A huge explosion is heard. All plant workers go on red alert. It’s difficult to access the combustion equipment as steam and heat causes them to become disoriented. They call the fire service and the ambulance, provide first aid, and try to limit the damage as best they can. But what exactly happened?
Boiler Risks and Boiler Protection
What caused the chaos in this plant was a boiler explosion. Companies often use burners and boilers to produce electricity, heat, or hot water. With media such as pressure, water, air and fuels, energy is generated in their inside here – but not without risk. In the worst-case scenario, a small leak or overpressure in the boiler is sufficient to trigger an explosion. To ensure safe handling of these systems, it is important that most dangerous areas are permanently monitored, which can be achieved by using boiler protection systems with integrated safety functions. These, however, are often outdated and do not correspond to the current state-of-the-art, thus making monitoring extremely difficult as the responsible personnel cannot be sure what is still protected and where a threat is likely to emerge.
Burners Risks and Burner Protection
Burners, in turn, convert chemical energy into thermal energy. They use fossil fuels such as hydrocarbons (gas or oil) or hydrogen to generate heat. A reaction with oxygen changes the chemical composition of carbon or hydrogen – a process called combustion – and releases thermal energy. The resulting hot exhaust gases transmit their heat to heat exchangers and are cooled down to a point where the exhaust gases have to be discharged through a flue gas fan. This process serves to maintain an optimal efficiency of the combustion appliance.
In our hypothetical accident, the failure of a large steam consumer caused excessive pressure in the boiler. The safety device then shut down the burners – the two mechanical overpressure valves on the boiler tripped and fogged the surrounding plant equipment. However, because the plant operators fully and properly implemented the emergency procedures, including the instructions from fire and emergency services, major damage could be avoided.
Are the Dangers Merely a Product of Our Imagination?
The process seems to be running smoothly – but still, these operators are handling high pressure, intense heat, and explosive gas. These factors in combination could spell danger for the plant itself, as well as people and the environment.
Plants with inadequate safety measures can be a major source of danger as they can emit flames, flue gases or hot steam. Referring to burners, in particular, the air-fuel ratio is a critical factor. If the two substances aren’t balanced, harmful exhaust gases can be released, or an explosion can occur. If temperatures or pressure inside the boiler are too high, the energy released can no longer be controlled. That is also why the boiler from the earlier example caused a hazardous situation with the potential to injure several people and destroy the plant.
And as digitization increases, targeted cyberattacks on process plants are becoming more frequent. Hackers seek to cause economic harm or endanger human lives.
In many cases, gaps in security also lead to halted production. Companies want to avoid this as best they can, as even a single day of downtime can cost a company millions. For this reason, they invest in appropriate safety systems that can reduce the risks to a minimum.
Safety Through Control
To reduce the risk of danger, the process values must usually be maintained within the material-specific limits. This is because steels used in burners and boilers have varying properties which highly influence permissible temperature and pressure ranges.
Compliance with safety-relevant limits ensures a safe balance of the materials used, taking into account the required temperatures, pressures and speeds – for example, boiler water level specifications are set to prevent the total loss of the boiler and the breakdown of the turbine. High-performance safety systems don’t just control and safeguard the burners and boilers, they stabilize and regulate the steam generation and combustion process. The control function intervenes before the safety-relevant equipment is switched off. With little financial effort, companies can prevent unnecessary downtime and risks. The bottom line is that they reduce system failures without sacrificing safety.
Safety checks and actions as well as periodic maintenance work performed by safety experts are additional measures which can help to detect vulnerabilities and malfunctions at early stages – and thus respond accordingly. These experienced specialists can also ensure that safety standards are met at all times, saving plant operators more time to concentrate on their daily duties.
A failsafe option is to comply with functional safety, according to international safety standards. A safety lifecycle, consisting of seven predefined safety phases, ensures the safety of process plants, a process that only involves qualified staff documenting and verifying every single step.
If their instructions are followed, handling burners and boilers can be safer than ever before – and hopefully, in the long run, boiler explosions will be a near impossibility.