BoldEco Environment is affiliated with a worldwide network of companies that provide a variety of air pollution control products and services to virtually every market the world over.
Dedusting/Scrubbing
Spray Cooling Systems
Complete APC Systems
BoldEco Environment has revoked its licenses for the following companies worldwide:
BoldEco Environment designs and builds turnkey air pollution control plants for heavy industry. In the steel industry, BoldEco Environment has furnished new and retrofit gas cleaning plants, whose scope of supply has included fabric filters, heat exchangers, evaporative spray coolers, fans, water-cooled ductwork and other equipment.
Fabric filters can be designed to withstand high negative pressure, high temperatures and high dust loads, such as those found in the operation of steel mill furnaces.
A special filter design is available that promotes uniform airflow distribution to ensure that the dust is well distributed on the collecting surfaces for properly balanced dust extraction and to maintain low pressure drops through the baghouse.
Bags utilized in steel mill Electric Arc Furnace applications can be as long as 8 meters, employing traditional pulse jet technology.
BoldEco have numerous installations where the successful implementation of a spray cooling tower has resulted in capital and operational savings to the customer.
In the case of a new gas cleaning line for an Electric Arc Furnace, our process engineers begin by defining the size of the equipment, starting from customer supplied data (furnace capacity, burner size, coal injection and oxygen flow rates, etc.). From these data, everything from the general layout, to fan and filter capacity, to the size of the water-cooled ducting is defined according to the customer’s specifications. In the past, BoldEco has supplied:
Equipment capacity (process flowsheet)
Calculations, engineering and construction documentation
Combustion chamber and water cooled ducting
Canopy hood dimensions (design for integration with roof)
Doghouse dimensioning and construction
Heat exchangers (natural or forced draft)
Spray cooling chambers
Spark arrestors
Fabric filters (modified reverse air or pulse-jet designs)
Fans and silencers
Stacks and ducting
All ancillary engineering, including electrical, mechanical and structural
By employing our proprietary technology according to our many years of experience, we can cost-effectively provide single-source responsibility for all process engineering and equipment.
The traditional approach to steel mill dust control is to install a pulse-jet fabric filter on the primary gas treatment line. The typical BoldEco approach is to start with a traditional multi-cell pulse-jet filter and modify the concept for ease of maintenance and operational improvement. The first modification is to replace the traditional high velocity module inlet with a low velocity, side mounted settling chamber that acts as a low velocity inlet to all of the pulse-jet modules. Each pulse-jet module is fitted with an advanced design damper for isolation purposes. This design ensures that the gases are introduced into the filtration module at a low velocity in order to facilitate dust drop-out and to eliminate the high velocities in the baghouse module inlet that lead to premature bag failure. In top access pulse-jet designs, the blow pipes can be incorporated into the filter access doors to simplify bag removal and inspection.
BoldEco Environment prides itself on looking inward to its experience base in order to find innovative solutions to a customer’s need. In one case, BoldEco listened to one of its customer’s concerns for the safety of its personnel. This particular customer had a process design that called for a reverse air baghouse running at an air-to-cloth ratio of 3 to 1. The problem was that maintenance personnel would be exposed to dangerous level of contaminants during maintenance procedures because most reverse air baghouse designs necessitate entry into the dirty gas plenum to inspect or change bags.
To resolve this difficulty, BoldEco engineers designed a hybrid reverse-air fabric filter (HRA), that took the low velocity aspect of a reverse air design and applied the top access caged bag design of a pulse-jet. The HRA design not only allowed maintenance personnel to carry out routine and annual maintenance without entering the dirty gas plenum, but because it adopted the caged bag design for the filtration element, a felted bag could be used instead of the woven design limitation of a traditional reverse air baghouse. The felt bag design reduces bleed through and the need for pre-coat of the bags, thereby reducing emissions from the furnace. Among the other considerations is the time required for changing the bags of an HRA collector, which is much faster than that required to change the bags of a traditional reverse air design.
Developed in the late 1980’s, the HRA fabric filter has now been in use for over ten years in numerous applications with no operational limitations. In one EAF application, the HRA filter is installed on an 80 metric ton direct current electric arc furnace, treating almost 700,000 ACFM of gas flow. The total gases are drawn from the furnace and mixed with canopy hood air before introduction into baghouse.
In another HRA application, this time on a blast furnace cast house operation, the filter was chosen due to the difficult nature of the dust, which must be filtered at low velocity to keep the pressure drop at a minimum. Again, this design was chosen in order to avoid entry into the dirty gas/dust plenum and to facilitate maintenance and emergency interventions.
For another customer, in order to provide energy savings, to simplify the air moving system and control, as well as to reduce the quantity of water cooled ducting (and control spark carryover to the baghouse), BoldEco supplied a dual fluid water atomization system to cool the gases from the primary process.
The concept is a simple one. In the place of a high-pressure drop heat exchanger or a long run of water-cooled ducting, an air atomized spray cooler is installed. The purpose of the cooler is to take the gases directly from the spark arrestor / settling chamber and cool them to a temperature that, when mixed with the canopy hood air, will result in a temperature that will not damage polyester bags in the fabric filter. The advantages of this approach are as follows:
Gas pressure requirements similar to those of the canopy hood resulting in lower main fan pressure requirements (smaller fans, lower capital / installed costs)
Lower gas volume to move results in smaller fans and filters
Positive temperature control allows the use of lower cost filter media
Spark carryover control eliminates burned bags
Eliminates long runs of water cooled ducting and water cooling system
Eliminates heat exchangers, high fouling factors and cleaning requirements
Other capabilities include dependable gas analysis for better combustion control, practical doghouse and soundproofing designs, heavy-duty materials handling designs, in-house CFD ducting and flow analysis, as well as other engineering assistance.
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