Purified Terephthalic Acid, or PTA, is a vital component lurking behind many of the materials we use every day. This white, crystalline acid might not be a household name, but it forms the backbone of numerous essential products. From the plastic water bottles we carry to the polyester clothing we wear, PTA silently shapes our world. In this article, we will explore more about PTA and its production process before it became the end-product that we use daily.
PTA Production Process
Purified terephthalic acid (PTA) production involves several key stages. Here's a breakdown of the process with citations for each step:
PTA Process (source : valcogroup)
Step 1: Feedstock and Reaction
The story of PTA starts with paraxylene (PX), an aromatic hydrocarbon separated from crude oil during the refining process. This serves as the primary feedstock for PTA production. Inside an oxidation reactor, PX reacts with acetic acid as a solvent. Air, or sometimes enriched oxygen, is introduced to convert PX into terephthalic acid (TPA). This reaction releases heat (exothermic), necessitating cooling systems to maintain optimal temperature within the reactor.
Step 2: Purification
The initial product exiting the reactor, known as Crude Terephthalic Acid (CTA), still contains impurities. To achieve the desired level of purity, a purification stage is necessary. In some processes, the CTA is dissolved in water to form a slurry. This step might be followed by an optional reduction step using agents like sodium formate to remove further impurities.
Step 3: Crystallization and Separation
Once sufficiently purified, the solution is sent for crystallization. Here, the purified terephthalic acid precipitates out of the solution, forming crystals. These crystals are then separated from the remaining liquid (mother liquor) using techniques like rotary filters. The mother liquor might be recycled back into the process for improved efficiency.
Step 4: Washing and Drying
The separated PTA crystals undergo a washing stage using water to remove any remaining impurities. Following the washing stage, drying is essential. Fluidized bed dryers or similar equipment remove moisture from the washed crystals, ensuring a final product suitable for storage and transportation.
Step 5: End Product
The dried PTA is now ready for the next stage of its journey. It is either stored or packaged for transportation to polyester production facilities, where it will be transformed into a variety of essential products that touch our lives in countless ways.Furthermore, PTA production technology variations exist. Specific details may differ between facilities depending on the chosen process and optimization for factors like efficiency and yield.
Safety measures are crucial throughout the process due to flammable and potentially hazardous materials.
In conclusion, PTA is a basic material that can be used in everyday items, such as plastic bottles to clothing. This indicates that PTA is an important chemical in human life. The process of PTA formation begins with the raw material, PX, which goes through an oxidation process to become CTA. CTA which still contains impurities will be purified and goes through the crystallization and separation process. After CTA is filtered from the mother liquid, the next step is a process with washing and drying so that it becomes an end product (PTA) which will be sent to polyester production.
References :
https://mitsubishichemical.co.id/product/our-product/pta
https://www.valcogroup-valves.com/faq-2/pta-terephthalic-acid-manufacturing-process-of-pta/
Lu, X., Xie, S., Li, S., Zhou, J., Sun, W., Xu, Y., & Sun, Y. (2021). Treatment of purified terephthalic acid wastewater by ozone catalytic oxidation method. Water, 13(14), 1906.
This article is written by :
Annissa Dewi Rianti
Sales & Marketing Staff
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