Case Study

SOUTHWESTERN POWER PLANT TECHNOLOGY DEMONSTRATION – APRIL 2013

Polarchem was involved in an online boiler cleaning demonstration. The demonstration took place at a coal fired power station located in Southwest USA. Application of both our Polarchem G3 and L2K products were used in this demonstration to show the effectiveness it offers in reducing LOI, improving combustion, and removing fouling and slagging from the boiler fireside surfaces. On April 1st, Polarchem’s agent met with the stations operational staff and engineers to discuss our process and identify injection points that could be utilised effectively. Demonstration data collection points and sample collection parameters were defined. Product injection began on April 2nd, and continued through to April 18th.

BOILER SPECIFICATION

UNIT SIZE

130 Mega Watts* – 3×3 wall fired unit.
(*Maximum generating capacity burning coal).

FUEL

Coal (Twenty-mile) – Peabody Energy.
11,200 Btu per pound with low sulfur and ash content.

OPERATING LOAD

Variable load between 60 – 120 Megawatts

PLANT ISSUES

Slagging and fouling of combustion area boiler tubes and upper superheater pendent section. Heavy clinker formations and incomplete combustion at low and mid-range operating loads.

Superheater Pendent – Before Cleaning

Tubes Above Burners – Before Cleaning

Wall Tubes – Before Cleaning

We discovered heavy slagging on tube and fireside surfaces. By simply adjusting the dosage of the concentration, our injected solution was able to easily loosen and remove these heavy foulings.

Superheater Pendent - After Cleaning

Wall Tubes - After Cleaning

Tubes Above Burners – After

The field technician injected two formulations, Polarchem L2K and G3, for a period of 160 hours over 16 days. In the photos above, you can clearly see how the product has cleaned the boiler fireside tube surfaces.

Bottom Ash - Before Injection

After 36 Hours

After 160 Hours

Following the first three days of injection, the bottom ash composition changed from a hard, discolored material to an uniform gray color with very low compressive strength. This is a clear indication of a reduction in unburned carbon.

Bottom Ash Pile – Before Injection

Material Characteristics Change

Bottom Ash Pile – End Result

As a result of poor combustion, dense hard clinkers containing significant iron oxides and encapsulated unburned carbon were formed. As application continued, the composition of the bottom ash changes.

Injection System

Concentrate Feed Tank

Manual Injection Lance

Manual injection systems designed and manufactured by Polarchem were stationed at separate levels. Each system serviced two lances; a total of four lances were active during the demonstration.

Results:

The measured gain in megawatts per ton of coal improved by 2.1%. This efficiency gain calculates to an estimated annual fuel saving of $567,000. We anticipate the long-term potential of more than 4% efficiency gain, which would result in annual fuel savings of over $1,000,000. The total net benefit of the Polarchem technology will be much higher than the 4% efficiency gain when you consider the reduced need for soot blowing, reduced tube failure (reduced shutdowns) and reduced emissions.

Our Recommendations was:

Continue injections to fully clean the boiler.
Inspect overall tube condition during the scheduled October shutdown and resume injections at a reduced maintenance level to keep the tubes clean.

This utility has volunteered to bring personnel to inspect their base‐load plant which has four boilers generating a total of 1,670 megawatts.