This paper looks at how the earlier PTA production method involving a multi-stage process with pressure and atmospheric centrifuges and a re-slurry tank can be replaced with one stand-alone device – the rotary pressure filter (RPF).
In the past, to achieve high-quality separation and high purity of certain substances, producers needed to use centrifuge technology to guarantee the requisite product quality. Unfortunately, the very high speeds generated by the machine not only result in high energy bills, but mounting costs from frequent maintenance and repairs. One such substance that previously relied on centrifugation to separate its liquid and solid phases is purified terephthalic acid (PTA), a crucial chemical in the petrochemical industry used for PET bottles and polyester fibers, whose rise in global demand shows no signs of slowing. However, volatile crude prices and rising costs for energy and production facilities mean that market prices for PTA can fluctuate wildly. Smaller plants with a nameplate capacity of less than 800 MT per year are at risk of being sunk by bigger competitors during low-price periods unless they have managed to optimize their process and cut OPEX. An optimized rotary pressure filter (RPF) enables complete filtration between the PTA crystallization and drying stages to be realized in a single, closed step.
The paper looks in detail at the design, operating principle, and performance of a state-of-the-art RPF. Two reference projects from Indonesia and Russia show how the right separation technology can deliver low OPEX while maintaining the same quality, enabling PTA producers to remain competitive even when prices fluctuate. This paper shows also that switching over to a single RPF process can also be the right option for existing plants looking to future-proof their business by cutting costs without compromising on the quality of their product.