Biodiesel Plant Safety

Safety issues have been a chief concern for the biodiesel industry, as evidenced by a long list of fires and explosions. The following is an assessment of what improvements are necessary to make commercial biodiesel processing safer.
By Pete Moss | February 23, 2010
Questions abound as to why biodiesel plants have a much poorer safety record than other chemical and petrochemical operations, and what steps can be taken to address this issue before the industry suffers irreversible damage. Improvements can and should be made to determine new benchmarks for industry participants.

The first step in assuring biodiesel safety is implementing a process safety management (PSM) program, which includes a hazardous operations review. The code of federal regulations 29 under CFR 1910.119 mandates a PSM program if more than 10,000 pounds (1,517 gallons) of methanol is present in a production facility, and all but the smallest of plants have more than this. But even the smallest plants should implement program mandates for employees and protection of investments, and to be responsible neighbors.

The PSM program is not a document that can be copied from one site and applied to another. Each phase of the operation is evaluated for potential hazards and problems that could be encountered during normal operation, start up, shut down, and stand by or down time. It must be prepared by a competent, experienced company or individual, and the facility's operations staff. Adequate time should be allowed for a review of each operation and piece of equipment in detail.

As part of the PSM program, the piping and instrument diagrams should be complete and ready for review. A set should always be available at all locations for operating personnel. These drawings can be the outline for the review of each phase of the operation. The PSM program also requires detailed operating instructions for the plant so someone unfamiliar with the plant could read and understand the steps for safe, reliable, normal operation, start up, shut down, and maintaining an idle plant. It also describes formal safety training that must take place before operations begin. The training includes OSHA requirements, hot work permit requirements, enclosed space entry permits, required personnel safety protection equipment, and more.

Each step in the process is analyzed by the experienced program provider, and the operations management staff. The first step in the review is to assure that each piece of equipment is safe during normal operation: the electrical classification, instrumentation and mechanical installation. The next two steps are a similar review for start up and shut down. Following this is a similar review for the plant being idle with or without process fluids present, then review of procedures for mechanical and electrical work in the plant during operation and down time.

The review would also include any special precautions for handling hazardous materials, each of which must be reviewed separately. Special attention must be given to methanol during normal containment in the operating and downed plant. The hazards of methanol for equipment failure, such as a pump seal failure, must be assessed.

The methanol-based catalyst requires review in the same manner. The handling of acids and caustics should also be reviewed thoroughly, and should include recommended personal protection equipment required for every instance that acid or caustic may be encountered. In each stage of the review, recommendations should be made for steps to take in case of failure in one of the systems.


Common Problems

Most of the common causes of biodiesel plant problems stem from failure to adhere to good manufacturing practices for this type of chemical plant.

Methanol The largest safety hazards in biodiesel plants are methanol and catalyst, which contains 75 to 80 percent methanol. Methanol is highly flammable and vapors are explosive over a wide range of concentrations, and since they are heavier than air, vapors accumulate in low areas of the plant. Indoor production units should be well ventilated according to the NFPA code. Many insurance companies and local fire departments require sprinklers in these areas because the hazard is so great.
The hazard classification should adhere to the National Electric Code so no spark-generating electrical components are allowed in the area. The equipment selection and installation should assure that components have the highest reliability to reduce mechanical failure.

Frequent causes of methanol escaping into the operating area are pump seal failures, hose failures, instrumentation connection failures and similar incidents. Personnel should be trained to be observant for any mechanical abnormalities so remedial action can be taken immediately.

Another potential problem is spill containment, which should not only comply with storm water legislation but also control hazardous collections of flammable materials in unprotected areas. Many plants follow the guidelines for most areas but fail for hose connections that can create methanol spills.

Equipment selection and design Once a plant is operating each piece of equipment should be evaluated, and all safety precautions reviewed, to minimize chance for leaks, failure and design conditions. Temperature and pressure should be well within operational limits. Question the vendor to assure correct application in a biodiesel plant.

The design for equipment installation and relevant support systems must also be thoroughly reviewed. Pressure relief instrumentation should be selected based on upset conditions versus normal plant operations alone. Relief should be provided for overheating, over pressure, over temperature, and even upset conditions such as fire.

If fire occurs, precautionary measures should be prepared for the tank, heat exchanger, pump and other affected areas. Control instrumentation is typically designed for operating within normal limits and appropriate actions should be taken when limits are exceeded. These systems should include action and/or operations notification for processes going outside normal limits, whether it is a slow or rapid upset.

Each piece of equipment and area should be reviewed to assure correct electrical classification is met, including proper grounding. Access for maintenance is also critical for safety.

Operator training In start up operations, especially in smaller installations, operator training is often viewed as unnecessary costs to be minimized and shortened as much as possible. For a plant to operate safely, operators need thorough understanding of the mechanics and chemical reactions associated with the facility. At minimum, training should include how to start up, operate and shut down the plant.

Each piece of equipment and plant area should have an adequate training protocol so every employee has a basic understanding of each item and how it relates to other plant operations, and control, field and maintenance operators should all be included.

Understanding the basics of the entire process is also necessary for every employee. This knowledge will allow the operator to understand why issues are arising and how to respond to root problems versus treating specific symptoms. Upset conditions can cause very severe problems if the operator doesn't understand the root problem.

Everyone in the plant not only needs access to Material Data Safety Sheet information, but needs to know each material used. They need to know the proper personal safety equipment required in all areas of the plant and personal safety equipment required in special areas, or when handling certain materials. When unloading a truck of catalyst, caustic or sulfuric acid, personal safety equipment is required-not recommended.

Each operator requires instruction on how to respond to abnormal operations such as spills, tank overflows, electrical power outages, sudden operational disruptions, natural disasters and fires. The quick and accurate response to problems can sometimes prevent personal injury or death and loss of property.

Mandatory training includes the items required by the federal government in all similar industries. The biodiesel industry, which is young and relatively immature, needs to step up its efforts to improve the efficacy of its safety and training programs to save lives, money and preserve the industry's reputation.

A Brief, Recent History of Safety-related Biodiesel Plant Issues
A few of the adverse events as reported in media sources will be listed as examples of problems that can occur, most of which could be avoided with proper preparation.

American Biofuels, Bakersfield, Calif., 02/17/2006
During a methanol transfer, a small spill occurred. The methanol was ignited and the fire spread into the process building. Apparently, the spill was not contained. Likewise, an ignition source was present around a flammable liquid in an upset condition. A PSM should have identified these two issues so that the spill would be contained and the area would be electrically classified so that no ignition sources should be present. This emphasizes the absolute need for the PSM Program for any size biodiesel plant.

Sun Break Biofuels, Canby, Ore., 06/23/2006
A major fire resulted when a small fire melted plastic biodiesel storage tanks. Even though the cause of the initial fire was not listed, the resulting major damage could have been prevented with a PSM Program. The same analysis is that the area should have been electrically classified so that no ignition sources should be present. The area should have containment. Storing biodiesel in plastic tanks is not good manufacturing practice.

Blue Sky Biodiesel, New Plymouth, Idaho, 07/07/2006
A small fire occurred when a worker was installing a vent tube in an existing tank.

Agri Biofuels Dayton, Texas, 07/14/2007
A fire resulted from a methanol spill.

Better Biodiesel Spanish Fork, Utah, 7/25/2007
A small fire occurred when there was a mechanical malfunction in a methanol transfer line to the reactor section.

Farmers & Truckers Biodiesel Augusta, Ga., 8/21/2007
A worker was welding a flow meter on the top of a tank and was killed when an explosion occurred.

Foothills Biodiesel Lenoir, N.C., 8/25/2007
Feedstock tanks in the tank farm were destroyed by fire two days after the plant was shut down. The tanks were destroyed. Since the plant was unoccupied, no one was hurt.

American Ag Fuels Defiance, Ohio, 1/3/2008
An explosion occurred when workers left a manhole cover off a glycerin storage tank. A spark ignited methanol vapors.

Green Light Biofuels Princess Ann, Md., 5/18/2008
A hot work explosion occurred when a methane line was being added to the plant. A gas line was hit and the resulting explosion killed one worker and injured a second worker.

Biofuels of Tennessee Decaturville, Tenn., 8/15/2008
A fire occurred in the plant after it had been idle for four months. No cause was determined. The company representative stated that nothing was left but smoldering metal.

All American Biodiesel York, N.D., 8/27/2008
One of four processing buildings and the processing equipment was destroyed by fire. No other details were listed.

Gadsten Fleet Management Facilities Gadsten, Ala., 9/18/2008
A faulty heating element on the City of Gadsten's biodiesel equipment likely caused the top of the tank to blow off (over pressure due to inadequate relief).

Nova Biosource Fuels, Inc. Clinton, Iowa, 9/30/2008
A small fire in the primary biodiesel recovery column was quickly extinguished by the local fire department. The probable cause was a build-up of methanol vapors in the column during a ventilation process required as part of the maintenance activity. No injuries were reported for plant personnel. One fireman received minor steam burns.

GreenHunter Biofuels Houston, Texas, 2/9/2009
A mechanical seal on a circulation pump associated with a process heating unit failed. The resulting excessive heat created caused the fire.

Minnesota Soy Bean Processors Brewster, Minn., 5/24/2009
A fire and explosion on a Saturday night at10 PM resulted in several tanks being on fire.

Midwest Biorenewables Toledo, Ohio, 6/15/2009
A faulty safety valve was blamed for a fire which destroyed one of two production lines. The vacuum control valve imploded, igniting biodiesel.

Columbus Foods Company Chicago, Ill., 7/19/2009
Two workers were seriously injured in the biodiesel plant while mixing glycerin and sulfuric acid.

New Eden Energy St Cloud Fla., 9/24/2009
Multiple chemical vessels exploded. At least one building was destroyed and several tanks. The cause has not been determined but one employee said lighting might have started the blaze and multiple explosions.

Xenerga Biodiesel Savannah, Ga., 10/14/2009
One injury resulted from an explosion in a reactor used to store biodiesel.

Imperium Renewables Hoquiam, Wash., 12/2/2009
An explosion occurred in a 10,000 gallon glycerin tank as a result of over pressurization. The tank reportedly split open.

Kenneth "Pete" Moss is the managing partner and owner of renewable energy consulting firm Frazier, Barnes & Associates LLC. Reach him at pete@fba.com.
 
 
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