An Original and Applied Method for Recovery of Caprolactam from PETKİM Waste Water

Abstract

Synthetic Yarn Industries of Türkiye produce materials including PP, PES, acrylic and nylon-6 type yarns. Of these materials, Nylon -6 yarn is used in textiles and speci cally in sh-net productions. In 1970’s there was an increasing demand for Nylon-6 in native nylon producers in Turkey. In order to meet these demands in 1976, Petkim built a factory and started to produce monomer caprolactam which is the raw material of Nylon-6. In this factory, there were ve different waste water solitions that carry signi cant amount of unrecovered caprolactam which creates environmental pollution as well as economical lost. In order to recover caprolactam, the following method has been developed and applied to the PETKİM waste water at the Laksan recovery plant in Türkiye. First of all, PETKİM caprolactam waste water has been saturated with industrial salt (NaCl), and then extracted with benzene.At the beginning of the recovery process,these salty solutions were extracted totally threefold volume benzene in three-step batch method. After about ten years, the salty solutions were extracted with only equal volume benzene in a reverse current continuous column as a more improved one-step method. Benzene, separeted from caprolactam by distillation, was reused at the next extractions and NaCl, crystallized from saturated waste waters by open-air evaporation, was also reused at the next saturations. 

Keywords

• Caprolactam,benzene,NaCl,extraction,saturation,recovery

PETKİM Atıksuyundan Kaprolaktam Geri Kazanımında Uygulanmış Özgün Bir Metot

Abstract

Türkiye’deki sentetik iplik sanayi; PP, PES, akrilik gibi iplik türleri yanında, naylon-6 iplik de üretmektedir. Bu iplik, tekstil sanayinde ve özellikle de balık ağları yapımında kullanılmaktadır. Naylon-6’nın hammaddesi monomer kaprolaktamdır. Yerli iplik üreticilerinin hammadde ihtiyacını karşılamak için, Petkim 1976’da kaprolaktam fabrikasını kurup işletmeye almıştır. Bu fabrikadan çıkan 5 tür atıksuda, geri kazanılamayan önemli bir miktar kaprolaktam da bulunmakta, ekonomik kayıp ve çevre kirliliği oluşturmakta idi. Aşağıdaki orijinal metot, bu atıksulardan kaprolaktam geri kazanmak için Laksan A.Ş.’de geliştirilmiş; başta kaprolaktam ve naylon-6 geri kazanma tesisi, daha sonra naylon teknik iplik üretme tesisi olan Laksan’da endüstriyel olarak uygulanmıştır. Bu metotda, kaprolaktamlı Petkim atık çözeltisi, önce sanayi tuzu (NaCl) ile doyurulmuş; sonra kesikli metotda 3 kademede toplam üç kat benzen ile ekstrakte edilmiş; yaklaşık on yıl sonra devreye alınan tek kademeli, sürekli (kesiksiz) ve daha verimli metotta da, ters akımla çalışan dik kolonda, sadece eşit hacimde benzen ile ekstrakte edilmiştir. Laktamdan distilasyonla ayrılan benzen, yeni ekstraksiyonlarda; açık havada havuzlarda atık çözeltinin buharlaşmasıyla kristallenen tuz da, yeni gelen Petkim atık çözeltilerinin tuzla doyurulmasında, tekrar kullanılmışlardır.

Keywords

• Kaprolaktam,benzen,tuz,ekstraksiyon,doyurma,geri kazanma

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