Unloaders. Selecting the right system. Vincent van der Wijk

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1 Unloaders Selecting the right system Vincent van der Wijk Title Author 2005

2 Agenda Selecting the right ship unloading system Practical implications Functional principles and technical configuration Energy consumption Active working range Rest unloading of product out of the hatch Operational handling & Maintenance costs Product protection 2 Bühler Unloaders Vincent van der Wijk

3 Selecting the right ship unloading system. For efficient unloading of grain and other free flowing bulk goods, several continuous ship unloading systems (CSU) such as a vertical chain, pneumatic, and belt conveyer are employed worldwide. Each of these systems is founded on sophisticated, powerful technology and can be the perfect instrument for a specific area of application. An often-used rule of thumb is that pneumatic unloaders are an option with lower unloading capacities up to 600 t/h, while mechanical unloaders show off their strengths at higher capacities. 3 Bühler Unloaders Vincent van der Wijk

4 All continuous ship unloaders serve the same basic purpose: to unload grain or other bulk goods as efficiently as possible. But each system possesses specific advantages that make it the preferable choice for certain areas of application. To make an informed and wellfounded decision on which unloader is the best solution for your terminal, basic issues have to be considered and evaluated, such as costs, energy consumption, availability, safety, etc. choice and level of investment for new unloaders. The Technical University of Munich has compared the three unloading systems shown below. Safety and regulations for the unloader applies not only to the operating personnel, but also to the equipment itself. For the owner of a port terminal, it is inadvisable to try to save on safety factors, and inadequate performance with regard to these criteria can have a serious impact on running the business. With unloading vessels of more than DWT, the average capacity for the total unloading process, in combination with the reliability of the unloader during operation, are the key functions. Because the unloader is the backbone of a terminal and its overall operation, fluctuations in capacity or breakdowns have a direct, significant impact and create high overall costs. Moreover, several regulatory specifications relating to personnel and environmental safety are influencing the Chain Belt Pneumatic Availability Material breakage Ease of operation Safety of unloader Dust emission Noise emission Bühler

5 Selecting the right unloader 5 Bühler

6 Practical implications. To show the bottom line implications of the study made by the TU Munich, Buhler has prepared a comparison between the three continuous unloading systems based on a customer project developed in Central Europe which projects to unload grain. The project details are in the customer profile. Key investment criteria are the operational expenditures (OPEX) in combination with the capital expenditure (CAPEX). For an optimal customer solution, these criteria should be in balance. As shown in the figure, the Buhler system featuring a highly efficient vertical chain conveyer has the lowest OPEX value of the available CSUs. With lower overall efficiency and relatively high replacement costs, the belt conveyer and pneumatic systems have a higher OPEX and are therefore less favourable unloading options in this case. Customer profile Yearly Unloading volume t Energy costs 0.15 kwh Daily operating hours 22 Daily tie-up costs 25,000 Nominal capacity 600 t/h Demanded availability 90 % Daily personnel costs 247.5* * 5 p/h= Ø 2.25 m.p 6 Bühler

7 System comparison Chain Belt Pneumatic Average efficiency 75 % 65 % 65 % Annual unloading days Annual personnel costs Energy (kwh/t) 0,4 0,3 0,8 1,0 Annual energy costs Annual tie-up costs Annual wear & tear costs Annual operating costs Unloading costs per ton 2,97 3,47 3,56 Profit lost Bühler

8 Functional principles and technical configuration. Mechanical: Buhler's Portalink mechanical ship unloading system transports bulk material to the pier at low speed using two independent high-performance chain conveyors, one in the vertical conveying arm, the other in the boom. The Portalink has a standardized design based on years of experience and is optimally configured. The advantages of this design principle with few wearing parts and low conveying velocity include high dependability, low energy costs and reduced maintenance requirements. Low wear also ensures a constant conveying capacity with no losses in performance over the entire life cycle. Thanks to the minimal maintenance requirements, the amount of downtime of the entire installation decreases while system availability increases. 8 Bühler

9 Functional principles and technical configuration. Pneumatic: Pneumatic ship unloading systems include several additional components such as telescopable spouts, airlocks, filter systems and the suction nozzle. These parts require more maintenance and thus also lead to higher maintenance costs. The high conveying velocity of the bulk material also contributes significantly to the high level of wear unexpected failures of the installation are more probable with this system. Additionally, many of the parts must be designed to be particularly resistant to wear in order to withstand great forces. The frequency at which parts must be replaced is naturally greater, which increases the amount of downtime of the installation and reduces the availability of the system. 9 Bühler

Functional principles and technical configuration. The higher amount of wear also automatically causes a loss in capacity that reduces the overall efficiency of the unloader.

10 Functional principles and technical configuration. The higher amount of wear also automatically causes a loss in capacity that reduces the overall efficiency of the unloader. The berthing times of ships can also increase due to sudden stoppages in operation, leading to higher berthing fees. These disadvantages are less critical at lower conveying capacities and low annual throughput, since wearing parts do not need to be replaced as often and maintenance requirements are lower as a result. 10 Bühler

Overall efficiency While the Portalink unloading system continues to unload at constant full capacity as the level of bulk material sinks, the throughput of the pneumatic unloading system decreases

11 Overall efficiency While the Portalink unloading system continues to unload at constant full capacity as the level of bulk material sinks, the throughput of the pneumatic unloading system decreases by at least 10 % with a decreasing bulk material level and the suction pipes fully extended. The overall efficiency of the mechanical Portalink system is 87 %, whereas with the pneumatic system, efficiency is only 66 %. The result is astonishing! mechanical unloader, where a pneumatic unloader completes the process in a total of 131 hours. This represents roughly a 25 % increase in time for unloading a single ship! There are various reasons for the time savings offered by the mechanical unloader, all influencing the efficiency, such as the use of heavy bucket loaders to unload the material residues and the difference in throughput. For a customer with an unloading capacity of 600 t/h and mainly having Panamax size vessels the unloading time for the Panamax vessel comes to only 99 hours using the 11 Bühler

12 Active working range. Together with ease of operation, the working range and flexibility of the unloader is important. With a larger effective working range, the unloader can unload a broader area without moving, and thus increase the overall efficiency of the operation. Two persistent myths exist regarding unloading systems. The first myth is that pneumatic unloaders have a greater reach in the hatch than mechanical systems. The second myth is that with pneumatic unloading, the material left in the hatch after the main unloading phase is removed more efficiently and without the deployment of bulldozers. 12 Bühler

Mechanical: Mechanical unloading systems like the Buhler Portalink use the so-called "kick-in/kick-out system" to move the unloader arm through the hatch to unload with optimal coverage.

13 Mechanical: Mechanical unloading systems like the Buhler Portalink use the so-called "kick-in/kick-out system" to move the unloader arm through the hatch to unload with optimal coverage. In this process, the conveying arm moves through the bulk material in a curve. In this manner, it reaches the bulk material below the rim of the cargo hold without requiring repositioning of the ship (with stationary systems) or the unloader (with mobile systems). This flexibility significantly speeds up the unloading process and minimizes the need for bulldozers for removal of bulk material residues. Pneumatic: Pneumatic solutions are often compared with the vacuum cleaners used at home. In theory, this sounds logical, since both systems have a flexible hose and can move around easily but nothing is farther from the truth. In practice, bulldozers and bucket loaders are used to effectively remove all the bulk material residues from the cargo hold. Pneumatic unloaders can only adjust the position of the conveying arm vertically or horizontally. The bulk material below the rim of the cargo hold cannot be reached, requiring bulldozers to be used earlier and leading to longer unloading times. 13 Bühler

14 Rest unloading of product out of the hatch. Mechanical: Many modern unloading systems with mechanical technology are equipped with a winch integrated in the boom for moving large bulldozers into the cargo hold for highly efficient rest unloading. Depending on the capacity of the unloading system, they can offer a high load-bearing capacity up to 15 tons. In this case, the use of a single heavy bucket loader is sufficient to remove all cargo residues. The last remaining product in the hatch can conveniently be placed in the bulldozer's bucket and simultaneously lifted onto the pier. 14 Bühler

Rest unloading of product out of the hatch. Pneumatic: Pneumatic unloading systems have a lighter construction and are equipped with winches with a limited maximum load-bearing capacity of 3.5 tons.

15 Rest unloading of product out of the hatch. Pneumatic: Pneumatic unloading systems have a lighter construction and are equipped with winches with a limited maximum load-bearing capacity of 3.5 tons. If winches capable of bearing heavier loads are preferred, larger steel constructions are required, leading to increased costs compared to standard systems. Often, several smaller bulldozers or bucket loaders are moved into the hold to remove the remaining bulk material. Increased unloading time and berthing time of the ships results in an increase in costs. The basic advantage pneumatic systems offer, i.e. being able to remove literally every grain from the hold, is countered by their (physically determined) low residue unloading capacity. 15 Bühler

16 Operational handling. Mechanical: With the mechanical Buhler Portalink unloading system, operating staff only occasionally has to intervene in operation. The conveying arm automatically sinks into the bulk material and discharges large amounts of cargo at a constant throughput level before repositioning becomes necessary. The static construction of mechanical unloading systems does however have a disadvantage in that the water level can vary significantly during unloading. In this case, additional repositioning is required to adjust the unloader to the water level difference. 16 Bühler

17 Operational handling. Pneumatic: Without the benefit of the automatic "sink-in" function, operators of pneumatic unloading systems have to manually adjust the position of the conveying arm depending on the height of the bulk material and reposition the suction nozzle accordingly. The disadvantage of this flexibility: As the length of the telescopable spout increases, throughput decreases. 17 Bühler

18 Energy consumption. Mechanical unloaders have a lower energy consumption per ton compared to pneumatic unloading systems. Thanks to a reduced design with few components and a lower conveying speed, the energy consumption of mechanical unloading systems like the Buhler Portalink is significantly lower. By comparison, the energy consumption of mechanical unloaders is approximately kwh per ton. where pneumatic systems average roughly kwh/t; older systems even require more than 1 kwh/t. Depending on conveying capacity and local energy prices, mechanical unloading systems can save the user tens of thousands of Euros each year. In light of the continuing trend toward higher energy prices, it stands to reason that in the future, mechanical unloading systems may also become more attractive for lower capacities above all in countries where energy is expensive. High levels of specific energy consumption also have a negative impact on the overall power supply of an installation and on costs for the provision of energy. The necessary investment costs, as well as the annual increases in electricity rates, are often overlooked in calculating the overall costs of a system. In this regard, mechanical unloading systems are clearly superior to pneumatic solutions. 18 Bühler

19 Energy usage throughout the hatch 19 Bühler

20 Product protection. The overall high product quality leads to higher margins than with pneumatic unloading systems a financial aspect that shouldn't be underestimated in light of increasing grain prices. Mechanical: Mechanical solutions like the Buhler Portalink/Portalino unload bulk material at a constant low velocity. This not only reduces wear and the maintenance costs of the system, but also ensures that especially sensitive grain is unloaded in an exceedingly gentle manner. In this way, damage to the product is minimized and financial losses caused by high reject rates are avoided. Pneumatic: The physical properties of pneumatic solutions require the conveying speed to be higher than that of mechanical systems. The resulting higher maintenance costs are not the only disadvantage; critical disadvantages also include higher reject rates and lower product quality, which in turn leads to lower market prices. Additionally, greater system wear results in reduced unloading throughput. 20 Bühler

21 21 Bühler

Portalink Mechanical ship unloader RSH

Portalink Mechanical ship unloader RSH Portalink Successful, proven engineering Buhler your Partner Mechanical ship unloaders from Buhler designed to handle a wide range of free-fl owing bulk materials