Trinidad Polypropylene Plant, Trinidad and Tobago

As part of an ongoing process of industrialisation on the islands of Trinidad and Tobago, the government is promoting several large construction projects. One of these is a new integrated polypropylene complex.

In April 2006 the country's energy minister, Lenny Saith, announced that the government was examining a project to allow a $1.4bn polypropylene complex to be constructed by a foreign company. This promises plastic materials, available for investment in the toy, automotive parts and appliances markets (downstream diversification).

LyondellBasell, the government of Trinidad and Tobago, the National Gas Company of Trinidad and Tobago (NGC), National Energy Corporation of Trinidad and Tobago (NEC) and Lurgi, have now signed a project development agreement relating to a proposed propylene complex.

The agreement, announced in early September 2008, is intended to provide the relevant framework to govern the relationship among the parties to evaluate jointly the construction and operations of the complex which will be located in Trinidad and Tobago. The partners said that the project is tentatively scheduled to start up in 2012.

The project will involve the construction of a plant producing 490,000tpa of polyolefin as well as a methanol plant and a methanol-to-propylene facility.

New plant

The new fully integrated polypropylene complex will include a methanol-to-propylene processing unit, a methanol production unit (natural gas to methanol) and also a 450,000t/yr polypropylene production plant. The methanol will be produced from natural gas feedstock from fields near Trinidad and Tobago by the NGC and NEC.

The methanol to propylene technology (MPT) will be provided by Lurgi AG of Germany and the propylene plant will be based upon Spherizone technology from Basell Polyolefins of the Netherlands. The plants are set to begin construction by the end of 2008 to the start of 2009 and would be on stream by late 2012.

Spherizone technology

The process is based on multizone circulating reactor (MZCR) technology. The reactor consists of two interconnected polymerisation zones. The first zone (riser) is the fast fluidisation zone.

Unlike typical gas-phase reactors, the gas velocity in the fast fluidisation zone is well above the transport velocity. Growing polymer particles are carried away or entrained in the gas stream and are circulated to the second polymerisation zone.

The second zone is similar to a packed-bed reactor, where the polymer particles flow downwards under the force of gravity with a density approaching the bulk density of the polymer, and are recirculated back to the first zone. Thus, the growing particles circulate between the two interconnected polymerisation zones under different flow regimes.

Make-up monomer, co-monomer, molecular weight regulators, catalyst and optional inert gases are continuously fed to the reactor, while polymer produced is discharged through the downcomer, thus maintaining the material balance in the reactor.