Activated Carbon Market – Tariff Update
Duty is in the Eyes of the Beholder

By Ken Schaeffer

The final tariff rates for steam activated carbon imported into the US from China were announced by the Department of Commerce (DOC) in February 2007 and the International Trade Commission (ITC) voted unanimously to affirm the new tariff rates in March 2007. The tariff is for an initial five-year period and subject to renewal. The new tariff does not cover activated carbon from China that is activated using chemicals, reactivated carbons, activated carbon cloth or activated carbon paper.

The announcement was the culmination of a year-long process that began in March 2006 when Calgon Carbon Corp. and Norit Americas, Inc., filed an anti-dumping petition with the US Government. After the government investigation process that included input from Chinese manufacturers, Chinese exporters, US importers and US purchasers, preliminary higher duties were issued in October 2006 and the recent final ruling puts average anti-dumping duty at about 67 percent for most importers and this will be in addition to the standard 4.8 percent duty for imported activated carbon (HS code 3802.10) making the total duty approximately 72 percent. Some Chinese manufacturers were assessed duty rates as high as 228 percent for not being cooperative or not providing requested information.

Calgon Carbon has a business unit in China and is a major importer of Chinese activated carbon; they will also be subject to additional duties (actually, they were assessed a rate of approximately 78 percent), but according to the DOC, because of the Byrd Amendment, Calgon Carbon and Norit Americas could share 100 percent of the new higher duties for “qualifying expenditures” as they were the damaged parties in the anti-dumping petition. The Byrd Amendment has been repealed by Congress and will expire in Oct 2007.

In 2005, the US imported approximately 85,000,000 pounds of activated carbon from China or about 20 of our activated carbon requirements. China supplied more than half of all activated carbon imports; most of it was coal-base steam activated type. Most other activated carbon imports are coconut shell activated carbon from other Asian countries such as Sri Lanka, Philippines and Indonesia.

The ITC final report on the new activated carbon tariff (Certain Activated Carbon from China, Investigation No. 731-TA-1103 (Final) USITC Publication 3913, April 2007) is now available. Copies can be requested from the ITC by calling (202) 205-2000 or faxing (202) 205-2104.

In the US, Calgon manufactures activated carbon from bituminous coal and Norit Americas manufactures activated carbon from lignite, sub-bituminous and bituminous coal. Meadwestvaco is the third domestic manufacturer (not a party to the anti-dumping petition). They manufacture activated carbon from wood for special applications.

There is very little activated carbon manufacturing in Europe, Canada and the rest of the Americas as most is made from coal or wood in the US and China or coconut shell elsewhere in Asia. Chinese activated carbon has increased in price 10-20 percent in recent years due to coal shortages, currency evaluation, ocean freight increases and general inflation. Now, with the added duty resulting in average 72 percent total tariff, the activated carbon market is experiencing ‘sticker shock’ in many markets. Activated carbon prices to end users are now 30 - 70 percent higher than they were just three to four years ago.

Activated carbon users should re-evaluate their activated carbon application and consider changing the grade or type of activated they buy in an effort to reduce their costs. For example, if one used acid-washed coal base activated carbon for water filtration or water filter manufacturing, one might now look at regular coconut shell activated carbon as an alternative: it may be less expensive and actually have better properties for the application such as higher activity, better attrition resistance and less dust. In the past, many users bought acid-washed coal base activated carbon because of concern of leachable heavy metals from coal base activated carbon, but coconut shell activated carbon usually does not have that concern. Historically, coconut shell activated carbon was not used in many applications because coal base was less expensive, but that dynamic is now out of date and coconut shell activated carbon is very competitive.

The grade of the carbon should also be investigated as one might be using a highly active carbon where a regular activity carbon at lower price may suffice. Activated carbon activity is typically measured in terms of iodine number of 500 – 1500 mg/g, or carbon tetrachloride (CTC) percent activity of 35 – 90. If one is using an 1100-iodine number carbon, the price would be higher than a 900 iodine number carbon or one might use a lesser amount of a much higher activity carbon and save money overall.

The current activated carbon market has just come through a year of confusion and uncertainty and there are signs of product shortages. Many importers did not bring in much product pending tariff resolution and other importers have been assessed much higher than average duty and have stopped importation of activated carbon from China. The domestic manufacturers will pick up business due to product shortages, but they cannot make up the entire product shortfall. It would be prudent to talk to your activated carbon supplier and place orders well in advance of predicted need for the balance of this year.

This article was published in the Water Conditioning & Purification magazine June 2007 issue.

THE HANDLING AND CARE OF ACTIVATED CARBON

By Robert Potwora

Activated carbon adsorbent media is easy to use and easy to handle. If stored properly from contaminating vapors and liquids, it has an indefinite shelf life. It is non-toxic and relatively nonflammable. If it has become wet or damaged through improper storage, it usually can be dried out or restored easily. After it has become saturated with contaminants, it often can be reactivated to virtually its original adsorptive capacity with only a slight volume loss during reprocessing.

Activated carbon is a form of commercially pure carbon typically manufactured from coal, wood, peat or coconut shell having a microscopic physical structure. Each granule contains millions of tiny passageways or pores, which provide a tremendous internal surface area and which accounts for its adsorptive power. The surface area of activated carbon is typically 600 to 1200 square meters per gram depending upon the type and grade of product. It is used to purify air and water, recover valuable vapors and liquids, catalyze chemical reactions and aid in the manufacture of highly purified products. Activated carbon is available in a wide variety of granular sizes, powders, beads, shaped pellets, cloth, pads, and fibers. The physical form used is dictated by the service application and in some cases, pressure drop considerations.

SHIPPING REGULATIONS: There are no special transport regulations and restrictions with most types of activated carbon. No special transport regulations apply to most steam activated carbon. Some chemically activated carbons that contain a high volatile content may spontaneous combust. If they do not pass a special test to exempt them, then they must be shipped as spontaneous combustible.

BAGS OR BULK CONTAINER DELIVERY: Typical packaging options include large polypropylene supersacks (1000 - 2000 pounds), mini polypropylene supersacks (200 – 500 pounds), small paper bags (20 – 55 pounds), Gaylord type boxes (200-1000 pounds) and steel or fiber drums (50 – 200 pounds). When granular activated carbon (GAC) is received in bags or bulk containers, the dry carbon is usually fed through a hopper into an eductor system that provides both the transport water and pressure for motive force. The actual pressure requirements and water flow rate for proper operation of the eductor will depend on the length of transport lose and the vertical lift.

Water pressures of 60-100 psig and capacities (150-250 gpm) adequate to transport slurries of 1-3 pounds per gallon at 4-7 feet per second have usually been adequate. In order to minimize carbon abrasion, the maximum velocity in the transfer piping should not exceed 10 feet per second and should not have sharp bends. Carbon discharge hoses are 4 inches in diameter, 25 foot lengths, and have quick connect fittings on the ends for easy hook-up and disconnection.

In lieu of unloading the bags or bulk containers by slurry, the bags or bulk containers can be unloaded dry directly into the vessel provided that a liquid cushion has been previously added to the vessel. This serves to minimize attrition of carbon granules during loading and to assist in wetting the carbon granules. The bulk containers (bulk bags) have straps on the top of the bag for lifting by crane or by forklift. The bulk bags have a built in discharge chute on the bottom of the bag which has to be unfastened in order to deliver the bag contents.

A 1,100 pound bulk bag of dry carbon can be emptied in this manner in about one minute. If the dry carbon is placed directly into the vessel in this manner, it should be allowed to sit overnight in water prior to backwashing to ensure proper wetting and de-aeration. Dry unwetted carbon particles containing air in the pores will have a density only slightly higher than water and can be lost from the system during backwashing.

BULK TRUCK DELIVERY: When GAC is delivered in pneumatic bulk trucks, it is unloaded from the truck by a water slurry transport process which minimizes carbon particle attrition. The bulk truck containing the dry carbon is filled with water prior to discharge to produce a carbon slurry. The tank truck is sealed and pressurized by a self contained blower, and, the air pressure provides the motive force to move the carbon in a carbon/water slurry out of the bulk trailer and into the carbon vessel. Using this unloading method, the bulk trailer functions much like a blow case.

The nominal capacity of the bulk truck is either 1500 cubic feet or 1800 cubic feet. Depending on the actual density of the carbon, the 1500 cubic feet tanks can hold approximately 38,000 pounds and the 1800 cubic feet tanks can hold approximately 45,000 pounds of dry virgin activated carbon. NOTE: For transporting spent and/or wet carbon, the total weight capacity of the bulk trailer is the same; however, the volume capacity of the bulk trucks for spent carbon is approximately half of the virgin volume since the spent carbon is estimated to be almost twice the weight of dry virgin carbon.

GAC PREPARATION FOR OPTIMUM PERFORMANCE: A new bed of GAC must be de-aerated by soaking the GAC in clean water for 16 hours or overnight. De-aeration is critical to proper performance because most of the surface area available for adsorption is contained in an extensive collection of tiny pores inside the activated carbon particle. When the carbon arrives in a dry state, these pores contain air. If the carbon is not de-aerated before use, air bubbles will prevent water from entering the pores, resulting in poor adsorption performance.

After soaking, backwash the carbon (rinsing in an up flow mode) for 15-30 minutes until the carbon fines are removed. The backwash flow rate should be set to achieve 30-50% bed expansion. Check to ensure there is enough freeboard so the GAC will not be washed out of the vessel. A thorough backwashing removes carbon fines that may otherwise become entrained and carried further into the system.

This combination of soaking and backwashing removes the majority of soluble minerals that would affect the pH or conductivity of the water being treated. The carbon is now ready to be put into service.

During operation suspended particles such as floc, microorganisms, and precipitates can accumulate in the GAC filter. As particles accumulate, there is noticeable head loss; the rate of filtration can be reduced. In severe cases, floc or particulates may pass through the filter to contaminate the treated water. Backwashing is necessary to remove these entrapped particulates and to properly maintain the GAC filter. GAC filters can require regular backwashing, the schedule of which depends upon the operating conditions, the degree of pretreatment prior to the GAC filters, and the quality of the influent. Without proper maintenance of the GAC filter, the adsorptive capability of the GAC filter can be compromised, shortening the overall service life.

USAGE: Activated carbon deteriorates only by doing work, that is, by acting as a catalyst or adsorbing vapors, gases and dissolved substances. Because it is relatively pure carbon, it is resistant to most acids, alkalis, chemicals, and corrosive substances. Repeated heating and cooling has little effect on its physical structure. (In solvent recovery plants, the adsorbent has been subject to as many as 10,000 heating and cooling cycles with no appreciable breakdown of the granules or pellets.)

The best grades of granular activated carbon are hard and abrasion resistant, but methods of handling that tend to grind the product should be avoided. In vapor treatment systems, a high-velocity or non-uniform air flow may cause movement of the particles and rapid wear or breakage of the granules, particularly if the top of the carbon bed is not held in place by a screen. Upward flow of fluid at high velocities during adsorption should be avoided, because it tends to lift the granules and causes channeling. The method of handling activated carbon must be suited to the exact character of the product being used. For example, a powder has different considerations in connection with its handling than does a granular material. Impregnated carbons generally have somewhat lower ignition points than non-impregnated carbons. There are exceptions to this, but one must give special attention to ignition points in connection with carbons which have been impregnated or given other special treatments. Manufacturer product specification sheets and MSDS information provide important details such as carbon ignition temperature.

For the purification of air in living and working spaces, the adsorbent should be reasonably dry. It is not sensitive to moisture, but if it is dripping wet, its capacity will be reduced. If it has become saturated, it can be dried in an oven at 200°F to 250°F. Wet activated carbon tends to corrode mild steel, aluminum, and some other metals. For wet applications, coated carbon steel, stainless steel, monel nickel, plastic, glass or ceramics can be employed satisfactorily for container vessels. For most dry applications, carbon steel, aluminum, plastic or paper are suitable for container materials.

If a particular grade of granular carbon contains too much dust or fine granules for a given application, they may be removed by screening, air-hosing, or water-washing. The dustiness of most powdered carbons can be reduced by adding 10 to 30 percent moisture.

HEALTH AND SAFETY: Activated carbon is not toxic. Many types meet FDA Codex requirements for food grade applications and many are also approved by AWWA and NSF for drinking water treatment. In addition, some grades of activated carbon are USP certified and are taken internally for various medicinal treatments. Dust exposure is a concern with some activated carbons and normal dust handling procedures should be used such as eye protection and dust masks for personnel handling the carbon and room dust filters to keep dust level under control.

Activated carbon is combustible, but not easily ignited. In the absence of a forced draft, even hot activated carbon supports combustion with difficulty and, under some conditions, will extinguish on its own accord. It should not be subjected to a blast of air at temperatures above approximately 400°F, however. Where high concentrations of vapors are adsorbed, the heat of adsorption (adsorption is an exothermic reaction) may be sufficient to raise the temperature of the carbon appreciably. In such cases, it may be best to operate with the carbon partially wet with water, as is typically done in solvent recovery plants, or to reduce the vapor concentration by adding additional air.

Care must be exercised in entering tanks or other enclosed spaces which contain large quantities of activated carbon. Wet activated carbon adsorbs or depletes oxygen from air; therefore, workers should never enter vessels or confined tanks of wet activated carbon without observing confined space procedures. Atmosphere sampling and work procedures for potentially low oxygen areas should be followed. This precaution should be observed even though the carbon may not have been used in service.

SERVICE LIFE: Activated carbon has a definite life or capacity in performing its function. When the limit has been reached, the adsorbent should be replaced or reactivated. It is good practice to have at least one spare charge on hand so that the original one can be replaced whenever necessary.

SPECIAL SERVICE CONDITIONS: Activated carbon is a powerful adsorbent and catalyst. Although most of its reactions and properties are reasonably well known, it must be regarded with care in unusual circumstances. Activated carbon can adsorb most types of molecules (there is a great difference in degree, depending on the type of molecule adsorbed and the ambient conditions), and if the conditions change, the carbon can give up these molecules into the surrounding space.

BACTERIAL GROWTH: Carbon can adsorb nutrients required by bacteria and, after such adsorption has taken place, it is possible for bacteria to grow on the outside of the carbon granule and, to some degree, within the large pore entrances. Bacteria can be eliminated by heat sterilization, high pH soak, low pH acid soak, or through the use of some other chemicals. There are types of carbon available which contain biocides which do not add any poisonous substances to the water, but will control bacteria growth. Bacteria which are free-floating in the water can be removed by activated carbon because it can act as a filtering agent also.

REGENERATION AND REACTIVATION: Spent activated carbon can be regenerated on-site if contaminated with low boiling impurities. This is usually accomplished with steam. It can also be sent to an off-site reactivation facility, land filled, or incinerated. RCRA hazardous spent activated carbon must be handled accordingly and sent to a RCRA approved facility for disposal.

By Kimberly Walsh

Carbon Resources continues to experience tremendous growth. First quarter sales this year were ahead of same period in 2006. I believe we can attribute the 35% growth to not only the demand for high quality products but also for unique products such as our low density non-Asian coal base carbon as well as our surface enhanced Spartan Series. We call this our “A” series product which will account for the largest percentage of our new customer base year to date.

The new 60% plus duty on Chinese coal base activated carbon also has had an effect on our business. The large duty that now must be paid upon ocean container arrival puts some of the smaller companies at a disadvantage due to the large cash outlay required. In the second half of 2007 we have new contracts totaling over one million pounds for coal base carbons out of China. As the China economy grows and China’s domestic demands require more coal base carbons, the need for strong alliances with our manufacturing plants becomes even more critical as supply tightens and quality has a potential to be compromised. Our tenure with the Chinese manufacturing plants puts us in an unique position to insure we can continue to service our customers with the quality products they require.

The most exciting news is our joint venture in a brand new activated carbon facility in Mexico that will have a design capacity of 6 million pounds a year of coconut shell activated carbon. This facility should be operational in August and will have state-of-the art manufacturing and testing equipment. Carbon Resources will be the only company to have a manufacturing facility of coconut shell carbons in North America. We will also be adding “value added” processing for not only our coconut shell products but for our coal base products as well.

We would like to take this opportunity to thank all our customers who have put their trust and confidence in making us the best that we can be. We will continuously improve our products as well as strive for excellence in customer service and technical support.

By Robert Potwora

Congratulations to Frank who will win an iPod nano for submitting the question below. Don’t forget we are soliciting questions from our readers on activated carbon technology. Please submit your questions to Robert@carbonresources.com. One question will be selected and answered in the next newsletter. If your question is selected and printed in the newsletter, you will win an Apple iPod nano. All questions will receive a reply. Questions will be answered by Robert (Bob) Potwora. He is the Technical Director for Carbon Resources LLC.

Question:

How can you tell when activated charcoal is all filled up or it cannot absorb anymore? Is there any machine or test that can be applied to it to give an indication?

Answer:

The most precise way is to test the carbon’s effluent for the impurity you are trying to remove. If the desired concentration of the contaminate in the effluent is exceeded, then it’s time to change the carbon.

If you are treating air, I have seen some success with potassium permanganate detectors. The potassium permanganate media changes purple to brown when spent. The detector is placed in the carbon’s effluent. When the media in the detector changes to a brown color, breakthrough is occurring and the activated carbon should be changed.

Iodine or carbon tetrachloride testing could be done on a carbon sample from the vessel and compared to virgin properties. If you are adsorbing low concentrations (ppb or low ppm) of impurities this won’t work. The problem with this method is the adsorbed organics may come off when testing the sample. Also, the results won’t tell if the carbon is spent or all filled up, but only give a general indication.

If the concentration of impurities in the influent and flow is known, we can estimate how long the carbon will last.