About Openso Engineering

Providing Optimum Engineering Solutions

Openso Engineering is a specialized engineering services and fabrication technology company that serves the Petroleum Refining, Petrochemical, Chemical, and related industries.   We are centrally located in the United States near St. Louis, across the Mississippi River in Edwardsville, Illinois.

Our competitive advantage is the ability to combine the latest technology available with many years of practical experience analyzing, designing, and fabricating pressure vessels, heat exchangers, and other process equipment. This combination of technical aptitude and hands on knowledge allows us to react to our customers needs quicker and pinpoint the root cause of problems much faster. This time savings results in overall cost savings to our customers.


OPENSO was founded by four principal employees of Nooter Fabricating with over 120 total years of experience. If you are familiar with NFI, it was a world-renowned fabricator of pressure vessels, heat exchangers, and other process equipment.

Nooter was a pioneer in pressure vessel fabrication, which included fabricating the FIRST TWO ASME SECTION VIII Div 2 Pressure vessels ever manufactured. Our fabrication experience is one of the main advantages we have over our competition, because it allows us to develop a wider range of practical solutions to design issues and failures. Our President, Khalil Rabiei, was the Chief Engineer for Nooter Fabricators Inc. (NFI) and Engineering Manager for Nooter Consulting Services (NCS).

Management Team

Click on a name to learn more about that person:

Khalil Rabiei, President & Principal Engineer

Khalil Rabiei is the Principal Engineer for Openso Engineering.  He has Bachelor of Science, Engineering Mechanics and Material, Southern Illinois University at Carbondale, Master Of Science in Structural Engineering, Southern Illinois University at Carbondale, Post graduate studies in advance Structures at Washington University, St. Louis, MO, Doctoral degree in Mechanical Engineering at Lancaster University. He is a registered Professional Engineer in the states of Illinois, Missouri, Texas, California, Indiana, Ohio, and District of Columbia.  Khalil is also a part time staff member of Southern Illinois University at Edwardsville – Instructor of Mechanical Engineering Department.

Khalil is involved with many professional societies, including:

  • American Society of Mechanical Engineers
  • American Society of Civil Engineers
  • American Society of Professional Engineer
  • American Petroleum Institute (API) Member:
    • Design Committee
    • Joint Committee
    • Fitness for Service Committee

As Principal Engineer for Openso Engineering, Khalil’s leadership helps to guide a project from conception to completion:  consisting of initial technical proposal, quotation for total cost and turnaround time, conducting and performing design and analyses for highly complex problems using linear and non-linear methods, in both classical and finite element approaches, such as: stress/fatigue analysis, vibration analysis, and creep analysis of structures, performing classical discontinuity stress/fatigue analysis, thermal and thermal stress analysis, vibration analysis of structures under wind, seismic and any other dynamic loads.

A List of Khalil’s Publications:

  • Stability of Geodesic Dome Under Symmetric Dynamic Loads.  ASCE April 1995
  • Influence Of Imperfections On Nonlinear Dynamic Response Of Trusses.  ASCE April 1996
  • Comparison of Dynamic Nozzle Loads to Static Nozzle Loads Using Finite Element Analysis, The International Association for the Engineering Analysis Community (NAFEMS) April 2001.
  • The Response of Framed Steel Structure.  Structures Congress 2006
Sepi Sayeh, Chief Financial Officer
  • Bachelor of Science in Electrical Engineering, Southern Illinois University-Edwardsville
  • Master of Science in Electrical Engineering, Southern Illinois University-Edwardsville
  • Chief Financial Officer of Openso Engineering since 2002
Ryan Heuermann, Sales/Project Manager
  • Bachelor of Science in Chemical Engineering, University of Missouri-Columbia
  • In pursuit of Masters in Mechanical Engineering, Southern Illinois University- Edwardsville
  • Certified Engineer In Training (EIT)
  • Engineering Consulting Sales / Project Manager with international experience in petroleum refining, petrochemical, biofuel, polysilicon, pulp & paper, automotive, aerospace, mining, agriculture & other related industries
Ajay Kardak, Principal Mechanical Engineer

Ajay Kardak is a Principal Mechanical Engineer at OPENSO Engineering. Ajay completed his doctoral degree in Mechanical Engineering at Louisiana State University (LSU), Baton Rouge, LA in 2015. After graduating in 2015 he started working at OPENSO Engineering as Senior Design Engineer and then promoted to be Principal Mechanical Engineer based on his technical aptitude and “hands-on” approach. Ajay has managed multiple projects, simultaneously, that involved a combination of hand calculations, Finite Element Analyses (FEA), developing client reports and proposing appropriate recommendations. He has traveled extensively within the U.S. and internationally providing “hands-on” support in resolving client’s issue. He is adept in performing Structural/Thermal analysis, Vibration analysis, Fatigue Life predictions, Buckling analysis, Creep analysis, Pipe Flexibility analysis using various numerical methods. Ajay has in-depth knowledge of various ASME, ASTM, API Codes and Standards. He is a highly regarded senior-level mechanical engineer with a record of technical innovation and multimillion-dollar cost saving accomplishments. Ajay is also a professional member and contributing author of various peer reviewed ASME and ASTM journals. He is also a reviewer for ASME’s prestigious Journal for Verification, Validation and Uncertainty Quantification. Ajay received his Master of Science Degree in Mechanical Engineering from Louisiana State University (LSU), Baton Rouge, LA. Before coming to United States (U.S.), Ajay received his bachelor’s degree in Mechanical Engineering from India. His areas of expertise include Finite Element Analysis (FEA), Computer Aided Design (CAD), Computational Mechanics, Contact Mechanics, Fracture Mechanics, Experimental Mechanics, Structural Dynamics, Pressure Vessel Design and ASME Section VIII Division 1 & 2.

Shrey Shah, Senior Design Engineer

Shrey Shah is a Senior Design Engineer at OPENSO Engineering. Shrey graduated with a Master’s degree in Mechanical Engineering from the University of Texas at Dallas (UTD), and joined OPENSO after his graduation, where he has contributed significantly to a number of projects. Shrey’s interest lies in performing practical modeling and simulation of various physical processes and phenomena. He is proficient in performing static and transient analyses applicable to single-phase and multi-phase fluid flow, vibrations, thermal and structural simulations in a timely and organized manner. He is experienced in various ASME and API standards used to carry out fitness for service and fatigue life calculations. He is also adept at writing programming codes in MATLAB, C and Python. His Master’s thesis was based on numerical modeling and simulation biomedical devices and underwater robots. His research included non-linear structural analysis of shape memory alloys (SMA) for a cardiovascular stent and underwater simulations of octopus and jellyfish movement using user-defined functions. Before coming to the United States, Shrey obtained his Bachelor of Technology in Mechanical Engineering from the Indian Institute of Technology Gandhinagar. During his bachelor’s degree, he also accomplished a Minor in Computer Science and Engineering. Shrey’s expertise lies in Computational Fluid Dynamics (CFD), Finite Element Analysis (FEA), Fluid-Structure Interaction (FSI), multi-phase flows, heat and mass transfer, Computer-Aided Design (CAD), MATLAB, Python, user-defined functions, fitness for service, fatigue analysis, boiler and pressure vessel design.



We offer services that include Finite Element Analysis (FEA, Computational Fluid Dynamics (CFD), vibration analysis, failure analysis, fatigue analysis, wind/seismic analysis, Fitness For Service (FFS), pressure and heat exchanger design, and re-rates.


Openso Engineering is the worldwide licensee of Nooter Corporation entitled to use, market, and sub-license Nooter Corporation’s proprietary methods, techniques, and know-how for the design, analysis, fabrication and testing of pressure vessels and heat exchangers made from titanium, zirconium, titanium clad (single and double integrity), zirconium clad (single and double integrity), tantalum clad, and quench annealed Hastelloy B-2 with Plywall wraps. Our services also include metallurgy, failure analysis by metallurgy, welding, fabrication, forming, non-destructive examination, heat treatment and testing procedures, as well as investigating fabrication problems.

Openso Engineering recognizes the imperatives of our competitive age – speed, low cost, and high quality – in our engineering and fabrication technology services. Openso Engineering strives to provide the optimum solution that is realistic, resourceful, and cost effective, through our knowledge and insight.

Industries Served

  • Petroleum Refinery
  • Petrochemical Industry
  • Chemical Industry
  • Metal Fabrication
  • Polysilicon Industry
  • Paper and Pulp Industry

Partial Client List

  • Arizona Chemical
  • BP
  • Celanese Ltd.
  • Chattanooga Boiler & Tank
  • Chevron
  • Chicago Bridge & Iron (CB&I)
  • Continental Fabricators Inc.
  • Eastman Chemical
  • Evonik Industries
  • Formosa Chemicals
  • Foster Wheeler
  • GT Advanced Technologies
  • Hantech
  • Hemlock Semiconductor Corp.
  • LyondellBassell
  • INEOS Technologies
  • International Paper
  • Kennedy Tank
  • Marathon Petroleum Company
  • Nooter Construction Company
  • Phillips 66
  • SABIC Innovative Plastics
  • SG Solutions
  • Southern Heat Exchanger Corp.
  • Valero Energy Corporation
  • Watlow Electric