PentoMag - Model 2550 - Coal Slagging (fouling) System

Who needs PentoMag 2550?

If your plant suffers from one of these symptoms, PentoMag 2550 might be a possibility for you to optimize boiler efficiency:

• Significant losses of production
• Heat transfer problems
• Boiler tripping
• Damages at the bottom tubes

On the following pages we try to outline how PentoMag 2550 works and if it is suitable for your plant.

There are 3 main factors that influence slagging in a boiler: Boiler design, coal properties and oxygen level of the combustion. Typically the operator has little influence on all 3 of them. The boiler design cannot be changed, coal properties are subject to the price politics of the enterprise and the choice of operating parameters like excess air is limited due to technical constraints.

PentoMag 2550 somehow eases the pressure on the operator, as it increases the bandwith of operation in the boiler.

There are 2 main working mechanisms:

1. Increase fusion temperature of metals contained in the ash.
   Slags start to accumulate if the ash is in molten form. Once the process starts, it gets worse and worse due to the reduced heat transfer from gas to steam. By increasing the melting point of metal oxides in the ash, the ash remains dry and cannot stick to the walls.
2. Change the structure of deposits.
   PentoMag 2550 changes the amorphous structure of the deposits to a crystalline structure. The advantage is a reduced density and friability of these deposits.

PentoMag 2550 is a combustion additive based on copper and magnesium.

Magnesium oxide has a great influence on fusion temperature of ash independent of the fuel source. Pentol carefully chooses raw material with high activity to keep the dosing rate low and efficiency high. Compared to other active substances, magnesium oxide forms water soluble salts that are easy to remove.

Copper changes the structure of the already existing deposits from an amorphous to a crystalline structure and further increases the effect of the product.

Sophisticated manufacturing and stabilisation of PentoMag 2550 containing up to almost 70% of active substances enables application of very low dosing rates. In most cases 1 liter of PentoMag 2550 is efficient to treat 50 tons of coal. Actual dosing rate is always adjusted according to practical experience during initial dosing period.

To properly evaluate dosing efficiency the cost of treatment per ton of coal is the key indicator rather than additive unit price.

Fully automatic dosing systems: precise, protected and easy to use.

Pentol develops and produces highly reliable dosing equipment specifically for its range of additives. The pictures below show a fully automated dosing skid for small and medium size boilers with a coal flow detector to adjust dosing rate. The product is usually added to the coal before the mills.

A continuous dosing system with very high availability is key to every successful fuel treatment as any interruption of additive supply can lead to a temporary increase of deposits in the boiler.

The dosing system includes an ultrasonic level detector for the coal belt to turn dosing on and off. If signals from the conveyor are available they can be connected to the controller.

The dosing pumps, storage tank and unloading system are installed in a 20 feet container.

Higher Availability

Just like the products of the PentoMag series designed for fuel oil, PentoMag 2550 has a strong influence on availability of the boiler and on maintenance cost. Pentol has clients in Europe, South America and China who rely on this technology to extend the time between scheduled shutdowns planed for cleaning of the boiler.