Understanding the Key Hazards of the Biofuel Industry

Like other industries, the biofuel sector has common hazards and potential consequences related to dust explosion threats, handling flammable liquid processes and storage, and toxic or corrosive materials handling. The risk level associated with a catastrophic event can be easily reduced with proactive, well-established risk management practices and safeguards.

In this newsletter, Judy Perry , CCPSC, discusses the key catastrophic hazards, historical incidents, and applicable regulatory standards.

Mrs. Perry is a Certified Process Safety Professional with more than 35 years of broad-based chemical and pharmaceutical industry experience and more than 30 years of experience in process safety and operations management. Her extensive background includes Plant Director of Operations at a high hazard batch facility, global process safety and loss prevention leadership, project management, continuous improvement, quality management, and personnel safety and health regulations.

Key High Hazards

Nearly every operating ethanol manufacturing facility in the biofuels industry has at least three high hazards that, if not properly safeguarded, have the potential to have catastrophic consequences. Dust explosions and flammable liquid fires/explosions are two of the hazards (with catastrophic potential) that are common to all facilities, regardless of technology. Both issues are so prevalent that Occupational Safety and Health Administration (OSHA) has established National Emphasis Programs (NEP) for these risks.

Depending on the technology, typically these facilities use another hazardous compound.? Examples of other hazardous chemicals include anhydrous ammonia, aqueous ammonia, sulfuric acid, chlorine, sulfur dioxide, or caustics. Each of these compounds is highly hazardous and should be managed accordingly. Ammonia is one of the more common compounds utilized by ethanol manufacturers, which can be present in the anhydrous or aqueous state. Anhydrous ammonia has a much higher potential for a catastrophe than aqueous ammonia. As a result, this paper specifically targets the risks associated with anhydrous ammonia, the third high hazard.

These three high hazards have a relatively low frequency for a catastrophic event; however, the potential consequences are very high. This results in an overall high risk for bioethanol manufacturers. The good news is that the risk level associated with a catastrophic event can be easily reduced with proactive, well-established risk management practices and safeguards. As previously mentioned, the safeguards for each of these hazards have been established for years and have proven to be very successful in preventing incidents.

The potential severity of each of these hazards is well established by historical evidence. In addition, each hazardous chemical is subject to extensive regulatory requirements established by OSHA, the US Environmental Protection Agency (EPA) , and the Authority with Jurisdiction (AWJ). An incident involving any one of these hazards has the potential to impact the environment, cause personal injury, cause a significant business interruption and/or property damage, and has the potential to impact the entire industry.

Dust Explosion Hazards

The first high hazard to be discussed is also one of the first to be encountered in the start-up process. Dust explosion hazards are typically present in the feedstock area of the facility. One of the primary feedstocks for bioethanol production is corn.

There have been numerous recorded catastrophic incidents in the grain handling facilities. The most significant agricultural disaster happened on June 8, 1998, when seven employees of the DeBruce Grain Elevator Company were killed by a dust explosion. The initial grain elevator explosion occurred when grain dust was ignited in the east tunnel of the south array of silos. This set off a series of secondary explosions of increasing severity. In response to this incident, OSHA issued the 29 CFR 1910.272 Grain Handling Facilities Standard. This standard focuses on requirements for controlling grain fires, grain dust explosions, and hazards associated with entry into bins, silos, and tanks. The introduction of the standard led to significantly reducing the number of catastrophic events at agricultural facilities.

The requirements of 29 CFR 1910.272 should be well understood by all biofuel manufacturing facilities that handle grain as a feedstock; however, the dust dangers associated with other nonagricultural feedstocks are not addressed by this standard. Take note that a new sense of urgency is spreading across the U.S. over dust explosion hazards, as discussed in further detail below.

A report on the topic of dust explosions in industry was issued by the U.S. Chemical Safety and Hazard Investigation Board in 2006. Over a 25-year period, the board identified 281 fires and explosions that resulted in 119 fatalities and 718 injuries. Despite the findings of the CSB report, facilities were not taking the necessary key steps to be proactive in the prevention of dust explosions.

Another catastrophic event reiterated to all industries that dust hazards are a very serious issue. On February 7, 2008, an incident occurred at the Imperial Sugar Refineries in Port Wentworth, Georgia, resulting in 14 fatalities and many more injuries. This explosion reaffirmed the need for a change in methodology for managing this hazard.

Many of the codes and standards that were just considered good practice at the time have since been adopted as legislation by OSHA via the use of NFPA codes or other related OSHA regulations. This means that if the ethanol production process uses grain as the feedstock, it falls under the OSHA 29 CFR 1910.272 Grain Handling Facilities Standard. If a different feedstock is used, other regulations from OSHA's National Emphasis Program on Combustible Dusts (CPL-03-00-008) would apply instead. This NEP, revised and published in January 2023, would apply to most biofuel manufacturing facilities. OSHA's National Emphasis Program for Inspection of Grain Handling Facilities may also apply, as it is based on the regulations outlined in 29 CFR 1910.272.

It is still common to see headlines of dust fires and explosions in the biofuel industry. Here are a few recent news headlines:

“Firefighters Put Out Dust Collector Fire at Wisconsin Biofuels Producer” WBAY Action 2 News, September 22, 2021.

“Explosion at Illinois Ethanol Plant Causes Grain Silos to Collapse” 25News, May 11, 2022.

“Morning Fire Develops in Dryer at Ethanol Production Plant in Illinois” Starved Rock Media, November 4, 2022.

A catastrophic incident can easily occur, as demonstrated by incident results from industry sectors that did not follow written standards for dust hazards. The biofuel industry should understand and adopt current dust handling best practices, as well as those standards adopted by their Authority with Jurisdiction (AHJ). By adopting a proactive risk management culture, you can significantly reduce the likelihood of catastrophic dust explosions. Any biofuel facility not proactively managing its dust hazards has the potential to be at risk for a catastrophic dust explosion.

Regulations continue to evolve and be more diligently applied as combustible dust events continue to occur across the globe. The NFPA is currently leading the way with a major revision to consolidate combustible dust standards. The new NFPA 660 Standard for Combustible Dusts [1] has replaced many other NFPA standards (652, 654, 61, 484, and 664) that OSHA has incorporated by reference over the last decade. This new consolidated NFPA standard was published in December 2024.

A most critical activity, to ensure each dust hazard is properly safeguarded, is the completion of the required Dust Hazard Analysis (DHA). A DHA is parallel to the well known hazard identification and risk assessment methodologies, otherwise commonly known as a Process Hazard Analysis (PHA) in the chemical and refinery industries. The requirement for a DHA is outlined in the newly published NFPA standard, additionally a good DHA will ensure any design flaws are surfaced and recommendations made to address unacceptable risks identified during the DHA.

Flammable Liquid Hazards

Another high hazard is the explosion and fire potential associated with handling flammable liquids, such as ethanol and the denaturant. Scenarios such as pool fires, vapor cloud explosions, and/or flash fires are among the risks associated with this hazard. The likelihood of a catastrophic event scenario may be low, however, the potential consequences are high.

Evaluating a scenario to determine its consequences and likelihood will likely result in an overall high-risk ranking. Risk assessments of each scenario for all high hazards should be based on an organization’s tolerable risk criteria, criteria that should be based on industry standards. The hazard evaluation methods for developing a risk assessment range from qualitative (e.g., hazard and operability (HAZOP, what-if) to highly quantitative methodologies (e.g., fault tree analysis (FTA), dispersion analysis with impact criteria). Several publications, such as the CCPS LOPA publication and the Guidelines for Hazard Evaluation, cover the topics of hazard evaluation and risk assessment. A trained Process Hazard Analysis (PHA) leader will select a methodology that fits the needs of a biofuels manufacturer. Formalizing the risk assessment process, where risks are documented and addressed, is another example of a practice that is very mature in chemical and refinery businesses, yet lacking in some biofuel manufacturers. Manufacturers of biofuels must make sure that their risk assessments and PHA studies follow industry standards, particularly when dealing with flammable liquid hazards. If an in-house resource is not available, the expertise should be contracted to a qualified organization.

Ethanol is considered a Class IB flammable liquid [2] classification. The tank fire incident on January 24, 2004, at the ethanol plant in Port Kembla, New South Wales, Australia clearly demonstrates the high hazard of ethanol. According to the Australian Associated Press (AAP), “The explosion at this ethanol plant rocked areas over 15 miles away and sparked a huge fire that sent flames and black smoke shooting 328 ft. in the air as the roof was blown off. Cars across the street had taillights that were melted.”

Although the bio-ethanol industry is relatively new, there is over a century of data available that clearly explains the fire and explosion hazards of flammable liquids. The root cause of many of the catastrophic incidents has been identified as poor detailed design practices for handling basic flammable liquids. This is clearly depicted by two recent cases within the same company in a single year.

On July 17, 2007, explosions and fire erupted at the Barton Solvents facility in Valley Center, Kansas, north of Wichita. The incident led to the evacuation of thousands of residents and resulted in projectile damage offsite, as well as extensive damage to the facility. The second incident occurred on October 29 that same year. A fire and series of explosions occurred at another Barton Solvents facility in Des Moines, Iowa. The second incident was caused by a static electrical spark resulting from inadequate electrical bonding and grounding during the filling of a portable steel tank. The CSB investigation determined,

“If Barton had implemented a comprehensive static electricity and flammable liquid safety program, in compliance with current regulatory standards and good practice guidelines, the fire likely would have been prevented. These include OSHA's Flammable and Combustible Liquids standard and codes and recommended practices of the National Fire Protection Association [1].”

Anhydrous Ammonia Hazards

Ammonia has its own unique hazards as well. It is a highly toxic material, with an OSHA permissible limit equal to 50 ppm (8 hours) and an Immediate Danger to Life and Health (NIOSH -IDLH) of 300 ppm. Ammonia is highly irritating to the eyes and respiratory tract. More than a few minutes of skin contact can cause pain and a corrosive injury.

In addition to being acutely toxic, it is a potential fire and explosion hazard. A release of ammonia is of particular concern in highly populated areas. Liquid ammonia will expand by 850 times its initial volume when vaporized. However, anhydrous ammonia is generally not considered to be a flammable hazardous product because its temperature of ignition is greater than 1,560 degrees Fahrenheit and the ammonia/air mixture must be 16 percent to 25 percent ammonia vapor for ignition. Ammonia is much less likely to ignite than ethanol vapor or suspended dust, however, it does have the potential for explosion, particularly in enclosed areas.

Operations and maintenance failures, equipment failures, and process failures are the three leading causes of accidental releases of ammonia. Equipment failures include defective equipment design, construction, and installation resulting in overflowing containers, and leaking piping, valves, and gaskets. Process failures include pressure, temperature, flow, and fluid chemistry changes that result in tank and/or piping ruptures. Significantly fewer releases are caused by unauthorized activity, natural events, and fires.

In Conclusion

The purpose of this newsletter is to assist bioethanol manufacturers in understanding the seriousness of the hazards and their potential consequences. Many of the biofuel management teams are from industries other than chemical or refinery, therefore they may lack the necessary competence to recognize hazardous chemical risks. Our team is fluent in process safety and can help you comply with regulatory standards, both in the U.S. and internationally.

References

[1] National Fire Protection Association NFPA 660: "Standard for Combustible Dusts and Particulate Solids".

[2] National Fire Protection Association NFPA 30: “Flammable and Combustible Liquids Code (2024 Rev)”.

Catastrophic Incident Prevention and Proactive Risk Management in the New Biofuels Industry Paper

Hazards in ethanol and other biofuel manufacturing processes can result in catastrophic incidents. Download the Catastrophic Incident Prevention and Proactive Risk Management in the New Biofuels Industry white paper by Judy Perry , CCPSC, for detailed guidance on preventative measures and recommended design practices to ensure adequate safeguards are incorporated into a bioethanol manufacturing facility.

To download this white paper, visit our website > https://bit.ly/3XdMzjk

Tools You Need to Conduct a Quality Hazard Analysis

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PStv? Speakers Showcase - Preventing Hidden Risks in Construction & BESS Using PHA Techniques

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Combustible Dust Management

Managing hazards associated with handling combustible dusts requires an understanding of dust characteristics coupled with a thorough knowledge of evolving combustible dust management standards and practices. ioKinetic can help:

Characterize Your Dust

The list of available dust characterization tests is extensive. Before you invest time and money, let our consultants help you define which tests are relevant to your application.

Conduct Process Hazard Analysis Studies

Analyzing your operations can take many forms. From initial assessments to detailed process hazard analyses (PHAs), our consultants can help you come into compliance with the requirements of current codes and standards from OSHA, NFPA, ASTM, etc.

Perform On-Site Assessments

Regulatory compliance is important for upholding the integrity of operations and protecting human safety. ioKinetic can help you put in place preventive or corrective measures based on facts rather than speculation with an on-site assessment.

Size Dust Deflagration Vents

ioKinetic has the capability to size dust deflagration vents using both the shortcut methods in NFPA 68 and dynamic modeling for those systems outside the parameters of NFPA 68.

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