Project Profile
Dust Hazards Evaluation for Installation of New Equipment
Read how ABS Group helped a major chemical company understand the dust hazard risk for a new piece of equipment being installed at the plant
Project Objectives
#1
Identify the blast and fire hazards associated with the new tool
#2
Produce a limited 3D model of the room, including walls, doors and windows
#3
Produce a guidence document for the client to help them see at what point each failure became a risk
Project Overview
A chemical client was implementing a new piece of equipment. The client needed support understanding the generalized risks relating to blast and fire. The current Process Hazard Analysis (PHA) identified several credible scenarios for the potential loss of containment of a hybrid mixture of carbon powder, CO, and CO2.
These releases have the potential to produce multiple fatalities/injuries to personnel near, adjacent, or outside due to the subsequent fire and/or explosion. Additionally, these releases may damage neighboring equipment initiating a knock-on effect.
Client Needs
- A guidance document expounding the points at which each failure became a risk.
- Understanding the explosion and fire risks associated with their new tool
Our Solution
The client requested our assistance in resolving a variety of action items by evaluating explosion and fire events that the new tool could potentially initiate. Additionally, the client requested the use of modeling and analysis methods that do not require full 3D representations of the equipment and production floor area. More detailed modeling methods utilizing a 3D model could further refine the presented results.
The Model
The hazards analysis required the generation of a limited 3D model, per the client's request. This model focused on both exterior and interior walls and windows surrounding the production floor with limited internal equipment included.
Structural Hazards
Damage and blow-out conditions for the walls and windows were established using a pressure-impulse (P-i) diagram approach. Response criteria for conventional structural components are defined by U.S. Army Corps of Engineers (USACE) Protective Design Center (PDC) technical report PDC-TR 06-08 and Single-Degree-of-Freedom Response limits for blast. The overall building response was determined by first predicting the response of each component and then evaluating them collectively. Structural components are divided into primary and secondary categories to determine the limits of response and Building Damage Level (BDL), which can be associated with personnel safety.
Explosion Hazards
The model was imported into the commercially available industry-standard software FLame ACceleration Simulator (FLACS) for the advanced modeling of a variety of hazard phenomena. The blow-out conditions for walls and windows were assigned to each panel representing these surfaces. Each panel recorded its time-dependent history regarding pressure, impulse, and blowout. The dust explosions required surrogates to mimic the combustion and pressure production for the dust as provided by the client. ABS performed CFD dust explosion modeling for eleven dust mass cases: 51g, 75g, 100g, 550g, 1,000g, 5,500g, 15,000g, 25,000g, 45,000g, 80,000g, and 105,000g.
Thermal Hazards
For the thermal analysis, ABS did not use the simplified 3D model, instead, Process Hazard Analysis Software Tool (PHAST) was used to generate the thermal flux contours based on the dust volume pre-combustion footprint and the surface emissive power. The surface emissive power of the dust fire flame surface was conservatively estimated to be 170 kW/m2. This value is based on a comparison between the client’s carbon dust properties and materials evaluated in the literature [6]. Thermal effects on personnel and equipment are a function of thermal flux and duration. The thermal exposure was based on the total combustion time from the FLACS explosion modeling.
Value Delivered
This project was different from typical hazard evaluations as it was not confined to specific regulatory or client guidelines. It was an exploratory exercise to understand what the hazards could be. Therefore the value for the client was to gain a better understanding of the risks that their new equipment could pose to their staff and facilities. ABS Group provided the client with a table showing the escalating hazards for the affected areas based on dust mass, allowing the client the ability to form their own risk matrix.