Please I would like you to paraphrase this report for me in an excellent writing without grammer mistake

Please I would like you to paraphrase this report for me in an excellent writing

without grammer mistake

Abstract

The objective of this project is to analyze the removal of H2S from a gas stream by a NaOH solution using a pilot-scale gas absorption column separating CO2 from air using a 0.05N aqueous NaOH solution. The pilot-scale gas absorption column is packed with ½-inch Raschig rings to a height of 4 feet with a 5.5 inch diameter. The effects of inlet gas and liquid flow rates on the gas absorption was investigated to find the parameters that help scrub the highest amount of H2S from a landfill gas stream. NaOH is used for the solution, as it is a strong base that will react with CO2 and H2S irreversibly to produce a solid. CO2 was used in place of H2S since they are similar in size, and they react with NaOH in a similar manner, in addition to CO2 being much safer. At a constant gas flow rate, Kya increased with the increase of liquid flow rate. In addition, at a constant liquid flow rate, Kya also increased with the increase of gas flow rate. As the flow rate is increased, the trend of Kya reaches equilibrium. Similarly, using H2O to absorb CO2 had the same trend as the NaOH solution. However, the removed CO2 concentration from H2O was less than NaOH solution. The NaOH solution removed twice as much CO2 than H2O.

Background:

Many researches have been done on removing CO2 due to its role in climate change[footnoteRef:1]. As CO2 is very similar to H2S in terms of size and reaction to NaOH, it works as an approximate substitute. In an experiment by Yazdanbaksh, et al., an absorber column was used with 1.2 m of packing height filled with 1 cm Raschig rings, and a column diameter of 10 cm, was used to remove CO2 from industrial gas streams by an NaOH solution[footnoteRef:2]. A counter-current flow rate configuration was used, and the flux was calculated using the equation: [1:

“Overview of Greenhouse Gases.” EPA. Environmental Protection Agency, 20 Jan. 2017. Web. 01 Feb. 2017.] [2: Yazdanbakhsh, F., Soltani, A., and Hashemipour, H.. “Investigating effects of gas flow rate and carbon dioxide composition in chemical absorption of carbon dioxide in a packed bed using sodium hydroxide.” Proc. of 10th International Conference on Environmental Science and Technology, Kos island, Greece. N.p., n.d. Web. 22 Jan. 2017.]

(Eq. 1)

G is superficial molar velocity of gas, NCO2 is mass transfer flux of CO2 – amount of CO2 transferred per area and time, Z is a packed bed height, and a is the specific surface area of the packing – the surface area of the packing per volume of packing.

From their research, they found out the liquid flow rate has no effect on the concentration of CO2 at the outlet gas stream. However, the gas flow rate affected the concentration of CO2. As the gas flow rate increased the concentration of CO2 in the outlet gas stream also increased.

In another experiment by Yaminah Jackson, recording data for a COMSOL simulation of CO2

removal from air stream using water, using (Eq. 2) as a basis for results.[footnoteRef:3] [3: Jackson, Yaminah Z. Modeling Gas Absorption. Worcester Polytechnic Institute, 24 Apr. 2008. Web. 24 Jan. 2017.]

(Eq. 2)

is the overall mass transfer coefficient based on the gas phase driving force (mol/m3·hr), V is the average vapor molar flow rate through the column, S is the cross-sectional area of the column, and HOG is the height of a transfer unit.

According to the article by Yadolla and Hosseini, they used an NaOH solution in order to remove the CO2 from air.[footnoteRef:4] [4: Tavan, Yadollah, and Seyyed Hossein Hosseini. “A novel rate of the reaction between NaOH with CO2 at low temperature in spray dryer.” Petroleum (2016): n. pag. Web. 3 Feb. 2017.]

CO2 (l) + 2NaOH (l) Na2CO3(s) + H2O (l) (Eq. 3)

From the equation 3, when CO2 reacts with NaOH, it makes Na2CO3, which is a salt, and H2O. As it produces a salt in the reaction, the y* value is 0. Furthermore, increasing the NaOH concentration leads to a high CO2 removal efficiency.

Materials and Methods:

A 180 L tank was filled with a 0.05N aqueous NaOH solution. The NaOH solution was created by combining 360 g of NaOH in two liters of water as a concentration. The solution was transferred to the tank where it was mixed thoroughly while adding 178 L of water. The solution was pumped through the packed bed column at a variety gas flow rates with constant liquid flow rate and vice versa.

First, a gas (air and CO2) flow rate was chosen and was kept constant while the liquid flow rate was varied. Measurements of the entering and leaving gas concentrations were taken in CO2 ppm using LabQuest probes. The concentration measurements were taken constantly and recorded when steady state was reached. Steady state was considered reached when the concentration had not changed in 20 seconds. Secondly, a liquid flow rate was chosen and was kept constant, while varying the gas flow rates. As before, CO2 concentration measurements were taken using the probes when steady state was reached. Steady state was reached in around 200 s. After measurements were taken using the NaOH solution, the solution was drained from the tank, and the column by flowing water through the system. Measurements were taken using water as the liquid in the column.

Results and Discussion:

The overall mass transfer coefficient, Kya was calculated using equation (7) after rearranging equations (4-6). The detailed calculations are in Appendix IV.

(Eq. 4)

(Eq. 5)

for very dilute systems (Eq. 6)

(Eq. 7)

where is the height of the column, HOG is the height of a transfer unit, NOG is the number of transfer units, is the average molar flow rate of the gas through the column, and S is the cross-sectional area of the column.

NaOH reacts with CO2 irreversibly to produce Na2CO3, thus y* is 0, which means CO2 is diluted.

For a constant gas flow rate, Kya increased as the NaOH solution flow rate increased (Figure 1). At constant gas flow rate of 6.2 mL/s, and a 26.3 mL/s liquid flow rate, which are the smallest flow rates tested, Kya was found to be 23 mol/m3s. At 60 mL/s liquid flow rate, which is the highest flow rate tested, Kya was found to be 25 mol/m3s. The slope between 26.3 mL/s and 44 mL/s is 0.072 mol/m3-mL, and the slope between 44 mL/s and 60 mL/s is 0.042 mol/m3-mL. The slope decreases with increasing liquid flow rate. If there is more liquid flow rate, there is more NaOH, thus there is more chance to transfer CO2 concentration from gas to liquid in the column. If there is more CO2 coming from the gas, then Kya increases more. However, when there is more CO2 than NaOH can hold, then Kya will reach equilibrium.

Figure 1: Kya of CO2 removal from air using a 0.05N aqueous NaOH solution at different flow rates with constant gas flow rate at 6.2mL/s.

For a constant liquid flow rate, Kya increased as the gas flow rate increased (Figure 2). At 26.3 mL/s liquid flow rate, Kya increased by 19 mol/m3s when the gas flow rate was increased from 1.3 mL/s to 6.2 mL/s. When the liquid flow rate was constant at 60 mL/s, Kya increased by 19 mol/m3s when the gas flow rate was increased from 1.3 mL/s to 6.2 mL/s. The increased value of Kya is similar, which is 19 mol/m3s even though constant liquid was increased from 26.3 mL/s to 60 mL/s. When there is more gas flow rate, there is more chance to transfer CO2 concentration from gas to liquid. However, if there are no more spaces for the CO2 concentration transfer, then Kya will reach equilibrium.

Figure 2: Kya of CO2 removal from air using a 0.05N aqueous NaOH solution when holding the liquid flow rate constant while varying the gas flow rate.

At the smaller gas flow rates, there is less Kya change (Figure 3). At 1.3mL/s of constant gas flow rate, the difference of Kya with varied liquid flow rate was 1.27 x10-2 mol/m3s. However, at 6.2 mL/s of constant gas flow rate, the difference was 2.08 mol/m3s. Therefore, the gas flow rate is more effective to remove CO2 compared to liquid flow rates.

Figure 3: Kya of CO2 removal from air using an NaOH solution at different liquid flow rates with constant gas flow rate.

The H2O solution had a similar trend as the NaOH solution at constant gas flow rates (Figure 4, Appendix II). At constant gas flow rate, Kya increased with the liquid flow rate. The trend of Kya was same at constant liquid flow rates (Figure 5, Appendix II). However, the value of Kya was less than the NaOH solution value. At the same liquid flow rate of 60 mL/s and a gas flow rate of 6.2 mL/s, the NaOH solution had a Kya value of 26 mol/m3s, while H2O had 17.8 mol/m3s. This means that there was less transfer of concentration CO2 in H2O liquid compared to NaOH solution. In addition, the NaOH solution removed twice as much CO2 from air than the H2O solution (Figure 6, Appendix II).

When 10000 ppm of CO2 gas inlet was used, Kya almost doubled in comparison to 5000 ppm inlet (Figure 7, Appendix II)

To calculate the flooding velocity, Eq (8) was used.

From this equation, the flooding velocity was found to be 0.0184 m/s. The detailed sample calculation is in Appendix V.

Appendix I.

PFD

Appendix II.

Figure 4: Kya of CO2 removal from air using water at different liquid flow rates with constant gas flow rates.

Figure 5: Kya of CO2 removal from air using water at different liquid flow rates with a constant gas flow rate of 1.3 mL/s

Figure 6: Comparison of the CO2 concentration at the gas outlet for the NaOH solution and water

Figure 7: Kya of CO2 removal using a concentration of 10000 ppm as desired for H2S removal concentration, compared to a concentration of 5000 ppm.

Appendix III.

Table 1 Raw data for the gas flow rate held constant (at two different rates) with varying NaOH solution flow rates. Includes the resulting CO2 concentrations in ppm, height of the column and cross-sectional area of column.

L (mL/s)

CO2 (mL/s)

air (mL/s)

CO2 out (ppm)

CO2 in (ppm)

Z (m)

S (m2 )

26.3

6.2

1233.8

1590

5000

1.2

0.008

44.0

6.2

1233.8

1370

5000

1.2

0.008

60.0

6.2

1233.8

1300

5000

1.2

0.008

26.3

6.2

1233.8

1580

5000

1.2

0.008

37.4

6.2

1233.8

1500

5000

1.2

0.008

44.0

6.2

1233.8

1400

5000

1.2

0.008

60.0

6.2

1233.8

1300

5000

1.2

0.008

60.0

1.3

258.7

5000

1.2

0.008

60.0

6.2

1233.8

998

4953

1.2

0.008

60.0

6.2

1233.8

992

4904

1.2

0.008

26.3

1.3

258.7

5000

1.2

0.008

26.3

6.2

1233.8

1280

4940

1.2

0.008

26.3

6.2

1233.8

1282

4928

1.2

0.008

44.0

6.2

1233.8

1087

4941

1.2

0.008

44.0

1.3

258.7

5000

1.2

0.008

44.0

6.2

1233.8

1074

4960

1.2

0.008

Table 2 Kya results from the measured data of liquid flow rate, CO2 flow rate, air flow rate and molar fraction change for CO2 in aqueous NaOH solution.

L (mL/s)

CO2 (mL/s)

air (mL/s)

yin – yout

Kya (mol/m3·s)

26.3

6.2

1233.8

0.00224

22.94

44.0

6.2

1233.8

0.00238

24.42

60.0

6.2

1233.8

0.00243

24.89

26.3

6.2

1233.8

0.00224

23.00

37.4

6.2

1233.8

0.00230

23.54

44.0

6.2

1233.8

0.00236

24.22

60.0

6.2

1233.8

0.00243

24.89

60.0

1.3

258.7

0.00327

7.03

60.0

6.2

1233.8

0.00260

26.61

60.0

6.2

1233.8

0.00257

26.32

26.3

1.3

258.7

0.00328

7.05

26.3

6.2

1233.8

0.00240

24.62

26.3

6.2

1233.8

0.00239

24.53

44.0

6.2

1233.8

0.00253

25.93

44.0

1.3

258.7

0.00328

7.05

44.0

6.2

1233.8

0.00255

26.14

Table 3 Raw data for the gas flow rate held constant (at two different rates) with varying water flow rates. Includes the resulting CO2 concentrations in ppm, height of the column and cross-sectional area of column.

L (mL/s)

CO2 (mL/s)

air (mL/s)

CO2 out (ppm)

CO2 in (ppm)

Z (m)

S (m2)

26.3

6.2

1233.8

2537

4983

1.22

0.008

44.0

6.2

1233.8

2380

4959

1.22

0.008

60.0

6.2

1233.8

2338

4983

1.22

0.008

26.3

1.3

258.7

2340

5032

1.22

0.008

44.0

1.3

258.7

2210

5026

1.22

0.008

60.0

1.3

258.7

2134

5026

1.22

0.008

26.3

1.3

258.7

2390

5038

1.22

0.008

44.0

1.3

258.7

2231

5026

1.22

0.008

60.0

1.3

258.7

2137

5026

1.22

0.008

Table 4 Kya results from the measured data of liquid flow rate, CO2 flow rate, air flow rate and molar fraction change for CO2 in water.

L (mL/s)

G (mL/s)

A (mL/s)

yin-yout

Kya (mol/m3· s)

26.3

6.2

1233.8

0.00160

16.45

44.0

6.2

1233.8

0.00169

17.34

60.0

6.2

1233.8

0.00173

17.79

26.3

1.3

258.7

0.00177

3.80

44.0

1.3

258.7

0.00185

3.97

60.0

1.3

258.7

0.00190

4.08

26.3

1.3

258.7

0.00174

3.73

44.0

1.3

258.7

0.00183

3.94

60.0

1.3

258.7

0.00190

4.07

Appendix IV.

Converting ppm to mole fractions:

NOG was found from the change in mole fraction between the top and bottom of the column:

Finding the molar flow rates of the vapor, CO2 + air:

For the incoming stream:

Calculating overall mass transfer coefficient:

Appendix V.

Flooding velocity

The superficial gas velocity at flood is correlated by

= superficial gas velocity at flood, m/s

= total surface area packing, bed

= fractional voids in dry packing

g = gravitational constant, 9.8067

= liquid and has densities,

L/ G = liquid and gas flow ratio

= liquid viscosity, mPa*s (or cP)

= 1.225 kg/m3, = 1.98 kg/m3.There is 0.05% of CO2 is in the mixed air, so the density can be assumed as air. Therefore, the density of gas is 1.225kg/m3.

The density of liquid can be assumed as water density because in aqueous NaOH solution, there is 0.2% of NaOH and 99.8% of water. Therefore, the density of liquid is 1 kg/m3.

In trial 1, the liquid volumetric flow rate was 26.3mL/s and the gas volumetric flow rate was 103.2 mL/s.

From the generalized correlation of flood points, packed columns graph[footnoteRef:5], the x-axis is 0.282, therefore the y-axis is 0.06. [5: Generalized correlation of flood points, packed columns, Sherwood et al., Ind. Eng. Chem. 30, 768 (1938).]

From the characteristics of dumped tower packing chart, = 370, = 0.64. The density of has is calculated in Eq. 6. = 1.225kg/m3, g = 9.8067m/s, = 1kg/m3, and =1cP.

= 3.403 x 10-4 m2/s2

= 0.0184 m/s

Gas 6.2mL/s 26.3 44.0 60.0 16.44723466160312 17.34285121757167 17.78650305955781 Gas-1 1.3mL/s 26.3 44.0 60.0 3.795511958310095 3.970535838768211 4.077797265394337 Gas-2 1.3mL/s 26.3 44.0 60.0 3.733391817376836 3.940898760780612 4.073563159807454

H2O flowrate (mL/s)

Kya (mol/m3·s)

Trial 1 26.3 44.0 60.0 3.7955119583101 3.970535838768209 4.077797265394341 Trial 2 26.3 44.0 60.0 3.73339181737684 3.940898760780611 4.07356315980745

Liquid flowrate (mL/s)

Kya (mol/m3·s)
H2O 2537.0 2380.0 2338.0 26.3 44.0 60.0 NAOH 998.0 1282.0 1074.0 60.0 26.3 44.0

Concentration of CO2 in outlet (ppm)

Liquid flowrate (mL/s)

10000 ppm model 30.0 50.0 70.0 0.0281211215530425 0.028829813515346 0.0290998429631448 5000 ppm model 30.0 50.0 70.0 0.0114808947401888 0.0122233681595977 0.0124596548178303

NaOH flow rate (mL/s)

Kya (mol/m3·s)

Trial 1 26.3 44.0 60.0 22.93607092378319 24.41758796794011 24.88902487041074 Trial 2 26.3 37.4 44.0 60.0 23.00340794132821 23.54212007899421 24.215550249345 24.88902487041074 Trial 3 30.0 50.0 70.0 0.00704679667033133 0.00704679667033133 0.00703407630039255 Trial 4 30.0 50.0 70.0 0.0246215717661307 0.0259282738709048 0.0266082305416003 Trial 5 30.0 50.0 70.0 0.0245276646452005 0.0261431807186952 0.0263202599197678

Liquid flow rate (mL/s)

Kya (mol/m3 · s)

Liquid 60 mL/s 1.3 6.2 6.2 7.03407630039255 26.6082305416003 26.3202599197678 Liquid 26.3 mL/s 1.3 6.2 6.2 7.04679667033133 24.6215717661307 24.5276646452005 Liquid 44 mL/s 6.2 1.3 6.2 25.92827387090472 7.04679667033133 26.1431807186952

Gas flowrate (mL/s)

Kya (mol/m3 ·s)

Gas 1.3mL/s 60.0 26.3 44.0 7.03407630039255 7.04679667033133 7.04679667033133 Gas 6.2mL/s 60.0 60.0 26.3 26.3 44.0 44.0 26.6082305416003 26.3202599197678 24.6215717661307 24.5276646452005 25.92827387090472 26.1431807186952

Liquid flowrate (mL/s)
Kya (mol/m3 ·s)

CHE 415: Chemical Engineering Laboratory
Winter

018

GAS ABSORPTION

Equipment Description

A packed tower for gas absorption experiments is located on the east wall of Johnson 214. The tower is packed to a height of 4 feet with ½” Raschig rings and has an inner diameter of 4 inches. Pure carbon dioxide gas is supplied from a gas cylinder and regulator. The carbon dioxide is mixed with utility air and fed to the bottom of the column. NaOH solution is pumped to the top of the tower from a Nalgene feed tank. Rotometers, mounted on a control panel to the right of the tower measure carbon dioxide, air, and liquid flow rates entering the column. The valves for controlling each flow rate are located directly below their respective rotometers. Calibration data for each flowmeter are provided in Table 1. A manometer with taps at the top and bottom of the column measures the pressure drop across the column.

Two types of continuous-flow gas absorption experiments can be performed with the packed tower. First, the gas flow rate is kept constant while the liquid flow rate is varied. Second, the liquid flow rate is kept constant while the gas flow rate is varied. For both experiments, the gas mixture entering the column is fixed at 0.5 mole % carbon dioxide.

Figure 1. Gas absorption pilot plant in JOHN 214. The 180 L reservoir at left feed a pump that both recycles fluid back to the tank and delivers it through a rotameter and to the 4 ft packed section. Air (from house air) and CO2 (from the cylinder at left) flow through rotameters, then combine and feed the column bottom. CO2 sensor are positioned at both column feed and outlet. A gas sample port is located on the inlet.

Equipment Operation

Note: Personal protective equipment is of paramount importance in this lab. In addition to the lab minimum of protective eyewear and a lab coat, you will wear an apron and face shield during concentrated solution preparation (see below) and nitrile gloves if operating or working around the batch reactor or PFR. Be sure to identify roles so that the dry working lab space and computer are not exposed to gloves of chemicals.

Your lab group will develop detailed procedures for operating the equipment and acquiring the data. Therefore, you should study the equipment carefully before performing any experiments.

The sodium hydroxide scrubbing solution should be prepared at the start of the lab session across from the fume hood in the chem prep room (JOHN 210D). The feed reservoir volume is 180 liters. Determine in advance the mass of sodium hydroxide pellets required, mass the pellets on the top-loading balance, and then dissolve using the provide stir plate and 2 L beaker. Make sure the pellets have completely dissolved, then transfer the solution carefully to the provided Nalgene bottle(s). This concentrate will be diluted in the feed reservoir.

CAUTION! Significant heat evolves when NaOH dissolves in water! Start with cold water and continuously stir while
slowly adding pellets to the water
to dissipate the heat of solution. The resulting concentrated NaOH solution is also extremely caustic – wear appropriate PPE (double gloves, goggles, face shield, and lab coat) at all times when mixing and handling the solution. Transport the solution in capped 1 L bottles.

Fill the feed reservoir approximately half-full with process water and turn on the recirculation pump. Carefully pour the concentrated sodium hydroxide solution into the tank while continuing to fill the tank with water from hose (wear your PPE and pour along the side of the tank to prevent splashing). NOTE: Do not walk away from a reservoir as you fill it with a hose. Fill the tank to 180 liters. Continue mixing the solution using the pump and the column bypass line. Determine when you think it’s sufficiently well-mixed. If desired, liquid samples leaving the packed tower can be removed through the sampling line at the bottom of the tower.

Figure 2. Chemical preparation area for concentrated NaOH solutions. Be extra careful and communicative while working in close quarters with others. Leave the workspace as you found it, with stir plate, stir bar, graduated cylinders, etc.

IMPORTANT: Gas composition is assessed using Vernier LabQuest® units with CO2 sensors. The power requirements of the CO2 sensors allow only one CO2 probe per LabQuest®, so two are provided. During column operation, water can collect near the sensors, potentially damaging them or leading to measurement error. Make sure that any time water is flowing through the column, the gas is flowing as well. If you have trouble with the CO2 probe readings:

1. Verify that all inlet gas plumbing is connected and leak free

2. Verify that there is not liquid near the inlet and outlet CO2 probes

3. Double-check your calcs for total flow and %CO2

4. Pull probe and check for 400 ppm

5. Contact instructor if problems persist

Shut Down

Turn off the carbon dioxide gas cylinder and bleed the pressure in the carbon dioxide delivery line. Pump out the NaOH solution to the drain using the bypass valve behind the panel. Add fresh water to the feed tank until the tank is one-third full. Pump water though the system to flush sodium hydroxide solution from the pump, column packing, and tubing.

Appendix I. Rotameter Calibration

Do not attempt to calibrate the rotameters and assume the data below is sound.

Table 1. Rotameter calibration data at 21 oC for the packed gas absorption tower.

Flow (mL/s)

MeterAir*

*CO

*MeterWater

5976.21511.0

1019316.02017.2

1528626.42520.3

2037636.73026.3

2546249.13532.3

407034037.4

508484540.0

7011015044.0

901303

*CO
2

measured at middle of the ball

**Air measured from bottom disc

Flow (mL/s)

Note:

The calibration data does not cover the full range of the rotometers. Plot out this data before the first laboratory session, fit flow rate vs. scale reading data for each rotometer to determine the linear range of each. Decide on the range of gas and liquid molar flowrates you expect to use in the pilot-scale absorption tower before you begin the experiments.

� Performed by Dusty Berggren, March 2009

CHE 415: Chemical Engineering Laboratory
Winter

018

GAS ABSORPTION

Equipment Description

Equipment Operation

Your lab group will develop detailed procedures for operating the equipment and acquiring the data. Therefore, you should study the equipment carefully before performing any experiments.

1. Verify that all inlet gas plumbing is connected and leak free

2. Verify that there is not liquid near the inlet and outlet CO2 probes

3. Double-check your calcs for total flow and %CO2

4. Pull probe and check for 400 ppm

5. Contact instructor if problems persist

Shut Down

Appendix I. Rotameter Calibration

Do not attempt to calibrate the rotameters and assume the data below is sound.

Table 1. Rotameter calibration data at 21 oC for the packed gas absorption tower.

Flow (mL/s)

MeterAir*

*CO

*MeterWater

5976.21511.0

1019316.02017.2

1528626.42520.3

2037636.73026.3

2546249.13532.3

407034037.4

508484540.0

7011015044.0

901303

*CO
2

measured at middle of the ball

**Air measured from bottom disc

Flow (mL/s)

Note:

� Performed by Dusty Berggren, March 2009

Strong Foundations Engineering, Inc.

| T 541-737-4791 | http://cbee.oregonstate.edu |

SUBJECT:
Removal of CO2 from Air in a Packed Tower

A local landfill is planning to install a new packed tower to process a 250 SCFM landfill gas stream that contains about 1.0% hydrogen sulfide. The hydrogen sulfide needs to be scrubbed from the gas stream to allow its use in a solid-oxide fuel cell. They are considering 0.05N aqueous NaOH as their scrubbing solution and have requested our assistance to perform empirical and predictive analyses using a 0.5% CO2 in air mixture to model the proposed system. Your assignment is to use the pilot-scale gas absorption unit in the Unit Operations Laboratory to investigate the influence of solution and gas flow rates on column performance and use that information to inform a scale-up design. The packed tower has a 4-ft packed section with ½-inch Raschig rings.

The pilot column has CO2 probes that measure the inlet and outlet concentrations. Historically, they have had reliability issues, so be sure to study the relevant documentation to understand their operation. The SOP includes gas and liquid rotometer calibrations. Planning, preparation, and understanding theoretical underpinnings are critical.

Your team is asked to provide:

1. Theoretical and literature analysis to predict results when using a NaOH scrubbing solution at the pilot scale, e.g. mass transfer area, mass transfer coefficients, flux, etc. (be sure to consider equilibrium conditions, e.g. y* and rate limiting diffusion steps for the case of reaction in the liquid phase)

2. The dependence of the overall mass transfer coefficient for CO2 on the liquid and gas superficial molar velocities

3. The dependence of outlet gas composition on the liquid and gas superficial molar velocities

4. Limited investigation of the role of NaOH on resistance to mass transfer, e.g. process performance using only water. We suggest that you make one or two runs with water and compare and briefly report on percent removal at the same liquid and gas flowrates.

5. Proposed design parameters for a packed column capable of treating the landfill gas stream described above using an NaOH scrubbing solution, with predicted contaminant gas concentrations at the outlet, and definition of the adequate operational envelope to ensure safe operation of the column, including a prediction of flooding point flow rates at extremes of gas/solvent flows

CHE 415
School of CBEE
Oregon State University

TECHNICAL WRITING GUIDELINES

CHE 334 (where appropriate), CHE 415, and CBEE 416

Unacceptable basic mistakes:

· Misspelled words

· Lack of introduction for a figure/table/equation in the preceding text

· Lack of title and/or detailed caption on a figure or table

· Unreasonable number of significant figures reported in Abstract/Conclusions

· Decimal written without leading zero

· Incomplete web site reference (site, date accessed, comments if appropriate)

Writing

· PROOFREAD YOUR WORK BEFORE YOU SUBMIT IT.

· Don’t write in the first person.

· Avoid starting sentences with prepositions, thereby being more direct and avoiding commas.

· No figures, tables, equations, or footnotes in the abstract.

· Introduce figures, tables, equation, etc., in the preceding text.

· All figures need a title below, e.g. “Figure 1”, and caption that explains the figure. Make the caption summarize the relevance to somebody who has not read the report, i.e. it can stand alone.

· Titles for figures, tables, equations, etc., should be capitalized in the text, e.q. “Equation 1”.

· Don’t regurgitate/retype detailed information that is provided in a cited reference, e.g. a standard operating procedure (SOP). Provide sufficient details, but use a proper citation.

· Spell names correctly. If unsure, find out.

· Spell correctly and use the correct word: spellcheck may indicate a word is correctly spelled even if it is the wrong word. Some examples from previous years: “Miss counting”, “out liar”, “descent data”, “asses”, “ingrate”, “verse”.

Calculations and Technical Stuff

· Do not use unusual terms without introducing them first.

· Abbreviations and acronyms need be defined either at first use, or in an appendix with reference.

· Use good judgment in deciding how many significant figures to report, e.g. if you’re using a rotometer to measure flow, don’t report 5 significant figures.

· Embrace terms like “prototype”, “testbed” and “benchtop system”. For example, you might use a prototype gas absorption column to assess mass transfer properties, then “scale up” to an actual system design.

Formatting

· Never write a decimal without a leading zero to ensure it’s not mistaken as an integer: 0.62, not .62.

· Never start a sentence with a number, instead use “Thirty mL were delivered using a pipette.”

· Always put a space between a number and its units. It’s easier to read and avoids alphanumeric confusion, e.g. If I write 6 liters as 6l, it sure looks like the number 61.

· Indent titles and captions on tables and figures and consider using smaller font, e.g. 10 pt, to make them stand out from the surrounding text. Some even use italics.

· Figures and tables should be centered on the page.

· Use “Ca2+”, “Na+”, etc. to represent ions. Elemental sodium (not ionic) would be “Na”, and explosive when added to water!

· One often sees “Enclosure” at the bottom of the page. Is that not from the old days, when you “enclosed” something in the envelope?

· Many struggle in Equation Editor without the ability to put in spaces between numbers and units, etc. Try hitting Ctrl+space bar to put in spaces, or convert the entire equation to text style, which allows spaces.

· Italicize variables, e.g. tb. It makes them stand out better to the reader. Do not italicize numbers.

Technical Report Guidelines

· Abstract

· Background

· Materials and Methods

· Results and Discussion

· Acknowledgements

· Appendices

Some guidance about what these sections look like:

· No Cover Page.

· Abstract is a high-level summary and includes (1) objectives, (2) methods, and (3) results. The goal is 4-6 sentences. Emphasize content: settings, ranges, numbers, units. No references, equations, etc.

· Background should be shorter for CBEE 414 lab reports, with brief theoretical background, then broaden as you move to more open-ended labs and senior projects. Look for previous work on the subject, e.g. have others measured that mass transfer coefficient? How? What did they find? Use footnote references liberally.

· Materials and Methods provides details about what you did. It is written in past tense, a story of what was done, not in first person, not as instructions, and not as bullets. The level of detail should be sufficient to allow another worker to repeat your work without having you physically there. Include equipment, manufacturer, model, equipment schematics/pictures.1 Cite provided documents/SOP.

· Results and Discussion is the section in which you present data, calculations performed, error analysis performed, and what you observe and conclude (trends, issues, etc.). It is where you compare experimental results with theory (or manufacturer-supplied) information. Most plots will be in this section. If there is a design component to your lab, include it in this section.

· Acknowledgements1 are included to (1) thank those that helped you setup equipment, explained equipment, etc., but also to (2) provide a record of who helped you so that your readers might use that information, e.g. Jill knows how to run the gas chromatograph. Be succinct.

· Appendices1 are a location for supporting details. Sample calculations are required and must include assumptions, unit, etc., so the reader can follow and check your computations. They can be hand-written if legible. A spreadsheet printout is not enough. Other content might include copies of raw data, equipment calibration data, non-critical charts, etc.

� Not necessary for CHE 334 reports.

Harding
2018
Oregon State University

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