Design and simulation of a tank floor cleaning mechanism for mobile robots used in storage tanks

Oily sludge on the floor of the tank is a significant problem for petrochemical industries and floor inspection robots. Oily sludge is a hazardous material containing a complex mixture of hydrocarbon, water, sand, and minerals deposited on the floor of the oil storage tanks. Sludge accelerates corrosion, reduces storage capacity, sticks to floor inspection robots and disrupts further tank operations Industries have started deploying robots in a tank to automate and replace the hazardous manual tank tasks. This paper presents the design of a screw conveyor based sludge cleaning mechanism to clean the sticky sludge from the floor of aboveground oil storage tanks and interface effectively with tank inspection robots to perform cleaning and inspection synchronously. The cleaning mechanism consists of a screw conveyor mounted on a ‘C’ shaped case with a bearing on both sides, a waterproof motor connected to the screw conveyor with a worm-wheel gear. A Rheometer is used for measuring sludge properties to understand its flow behavior. Computational fluid dynamics (CFD) based numerical simulation is performed to visualize the flow of oily sludge through the proposed cleaning mechanism.