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CENE 330 Air Quality Engineering

Homework #6 – Optional Problems

Assigned: December 4, 2016

Due: December 15, 2016

This optional homework provides up to 50 points for replacing a previously, lower-scored

homework assignment.

Instructions

These problems are to be handed in, no later than 7:29 AM, prior to the beginning of the final

examination on December 15th.

Overall your work must be extremely well organized and easy to follow. Work these problems

on gridded Engineering Computations pad paper. This will allow you to better organize your

work, and create plots that are neatly drawn and properly scaled, and tables that have

information properly aligned in rows and columns. Use a straight edge for all straight lines

included in this assignment. You must also make certain that your writing is legible. Print, do

not use scripted or cursive lettering, and use a letter height equal to the height of the

horizontal grid spacing. You will automatically lose 10 points if any one of these requirements

are not followed throughout the entire assignment.

All calculations steps must be shown, or in the case of a graphical solution, must be described

such that your solution approach can be verified. I should not have to assume how you have

approached any calculations or graphical solutions. You will lose points in proportion to the

significance of the missing calculation or explanation, in the case of a graphical solution.

Show all unit expressions, in all calculations and with the presentation of values used or

otherwise reported. Do not used mathematical operations improperly; in particular, do not use

an equal sign between two expressions when they in fact cannot be demonstrated as being

equal. You will lose 1 point for each occurrence of a missing unit expression and improper use

of a mathematical operand.

The use of an incorrect unit expression is an incorrect calculation, and will be scored the same

as any calculation that has been incorrectly setup; the entire point value for that calculation will

be lost.

Errors clearly associated with performing the calculation (for example the wrong value was

likely to have been entered into the calculator), as opposed to setting up the calculation, will be

treated as a minor error and 1 point will be lost for each occurrence.

Incorrect values resulting from either incorrectly setting up a calculation or incorrectly

performing the calculation incorrectly, will be used in subsequent calculations to verify that

setting up and preforming these subsequent calculations is done correctly.

Plots must be properly constructed, which includes the orientation and use of axes, and the

scaling and labeling of axes. You will lose 2 points for each of these occurrences.

Problem 6.1 (7.5 pts.)

Plot the ambient air temperature profile for the following data.

a) For the altitude between 500 feet and 1 000 feet, what is the

lapse rate and is the lapse rate greater or less than the DALR?

b) For the altitude between 1 500 feet and 2 000 feet, what is the

lapse rate and is the lapse rate greater or less than the DALR?

c) What is the stability condition of the between ground level and

500 feet?

d) If air on the ground is heated to 62°F, how high would it rise

under this temperature profile condition (what is its mixing

height)?

Problem 6.2 (10 pts.)

A soil contaminated with 100 mg metals/kg of soil, 50,000 mg S/kg of soil, 1,000 mg F/kg of soil

and 40,000 mg Cl/kg of soil, is to be treated using an incinerator. The incinerator is operated at

a heat load of 63 MM Kilojoules/hour and has an estimated stack gas flow of 986 m3/minute

and the feed rate of the soil into the incinerator will be 3,400 g of soil/hour. Using the EPA

uncontrolled source emission factors given below, estimate the hourly emissions that would be

expected in the flue gas of this incinerator if no air pollution control equipment were used.

Pollutant Emission Factor

VOCs 0.1 g VOCs / kg VOC in waste soil feed

Metals (total) 50.0 g metals / kg metals in waste soil feed

HCl 1.03 g HCl / g Cl in waste soil feed

HF 1.05 g HF / g F in waste soil feed

SO2 2.00 g SO2 / g S in waste soil feed

PM 11,750 mg PM / m3 of flue gas

CO 0.05 kg CO / MMKJ

NOx 0.15 kg NOx / MMKJ

Altitude

(feet)

Air Temp

(°°°°F)

0 56.5

250 58.0

500 60.3

750 61.5

1 000 62.0

1 250 62.0

1 500 61.6

1 750 61.2

2 000 60.8

Problem 6.3 (12.5 pts.)

An office park complex operates and maintains numerous hot water boilers within its various

buildings. Although this complex has conducted emissions inventories and reported emissions

for several years, it has never attempted to quantify the emissions resulting from these boilers.

All boilers are natural gas fired and are uncontrolled (no pollution control equipment is used).

The following boilers represent the three different types of boilers that are used. Using

emission factors that you find in EPA’s AP-42 documents, calculate the annual emissions that

occurred from these three boilers (Note: In order to calculate the emissions from all boilers

located within this complex, the approach for these three boilers would need to be applied to

the remaining boilers and their operating data.).

Boiler #10 Boiler #12 Boiler #30

Annual Fuel Consumption (MSCF) 67, 959 1,006 1,375

Hours of Operation 4,643 5,400 8,760

MSCF = 106 standard cubic feet

The design capacities of boilers #10, #12, and #30 are 61.2 MMBtu/hr., 3.6 MMBtu/hr., and

0.25 MMBtu/hr., respectively.

Problem 6.4 (20 pts.)

An oil refinery currently has one stack (Stack 1) emitting sulfur dioxide. The level of exposure to

nearby populations from the sulfur dioxide emissions is not known. The facility would like to

determine the potential impact of its emissions on various downwind receptors and to identify

a monitoring site location that could possibly measure the maximum occurrence of a downwind

sulfur dioxide concentration at ground level. This facility is the only known source of sulfur

dioxide in the region.

The refinery is located in a rural area (see the generalized figure included), and is situated in a

river valley with relatively flat terrain. A river runs northeast to southwest along the western

boundary of the refinery, and a small lake is located just south of the refinery. A major four-

lane highway and a railroad serve the area and run northeast to southwest. The populations

living nearest to the refinery include the following:

1) Small town located 1.5 km east of the existing refinery stack 1

2) Farm located 950 meters directly to the west of the existing refinery stack 1

3) Summer camp facility at the small lake located 540 meter to the south of the existing

refinery stack 1

Stack 1 currently emits sulfur dioxide at a rate of 4.78 grams per second. This stack is 35.0

meters high and has an inside diameter of 1.56 meters. The stack gas velocity is 13.2 meters

per second, and stack gas temperature is 394 Kelvin. The stack is located 10 meters from the

north property boundary, 33 meters from the west property boundary, 160 meters from the

south property boundary, and 60 meters from the east property boundary.

The meteorology of the area can be summarized as follows:

The average annual ambient temperature is 18.3°C.

During different months of the year, the predominant wind direction, average wind speed

(at 10 meters) and the typical stability characteristics are shown in the following table.

Month Wind Direction Wind Speed (m/s) Stability Class

January NNW 3 D

February N 3 E

March W 6 D

April SW 4 C

May SW 3 C

June S 4 B

July SSW 4 B

August SW 2 A

September SSE 4 B

October E 4 D

November NW 3 D

December NNW 2 E

Use the AJ Designer Dispersion model (used in HW #4) with the method referred to as “Method

1” (also given in HW #4) to calculate the sigma-y (σy) and sigma-z (σz) dispersion coefficients,

and determine the following:

1) Which receptor appears to experience the highest concentration of sulfur dioxide?

2) How far downwind from the stack would be a good location to place an SO2 monitor if

you wanted to be able to measure the highest concentration of SO2 occurring in the

month of February?

Figure for Problem 6.4. Generalized location of oil refinery and its immediate surrounding

area. The proposed stack #2 is not being considered in problem 6.4.