Sampling Conditioning System for Extractive CEMS

Continuous Emission Monitoring SystemFrom Understanding to Implementation

CEMSSanjeev RaiPerma PureJan 18, 2017

AGENDA

• Different Application Different CEMS

• Importance of sampling system

• Moisture Removal System

• CEMS comparison Germany/China with • CEMS comparison Germany/China with India

• Common CEMS Installation Issues in India

• Maintenance of CEMS system in India

• Portable Conditioning System for Regulator

• Key Points for Regulators

Different Applications Require Different Approaches to CEMS

• What pollution control systems are now in place?

– FGD? Wet or dry injection?

– SCR? What is ammonia slip level?

– ESP or baghouse? What is particulate level?– ESP or baghouse? What is particulate level?

• What is the fuel source?

– How much sulfur content? (oil, coal)

– Water % by volume? (8-12% normal)

– Trash or other waste (biomass)?

• What is the measurement for?

– Regulation (CEMS)

– Process control

© Perma Pure, 2012 Page 5

Why Does Pollution Control Matter for CEMS?

1. Pollution control systems require BEFORE and AFTER measurements for process control and verification.

2. Low-level analytes require more accurate analyzers ANDmore accurate sample conditioning systems.

3. Key acid gases are highly water soluble.

– NO2 and SO2

– HCl and Hf

4. Catalysts and reagents can create unintended consequences with downstream reactions.

– E.g., Ammonia Injection

© Perma Pure, 2012 Page 7

SO2 Solubility in Water100100

9090

8080

7070

6060

5050

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© Perma Pure, 2012 Page 5

Temperature (Deg. C)Temperature (Deg. C)

5050

4040

3030

2020

1010

0000 1010 2020 3030 4040 5050 6060 7070 8080 9090 100100

SO

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ANALYSER SYSTEM

Importance of Sampling System

• Gas Sample Conditioning Systems is an integral part of the Analyser System. Analyser is as good as it’s Sample.

• Tighter emission norms means more accurate measurement.

• It is legendary within the analyzer community that sampling causes 80% of the process analyser downtime( Clevett, K.J. causes 80% of the process analyser downtime( Clevett, K.J. 1986. Process Analyser Technology.New York: Wiley Science)

• Analyser reliability have improved substantially but the system reliability has not improved much because the sampling system are still the same

Gas Cooling Characteristic

• Gas cools down from 300 deg C to 30 Deg C in about 120 mm of bare tubing1

• Gas cools down from 300 deg C to 30 Deg C in about 500 mm of insulated tubing1C in about 500 mm of insulated tubing1

• Only way to avoid condensation is to have heated sample line which are properly terminated and do not have cold spots

• 1 Gross and Bundschuh

Moisture Removal Systems

Condensor

Condensers cool the gas below the dew point, and then remove the condensed liquid water from the gas stream. Water removal is performed automatically to prevent filling the condensate trap and flooding the sampling line.

Permeation Dryer

Permeation dryers are constructed using Nafion®, a material that selectively allows the mass transfer of water vapor from the sample gas through the tube membrane to dry purge gas flowing in an outer tube in the opposite direction.

About Nafion

• Nafion is a copolymer of Teflon and Sulfonic acid and is highly resistant to chemical attack while selectively permeating water through the membrane.

• Nafion removes water by absorption as water-of-hydration.

• Because this is a specific chemical reaction with water, the process is very selective and gases being dried or processed are usually entirely unaffected.

• The transfer of moisture is driven by the differential water vapor pressure between the membrane sides

Nafion Permeation Dryers Selectivity

Totally Retained by Nafion®Totally Retained by Nafion®

Atmospheric GasesAtmospheric Gases

HalogensHalogens

HydrocarbonsHydrocarbons

ArAr He HHe H22 NN22 OO22 OO33

BrBr22 ClCl22 FF22 II22Simple forms (alkanes)Simple forms (alkanes)

Inorganic AcidsInorganic Acids

Other OrganicsOther Organics

OxidesOxides

SulfurSulfur

Toxic GasesToxic Gases

HClHCl HF HNOHF HNO33 HH22SOSO44

Aromatics Esters EthersAromatics Esters Ethers

CO COCO CO22 SOSOXX NONOXX

COS HCOS H22S S MercaptansMercaptans

COClCOCl22 HCN HCN NOClNOCl

Typical Combustion Analytes

Nafion.swf

Nafion Dryer Construction

1. Tube and shell design2. Sample is passed through

Nafion tube3. Dry purge gas is passed

through Shellthrough Shell4. The dry Purge gas sweeps

away the moisture through Nafion tube.

5. The sample gas is dried while the purge gas is humidified

CEMS System Comparison with China/Germany and IndiaChina/Germany and India

CEMS Installation Germany

CEMS Installation Germany

Heated Sample line is connected to probe without any cold spot and it is installed right upto the cooler inlet

CEMS Installation China

CEMS Installation China

Pre SCR installation

• COMMON CEMS INSTALLATION ISSUES IN INDIAISSUES IN INDIA

CEMS Installation in India

HEATED PROBE BUT NO HEATED LINE BETWEEN PSHS AND PROBE

CEMS Installation in India

HEATED SAMPLE LINE HEATED PROBE BUT NEVER POWERED ON SINCE INSTALLATION ( 5 YEARS OLD INSTALLATION)

CEMS Installation in India

HEATED PROBE HEATED LINE BUT NOT PROPERLY TERMINATED

CEMS Installation in India

Non Heated Line Installed Between Probe to blowback

CEMS Installation in India

Condensate Pot Installed Between Blowback and Analyser

CEMS Installation in India

CONDENSATION IN THE SAMPLE LINE INSDE ANALYSER ABINET

CEMS Installation in India

No Heated Sample Line upto the cooler

CEMS Installation in India

Perisaltic pump was regularly failing so they iremoved pump and installed autodrain system

CEMS Installation in India

NO HEATED SAMPLE LINE BEFORE NAFION DRYER

Nafion System Installation

Portable Sample Conditioning System for Onsite Testing

Key Points for Regulator

How to ensure measurement accuracy

Measurement accuracy is more affected by sampling system than by analyzer

Moisture to be removed only in cooler or in Nafion Moisture to be removed only in cooler or in NafionDryer

All the component in the sampling system before moisture separation should be heated, no cold spot

No Condensate Pot/ moisture trap to be present in sampling system

Key Point for Regulator

CEMS is a system and not merely an instrument , if any component of system is not installed as per the best practice the accuracy will get compromised or system will fail much before the useful life.

As permitted levels of Sox and NOx are continually being reduced, it is even important to consider right conditioning technology to get representative sample.

During inspection it is important to look the complete system from probe to analyzer.

Thank You

Sanjeev Rai Sanjeev Rai srai@permapure.com

Mobile:+919910098244