Our site uses cookies necessary for its proper functioning. To improve your experience, other cookies may be used: you can choose to disable them. This can be changed at any time via the Cookies link at the bottom of the page.


Extrusion of thick wall pipes using a new bimodal PE 4710/PE 100 resin

 

Papers # 2018 Las-Vegas

Maintaining dimensions within specifications is problematic for the extrusion of large diameter thick-wall polyethylene (PE) pipe (> 75 mm wall) due to sag caused by insufficient resin melt strength. However, sag can be controlled through careful resin selection and optimization of the pipe cooling process. This paper describes the use of a new bimodal PE 4710/PE 100 HDPE resin which has been used to produce pipes up to 2,000 mm diameter and 127 mm wall thickness. The focus of this study is the production of 610 mm DR 7.3 (83.5 mm minimum wall) pipe per ASTM F2619. The cooling process was simulated using the chillWARE® software. Pipes were produced with all dimensions within specifications. Predicted temperature and viscosity profiles through the wall thickness are in agreement with the observed low sag. Analysis of the residual stresses are in line with the observed low toe-in and good pipe quality, which passed the quality control tests for short term hydrostatic pressure and fusion bend-back testing. Distribution of the carbon black was measured to be uniform across the wall thickness and good carbon black dispersion was achieved when analyzed per ISO 18553.

The extrusion of large diameter thick-wall polyethylene (PE) pipe is particularly challenging due to resin slump, or sag. The tendency for thick-wall pipe to sag due to its own weight during post-extrusion cooling makes it difficult to control pipe dimensions within specifications. The work discussed here examines the extrusion of 610 mm DR 7.3 pipe manufactured from a new bimodal HDPE PE 4710/PE 100 resin with excellent sag resistance. Analysis of the cooling process was performed using a software program, utilizing the thermo-physical properties (density, heat capacity, thermal conductivity) of the HDPE resin as its inout. This simulation software features an engine based on the finitedifference and finite-element methods to simulate axially-symmetric extruded polymer products such as pipes. The current work investigates a post-extrusion cooling process involving internal cooling for large diameter pipe. Results provided by the simulation are estimates of the through-thickness temperature distribution along the pipe during the cooling process, residual stresses, and resistance to sag. Simulated temperature profile results are verified by comparison with process temperature measurements. Simulation results in combination with the resin’s temperature dependent low shear melt viscosity are used to determine a sag indicator. It is shown that the geometrical stability of the pipe is greatly improved through the use of the new low sag resin. The influence of the cooling process on predicted residual stresses and resistance to sag are determined. Analysis of pipe quality in terms of hydrostatic pressure testing and bend-back on fusion joints, carbon black distribution and dispersion, and density across the pipe’s wall thickness are also discussed.

Related keywords : High Density Bimodal Polyethylene Pipe, Large Diameter, Thick Wall, Low Sag, Pipe Extrusion, Cooling Simulation.
Please note that the whole article content is available on PPCA website only


Related papers

2021 Amsterdam : A NEW GENERATION OF HIGH PERFORMANCE BIAXIALLY ORIENTED POLYETHYLENE AND POLYPROPYLENE PRESSURE PIPES

Author(s) : A. Taraiya, P. Degenhart, M. Soliman, M. Boerakker, R. Handstanger, R. Kleppinger

Since the introduction of polyolefins for pressure pipes, continuous improvements have been made to meet ever-higher demands on their performance and to expand their application window beyond their original scope, mostly based on new resin formulations. Today, we also continue to push the limit to provide better...

2021 Amsterdam : A TRADE ASSOCIATION EXPLORED

Author(s) : Drew Mueller, Peter Dyke

HDPE Pipe holds a dominant position in several markets in North America: natural gas distribution, oil patch, mining, landfill and geothermal. So why are polyethylene’s municipal water and wastewater market shares so much lower than these other industries? How has the polyethylene industry been successful in growing...

2021 Amsterdam : AN EVIDENTIAL APPROACH TO USE OF POLYETHYLENE PIPE FOR HYDROGEN FUEL GASES

Author(s) : Derek Muckle

A technical program has been undertaken to provide evidence on the suitability of polyethylene pipe and fitting systems for the distribution of hydrogen fuel gas. The underlying principle has been to evaluate material in the form of a pipe and to consider the performance of the pipe and of the welded jointing systems...

2021 Amsterdam : APPLICATION OF PP-R COMPOSITE REINFORCED PIPES IN HOT AND COLD WATER SYSTEMS

Author(s) : Lei Wang, Guozhi Xu, Qiaoping Qiu, Weihua Lu, Yanwang Han

PP-R (random copolymerized polypropylene) has been widely used in hot and cold water systems. However, the standard PP-R pipes have the disadvantages of a large high-temperature thermal expansion coefficient, an insufficient notched impact strength, and a low temperature and pressure resistance. In this paper, a new...

2021 Amsterdam : CHALLENGING THE 10% WALL THICKNESS RULE FOR HDPE MARINE PIPELINES

Author(s) : Ilija Radeljic, Ebbe Smith

HDPE pipe can be relatively easily scratched during the manipulation on the site, which is especially true for the marine pipelines. Installing the scratched marine pipe with the S bend method presents a risk and repair methods are usually performed. Currently, there is no standard defining the repair procedure, in...

2021 Amsterdam : CHEAPER AND BETTER NETWORKS REALISED WITH PRACTICAL DESIGN SOFTWARE

Author(s) : Andreas Moerman, Flip van der Valk, Mirjam Blokker KWR, Tjakko Haaijer, Jan Vreeburg,

Drinking water companies with ageing networks are facing vast amounts of drinking water network reconstructions during the coming decades. This development coincides with the energy transition, which puts pressure on the available space underground. These external drivers give drinking water companies an opportunity...

2021 Amsterdam : CONFIRMATION OF LONG SERVICE LIVES OF PE-PIPES UNDER HIGHER TEMPERATURES APPLYING CONVENTIONAL OVEN TESTS AND MODERN HIGH-PRESSURE AUTOCLAVE TESTS

Author(s) : Anja Armani, Helmut Zanzinger

PE-pipes are used in applications at temperatures higher than 40°C and long service lives like drainage pipes in landfill basal lining systems, drainage pipes in tunnels with high cover heights, geothermal applications, power plant technology, mining, underground cable protection pipes for power lines for...

2021 Amsterdam : DESIGN OF A DISTRIBUTED STRAIN MONITORING SYSTEM FOR HDPE WATER PIPELINES CROSSING AN EARTHQUAKE FAULT

Author(s) : Peter Hubbard, Linqing Luo, Andrew Yeskoo, Kenichi Soga, Krista (Moita) Araica, Gus Cicala, Marshall McLeod

Seismically active faults pose a risk to buried water pipelines that can be complicated to quantify. Fault type, slip rate, pipeline geometry, and soil conditions all factor into a complex soil-pipeline interaction. For critical pipelines that cross faults, high-density polyethylene (HDPE) has become an attractive...

2021 Amsterdam : DEVELOPMENT OF A RAPID AND INNOVATIVE IN-FACTORY PROCEDURE FOR TESTING THE PERFORMANCES OF PE PIPES CONTAINING VARIOUS PROPORTIONS OF RECYCLED POLYMER MATERIAL

Author(s) : Dominique GUEUGNAUT, Pascal AUSSANT, Romuald BOUAFFRE, Myriam BECHROURI

Concerns regarding the environment and sustainable development have revived interest in the reprocessing and re-use of polymer materials from manufactured objects that have reached the end of their operating life. Within this framework, formal professional agreements have been put in place at global level under the...

2021 Amsterdam : EFFECT OF CHLORINATED WATER ON THE FATIGUE CRACK GROWTH RESISTANCE OF POLYETHYLENE COMPOUNDS WITH RECYCLATE CONTENT FOR PIPE APPLICATIONS

Author(s) : Paul J. Freudenthaler, Joerg Fischer, Mathias Eder, Reinhold W. Lang

For controlled water disinfection, typically chlorine is used and preliminary studies demonstrate its aging and crack growth acceleration effects on polyolefin pipe materials [1, 2]. Although the use of recycled plastics is not prohibited in some ISO standards for polyolefin piping systems [3–5], only small amounts...

2021 Amsterdam : EFFECT OF INSUFFICIENT HOMOGENIZATION DURING THE EXTRUSION OF POLYETHYLENE PIPES ON BUTT FUSION JOINT INTEGRITY

Author(s) : Mike Troughton, Amir Khamsehnezhad, Changyi Yu

When butt fusion welding polyethylene (PE) pipes in the field, it is often specified that the pipes must undergo fusibility testing in all combinations of suppliers, diameters and thicknesses before being fused in production. This is a very onerous and expensive task, but must be carried out to ensure that the PE...

2021 Amsterdam : EVALUATION OF MECHANICAL PROPERTIES AND LONG- TERM DURABILITY OF AGED POLYETHYLENE PIPES FOR GAS DISTRIBUTION

Author(s) : Shuhei Nishida, Shintaro Iwasaki, Hidefumi Yamanaka, Takahiro Kasatani

Polyethylene pipelines have been used for natural gas service applications for over 40 years in Japan. It is thought that they will continue to be used widely for many years. Therefore, it is important to confirm the conditions of the existing pipelines being used for the long term. In this study, polyethylene pipes...

2021 Amsterdam : EXPERIMENTAL DETERMINATION OF THE EFFECTS OF LIQUID HYDROCARBONS ON THE LONG-TERM CREEP RUPTURE PROPERTIES OF PRESSURE PIPE GRADE UNPLASTICIZED POLYAMIDE-12

Author(s) : James F. Mason, Akshay Ponda, Hermann van Laak, Buc Slay

The effects of liquid hydrocarbons on long term strength of pipe grade thermoplastic resins is an important consideration when designing pressure pipe for use in the oil and gas industry. There is an extensive body of work going back several decades descri bing these effects for pipe grade polyethylenes, and all...

2021 Amsterdam : FINDING THE RIGHT PIPE TEST FOR POLYETHYLENE WITH RAISED RESISTANCE TO SLOW CRACK GROWTH

Author(s) : Ernst van der Stok

For PE 100-RC, two tests are still under development for pipes: the point load test (PLT) and the accelerated notch pipe test (aNPT). The PLT was developed by a project group consisting of manufacturers and end users. The PLT determines the resistance to point loads as they can occur in practice. An earlier study...

2021 Amsterdam : FINITE ELEMENT METHOD (FEM) USED TO SIMULATE THE STRESS/STRAIN OF THE POINT LOAD TEST (PLT) IN A BROADER STUDY TO SUPPORT THE FUTURE ISO TEST STANDARD

Author(s) : S. Nestelberger, J. Cheng

The Point Load Test (PLT) [‎ 1, ‎ 2] was designed to simulate the SCG (slow crack growth) failure initiated by a rock pressing into the exterior wall of a polymer pipe. Today’s PE materials sustain long PLT testing times, due to its high SCG resistance design. Consequently, an accelerated “PLT+” with the support of...

2021 Amsterdam : FIRST USE OF PE100-HT CONDUITS FOR ADVANCING THE CONTAINMENT OF UNDERGROUND HIGH VOLTAGE CABLES

Author(s) : Dr. Holger Brüning, Serge Hascoët, Yann Delanne, Didier Nozahic, Jawdat Mansour, José Santana

RTE operates, maintains and develops the French electricity network, including the High and very High Voltage cable lines. Their network is the largest in Europe and includes over 6400 km of underground HV links operated in 2018. The company is modernizing and developing its network by investing 1.5 billion euros per...

2021 Amsterdam : FLOWABLE FILL FOR PLASTIC PIPE

Author(s) : Amster Howard

Flowable fill is used for many applications, but mainly for pipe trench embedment and backfill. There are three ways that using flowable fill can be kind to the environment. Because flowable fill is self-leveling and has a strength greater than the native soil, the trench cross section can be minimized. This means...

2021 Amsterdam : FROM MULTILAYER LAMINATES TO INDUSTRIAL PIPE APPLICATIONS – A GUIDELINE

Author(s) : Gerald Pinter, Johannes Wiener, Florian Arbeiter, Abhishek Tiwari, Otmar Kolednik

For pipe applications, catastrophic failure due to crack growth has to be prevented by all means. Techniques to develop new and even tougher pipe materials are explored in this contribution. The aim is to create a multi-layer architecture, that exhibits high toughness as well as damage tolerance towards sharp notches....

2021 Amsterdam : HIGH THICKNESS AND LARGE DIAMETER PIPES MANUFACTURING WITH INNOVATIVE EXTRA LOW SAG PE100 IN MIDDLE EAST AND INDIA

Author(s) : Prashant Nikhade, Farraj Tashman

In the Middle East and India, PE pipes have expanded their applications in a big way for water supply, industrial effluents, corrosive chemical transportation, slurry transportation, city gas distribution networks and agriculture irrigation purposes over ductile iron, cast iron and other conventional pipes. PE...

2021 Amsterdam : HYDROGEN TRANSPORT IN POLYMER PIPES FOR NATURAL GAS DISTRIBUTION – TEN YEARS OF EXPERIENCE

Author(s) : Stephan Kneck, Henrik Iskov

It has become ever clearer that the resources of natural gas are an energy source, which will be less important in the future due to limitations in use of natural reserves. In order to prepare for the future the gas industry is looking at the alternative fuel gases, one such fuel gas is hydrogen. In order to prepare...

Members of the Association

BOREALISBOROUGEFormosa Plastics CorporationINEOS O&PIRPCKazanorgsintez PJSCKorea Petrochemical IND. Co., LTD (KPIC)LyondellBasellPetroChina Dushanzi Petrochemical CompanyPRIME POLYMERSABICSCG Chemicals & Thai PolyethyleneSinopecTASNEE
Webinar : Benefits of PE100+ Material and their use in Trenchless TechnologyWebinar : Benefits of PE100+ Material and their use in Trenchless Technology

On march 10th, was held the PE 100+ ASSOCIATION first webinar. The webinar was a great success and attracted a large audience. 

TOP