What is a Baghouse

regenerative thermal oxidizers

A fabric filter, commonly referred to as a baghouse, is a dust collection device designed to separate particulate from process gases and collect material so it can be easily handled. Dustex™ baghouses are capable of filtering out particle sizes PM10, PM5, and PM2.5.

Baghouses are utilized in many industrial applications such as carbon black, cement, insulation manufacturing, lime, metals and mining, and power.

Baghouses are the most commonly used for dust collection in hot and dry processes. This type of filter technology is one of the oldest and the most common form of filtration equipment in the world, with literally hundreds of thousands of installations. Fabric filters come in all sizes ranging from small bin vent collectors that collect a few thousand cubic feet per minute (cfm) to very large dust collectors that can handle over two million cfm of gas. They are superior to other particulate collection technologies due to their high efficiency, low maintenance, and cost-effectiveness. Today’s modern baghouse is designed around the pulse jet concept whereby a pulse of air is sent into the clean side of the bag to shake/pulse the collected dust from the bag.

A baghouse contains filter bags, also known as filter media. A metal cage is placed in each bag to support the bag so that it does not collapse on itself under negative pressure. These filter bags are arranged in rows and hung vertically from the tubesheet. The tubesheet is a sheet of metal at the top of the baghouse with an array of holes in which filter bags are installed. Bags are designed in many different types of fabric and finishes depending on the type of particulate, the temperature of the gases entering the baghouse, and the gas constituents. Particulate is captured on the outside of the filter bag, clean air passes through the bag, up the center, and out to the exhaust. Over time a dust cake develops on the media surface and one of several types of cleaning systems removes the dust from the filter media.

regenerative thermal oxidizers

The Dustex™ Baghouse Cleaning System

How It Works

destruction of VOCs and HAPs

The dirty gas stream enters the baghouse either via an inlet air plenum or directly into the hopper. Upon entry, the larger particulate matter drops directly into the hopper below due to gravity. As the gas flows upward into the filter bag array, the finer particles collect on the outside of the filter bags, allowing only the clean air to pass through the filter media, into the clean air plenum, and then released into the environment.

Once a layer of dust cake is built on the outside of the filter bags, bag cleaning takes place to regenerate the permeability of the filter media. The dust cake being built up on the surface of the bags adds to the filtration efficiency of the system but also increases differential pressure over the filter system resulting in higher energy consumption. Once the differential pressure reaches a high set point, cleaning is started until the differential pressure reaches a low set point, and the process is repeated.

destruction of VOCs and HAPs

The side-entry inlet design is a current innovation that allows for maximized flow distribution and elimination of can velocity by using inlet baffling array. The crossflow arrangement minimizes bag wear. This true crossflow design is far superior to hopper entry designs, in that it also reduces re‐entrainment and aids in cleaning efficiency. Additionally, the Dustex™ high volume intermediate pressure cleaning system is engineered specifically for long bag pulse‐jet system applications. This design is not a “typical hopper entry” baghouse design and is proven to perform exceptionally well in multiple installations.

The picture below shows the CFD model comparison of a Dustex™ side entry design vs. a typical hopper entry. As shown in the picture on the left, the side entry design velocities are lower, and most of the flue gas passes from the front wall to the rear wall of the module. In the hopper entry, as shown in the picture on the right, the flue gas velocities are much higher, and the flue gas travels vertically upward to the bags. These characteristics of hopper entry designs lead to bag abrasion and re‐entrainment of particulates back onto the bags.

destruction of VOCs and HAPs

Dustex™ Pulse-Jet Fabric Filter Features

  • DustexTM Monolithic Floating Pan Top Door
  • Capable of long bag design up to 30′
  • Proprietary, advanced side-entry inlet design
  • Shop insulation and cladding
  • Side inlet design where air flows into the side of module and across bags
  • Best choice for high dust loading or low bulk density material applications
  • Split modular or panelized designs
  • Penthouse or walk-in plenum
destruction of VOCs and HAPs

Dustex™ Pulse-Jet Fabric Filter

The pulse-jet type fabric filter is the leader of the baghouse technologies. With no moving parts in the basic design and removal efficiencies of greater than 99%, a pulse-jet baghouse can be designed to meet the available footprint for the plant along with the most cost-effective and efficient design for the operation.

With the Dustex™ Pulse-Jet Fabric Filter, dirty gases enter the baghouse modules through a side inlet of the baghouse and are evenly distributed throughout the filter media.

The pulse-jet cleaning cycle is controlled by a solid-state timer that controls the pulses of the compressed air. Compressed air stored in an air header is released by a solenoid actuated pulse valve and travels from the blow pipes that are mounted above each row of the filer bags into the bags creating a pressure wave. This pulsed air travels down the length of each filter bag in a row, causing a ripple effect, thereby loosening and releasing the dust cake into the hopper.

With the pulse-jet cleaning system a plant operation can choose to clean the filters on-line or off-line. With the ability to program the system for dust removal on a regular and/or on-demand interval, this technology allows for more complete cleaning and reconditioning of the filter bags with minimal pressure fluctuations to the process.

The area above the tubesheet, known as the clean air plenum, serves as the outlet to carry the clean air into the atmosphere. Part of the cleaning system – the blowpipes, are also housed in the clean air plenum. Air headers with solenoid valves sit on top of the clean air plenum. The tube sheet is located below the blow pipes and holds the filter bags in place.

After the gasses pass though the filter, the particulate is collected on the bags and gathered in the hoppers which feed the material handling system. The clean gases then pass through the outlet manifold, ID fan, and stack.

Dustex™ Floating Pan Top Door

The Dustex™ monolithic lift‐off top door has been very well received in the various industrial applications for several reasons:

  • Elimination of confined space entry – Maintenance personnel simply step down onto the tubesheet to access bags via removal of this lift-off door inside a penthouse.
  • Reduction of clean air plenum surface area for radiant cooling and subsequent acid gas condensation and corrosion.
  • Immediate access for bag maintenance – Integral cleaning system that lifts with the top lids and allows immediate access to the tubesheet, bags and cages for maintenance.
  • Prevention of false air into the system leading to a more efficient system and less energy waste.

The cleaning system consists of double diaphragm valves connected to the blowpipes and mounted over the bags. Cleaning can occur at regular intervals based on a timer or can be dependent upon baghouse differential pressure. As differential pressure reaches a high limit, cleaning is started and continues until the differential pressure is returned to a low limit. A thin dust cake remains on the bag for further, more efficient filtration. The clean air exits the baghouse via the clean air plenum and is released into the atmosphere.

RTO fast acting poppet-style diverter valves
RTO fast acting poppet-style diverter valves

Benefits of a DustexTM Baghouse

  • Efficient on-line cleaning at high air-to-cloth ratios
  • Reduces bag abrasion issues
  • Reduces particulate re-entrainment
  • Highly efficient at high dust loads
  • DustexTM Monolithic Floating Pan Top Door design
    • Ease of entry
    • No warping or leaking
    • Easy bag changeouts
    • One mechanical connection required (single compressed air connection)
    • One electrical connection
    • Penthouse design allows for:
      • No confined space entry permit/procedure
      • Storage and staging of bags and cages
  • LDX modular design
    • Reduces field welding requirements
    • Reduces erection time
    • Eliminates most scaffolding requirements
  • Baghouse Research and Development – we continue to perform internal testing, logging, and refining performance to ensure optimum efficiency in the field.

Industries Served

We serve all industries ranging from the food industry to the lead acid battery recycling industry. Note that if your industry is not listed here, we can provide a solution for your operation. Experience for over 70 years helps us be confident that we can provide our customers with a cost-effective solution without sacrificing performance.

  • Aggregate
  • Aluminum
  • Ammunition
  • Biomass
  • Brick
  • Building Materials
  • Calciner
  • Carbon Black
  • Cement
  • Copper
  • Corn Processing
  • Diesel Fume
  • Fertilizer
  • Iron
  • Lead
  • Mineral Wool
  • Oil & Gas
  • Pharmaceuticals
  • Power
  • Pulp & Paper
  • Steel
  • Aggregate
  • Aluminum
  • Ammunition
  • Biomass
  • Brick
  • Building Materials
  • Calciner
  • Carbon Black
  • Cement
  • Copper
  • Corn Processing
  • Diesel Fume
  • Fertilizer
  • Iron
  • Lead
  • Mineral Wool
  • Oil & Gas
  • Pharmaceuticals
  • Power
  • Pulp & Paper
  • Steel

Controlled Pollutants of a Baghouse

Baghouse Literature Library

Have other needs? LDX Solutions can be your one source and address all your Air Pollution Control needs. Many of our customers need support with material handling and waste. LDX Solutions can provide gathering screws, waste silos, etc. to maintain compliance and be fully operational.

Today, fabric filter technology is often prescribed as part of a solution for a plant process that not only has particulate matter in its process but may also have a need for dry scrubbing and absorption systems to control acid gases (SOx, HCl, HF), mercury, heavy metals, NOx, and gas temperatures.