Computer Modeled Resistivity

Using the ultimate coal analysis or a given flue gas analysis and the ash chemical composition, resistivity can be predicted as a function of temperature and environmental conditions. Resistivity is modeled in accordance with EPA Report 600/7-86-010. An example of the model’s output using the data supplied in Table 1, is shown in Figure 3. If one wishes to check the validity of the modeled data, a minimum amount of laboratory data can be acquired for comparison. A reasonable agreement between the modeled data and laboratory data allows one to utilize the modeled information to anticipate resistivity at all temperatures and environmental conditions.

Not really a compound-specific analysis. This algorithm determines the electrical properties of a dust. These properties can be used to determine the effectiveness of:
- Coal-switching studies that evaluate the resistivity of select coals and blends to predict precipitator collection performance;
- Flue gas conditioning used to improve precipitator collection performance; and
- Precipitator design and optimization studies.

A bulk sample (about ten grams) is required for this analysis. Optimally, samples should be pulled from every precipitator hopper and blended into a representative inlet sample. This is simple across the rows, a little more involved from inlet to outlet. The Deutsch-Anderson equation is used along with hopper mapping to blend samples in a row from inlet to outlet fields.
Isokinetic samples can also be used for this analysis. One major inconvenience is the bulk quantity required for the measurements.
Alternatively, resistivity can be modeled from customer-supplied ash mineral analyses and a coal analysis.

Modeled resistivity is well-suited for predictions of how well a candidate coal will work. It can also predict:
- How well sulfuric acid conditioning might help a given situation;
- How well temperature changes might affect a given situation;
- The resistivity of fuel blends.
Below shows the Resistivity modeled as a function of environmental conditions in accordance with procedures in EPA Report 600/7-78-010