Urea Production Technology: Recent Developments

Keywords: Urea production, Pool condenser, CO₂ stripping, Revamp, Debottlenecking, MEGA urea plant, Urea 2000plus.

To lower urea fabrication costs through the means of economy of scale, Stamicarbon has developed a new mega plant concept. This concept (4500 mtpd) is based on proven process steps whereby the sizes of the required high pressure equipment will not go beyond sizes needed for a 3250 mtpd pool condenser-type CO₂ stripping urea plant. The plant will be equipped with a medium pressure recycle stage, without a separate ammonia recycle loop but with the advantage of the low water concentration in recycle carbamate formed at medium pressure, which in turn results in higher conversion figures and a lower steam consumption. All individual process steps are commercially proven and no scale-up of equipment used in a 3250 mtpd plant is needed to satisfy the equipment requirements for a 4500 mtpd plant using this new concept.

Stamicarbon has revamped a conventional urea plant (200 bar synthesis pressure) into a pool condenser plant. The original plant was designed for 550 mtpd, and has been revamped in two stages. After the last revamp, which is discussed here, the plant is scheduled to produce 1750 mtpd. As a pool condenser provides retention time for the synthesis liquid and consequently takes care of a significant part of the urea conversion this revamp uses the reactor installed for the original 550 mtpd plant capacity.

Furthermore the change from conventional technology to CO₂ stripping technology has dramatically reduced utility consumptions as well.

Mark Brouwer, Stamicarbon BV, PO Box 53, NL-6160 AB Geleen, The Netherlands.

15 pages, 5 figures, 3 tables.