Design and Simulation of a Tank Floor Cleaning Mechanism for Mobile Robots used in Storage Tanks
02 Jul 2019-
TL;DR: In this article, a screw conveyor based sludge cleaning mechanism is proposed 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.
Abstract: 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.
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01 Feb 2021
TL;DR: In this paper, a screw-convex screw conveyor based system was proposed to scoop crude oil sludge from the floor of oil storage tanks using a worm drive and a bearing on both sides driven by a waterproof motor.
Abstract: This paper presents the design optimization and testing of a novel screw conveyor based system to scoop crude oil sludge from the floor of oil storage tanks This proposed new system consists of a screw conveyor mounted on a ‘C’ shaped casing with a bearing on both sides driven by a waterproof motor through a worm drive A novel mathematical model is developed to help the design of a screw conveyor for a maximum amount of sludge scooping per turn, and numerical simulations are performed using computational fluid dynamics to visualize the flow of material particles in various possible designs of the system The proposed mechanism was 3D printed, and laboratory tests were conducted to quantify the amount of sludge removal by the different designs of the screw Optimized design of a mechanism screw with a radius ratio of 040 and a pitch ratio of 015 scoops up to a maximum of 588 kg hr of material at 110 rev min
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TL;DR: Hopkins et al. as discussed by the authors presented a conceptual framework that identifies risks posed by in-water cleaning compared with alternatives, including no management, and showed that the appropriate management option will depend on many factors, including the species present, the level of fouling, and the time a vessel spends in a recipient region.
Abstract: Hopkins, G. A., and Forrest, B. M. 2008. Management options for vessel hull fouling: an overview of risks posed by in-water cleaning. - ICES Journal of Marine Science, 65: 811-815.Hull fouling has been identified as an important pathway for the spread of non-indigenous marine species. However, the management of associated biosecurity risks has proven challenging. Left unmanaged, a fouled vessel can pose a biosecurity risk through the detachment and dispersal of viable material, and through spawning by adult taxa upon arrival in a recipient port or region. These risks can be managed effectively through the removal of the vessel to land for defouling (e.g. dry-docking). However, alternative methods are needed for small (e.g. recreational) vessels, as well as for large vessels fouled outside their dry-docking schedule. Among the various treatment options, in-water cleaning is relatively common, although some countries have placed restrictions on this method because of perceived biosecurity risks. Here, we present a conceptual framework that identifies risks posed by in-water cleaning compared with alternatives, including no management. Decisions on the appropriate management option will be influenced by many factors, including the species present, the level of fouling, and the time a vessel spends in a recipient region. It is important that any regulatory changes regarding in-water defouling be supported by relevant research that quantifies the risks associated with the various management options.
53 citations
"Design and Simulation of a Tank Flo..." refers background in this paper
...While examining the tanks, crude oil sludge as a built-in material on an oil tank floor creates a problem by sticking to the robot, reducing the adhesion between the robot and the tank floor, affecting the camera vision and the locomotion of the robot in the oily environment [9, 10]....
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TL;DR: A survey of different technologies used for underwater cleaning and the available underwater robotics solutions for the locomotion and the adhesion to surfaces is presented.
Abstract: Underwater robots are being developed for various applications ranging from inspection to maintenance and cleaning of submerged surfaces and constructions. These platforms should be able to travel on these surfaces. Furthermore, these platforms should adapt and reconfigure for underwater environment conditions and should be autonomous. Regarding the adhesion to the surface, they should produce a proper attaching force using a light-weight technics. Taking these facts into consideration, this paper presents a survey of different technologies used for underwater cleaning and the available underwater robotics solutions for the locomotion and the adhesion to surfaces.
52 citations
"Design and Simulation of a Tank Flo..." refers background in this paper
...The most common failure mode in above-ground storage tanks (AST) is stress corrosion along the welding seams of the steel plates or the destructive process leading to pitting or even complete section loss, as oil leaks from the tank enter the soil and pollute the environment [4,5]....
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26 Jun 2010
TL;DR: In this paper, a new oil storage tank sludge cleaning robot system is designed for performing cleaning work instead of manual cleaning that is characteristic of low safety, low efficiency, long time and environmental pollution problems.
Abstract: Aimed at tackling the disadvantages of conventional oil storage tank sludge cleaning operations, a new oil storage tank sludge cleaning robot system is designed for performing cleaning work instead of manual cleaning that is characteristic of low safety, low efficiency, long time and environmental pollution problems. The robot system consists of robot, suction pump, hydraulic pump station, remote control center, windlass and so on, amongst them the modular structures have been adopted in the robot, which makes it possible to assemble all subsystems in the tank after having put them into the tank through a narrow manhole; Based robot motion characteristics analyzed and discussed, matching the track, hydraulic motors and other key components; based on finite element analysis and design of the shoveling, high-pressure water jet and mechanical shoveling so as to clean the polymorphic sludge effectively. The system tests in the Shengli Oil Field has shown that the oil tank sludge cleaning robot is able to perform cleaning operation in adverse oil storage tanks effectively, safely and reliably by utilizing hot industrial waste water jet under high pressure.
17 citations
"Design and Simulation of a Tank Flo..." refers background or methods in this paper
...A few sludges - cleaning robots has been developed with a bucket to shovel the sludge (as shown in Figure 1) with a high pressure water nozzle to clean the wastewater and collected with a suction tube attached to the robot [11,12]....
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...Figure 1: Photograph of a physical example of a sludgecleaning robot based on shoveling mechanism [12]....
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16 Mar 2015
TL;DR: In this article, the results of quantitative and qualitative analyses of oil obtained from crude oil tank bottom sludge (COTBS) generated from Azzawiya oil refinery in Libya were presented.
Abstract: In this work we present the results of quantitative and qualitative analyses of oil obtained from crude oil tank bottom sludge (COTBS) generated from Azzawiya oil refinery in Libya The aim of the study was to recover and evaluate oil from waste oily sludge and to compare it with parent oil (Hamada crude oil) in order to assess the commercial potential of recycling the oil The benefits would be two-fold, firstly to improve oil utilisation efficiency and secondly in reducing the environmental contamination associated with the petrogenic hydrocarbon industry Oily COTBS and extracted oil were characterised and key properties were measured including water and oil content, light and heavy hydrocarbon content, solid content and organic matter content for COTBS and water content, density, specific gravity, API (American Petroleum Institute) gravity, viscosity, salt and ash content for the extracted oil Solvent (hexane) extraction confirmed that the oily sludge contained 4208% (± 11%) oil composed of light hydrocarbons (307 ± 007%) and heavy hydrocarbon (693 ± 04%) fractions The water and solid contents were 29% (± 02%) and 5502% (± 06%) respectively The properties of the recovered oil were assessed; gas chromatograph spectrophotometer (GC-MS) results indicated that the oil contained 139 different hydrocarbon fractions with a total petroleum hydrocarbon (TPH) concentration of 29,367 mgkg-1 and a polycyclic aromatic hydrocarbons (PAH) concentration of 11,752 mgkg-1 Several parameters of the oil were measured and compared to the parent oil (Hamada crude oil) including density, specific gravity, viscosity, salt and ash content The API of the extracted oil (3303) was lower than the parent oil (388) due to a reduced light hydrocarbon (LHC) content TGAFTIR hyphenation shows both mass loss of hydrocarbons— low, medium and high molecular mass over a range of temperatures between 60°C and 450°C crude oil extract exhibited a non-Newtonian behaviour (shear thinning) for the shear rate sweep between 10 and 500/s dynamic shear rheology data showed that the extracted oil exhibit more like a solid than liquid Overall the findings of the study confirmed that COTBD has a significant amount of oil similar in properties to Hamada crude oil This large amount can be reclaimed and recycles Depending on this essay, a commercial process could be performed which in parallel will reduce the environmental contamination with hydrocarbons
16 citations
"Design and Simulation of a Tank Flo..." refers background in this paper
...Crude oil tends to separate into heavier and lighter hydrocarbons inside the storage tanks, and the at rest environment of the tank allows heavy ingredients of the oil to sink naturally according to their weight, to stick to the tank floor and to form a thick layer at the bottom of the tanks [2]....
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TL;DR: In this paper, the results of experimental studies into various methods of measuring sludge volume and its 3D spatial distribution using a base of data received from the inspection of more than 30 storage tanks of different types: external floating roof, internal floating roof and fixed roof.
Abstract: This article describes the results of experimental studies into various methods of measuring sludge volume and its 3D spatial distribution using a base of data received from the inspection of more than 30 storage tanks of different types: external floating roof, internal floating roof and fixed roof. The advantages and disadvantages of making measurements with existing methods are discussed, including the problem of accuracy. Numerous examples of tank survey results are presented.
14 citations
"Design and Simulation of a Tank Flo..." refers background in this paper
...Some amount of water is always present in crude oil, and additional water comes from condensation in storage tanks [1]....
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