Forward osmosis coupled with lime-soda ash softening for volume minimization of reverse osmosis concentrate and CaCO3 recovery: A case study on the coal chemical industry

Author(s):  
Jiandong Lu ◽  
Shijie You ◽  
Xiuheng Wang
2020 ◽  
Vol 81 (12) ◽  
pp. 2674-2684
Author(s):  
Jiandong Lu ◽  
Xiuheng Wang

Abstract Coal chemical industry (CCI) generally utilizes reverse osmosis (RO) for water reclamation, which generates a highly concentrated stream containing refractory organic substances and high-concentration total dissolved solids (TDS). To address this issue, the present work focuses on volume reduction of RO concentrate (ROC) produced from CCI by forward osmosis (FO). We investigated the effects of membrane orientation and draw solution (DS) concentration on FO performance. Foulant removal was tested by using chemical cleaning, physical cleaning and osmotic backwash (OB). AL-FS (active layer facing feed solution) mode outcompeted AL-DS (active layer facing draw solution) mode, achieving a flux of 26.4 LMH, 92.5% water reclamation and energy consumption of 0.050 kWh·m−3 with 4 M NaCl as DS. The FO process was able to reject >98% SO42−, Mg2+and Ca2+, 92–98% Si and 33–55% total organic carbon (TOC). Ten-cycle (10 × 20 h) accelerated fouling test demonstrated approximately 30% flux decline in association with Si-containing foulants, which could be removed almost completely through OB with 97.1% flux recovery. This study provides a proof-of-concept demonstration of FO for volume reduction and water reclamation of ROC produced from CCI, making the treatment of ROC more efficient and more energy effective.


2021 ◽  
Vol 13 (9) ◽  
pp. 4851
Author(s):  
Ming-Hui Liao ◽  
Chi-Tai Wang

The chemical industry has sustained the development of global economies by providing an astonishing variety of products and services, while also consuming massive amounts of raw materials and energy. Chemical firms are currently under tremendous pressure to become lean enterprises capable of executing not only traditional lean manufacturing practices but also emerging competing strategies of digitalization and sustainability. All of these are core competencies required for chemical firms to compete and thrive in future markets. Unfortunately, reports of successful transformation are so rare among chemical firms that acquiring the details of these cases would seem an almost impossible mission. The severe lack of knowledge about these business transformations thus provided a strong motivation for this research. Using The Open Group Architecture Framework, we performed an in-depth study on a real business transformation occurring at a major international chemical corporation, extracting the architecture framework possibly adopted by this firm to become a lean enterprise. This comprehensive case study resulted in two major contributions to the field of sustainable business transformation: (1) a custom lean enterprise architecture framework applicable to common chemical firms making a similar transformation, and (2) a lean enterprise model developed to assist chemical firms in comprehending the intricate and complicated dynamics between lean manufacturing, digitalization, and sustainability.


Membranes ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 588
Author(s):  
Eiji Kamio ◽  
Hiroki Kurisu ◽  
Tomoki Takahashi ◽  
Atsushi Matsuoka ◽  
Tomohisa Yoshioka ◽  
...  

Forward osmosis (FO) membrane process is expected to realize energy-saving seawater desalination. To this end, energy-saving water recovery from a draw solution (DS) and effective DS regeneration are essential. Recently, thermo-responsive DSs have been developed to realize energy-saving water recovery and DS regeneration. We previously reported that high-temperature reverse osmosis (RO) treatment was effective in recovering water from a thermo-responsive ionic liquid (IL)-based DS. In this study, to confirm the advantages of the high-temperature RO operation, thermo-sensitive IL-based DS was treated by an RO membrane at temperatures higher than the lower critical solution temperature (LCST) of the DS. Tetrabutylammonium 2,4,6-trimethylbenznenesulfonate ([N4444][TMBS]) with an LCST of 58 °C was used as the DS. The high-temperature RO treatment was conducted at 60 °C above the LCST using the [N4444][TMBS]-based DS-lean phase after phase separation. Because the [N4444][TMBS]-based DS has a significantly temperature-dependent osmotic pressure, the DS-lean phase can be concentrated to an osmotic pressure higher than that of seawater at room temperature (20 °C). In addition, water can be effectively recovered from the DS-lean phase until the DS concentration increased to 40 wt%, and the final DS concentration reached 70 wt%. From the results, the advantages of RO treatment of the thermo-responsive DS at temperatures higher than the LCST were confirmed.


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