Food Grade Steam

Once you boil water for 'x' minutes it clean enough to drink, I wonder why steam would be unacceptable?

Is the water contaminated when you started?

Start with food grade water

And use food grade boiling equipment

Many years ago, when ice plants were powered by coal-fired steam engines, "distilled" water from the engine exhaust was often used to produce an acceptable product.

"The distilling plant comprises a steam separator, steam condenser, skimmer, reboiler, and flat cooler. The steam separator is connected to the exhaust pipe from the steam engine. All impurities, such as grease, etc. carried by the exhaust steam, are removed, and then the vapors are passed through a steam condenser, over which the waste water from the gas condenser is allowed to flow. After leaving the steam condenser the condensed water passes through a skimmer where most of the impurities are removed. The condensed, distilled water contains air and sometimes other volatile substances, possessing more or less objectionable odor. To free it from this, the water is subjected to a vigorous re-boiling in a separate tank. The distilled and re-boiled water is then passed through a flat cooler, over which the cold water passes, and its temperture reduced."

As a still further means of purification, charcoal filters are used..."

This method of obtaining food-grade ice from non-food-grade steam was outlined in Johnson's Handy Manual, 14th Edition, published in 1928. Although it might produce a product acceptable to consumers even eighty years later, it probably wouldn't satisfy modern health codes.

You should contact your State and local health departments for recommendations. Some of them are amazingly helpful.

what you would need is what is call a regeneration steam heat exchanger. it takes the steam that is produced by your boiler(which is "dirty") and runs it through a heat exchanger with filtered water feeding it and filtered water is turned into steam. the problem with it is that you have a lose in the conversion. there is other way to produce "clean" steam. you can install a separate boiler just for your process. you have to size it correctly. BTU, LBS/hr needed and temperature need. Temp and pressure are in direct coloration of each other. 10 psi of steam is about 245 F.

Food grade steam, in the United States is referred to as Culinary Grade steam. The quality of culinary grade steam is called out in 3-A Accepted Practices 609-01.

The guideline requires that plant steam be run through a filter that can remove particulate down to at least 2 micron absolute. All of the pipe, valves & fittings downstream of the filter need to be stainless steel.

If you are in the UK, their standards are higher. You are only allowed to use chemical free steam (sometimes called clean steam).

Chemical free steam is created by using a steam-to-steam generator. Plant steam enters on one end, Deionized or Reverse Osmosis water is put in on the other side, and the plant steam boils the higher grade, chemical free water, thus creating clean steam. The clean steam (like filtered steam) needs to be distributed in an all stainless steel system.

The following link shows typical hook-ups for both filtered and clean steam generation:

http://www.spiraxsarco.com/us/applications/industries/hospitals/applications.asp#app5

The most important issue for you is to determine what the guidelines are for your country and strictly adhere to them.

Good luck!

what we can do for oil refineries?

Boil the speculators and politicians.

5 for off topic

Vipin,

You have to use a deionized water instead of normal boiler feed water.

doing these, all the surface that passes the deionized water shall be of SS316 material to avoid contamination from steel at all. pipinf system and other ancillaries shall be ss316 as food grade approved.

There is a steam boiler that call it a steam-Generator. The heating medium is a normal Steam from Fire Tube Boiler (as you mentioned) passing through the SS coil inside the pressure vessel with SS316 material. from the vessel itself you have to feed the deionized water to create a steam. and that will be a pure steam.

In most cases, this pure steam used in the hospital and even in the food manufacturing facility. You should have to understand what are the quality control requirements. You should also understand what the worst scenario of contamination during lab testing of the product so that you root cause the problem and reslove it.

regards,

jojie_oak