Emission monitoring system and method

• US 20020059033A1
• Filed: 04/30/2001
• Published: 05/16/2002
• Est. Priority Date: 04/28/2000
• Status: Active Grant

• Current Assignee: PPL Energy Supply LLC (Talen Energy Corporation)
• Original Assignee: PPL Electric Utilities Corporation (PPL Corporation)
• Inventors: Romero, Carlos E., Batug, James P., Moyer, Noel, Yilmaz, Ali, Levy, Edward K.
• Granted Patent: US 6,701,255 B2
• Time in Patent Office: Days
• US Class Current: 702/24
• CPC Class Codes: G01N 1/2258 in a stack or chimney
• CPC Class Codes: G01N 2001/2264 with dilution
• CPC Class Codes: G01N 33/0018 by diluting a gas
• CPC Class Codes: G01N 33/0037 for NOx
• CPC Class Codes: G01N 33/004 for CO, CO2
• CPC Class Codes: G01N 33/0042 for SO2, SO3
• CPC Class Codes: Y02A 50/20 Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters

Abstract

An emission measuring system and method provide an accurate, real-time calculation of a particular material emitted from an emission source. Specifically, a CEM system installed in an industrial stack can include a dilution probe located in the stack and a data analyzer that records and analyzes characteristic data of the materials sampled by the dilution probe. A dilution ratio is used to correct for the addition of dilution gas into the stack gas sample to determine the concentration of a particular material that is being emitted from the stack. The dilution ratio is based on a molar flow rate, which can be determined by using specific algorithms and measurements.

Claims

1. An emission measuring device, comprising:

an analyzer that is capable of measuring a characteristic of an emitted material that is emitted from an emission source; and

means connected to the analyzer for calculating an amount of a particular material contained in the emitted material by using a mass flow rate value.

2. The emission measuring device of claim 1, wherein the amount of a material that is calculated is a concentration of material.

3. The emission measuring device of claim 1, wherein the mass flow rate value is based on a molar flow rate value.

4. The emission measuring device of claim 1, further comprising:

a dilution probe that receives emitted material and dilution gas which forms a mixture known as diluted sample gas, and that is in communication with the analyzer, said mass flow rate value being a value corresponding to one of a mass flow rate of dilution gas, a mass flow rate of sample gas, and a mass flow rate of emitted material.

5. The emission measuring device of claim 4, wherein the dilution probe is located in one of a stack and a duct.

6. The emission measuring device of claim 1, wherein the means for calculating the amount of a particular material calculates by using a dilution ratio based on the mass flow rate value.

7. The emission measuring device of claim 6, further comprising:

a dilution probe connected to said means for calculating and configured to receive a sample gas that includes the emitted material and a dilution gas, wherein the dilution ratio is determined as follows;

$D=1+\frac{565.338<br><br>\text{\hspace{1em}<br><br>}<br><br>F_{\mathrm{da}}<br><br>\sqrt{T_{\mathrm{stack}}}<br><br>\sqrt{M}<br><br>\left[1+y<br><br>\left(T_{\mathrm{stack}}-530\right)\right]}{{P_{\mathrm{absolute}}<br><br>\left[1+\mathrm{\beta <br><br>}<br><br>\left(T_{\mathrm{stack}}-530\right)\right]}^2}$

where D is the dilution ratio, F_da is a mass flow rate of the dilution gas, T_stack is an emission source temperature, M is a molecular weight of the emitted material, y is a constant, P_absolute is total emission source pressure, and β

is a thermal expansion coefficient of orifice material located on the dilution probe.

8. The emission measuring device of claim 6, wherein the dilution ratio is determined as follows:

D=({dot over (n)}_dil+{dot over (n)}_stack)/{dot over (n)}_stack

where D is the dilution ratio, {dot over (n)}_dil is a molar flow rate of dilution gas, and {dot over (n)} stack is a molar flow rate of emitted material.

9. The emission measuring device of claim 6, wherein the dilution ratio is determined as follows:

D=1+[(m_d/m_s)*(M_s/M_d)]

where D is the dilution ratio, m_d is a mass flow rate of dilution gas, m_s is a mass flow rate of emitted material, M_d is a molecular weight for dilution gas, and M_s is a molecular weight for emitted material.

10. The emission measuring device of claim 1, further comprising:

a dilution probe connected to said means for calculating, wherein the emitted material is combined with a dilution gas to form a sample gas, and the means for calculating the amount of a particular material calculates by using a mass flow rate of sample gas determined as follows;

$m_s=\mathrm{\alpha <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>C_d<br><br>\frac{P_{\mathrm{absolute}}<br><br>\sqrt{M}<br><br>{A_o<br><br>\left[1+\mathrm{\beta <br><br>}<br><br>\left(T_{\mathrm{stack}}-530\right)\right]}^2}{\sqrt{T_{\mathrm{stack}}}}$

where m_s is a mass flow rate of the sample gas, C_d is a constant, C_d is a discharge coefficient, P_absolute is a total emission source pressure, M is a molecular weight of the sample gas, β

is a thermal expansion coefficient of an orifice material of the dilution probe, A_o is a throat area of a critical orifice of the dilution probe, and T_stack s an emission source temperature.

11. The emission measuring device of claim 10, wherein T_stack is the critical orifice upstream stagnation temperature.

12. The emission measuring device of claim 10, wherein P_absolute is the critical orifice upstream stagnation pressure.

13. The emission measuring device of claim 1, wherein the means for calculating includes a data analyzer that is adapted for use with an existing plant data handling and acquisition system.

14. The emission measuring device of claim 13, wherein the data analyzer includes an output line that can be connected to the existing plant data handling and acquisition system to transfer dilution ratio data.

16. The system for use with an emission source of claim 15, wherein the mass flow rate value includes a mass flow rate of dilution gas measured by one of a transmitter and an analyzer.

17. The system for use with an emission source of claim 16, wherein the transmitter is a flow meter.

18. The system for use with an emission source of claim 15, wherein the mass flow rate value includes a mass flow rate of a sample gas.

19. The system for use with an emission source of claim 18, further comprising:

a dilution probe connected to said means for calculating and configured to receive a sample gas that includes said emitted material and a dilution gas, wherein said mass flow rate of sample gas is calculated as follows;

$m_s=\mathrm{\alpha <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>C_d<br><br>\frac{P_{\mathrm{absolute}}<br><br>\sqrt{M}<br><br>{A_o<br><br>\left[1+\mathrm{\beta <br><br>}<br><br>\left(T_{\mathrm{stack}}-530\right)\right]}^2}{\sqrt{T_{\mathrm{stack}}}}$

where m_s is a mass flow rate of sample gas, α

is a constant, C_d is a discharge coefficient, P_absolute is total emission source pressure, M is a molecular weight of the sample gas, β

is a thermal expansion coefficient of an orifice material of the dilution probe, A_o is a throat area of a critical orifice of the dilution probe, and T_stack is an emission source temperature.

20. The system for use with an emission source of claim 15, wherein the means for calculating an amount of the particular material emitted from the emission source calculates a concentration of the particular material using a dilution ratio.

21. The system for use with an emission source of claim 20, further comprising:

a dilution probe that has an orifice for receiving a sample gas which includes the particular material combined with a dilution gas, wherein the dilution ratio is calculated as follows;

$D=1+\frac{565.338<br><br>\text{\hspace{1em}<br><br>}<br><br>F_{\mathrm{da}}<br><br>\sqrt{T_{\mathrm{stack}}}<br><br>\sqrt{M}<br><br>\left[1+y<br><br>\left(T_{\mathrm{stack}}-530\right)\right]}{{P_{\mathrm{absolute}}<br><br>\left[1+\mathrm{\beta <br><br>}<br><br>\left(T_{\mathrm{stack}}-530\right)\right]}^2}$

where D is the dilution ratio, F_da is a mass flow rate of dilution gas, T_stack is an emission source temperature, M is a molecular weight of the sample gas, y is a constant, P_absolute is total emission source pressure, and β

is a thermal expansion coefficient of an orifice material of the dilution probe.

22. The system for use with an emission source of claim 20, wherein the dilution ratio is calculated as follows:

D=({dot over (n)}_dil+{dot over (n)}_stack)/{dot over (n)}_stack

where D is the dilution ratio, {dot over (n)}_dil is a molar flow rate of dilution gas, and {dot over (n)}_stack is a molar flow rate of emission gas.

23. The system for use with an emission source of claim 20, wherein the dilution ratio is determined using a molar flow rate value.

24. The system for use with an emission source of claim 20, further comprising:

a dilution probe connected to an analyzer, the analyzer connected in communication with the means for calculating a total amount of a particular material.

25. The system for use with an emission source of claim 15, wherein the means for calculating includes a data analyzer that is adapted for use with an existing plant data handling and acquisition system.

26. The system for use with an emission source of claim 25, wherein the data analyzer includes an output line that can be connected to an existing plant data handling and acquisition system to transfer dilution ratio data.

28. The method of claim 27, wherein said emission gas is a calibration reference gas used for verifying the accuracy of the method.

29. The method of claim 27, further comprising:

determining a molecular weight for the sampled emission gas.

30. The method of claim 27, wherein the step of determining a mass flow rate includes determining a molar flow rate of the emission gas.

31. The method of claim 27, wherein the step of sensing includes using a dilution probe configured to receive a sample gas that includes the emission gas and a dilution gas.

32. The method of claim 31, wherein the step of calculating a dilution ratio includes calculating the dilution ratio as follows:

33. The method of claim 31, wherein the step of calculating a dilution ratio includes calculating the dilution ratio as follows:

D=({dot over (n)}_dil+{dot over (n)}_stack)/{dot over (n)}_stack

where D is the dilution ratio, {dot over (n)}_dil is a molar flow rate of dilution gas, and {dot over (n)}_stack is a molar flow rate of emission gas.

34. The method of claim 31, wherein said step of determining a mass flow rate includes determining the mass flow rate as follows:

35. The method of claim 27, wherein the characteristic of the emission gas is a concentration.

36. The method of claim 27, further comprising the step of:

sending a signal corresponding to the value of the calculated dilution ratio to a data acquisition and handling system.

37. The method of claim 27, wherein the step of calculating includes providing a data analyzer to perform the calculation of the dilution ratio, the data analyzer being capable of retrofitting to an existing data handling and acquisition system at an industrial facility.

38. The method of claim 27, further comprising:

determining a mass flow rate of dilution gas; and

determining emission and dilution gas molecular weights;

wherein the step of calculating a dilution ratio is also based on determined mass flow rate value of the dilution gas, and determined emission and dilution gas molecular weights.

40. The emission measuring device of claim 39, wherein the data system calculates a concentration of the particular material using a dilution ratio, and the dilution ratio is calculated as follows:

D=({dot over (n)}_dil+{dot over (n)}_stack)/{dot over (n)}_stack

where D is the dilution ratio, {dot over (n)}_dil is a molar flow rate of dilution gas, and {dot over (n)}_stack is a molar flow rate of emission gas.

15. A system for use with an emission source, comprising:

a data medium for receiving emission data collected from one of an analyzer and a transmitter, the emission data including one of a pressure, a temperature, and an amount of a particular material emitted from the emission source; and

means for calculating an amount of the particular material emitted from the emission source using a mass flow rate value.

27. A method for calculating an amount of a material emitted from a source, comprising the steps of:

sensing an emission gas emitted from the source;

determining a mass flow rate value of the emission gas;

calculating a dilution ratio based on the determined mass flow rate value of the emission gas; and

determining a characteristic of the emission gas using the calculated dilution ratio.

39. An emission measuring device, comprising:

an analyzer that is capable of measuring a characteristic of an emitted material that is emitted from an emission source; and

a data system connected to the analyzer and configured to calculate an amount of a particular material contained in the emitted material by using a molar flow rate value.