Case Studies

Flint Hills Resources Propylene Facility, Houston, Texas


Location: Houston, Texas
Owner/Operator: Flint Hills Resources

Flint Hills Resources owns and operates the world’s largest propane dehydrogenation facility, based on production capacity, strategically located on the Houston Ship Channel. The facility, which began operations in October 2010, has an annual production capacity of approximately 1.45 billion pounds. The plant utilizes CATOFIN® propane dehydrogenation technology which is a unique process for the production of olefins, such as propylene (from propane) and iso-butylene (from iso-butane).

HGC Engineering was contracted on two separate occasions (when the complex was known as PetroLogistics) to measure sound and vibration levels at the facility, and provide subsequent analysis and mitigation recommendations.

Petrochemical Facility Noise Investigation and Control Upgrades

HGC Engineering was first contracted in 2011 to investigate and remedy the cause of excessive noise levels from four Rolls Royce “Avon” gas turbine engines that are used to heat propane in the process of converting it into polypropylene.  The noise issues were only occurring when the engines were in initial “bypass” mode, venting to atmosphere, before reaching the designated operating conditions at which time the hot exhaust gasses are then routed into the production process.

Sound intensity methods were used to isolate the sound emitted by each component of the gas turbine engines and exhaust systems, including the ducting, bypass damper, silencer walls and the exhaust outlet (with and without the silencer in place). Overall sound levels were also measured at neighboring residential properties. The measurements identified elevated sound levels as a result of an orifice ring that had been installed upstream of the silencer. Noise control upgrades were made to the system, based on the measurement results.

Compressor and Piping Vibro-acoustic Measurements and Dynamic Finite Element Modeling

We were retained once again in 2012 by S&B Engineers and Constructors, on behalf of PetroLogistics, to investigate vibration and noise levels from one of the compressors on site, and its associated piping, which had apparently increased after modifications to the impeller, and were anecdotally perceived as excessive by personnel on-the-ground at the facility.  The purpose of our investigation was to ascertain whether the levels were problematic with regard to the long term health of the machine and piping, or indicative of a problem with the compressor, and to investigate options for corrective measures.

Our work included vibro-acoustic measurements of the compressor and piping to supplement stress analysis using dynamic finite element modeling. The vibration data was analyzed using a Fast Fourier Transform (FFT) spectrum. The extraction and suction piping were the primary focus of this investigation. Measurements were conducted at several dozen locations along the piping. Sound levels around the compressor and associated piping were measured using a precision sound level meter, equipped with real-time frequency analysis capabilities.

Our analysis concluded that turbulence within the piping was not contributing to any low-frequency vibration issues. No significant low-frequency vibration was noted on the suction, extraction or discharge piping, so no modifications to the main supports for the piping and the compressor were warranted from a vibration perspective. The sound levels in the vicinity of the compressor and associated piping were high enough to warrant double hearing protection for workers, but were not atypical for a compressor of that capacity and thus did not, in of themselves, indicate a problem with the system. It was therefore recommended that sound levels be reduced using appropriately selected acoustical lagging for the piping.

Acoustical Engineering Services Included:
  • Noise and Vibration Investigation and Analysis
  • Vibro-acoustic Measurements
  • Stress Analysis using Dynamic Finite Element Modeling
  • Noise and Vibration Control Recommendations

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