Re: Frequency Of Dust Explosions
Here is a great site on dust explosions and hazards (prevention, protection, facts, etc)
www.cvtechnology.com
Specifically, these pages offered a detailed write up on dust explosion and explosion prevention.
www.cvtechnology.com/txtDustExplosion.htm
www.cvtechnology.com/txtExplosionProtection.htm
I hope that helps! ■
Dust Explosions
Greetings from the soon to be frozen "Eastern Wilderness" @1140 feet abovew mean sea level.
As my economics professor has said every thing has its opportunity cost. The problem you have is a large one and unfortunately not unique in its self.
Over hre we have a saying - the Ben Franklin closing argument.
This is where you add up all the pluses and minuses and use the resulting answer-if this is still not enough you could contact Lloyds insurers, AIG and many others that deal with physical plant and stattistics regarding explosion hazards and their prevention ■
Explosion Frequency - Types Of Equipment
Dear Sir,
I also am interested in statistics about frequency of explosions and types of equipment effected, but have not come across them.
An economical solution, a measure of "last resort" against the destructive effects of dust explosions, are HOERBIGER explosion relief valves. They are not "one time products" (like bursting panels), require little maintenance and are capable of flame extinction (ATEX certificate for dust and gass classes 1 and 2). Indoor installation is feasible. They can be fitted to elevators, dust collectors, silos, mills, ducts etc.
Please see www.hoerbiger-kt.com and follow the path of products down to explosion relief valves.
Please contact me for further information.
regards - Dieter M Blaufelder
dieter.blaufelder@hoerbiger.com ■
Explosion Frequency
Dear Sir,
after discussing this issue with a friend, he came up with the following which you may find useful:
Geoff Lunn: Dust Explosion Prevention and Protection, Part 1 - Venting
Publishers: Institution of Chemical Engineers, Rugby
2nd edition, 1992
see page 2 which uses stats from HSE. sorted by industry and by equipment
next:
Explosion Safety and Risk Control, Technology Institute K VIV, March 1994, Ghent
next:
UK Fires and Explosions 1979 - 1984
EuropEx Newsletter, Edition 8, October 1988
European Information Centre for Explosion Protection
Good luck and regards - D ■
Frequency Of Dust Explosions
Try "Safetynet", a European network on process safety.
Michael Reid. ■
Frequency Of Dust Explosions...
Dear friend
Your question on dust exp statistics is a very fair question. Unfortunately I don’t know any source providing this propriety information… You may have to do some data mining. One place I can suggest is the web site of Chemical Safety Board (CSB) of USA: www.csb.gov. This is an excellent information source and they do have an incidents database, covering all kinds of industrial accidents in the US (fires, explosions, chemical spills, leaks, etc…).
With regards to inerting or explosion protection. It is always a good practice to have multiple layers of protection on your systems. Explosion Protection or Inerting is just one of the “must” ones depending on the material & process. As you are well aware they both have pros & cons with the implementation. One alternative I can suggest is, to look at the overall costs & benefits of implementing an explosion protection system along with a condition monitoring system. Condition Monitoring doesn’t necessarily mean a maintenance system, but a network of low cost sensors placed on locations that are most prone to risks (potential ignition sources are present, or materials are in their flammable / combustible ranges) along with a suitable data logging & alarming system. And of course, as one of the fundamental steps, good operator guidelines on the safe operation of your systems. The condition monitoring system will continuously monitor process for any deviations from the normal operations, and will give an alarm to process engineer. This information can also be used for analyzing the efficiency of operations...The protection system will work at the background as the guard to protect against any potential failure conditions. If you look into the monitoring systems, you will be surprised to find very cost prohibitive systems that are easy to install, use & maintain. I know this does not directly answer your question, but may provide you an alternative perspective... ■
Frequency Of Dust Explosions
Apparently, accident statistics can show which parts of the process are most susceptible to an explosion, with further study on the main causes: aging of the equipment, poor maintenance, lack of technical training for operators, etc.
Therefore, wanting to use explosion statistics as a support to decide the protection system, based on economic values, seems to be wrong.
Each type of plant has its environmental and operational characteristics, so that a specific analysis on a case-by-case basis should point out the solution with the best cost-benefit ratio, including considering the financial availability of the owner. ■
Frequency of Dust Explosions
Does anyone know of a source of reference data on the frequency of dust explosions on equipment protected by explosion venting ?
I know that there are many variables, the MIE of the powder, the type of equipment being protected ( the frequency on a grinding mill will clearly be much greater than on a silo for example). the size of the equipment, etc.
The "problem" is as follows, if I have a system protected by inerting, I am preventing an explosion occuring, I can make it safe but there is a cost in supplying the inert gas system and ongoing cost in use of inert gas.
If I have a system protected by venting then I am accepting that an explosion may occur, I can make it safe but there is a cost in explosion panels, maintenance of panels, etc.
With this second option however there is another issue, the cost and implications of an explosion event. If an explosion occurred, there would be a cost of lost production, loss of product (what would be left in the vessel would probably be out of specification) as well as the "softer" issues such as environmental effects, noise, perception of danger by neighbours, claims from neighbours for cleaning up any residue which may fall on their property, general PR issues, etc.
If inert gas has to be imported for inerting, the economics are fairly clear unless the dust is toxic or very sensitive, venting is probably the most sensible answer.
However a number of plants in the chemical industry produce low oxygen gas after buring air in the reaction and this gas is routinely used to make inerting as the basis of safety. It is often ignored that there is a cost involved in the use of this gas as well.
In order to make a quantative assessment of the pro's and con's of each option, it is necessary to be able to put some figure on the likely frequency of a dust explosion when using vents. Is it once every 10 years, 100 years, 1,000 years or 10,000 years? Is that per plant or per silo / per conveying system / etc.
Any thoughts or comments ?................ and any idea where to get hard data to back them up? ■