PET-SSP for Bottle Grade

Continuous SSP plants are characterized by longer residence times and larger product hold-ups compared to the melt phase. This is due to the lower processing temperatures and the lower bulk density of the pellets compared to the melt. At today s standard bottle grade capacities of ca. 300 t/d, the typical plant hold-up is approximately 2501, which equates to around 300 m3 of product volume at a bulk density of 800kg/m3. Because the plants make use of gravity flow through the equipment they tend to be very tall - up to 50 m at 300 t/d. 

At such high throughputs and large product hold-ups, these plants are required to be very robust [2], More than one year of continuous production without maintenance is expected. In addition, the process needs to be able to be restarted after power outages of some hours without the loss of further production and with minimal off-spec material. 

The main functions of a PET-SSP plant for bottle-grade applications are as follows  

The typical precursor material specification for bottle grade is as follows  

A standard pellet size and shape has established itself within the industry over recent years. The pellets tend to be cylindrical with a diameter between 2.0-3.0mm and a length of 2-3.5mm. 

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