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Guide to Process Scale Up - Process Safety Explained

Posted by AnnMarie Fauske on 04.04.19

Hazard Identification and Risk Analysis

From time to time, plants and facilities in every industry of manufacturing or production will need some sort of testing and engineering consulting services to identify hazards related to the handling or storage of flammable and combustible liquids and gases, combustible dust and reactive chemicals.  

When a process is new, moved to a larger scale, or has never been studied, a reaction calorimetry study should be completed on the desired chemistry to understand how it should be properly handled. The Process Hazard Analysis (PHA) identifies potential hazards associated with a material. If there are any questions about material behavior, then testing is needed.

Extensive testing experience allows one team to identify potentially hazardous conditions that may not be readily discernible.  Benefits of using one group include:

  • Understand and address hazards that pose the highest level of risk to your process facilityGuidetoProcessScaleUp2

  • Ensure compliance with relevant national, local and industry standards

  • Implement best engineering practices

  • Reduce overall level of risk

  • Increase productivity and employee morale

  • Make organization more competitive

  • Decrease insurance premiums



Safer Process Scale Up

A comprehensive engineering testing lab will offer services for safer scaling up of batch, semi-batch and continuous processes.  Consultation is available for process development groups involved throughout the development cycle.  Areas of expertise include the following topics: 

  • Onsite or desktop review
  • Determine critical process parameters to avoid or mitigate unwanted reactivity
  • Development of customized scale-up program designed for safer operation at various stages
  • Perform calorimetry testing to characterize desired and undesired reactions
  • Identify safe operating limits for temperature, pressure and other safety-critical parameters
  • Emergency relief design calculations for pilot plant, kilo lab and commercial scale equipment
  • Independent safety assessment,
Adiabatic Calorimetry & Relief System Design

Adiabatic calorimeter testing provides data for relief system design, safe scale up of chemical processes, and changes to process recipes.  Safe process design requires knowledge of chemical reaction rates, character and energy release - all of which can be obtained from a low phi-factor adiabatic calorimeter such as the VSP2™ (Vent Sizing Package 2) or ARSST™ (Advanced Reactive System Screening Tool).

The VSP2 ™  and the ARSST  - both developed by Fauske & Associates, LLC (FAI) as the principal research contractor for the Design Institute for Emergency Relief Systems (DIERS) under AIChE - provide thermal data required for safe scaling up of chemical processes and changes to process recipes. A variety of process upset conditions can be tested to quantify hazards identified by a Process Hazards Analysis or HAZOP study. The low phi-factor (or thermal inertia) allows the heat and gas generation rates to be measured and directly applied to the process scale, which leads to appropriately designed emergency relief systems.

Reaction Calorimetry

One of the keys to safely scaling up a chemical process is managing the energy or heat flux that the intended chemical reaction produces, especially when that chemical transformation is exothermic in nature. When considering process scaling up whether the heat is removed via a jacket, a condenser, or a side loop heat exchanger in the plant reactor or partially allowed to heat up the mass, it is imperative to balance the cooling capacity at scale versus the projected heat flux rate and understand the total energy available due to the desired reaction should that cooling fail. The accepted technique for gathering this type of data in the industry is known as reaction calorimetry.

There have been many instruments developed over the years to accomplish this task and comprehensive labs such as FAI maintain a variety of devices so that we can design the most appropriate experiment to gather the vital heat rate and adiabatic potential data needed for safely scaling up. Couple this with vast experience in characterizing runaway reaction behavior using adiabatic and vent sizing calorimetry and we deliver a complete picture of a safe chemical process.

Thermal Stability

Thermal stability testing aims at collecting reaction rate data and applying that data to assess whether a specified quantity of material can be used in a way such that runaway reactions are avoided.  This is important when considering processing, long-term storage, or shipping of a material.

A variety of instruments and tools can be used to characterize the thermal stability of a material:

  • Differential Scanning Calorimetry (DSC)
  • Thermogravimetric Analysis (TGA)
  • Accelerating Rate Calorimetry (ARC)
  • Thermal Activity Monitor (TAM)
  • AKTS-Thermokinetics Software
  • Advanced Reactive Systems Screening Tool (ARSST)
  • Vent Sizing Package 2 (VSP2)
  • C80 Calorimeter manufactured by Setaram

Accurate determination of safety parameters:

  • Onset Temperature
  • Kinetic Parameters
  • Time to Maximum Rate
  • Critical Temperature / Temperature of No Return
  • Self Accelerating Decomposition Temperature

Process Hazards Analysis (PHA)

A PHA is a systematic evaluation of the hazards involved in the process.  They are required for initiation of a process and at least once every five years after that.  It is important to address normal operating conditions as well as start-up, normal shut down and emergency shutdown procedures during the PHA.  The team should be multi-disciplinary, including operations, engineering and maintenance.  To properly conduct a Process Hazards Analysis, the process safety information (PSI) must be as complete as possible.  FAI provides services including auditing / review, revalidating and facilitating. 

FAI has performed PHAs for compliance to OSHA PSM requirements as well as combustible dust related for compliance per national National Fire Protection Association (NFPA) guidelines: NFPA 654, NFPA 664 and NFPA 484.  Using a variety of techniques including, hazard and operability (HAZOP) analysis, what-if, checklists, failure modes and effects analysis (FMEA) as well as quantitative risk assessments such as layer of protection analysis (LOPA), FAI provides a full range of services. 

Process Safety Management (PSM) Program Development and Support

A one-stop engineering and lab firm can review or develop process safety programs to support chemical manufacturing facilities or development programs.  This can be performed for facilities including a kilo lab, pilot plant, medium scale and commercial scale plants.  Services include:

  • Auditing, reporting and presenting
  • Gap assessment to identify and prioritize needs
  • Process validation
  • Safe scale-up guidance
  • Development report documentation
  • Consulting on process safety issues for change control (management of change)

For more information on safe process scale up or process safety, please contact info@fauske.com or 630-323-8750

Guide to Process Scale Up

 

Process Safety Management (PSM) Overview

Topics: process safety, PHA, scale up

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