ammonia (nh3) mitigation using electrolyzed water spray scrubber

21
Ammonia (NH Ammonia (NH 3 3 ) Mitigation Using ) Mitigation Using an Electrolyzed Water Spray an Electrolyzed Water Spray Scrubber Scrubber Gerald Riskowski, Professor, Texas A&M University, Bio. Ag. Eng. Dept. Saqib Mukhtar, Professor, Texas A&M University, Bio. Ag. Eng. Dept. Ahmad Kalbasi, Researcher, Texas A&M University, Bio. Ag. Eng. Dept. Amir M. Samani Majd, PhD Candidate, Texas A&M University, Bio. Ag. Eng. Dept. Waste to Worth Conference, Hyatt Hotel, Denver, CO. April 1-5, 2013

Upload: lpe-learning-center

Post on 25-May-2015

1.035 views

Category:

Education


1 download

DESCRIPTION

Proceedings available at: http://www.extension.org/67656 The objective of this research was to evaluate electrolyzed water as a solution for a lab-scale spray scrubber for removing NH3 from air. A one-stage spray scrubber was fabricated to treat 50 cfm (1.42 m3/min) of introduced mixed NH3-air with an approximate NH3 concentration of 20 ppm. The mixed air was blown, countercurrent, to the 5-ft vertical scrubber body using a fan. Eight scrubber design variables were studied including contact times, nozzle types and scrubber solutions. Three contact times were 0.3, 0.6 and 0.9 s. The two narrow and standard nozzles sprinkled in a full-cone spray pattern but at different angles of 26ᴼ and 52ᴼ, respectively. The scrubber solutions variables tested were reverse osmosis (RO) water and two types of electrolyzed water (50 ppm of total chlorine) with pH = 9.0 and pH = 6.5. The 18 combinations of treatments were tested in three replications and statistically analyzed to investigate the objective. The result showed that all of the experiments were able to mitigate the NH3, but at different efficiencies. The maximum efficiency of 53% was acquired with the narrow nozzle, 0.9s contact time and electrolyzed water with pH = 6.5. Therefore, it was concluded that increasing the contact time, decreasing the pH of electrolyzed water and using the narrow angle, higher flow rate nozzle increased the scrubber efficiency.

TRANSCRIPT

Page 1: Ammonia (NH3) Mitigation Using Electrolyzed Water Spray Scrubber

Ammonia (NHAmmonia (NH33) Mitigation ) Mitigation Using an Electrolyzed Water Using an Electrolyzed Water Spray ScrubberSpray Scrubber

Gerald Riskowski, Professor, Texas A&M University, Bio. Ag. Eng. Dept.

Saqib Mukhtar, Professor, Texas A&M University, Bio. Ag. Eng. Dept.

Ahmad Kalbasi, Researcher, Texas A&M University, Bio. Ag. Eng. Dept.

Amir M. Samani Majd, PhD Candidate, Texas A&M University, Bio. Ag. Eng. Dept.

Waste to Worth Conference, Hyatt Hotel, Denver, CO. April 1-5, 2013

Page 2: Ammonia (NH3) Mitigation Using Electrolyzed Water Spray Scrubber

Introduction

NH3 emission from AFOsAdverse effects on animal and worker healthSource of Odor and Environmental Pollution

Contribute to fine particulate matter formation

Eutrophication of water bodies

Contamination of groundwater

Constituent of nitrous oxide, a potent greenhouse gas

NH3 emission into the atmosphere results in a loss of nitrogen, an essential plant nutrient.

Page 3: Ammonia (NH3) Mitigation Using Electrolyzed Water Spray Scrubber

Introduction

U.S.EPA regulation

- Environmental Planning and Community Right-to-Know Act (EPCRA)

-NH3 and H2S emissions exceeding 45.4 kg (100 lb) in any 24 hour time period are

considered a “reportable Quantity.”

Page 4: Ammonia (NH3) Mitigation Using Electrolyzed Water Spray Scrubber

IntroductionAbatement Technologies

Chemical amendments Hollow fiber mitigation technologies Bio-filtersExhaust air scrubber Packed bed scrubbers Impingement plates scrubbers Fiber beds Cyclonic spray scrubber, Venturi scrubbers Rotating beds

Higher pressure drops and operating costs compared to spray scrubbers

Page 5: Ammonia (NH3) Mitigation Using Electrolyzed Water Spray Scrubber

Objective

To develop and evaluate a lab-scale spray scrubber that uses an electrolyzed water scrubber solution.

Page 6: Ammonia (NH3) Mitigation Using Electrolyzed Water Spray Scrubber

Materials and MethodsThe main set-upThe main set-up

A one-stage spray scrubber

5-ft vertical scrubber body

Page 7: Ammonia (NH3) Mitigation Using Electrolyzed Water Spray Scrubber

Materials and MethodsThe main set-upThe main set-up

A fan blew 50 cfm of mixed NH3& air into the scrubber stream

Approximate NH3

concentration in simulated exhaust air was 20 ppm

Page 8: Ammonia (NH3) Mitigation Using Electrolyzed Water Spray Scrubber

Materials and MethodsTwo Types of Nozzles Used for Nozzles Used for Scrubbing Exhaust AirScrubbing Exhaust Air

Narrow-Angle Full Cone Nozzle

Standard Type Full Cone Nozzle

Page 9: Ammonia (NH3) Mitigation Using Electrolyzed Water Spray Scrubber

Materials and MethodsThe main set-upThe main set-up

Two types of nozzles: A Narrow-Angle Full Cone Nozzle A Standard Type Full Cone Nozzle

Nozzle Narrow-angle Standard Type

Spray pattern Full cone Full cone

Spray angle 26o 45o

Height of spray 30 cm (12”) 15 cm (6”)Droplet size 700-900 µm 200-300 µm

Pressure 190-200 kPa (27.6-29 psi)

190-200 kPa (27.6-29 psi)

Scrubbing solutionflow rate

5.2 L/min (~1.38 gal/min)

0.95 L/min(~0.252 gal/min)

Page 10: Ammonia (NH3) Mitigation Using Electrolyzed Water Spray Scrubber

Exhaust Air

Exhaust Air

Manometer

Air Nozzle

Drainage

Valve

Flowmeter

Pressure Gage P

F

Scrubbing Solution

Contact chamber

Pump

nozzle

Spray cone

F

P

Air Fan

NH

3 C

ylin

der

P

F Air duct

NH3 Analyzer

Preheating System

2

1

Page 11: Ammonia (NH3) Mitigation Using Electrolyzed Water Spray Scrubber

Centrifugal fan

NH3

diffuser

NH3

cylinder

NH3

flowmeter

Air duct

Manometer

Air nozzle

Contact chamber

Spray nozzle

Page 12: Ammonia (NH3) Mitigation Using Electrolyzed Water Spray Scrubber
Page 13: Ammonia (NH3) Mitigation Using Electrolyzed Water Spray Scrubber

Production of Electrolyzed waterProduction of Electrolyzed waterMembrane less Electrolyzed water Electrolyzing regular NaCl solution

In an EW solution, the most effective form of chlorine compounds include hypochlorous acid (HOCl) and hypochlorite ion (OCL-)

HOCl OCl- + H+

Page 14: Ammonia (NH3) Mitigation Using Electrolyzed Water Spray Scrubber

Materials and MethodsExperimentsExperiments

Eight Variables: 54 experiments: 18 scenarios in three

replications- Contact times: 0.3, 0.6 and 0.9

second- Nozzle types: Narrow and Standard- Scrubber solutions: Reverse osmosis

(RO) water, two types of electrolyzed water (50 ppm of total chlorine) with pH = 9.0 and pH = 6.5.

Page 15: Ammonia (NH3) Mitigation Using Electrolyzed Water Spray Scrubber

Materials and MethodsMeasurementsMeasurements

TEI model 17C chemiluminescence NH3 analyzer

Ion Selective Electrode NH3 probe & pH probe

Page 16: Ammonia (NH3) Mitigation Using Electrolyzed Water Spray Scrubber

Results and Discussion:

Treatment #

Treatment VariablesEfficiency

(%)*

Nozzle type Scrubbing solutioncontact time

(s)

1

Narrow-angle

EW, pH 6.5

0.3 37.9 (1.6)

2 0.6 51.9 (3.8)

3 0.9 56.0 (2.7)4

RO

0.3 34.7 (5.5)5 0.6 43.9 (3.6)

6 0.9 49.5 (5.6)

7EW, pH 9.0

0.3 39.0 (0.8)8 0.6 47.1(2.0)9 0.9 51.3(3.6)

Page 17: Ammonia (NH3) Mitigation Using Electrolyzed Water Spray Scrubber

Results and Discussion:

Treatment #

Treatment VariablesEfficiency

(%)*

Nozzle typeScrubbing solution

contact time (s)

10

Standard Type

EW, pH 6.5

0.3 37.9 (0.7)

11 0.6 46.7 (3.3)

12 0.9 43.9 (4.4)

13

RO

0.3 32.1 (2.5)

14 0.6 36.7 (4.8)

15 0.9 39.3 (2.8)

16

EW, pH 9.0

0.3 34.2 (7.7)

17 0.6 39.9 (3.9)

18 0.9 40.6 (0.7)

Page 18: Ammonia (NH3) Mitigation Using Electrolyzed Water Spray Scrubber

Results and Discussion:

Page 19: Ammonia (NH3) Mitigation Using Electrolyzed Water Spray Scrubber

The ammonia removal efficiency of the scrubber ranged from 34% to 56%.

Increasing the contact time, decreasing the pH of electrolyzed water and narrow spray pattern mostly increased the efficiency of the scrubber.

The maximum efficiency of 56% was for: narrow nozzle, 0.9s contact time,Electrolyzed water with pH = 6.5

Conclusions

Page 20: Ammonia (NH3) Mitigation Using Electrolyzed Water Spray Scrubber

A Wet scrubber will be designed from the knowledge gained in laboratory studies will be scaled-up for Field studies

Future Plan

Page 21: Ammonia (NH3) Mitigation Using Electrolyzed Water Spray Scrubber

Acknowledgements & Questions

Funding for this study was made possible by the State of Texas Air Quality Initiative.