Re: Active Carbon Pneumatic Transport
Roots blower is very normal for lean phase conveying.
Since this is some sort of injection system using only
160kg/h system pressure losses will be very low,
you can also look at fan conveying i.e. side channel
blower. ■
Re: Active Carbon Pneumatic Transport
A Roots type positive displacement blower is preferred because it has the best operating characteristics for dilute phase pneumatic conveying. A slight change in operating pressure will result in only a small change in air flow rate. Side channel blowers are not as good but as your system pressure drop will be relatively low they should be OK for the duty and probably cheaper. Fans have very much poorer operating characteristics and I would avoid these, particularly with a 250 m long pipeline. ■
Re: Active Carbon Pneumatic Transport
Dear Mr pablocini,
Although the rate is relatively low, the distance is not (260m) and the pipe bore is only 3 inches.
as we are not aware of the compressor size, it is not possible to estimate the pressure drop, unless you already know them both.
regarding the compressor type to be applied, the following list:
Types of convey air compressors
Roots type blower
-high volumes-/-900 m^3/min
-pressure0,5-/-0,8 bar
-vacuum0,5-/-0,6 bar
-/-,85 bar (with pre inlets)
-oil free
-isochoric compression(high power demand for high
pressure ratio)
-mainly used in low vacuum installations(low energy consumption per ton
due to the efficiency of the
pneumatic system and the low
power demand at partial load)
-used in high vacuum installations with pre inlets
Screwcompressor
-volumes-/-250 m^3/min
-pressure-/-3,5 bar
-vacuum-/-0,7 bar
-/-,85 bar (with pre inlets)
-oil free
-internal adiabatic compression followed by isochoric expansion or compression
-used in high vacuum installations with pre inlets
-mainly used in pressure discharge systems
Oil-filled screw compressor
-volumes-/-100 m^3/min
-pressure-/-6,0 bar -/- 10 bar
-vacuum-/-not used
-not oil free
-oil separators
-inlet closes at set minimum and maximum discharge pressure
-internal adiabatic compression followed by throttled expansion or isochoric compression
-used in pressure discharge systems with pressure reducer.
-rental units available as replacement for a broken compressor or as additional booster.
Vane compressor
-volumes-/-100 m^3/min
-pressure-/-2,5 bar
-vacuum-/-0,6 bar
-not oil free
-oil lubricated vanes
-inlet closes at set maximum discharge pressure
-internal adiabatic/isothermic compression followed by isochoric expansion or compression
-used in vacuum systems
-used in pressure discharge systems.
Piston compressors
-volumes-/-80 m^3/min (double acting)
-pressure-/-4,0 bar (single stage)
-vacuum-/-0,65 bar
-not oil free
-lubricated pistons
-inlet closes at set maximum discharge pressure
-internal adiabatic/isothermic compression to delivery pressure
-used in pressure discharge systems.
-low power demand.
Turbo compressors
-volumes-/-750 m^3/min
-pressure-/-5,0 bar
-vacuum-/-0,5 bar
-oil free
-diffuser vane control
-internal adiabatic compression
-used in low vacuum systems
-used in pressure discharge systems.
-complicated installation
-high energy demand
-expensive.
Water-ring compressor
-volumes-/-200 m^3/min
-vacuum-/-0,75 bar
-moisture to atmosphere
-internal adiabatic compression
-used in vacuum systems
-auxiliary equipment : water pump
-very high energy demand over full range.
success
teus ■
Teus
Question
jJUST GUESSING YOU ARE ABSORVING SULFUR AND DIOXINES
DILUTING THE aCTIVATED CARBON WITH LIMESTONE WILL ENHANSE ITS STABILITY ONCE SATURATED , HOW DO YOU ASSES WHEN YOUR ACTIVATED CARBON IS SATURATED? ■
Re: Active Carbon Pneumatic Transport
Marco,
we are injecting the active carbon in a flue gas duct for the adsorption of dioxines. After that, we will collect the active carbon, together with the rest of dust dragged by the gas, in an electrostatic precipitator. We are making some analysis of the dust collected in the hoppers of our ESP in order to know the maximum allowable limit of carbon content in that dust (we estimate that it will be around 20%). The limestone or any other inert material (together with the rest of collected dust) will be used to dilute the carbon in the hopper's dust in order to keep the carbon content always below that limit.
Regards ■
Re: Active Carbon Pneumatic Transport
let me see if I understood well.
You are injecting the AC in the flue gases stream then it will be collected together with the flue gas dust in the ESP ?
So the Dioxines will be collected during pneumatic transport? or maybe some dioxines will be colected in the electrostatic precipitator?
Do you have measured the saturation of the AC or the Exaust composition? to evaluate your decont efficiency?
Have you ever had self ignition on your AC?
Regards
marco ■
Re: Active Carbon Pneumatic Transport
Marco,
we are developing this project for a sinter plant. During the sintering process the temperature range needed for the dioxin generation is achieved. This dioxines are dragged together with the fumes created during the process and they are driven through a big main duct (5 m diameter) to an ESP and finally to the stack. The problem is that the ESP is not able to collect the dioxines when they are alone; that´s the reason of injecting active coal in the main duct. This is a good adsorbent for the dioxines, so the dioxines are collected by the active coal inside the duct before they arrive to the ESP. Once they are together (dioxines trapped inside the carbon) the ESP is able to collect them.
The flue gas flow through the gas is around 800000 Nm3/h, and for that value the estimated necessities of active carbon are around 60 kg/h (according to the carbon supplier). Regarding the limestone, we are only using it for inertizing the active coal once that is collected in the ESP hoppers. The carbon content in the dust collected in the hoppers can not be higher than 20% (at the end in the hopper we will have the normal dust generated in the process, the active carbon dust and the limestone that we are adding. The carbon can not be more than 20% in this mixture). We still are not working with the system; according the references we have we shoulden´t have any problem, but we are a little bit concerned about the existing ignition risk so we will take a lot of safety measures.
By the other hand,I have another different question:
The silos that we will use for the storage of carbon and limestone have the following dimensions:
Capacity: 120 m3
Diameter: 4500 mm
Bottom cone slope: 56º
we will provide them with aeration or fluidization in the bottom and I would like to ask you for some recommendations regarding this issue: ■
Re: Active Carbon Pneumatic Transport
Sorry, I did something wrong in the last post, this is the final part of it:
By the other hand,I have another different question:
The silos that we will use for the storage of carbon and limestone have the following dimensions:
Capacity: 120 m3
Diameter: 4500 mm
Bottom cone slope: 56º
we will provide them with aeration or fluidization in the bottom and I would like to ask you for some recommendations regarding this issue:
- Reccomended air pressure for fluidizing
- Recommended air flow for fluidizing
- Any other recommendation for silo aeration
Regards ■
Active carbon Pneumatic Transport
Hi everybody,
we are developing a project that involves a pneumatic transport with the following characteristics:
Conveyed Material:
A mixture of Powder Active Carbon and Limestone
Powder Active Carbon
- Particle Size: 0.015 - 0.025 mm
- Density : 550 kg/m3
- Dosing rate of material: 60 kg/h
Limestone:
- Particle Size: 0.1 - 0.5 mm
- Density : 1800 kg/m3
- Dosing rate of material: 100 kg/h
Conveying distance:
- Horizontal: 250 m
- Vertical: 10 m
- Number of bends: 5 (90º) + 2 (120º)
Pipe size: DN 80
The company that is designing the pneumatic transport is suggesting the installation of a Root Blower type for this purpose. What are the advantages and disadvantages of using this type of blower? Is this the most suitable equipment for this case? Any other recommendation regarding this pneumatic transport?
Best regards ■