Heat exchanger is one of the most important equipment for a manufacturing plant. With this equipment, energy transfer can be done and production process runs smoothly.
However, beside its important role, heat exchanger operation and maintenance contain potential safety hazards.
If such safety hazards are not treated properly, unexpected events may happen.
So, it is very important to know heat exchanger safety precautions in order to be safe during operation and maintenance.
What are Heat Exchanger Safety Hazards?
There are several potential heat exchanger safety hazards. Perhaps, it could come during the design phase, operation or maintenance.
Hazards associated with improper heat exchanger operations can be hazardous material leaking, cold metal embrittlement, explosion, fire and a uncontrolled reactions.
Meanwhile, during its maintenance, heat exchanger still can serve safety hazard like explosion, fire and hazardous material exposure.
Heat Exchanger Accident Cases
Learning safety from past accidents is great way to prevent the same event happens at our sites. So, it is very important to learn from any accident case you may can get.
I have searched several heat exchanger accident cases that relate with the topic we are talking about. I urge you to spent your time reading those cases.
By reading those reports, I hope you will have same level of urgency toward heat exchanger safety.
Case-1: Water-cooler heat exchanger in Hydrogen Facility Recycling, Japan, 2014
Case-2: Catastropic Heat Exchanger Failures, Longford Gas Plant, Australia, 1998
Case-3: Heat exchanger ruptures and ammonia release, Good Year Rubber Plant, US, 2008
Heat Exchanger Safety Precautions
Heat exchanger safety hazards could come from improper design, operation or maintenance.
You have to take care on these 3 phases.
Please take care the following heat exchanger safety precautions to prevent accidents:
During the Design
- Make sure you have decided appropriate design condition for the heat exchanger: heat exchanger type, temperature design, pressure design, material compatibility, fluid nature, supports, gas vent, drain and structural design. Inappropriate design will lead to mechanical integrity problems.
- Pay attention to the gasket material. Material selection, gasket type and thickness has to be matched to avoid leakage.
- An abnormal temperature and pressure increases may happen. Design the heat exchanger to withstand in such condition.
- The heat exchanger shall be designed for a safe maintenance environment.
- Over pressure can be avoided by installing a safety relief device.
- A relatively high temperature surface shall be covered by insulation.
- Consider to install alarm system
- Grounding is very important.
- Consider special considerations when designing a heat exchanger suppose for hydrogen peroxide. Such heat exchanger must have an inclined construction to remove gas that usually appears during normal operation.
During Operation
- Tube plugging due to the buildup of foulants. This can cause pressure buildup inside the heat exchanger.
- Beware of tube leaking caused by corrosion. If fluid in hot and cold sides mix, a reaction may occur. A corrosion monitoring, inspection and leak detection are very important.
- If a slurry flow or contaminated liquid flow enters the heat exchanger, erosion may happen and can cause leaking too. Install a filter to separate solid material from the liquid flow.
- Avoid over pressuring the heat exchanger. Do start up and shut down operation smoothly. Follow the SOP.
- Keep out of hot surface that may cause skin burn.
During Maintenance
- Follow LOTO – lock out tag out – procedure when you will maintain a heat exchanger. Make sure all inlet valves are already secured and tag appropriately.
- Release pressure from the heat exchanger. Ensure that the pressure gauge indicates zero bar.
- Drain out hazardous chemical from the heat exchanger.
- Be careful when selecting chemical cleaning material for tube cleaning. Improper selection will cause corrosion and leak.
- If mechanical method is used for cleaning the tube side, take care not to cause tube defect. Mechanical cleaning can cause injury on people too.
- Install new gasket – mainly on the head – carefully to avoid leakage. Improper installation will lead to leakage.
- Hydrostatic test after maintenance job is required. Be careful to do this job safely because a high pressure will be applied.
Recommended Heat Exchanger Books
- Heat Exchanger Design Handbook (Mechanical Engineering 222)
- Compact Heat Exchangers
- A Working Guide to Shell-And-Tube Heat Exchangers
- Fundamentals of Heat Exchanger Design
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