TECHNOLOGY DEMONSTRATIONS OF AEA TECHNOLOGY ENGINEERING SERVICES (AEAT) FOR UNPLUGGING PIPELINES AT THE FIU-HCET TEST SITE
Plugging Prevention and Unplugging of Waste Transfer Pipelines
Principal Investigator:
M. A. Ebadian, Ph.D.
Collaborators:
Y. Sukegawa
M. Allen
R. Silva
P.V. Skudarnov Ph.D.
C.X. Lin, Ph.D.
FloridaInternationalUniversity
Hemispheric Center for Environmental Technology
Prepared for:
U.S. Department of Energy
Office of Environmental Management
Office of Science and Technology
DISCLAIMER
This report was prepared as an account of work sponsored by an agency of the United States government. Neither the United States government nor any agency thereof, nor any of their employees, nor any of its contractors, subcontractors, nor their employees makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe upon privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States government or any agency thereof.
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ACKNOWLEDGMENTS
The results presented in this report were obtained from work supported by the U.S. Department of Energy (DOE), Environmental Management (EM), Office of Science and Technology (OST) under Grant No. DE-FG21-95EW55094. The Principal Investigator and the associate researchers at the HemisphericCenter for Environmental Technology would like to thank Peter W. Gibbons, manager of Retrieval Technology Integration, DOE Tanks Focus Area (TFA), for his guidance and suggestions. The authors are also grateful for the useful discussions with Dr. Fadel F. Erian and Mr. Michael Rinker at Pacific Northwest National Laboratory (PNNL). We would especially like to thank the DOE-OST for their support and encouragement throughout this research.
HCET-1998-M004-003-30
TABLE OF CONTENTS
Executive Summary
1.0 Introduction
2.0 Task Description
2.1 Technology Description
2.2 General Plug Information
3.0 Technology Demonstration Details
Appendix A
Appendix B
HCET-1998-M004-003-30
Executive Summary
U.S. Department of Energy (DOE) sites, such as Hanford and the Savannah River Site (SRS), need safe and efficient technologies for its tank farm operations that include waste retrieval and transport of slurry waste through pipelines. As the waste tank clean-up gathers momentum, there is an increased potential for the waste transfer lines to become plugged. Plugged pipelines represent a considerable hazard and loss of time and money. In order to meet the DOE’s sites need for waste transfer pipeline unplugging technologies, FloridaInternationalUniversity’s HemisphericCenter for Environmental Technology (FIU-HCET) was contracted to identify and evaluate technologies for pipeline blockage locating, reaching, and dislodging using technology demonstrations on full-scale test beds.
During April FY00, the National Energy Technology Laboratory (NETL) issued a request for proposal (RFP) for a technology demonstration in collaboration with DOE-TFA and FIU-HCET. AEAT Engineering Services, Inc. (AEAT) was awarded a contract to demonstrate their innovative “wave erosion” technology. The pipeline blockage removal technology system demonstrated by AEAT is a promising pipeline unplugging technology that shows immense potential toward use in long pipelines that have drained down below a blockage. The technology is in the developmental stage, and a prototype unit was demonstrated. Following are the benefits offered by this technology:
- The setup does not discharge water until the blockage is cleared, therefore minimizing the amount of liquid added.
- The technology negotiated up to 11 elbows before the blockage. (Unlike mechanical devices, this method is unaffected by elbows in the pipeline.)
- It has a potentially short mobilization and demobilization time once an adaptive jumper is fabricated.
- The wave action method was effective for most tested blockage types. This technology may be used to deliver a chemical solution to the blockage; thus, a combination of wave action with chemical dissolution should be considered for future applications where a solvent may be of assistance in loosening a blockage.
- Positive and negative pressure cycles act to loosen a blockage.
This document presents results for pipeline unplugging technology demonstrations at FIU-HCET. The Test Assessment Site and the technology tested are described herein. The results are presented in tabular format and contain pertinent technology demonstration statistics and information such as technology utility requirements and maturity of technology. Demonstration statistics provide information about technology performance, such as mobilization and demobilization times, reaching time, tool recovery time, total unplugging time, effectiveness of the technology, plug composition and location, and number of elbows traversed.
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1.0 Introduction
FIU-HCET has constructed three test beds to demonstrate and evaluate the capabilities for blockage reaching, unplugging, and detecting technologies in pipelines. The three test beds were based on the Functions and Requirements provided by DOE sites. They are representative of the actual pipelines at DOE sites, including SRS, Hanford, and Oak Ridge. All demonstrations are conducted under standardized, non-radioactive conditions.
2.0 Task Description
This section describes the test beds, the general placement of the plugs in the pipeline, the types of plugs, the technology used, and the key results from the demonstration.
2.1 TECHNOLOGY DESCRIPTION
AEAT technology is based on a fluid wave-action principle, which operates much like ocean wave-action on beach erosion, possibly aided by use of a solvent, coupled with positive and negative pressure pulses that tend to loosen the blockage. It can operate on a long pipeline that has drained down below a blockage. The system consists of a water/solvent tank, pressurize/vacuum vessel, fluidic control unit, vacuum finishing pump, and an air-operated jet pump eductor (see Figure 1).
Figure 1. AEAT equipment setup. / Figure 2. Fluidic control unit and the jet pump connected to the air hoses.First, the jet pump eductor and, if needed, a vacuum pump are used to evacuate any air that may be present in the pipeline below the blockage in elevation. Once a vacuum has been established, a ball valve is opened, and water or other solvent is allowed to back fill the pipeline. The fluidic control system (see Figure 2) is then used to provide pressure and vacuum to the fluid in a cyclic manner. During the drive cycle, fluid impacts the blockage as a wave flowing under the air bubble at the high point at the blockage, and during the suction cycle, water retreats away from the blockage. These cycles are repeated many times until the blockage is eroded away. The frequency and duration, as well as the pressure, of each cycle can be controlled via the fluidic control unit. This coupled with the dissolving action of a selected solvent and the physical action of the vacuum and pressure cycles works to both erode and loosen the blockage.
2.2 GENERAL PLUG INFORMATION
A total of 12 1-ft long blockages were tested on test bed # 2 (see Figure 3). Eleven plugs were placed in a capped test section at a distance of approximately 255 ft from the access port, and one blockage at the end of the 1765-ft pipeline. The test section was capped due to the inability of short (one foot long) test plugs to adequately hold a vacuum against the AEAT system. The blockage sections were inclined approximately 5 with respect to the ground to simulate a graded pipeline that has drained down below a blockage (see Figure 4). Blockages were made from a variety of materials, such as Bentonite, K-mag, Kaolin clay, and sand (see Table 1). In order to observe and measure the rate at which the blockage was being physically eroded, a section of clear PVC pipe containing the blockage was attached to the pipeline (see Figure 5).
Figure 3. Diagram of AEAT Demonstration on Test Bed # 2.
The percentage (by weight) of plug/scale removed was determined by weighing the plugs/pipe sections before and after each demonstration. A removal effectiveness of 100% would indicate the technology was completely successful in removing the plug. Partial removal and/or dislodging of the plug were recorded as partially successful. The purpose of these tests was to compare erosion rates since the blank flange at the end of the pipe, placed to allow development of a full vacuum, prevented the suction and pressure cycles from dislodging and expelling the blockage as a whole.
3.0 Technology Demonstration Details
The fluidic system demonstrated by AEAT is a promising innovative pipeline unplugging technology that has a potential of being deployed at DOE sites. One of the benefits of this technology is that the setup does not discharge water until the blockage is cleared, minimizing water required. Also the technology is independent of the number of elbows before the blockage, and it has a short mobilization and demobilization time (once adapter jumpers have been fabricated). However, the technology is still in the developmental stage, and the unit demonstrated at FIU-HCET is a prototype unit. Table 1 represents in a tabular form the details of the demonstrations carried out at FIU-HCET. All the demonstrations were performed on Test Bed #2 with access port diameter of 3 in. AEAT technology was non-intrusive, and it required very little operator effort. It may be operated remotely through the control panel.
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Table 1.
Demonstration Information and Statistics for AEAT Technology
Blockage Distance (ft from entry point) / 255 / 255 / 255 / 255 / 255 / 1765
Water Pressure (psi) / ~7 / ~7 / ~14.5 / ~29 / ~29 / ~58to72
Number of Elbows Traversed / 6 / 6 / 6 / 6 / 6 / 13
Reaching – Distance Reached (ft) / 255 / 255 / 255 / 255 / 255 / 1765
Time Equipment Operated (hrs) / 2.51 / 0.55 / 4.27 / 3.38 / 4.5 / 23.06
Unplugging Effectiveness for that Period (% by mass of total blockage removed) / ~77 / ~17 / ~42 / ~71 / ~100 / ~100
Total Time for unplugging (hrs.) – extrapolated to 100% unplugging effectiveness and assuming unplugging is a linear process / 3.26 / 3.23 / 10.17 / 4.76 / 4.5 / 23.06
Observations on Unplugging / Blockage first dislodged and then gradually dispersed until complete unplugging. / Blockage first dislodged and then gradually dispersed until complete unplugging/ different wave frequency and pressures. / Blockage first dislodged and then gradually dispersed until complete unplugging/ different wave frequency and pressures. / High erosion rate. / High erosion rate. / Weak drive cycle. Unplugged 40-50%, and then the rest was blown out of the pipe with higher pressure water.
Table 1.
Demonstration Information and Statistics for AEAT Technology (continued)
Blockage Distance (ft from entry point) / 255 / 255 / 255 / 255 / 255 / 1765
Water Pressure (psi) / ~7 / ~29 / ~29 / ~29 / ~29 / ~29
Number of Elbows Traversed / 6 / 6 / 6 / 6 / 6 / 6
Reaching – Distance Reached (ft) / 255 / 255 / 255 / 255 / 255 / 255
Time Equipment Operated (hrs) / 2.78 / 5.37 / 7.08 / 3.9 / 1.91 / 4.92
Unplugging Effectiveness for that Period (% by mass of total blockage removed) / ~57 / ~49 / ~100 / ~4 / ~57 / ~90
Total Time for unplugging (hrs.) – extrapolated to 100% unplugging effectiveness and assuming unplugging is a linear process / 4.88 / 10.96 / 7.08 / 98.5 / 3.35 / 5.47
Observations on Unplugging / Blockage first dislodged and then gradually dispersed until complete unplugging / Relatively high erosion rate. / Relatively high erosion rate. / Gradually leveled blockage into sloped layer and freed blockage. / Gradually leveled blockage into sloped layer and freed blockage. / Relatively high erosion rate.
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The wave action methodology employed by AEAT was effective for erosion of most blockage types; however, the unplugging time due to erosion alone was relatively high compared to other methods. This is due to the fact that the unplugging technology was limited to erosive process of wave action alone because of the need to cap the far end of the pipe in order to achieve needed vacuum. Five bulky and clay-like types of blockage materials were placed in the pipeline test section, and the end of the pipeline was capped since the vacuum could not be achieved using the blockage material alone. The erosion efficiencies varied greatly depending on the blockage materials (seeFigure 6). Wave action successfully reached blockage at approximately 1765 ft, and unplugging was eventually achieved. However, the wave energy was very weak and only partially reached the blockage (mainly due to vacuum limitations). In order to have better wave action in longer pipes, a stronger vacuum is needed to reduce the size of the air bubble at the high end of the pipe below the blockage. This technology may also be used to deliver a chemical solution to the blockage; thus, a combination of wave action with chemical dissolution can be considered. Further testing of this technology is planned for FY01. These tests will include comprehensive testing of erosion coupled with pressure cycles constrained by a capped pipe.
Figure 6. Blockage Erosion Rate vs Blockage Type.[7]
The highlights of the wave erosive action AEAT technology for unplugging of pipelines (representative of DOE sites) are summarized in Table 2.
Table 2.
AEAT Technology Summary
Benefits /
- Short mobilization and demobilization times possible with an adaptive jumper.
- Can be used to deliver chemical solvent to the blockage where a solvent may be of assistance in loosening a blockage.
- Can be applied to the section of the pipeline that has drained down below the elevation of the blockage.
- System works under relatively low drive pressures (100 psi tested).
- Technology can negotiate many elbows. (Unlike mechanical devices, this method is unaffected by elbows in the pipeline.)
- Technology can be operated remotely.
- No water discharged until the blockage is cleared, therefore minimizing the amount of liquid added.
- Location of the blockage can be determined by the amount of water required to back-fill the pipeline.
Limitations /
- Length of reach in an empty pipeline is limited by the strength of the vacuum pump.
- Positive and negative pressure cycles acting to loosen a blockage were effective for most blockage types; however, unplugging time is relatively high as compared to other methods when considered without the effect of vacuum and pressure cycles.
- Although the technology achieved its primary goals for the demonstration, the technology is still in its infancy and needs further development.
Data Sensitivities / Initially, the technology was able to easily achieve vacuum in the 255-ft pipeline. Since the desired vacuum pressure could not be achieved for later blockage tests due to leak-by at the blockage, the end of the test pipeline section was capped. This is because the vacuum could not be achieved with a blockage material alone. Initial difficulties with the vacuum system will be solved by installing a new vacuum pump and a jet pump.
Wave action successfully reached a blockage at approximately 1765 ft. However, the drive cycle was very weak, and the waves only partially reached the blockage (mainly due to vacuum limitations). Unplugging was eventually achieved, but 40-50% of the blockage material still remained at the end of the cycles (see Figure 6 for blockage erosion rate vs blockage type). Final clearing of the blockage was achieved by using water pressure to blow the blockage out of the open end of the pipe after it was uncapped. The final unplugging time (~ 23.06 hours) for this blockage was extrapolated based on ~50% completion. A stronger vacuum will maximize the effective reaching range of the system.
Appendix A
Description of Test Bed #2: horizontal long pipeline (1765 ft long)
Test bed #2 was designed to demonstrate how far a technology could access a blockage in a long pipeline negotiating 90o bends. This test bed is constructed of a 3-inch, Schedule 10, carbon steel pipe having an inside diameter of 3.25 inches. The access point is at 3-ft elevation from the ground with either a 3-inch access pipe or a Hanford connector as an interface. The total length of the pipeline is 1765 ft with both left- and right-turning 90o elbows (see Figure A1). The schematic diagram of test bed #2 is shown in Figure A2.
Figure A1. Test bed #2 – horizontal pipeline. / Figure A2. Schematic drawing of test bed #2.1
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Appendix B
TECHNOLOGY INFORMATION (GENERAL)Technology Name / Prototype
Maturity of Technology
(Choose ONE of the following options) / Commercially available
- Prototype
Utility Requirements for Technology Model / Electricity – 110 VAC @ 15A
Water source - 6 GPM @ 60 psi
Air supply - 375 CFM @ 75 psi
Portability Options
(Select all that apply) / 1 person needed to move from truck
2 people needed to move from truck
Forklift needed to remove from truck
Truck/trailer mounted
MANUFACTURER INFORMATION
Name and Address / AEA Technology Engineering Services, Inc.
184B Rolling Hill Road
Mooresville, NC 28117
Phone Number(s) / (704) 799-2707 / NA
Fax Number / (704) 799-6426
Web-site /
E-Mail /
Services Available
(Select all that apply) /
- Service provider
Will train site users, # hours :
NA / hours
Photographs/Video / Check each of the following that was included in package to FIU-HCET:
Photographs, (number provided to FIU-HCET)
Video, (number provided to FIU-HCET)
VENDOR INFORMATION
Name and Address / AEA Technology Engineering Services, Inc.
184B Rolling Hill Road
Mooresville, NC 28117
Phone Number(s) / (704) 799-2707 / NA
Fax Number / (704) 799-6426
Web-site /
E-Mail /
VENDOR SUPPLIED INFORMATION
Required Personnel for Operation / State number of each required for basic operation of equipment:
- Equipment operators: 1
- Technicians: 1
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[1] K-W: K-mag (90%) and water (10%) mixture
[2] KC-W: Kaolin clay (70%) and water (30%) mixture
[3] B-S-W: Bentonite (30%), sand (30%), and water (40%)
[4] KC-S-W: Kaolin clay (40%), sand (40%), and water (20%)
[5] CS-W: Coarse sand (90%) and water (10%)
[6] KC-W: Kaolin clay (90%) and water (10%)
[7] These values are extrapolated based on 100% unplugging effectiveness and assuming a linear erosion rate for the blockage. Extrapolated values are then averaged based on the number of blockages tested for each type.