Excluding eastern European countries and China, where production figures have not been published, the world pro
To To atmosphere atmosphere
duction capacity of activated carbon was estimated to be 375,000 metric tons in 1990 (35). The price of most products was 0.70 to 5.50 $/kg, but some specialty carbons were more expensive (36, pp. 731.2001P, 731.2001Q). Forty percent of the production capacity was in the United States, 30% in western Europe, 20% in Japan, and 10% in other Pacific Rim countries (Table 2).
Production capacity was almost equally split between powdered and nonpowdered activated carbon products. Powdered activated carbon, a less expensive form used in liquid-phase applications, is generally used once and then disposed of. In some cases, however, granular and shaped products are regenerated and reused (35). In 1990 production capacity for granular and shaped products was split, with about two-thirds for liquid-phase and one-third for gas-phase applications (37).
Over the last decade, production capacity in the United States remained essentially unchanged, but minor fluctuations occurred in response to changes in environmental regulations (36pp.731.2000S-731.2000Y). A similar reaction was noted worldwide (35). The current demand for activated carbon is estimated at 93% of production capacity. The near-term growth in demand is projected to be approximately 5.5%/year (37pp.4,5).
In 1970 the U.S. Congress enacted the Clean Air Act, the Clean Water Act, and the Safe Drinking Water Act. Because activated carbon can often be used to help meet Environmental Protection Agency (EPA) regulations, the U.S. activated carbon industry reacted by increasing its production capacity. A proposed amendment to the Safe Drinking Water Act in 1979 required the use of granular activated carbon systems, but the amendment was not enacted. In response to the projected increase in demand for activated carbon, production capacity remained high until the late 1980s, but when the anticipated need did not materialize, some production facilities were shut down. Currently, because of stricter EPA regulations implementing all three acts in 1990, the industry will increase production capacity by 25% during the next several years (35,38).
The estimated production capacity of activated carbon in the United States is shown in Table 3 for seven manufacturers (35pp.54-65). The principal producers are Cal-gon Carbon (37%), American-Norit (26%), Westvaco (19%), and Atochem (10%). Several other companies purchase activated carbon for resale but do not manufacture products.
Western Europe has seven manufacturers of activated carbon. The two largest, Norit and Chemviron (a subsidiary of Calgon), account for 70% of western European production capacity, and Ceca accounts for 13% (35p.13), Japan is the third-largest producer of activated carbon, having 18 manufacturers, but 4 companies share over 50% of the total Japanese capacity (35p.25-32). Six Pacific Rim countries account for the balance of the world production capacity of activated carbon, 90% of which is in the Philippines and Sri Lanka (35p.13). As is the case with other businesses, regional markets for activated carbon products have become international, leading to consolidation of manufacturers. Calgon, Norit, Ceca, and Sutcliffe-Speakman are examples of multinational companies.
Activated carbon is a recyclable material that can be regenerated. Thus the economics, especially the market growth of activated carbon, particularly granular and shaped products, is affected by regeneration and industry regeneration capacity. The decision to regenerate an activated carbon product is dependent on the cost, size of the carbon system, type of adsorbate, and the environmental issue involved. Large carbon systems, such as those used in potable and wastewater treatment, generally require a high-temperature treatment, which is typically carried out in rotary or multihearth furnaces. During regeneration, carbon losses of 1 to 15% typically occur from the treatment and movement of the carbon (39). However, material loss is compensated for by the addition of new carbon to the adsorber system. In general, regeneration of spent carbon is considerably less expensive than the purchase of new activated carbon. For example, fluidized-bed furnace regeneration of activated carbon used in a 94,600-m3/day water treatment system cost only 35% of new material (40). For this system, regeneration using either infrared or multihearth furnaces was estimated to be more expensive but still significantly less so than the cost of new carbon.
Because powdered activated carbon is generally used in relatively small quantities, the spent carbon has often been disposed of in landfills. However, landfill disposal is becoming more restrictive environmentally and more costly. Thus large consumers of powdered carbon find that regeneration is an attractive alternative. Examples of regeneration systems for powdered activated carbon include the Zimpro/Passavant wet air oxidation process (41), the multihearth furnace as used in the DuPont PACT process (41pp.389-447,42), and the Shirco infrared furnace (40p.51,43).
Other types of regenerators designed for specific adsorption systems may use solvents and chemicals to remove susceptible adsorbates (44), steam or heated inert gas to recover volatile organic solvents (45), and biological systems in which organics adsorbed on the activated carbon during water treatment are continuously degraded (46).
Capacity (1Q3 t)
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