Studies on feasiblity of hydrochloric acid recycle and iron-II-chloride recovery in pickling operation in steel cord industry
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Date
1999-09
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Publisher
The Middle East Technical University, The Department Of Chemical Engıneering
Abstract
Bu tez çalışması esnasında, atık pikling banyosu sıvılarının uygulanabilir geri kazanım proseslerinin, proses sentezi ve tasarımlarının yapılması amaçlanmıştır. Ayrıca uygulanabilir proseslerin ekonomiksel karşılaştırılması yapılmıştır. Seçilen uygulanabilir prosesler HCl’in FeCl(2)’ye çevrilmesi, Evaporasyon Prosesi ve FeCl(2)’ün kristalizasyonu prosesleridir. İlk olarak HCl’in FeCl(2)’ye dönüştürülmesi prosesi çalışılmıştır. Bu proseste bütün kullanılmamış HCl, Fe ile reaksiyona sokulmak suretiyle sıvı FeCl(2) çözeltisi elde etmek amaçlanmaktadır. Evaporasyon prosesinde, literatür atık pikling sıvısı kompozisyonu baz olarak alınarak, değişik akış diyagramı alternatiflerinin bilgisayar simulasyonları yapılmış ve optimum proses akış diyagramı elde edilmiştir. Elde edilen optimum proses akış diyagramına göre, endüstriyel veriler için akış diyagramı entegrasyonu yapılmıştır. Evaporasyon prosesinde geri kazanım için iki alternatif bulunmaktadır, birincisi katı oluşumuna izin vermeyen geri kazanım prosesi diğeri ise katı oluşumuna izin veren geri kazanım prosesidir. Katı oluşumuna izin vermeyen geri kazanım prosesinde, sıvı fazda kalan HCl 'i bertaraf etmenin yolu HCl’in Fe ile reaksiyona girmesi ve FeCl(2) elde edilmesidir. Çalışılman üçüncü geri
kazanım alternatifi ise FeCl(2)‘ün kristalizasyonu prosesidir. Ayrıca laboratuvar ölçeğinde atık pikling banyosu sıvısındaki FeCl(3)’ün hidrojenle reaksiyonuyla FeCl2 elde edilmiş ve bu reaksiyonun olabilirliği test edilmiştir. FeCl(3)’ün FeCl(2)’e indirgenmesi geri kazanılan taze asit içindeki FeCl3 birikimini önlemek için gereklidir. Kristalizasyon prosesinde taze banyo için eklenecek HCl’in kristalizasyon ünitesinden önce eklenmesi fikri uygulanarak FeCl(2) çözünürlüğü düşürülmüştür. Bütün alternatifler için ekipman fiyatları hesaplanmıştır. Sabit yatırım maliyeti, ekipman fiyatları baz alınarak hesaplanmış ve ayrıca bütün prosesler için yıllık çalışma maliyetleride hesaplanmıştır. Proses ekonomileri açısından alternatifler kıyaslanmıştır. En ekonomik proses HCl’in FeCl(2)’e çevrilmesi prosesi olarak bulunmuştur.
During the present study, it was aimed to have process synthesis and design of suitable recycle/recovery options for waste pickle liquors from pickling baths. These processes were compared through the consideration of the economics of the processes. The processes selected were Conversion of HCl to FeCl(2), Evaporation Process and Crystallization of FeCl(2). The first reclamation process studied was the Conversion of HCl to FeCl(2), with that process it was aimed to have all the waste pickle liquor as aqueous FeCl(2) solution. In the Evaporation process case, firstly the flowsheet simulations of different processes were completed for data based on composition of waste pickle liquor given in the literature. Final flowsheet was obtained for literature data. Basing on previous flowsheet development, flowsheet integration for the industrial data was done. There were two cases for this recovery one allows solid formation in the evaporator, while the other not. For the further treatment of liquid product from Evaporation Process without solid formation, containing significant amount of HCl, possible alternative was reacting HCl with Fe to convert HCl to FeCl(2). The third alternative studied was Crystallization of FeCl(2) Process. Furthermore, the little content of FeCI(3) in waste pickle liquor was converted to FeCl(2) with hydrogen in the laboratory in order to confirm the possibility of that conversion reaction. The conversion of FeCI(3) to FeCI(2) is a must to eliminate the accumulation of FeCI(3) in the mother liquor. For the crystallization, addition of make-up acid before crystallization unit was chosen to increase the chloride ion concentration that would decrease the FeCI(2) solubility. For each alternatives purchased equipment cost was calculated. Fixed Capital Investment (FCI) for each alternative was calculated based on purchased equipment cost. Yearly operating costs were calculated. The alternatives were compared with each other with in the perspective of process economics. The most feasible process was found out to be the as Conversion of HCl to FeCI(2) process.
During the present study, it was aimed to have process synthesis and design of suitable recycle/recovery options for waste pickle liquors from pickling baths. These processes were compared through the consideration of the economics of the processes. The processes selected were Conversion of HCl to FeCl(2), Evaporation Process and Crystallization of FeCl(2). The first reclamation process studied was the Conversion of HCl to FeCl(2), with that process it was aimed to have all the waste pickle liquor as aqueous FeCl(2) solution. In the Evaporation process case, firstly the flowsheet simulations of different processes were completed for data based on composition of waste pickle liquor given in the literature. Final flowsheet was obtained for literature data. Basing on previous flowsheet development, flowsheet integration for the industrial data was done. There were two cases for this recovery one allows solid formation in the evaporator, while the other not. For the further treatment of liquid product from Evaporation Process without solid formation, containing significant amount of HCl, possible alternative was reacting HCl with Fe to convert HCl to FeCl(2). The third alternative studied was Crystallization of FeCl(2) Process. Furthermore, the little content of FeCI(3) in waste pickle liquor was converted to FeCl(2) with hydrogen in the laboratory in order to confirm the possibility of that conversion reaction. The conversion of FeCI(3) to FeCI(2) is a must to eliminate the accumulation of FeCI(3) in the mother liquor. For the crystallization, addition of make-up acid before crystallization unit was chosen to increase the chloride ion concentration that would decrease the FeCI(2) solubility. For each alternatives purchased equipment cost was calculated. Fixed Capital Investment (FCI) for each alternative was calculated based on purchased equipment cost. Yearly operating costs were calculated. The alternatives were compared with each other with in the perspective of process economics. The most feasible process was found out to be the as Conversion of HCl to FeCI(2) process.
Description
TENMAK D.N. 333
Keywords
HCl Recovery, HCl geri kazanımı, Waste pickle liquor, Atık pickling sıvısı, Process integration, Proses entegrasyonu
Citation
Özdemir, T. (1999) Studies on feasiblity of hydrochloric acid recycle and iron-II-chloride recovery in pickling operation in steel cord industry. (Yayımlanmamış yüksek lisans tezi). Ankara : The Middle East Technical University, The Department Of Chemical Engıneering.