Product category:
Powder, droplet and particle characterisation
News Release from: Hosokawa Micron | Subject: Activated carbon
Edited by the Processingtalk Editorial
Team on 14 January 2004
Olive stone grinding to produce
activated carbon
One of the world's leading producers of activated carbon has installed a complete turnkey milling and process control system from Hosokawa Micron to give them unmanned production 24/7
One of the world's leading producers of activated carbon has installed a complete turnkey milling and process control system from Hosokawa Micron to give them unmanned production 24 hours a day, seven days a week Grinding olive stones prior to processing into activated carbon, the system produces an olive stone flour with 100 percent consistent particle size below 150microns
This article was originally published on Processingtalk on 13 Nov 2003 at 8.00am (UK)
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As Ian Haggan of Hosokawa Micron explains, "Activated carbon is a microporous carbonaceous material which is produced from various raw materials such as peat, wood, lignite, anthracite, fruit pips or shells.
The raw materials are converted into activated carbon using steam (temperature above 9000C) or acid (temperature above 4500C).
The activation process creates pores in the carbon, whose surface may exceed 1500m2/g.
Further reading
Isolator technology for wet chemical synthesis
Companies operating in the wet processing field of chemical synthesis now have access to innovative barrier containment systems when safeguarding personnel from potentially hazardous substances
New Hosokawa Micron wet grinding mills
The Alpine ANR Wet Agitated Pearl Mill is designed for the large scale ultrafine wet grinding of medium to hard materials where the downstream process can accept a fine wet product
Mixer for coating, heating or cooling applications
For fine layer coating of individual particles, the highly intensive continuous mixing action of the Hosokawa Turbulizer offers the ideal coating solution.
It is by far the most important adsorptive media due to its wide range of pore sizes.
This adsorptive process is used extensively for the removal of unwanted colours, odours or tastes, contaminants, or hazardous elements from process materials.
It is involved in the production of almost every product containing sugar or sweeteners to guarantee a pure end product.
It has a vital function in the purification of pharmaceuticals, and is also used in some dialysis apparatus to purify the blood of patients suffering from kidney failure.
The importance of surface area is paramount in the efficiency of this process.
Therefore the need for efficient milling and grinding of the material is of equal importance.
Activated carbon products possess the ability to prevent vapours from all kinds of devices escaping into the air which is why many ELCD (Evaporative Loss Control Devices) fitted to many automobiles contain an activated carbon filter which absorbs the petrol vapours that would otherwise escape through the petrol tank vent.
The complete system is controlled by a SCADA package linking back into the customer's master control system, providing management with routine and detailed reports of system status on all the key aspect of the system.
Part of the control system is concerned with trend analysis of the specific parameters that will assist in process troubleshooting and any corrective maintenance action required.
The plant consists of a mixture of Hosokawa brand name equipment and OEM equipment mainly used to transport material from the feed vehicles to the milled product's final destination.
This comprises an electromechanical en-masse feeder, screw feeder, rotary valves, lean phase conveying and dense phase conveying to storage silo.
Processing of the olive stone granules (4-6mm diameter) into fine olive stone flour commences with the transportation of granules from a moving floor box discharge device via a screw conveyor into an en-masse mechanical conveying system.
This maintains an optimum amount of material within the feed material reception hopper, feeding material only when the hopper reaches a certain low weight level.
The hopper, fitted with a displaced air vent filter, is positioned on load cells feeding weight data back to the central control facility.
A manual slide valve is fitted to the discharge point on the hopper.
The feed control to the mill is via a screw conveyor fitted with a variable speed motor controlled by a frequency converter.
Feed material is then discharge under gravity through a metal detection system which removes any tramp material from the olive stone feedstock.
Material is then introduced into the pneumatic by-pass of the Hosokawa Mikro ACM 150 Air Classifier Mill via a rotary valve.
The material entering the grinding chamber is aggressively comminuted by the action of the hammers on the grinding track.
The fine material rises up on the air stream and is presented to the classifier.
In-specification material passes through the separating device to be conveyed onwards.
Control of particle size is affected by the classifier speed, which is controlled by a variable speed motor and frequency converter.
Oversize material drops back into the grinding area for further size reduction and classification.
The acceptable milled material is conveyed upwards and collected on the filter bags of the reverse jet filter and is released by the sequential pulsing of the bag sets.
The differential pressure between the clean and dirty sides of the system is continually carried out to identify any process problems relating to bag efficiency.
The collected product is discharged from the filter hopper by means of a constant speed rotary valve.
The milled material falls under gravity on a vibratory safety sieve, whose task it is to remove spurious oversize grits.
The in-specification material discharges into an intermediate hopper fitted with level probes, which monitor material levels.
The milled material is finally dense phase conveyed to an existing storage silo.
All ductwork for the system was provided by Hosokawa Micron within the scope of supply from the air inlet section to the dense conveying line to the storage silo as was the steel framework supporting the system and all system lighting.
The electrical installation for the services and the plant as a whole was engineered and installed by Hosokawa Micron Ltd.
The system was supplied with all the necessary instruments and valves to meet the process duty and the customer's requirement for control and data acquisition system and was designed to meet all prevailing safety standards.
The software philosophy is based on a multi-page screen format allowing the plant operator to monitor the plant in overview mode during normal operation.
Only when alarm conditions apply or process changes are required is it necessary to magnify the detail on the screen format.
All the major system parameters are datalogged and statistically trended.
These trends provide valuable data to assist in process problem solving when required.
The Hosokawa Micron technical team commissioned the system with final de-bugging, functional testing and material runs to meet the process guarantee.
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