April - June 2014

Tai & Chyun NewsletterEnhancing Electrostatic Precipitator Performance

What’s new ? Product Feature I Insulator Heater - Purge Air System I Page 1 Case Study I Replacement of Purge Air Heater System I Page 3Troubleshooting I Why Insulator Crack ? And Prevention Method I Page 6ESP Q&A I Water Wash, Electrical Setting, Realign Bending CP, etc.I Page 7News & More about us... I Page 8

ISSUE

14

Insulator Heater Purge Air System

Product Feature

April - June 2014

Purge Air System

Are you always bothered by the ESP operation problem caused by insulator failure? Have you ever thought that using the right heating system can help extend the life of your insulator as well as keep the maintenance cost to the minimum?

We know that most of the ESP heaters only have the function of heat generation. The main difference of the purge air heater from the other ESP heaters is that it does not only provide hot air to preheat insulator compartments, but also blow the hot air into the insulator compartment, thereby purging dust within the insulator.

The purge air heater is a combination of heater and air blower. It generates and provides high temperature air flow to the insulator compartment in order to prevent the immediate change of the insulator temperature when ESP is put into operation. It also maintains positive pressure inside the chamber which can prevent dust from going up through the HV insulators. The heater generates the hot air and the blower pushes the air flow through the heater, passing through hot air duct and is delivered to insulator compartment.

Purge air heater reduces dust build up on insulator that can prevent electrical tracking on insulator surface and insulator failure often caused by moisture and dirt. Moreover, purge air heater can also help eliminate localized sparking, reduce humidity level and lower corrosion factors in ESP internal component.

Advantages of Purge Air Heater:

Short preheating timePurge air heater requires only two to four hours before ESP start up to ensure that temperature and moisture inside insulator compartment is in a proper level.

Protection of insulatorThe purge air heater not only generates heat, but also helps maintain clean insulator surface.

Convenient inspection and maintenanceIt can be inspected and fixed during ESP operation. No shutdown is required for its maintenance.

Minimized inspection timeMoreover, the inspection period can be kept to minimum since it is only one stop checking. It is not necessary to open all insulator compartments for checking one by one.

To sum up, the purge air heater is used to protect the insulator from sparking or arcing due to dust accumulation and also to keep the insulator clean and dry. We at Tai & Chyun can use our experiences to help you choose the most accurate specification and the most suitable purge air heater system.

Product Feature

April - July 2014April - July 2014April - July 2014

ISSUE 14

Page 2

Purge Air Heater System Replacement

Application

Purge air heater system of a boiler ESP installed in a petrochemical plant situated in Thailand

Problem

1. Corrosion was observed all around the purge air heater.

2. The wiring system was also damaged and heavily corroded.

3. The expansion joint joining fan blower and heater box was also damaged. 4. The control panel for purge air heater system on top of the ESP is heavily corroded and some parts are already not functioning.

Case Study

Heavily Corroded Purge Air Blower

Heavily Corroded Purge Air Heater

April - June 2014

Solution

Purge air heater system was renewed during maintenance outage. A more compact and smaller sized purge air system was supplied by Tai & Chyun. As the size of the purge air system was different, the structure base, wiring route and air duct were modified to suit the new system. The control panel was repaired and the broken thermostat in the control panel was changed.

Benefits

After installation, the purge air heater was tested and the result was satisfying. The functioning purge air system can keep the insulators at the suitable operating temperature and thereby prevent the insulators from cracking. It also keeps the insulator compartment free from the dust build up and moisture, thus minimizing the risk of sparking and arcing, leading to a stable ESP operation.

Case Study - Purge Air System Replacement

ISSUE 14

Page 4

Heater Duct With Cladding

The New Purge Air System

Testing

Before

Before

Before

After

After

After

After

Insulator Crack & Prevention Method

Troubleshooting

“In an ESP operation, the main function of an insulator is to electrically isolate discharge electrode from collecting electrode and grounded ESP due to high voltage current. Failure of an insulator can cause grounding and other ESP operational problems. The most commonly found insulator failure is the crack of the insulator. In this edition, we will talk about the causes of insulator cracks and the prevention methods.”

April - June 2014

Insulator Crack and Prevention Method

Let’s start with the causes of the crack of insulators. The chief cause of cracking of insulator is thermal shock due to the different temperature at the inner and outer surface of the insulator. Other causes are: DE frame misalignment, improper installation, heater failure, dead lock on DE rapping shaft and dust buildup inside the insulator compartment causing electrical shocks and crack down.

1. Uneven loading: DE frame imbalance may lead to the unbalanced weights on each insulator and thereby the crack of the support insulator. Improper installation and misalignment will lead to the cracking.

2. Electrical shock on the surface of the insulator: Moisture condensation caused by in-leakage at the compartment, heater failure or blower failure that may encourage sparking and tracking on the insulator.

3. Dust tends to buildup on the inner and outer surface of the insulator if it has not been cleaned for long, or if the blower filter is broken.

4. Dead lock on shaft: Rapping shaft gets stuck and cannot rotate while the motor is still running, which leads to the crack and damaged rapping insulator.

5. Different temperature at the inner and outer surface of the insulator: May lead to thermal shock of the insulators.

After getting to know the main causes of the cracking of insulator, let’s move on to the maintenance and prevention of the insulator failure. Some of the regular maintenance know-hows of the insulators are as follows:

1. Conduct regular check up on the insulators and heaters during shutdown period. 2. Keep the inner and outer surface dry and clean. 3. Use dry cloth and 70% alcohol for the cleaning of dusty insulators. 4. Replace the broken insulators with new one. 5. Check DE frame balance and alignment after insulator replacement. 6. Make sure all heaters/blowers are working properly. 7. Turn on the heaters around 8 hours before start up. 8. Ensure that all insulators are dry and clean before start up.

Other than above mentioned methods, the installation of purge air system is an effective remedy as it can protect and keep the insulator clean, dry and prevent the sparking and arcing due to dust accumulation. It blows hot air to insulator chamber, thereby preventing moisture and dust accumulation which in turn prevents sparking and arcing. It also prevents insulator damage due to thermal stress or temperature difference between the inner and outer surface.

For more information, please feel free to contact our sales representative and the technical team or log on to www.taichyun.com.tw.

ISSUE 14

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Troubleshooting - Dust Buildup

Support Insulator Crack

Surface Cleaning

Ring Heater

Insulator & Maintenance:

Inner Surface Cleaning

April - June 2014

ESP Q&A Session

ISSUE 14

Page 7

Question: What condition is proper for water wash? Among 4 ESP cleaning methods which one is the most effective? Answer: It depends on the characteristic of dust; mostly all ESP can apply the water wash except in Cement plant and recovery boiler in Pulp mill. The important part in water wash is to make sure that the ESP is completely dry before startup. Manual cleaning is the easiest way for internal parts and still effective to dislodge the dust build up in the ESP (but the dusty working environment to workers is a main concern as well as the doubt on cleaning thoroughness).

Question: Which setting is better for Field 1, 2, and 3? (80%, 65%, and 45%) or (40%, 50%, and 80%)? Answer: Secondary voltage (kV) setting depends on the mechanical conditions of the ESP. Settings can be set to maximum if the mechanical condition is very good. Secondary voltage limit settings can be gradually increased as long as no spark is detected. By assuming, these mA limits are set by the plant due to the suspicious mechanical condition. Generally, the inlet takes heavy dust loading thus being suppressed to lower output level while the outlet is dealing with less dust but finer grain to be caught – so the 40%- 50%-80% seems to be a better choice.

Question: What is the best practice to realign bent Collecting Plate (CP) ? Answer: It depends on how severe the bending is. If the CP is bent seriously from top to bottom and the middle is so close to CP frame then there is no way to realign or correct this problem. If some section of the CP is bent then we can use gas torch to heat up the bent section enabling it to bend back to its better shape. However, this action has no assurance that the heat treated CP could be properly restored with the difficulty of flame temperature/timing control.

Question: Please identify why dust heavily stick on top of collection plate and please suggest how to solve the problem? Answer: It could be the vibration created by rapping system is not enough to dislodge the dust on the upper section of collecting plate. There are some problems also that make the dust build up on the upper section such as water leakage. Further assessment and evaluation should be done on the dust build up.

* Question asked in previous seminar

Free

Don’t miss special gifts from Taiwan!

We would like to introduce a Q&A session. Our engineers are ready to answer related questions for ESP user. You can also be part of us by sending in questions about your ESP or share with us your experiences in ESP trouble shooting. If your question gets published in the next quarter newsletter, we will send you a special gift from Taiwan!

How to send in ESP question: You can send question in your local language by contact T&C sales representative!

Or mail to info@taichyun.com.tw by setting the subject as: “Newsletter Marketing Activities” As well as providing your name, company name, address and contact number

Gift

Upcoming & Company News

April - June 2014

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 93Bangkok Office: Na Nakorn Building: No.99/349 Chaengwattana Road,Thungsonghong, Laksi, Bangkok 10210, ThailandTel: + 668-9-900-7825 Website: www.taichyun.com.twEmail: info@taichyun.com.tw

Malaysia: Electrostatic Precipitator Seminar

Date: April 10, 2014 (Thursday)Location: Armada Petaling Jaya Hotel, Malaysia

Tai & Chyun will once again conduct a one-day training seminar on Electrostatic Precipitator. Our engineers are ready to answer your questions about ESP operation problem as well as sharing their experiences with end-user.

What will you learn from our ESP seminar? • Complete set of ESP basic operation• How to maximize ESP efficiency• ESP troubleshooting, prevention and point of attention • Shutdown & Start up procedure • Safety knowledge when working with ESP

Partial list of previous participants:• Lafarge Cement • Kapar Energy • Tasek Corporation • Negeri Sembilan Cement • TNB Janamanjung • YTL Cement

Upcoming News:

Venue: Sirikit Convention Center – Bangkok Booth: No. 2Date: 23-25 April, 2014

An Exhibition on Equipments, Machineries, Chemicals, Services and Supplies for Pulp, Paper, Board and Tissue Production

We are ready to share our knowledge about ESP technology in Pulp & Paper Industry. Please come and drop by our booth, our engineers and staff will be happy to discuss with you regarding your ESP questions and concerns.