Data
CHEMICAL ENGINEERING
01-01-2012
Pagina Foglio
2/3
- - Gases/air - - Liquids - - Urea solution / melt / slurry
Carbamate
- - Staam / waler
FIGURE 1. The Stamicarbon Avancore urea process Is a further development of the company's Urea 2000plus technology, and reduces the required plant height to just 22 m - even for large-scale plants (MP and HP = medium and high pressu re)
ment items (and the associated costs). For example, the plant will use Safurex stainless steel - an improved duplex steel devel oped with Sandvik Materials Technology (Sandviken, Sweden; www.smt.sandvik.com). Thanks to the improved corrosion resistance of this new material, the air supply normally used for passivation is no longer required. As a result, the absence of oxygen means there is no need to combust hydrogen; so the H2 converter is eliminated, and the synthesis section has become intrinsically safe with respect to explosion risks. With the quantity of inert gas substantially reduced, less gas has to be vented from the urea synthesis section, so the high-pressure (HP) scrubber can be replaced by a medium-pressure (MP) scrubber. Meanwhile, Stamicarbon continues to find buyers for its Urea 2000plus technology, which was commercialized over ten years ago - still recent for this conservative industry. For example, last July the company signed a license agreement with Hengang Huabe Coal Chemical Industry, Ltd. in the China for a urea granulation plant with a capacity of 1,860 m.t.ld. The plant will be built in Hegang City, Heilongjiang Province, PRC. The urea plant will use Stamicarbon Urea 2000plus Technology, which features a pool reactor, minimum equipment and minimum plant height. Stamicarbon will deliver the process design package, related services and all proprietary high-pressure equip-
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ment, the pool reactor and piping. The high-pressure equipment, pool reactor and piping will be alloyed with Safurex. Start up is planned in 2014. Over the last 15 years Stamicarbon has licensed a total of 15 grassroots and revamped plants in China with capacities up to 3,520 m.t.ld. Meanwhile, Toyo's ACES21 process, which saw its co=ercial debut in 2002, has now been selected for eight urea projects (most recent listed in Table I ). In the ACES21 process (Chern. Eng. , October 2008, pp. 2!Ml1), urea is made by reacting liquid ammonia with liquid CO 2 to form ammonium carbamate, which is then decomposed into urea. In previous designs, the urea synthesis loop consisted of a reactor, a stripper, two carbamate condensers and a scrubber. Energy and investment savings are achieved by integrating the two condensers and the scrubber into a single condenser that has a vertical, submerged carbamate-condensing section (the heat exchanger tubes are submerged in the carbamate solution at the bottom of the condenser}. A packed bed on top of the condenser facilitates the absorption of uncondensed NH3 and CO2 into the recycled carbamate solution.
Other recent announcements Last month, the Saudi Arabian Fertilizer Co. (Safco; www.safco.com. sa), a manufacturing affiliate of the Saudi Basic Industries Corp. (SABIC; Riyadh, Saudi Arabia; www.sabic. com), awarded a turnkey contract for
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