October - December 2013

Tai & Chyun NewsletterEnhancing Electrostatic Precipitator Performance

What’s new ? Product Feature I New ESP & Biomass Industry I Page 1 Case Study I New ESP for Bagasse Fired Boiler I Page 3Troubleshooting I Emission & Collecting Efficiency I Page 6Upcoming Event I Taipei Seminar I Page 7More about us ...I Page 8

ISSUE 12

Emission ?

Biomass Industry &

New Electrostatic Precipitator

Product Feature

“ Wastes into utility, wastes into electricity --- that is how agricultural wastes are being looked at now when before the excess rice husks, sugar cane bagasse or empty palm fruit are just being dumped. “

Biomass industry is claimed to be environment friendly with the small carbon footprint to generate power. There is a reduction of air pollutants compared to coal combustion as well as acid rain abatement. Biomass industry turns biomass wastes as fuel, thus reducing the need for landfills.

The stack emission from the biomass combustion is more on the particulate emission. With the government getting stricter on emission regulations and with many of the bio-mass plants are ageing and use outdated technology, a more reliable particulate collec-tor after the boiler will be required for compliance.

October - December 2013

ESP’s role in biomass industry

In practice, different dust collecting devices are used to collect the dust from the gas flow. Electrostatic precipitator or ESP is by far the most efficient equipment for biomass particulate capture with high collection efficiency of 95-99% as compared to wet scrubber’s 50-70%. ESP has low power consumption and can collect sub-micron particles. The dust collected from the ESPs is dry and can be directly used or sold as fertilizer, but the dust collected by the wet scrubber is wet and requires additional costs for drying process.

The ESP supplied to biomass industries is smaller in size compared to other industries. It is mainly composed of two parts: Mechanical and Electrical. The structure includes casing (inlet nozzle, outlet nozzle, hopper, access doors, gas distribution screen), collecting plates, discharge electrodes, insulator and heating system, rapping system, fly ash conveyor system. The electrical units of an ESP include Transformer/Rectifier sets, ESP voltage controller, SCR, thyristor, voltage divider, control panel.

For the operation of the ESP, the alternative current (AC) is converted to direct current (DC) with high voltage. This high voltage current is sent to the discharge electrode which creates corona effect, thereby charging the dust particles carried by the gas passing through it. The negatively charged particles are attracted towards the positive polarity (collecting plate). Thereby, the dust particles are collected.

We had the opportunity to supply new ESPs to customers in the biomass industry in the South East Asian market with high satisfactory results. One of the case study will be shown in the following page. For more in-depth information, please contact our sales representative or our technical team. T&C website is located at www.taichyun.com.tw.

Product Feature

ISSUE 12

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Wet Scrubber Waste

New ESP for Bagasse Fired Boiler

Application Newly Installed ESP for 170 t/h Bagasse Fired Boiler

ProblemA 170 t/h bagasse-fired boiler in Thailand has no air pollution equipment after the boiler. Nearby residents complained as the fly ash is not collected and becomes air borne contribut-ing to air pollution.

Solution 1. Customer decided to install electrostatic precipitator after the boiler. Tai & Chyun was awarded the contract of provid-ing a 2-field ESP with guarantee of dust emission to be below 60 mg/Nm3.

2. Tai & Chyun supplied the engineering, critical ESP parts like collecting plates, discharge electrodes, rapping systems and electrical parts as well as technical direction during in-stallation and commissioning.

3. A local engineering/construction company did the installation.

Case Study

October - December 2013

Project Challenges

1. Work progress was hampered by the site’s weather condition as it was rainy sea-son during the construction period.

2. Lack of suitable storage for all the parts to prevent further corrosion brought about by the weather condition.

3. Insufficient power supply causing power failure which can damage the electrical and control systems.

Results

1. Installation works took around 6 months. 2.Timely completion in-line with the target commercial operation with satisfactory emis-sion level of 14.3mg/ Nm3 -which below the customer’s target of 60mg/Nm3.

3.V-I Curves for the first field were done with the first field having 48kV/1300mA and the second field having 45kV/1400mA with the T/R specification at 72kV/1400mA.

Benefits

1. Clean stack and captured fly ash stopping neighbor complaints.

2. Collected fly ash can be used / sold as fertilizer additive.

Case Study - New ESP (Sugar Plant)

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Mechanical Parts Supply

Structure & Planning

ESP Dry Waste

Commissioning & Testing

Construction & Control

Electrical Parts Supply

“ Electrostatic precipitator is a highly efficient and cost effective filtration device that collects suspended particulates. But there are some factors that

hamper the efficiency of the ESP. Let us try to understand these factors.”

Emission Problem

Troubleshooting

Influencing Factors

October - December 2013

Dust Concentration - Usually the dust concentration is highest in the first field because it is the first area for the inlet air to pass by. The heavy dust suppresses the secondary current (mA) in the first field. Thus, AVC tries to raise the kV level in order to get a higher mA. This high kV level will cause sparking / arcing, thereby lowering the mA to an even lower level. This can be remedied by tuning the AVC parameters, retrofitting to modern AVC, high emitting DE and high frequency T/R set.

Opacity test is another important activity that should be done to know the performance of the ESP. It should be carried out after start-ups and during operations to check if the emission level is within the required regulations. Generally, the level should be below 30~120 mg/m3 (<30~100 mg/m3) depending on the local regulations. If it exceeds the required standards and expectations, the following steps are recommended:

1. Review the gas volume and collecting area if there is an increase in the production volume. 2. Review the dust concentration, particle size and dust resistivity if there is a change in production.3. Review gas sneakage and gas distribution if the operating readings are abnormal. 4. Review dust resistivity, gas volume and collecting area if the ESP readings are good but the emission is poor. 5. Check on the mechanical and electrical conditions

To conclude, the emission level depends on the overall efficiency of an ESP, which is a function of multiple factors. Any factors too high or too low will lead to degradation of ESP’s collecting efficiency, and thereby leading to emission levels exceeding the emission regulations.

For more detailed troubleshooting tips, please contact Tai & Chyun’s technical team.

Emission Problem

Factors influencing the precipitator performance and efficiency:

Dust Resistivity - High dust collecting efficiency occurs within a small range of dust resistivity. If resistivity is too low (<108 ohm-cm), it will lead to re-entrainment of dust collected. When resistivity is too high (>1011 ohm-cm), charging and collection of dust particles is more difficult leading to degradation of ESP efficiency. Resistivity problem can be improved by increasing the size of the ESP, modification of gas temperature, pulse or intermittent energization, rapping frequency, etc.

Particle Size - Collection of finer dust particles is more difficult to deal with because of factors affecting their charging and collection influenced by surface area, porosity and cohesiveness. Re-entrainment can occur easily. This problem can be improved by reducing rapping intensity, increasing the number of electrical sections, gas conditioning (NH3 spraying at upstream), etc.

Gas Distribution - If distribution of gases is not uniform, it might lead to low collection efficiency, excessive reentrainment and excessive sparking. This can be corrected by using corrective devices like multi-layer perforated plates, guide vanes, etc. based on findings after a gas flow study or CFD. Air Volume - Each ESP is designed to process a certain volume of air with a guarantee performance. Once the volume exceeds the designed amount, the dust collecting efficiency will drop down, leading to unexpected rise in emission. This can be improved by lowering the gas temperature or adding collecting area or doing either an electrical or mechanical upgrade depending on the gas volume increment.

Gas Sneakage - This occurs when the gas passes through non-collection zones, like top suspension area, bottom hopper rim area or the two sides (between the 1st row of CP and ESP wall). Broken or missing DE in whole row also allows the gas to pass untreated. This can be corrected by installing anti-sneak baffles to block these untreated passages.

ISSUE 12

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Troubleshooting - Emission

October - December 2013

Upcoming News

ISSUE 12

Page 8

Taipei Seminar (October 15, 2013)

Tai & Chyun will conduct one-day training seminar on electrostatic precipitator (ESP) operation and maintenance on October 15. The seminar will not only provide basic concept about ESP operation, but also included the Case studies & Experiences from our field engineers, ESP design concept and its efficiency improvement.

(This seminar will be conducted in Chinese)

For more information visit: http://www.taichyun.com.tw/c_content/news/new.htm

Philippines Office:

PCPUG Philippines Last September 26-27, Tai & Chyun participated and made a presentation on ESP Basic and Factors Affecting ESP Efficien-cy during 10th Philippine Coal Plant User Group (PCPUG) Technical Forum at the Sofitel Hotel Philippine Plaza Manila. The event is a local platform to share new ideas on coal han-dling safety, plant performance equipment optimization and plant operating procedures.

Company News

October - December 2013

Contact Information

International Technical Support Numbers:Indonesia Mobile: +62-(0) 811-8160-856Malaysia Mobile: +60-(0)17-472-5119 Thailand Mobile: +66-(0) 898-644-040Taipei Office: 10F, No. 250, Sec. 1, Nei Hu Rd., Taipei, Taiwan Tel: +886-2-8752-5119 Fax: +886-2-8752-5120Manila Office: Unit 203-A Bayview International Tower 1, Roxas Blvd. cor. NAIA Rd., Paranaque CityTel: + 63 2 855 69 87 Fax: + 63 2 822 96 93info@taichyun.com.twwww.taichyun.com.tw

Staff Training:

ICESP India ESP School & Conference At Tai & Chyun we always keep ourselves up to date with new Technology in Electrostatic Precipitator (ESP) area. On September 16 – 21, 2013 our engineer participated in Inter-national Conference on Elec-trostatic Precipitator and ESP School in Bangalore, India.

The ICESP event is organized by ISESP and CPIR, providing an international forum for ex-perts to present and discuss re-cent developments in the field of Electrostatic Precipitation technology.

Conference:

ASIAN SBC USER’S GROUP (01-03 October 2013)

Tai & Chyun held an exhibition in SBC conference 2013 which took place in Penang, Malaysia.

The ASBCUG forum serves as a platform to promote safe handling, storage and usage coals for power plants in Asia. For more information about the conference please visit: www.asiansbcusers.com

Venue: Eastern & Oriental Hotel Penang, Malaysia