Catalyst Loading System for TEDA Reactor
Submitted On: 12/12/2006
Prepared for Air Products by: Daniel Brisach, Nick Dobies, Laura Elliott, Chris Reed, Janessa Smith
Sponsor: Phil Shodder, Air Products – Paulsboro, NJ 2
Table of Contents Executive Summary...... 3 Introduction...... 4 Work Accomplished...... 4 Concept Description...... 6 Concept Subsystems...... 6 The Loading Mechanism...... 6 The Rail System...... 7 Cable and Pulley System...... 8 Tipping Mechanism...... 9 Prototype...... 11 Results of Prototype Testing...... 13 Concept Validation and Hazardous Operations Review...... 13 Benefits to Sponsor...... 13 Cost Analysis...... 14 Path Forward...... 14 Conclusion...... 15
Figures Figure 1: Final Design...... 3 Figure 2: Rails and Supports...... 7 Figure 3: Locking Mechanism...... 8 Figure 4: Cable and Pulley System...... 9 Figure 5: Tipping Mechanism...... 10 Figure 6: Prototype Design...... 12 Figure 7: Prototype Testing...... 12
Tables Table 1: Priorities...... 5 Table 2: Constraints...... 5
Appendices Appendix A: UDesign Wants, Metrics, and Concept Selection……………………………….. 16 Appendix B: Failure Analysis for Rail, Structure and Cart Four-bar Linkage .……………….. 23 Appendix C: Design Package ………………………………………………………………….. 34 Appendix D: Bill of Materials/Cost Analysis …………………………………………………..46 Appendix E: Hazardous Operations Review ……………………………………………………47 Appendix F: Safe Work Practice ………………………………………………………………..48 Appendix G: Gantt Charts ………………………………………………………………………52 3
Executive Summary
Air Products, in conjunction with the University of Delaware, presented our senior design team with the challenge of updating an existing process in their Paulsboro, New Jersey plant. Currently, the Paulsboro plant manufactures a well-known TEDA catalyst that is sold to polyurethane foam manufacturers to produce foam for use in insulation and automotive parts. Part of the process to make TEDA requires a critical chemical reaction to take place. This chemical reaction requires its own catalyst: strontium hydrophosphate. This catalyst is loaded into a reactor to allow steam to flow through and interact with the catalyst facilitating the chemical reaction required. The current process to load the aforementioned catalyst into the reactor is the subject of this report and the presented design problem. The current method of loading the catalyst into the reactor requires 55 gallon drums to be opened and bucketed with a standard 10 quart plastic bucket into the reactor. The entire process takes about 36 man hours and the loading limit is eighteen drums. Air Products would like a more ergonomic, faster, and safer process of loading the catalyst into the reactor. This will reduce the risk of injury, reduce the reactor downtime, and reduce the number of labor hours required for the process. Therefore, the design problem to be solved is to develop a more effective way to load the catalyst into the reactor. The chosen solution for this given design problem is a cart and rail system. The first step is to load the drum of catalyst into a cart. Then the cart would be powered along the rails to the reactor mouth, at which point it would be dumped into the reactor. After all of the catalyst has been removed from the barrel, it will travel back down the rails. At the base of the reactor, the empty barrel would be unloaded and a full barrel would be loaded to begin another cycle. Ultimately, this design will decrease the man hours needed to load the catalyst, saving money for Air Products. More importantly for Air Products, this process will be safer for the workers involved. One of our main safety features is a series of safety switches for the smooth operation and full automation of the system. Furthermore, the new process will reduce the need for repetitive motion and reduce the number of pinch points in the system. The chosen solution will be faster, safer, and more effective at delivering catalyst to the reactor than the current process.
Figure 1: The final design is a cart, rail and hoist system to deliver barrels of catalyst to the reactor 4
Introduction
The mission of this project is to develop a more effective way for operators to load the catalyst, used for the production of TEDA, into the main reactor. The current method for loading the catalyst is to bucket drums of catalyst into the reactor. The project scope is to design a system to load the catalyst into the reactor and to develop a drum transport system. The cable and rail system will start from the second floor near the reactor mouth or the first floor. In order to ensure an effective solution to the current challenge the team met with Air Products to build a list of wants (priorities) for the solution. Once this list of wants was compiled, metrics and target values were assigned to each want as a means of identifying whether or not a particular design idea would be an effective solution. The details of this process are contained in Appendix A. The information found in the Appendix contains safety standards of the building, information from Sponsor meetings, and information found from current applicable benchmarks. After reviewing the wants, metrics, and target values, the team evaluated initial concept ideas against the various measures to determine which concepts were indeed viable solutions. The cable and rail system was chosen as the best solution to the problem given the wants and constraints of the project. After much research and iterations of concept design the cable and rail system was modified to fit Air Products needs. The selected concept of the cable and rail system will provide some instant benefits to the sponsor. The concept of an automated system immediately improves the ergonomics of the procedure by eliminating the possibility of back strain and the need for repetitive motion. Inherent in the design as well is a substantial decrease in the amount of time taken to unload the barrels into the reactor due to the fact that they will be dumped all at once instead of bucketed. Furthermore, safety considerations will be constantly checked to insure that the selected concept is safer overall and contains less potential for employee injuries. These additions will improve the overall process making it safer and more ergonomic for Air Products and its valued employees. This report will detail the design of the system, explain its advantages, and then recommend a plan for implementation.
Work Accomplished
While developing the current concept, the team encountered many design constraints and issues not previously foreseen. Ultimately, the cable and rail system concept was selected because it was better at meeting or exceeding the target metrics associated with the wants above than all of the other contenders. Early on this system was rejected for being too expensive and difficult to implement. Our contingency concept was a traveling hoist and I-beam, which would lift the drums through a whole in the second floor up to the reactor and then translate across an I- beam to the reactor mouth and tip the drum contents into the reactor. It was learned shortly after this second concept was selected that the importance of keeping the catalyst whole, the 2 nd highest priority, had been an assumption and was not as important as originally thought. This changed our prioritized list of wants, but effectively only eliminated the need for a device to let the catalyst down gently into the reactor. Consequently, the team continued development of the hoist and I-beam system while keeping the cable and rail system as a contingency plan. The hoist and I-beam concept was promising at first. The current change-out practice includes the system, and it works well though its scope is limited. Unfortunately, the I-beam system would not fit within the space provided, 5
so it would require that building supports be removed. The system would be expensive and difficult to install, as well as require a professional civil engineer to approve the removal of building supports and the installation of the I-beam. Between the professional consultation and the Hazardous Operations evaluation process, the process would be long, expensive, and arduous and take much longer than the remaining six weeks. Because the list of wants and metrics had been revised, we could revisit some of our earlier concepts. Among them, the most promising was the screw conveyor with a drum dumper, located on the ground floor. We compared its qualities to our revised list of metrics with good results. The screw conveyor would fit into the space provided, requiring only that a relatively small hole be cut in the floor, less than 12 inches in diameter. The hopper and motor would be permanently attached in a corner of the building where it would not interfere with other operations. The drum dumper would be portable and could be stored in a convenient place. The system would be relatively simple to implement, requiring only that a hole be cut in the floor and the assembly and installation of the machine. The cost of the system in time and money is considerably less than the I-beam system. Degradation of the catalyst is still a concern, but the vendor will be able to test a sample of our catalyst. Unfortunately, upon speaking with Air Products, it was concluded that this was also not feasible due to maintenance upkeep issues and static friction concerns with the catalyst that could possibly start small fires.
Table 1 Table 2 Priorities Constraints
Ergonomic Safety Fast Changeover Reactor room geometry 3. One Man Operation Electrical rating Low Complexity Floor weight limit Ease of Repair Air pressure (pneumatics) These developments led the team back to the first concept of the cable and rail system. The concept was tailored to fit the Air Products needs and was changed to a local system located only at the reactor. The team found that this was the best solution due to the geometric constraints of the reactor room. The cable and rail system kept the transportation of the drum to the second floor the same for reasons previously stated. This concept still meets the Air Products needs and satisfies the project scope and goals. The sponsor put the concept through a “Haz-Ops” process that identified the weak areas of our design that we will take special care to address. Given all the previously stated work to date, it is important to note our timeline which was kept in an organized manner as a Gantt chart. The actual Gantt chart can be found in Appendix G. In the first part of the project, known as phase 0, the team compiled as much information as possible about the assigned design problem and Air Products needs. During this portion of the project the team kept to the timeline and completed the tasks in a timely manner. In the following phase of concept development, the team also remained fast to the timeline but ran into some slight setbacks with the cost estimate. In phase 2, the concept development phase, the team encountered major setbacks as stated above. At the conclusion of this stage in the project a concept had been selected: the cable and rails. However, little detail work of the concept or prototype design was completed. This forced our team to essentially complete two phases in remaining time. In order to accomplish this, tasks were split up among the team 6 members, which allowed us to work more efficiently to meet our goals. By the last week of the project, the team was back on schedule with a complete design and commencing prototype testing.
Concept Description
The design solution of the cart and rails is a relatively simple local rail system located at the mouth of the reactor. Essentially, the catalyst drum will be loaded into the cart and the cart will travel along the rails to the reactor mouth before it is emptied and returned to the starting position. The cart itself contains straps and a locking funnel lid to insure security and reduce catalyst loss during the transfer of the drum to the reactor mouth. Once the cart is loaded and the drum is secure, a system of pulleys powered by a two-way winch will be activated by the operator to lift and translate the cart and drum into a horizontal position above the reactor mouth. When the drum is in position horizontally above the reactor mouth, the operator will then activate the pistons on the cart in order to pour the drum contents into the reactor. With the drum now empty, the piston will deactivate to lower the drum and the operator will then re-activate the winch to lower the drum and cart to the starting position. In essence there are four major systems to the design: the cart, the rails, the pulley and winch system, and the tipping mechanism. Each of the systems will be discussed in detail below as to the design specifics, engineering analysis, and overall satisfaction of the original wants of Air Products.
Concept Subsystems
The Loading Mechanism
The Loading of the Mechanism encompasses the time from when the drum is placed on the second floor until it is secured into the basket on the drum dumper cart. Once the fresh drum is unloaded onto the second floor, an operator loads the 55-gallon drum full of catalyst onto a specialized drum hand cart, which he or she then pushes over to the front of the drum tipper cart. From here, the operator sets the drum down, and removes the lid from the drum. The drum cone would then be attached using the collar belonging to the lid that was removed. The drum cone that was constructed for the prototype can be used for the full design. The operator then opens the safety gate in front of the drum cart. The opening of the safety gate triggers a proximity sensor that kills the air pressure going to the pneumatic controls of the design so nothing will function until the operator is clear of the drum and the gate is closed. With the safety gate open, the operator then uses the hand truck to push the drum inside the foot print of the drum tipper basket. He sets the drum inside the basket, making sure to fit the drum cone under the lip on the cart which would prevent the barrel from falling out the top. After wheeling the hand cart out of the way, the operator fastens the safety lanyard around the front of the drum to prevent the drum from falling forward and out of the basket when the drum is tipped. The operator then leaves the loading area, making sure to close the safety gate which resets all the pneumatic controls for the system. The main concerns for this subsystem when conducting the Hazardous Operations Review were that the drum would not be sufficiently secure during translation and tipping and that cart may operate while the operator is working on loading the drum. With consideration to 7 the first safety concern, the drum will be securely fastened within the basket via the drum cone locked in place on the top of the basket. However, as an additional safety consideration, a safety strap was added around the front of the catalyst barrel to prevent the possibility of the drum falling out when the drum is being tipped. The second safety issue was addressed by adding the proximity sensor to the gate around the cart. Since the system is designed to “fail safe” the operator is kept safe from the drum translating because when the proximity sensor on the safety gate is tripped it shuts off the pneumatic controls locking the system in place.
The Rail System
The rail system is the foundation of the concept. The rails carry the cart that holds the barrel from the floor to the mouth of the reactor. The rails are made of C3x6 structural steel C- channel that has been pulled and bent into a 90º bend. They are supported by a framework of welded steel hollow square tubes.
Figure 2: The rail and support subsystem of the design
As mentioned previously, the rail system was the best solution because it best met the wants and constraints of Air Products. The rail subsystem is much more ergonomic than the current means of delivering the catalyst to the reactor mouth, as it saves the operator from any repetitive bending motion. This part of the system is faster than emptying drums by hand with a bucket and only one man is required for this part of the process. The rail is low in complexity, and it would be easy to repair should anything happen to it. The rail was designed to last for the life of the catalyst reactor under typical working conditions, but should anything catastrophic occur, the damaged part could be cut out and a new piece of steel welded on. The risks of the rail system are few, as the complexity is low. The rail could deform, break, or fall/roll over. In any of these cases, the 450-pound drum could fall, causing damage and/or injury. We designed the rail so that it cannot deform or break under typical working conditions. A static failure analysis of the tendency to buckle, bend or twist shows a safety factor of 3.8, which means that the strength of the rail is 3.8 times the strength required. The failure analysis also showed that the cross-section would not deform significantly or permanently. The cyclical failure analysis showed that the rail would last infinitely under the loading conditions presented by the cart and drum. The failure analyses can be found in Appendix B. The support structure below was designed against buckling and rolling over. The 8 analysis of the supports demonstrated that the steel tubing would not buckle under the weight of the rails and cart. The supports are also wider than the track and either bolted or welded to the floor. In the event that all of the weight was on one rail, the structure would not tip. Other concerns about the rail system are that the cart could fall out the end of the reactor, or that the cart could move about while its contents are flowing into the reactor. The rails will be capped on the end with welded steel, as there is no need for removal of stoppers. The cart can be removed from the rails while it is vertical, resting on the ground, and unloaded. There are staggered slots in the C-channel that the cart wheels can fit through. The cart would be lifted about an inch to pull the bottom wheels out of the lower slot, and then the other cart wheels could be maneuvered out of the other slots. A locking mechanism would allow the cart to be fixed in place before the tipping begins. A metal bracket would be attached to the cart and a hole would be drilled in one of the supports so that a pin could be pushed through both holes.
Figure 3: The operator pins the cart to the supports to lock it in place before tipping the barrel
Cable and Pulley System
A pneumatic winch is used to move the cart. Two cables are wrapped in opposite directions around winch’s shaft. A cable is attached to each end of the cart. When the winch’s shaft is rotated in one direction, the cable pulls cart up and to the right. When winch’s shaft is rotated the other direction the cable pulls the cart to the down and to the left. The winch can be purchased from Jeamer Winches for about $4000. Sheaves, Inc sells the two pulleys: Pulley 1 is stock and only costs $10, Pulley 2 is custom and would cost between $40 and $50up to $100. The fairlead is $36 45 from Moose Utility DivisionWarn. The roller is Model number 3530S-31 and is available from Roach Conveyors for $80. 9
Figure 4: The winch pulls the cart along the rail system
This winch and cable system is very ergonomic for one operator. The raising and translation method occurs smoothly and quickly, therefore helping to keep the catalyst whole and have a high speed of changeover. Structurally, this system is designed with a high level of safety. The main risk factor is the alignment of the cable. The cable going from the winch to Pulley 1 is aligned by a roller fairlead. Keeping tension in the cable helps prevent it from moving out of place. In order to accomplish this, the shaft of Pulley 2 is allowed translate horizontally and there are springs on either side. There is also a 31” wide Roller in this system, which virtually eliminates the need for accurate alignment between itself and the cable.
Tipping Mechanism
The barrel is tipped by a parallel set of 4-bar linkages. Both of these linkages will be driven by pneumatic actuators. The decision to use a 4-bar linkage was arrived at when it was revealed through calculation that the greatest angular displacement direct actuation could achieve would not be adequate. Note that direct actuation is the term used for the scenario in which the piston and barrel would share a common joint. The geometry of the 4-bar mechanism was designed using graphical position synthesis. Once the link configuration and geometry was chosen, a static stress analysis was performed to allow the input and reaction forces to be determined. Some minor corrections, or better design decisions, were made to allow for the design to be compact, have a high safety factor, and be efficient.
Risks/Validation: The analysis of position was relatively simple and required no over-simplifications or gross assumptions to be made. Thus there is great confidence that the mechanism will travel the correct path. However, modeling and analyzing the dynamics of the system proved to be rather difficult. A dynamic analysis would require that we know or assume the angular acceleration of the input link as a function of position or time. This would not be very difficult to calculate if the speed of retraction in the pneumatic cylinder were known. However, this information is not readily available and would require intensive calculation to approximate accurately. The primary objectives of performing the dynamic analysis would be to determine the input force 10 necessary to drive the system and to size the links, which would be a result of a stress analysis based on the reaction forces present within each link. Since the input force would determine the piston selection, it would be difficult to include the motion characteristics of this unknown piston size into the dynamic analysis. This is the point in which it was decided that some simplification must be made in the analysis to be able to size the piston and links.
Collapsed Extended
Figure 5: Tipping Mechanism
The major simplifying assumption that was deemed plausible and secure was that the mechanism would be driven relatively slowly, so slow that the problem may be considered static. This of course would neglect the force needed to drive the inertia of the system and friction present at all of the joints. The friction at the joints is assumed to be relatively low because of the presence of bearings. Also, since the mechanism would be driven at a slow rate, the angular accelerations would be very small (close to zero). In a case such as this, it would not take very much force to overcome the effects of inertia. To allocate for the small, but unknown, components in the analysis, it was decided to dedicate 20% of the input force toward them. Once this decision had been made, it was then straightforward to go forth with the static analysis and find the input and all reaction forces within the system at any position within its range of motion. The static analysis was performed in Matlab so that the position of the input link could be varied and the forces within the system could be determined at each respective position. Once the preliminary results were obtained, they were ranked against what was intuitively expected. The input force as a function of position was the parameter chosen to be checked. The input force would be expected to be at a maximum in the initial configuration and be nearly zero when approaching the toggle position. Also, the shear component of the third coupler link was checked to make sure that it equaled zero at all positions (which is a must since this link is classified as a 2 force member). This behavior was generated by the simulation, yet there was still some skepticism of the accuracy of the magnitude of force that had been calculated. This skepticism was then relieved through comparison to a hand calculation of the input force needed to keep the system static in the initial configuration. After the reaction forces were calculated and confirmed, they were then resolved into the normal and shear directions. Once this information was obtained, a stress analysis was performed for each link. For the input link (link 2), a conservative assumption was made to aid in simplifying the analysis. This was the assumption that the link would at worst be subject to a cantilever loading. This is not how the beam would be loaded in practice but it is widely accepted as being a conservative estimate in most bending scenarios. So, the input force was used as the load value 11 and the beam was considered to be a cantilever loaded at its full length away from the wall. It should also be noted that another conservative estimate that went into the analysis of this member was that the recess cavities intended for the bearings were assumed to be through holes. Then the static and fatigue safety factors could be calculated for their particular geometry. The coupler link was analyzed in a similar fashion to the input link. The major difference mainly being that since the member is known to be a truss, it can safely be assumed that the member would only be subject to axial (normal) stress. Again, the stress concentration factor was calculated for through holes with the diameter of the respective bearing recess diameters. The final members (the barrel nest and the ground link) entailed the most presumptions of all. The ground link (cart frame) consists of a rather complex geometry and loading configuration to analyze. The reaction forces acting on the frame as well as the piston force that acts on the frame were determined previously. The forces that act within the various members of the frame are not as easily obtained, if possible for that matter. So, it was assumed that the longest member of the cart would be loaded in a cantilever fashion (as was done previously in the input link analysis) with the maximum value of the forces that could possibly act on it throughout the mechanism’s range of motion. The barrel nest entails the greatest assumption. No formal validation was performed for the fourth link (the barrel nest). The design of the nest was delayed and there was not proper time to perform an engineering analysis. However, intuition would hint that a plate loaded in shear is rather strong. The only precaution taken in sizing the barrel nest was to make it at least the thickness of a barrel’s wall, which is approximately 1/8”. The final question to be addressed was how many cycles could be expected of the mechanism as a whole or better yet the inverse of this question; how large or strong should the linkage components be in order to expect an infinite life of the mechanism? This would be a difficult problem to solve and would only have the value of determining the smallest geometry acceptable. It is much easier to assume a cross section that seems intuitively adequate and calculate a safety factor for this choice of geometry. So, that is the approach that was undergone. Alternating and mean von Mises stress were calculated for the input and coupler link then used in the correct context to determine the safety factor for each linkage. A conservative corrected theoretical endurance limit was calculated by making conservative assumptions where needed and the reliability factor was for a 99.99 percent reliability. In summary, the fatigue safety factors were calculated for each component within the sub-system. The worst case loading occurs in the input link, since it is subject to a bending moment. Here, the factor of safety was determined to be approximately 1.8. This value seems adequate, but it would be nice to have some sort of idea of how sensitive this value is to geometry. So, to determine this sensitivity, this particular safety factor was studied for varying cross sectional dimensions (keeping the cross section shape constant). It turns out that the value varies pretty drastically for a small fluctuation in either of the cross section dimensions. Thus it was decided that the original choice of cross section was the smallest choice that could confidently be implemented. Also, the cross sectional dimensions of the preliminary choice correlate to a standard size of metal.
Prototype
The aspect of the design that represented the biggest concern to Air Products was the flow of the catalyst from the mouth of the drum cone into the manhole of the reactor. The 12 catalyst used is classified as a bulk solid. Bulk solids are unique in that their flow properties are neither representative of fluid nor solid flow. The two main concerns addressed by the prototype are that the flow of the catalyst can be directed into the manhole without spilling the catalyst, and that catalyst does not clog the mouth of the drum funnel preventing adequate flow. It also provided an approximate time for the emptying of the drum as well as determined the maximum tilt angle necessary to dispense the entire barrel of catalyst. The purpose of our prototype was to reduce this risk andd illustrate the pouring of the catalyst. Figure 6 shows our planned method for achieving this goal. It was built out of 2”x4” and 2”x8” lumber and ¾” plywood. The drum cone was fabricated by a sheet metal working company out of 1/8” sheet metal that is welded to the rim of a drum lid and attached to the barrel with a collar.
Figure 6: The prototype design is a tipping table to test the catalyst flow into the reactor mouth
For the test we tipped a barrel of catalyst onto its side and lifted it up to the table using webbing and a forklift. Once the barrel of catalyst was on the table, two straps were used to hold it in place. The surface of the table is covered with a rubber mat as to provide ample friction to prevent the barrel from slipping when tipped. A hoist was hooked to an eyehook on the left hand side of the tabletop. Raising the hoist caused the tabletop and barrel to rotate about the hinges on the right hand side of the table. The barrel on the ground represents the manhole of the reactor and was offset 11° from the ground with 2”x4” shim underneath one side of it. The prototype was designed to maintain accurate actual design distance from the barrel to the axis of rotation, and careful detail was taken to ensure that the barrel is aligned accurately from the end of the table. After purchasing our materials, it seemed logical to make certain changes to the design of the prototype. We increased the structural integrity and ease of assembly. These changes can be seen in the picture. The prototype cost a total of $522. This small cost is worth it, because it helped validate our design. Also, the bulk of the cost of the prototype was the drum cone, which can be used in the actual process instead of ordering a new cone and collar for $1400.
Figure 7: The prototype shows that all catalyst falls into the reactor 13
Results of Prototype Testing
Figure 7 above depicts the actual testing of the prototype. The entire barrel of catalyst was successfully emptied into the second barrel, representative of the manhole on the reactor, with no quantifiable amount of waste being generated. We were only able to conduct one test because of the limitations. Upon review of video footage taken during testing, the main stream of the catalyst appeared to not come within 4 inches of the front lip of the barrel and 6 inches from the back of the barrel. The testing also proved the optimum distance from the end of the rails on the actual design to the front lip of the reactor manhole. While a majority of the barrel was dispensed by 70 degrees of rotation, the testing determined that a full 90 degrees of rotation would be necessary to empty the entire barrel. As the pouring did not start until about 20 degrees of tilt was attained, it was extrapolated that the drum would be able to translate the rail path to the mouth of the reactor without the presence of a valve on the mouth of the drum cone. Only significantly high deceleration values would be capable of emptying catalyst during rail translation. The winch used on the system is not capable of producing this amount of deceleration before the end of the track, where spillage would fall into the reactor mouth.
Concept Validation and Hazardous Operations Review
Our concept was reviewed by the “Haz Ops” process, which identifies the riskiest elements of the design and suggests solutions. We have done our best to address all of the concerns raised by this process. Potential risks that were identified include the drum falling on the operator, sparks causing a fire, injury by operator having finger/hand/arm pinched, loss of control of the winch or actuators if air pressure is lost, the catalyst not pouring into the reactor properly, lack of procedure, and improper maintenance. Many of these risks can be easily diminished. For instance, our system will use only pneumatic machinery and there will be a grounding strap attached to the barrel so that it is always grounded and there is no opportunity for sparks. Opportunity for operator injury is reduced by putting the controls for the system at a distance, so that the operator cannot touch the equipment and operate it at the same time, and by putting a safety gate around the system. The sponsor expressed that the largest uncertainty in our design was presented by the pouring of the catalyst, which is what we modeled. For a complete list of the Haz-Ops findings and our solutions, please see Appendix E.
Benefits to Sponsor
From the onset of the project, the sponsor has continued to express that the main reason they are exploring improvements in this area is safety. Improved safety, from their standpoint, encompasses anything from jobsite injury, such as loosing a finger, to degenerative injuries, such as back injuries caused by repetitive motion. The proposed process improves both of these areas considerably. The ergonomics of the new process eliminate repetitive lifting requirements for the operators, such as the scooping of individual mop size buckets out of the 55 gallon drum. Additionally, there will be a safety guard placed around the entire system. The safety guard will have gates with proximity sensors that will shut off pneumatic devices when the gates are open. Furthermore, every necessary component for the operation of the system is designed to “fail safe”, meaning that if pressure is 14 lost or another problem arises, the machine will automatically return to a safe position. The last major precaution taken when dealing with operation of the proposed concept is that the controls for the system are placed ten to fifteen feet away from the cart and rails, thus preventing the operator from interacting with the cart during translation and tipping. Proximity sensors will also be used to sense when the cart is in the raise position or in the lowered position. The other main area that the sponsor was hoping to improve upon with this project was the amount of time it takes to empty a barrel. The current process takes about 36 man hours. After much discussion with the sponsor, a target value of 12 man hours was set as acceptable. The concept design would be capable of charging the reactor in less than 9 man hours. This is an improvement on the target value. The process is very close to a one man operation with two men still required to raise the barrels of catalyst to the second floor. The amount of time save not only saves the plant money by decreasing reactor downtime, but it also frees up the operators, who are spread thin at the Paulsboro plan, to work on other tasks in the plant. The total cost of design implementation was within the $15,000 budget provided by Air Products. The design also met other metrics, including: class 1 division 2 electrically rated components, no part specific tools required, no specific training required to operate or repair the design, and it is relatively simple to operate both mentally and physically. The sponsor was very pleased with the proposed final design. They again expressed that increasing safety was the main driving factor behind the development of this project. They felt that the proposed design satisfied their requirements for this project.
Cost Analysis
The design that has been chosen and represented herein is the most economical solution that was discovered. This drove the system choices that were made at various stages throughout component selection. Although the design involves a fair amount of fabrication, the majority of the parts are readily available. The largest component of the budget would consist of the installation costs. There is also the need for a few other expensive items such as the winch and steel that would be used to fabricate the cart and rail systems. The budget is itemized by subsystems in Appendix D, where it is much easier to see the budget allocation.
Path Forward
The path forward for the sponsor given all the information of the current design is outlined below. The engineering calculations should be examined closely to ensure that our assumptions are correct and valid. Also, special consideration should be taken to analyze the cart strength, for instance, a finite element analysis on the linkage might be helpful. As far as the implementation of the rail and support system, they will need to be custom fabricated by an outside contractor. This cost has been factored into the cost analysis. It is also important to note that the cost can be reduced in this area by performing the work on-site, and there are other cost- saving steps that Air Products can take as they implement the design. One part of the process that was not fully addressed was the exterior hoist. One of the main complaints of the operators was that hoist was very slow in hoisting the drums up to the second floor. If Air Products seeks to improve that part of the process, our recommendation is to buy a new hoist to lift the drum to the second floor faster. As a team we did investigate the option of re-gearing the existing hoist, 15 but given the hoist model and make this was not possible. To make implementation of the design easier, we have included the contact information for companies that can provide services and equipment for the parts of our design that require custom work in our Cost Analysis and Bill of Materials in Appendix D.
Conclusion
We recommend that Air Products implements the design we have outlined above and detailed in the appendices. The design will improve the safety conditions of the catalyst change out process, save time for the operators, and reduce the reactor downtime for a reasonable cost. 16
Appendix A: Udesign Wants, Metrics, and Concept Selection
Final Wants Rate of Ranking Importance 1 Ergonomics 46.37 2 High speed of changeover 19.32 3 One Man Operation 12.54 4 Low complexity 9.83 5 Ease of Repair 6.64 6 Low cost 2.71 7 Reliable 1.42 8 Keep Catalyst Whole 1.15
Metrics Target Values Speed of Process 12 hours, 1 man Ease of Operation No Chance of Injury One Man Operation Yes Number of Pinch Points 0 Amount of Waste ## kg per barrel Stability of instrument Yes Force Required to Operate Limited to positioning of barrel Breakage of Catalyst Density or pellet diameter (bulk density) Weight of instrument complicated Footprint size Less than 8' x 8‘ or easily removable Electrical Rating Standards Cost of Implementation $4,000 Repairability <2 hours to repair, no special tools or training Reliability Fails less than once per 10 years Special Tools no Special Training to repair no Special Training to operate no Stability of catalyst drum in instrument Yes Resistance to Corrosion by catalyst and ambient conditions Yes Concepts Concept Descriptions 17 Current System Hand truck A slide B air pressure C sliding I-beam D tubular drag conveyor E vaccuum F auger G cable & rail Concept Selection Table Metric Information Conceptual Solutions Benchmark A B C D E F G H Metrics % Target value Speed of Process 18 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Ease of Operation 11 1 -1 1 1 -1 1 1 One man operation 11 0.2 0.2 0.2 0.2 0.2 0.2 0.2 number of pinch points 10 1 1 0.2 1 1 1 1 amount of waste 5 -1 -1 0.2 -1 -1 -1 0.2 stability of instrument 5 1 1 -1 1 1 1 1 force required to operate 5 1 1 1 1 1 1 1 breakage of catalyst 5 -1 -1 0.2 -1 -1 -1 0.2 weight of intrument 4 -1 -1 -1 -1 -1 -1 -1 footprint size 4 -1 -1 -1 -1 -1 -1 -1 electrical rating 4 0 -1 0 -1 -1 -1 0 cost of implentation 3 -1 -1 -1 -1 -1 -1 -1 repairability 3 1 -1 -1 -1 -1 -1 -1 reliability 3 0.2 -1 -1 -1 -1 -1 0.2 special training to repair 3 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Special Tools 3 0.2 0.2 0.2 0 0.2 0.2 0.2 special training to operate 2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 stability of catalyst drum 1 1 1 -1 1 1 1 1 resistance to corrosion 1 -1 -1 0.2 -1 -1 -1 0.2
Better than benchmark 6 4 2 5 4 5 5 Worse than benchmark 6 10 7 9 10 9 4 Same as benchmark 6 5 9 4 5 5 9 Unknown relationship Sum-Up 1 1 1 1 Score 0% 1.2 -5.0 -3.2 -3.2 -5.0 -3.0 2.8 Sum-Up Compared to benchmark: Symbol Value Better than benchmark b 1 Perform this check in a round robin fashion. Worse than benchmark w -1 Let the prevailing concept from one round be Same as benchmark s 0.2 the benchmark in the next! Unknown relationship u "0" 18 Concept Iteration Template Current Rank Concept ID. Concept Description 1 Best cable & rail 2 A slide 3 B air pressure 4 C sliding I-beam 5 D tubular drag conveyor 6 E vaccuum 7 F auger Concept Selection Table ID. G Benchmark A B C D E F Metrics % cable & rail slide air pressuresliding I-beamtubular dragvaccuum conveyor auger 0 Speed of Process 18 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Ease of Operation 11 -1 0.2 0.2 -1 0.2 0.2 0.2 One man operation 11 0.2 0.2 0.2 0.2 0.2 0.2 0.2 number of pinch points 10 -1 1 1 0.2 1 1 1 amount of waste 5 0.2 -1 -1 0.2 -1 -1 -1 stability of instrument 5 -1 1 1 0.2 0.2 1 0.2 force required to operate 5 -1 0.2 0.2 0.2 0.2 0.2 0.2 breakage of catalyst 5 0.2 -1 -1 0.2 -1 -1 -1 weight of intrument 4 1 0.2 0.2 -1 0.2 0.2 1 footprint size 4 1 0.2 1 1 1 1 1 electrical rating 4 0 0 -1 0 0 -1 -1 cost of implentation 3 1 0.2 -1 0 -1 -1 -1 repairability 3 1 -1 -1 -1 -1 -1 -1 reliability 3 0.2 0.2 -1 0.2 -1 -1 -1 special training to repair 3 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Special Tools 3 0.2 0.2 0.2 0.2 0.2 0.2 0.2 special training to operate 2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 stability of catalyst drum 1 -1 1 1 -1 1 1 1 resistance to corrosion 1 0.2 -1 -1 0.2 -1 -1 -1
Better than benchmark 4 3 4 1 3 4 4 Worse than benchmark 5 4 7 4 6 7 7 Same as benchmark 9 11 8 12 9 8 8 Unknown relationship Re-chk 1 1 2 1 Score 0% 0.8 1.2 -1.4 -0.6 -1.2 -1.4 -1.4 19 Concepts Concept Descriptions Current System Bucket A rail/track B drum dumper C turning device (Morse MFG)
Concept Selection Table Metric Information Conceptual Solutions Benchmark A B C D E Metrics % Target value Speed of Process 18 1 1 1 Ease of Operation 11 1 1 1 One man operation 11 0.2 0.2 0.2 number of pinch points 10 -1 -1 -1 amount of waste 5 1 0.2 1 stability of instrument 5 1 1 -1 force required to operate 5 1 1 -1 breakage of catalyst 5 0.2 0.2 0.2 weight of intrument 4 -1 -1 -1 footprint size 4 -1 -1 -1 electrical rating 4 0.2 0.2 0.2 cost of implentation 3 -1 -1 -1 repairability 3 -1 -1 -1 reliability 3 -1 -1 -1 special training to repair 3 0.2 0.2 0.2 Special Tools 3 0.2 0.2 0.2 special training to operate 2 0.2 0.2 0.2 stability of catalyst drum 1 -1 0.2 -1 resistance to corrosion 1 0.2 0.2 0.2
Better than benchmark 5 4 3 Worse than benchmark 7 6 9 Same as benchmark 7 9 7 Unknown relationship Sum-Up Score 0% 18.4 18.8 14.4 Sum-Up Compared to benchmark: Symbol Value Better than benchmark b 1 Perform this check in a round robin fashion. Worse than benchmark w -1 Let the prevailing concept from one round be Same as benchmark s 0.2 the benchmark in the next! Unknown relationship u "0" 20
Concept Iteration Template Current Rank Concept ID. Concept Description 1 Best Rail/Track 2 A Drum Dumper 3 B Turning Concept Selection Table ID. Best A B C D E F Metrics % Rail/Track Drum DumperTurning 0 0 0 0 Speed of Process 18 1 1 Ease of Operation 11 0.2 -1 One man operation 11 0.2 -1 number of pinch points 10 1 -1 amount of waste 5 -1 -1 stability of instrument 5 1 -1 force required to operate 5 0.2 -1 breakage of catalyst 5 0.2 0.2 weight of intrument 4 -1 1 footprint size 4 1 1 electrical rating 4 0.2 0.2 cost of implentation 3 0.2 0.2 repairability 3 -1 0.2 reliability 3 0.2 1 special training to repair 3 0.2 0.2 Special Tools 3 0.2 0.2 special training to operate 2 0.2 0.2 stability of catalyst drum 1 1 -1 resistance to corrosion 1 Re-chk 0.2 0.2
Better than benchmark 5 4 Worse than benchmark 3 7 Same as benchmark 11 8 Unknown relationship Re-chk Score 0% 4.2 -1.4 21
Concepts Concept Descriptions Current System Hoist > Hand Truck > Bucket > Let Down by Hoist A Hoist > Hand Truck > Drum Dumper > Bird Feeder > Let Down by Hoist B Hoist > Modified Drum Dumper > Screw Conveyor > Funnel > Let Down by Hoist C Cable and Rail > Lid Removal > Funnel > Let Down by Reverse D Hoist > I-Beam > Drum Tipper > Bird Feeder > Let Down by Hoist E F
Concept Selection Table Metric Information Conceptual Solutions Benchmark A B C D E F Metrics % Target value Speed of Process 17 1 1 1 1 Ease of Operation 14 1 1 1
Force Required to Operate 10 1 1 1 1 Number of Pinch Points 9 0.2 0.2 0.2 0.2 One Man Operation 8 0.2 0.2 0.2 0.2 Cost of Implementation 7 -1 -1 -1 -1 Electrical Rating 5 -1 -1 0.2 0.2 Stability of instrument 4 1 1 1 1 Reliability 4 -1 -1 -1 -1 Weight of instrument 3 -1 -1 -1 -1 Footprint size 3 0 0 0 0 Repairability 3 -1 -1 -1 -1 Special Tools 2 -1 -1 -1 -1 Special Training to repair 2 -1 -1 -1 -1 Breakage of Catalyst 2 0.2 0.2 0.2 0.2 Stability of catalyst drum in instrument 1 0.2 0.2 1 0.2 Amount of Waste 1 0.2 0.2 0.2 0.2 Special Training to operate 1 0.2 0.2 0.2 0.2 Resistance to Corrosion by catalyst and ambient conditions 1 0.2 -1 0.2 0.2
Better than benchmark Worse than benchmark Same as benchmark Unknown relationship Sum-Up Score 0% -1.6 -3.8 0.4 -0.4 Sum-Up Compared to benchmark: Symbol Value Better than benchmark b 1 Perform this check in a round robin fashion. Worse than benchmark w -1 Let the prevailing concept from one round be Same as benchmark s 0.2 the benchmark in the next! Unknown relationship u "0" 22
Concept Iteration Template Current Rank Concept ID. Concept Description 1 Best Cable and Rail > Lid Removal > Funnel > Let Down by Reverse 2 A Hoist > Hand Truck > Drum Dumper > Bird Feeder > Let Down by Hoist 3 B Hoist > Modified Drum Dumper > Screw Conveyor > Funnel > Let Down by Hoist 4 C Hoist > I-Beam > Drum Tipper > Bird Feeder > Let Down by Hoist Concept Selection Table ID. A B C D E F G Metrics % Hoist > I-Beam > Drum0 Tipper > 0Bird Feeder0 > Let Down0 by Hoist Speed of Process 17 -1 -1 0.2 Ease of Operation 14 -1 -1 -1
Force Required to Operate 10 -1 0.2 -1 Number of Pinch Points 9 0.2 0.2 0.2 One Man Operation 8 0.2 0.2 0.2 Cost of Implementation 7 1 0.2 1 Electrical Rating 5 -1 -1 0.2 Stability of instrument 4 -1 0.2 0.2 Reliability 4 0.2 -1 0.2 Weight of instrument 3 1 0.2 0.2 Footprint size 3 0.2 0.2 0.2 Repairability 3 1 -1 -1 Special Tools 2 0.2 0.2 0.2 Special Training to repair 2 0.2 0.2 0.2 Breakage of Catalyst 2 0.2 0.2 0.2 Stability of catalyst drum in instrument 1 -1 -1 -1 Amount of Waste 1 0.2 0.2 0.2
Special Training to operate 1 Re-chk 0.2 0.2 0.2 Resistance to Corrosion by catalyst and ambient conditions 1 -1 -1 0.2
Better than benchmark Worse than benchmark Same as benchmark Unknown relationship Re-chk Score 0% -2.2 -4.6 -0.2 23
Appendix B: Failure Analysis for Rail, Structure and Cart Four-bar Linkage
This report will consider the likelihood of the buckling of the vertical supports under static and cyclical loading. The vertical supports are 2” square hollow steel tubes with a wall thickness of 0.12 inches. The analysis modeled each vertical member as an individual with fixed ends. The load that each member would experience is at most 500 pounds.
Results:
The vertical member of the rail will not buckle. Safety factor for static buckling: 79 Safety factor for cyclical buckling: 21 No risk of cyclical failure.
Matlab program: Program results:
% Failure analysis of the support structure Critical load = 3.9542e+004 lbs max_load= 500 % psi Critical stress = 8.4928e+004 psi % Dimensions and Characteristics Static safety factor = 79.0847 L=92 % in Cyclic safety factor = 21.4284 x= 2 % in wall= 0.12 % in E=29*10^6; % psi I= x^4/12-(x-wall)^4/12; % in^4 yield_stress= 36*10^3; % psi, compressive and tensile stress
% Static buckling
K=0.5 % For fixed ends A=x^2-(x-wall)^2; r=sqrt(I/A); P_cr= pi^2*E*I/(K*L)^2 stress_cr=pi^2*E/(K*L/r)^2 static_sf=P_cr/max_load
% Dynamic buckling
S1=0.5*yield_stress; % Endurance limit C_l=1; % Loading factor, bending A_95=0.05*x^2; % Equation for size factor d=sqrt(A_95/0.0766); C_d=0.869*d^(-.097); % Size factor C_s=0.8; % Surface factor, machined C_r=0.897; % 90% reliability % No temperature factor S_e=S1*C_l*C_d*C_s*C_r dyn_sf=S_e/max_load Rail System 24
L L 1 2 P= Load = 500 lb L1= 18 in L = 24 in F F 2 5 6 R = 24 in R h= 92 in F C3X6: 4 * O Web height = 3 in Web thickness = .356 in Web Leg length = 1.596 in thickness Leg thickness = .273 in
F y h 3 x Web height
Leg thickness Leg length F 2
F 1
Results:
The vertical member of the rail will not buckle. Safety factor for bending and torsion of the rail system, static: 3.8 Safety factor for the cyclic bending and torsion of the rail system: 1.14 Maximum bending deflection: 0.04 inches Maximum twisting deflection: 0.2 degrees No risk of cyclical failure. 25
Analysis
Variables:
P = load σ = stress ρ = radius of curvature s.f. = safety factor E = modulus of elasticity h = height ρinner = radius of inner rail I = moment of inertia A = cross-sectional area ρn = neutral axis r = radius of gyration δ = deflection θ = angular deflection
Bucking of the Vertical Member:
2 EI 2 E P P cr cr h 2 L / r2 A * using the smallest I and related r
Transverse Bending of the Horizontal Member along L1 (middle) and L2 (end):
L P 1 * weblength PL * weblength 2 2 maxbending,end maxbending,middle 2I x 2I x
PL3 3 1 PL2 max,middle max,end 48EI x 3EI x
Transverse Bending of Curved Member:
I c x c A n
M max P sin( / 4) ( cos( / 4)) P cos( / 4) ( sin( / 4)) * Maximum moment at center of curve where the force is applied 45º from the horizontal
M max inner weblength n M max inner n top bottom Ac inner weblength Ac inner
Axial Force and Bending of the Curved Member:
P M max n axial A Ac n 26
Torsion of Horizontal Member:
2legthickness (leglength webthickness)3 weblength webthickness3 It 1.12 3 3 I S t t leglength
P (leglength webthickness) 180 PL2 (leglength webthickness) max,torsion St GI t
Distortion of Cross-Sectional Area:
P(leglength webthickness)3 M max P(leglength webthickness) max 2EI x
Static Loading Failure - von Mises Effective Stress: * At the end of the cantilevered rail where the stresses are greatest
x max bending,end y P max,torsion
2 2 2 yield combined x x y y 3 s. f . combined
Dynamic/ Cyclical Failure:
This system would be analyzed for low-cycle fatigue, with fewer than 60 cycles each year. For steel, the endurance limit under which the material can be cycled infinitely without failure, is about one half the ultimate strength when considering a test specimen. When correction factors accounting for the type of loading, the size, the surface finish, temperature, and reliability were calculated and factored in, the endurance limit for the steel, under which the system could theoretically cycle an infinite number of times, was 1.14 times greater than the stress to which the system would be subjected.
Sources:
Hibbeler, R. C. Mechanics of Materials, 6th Ed. Upper Saddle River, NJ: Pearson Education, Inc, 2005. pp. 185-372, 667-677.
Norton, Robert L. Machine Design: An Integrated Approach, 3rd Ed. Upper Saddle River, NJ: Pearson Education, Inc, 2006. pp. 137-144, 299-338.
Mikhelson, Ilya. Structural Engineering Formulas. New York: McGraw-Hill, 2004. 228 pp. 27
MATLAB Programs and Results
Static and Dynamic Rail Failure Program
% Static and Dynamic Failure Analysis for Rail System
% Rail characteristics % C3X6 American Standard Channels/C Shapes % Structural Steel % Assumed load = 500 lb P=500; % lb E=29*10^6; % psi G=11*10^6; % psi yield_stress= 36*10^3; % psi, compressive and tensile stress leg_lth=1.596; % in leg_th=0.273; % in web_lth=3; % in web_th= 0.356; % in leg_2=leg_lth-web_th; % in I_x=2.07; % in^4 S_x=1.38; % in^3 r_x=1.08; % in I_y=0.305; % in^4 S_y=0.268; % in^3 r_y=0.410; % in A=1.76; % in^2 L_mid=18; % in L_end=24; % in
% Buckling of vertical member h= 92; % in P_cr=pi^2*E*I_y/(0.5*h)^2 % lb stress_cr=pi^2*E/(0.5*h/r_y)^2 % psi stress=P/A % psi buckling_sf=stress_cr/stress
% Transverse bending of horizontal bend_stress_max_mid=P*L_mid/2*web_lth/2/I_x % psi bend_deflect_max_mid=-P*L_mid^3/(48*E*I_x) % in bend_stress_max_end=P*L_end*web_lth/2/I_x % psi bend_deflect_max_end=-P*L_end^3/(3*E*I_x) % in bending_sf=yield_stress/bend_stress_max_end
% Transverse bending of curved member rad_curvature= 24; % in rad_rail_1=rad_curvature-web_lth/2; c=I_x/(A*rad_curvature); rad_neutral1=rad_curvature-c; t=pi/4; M_max=P*sin(t)*(rad_curvature-rad_curvature*cos(t))+P*cos(t)*(rad_curvature-rad_curvature*sin(t)) % lb-in bend_stress_curve_top=-M_max/(A*c)*(rad_rail_1+web_lth-rad_neutral1)/(rad_rail_1+web_lth) % psi bend_stress_curve_bottom=-M_max/(A*c)*(rad_rail_1-rad_neutral1)/rad_rail_1 % psi curve_sf=yield_stress/bend_stress_curve_bottom 28
% Axial force and bending of the curved member axial_stress=P/A+M_max/(A*c)*(rad_curvature-rad_neutral1)/rad_neutral1 % psi
% Torsion of horizontal member I_t=1.12*(2*leg_th*leg_2^3/3+web_lth*web_th^3/3); % in^4 S_t=I_t/leg_lth; % in^3 max_stress_tors=P*leg_2/S_t % psi ang_deflection=180/pi*P*leg_2*L_end/(G*I_t) % degrees
% Distortion of Cross-Sectional Area M_max_2=P*(leg_lth-web_th) deflect_max=-P*(leg_lth-web_th)^3/(2*E*I_x)
% Static Loading failure - von Mises effective stress % At curved member (top) sigma_x=bend_stress_curve_top-axial_stress; sigma_y=P; tau=max_stress_tors; comb_stress=sqrt(sigma_x^2-sigma_x*sigma_y+sigma_y^2+3*tau^2) comb_stress_sf=yield_stress/comb_stress
% At end of the rail (cantilever) sigma_x_2=bend_stress_max_end; sigma_y_2=P; tau_2=max_stress_tors; comb_stress2=sqrt(sigma_x_2^2-sigma_x_2*sigma_y_2+sigma_y_2^2+3*tau_2^2) comb_stress_sf2=yield_stress/comb_stress2
% Dynamic failure analysis S1=0.5*yield_stress; % Endurance limit C_l=1; % Loading factor, bending A_95=0.05*web_lth*leg_lth; % Equation for size factor, C-channel d=sqrt(A_95/0.0766); C_d=0.869*d^(-.097); % Size factor, C-channel C_s=0.8; % Surface factor, machined C_r=0.897; % 90% reliability % No temperature factor S_e=S1*C_l*C_d*C_s*C_r dyn_sf=S_e/comb_stress2
Test Results bend_stress_curve_bottom = 3.7165e+003 psi P_cr = 4.1256e+004 psi curve_sf = 9.6866 stress_cr = 2.2738e+004 psi axial_stress = 402.0060 psi stress = 284.0909 psi max_stress_tors = 2.2531e+003 psi buckling_sf = 80.0373 ang_deflection = 0.1765 degrees bend_stress_max_mid = 3.2609e+003 psi M_max_2 = 620.0000 lb-in bend_deflect_max_mid = -0.0010 in deflect_max = -7.9403e-006 in bend_stress_max_end = 8.6957e+003 psi comb_stress = 5.7151e+003 psi bend_deflect_max_end = -0.0384 in comb_stress_sf = 6.2991 bending_sf = 4.1400 comb_stress2 = 9.3138e+003 psi M_max = 4.9706e+003 lb-in comb_stress_sf2 = 3.8652 psi bend_stress_curve_top = -3.5007e+003 psi S_e = 1.0621e+004 psi dyn_sf = 1.1404 29
Four-Bar Linkage Failure Program % Analysis of the Four-Bar Linkage % US units clear all
% Assumtions
% Material - A36 E1=29*10^6; % psi SYield=36*10^3; % psi Sut=58; % kpsi (needs to be in kpsi in correction eqn) specW=0.284; % lb/in^3
% Cross section - 1.5" thick by 2" solid p=1.5; % in q=2; % in % Area Properties Iy=(1/12)*p*(q^3); in^4 larea=p*q;
% Link Lengths L1=34; % in L2=24; L3=((L2^2)+(23^2))^(1/2); L4=((23^2)+(34^2))^(1/2);
Lp=L2/2; % Moment Arm for piston (wrt cg) Gpy=3.8296*12; % ground psn for pistons taken from Cad Gpx=1.1642*12; % ground psn for pistons taken from Cad
% Mass Properties Wbarrel=450+50; % lb; the extra 50 is for the nest weight
% Loop for input link angle for n=1:46, theta2(n)=(n-1)*pi/180;
%%%%%%%%%%% % Position Analysis % %%%%%%%%%%%
% First find theta3 and theta4 a=L2; b=L3; c=L4; d=L1;
K1=d/a; K2=d/c; K3=((a^2)-(b^2)+(c^2)+(d^2))/(2*a*c); A=cos(theta2(n))-K1-K2*cos(theta2(n))+K3; B=-2*sin(theta2(n)); C=K1-(K2+1)*cos(theta2(n))+K3; 30
K4=d/b; K5=((c^2)-(d^2)-(a^2)-(b^2))/(2*a*b); D=cos(theta2(n))-K1+K4*cos(theta2(n))+K5; E=B; F=K1+(K4-1)*cos(theta2(n))+K5;
theta4(n)=2*atan((-B-(sqrt((B^2)-4*A*C)))/(2*A)); theta3(n)=2*atan((-E-(sqrt((E^2)-4*D*F)))/(2*D));
% Use the position to determine the barrel tilt thetab=(pi-(atan(23/34)+theta4(n)));
%%%%%%%%%% % Force Analysis % %%%%%%%%%% % Start with the linkage in the 'collapsed' configuration
% Specify link center of gravities Rg2x=(L2/2)*cos(theta2(n)); Rg2y=(L2/2)*sin(theta2(n)); Rg3x=(L3/2)*cos(theta3(n)); Rg3y=(L3/2)*sin(theta3(n)); Rg4x=(L4/2)*cos(theta4(n)); Rg4y=(L4/2)*sin(theta4(n));
% Setup some geometry; Design of Machinery Chapter 11 style R12x=-Rg2x; R12y=-Rg2x; R23x=-Rg3x; R23y=-Rg3y; R14x=-Rg4x; R14y=-Rg4y;
R32x=Rg2x; R32y=Rg2y; R43x=Rg3x; R43y=Rg3y; R34x=Rg4x; R34y=Rg4y;
% Parameters relating to the applied force Rpx=(Lp+L2/2)*cos(theta2(n)); Rpy=(Lp+L2/2)*sin(theta2(n)); xxx(n)=L2*cos(theta2(n))-Gpx; yyy(n)=Gpy-L2*sin(theta2(n)); eta(n)=atan((L2*cos(theta2(n))-Gpx)/(Gpy-L2*sin(theta2(n)))); thetap(n)=eta(n)+pi/2;
% Setup Force Matrix % B=[ F12x F12y F32x F32y F43x F43y F14x F14y Fp ]'
A=[ 1 0 1 0 0 0 0 0 cos(thetap(n)); % carfeul w/ the - 0 1 0 1 0 0 0 0 sin(thetap(n)); -R12y R12x -R32y R32x 0 0 0 0 (Rpx*sin(thetap(n))-Rpy*cos(thetap(n))); % carfeul w/ the - 31
0 0 -1 0 1 0 0 0 0; 0 0 0 -1 0 1 0 0 0; 0 0 R23y -R23x -R43y R43x 0 0 0; 0 0 0 0 -1 0 1 0 0; 0 0 0 0 0 -1 0 1 0; 0 0 0 0 R34y -R34x -R14y R14x 0;];
C=[ 0; 0; 0; 0; 0; 0; 0; Wbarrel 0;];
% solve for B B=A\C; % LU decomp doesn't produce anything different then direct solve
% Store All of these Valuables F12x(n)=B(1); F12y(n)=B(2); F32x(n)=B(3); F32y(n)=B(4); F43x(n)=B(5); F43y(n)=B(6); F14x(n)=B(7); F14y(n)=B(8);
Fp(n)=1.2*B(9); % 20% extra factored in for friction and inertia
check(n)=rcond(A); % accuracy gauge
%%%%%%%%%%%%%%%%%%%%%%%% % Resovle into shear and normal components % %%%%%%%%%%%%%%%%%%%%%%%%
% Link2 F12n2(n)=F12x(n)*cos(theta2(n))+F12y(n)*sin(theta2(n)); F12s2(n)=F12y(n)*cos(theta2(n))-F12x(n)*sin(theta2(n)); % Again - is intentional F32n2(n)=F32x(n)*cos(theta2(n))+F32y(n)*sin(theta2(n)); F32s2(n)=F32y(n)*cos(theta2(n))-F32x(n)*sin(theta2(n));
Fpx(n)=Fp(n)*cos(thetap(n)); Fpy(n)=Fp(n)*sin(thetap(n)); Fpn2(n)=Fpx(n)*cos(theta2(n))+Fpy(n)*sin(theta2(n)); Fps2(n)=Fpy(n)*cos(theta2(n))-Fpx(n)*sin(theta2(n));
F12mag(n)=((F12n2(n))^2+(F12s2(n))^2)^(1/2); F32mag(n)=((F12n2(n))^2+(F12s2(n))^2)^(1/2);
% Link3 32
F43n3(n)=F43x(n)*cos(theta3(n))+F43y(n)*sin(theta3(n)); F43s3(n)=F43y(n)*cos(theta3(n))-F43x(n)*sin(theta3(n)); F32n3(n)=-F32x(n)*cos(theta3(n))-F32y(n)*sin(theta3(n)); F32s3(n)=-F32y(n)*cos(theta3(n))+F32x(n)*sin(theta3(n));
F43mag(n)=((F43n3(n))^2+(F43s3(n))^2)^(1/2);
% Link4 F43n4(n)=-F43x(n)*cos(theta4(n))-F43y(n)*sin(theta4(n)); F43s4(n)=-F43y(n)*cos(theta4(n))+F43x(n)*sin(theta4(n)); F14n4(n)=F14x(n)*cos(theta4(n))+F14y(n)*sin(theta4(n)); F14s4(n)=F14y(n)*cos(theta4(n))-F14x(n)*sin(theta4(n));
F14mag(n)=((F14n4(n))^2+(F14s4(n))^2)^(1/2); end
%%%%%%%%%% % Stress Analysis % %%%%%%%%%%
Sep=0.5*Sut; % kpsi A95=0.05*(larea); % Machine Design pg 327 deq=(A95/0.0766)^(1/2); Cload=0.7; %Some axial load present Csize=0.869*(deq^-0.097); % changes if deq > 10 in Csurf=2.7*(Sut^-0.265); Ctemp=1; Crel=0.702; % 99.99% reliablilty Se=Cload*Csize*Csurf*Ctemp*Crel*Sep; % Corrected endurance limit (kpsi)
% Link2 - Assume worst case (cantileaver) Vmax2=max(Fps2); % Max shear is max of two reactions (lb) Mmax2=max(Fps2)*((L2/2)+Lp); % (lb-in^2) taumax2=(1.5*(Vmax2/larea)); % Changes if cross xection type does (psi) Sbend2=Mmax2*(0.5*q)/Iy; % Make sure to use area inertia (psi) Snormal2=max(max(abs(F12n2)),max(abs(F32n2)))+max(Fpn2); Kf=1.1162; % Calculated seperate (pg340 MD) Snormalmax2=Kf*(Sbend2+Snormal2); sig12=Snormalmax2/2+taumax2; sig32=Snormalmax2/2-taumax2; sigp2=((sig12^2)-(sig12*sig32)+(sig32^2))^(1/2);
% I'll assume that the beam isn't loaded at the extended position sigpa2=(sigp2/2)/(10^3); % alternating von mises sigpm2=(sigp2/2)/(10^3); % mean von mises
Nf2=Se*Sut/(sigpa2*Sut+sigpm2*Se); % all from Machine Design
% Link3 - Only normal stress Snormalmax3=max(max(abs(F12n2)),max(abs(F32n2))); % Since this member is only loaded axially, the max stress is the von mises stress sigpa3=(Snormalmax3/2)/(10^3); 33 sigpm3=(Snormalmax3/2)/(10^3);
Nf3=Se*Sut/(sigpa3*Sut+sigpm3*Se);
% Link4 - Not exactly sure how to model
% Ground Link - Assume square solid 2"x2" Ig=1.333; % in^4 LL=16; % in Mmaxg=(max(Fp))*LL; Snormmax=Mmaxg*1/Ig; % psi sigpag=(Snormmax/2)/(10^3); sigpmg=(Snormmax/2)/(10^3);
Nfg=Se*Sut/(sigpag*Sut+sigpmg*Se);
% Buckling Load; checked - it's well within limit Pcr2=(pi^2)*E1*Iy/(L2^2); Pcr3=(pi^2)*E1*Iy/(L3^2);
% Help for bearing selection; finds max resultant force at joints maxloads=[ max(F12mag); max(F32mag); max(F43mag); max(F14mag); ]; maxload=max(maxloads);
% Help for Piston Posn tog1=acos(((a^2)+(d^2)-(b^2)-(c^2))/(2*a*d)+(b*c/(a*d))); tog2=acos(((a^2)+(d^2)-(b^2)-(c^2))/(2*a*d)-(b*c/(a*d)));
Test Results
Se = 11.0345 Snormalmax2 = 2.6841e+004 Nf2 = 1.3789 Nf3 = 20.9046 Nfg = 1.5646 Pcr2 = 4.9691e+005 Pcr3 = 2.5902e+005 maxload = 1.2285e+003 tog1 = 0 + 0.2183i tog2 = 3.1416 - 1.4849i 34 35 Appendix C: Design Package
Page 1 – Overall Sketch Page 2 – Track Assembly Page 3 – Track References Page 4 – Support Dimensions Page 5 – Track Dimensions Page 6 – Cart Assembly Page 7,8 – Cart References Page 9 – Cart Frame Dimensions Page 10 – Link Dimensions Page 11 – Nest Dimensions 36 37 38 39 40 41 42 43 44 45 46 47 Appendix D: Bill of Materials/Cost Analysis Item Price (ea.) Price Supplier Model/Part # Description
Pneumatic Cylinder $141 $564 McMaster-Carr 6471K29 2.5" Dia, 18.5" stroke Rod Clevis w/ Pin $7 $28 McMaster-Carr 6471K64 For Rod end of Actuators Clevis/Pivot Bracket $24 $96 McMaster-Carr 6471K77 For Base end of Actuators Steel for Links $182 $363 McMaster-Carr 6554K736 72" long, 1.5" Thick x 2" Wide Yoke Wheels $66 $263 McMaster-Carr 1480T54 2.5" Dia, 1.75" Wide Steel for Frame $135 $942 McMaster-Carr 9143K256 2" Wide x 2" Thick, 72" long Pins for Links $10 $10 McMaster-Carr 98306A399 10 pack, 0.5" dia, 3.5" long Bearings for Links $8 $130 McMaster-Carr 5905K63 0.5" shaft, 11/16" OD Cotter Pin $6 $6 McMaster-Carr 98355A200 10 pack, Stainless Steel
Winch $5,200 $5,200 Jeamer Winches Custom 1100lb lift, Bi-Directional Pulley $16 $16 Sheaves, Inc 104044 3" OD, 1/2" Bore Pulley $100 $100 Sheaves, Inc Custom 5" OD, 1/2" Square Bore, Idler Roller $79 $79 Roach Conveyors 3530S-31 31" Heavy Duty Roller Roller Fairlead $45 $45 Warn 69602 8.5" Length, 45mm Dia. Rollers Springs $21 $42 McMaster-Carr 96485K293 Steel 3-21/32"OD 12"Length Pneumatic air supply $1,000 $1,000 Air Products and switches
Track $1,500 $1,500 C3x6 Steel U-Channel Supports $41 $287
Cone $1,200 $1,200 Morse Mfg. Co. 5 VF 60 23 Clamp Collar $200 $200 Morse Mfg. Co. (7-23) Size #23
Safety Fence $500 $500 McMaster-Carr Labor $2,000 $2,000
Total $14,569 48 Appendix E: Hazards Operations Review
Project Hazard Review
Date: 10/31/06 Project Title: Catalyst Charge System Team Members: Team 2, Maureen Oliveria, Joe Trope, and Paul Young
Deviation Cause Consequence Recommendation Need a device to secure drum for Drum falling on operator Operator error Injury when its lifted and a mechanical stop for end of track
Safety gate, personal guards, Operator access to Less personal safety Injury switches at a safe distance from equipment when running equipment, 2 finger safety switches
Develop a procedure for proper No procedure New equipment Misuse operation
Lack of maintenance No PM's Reliability develop adequate PMs for equipment
Design prevents against catalyst Containment Spill during tipping catalyst spilling spillage into lifting system System grounded to reactor and Static Electricity Moving parts Fires building, spark resistant parts Feeding catalyst too fast Properly size and regulate air High flow Speed of actuator causing breakage pressure Catalyst does not get Low/No flow Spout too small Investigate sizing funnel correctly dumped Drum spout not properly Calculate and test where to place Misdirected flow Spilling catalyst aligned with opening spout in cone Not enough supply Cant lift drum, cant Investigate hoist and piston air Low air pressure pressure activate drum tipping requirement Drum fall causing injury Verify if break activates upon loss of No pressure Loss of air pressure and catalyst spillage air for winch and pistons Paint coatings Catalyst contamination Reactor efficiency quality No paint coating on cone for drum contaminates catalyst 49 Appendix F: Safe Work Practice SAFE WORK PRACTICE O-09
REACTOR CATALYST CHANGE OUT Page1 of 4 Revised: April 6, 2018
REQUIRED PRTOTECTIVE EQUIPMENT: Nomex work clothes, safety shoes, safety glasses, hard hat, goggles when needed, leather work gloves, air pack in area, safety harness in area, throw-away Tyvek suits, and supplied fresh air equipment.
RECOMMENDED PROTECTIVE EQUIPMENT: respirator with appropriate organic vapor and dust filters.
JOB STEPS IN SEQUENCE POTENTIAL HAZARDS RECOMMENDED SAFE PRACTICE
1. Read and complete sections See Reactor Operating See Reactor Operating Reactor. 4.1-4.4 “Normal Shutdown” Procedure. from Reactor Operating Barricade work area with red tape. Procedure.
Maintenance will perform the following:
2. Remove insulation blankets Dust inhalation when removing Wear respirators with appropriate dust on reactor manway. Insulation blankets. filters when removing insulation blankets.
3. Remove nuts and bolts Pinch points. Wear leather work gloves. from reactor top manway with impact gun.
4. Install hoist to elevate Falls. Tie off ladder, use three point contact reactor top manway. on ladder.
5. Open top manway. Pinch points on hoist. Wear leather work gloves.
Possible loss of consciousness Do not put head closer than 24” from due to N2 atmosphere in reactor. open manway.
Manway falling. Inspect and use appropriate rigging equipment and slings.
If catalyst sampling is to be done:
6. Obtain instructions on how to None. None. sample catalyst before unloading of the catalyst begins.
7. Sample the used catalyst from Dust inhalation. All personnel working in the area are the top, middle, and bottom of required to use respirators with reactor. appropriate dust filters in addition to normal required protective equipment.
Removing the used catalyst: 50 SAFE WORK PRACTICE O-09
REACTOR CATALYST CHANGE OUT Page2 of 4 Revised: April 6, 2018
JOB STEPS IN SEQUENCE POTENTIAL HAZARDS RECOMMENDED SAFE PRACTICE
8. After maintenance has opened Dust inhalation. All personnel working in the area are the reactor, the Maintenance required to use respirators with Coordinator will contact appropriate dust filters in addition to appropriate contract personnel normal required protective equipment. to remove used catalyst by vacuum suction.
Catalyst is transferred to 55- Possible hot spots in the catalyst. Have water ready in case it is needed gallon drums. Drums are filled for quench any hot spots that may in place on a pallet and are develop. removed when full to a storage area.
If inspection and repairs needs to be done:
9. Process Coordinator will Dust Inhalation. All personnel working in the area are inspect the distribution plates required to use respirators with and determine the necessary appropriate dust filters in addition to repairs that need to be done. normal required protective equipment.
10. Maintenance will take the Confined space. Vessel entry permit is required. (See necessary UT reading and Confined Space Entry Procedure in perform the necessary Safety manual Section 37 repairs. \\pbadnt\safety\Safety Manual\SECT37.DOC).
For each person working inside the reactor, a complete unit of breathing mask hose and breathing air is required. (See Safety Manual Section 53 \\pbadnt\safety\Safety Manual\SECT37.DOC). A safety harness is required before entering the reactor.
Dust inhalation. Before entering the reactor, do an explosive meter test of the vessel and have the Process Coordinator perform a safety test.
Hoisting drums of fresh catalyst to platform:
11. Use rig to lift one Drums falling off rig. Barricade area around rig with red tape. drum from the ground to 2-floor Inspect and use good rigging equipment. platform. NOTE: Follow steps Roll drum onto rig and secure with chain. through charging drum to reactor No one should be under rig during before lifting the next drum. elevation of drums.
Electrocution. Use chain or rope to hoist drums over to the platform. Do not use the power 51 cable to pull the drums over to platform.
SAFE WORK PRACTICE O-09
REACTOR CATALYST CHANGE OUT Page 3 of 4 Revised: April 6, 2018
JOBS STEPS IN SEQUENCE POTENTIAL HAZARDS RECOMMENDED SAFE PRACTICE
Pinch points. Wear leather work gloves.
Pinch points. Wear leather work gloves.
12. Relocate drum to the south Back injuries. Follow SWP O-32 W for manually side of the reactor using a drum moving drums of material on and off trolley. trolley.
Charging fresh catalyst into reactor:
13. Unload the drum from trolley Pinch points. and place it partly into the cart with lid hinge facing outwards. Back injuries.
14. Remove drum lid. Take Pinch points. samples if required. Check with the process coordinator or process engineer if a sample is required. Install drum cone. Slide drum completely into cart.
15. Hook strap around barrel and Pinch points. tighten the ratchet
16. Use winch controls to raise Pinch points and translate cart to manhole.
17. Slide in the two safety pins Pinch points. that hold the cart in the top of the track
18. Rotate drum upwards with Spillage of catalyst. pneumatic controls. Wait for catalyst to finish pouring out. Rotate drum downward with Pinch points. same controls.
Dust inhalation.
19. Remove safety pins from the Pinch points. cart and supports. 52
Wear leather work gloves. Wear leather work gloves.
Follow SWP O-32 W for manually moving drums of material on and off trolley If cart is pinned in place, spillage should not occur. Wear leather work gloves. Keep all personnel away from cart while it is moving.
All personnel working in the area are required to use respirators with appropriate dust filters in addition to Wear leather work gloves. normal required protective equipment.
Wear leather work gloves. Keep all personnel away from cart while it is moving. 53 SAFE WORK PRACTICE O-09 REACTOR CATALYST CHANGE OUT Page 4 of 4 Revised: April 6, 2018
JOBS STEPS IN SEQUENCE POTENTIAL HAZARDS RECOMMENDED SAFE PRACTICE
20. Use winch controls to Pinch points. Keep all personnel away from cart translate and lower cart. while it is moving.
21. Remove empty drum from Pinch points. Wear leather work gloves. cart.
22. Repeat steps 11 through 19 None. None. until all drums of catalyst have been charged to the reactor.
23. After charging all the None. None. catalyst, level the catalyst and measure the outage (distance from top of reactor manway to top of catalyst bed). Fill out drum charge sheet and forward to the Process Coordinator. Contact maintenance to button up the reactor.
Maintenance will perform the following:
22. Install hoist to lower reactor Falls. Tie off ladder, use three point top manway. contact on ladder.
23. Tighten nuts and bolts on Pinch points on hoist. Wear leather work gloves. reactor top manway with impact gun.
24. Install insulation blankets on Dust inhalation when installing Wear respirators with reactor manway. insulation blankets. appropriate dust filters when installing insulation blankets.
25. After the system is fully None. None. heated up to temperature, write a work request for Maintenance to retighten reactor bolts.
26. Retighten nuts and bolts on Pinch points. Wear leather work gloves. reactor top manway with impact gun.
Note: Wearing a supplied air mask and safety harness is required before entering the reactor. All APCI or contractor supplied breathing air cylinders are inspected, approved and tagged in accordance with Safety Manual Section 53 “Breathing Air Cylinders Testing and Oxygen Checks”.
Reference: Safety Manual Section 37 “Confined Space Entry Procedure” Safety Manual Section 53 “Breathing Air Cylinders Testing and Oxygen Checks” 54 Appendix G: Gantt Charts
Gantt Chart for October 3-December 12, 2006 55