No Sé

IFA Technical Conference
Marrakech, Morocco 28 September-1 October 1998

International Fertilizer Industry Association - Secretariat: 28 rue Marbeuf - 75008 Paris - France Tel. +33 1 53 93 05 00 - Fax +33 1 53 93 05 45/47 - ifa@fertilizer.org - www.fertilizer.org

Date of Receipt: 16 September 1998

PHOSPHATE TECHNOLOGY FOR THE NEXT MILLENNIUM1 R.L. Hemmings, C.J. Felice and M.W. HuangRaytheon Engineers & Constructors Inc, United States
SUMMARY Raytheon's presentation at the 1997 AIChE conference in Clearwater, Florida, featured a conceptual singletrain design for a 1,000 tons per day P2O5 phosphoric acid plant. This design concept featured a single Raytheon Isothermal Reactor vessel converting the phosphate rock slurry to gypsum and phosphoric acid. Now, in 1998, Raytheon canannounce that this same reactor, the largest single reactor vessel designed by Raytheon, can be operated in such a way as to process up to 2,000 tons per day of P2O5. This much higher rate is the result of application of new information and technology. An AspenPlus simulation of the Isothermal Reactor System that confirms the production rate of the design. The model was developed inhouse by one ofRaytheon’s simulation experts, using the powerful AspenPlus process simulation software, Release 9-3.2. This software contains the electrolyte simulation capability to simulate all the complex chemistry taking place in the Raytheon Isothermal Reactor/Crystallizer. RESUME La présentation de Raytheon à la conférence de AIChE en 1997 à Clearwater, en Floride concernait le plan conceptuel d'unatelier d'acide phosphorique de 1000 t/j P2O5 en une seule ligne. Il comportait une cuve d'attaque unique isotherme Raytheon transformant la bouillie de phosphate en gypse et en acide phosphorique. Actuellement, en 1998, Raytheon peut annoncer que le même réacteur, la plus grande cuve d'attaque conçue par Raytheon, peut fonctionner de telle façon qu'elle produit 2000 t/j P2O5. Ce rendement accrurésulte de l'application d'informations et de technologies nouvelles. Une simulation AspenPlus du système de réacteur isotherme confirme la capacité de production du modèle. Le modèle a été développé par nos moyens internes par un des experts de simulation de Raytheon, utilisant le puissant logiciel de procédé de simulation AspenPlus, Version 9-3.2. Ce logiciel possède la faculté de simulation del'électrolyte pour simuler toute la chimie complexe qui se passe dans le réacteur isotherme/cristalliseur Raytheon. ✦✦✦ Background Raytheon has developed a new Isothermal Reactor/Crystallizer of a size that will produce up to 2,000 MT/d of P2O5, is 40 feet (12+ meters) in diameter with a working volume of 46,000 cu ft (1,300 cubic meters). This i, ii, reactor was described in previous papers anddemonstrates the flexibility and the stretch capability of the Isothermal Reactor/Crystallizer operating parameters. The Isothermal Process for converting phosphate rock into gypsum crystals and phosphoric acid consists of a simple train of equipment: a conveyer from the feed pile; a rock slurry storage tank or tanks; rock slurry pumps; the Isothermal Reactor vessel; a condenser for cooling; filter feedtanks and associated pumps; and the final filters. The heart of the process is the Isothermal Reactor which, if operated carefully as described in nd the 2 reference, and with a detailed understanding of the chemical reactions taking place inside the reactor, can be used to double the previously identified “maximum” throughputs. Under careful control, this reactor and crystallizer provide theenvironment for growth of large and easily filtered crystals by employing a high rate of recirculation to maintain the desired supersaturation level of the slurry contents of the vessel, but not at too high a rate to physically break the crystals, in combination with a controlled rate of evaporative cooling. In the Isothermal reactor/crystallizer, the recirculating slurry contents are exposed to...