Magnesium Hydroxide

[ksprague]

Does anyone have any experience injecting Magnesium Hydroxide into a coal fired furnace to aid in the reduction of slag formations? Seems like it works on humans!

 

[gaterine]

Sorry. I have no direct experience except knowing that it is sold as a fuel additive. Apparently it complexes with vanadium and other low melting poing slag forming materials, providing a high melting point, and hence dry ash.
I have been involved, some years ago now, in some demonstration work on roasting a waste material where sodium content was high. To prevent lumping due to viscous slags we added kaolin with some good results. Kaolin was cheap. We didn't consider refined MgOH. The source of the kaolin was important and I guess this will be true with the coal in your case. The minor impurities, in the kaolin, coal or MgOH, will have a big effect on the success of any additive. Also how/where it is injected.

 

[hrsgguru]

I have not heard of it being added to coal, but it is offered and used in heavy liquid fuels, as gaterine noted, to counter the effects of vanadium slagging in the furnace. Depending on the type of coal burner that your boiler uses, it may provide a similar type of effect.

 

[25362]

The DOE (of USA) has dealt with the subject, and articles to that effect are available on the net. Besides, it has been published that corrosion on the fireside of coal-fired heaters enhanced by contaminants suchs a V, Na, Cl can be mitigated by injection of inhibitors such as Mg(OH)₂.

 

[olivierb]

Magnesium oxide (or hydroxide) is commonly used to reduce corrosion and slagging in fuel oil fired boilers, as it is increasing the pH.

Slagging in coal fired plants often happens when the furnace is too small and thus temperatures around the burners are very high. Here magnesium oxide can successfully be added to the coal flow to reduce this slagging.

Check out

http://www.pentol.com

for additives of this kind!

 

[Charles]

We inject a magnesium and ammonium nitrate product (Polarchem L2K) into a large coal fired power stations in India and also a small CHP plant in the UK. We have other coal fired applications on mainland Europe. In addition to reducing low temperature sulphuric acid corrosion at the back end, we also significantly reduce bird nesting in the super heaters and fireside fouling and corrosion within the boiler.

There are knock-on effects, we will reduce the carbon in ash due to a more complete combustion. This is becoming more relevant as de-NOx regulations kick in and so overfire air has to be increased (as one method of reducing NOx).

Do please look at our website or make contact with us and we would be very happy to answer direct questions.

Apologies for the solicitation!

Charles

http://www.polarchem.com