Combustible Dust Emergency Relief System Evaluation

The Challenge

A global manufacturer of specialty minerals and fertilizers was evaluating starch, a new product to their facility, which contained combustible dust. The client wanted to ensure full protection for their equipment while processing this new material. In accordance with the prescriptive measures of NFPA 654, all equipment handling combustible dusts should be provided with explosion protection. Because their facility already had existing equipment, there were no practical means for reducing oxidant concentrations, and diluting the combustible dust product was not an option. Deflagration venting per NFPA 68 was the best option for explosion protection.

Our Approach

The scope of the Emergency Relief System (ERS) evaluation included the bucket elevators, screw conveyors, blender, sifter, dust collectors, hoppers, and packaging areas. The ioKinetic team examined all applicable scenarios that may overpressure the equipment based on the given P&IDs, consulting with the clients’ designated technical contact as needed. For all of the applicable overpressure scenarios, Process Safety Office SuperChems™ software was used to determine the relief area required to prevent damage to their equipment.

ioKinetic’s typical ERS analysis consists of the following steps: 

  1. Collection of data on the pressure relief system
  2. Evaluation of overpressure contingencies
  3. Determination of required relief rates
  4. Preparation of specification sheet for an appropriate relief device for the application

The Benefits

During the ERS evaluation, the team discussed with the client their management systems including process hazard assessments, maintenance, management of change (MOC), and training. The ioKinetic audit report identified key gaps between the installation and operation of their facility and the compliance requirements as defined in NFPA 654 and delivered 27 recommendations to improve their facility’s compliance to recommended standards and practices. Various alternatives that could be taken through a HAZOP determination of the risk involved were suggested for some of the less obvious scenarios. A listing of the observations against Recognized and Generally Accepted Good Engineering Practices (RAGAGEPs) was included. The client was particularly pleased with the detailed 27 recommendations report, which served as a guide for cost estimates on facility improvements.