(34g) Sulfur Recovery and Tail Gas Treating Process Gas Analyzers, Stigma, Sins and Salvation

Process Engineers have a strong inclination for qualitative and quantitative analysis of process streams.  On-Line process gas analyzers are a fundamental requirement for control, optimization and energy efficiency but have a stigma with end users and maintenance managers, sometimes well earned. 

On-Line process gas analyzers comprise a relatively small share of the capital in a grass roots project but they require detailed attention if they are to be successfully implemented and fully exploited.  The chain is long and the sins are many.  It runs from front end engineering design, to EPC detailed design, through systems integration, selection of technique and vendor, factory acceptance test, start up, handover and a life cycle support strategy. 

The paper discusses several practical aspects of the suite of analyzers utilized on a modern SRU / TGTU installation as well as “best practice” recommendations based on maintenance records and at times, painful experience.  Salvation can be found in the details and by retaining process analyzer specialists at all phases of a project from all sides. 

The intent of this paper is to offer examples based on experience of analyzer engineering and sample handling details.  The subject is one of the least understood facets of a project, the profession is occupied by people from various fields including chemical engineers who have made it their life’s work.  The following topics are covered in the paper: 

• Sample point selection for analyzers; the good the bad and the ugly and why don’t we engage the piping engineer at an earlier stage?
• Why are we buying “real estate”, meaning analyzer houses with the associated HVAC, fire and gas systems?  What direction is this taking?
• Project management; the path from FEED to EPC to analyzer system integrator to specialized analyzer vendor to end user.
• The role of safety in sample handling; process isolation, double block valves
• How analyzer requirements differ between refinery & gas plant do based SRUs?
• Lessons learned from a SRU revamp, adverse process conditions and a compromised sample location.
• A feed forward analyzer for acid gas analysis, what can be expected bring in terms of improved recovery efficiency and mitigation of process upsets?
• Accounting for reduced S compounds after tail gas / tail gas treating incineration, chasing and accounting for that last few ppm of sulfur for the EPA.