Unloading Operations Research Articles

Organic petrographic evaluation of carbonaceous material in sediments of the Kinnickinnic River, Milwaukee, WI, U.S.A.

This study examines the use of organic petrology techniques to quantify the amount of coal and carbonaceous combustion by-products (i.e., coke, coal tar/pitch, cenospheres) in sediments taken from the Kinnickinnic River adjacent to the former site of the Milwaukee Solvay Coke and Gas Company. These materials are of concern as contaminants like polycyclic aromatic hydrocarbons (PAHs) are known to readily adsorb to coal and combustion byproducts. Kinnickinnic River sediment samples (n = 36) ranging in depth (1–11 ft.) were collected from eight core locations to quantify and characterize carbonaceous material in the sediments. To determine the amount (vol%) of organic particulates, U.S. Geological Survey (USGS) modified the existing ASTM D2799 using the following categories: coal, coke, coal tar/pitch, inertinite organics, plant material, cenospheres, and mineral matter. Coal fragments were subdivided by rank using vitrinite reflectance (Ro, %) and organic components were further subdivided into the size fractions of coarse (250–1000 μm), fine (63–250 μm), and very fine (<63 μm). Of the 36 samples analyzed, concentrations of coal, coke, and coal tar/pitch ranged from 0 to 18.2 vol%, 0 to 32.0 vol%, and 0 to 2.6 vol%, respectively, with the highest concentrations occurring near point sources (e.g. discharge pipe and coal unloading operations). Samples that were furthest upstream and downstream from the Solvay site exhibited a marked decrease in particulate organics, with exception of one upstream location which had 19.8 vol% coke. Overall, the modified ASTM method provided a means to quantify the abundance of carbonaceous material present in the sediments. Petrography and total PAH concentrations did not provide a clear correlation to organic matter type or size fraction but the samples with the highest vol% organic matter in each core generally corresponded to the sample with the highest bulk PAH content.

Influence of a cargo plan on the container ship port turnaround time

Nowadays, with patented technologies for the production of goods, the possibility of reducing their cost in order to maintain a competitive position in the commodity markets is supported by the rational organization of transportation. Thus, the transport component in the final cost of transported goods is reduced. At the same time, when using the same handling, lifting and transporting equipment from a limited number of global manufacturers, the possibility of reducing the cost of transport operations (both shipping and handling, including loading/unloading) depends only on their rational use. One of the mechanisms for rationalizing the loading and unloading operations carried out by container terminals is the rationalization of cargo plans of the serviced container ships. The versatility of their development is determined, first of all, by high requirements for the safety of navigation, which determine the provision of the necessary stability, unsinkability, the absence of a heel and difference that interfere with the work, the required sitting of the ship in the water, etc. On the other hand, the rational placement of containers in the slots and on the hatches covers of the container ships, corresponding to the voyage rotation (the sequence of visiting terminals on the trip in progress), provides an increase in the share of productive movements of handling, lifting and transporting equipment, reduces the required time for a ship to be under loading and unloading operations, which reduces the time of a group of ship trips on a string. Such calculations are complicated by the fact that the handling equipment used during the loading and unloading operations on a separate ship operates conditionally autonomously, each unit - for its own section of the ship (“bay”). Thus, the task can be solved only in a complex manner, coupled with the task of cranes allocation over the berth. The paper studies the issues of cargo planning of liner container ships from the standpoint of reducing the time of ship’s turnaround time due to rational assignment and use of port handling equipment.

Ship-unloading scheduling optimization for a steel plant

A ship-unloading scheduling problem (SUSP), also called “sequencing ship” problem arising from a large steel plant with bulk material port is studied in this paper. Raw materials such as iron ore, coal and stone are transported to the steel plant by ships. Each ship has an expected departure time based on a contract between the steel plant and ship-owner. If the steel plant cannot effectively schedule the unloading operation of the ship to make it leave the port before its expected departure time, a demurrage penalty cost which increases with the delay will be charged to the steel plant by the ship-owner. SUSP is to find an optimal schedule for these raw material ships so as to minimize the total demurrage costs within a given planning time horizon. The problem is formulated as a mixed integer programming, and can be regarded as a flexible job shop scheduling problem, where the ships are regarded as the jobs and the belt conveyors as the machines. A column generation approach is proposed for solving the optimization model. The computational results on the real-world data obtained from the steel plant are compared with CPLEX to verify the effectiveness and merits of the proposed model and solution. The proposed optimization technique has great potential to be applied in the steel plant, and it may save 20 million of CNY caused by the delay cost per year.

ANÁLISE QUALITATIVA DO USO DOS RECURSOS EMPREGADOS NO PROCESSO DE DESCARGA DE GRANEL SÓLIDO EM UM PORTO PÚBLICO DO NORDESTE (BR)

O objetivo principal deste trabalho é levantar e discutir os recursos identificados em uma operação de descarga realizada em um porto público do Nordeste (BR). A pesquisa foi pautada em uma abordagem qualitativa e as análises foram realizadas a partir de observações e entrevistas com os principais gestores responsáveis pelas empresas que participam da operação de descarga ativamente, baseando-se os resultados em suas percepções. Com principais resultados, foi possível discutir as falhas e problemas presentes na operação com relação ao gerenciamento dos recursos, além da percepção incompleta dos gestores com relação à gestão destes recursos por suas empresas.

Experimental Investigation of Vertical Downward Two-Phase Flow in Annulus

Abstract A limited amount of work exists on gas–liquid flow in vertical pipe annulus, and, to the knowledge of the authors, there is no work on the literature to characterize vertical downward two-phase flow in pipe annulus. In the petroleum industry, downward two-phase in annulus is encountered on liquid-assisted gas-lift (LAGL) unloading and production operations. This study presents experimental data for pressure gradient, liquid holdup, and flow regimes for vertical downward two-phase (air and water) flow in pipe annulus. Also, the applicability of two-phase flow models are evaluated. The experimental results show that the liquid holdup is consistently higher for downward flow in annulus than in pipes for the annular flow regime, and these differences are as high as 45%. When the flow regime map for downward flow in annulus is compared with the ones in the literature for flow in pipes, it is observed that the intermittent flow in pipes occurs at lower liquid velocities than flow in annulus. The comparison between experimental data and model results also shows some discrepancy for liquid holdup and pressure gradient. These differences are high for annular and intermittent flow regimes, with errors of 100% for the liquid holdup and 200% for pressure gradient. However, the errors for bubble flow regime are much smaller, generally lower than 20%.

System for Capturing Vapors of Oil and Oil Products in the Course of Loading and Unloading Operations and in Transportation

The constructions and operating principles of devices for reducing losses due to evaporation of oil and oil products in the course of loading and unloading operations and transportation of oil and oil products are considered. The effectiveness of the proposed system derives from preventing the entry of atmospheric pollutants and moisture into the tank cars, maintenance of the quality of the oil products, increasing the time devoted to cleanout of the storage tanks and tank cars, reducing losses of oil products, and protecting the environment against harmful discharges of vapors of oils and oil products.

An Optimization Approach for a Complex Real-Life Container Loading Problem

We consider a real-world packing problem faced by a multinational logistics company that loads and ships hundreds of trucks every day. For each shipment, the company needs to select the cargo to transport from a set of heterogeneous boxes available at the warehouse, and load it into the truck. This leads to a container loading problem (CLP) where the goal is to maximize the value of the cargo while satisfying a number of practical constraints to ensure safety and facilitate cargo handling, including customer priorities, load balancing, cargo stability, positioning constraints, and limiting the number of unnecessary unloading operations during multi-shipment deliveries. Although some of these constraints have been considered in the literature, our CLP is particularly challenging because: (i) reducing unnecessary unloading operations while maximizing value are conflicting objectives, and (ii) the unloading constraints are new and hard to handle, especially when combined with the other constraints we account for. We tackle this problem by proposing a randomized constructive heuristic that iteratively sorts the items based on multiple criteria, then perturbs the sorting by using randomization, and finally constructs the packing while complying with all the constraints. We also propose dual bounds based on CLP relaxations. On large-scale industry instances, our algorithm runs in a few seconds and outperforms the company's own solutions (constructed manually by the warehouse personnel) and those provided by commercial software, in terms of both cargo value and constraints handling.

The Systematic Optimization of Train Formation in Loading Stations

This paper presents the formulation of a train formation problem in rail loading stations (TFLS) from the systematic perspective. Several patterns of train formation are analyzed thoroughly before modeling, including direct single-commodity trains, direct multi-commodity trains created in the loading stations, and direct trains originating from reclassification yards. One of the crucial preconditions is that the loading and unloading efficiencies in the loading stations and the relational unloading stations are symmetric. Based on this, a non-linear 0–1 programming model is designed with the aim of minimizing the total car-hour cost incurred by the loading, unloading, and reclassification operations, and the commercial software Lingo is employed as the solving approach. A small-scale example is carried out first to illustrate the validity of the presented model and the effectiveness of the proposed method. Then, a series of numerical cases are devised to test the model and solving approach. The computational results show that our model can be regarded as a theoretical foundation of the TFLS problem.

Grapho-analytical modelling of technological chain of logging operations in dynamic natural and production conditions

Different variants of technological chain can be organized in logging process. Water or land types of transport can be used for transportation of timber. The use of timber landings where wood can be processed also increases the number of multiple variants of technological process. Performance of operations in various natural and production environment differs in productivity and material costs. Production efficiency depends on the choice of technology of logging operations in dynamic natural and production environment. The given research suggests the variant of the grapho-analytical model for solution of the set task. Detailed graphic models of transportation of wood from logging unit to consumer, loading /unloading and processing operations at the intermediate and lower timber landing are developed. They show possible options of technological chains of logging process. Mathematical dependences are shown on the basis of the problem of finding the maximum flow of minimum cost in the suggested dynamic network. They define the conditions for solution of the set problem.

Study on distributed lithium-ion power battery grouping scheme for efficiency and consistency improvement

The service life, safety, and capacity of lithium-ion power battery packs relies heavily on the consistency among battery cells. Grouping is an effective procedure to improve consistency by screening cells with similar performance and assembling them into an identical group. Battery grouping can be achieved via clustering techniques based on characteristics like static capacity, internal resistance etc. The dynamic characteristics-based method considers the battery performance during the entire charging-discharging process and has become one of the most promising grouping method. However, it suffers from high computational complexity. Nowadays, facing stricter quality standards and the increasing demand for battery products, existing dynamic characteristics-based grouping scheme cannot meet the performance and time requirement of the modern high-quality, large-scale battery manufacturing. In this paper, a novel grouping scheme based on distributed time-series clustering is proposed to match the need of both efficiency and consistency improvement. The proposed scheme designs an effective cloud-edge mode and utilizes an innovative two-stage trick to achieve parallel processing, which split the original centralized clustering approach into local clustering and global merging. The host computers for data acquisition and battery control are regarded as distributed edge computing resources to implement local clustering on the acquired battery discharging voltage sequence set. Cluster contours are extracted via a denoising contour extraction algorithm considering the irregularity of the discharging voltage sequences. The results of the above preliminary processing are uploaded to a cloud data center. A pragmatic merging scheme based on an integrated merging indicator is established to solve the decision-making problem of global merging on the cloud data center. The final global cluster set is transmitted back to host computers to instruct cell unloading operation. Experimental results based on real battery discharging voltage sequence data suggest that the proposed scheme can reduce the inconsistency rate by 43.56% and the time cost by 92.87%. The computing efficiency and resource utilization rate of the distributed scheme is much higher than the centralized scheme. Meanwhile, compared with three existing advanced grouping approaches, our scheme perform the best in reducing inconsistency rate. (C) 2019 Published by Elsevier Ltd.

The quay crane scheduling problem with non-crossing and safety clearance constraints: An exact solution approach

This paper considers the Quay Crane Scheduling Problem (QCSP) with non-crossing and safety clearance constraints for a single vessel. The problem determines the order of unloading and loading operations that a specific number of quay cranes (QCs) perform to serve a vessel in minimum time. The QCs move on a single rail and therefore cannot cross each other, and every two consecutive cranes must leave a specific safety distance between them. Due to the difficulty of this problem, most researchers have used heuristics to solve it. However, the QCSP is normally used as a building block of bigger ports’ optimization problems that are very difficult to solve without some decomposition techniques like Lagrangian relaxation. For these methods to succeed, the sub-problems must be solved to optimality in reasonable computational time. This paper presents an improvement on a recent novel formulation for the problem, followed by a new exact and computationally fast technique to solve it. The technique is a two-step approach initiated by a partitioning heuristic and terminated by a Branch and Price algorithm. Through computational experiments, we demonstrate that the proposed solution approach can solve real-sized cases in a fast computational time and has low sensitivity to all parameters. Finally, we introduce a method, formulated as a traveling salesman problem, to acquire operationally practical solutions by minimizing crane re-positioning movements and accounting for crane initial positions.

A Novel Workflow for Using Fiber-Optic Telemetry-Enabled Coiled Tubing in Candidate Selection

Formation damage is an undesirable operational and economic problem that can occur throughout the lifecycle of oil and gas wells due to several reasons such as using incompatible fluids during workover operations, fines migration, clay swelling, emulsions formation, and scale and organic depositions. Also, newly drilled wells sometimes do not produce optimally due to the damages caused by the drilling fluids. Therefore, addressing formation damage issues to ensure optimum recovery of hydrocarbons needs more efforts on identifying the damage mechanism and quantifying the skin factor. Skin factor is a dimensionless number that reflects the production impairment due to near-wellbore reduction of permeability. So, if this number is zero it means the well is intact, however; if this number is positive that means the well is damaged. The workflow presented in this paper focuses on the use of fiber-optic telemetry-enabled coiled tubing (FOTECT) for production enhancement in real-time by quantifying skin factor, estimating the flow potential and determining the candidate wells for matrix stimulation. This new technology can deliver pressure data in real-time during a typical unloading operation that could be further used in well test analysis for estimating key reservoir properties such as skin (S), flow capacity (Kh), drainage area (A) and initial reservoir pressure (Pi). The new technology reduces the operational time required for well test analysis compared with conventional downhole recording systems (DHR) by two-fold while enabling the performance of an acid treatment in the same run. Moreover, in this study a workflow and user-interface software using java language were developed to execute the workflow through a two-step streamlined process: 1. Assessing the well damage through quantifying the skin value from pressure transient analysis (PTA) utilizing the downhole pressure data acquired from coiled tubing in real-time. 2. Inflow performance relationship (IPR) construction of the well using Vogel’s correlation and productivity index equation under the current condition and under ideal condition (Zero skin) to assess the feasibility of a stimulation treatment. The paper will present the application of this technique on simulated field data to show how FOTECT could be used to diagnose and treat the well in the same run. The output obtained from the developed software will be compared against the output of an industry popular well-test suite (Sapphire). Also, a case study in which this technology was used for pressure transient analysis for artificial lift design will be presented to show the applicability of this novel approach and to prove it can yield matching results with conventional techniques in a more efficient way. From the simulated data the developed software estimated the skin factor to be nine from both build-up and draw down analysis, which was later matched by Sapphire commercial Suite; moreover, it was shown that the current production rate of 792-BPOD can be increased to 1722-BOPD post a successful stimulation treatment.

Estimating transport safety of propane-butane mixture with event and fault trees and probability methods

The threat of people as a result of delivery vehicle fire handling 11 kg and 33 kg bottles with propane-butane, due to leakage of these bottles was estimated. The probability of unsealing LPG bottles with gas during the year at loading, unloading and transport operations in carrier trade company was determined. Partial and total risk of serious driver injuries and the risk of death in the event of a fire in open load-carrying body of the car and tire damage was estimated. The risk assessment uses the methods of the event and fault tree as well as the probabilistic method.

Sustainable refrigerated food transport: searching energy efficient routes

Despite the growing importance of refrigerated food transportation and attention paid to the related sustainability issues, few studies have introduced energy efficiency to guide decision making at operational level. In this research, refrigeration loads are introduced when evaluating fuel consumption for palletized frozen food deliveries from a central refrigerated warehouse, in order to select the best route. In particular, infiltration loads during unloading operations are evaluated basing on the most recent models, as well as transmission loads both during travelling and stops at clients, taking into account changes of outdoor temperatures. A minimum fuel consumption multi-period optimisation model has been developed and solved by Constraint Programming and then applied to a local network of supermarkets. While the traditional minimum travel distance remains the best solution due to the greater impact of travel requirements on total fuel consumption with respect to refrigeration ones, a preferred direction to run the circuit has been highlighted, depending on the different outdoor temperature of time slots triggered during distribution.

Optimization of the Operating Parameters of Transport and Warehouse Complexes

Abstract It is necessary to select the optimization criterion in order to determine operation parameters of transport and warehouse complexes. We developed a procedure for determining the optimal parameters for operation of the complexes. It includes methods of calculating the optimal amount of loading and unloading mechanisms and stations. The research findings show that when calculating the optimal amount of loading and unloading mechanisms and stations it is advisable to take into account the ratio of intervals of the rolling stock arrival for loading and unloading and the standard duration of one unloading mechanism operation. In order to determine the optimal amount of loading and unloading mechanisms and stations in warehouse complexes, we propose a cost-based criterion in the form of minimum aggregate costs for loading and unloading operations incurred by transport and warehouse complexes and the downtime of rolling stock in the course of loading and unloading operations incurred by shipping organizations. It has been found that the saving of the total costs and losses incurred by carriers and the terminal to organize the unloading of vehicles using two loaders at one unloading station is 23 % as compared to the unloading at two unloading stations.

Stochastic modeling of unloading and loading operations at a container terminal using automated lifting vehicles

With the growing worldwide trade, container terminals have grown in number and size. To increase operational efficiency, many new terminals are now automated. The key focus is on improving seaside processes, where a distinction can be made between single quay crane operations (all quay cranes are either loading or unloading containers) and overlapping quay crane operations (some quay cranes are loading while others are unloading containers). Using a network of open and semi-open queues, we develop a new integrated stochastic model for analyzing the performance of overlapping loading and unloading operations that capture the complex stochastic interactions among quayside, vehicle, and stackside processes. The analytical model is solved using an iterative algorithm based on the parametric decomposition approximation approach. The system performance is tested at varying container traffic levels. We find that the percent absolute errors in throughput times compared to simulation are less than 10% for all cases. Using these integrated models, we are able to generate design insights and also rapidly analyze what-if scenarios. For example, we show that the best yard layout configurations for single (either loading or unloading) operations and the best for overlapping (both loading and unloading) operations largely overlap. The best configurations have relatively few stack blocks and many rows per block. The model is generic and amenable to obtain other design and operational performance insights.

Rice Autonomous Harvesting: Operation Framework

This paper reports on an operation framework for autonomous rice harvesting. We developed an integrated algorithm for robotic operation and cooperation with farmworkers to automate each subsection of the harvesting and unloading process and of the processes that bridge them (homing and restarting). The algorithm was installed into a head‐feeding combine robot. The robot followed a target path based on its absolute position and orientation, planning a counterclockwise spiral path in a rectangular paddy field, and returned to a position close to a farm road when its grain tank was filled to a specified level. The grain unloading operation was automated using a machine vision system. As the restarting process (return to harvesting) was also automated, the combine robot was able to harvest a rectangular field autonomously by cyclically repeating the harvesting, homing, unloading, and restarting operations. Under field conditions, the robot was able to follow the target path within tolerable lateral and azimuth errors while harvesting rice successfully, and to unload the harvested grain into a wagon without spillage. The root mean square error of the lateral and azimuth errors during harvesting were 0.04 m and 2.6°, respectively. In the homing operation, the robot returned to a given line within ± 0.1 m and aligned its heading to the direction of the line within ± 4°. The robot recognized the arbitrarily parked wagon and positioned its auger spout at the target point with a respective horizontal and vertical accuracy of ± 0.2 m and ± 0.3 m. Harvesting time accounted for 50%–60% of the entire robotic operation. Homing scheduling and dispatch control for the wagon were found to be of importance for developing a more efficient robotic operation.

Improvement on Chemical Accident Risk of Loading or Unloading Facilities for Hazardous Chemical Vehicles

환경부 화학물질안전원에서 운영하고 있는 화학사고 통계시스템인 화학안전정보공유시스템(CSC, Chemical Safety Clearing-house)을 통해 국내 화학사고 발생현황을 조사하였다. 2012년 9월에 발생한 구미 불산사고 이후 환경부에서 화학사고 관리를 일원화하여 2013년 이후 통계치가 신뢰도가 높다. 2013년부터 2016년 8월까지 발생한 화학사고는 총 370건으로 나타났다. 이 중 유해화학물질 운송차량에서 하역하거나, 적재하는 작업 중 발생한 화학사고는 13건으로 조사되었다. 대부분이 소량 누출사고였으나, 대량 유출사고도 일어났으며 인명피해도 발생하였다. 화학물질관리법에서는 이러한 사고를 예방하기 위한 취급시설 기준으로 트렌치를 설치하여 유출된 화학물질이 외부로 확산되지 않도록 규정하고 있다. 다만, 트렌치의 용량, 설치면적 등이 구체적이지 않아 실효성 측면에서 논란이 있어 시설기준을 개선할 필요가 있다. 이에, 본 연구에서는 유해화학물질의 운반차량 하역&#8901;적재장소의 트렌치 설치기준에 대한 최적화 기준을 제시하여 화학사고 피해를 최소화하는데 기여하고자한다.This study analyzed CSC(Chemical Safety Clearing-house) which is the statistical system of domestic chemical accidents, operated by National Institute of Chemical Safety. Among the total of 370 chemical accidents between January 2013 to August 2016, 13 cases occurred during loading or unloading operations of hazardous chemical vehicles. The Chemicals Control Act stipulated a standard on the safety facilities such as trenches to prevent the spilled chemical from spreading to the outside. However, the lack of details on trenches such as capacity and installation made the standard ineffective, which requires some improvements of the standard in precisely defining how to handle facilities. This study aims to present the optimization criteria used for installing trenches in loading and unloading places for the transport vehicles of hazardous chemicals and thus to contribute to minimize risk from chemical accidents in Korea.

EFFECT OF SHOCK LOADS ON THE STRENGTH OF IRON ORE PELLETS

At production of pellets one makes special demands on them, including the strength requirements. Pellets are subjected to the additional impact stresses in transfer units and ports; as a result there is not only their partial destruction but the decrease of strength properties in totality. The paper presents the research results on the destruction of pellets according to the classes, depending on the impact stress. When producing the pellets, it should be taken into consideration the probability of their softening in the results of loading and unloading ope rations during the transportation. Thereby, the safety factor increases with the increase of the number of loads and their height. For example, in the case from 5 to 10 loads the strength of the produced pellets should be not less than 285 kg/pellet; and when they are received by the consumers their strength should be not less than 200 kg/pellet. At the impact of stresses the compression strength of pellets decreases as the result of inner fractions formation. The primary strength of pellets should be more than the value, guaranteed by technical or contractual conditions.

Numerical study of wind actions applied to a low profile container crane

The target of this numerical study is to investigate the problems involved in the design of a low profile container crane exposed both to static and dynamic wind actions, in order to establish if these loads are dangerous when compared with the load induced by standard container load and unload operations. In the first step the work was performed by means of different schematizations of the wind load action allowed by the standards; the second step regarded the application of a real trend (velocity of wind versus time) obtained experimentally on a similar crane positioned in an Italian harbor. The results obtained in terms of maximum displacement depend on the crane load conditions and on the different schematizations used for the wind action. Using a variable wind pressure, the research shows that the effects of wind loads are greatly influenced by the natural vibration frequencies of both the structure and the elements that compose the structure.