Air Pollution Control System Costs Still Rising - Hot Topic Hour September 25, 2008

The cost of air pollution control has risen substantially in the last five years. The challenge of predicting the cost of your next system is increased because of the wide variation in reported costs. In the Hot Topic Hour yesterday on “Air Pollution System Cost Escalation” data on recent experience was analyzed.

Last week Evonik showed cost comparisons between wet lime and limestone which showed that lime was the economical choice for many of the Steag plants. The atypical small cost differential between lime and limestone in Germany along with the lower energy consumption were the main factors.

Published data on the LCRA 1200 MW FGD project showed that while an FGD system for a new plant might cost only $150/kW a retrofit could be $185/kW on average but could be as much as $275/kW.

SCR catalyst prices are around $5,500/m³ with material costs accounting for $2,655. SCR retrofits can range from $120-180/kW. One big variable is the fan requirement. If the existing fan cannot handle the extra pressure drop then the system will cost considerably more. IEA reports SCR retrofit costs at between $61-182/kW. EIA in their 2008 Outlook assumed $108/kW for a retrofit to a 500 MW plant.

The cost of new power plants has risen 130 percent since 2000. If you exclude nuclear the rise is only 80 percent. A major cause of the escalation has been the excess of demand over supply. This in turn is a function of regulations. McIlvaine believes that there will be a huge requirement for scrubbers for installation prior to 2015. HAPS and a new Clean Air Act may contribute but the big driver will be PM_2.5.

The States must be in attainment by 2015 even with an extension. Furthermore eastern states will sue the states to the west of them if they do not think that they can otherwise meet the limits. The reason that it is going to be so tough is that less than ½ ton of SO₂ can make a major impact on the entire national non-attainment region.

SO₂ Calculations for PM_2.5

(15 x 10^-9 kg/m³) X (9,826 X 10⁹ m²) X 2m X (1 ton/907 kg) = 325 tons  

30% Contribution by Sulfates: 0.30 X 325 tons = 97.5 tons

SO₂ Contribution:  97.5 tons [64/132] = 47.3 tons across total U.S. 

Total permissible SO₂ in 1% Non-Attainment Area: 47.3 tons X 0.01 = 0.47 tons

The above calculations are based on a breathing area of two meters high and represent the quantities in the air at a point in time. There are 907 billion micrograms in just one ton of SO₂. So this is the reason it will be so tough for any state to meet its limits. This calculation does not take into account residence time, dispersion, or many other factors that would impact the real impact of any one ton of SO₂, but it establishes the significance of just a small quantity.

The price of Appalachian coal has doubled in just the past year. Experts are advising utilities to consider the cost impacts before choosing an air pollution system which limits them to just one fuel.

Illinois basin high chlorine coals have been neglected and consequently could be obtained at low prices. McIlvaine contends that power plants can make 30 percent hydrochloric acid and capture 99 percent of the mercury at the same time. Here is the schematic.

A small pre-scrubber precedes the conventional SO₂ scrubber. Water is recirculated until a 30 percent hydrochloric acid solution is reached. Acid is then bled to a treatment system which separates particulate and mercury. Purified 30 percent acid is then a marketable commodity.

By also recycling some acid to the inlet of the SCR it is possible to obtain 99 percent mercury removal. Advantages are:

Ø  Use lower cost coal and PVC waste,

Ø  Capture 99 percent of the mercury,

Ø  Sequester mercury as small quantity,

Ø  Eliminate expensive wastewater treatment,

Ø  Reduce cost of downstream SO₂ scrubber,

Ø  Eliminate mercury in gypsum,

Ø  Significantly reduce levelized costs,

Ø  Reduce rather than increase operational risks and downtime.

There are many HCl pre-scrubbers operating on coal-fired power plants. However, they are not making 30 percent acid. On the other hand, many incinerators and chemical plants are making salable acid using this approach.

The Nuremberg Waste incineration plant has an HCl scrubbing system making and selling 30 percent hydrochloric acid. The plant has a capacity of 204,000 Mg of waste annually.

http://www.aee-vonroll.us/downloads/nuremberg.pdf

AE&E has just started up a system with an HCl scrubber in Austria. The 40 MW Pfaffenau energy-from-waste facility incinerates about 32 tonnes of waste per hour to produce clean and safe energy, disposing of 250,000 tonnes of waste per year in the process. The plant will supply 25,000 households with electricity and a further 60,000 Viennese households with district heating.

This concept of making acid could apply to either large or small plants. The levelized cost will be less than for a conventional FGD system with 70 percent mercury removal. So the benefits are both higher mercury removal and lower cost.

Cost data is listed in the FGD Decision Tree.

FGD Continuing Decision Process For: Cost

Cost Data presented at Air Pollution System Cost Escalation Hot Topic Hour September 25, 2008.

http://www.mcilvainecompany.com/FGD_Decision_Tree/subscriber/Tree/DescriptionTextLinks/cost_data_presented_at_air_pollu.htm