| Underwater vehicle is used as civil manned aircraft carrier in the field of offshore oil/gas industry and marine science, which provides survival living space for staff in long-term work. Its cabin is an airtight environment isolated completely from outside atmosphere. In this environment, the staff need a lot of consumable material and discharge many wastes which will limit working time and cruising ability of underwater vehicle, when it is dependent on ground support system in the cabin of underwater vehicle. Therefore, it is a vital mission to establish waste recycling system to convert waste gas and waste water to oxygen and clean water. Based on the research on waste recycling system of space station, this paper established a waste recycling system with eighty people processing capacity and examined their running performance according to the cabin’s characteristics.A integrated waste water treatment system was established to collect different waste water and to treat separately in the airtight space. Inside the cabin of underwater vehicle, the wastewater contained mainly urine wastewater、sanitary wastewater and condensation wastewater. The water quality and water yield of mixed wastewater varied greatly. COD and NH3-N were primarily from urine wastewater and sanitary wastewater, which changed periodically with people’s activities. COD ranged from3000to5000mg/L and NH3-N was79.5~129.3mg/L. This system employed MBR reactor to remove large amount of COD and NH3-N contained in wastewater for its high resistance to load shock. Over90%COD and NH3-N can be removed by MBR. However, there was little organic and nutrient elements in condensation wastewater. The effluents of MBR, mixed with condensation wastewater went by ultrafiltration、advanced oxidation technology、activated carbon filtration and reverse osmosis to remove turbidity and LAS as well as remaining COD and NH3-N. Results showed that the removal efficiency of COD and NH3-N was up to99.9%while turbidity and LAS were removed completely, indicating that effluent quality reached reuse standard.Integrated solid amine CO2absorption and enrichment-CO2methanation reduction system was established to realize removal and regeneration of CO2according to the total CO2discharge of80people. The CO2was up to56-80kg per day and the concertation should be controlled under0.5%for people’s health. About1000L air with0.5%CO2was put into the system every day. The solid amine absorb960L CO2in40mins with96.5%removal efficiency. CO2concentration was controlled at the level of0.2%. CO2methanation reduction system was based on Sabatier reactor, when CO2flow was1.40L/min maximum CO2conversion rate was about98.6%, indicating a good reduction performance. Reduction products, methane and water, could be reused respectively to energy support and oxygen regeneration system. Solid polymer electrolyte （SPE） oxygen regeneration system was established to meet oxygen demand according to oxygen demand and water resources. Oxygen concentration in the cabin of underwater vehicle will decrease with lapsed time. Based on energy and mass balance, the mathematical model was established to determine influence rule of current density、oxygen （hydrogen） pressure and temperature on system performance. Results showed that oxygen production could reach1976L/h with purity99.7%indicating that the performance could design requirements. Produced hydrogen could be regenerated in CO2methanation reduction system. Therefore, according to material flow, the solid amine CO2adsorption and enrichment system、CO2methanation reduction system and SPE oxygen regeneration system can be integrated to form a close loop system, but further study was needed to investigate material matching question.Wastewater/waste gas and recycling integrated technology was built in the study. Urine wastewater、sanitary wastewater and condensation wastewater. Mixed wastewater was collected and pretreated by MBR to remove most part of COD and NH3-N, then further to reduce LAS and turbidity by ultrafiltration. The remaining COD and NH3-N were removed by advanced oxidation technology and reverse osmosis. CO2was absorped and concentrated by solid amine effectively. Methanation reduction was carried out in Sabatier reactor producing oxygen. The waste recycling system in this study could dissolve water problems and oxygen demand in cabin of underwater vehicle. This could improve cursing ability of underwater vehicle and help improve establishment of waste recycling system of underwater vehicle. |
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