Proposing a new solution for marine debris by utilizing on-board low-temperature eco-friendly pulverization system

Dong-Ha Lee,Sungkyun Park,Dong-Ha Lim,Seul-Kee Kim,Jeong-Dae Kim,Pung-Keun Song,Jae-Myung Lee,Gyung-Min Choi,Buhyun Youn,Jeong-Hyeon Kim,Jeong-Eun Oh,Jung-Kwan Seo,Hee-Tae Kim

doi:10.1038/s41598-021-03757-z

Dong-Ha Lee, Sungkyun Park + Show 11 more

Open Access

https://doi.org/10.1038/s41598-021-03757-z

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Abstract

Developing an effective and efficient recycling process for marine debris (MD) is one of the most urgent issues to maintain environmental sustainability on Earth. However, restricted storage capacities and secondary pollution (e.g., microbial adhesion, putrefaction) limit the proper MD recycling. Here, we proposed a complete eco-friendly low-temperature MD pulverizing system that utilizes excessive liquefied natural gas (LNG) cold energy (LCE) in an LNG propulsion ship to improve the efficiency and effectiveness of MD recycling. The prototype design of the low-temperature pulverization (LTP) system showed that consumable refrigerant (liquid nitrogen) up to 2831 kg per hour could be substituted. Furthermore, with a 20% ship output, 1250 kg of MD could be treated with 363 kg of additional refrigerant. In addition, LTP systems utilizing LCE could increase the storage capacity by more than 10 times compared to bulk MD while minimizing the required energy consumption. To determine the feasibility of LTP for MD recycling, four types of plastics obtained from actual MD from a coastal area in Busan, Korea were classified and tested.

Highlights

This study demonstrated a prototypical concept for an eco-friendly low-temperature MD pulverizing system that utilizes the cold energy from an LNG-powered cleaning ship
The energy source for the LTP is mostly from excessive cold energy from LNG propulsion ships, which are essential for the upcoming low- C O2 emission requirement
The energy conversion efficiency and optimal system configurations in designing an LNG-powered cleaning ship can be improved with technological development

Summary

Introduction

This study demonstrated a prototypical concept for an eco-friendly low-temperature MD pulverizing system that utilizes the cold energy from an LNG-powered cleaning ship. Typical cleaning ships used these days have a limited loading efficiency due to the low bulk density and larger volume of MD. The proposed concept can collect MD in the oceanic region because the MD loading capacity increases by more than 10 times through LTP and compression processes.

Results

Conclusion