Installation

Depending on the baghouse chosen, installation and initial operation startup may take from a
few days to a few months. In any case, proper installation procedures will save time and
money and will also help in future operation and maintenance of the baghouse.
Good coordination between the baghouse designer and the installation and maintenance personnel
will help keep the baghouse running smoothly for years. Occasionally this coordination
is overlooked. The baghouse is installed, turned on, and forgotten about until it stops working
completely. By then it may be too late to keep the unit going, and the baghouse may have to be
rebuilt or even scrapped. Some key features for the facility operator to evaluate during the
installation period are listed here:

• Easy access to all potential maintenance areas - fans, motors, conveyors, discharge valves,
dampers, pressure and temperature monitors, and bags
• Easy access to all inspection and test areas - stack testing ports and continuous emission
monitors (opacity monitors)
• Weather conditions - the baghouse must be able to withstand inclement weather such as
rain or snow

The following features have been suggested for a properly designed and installed baghouse
(McKenna and Greiner 1982):

1. Uniform air and dust distribution to all filters. Duct design, turning vanes, and deflection plates all contribute to uniform gas distribution. Often, this equipment arrives loose and is field-installed. If improperly installed, it can induce high airflow regions that will abrade the duct or bag filters or cause reentrainment and induce high-dust-concentration regions that can produce uneven hopper loading and uneven filter bag dust cake. 
2. Total seal of systemfromdust pickup to stack outlet. Inleakage of air at flanges or collector access points either adds additional airflow to be processed or short-circuits the process gases. Inleakage to a high-temperature system is extremely damaging, as it creates cold spots and can lead to dew point excursions (gas temperature falls below the dew point) and corrosion. If severe, it can cause the entire process gas temperature to pass through the dew point and result in condensate on the bags. Early bag failure and high pressure drop will generally result. The best check for leaks is for the installation technician to inspect the walls from inside the system during daylight. Light penetration from outside isolates the problem areas. It is particularly important to seal the dust discharge points in negative systems. Inleakage here will result in incomplete or no discharge, which can lead to reentrainment problems, yielding high pressure drop and hopper fires. 
3. Effective coatings and paint. Most systems are painted on the exterior surfaces only. Extra care should be taken to touch up damaged areas with a good primer and if equipment is not delivered finish-painted, apply it as soon as possible following erection. Unprotected primers allow corrosion to occur and require sandblasting and costly repairs for the facility operators. If the system has been internally protected with a coating, it should be thoroughly inspected for cracks and chips, particularly in corners, and repaired before operation begins. A poor interior coating can be worse than none at all because it will trap corrosive elements between the coating and the surface it was intended to protect. 
4. Properly installed filter bags. The filter bags are the heart of any fabric filter collection system. Improper installation can result in early bag failure, loss of cleaning effectiveness, and thus high pressure drop and operating costs or increased stack emission. Each manufacturer provides instructions on the proper filter bag installation and tensioning (where required). These must be explicitly followed. Very often, early bag failures can be traced to improper installation. It is much easier for the installation technicians to check and recheck bag connections, tensioning, locations, and so on, in a clean, cool, dry collector than it will be one day after startup. Bag maintenance usually accounts for 70% of annual maintenance time and money. Extra efforts in this area during installation can have a significant effect. 
5. Proper insulation installation. Insulation is typically used to prevent O&M problems on high-temperature collector systems. When handling high-temperature gases, it is important to maintain the temperature of the gas and all collector components coming in contact with it above the gas dew point. Much of the time, all or a part of the insulation is fieldinstalled. The installers should check to see that all surfaces and areas of potential heat loss are adequately covered. In particular, they should check to see that field flashing also has insulation beneath it. Cold spots cause local corrosion. Gross heat loss may cause excessive warm-up time or lower the gas temperature below the dew point. 
6. Total seal between dirty side and clean side of collector. Remember, the primary purpose of the dust collector is to separate the particulate matter from the gas by means of fabric filtration. This means that all the gas must pass through the fabric. Any leaks bypassing the fabric filters will directly emit dust to the stack and therefore reduce the collection efficiency of the system. The time to inspect "bypass leaks" is before startup, when everything is clean and accessible. The best technique is to use a bright light on one side of the plenum and visually observe for light penetration on the other. This is the most effective in total darkness. The installers should take extra time to check this important area. Tracking down stack emissions not associated with bag failures can be extremely difficult after startup.
7. Properly installed and operating dampers. Most systems employ several dampers to isolate areas of the system or control the volume of air flow. Proper alignment of both internal blades and the operating linkage is important. In high-temperature applications, special care must be taken to allow for proper operation and sealing at the operating temperatures. Some dampers may require readjusting after reaching high-temperature operation. In modular systems, single modules are normally isolated for bag cleaning and maintenance. Leakage through these isolation dampers can cause improper bag cleaning. It will also create a very poor ambient condition for maintenance workers to work in. This, in some applications, can pose a health hazard, and in all applications results in lower-quality workmanship or incomplete maintenance. 
8. Properly operating mechanical components. Most mechanical components are designed with a normal operating direction. Cylinder rod location, motor rotation, and so on, must be checked. Remember, when hooking up an AC motor, the installer has a 50% chance of being correct on the first try. Not only will a backward-moving conveyor produce no discharge, but it can pack material so tightly that it bends the screw. Left uncorrected, a reversed screw conveyor will result in a full hopper. The industry abounds with horror stories where full hoppers have led to burned bags, or dust that has set up, requiring jackhammers to remove it.
9. Smoothly running fans. Fans must be checked for proper rotation, drive component alignments, and vibration. Fans should be securely mounted to a sufficient mass to prevent excessive vibration.
10. Clean, dry compressed air.Most systems employ compressed air to operate dampers, controls, instruments, and so on. Probably more systems suffer shutdowns and maintenance problems due to poor-quality compressed air than for any other reason. Clean, dry air is necessary to maintain proper operation of the pneumatic components. In installations where the ambient temperature drops below 32°F, a desiccant dryer system is generally employed. Sometimes, insulation of air lines and pneumatic components will be required. Often, these considerations are not included in the dust collector system, with "clean, dry compressed air to be supplied by the owner." Remember the air must be clean and dry when it reaches the pneumatic component.

Each baghouse installation should have its own checklist reflecting the unique construction components of the unit. The installation crew should prepare a checklist before beginning the final inspection and initial startup. Table 1 shows an example of a typical inspection and startup checklist. This checklist would be useful for the facility engineer to make sure that the baghouse is properly installed.

                                          Table 1. Inspection and startup checklist

Installation errors can have a disastrous effect on the operation and maintenance of the baghouse.
Typical installation errors and their effect on O&M are given in Table 2.

                         Table 2. Typical installation errors and their effects on O&M