الفهرس 
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Abstract
The Sulfur dead stock problem is reported by many petroleum companies worldwide. Due to the continuous concern of these companies, this research is conducted to find a feasible solution to this existing problem to allow them storing the maximum quantity of sulfur residue in Silos. The element of sulfur takes the form of a sphere which has approximately a 3 mm diameter, is stored in a cylindrical storage silo, which is 44 m in diameter, with 20 m high walls and a conical roof. A conveyor system is used to load the sulfur to the top center of the Silo roof and fall inside. The Silo has four equispaced exit gates which are used to load the sulfur to ships.
The sulfur prills create “dead stock” which blocks the flow of sulfur from the exit gates and reduce the storage capacity of Silo. Hence a mechanical intervention is required to break down this sulfur dead stock to allow the flow and to get the maximum use of Silo storage capacity. The existing solutions are already used by these companies but they are very slow and not efficient.
The objectives of this work can be summarized in generating and evaluating ideas for a mechanical arm that scrapes the sulfur dead stock formed in petroleum industries and assists it to move towards the exit gates, building and verifying an FE model to be used in stress and deflection calculations. Designing and optimizing the proposed scraping system to have a maximum reach of 19 m and a minimum reach of 4.5 m under restriction of maximum stress. Many ideas had been suggested and studied to come up with the best solution and it was found that the pantograph mechanism is the best proposed one. A feasible pantograph system design was achieved and proved to be one of the most competitive solutions to the sulfur dead stock problem. A finite element model was built using ANSYS software to study the behavior of the target system and it was observed that the system weight is 4569 Kg, the maximum stress is located in one of the first steel pins not in pantograph links, and that the worst scraping position was reached when the system is in the downward position at = 90 degree and = 80 degree. The maximum stress in pantograph links is located at element 13 which is located directly after the mid joint of the first scraping link. The comparison between the measured and calculated stresses shows that the maximum error is 6.5 %, this should be considered in the design of the real pantograph system.
Kinematics and dynamics analysis was done Using ADAMS software to get links linear and angular velocities and accelerations and to design the driving system to maintain constant scraping speed at the system end effector. . The maximum magnitudes of linear and angular velocity of pantograph links are 0.082 m/s and 3.2 deg/sec consecutively but the maximum linear and angular accelerations have a maximum magnitudes of 0.015 m/s2 and 0.8 deg./s2 consecutively.
The cross sections dimensions of the real pantograph mechanism are determined using ANSYS software with respect to a maximum allowable stress of 142 MPa and a maximum system deflection of 25 cm. it was observed that a maximum stress magnitude of 127 MPa is located in one of the first steel pins (P10) and that a maximum system deflection of 24.86 cm is reached at the end effector of the scraping system.
A study on the constraint singularities was successfully done to determine and to avoid reaching the branching points of the mechanism, at which the system will stop moving and the stress will be increased dramatically