of hardness tests, etc. You will need to decide if HIC tests are needed ( Nace method, I forget the number). Depending on your location I very much expect the pipeline will need to be in conformance with NACE MR 01-75 ( ISO 15959 , as I remember). I would avoid ASTM specifications as the quality assurance requirements are not comprehensive.

The typical pipeline is to be B31.4 or B31.8 Code work. The detail design should be based on the process condition, pipeline route, as well as the local rule and regulation, etc. The material is to complied with NACE 01-75 as a must. Consider to have the adequate isolation valves along the pipeline as required for pigging, maintenance or emergency.