At present, high-pressure reinforced thermoplastic pipes in the world can be divided into two categories. One category aims to improve the ability to resist internal pressure. It is usually a three-layer structure, with various thermoplastics in the inner and outer layers and reinforcing materials (various fibers or metals) in the middle layer. It is usually called "Reinforced Thermoplastic Pipes (RTP)" internationally. The other category requires not only improved resistance to internal pressure, but also improved resistance to external pressure. It is usually a multi-layer structure (more than 5 layers), in addition to various thermoplastic layers, there are layers for resisting internal pressure, resisting external pressure and realizing other functions. It is usually called "Flexible Pipe (FP)" internationally.

Introduction

After half a century of continuous and rapid development, the global plastic pipe industry has reached a huge scale of about 16 million tons per year. In order to further expand the market field of plastic pipes and develop high-tech products, China and foreign countries have been working hard to explore and develop composite thermoplastic pipes in recent years. The purpose is to innovate pipelines with better performance by combining other materials.

There are many varieties of composite thermoplastic pipes, among which the most important goal is to achieve "reinforcement". Because the outstanding disadvantage of thermoplastics is low strength and stiffness. For example, the design stress of PE100, the highest grade HDPE pipe material, is only 8MPa (for comparison: the design stress of reinforcing fine steel wire is about 1000MPa). Therefore, the internal and external pressures that unreinforced thermoplastic pipes can withstand are limited (generally the internal pressure does not exceed 1.6MPa), and a lot of materials are consumed when the diameter is large.

There are many different types of reinforced thermoplastic pipes. The main goal of one category is to achieve the ability to withstand high pressure through reinforcement; the main goal of another category is to reduce the consumption of thermoplastics through reinforcement and to be able to manufacture larger diameters. This article will focus on high-pressure reinforced thermoplastic pipes.

The earliest promotion of the development of high-pressure reinforced thermoplastic pipes was the oil and gas industry. The oil and gas industry is a large user of pipelines. In the past, most of them used various steel pipes, and the most prominent problem was corrosion. With the development of industry and the advancement of technology, there is an urgent need to break through the limitations of traditional pipelines and seek new pipelines with better technical and economic performance. Interestingly, the first to be developed and put into practical use was the flexible pipe used in offshore oil and gas development (1967). Since the flexible pipe can not only ensure high strength (resistance to internal pressure, external pressure, fatigue and impact), but also corrosion resistance, light weight, flexibility, and can be supplied in very long coils, it has a very obvious competitive advantage in the offshore mining environment. At present, this high-tech and high-value flexible pipe has been widely used (including in China's offshore oil fields), and relevant standards and specifications have been issued earlier (such as API 17J, 17K, 17B of the American Petroleum Organization API; international standard ISO 13628, etc.). Driven by the success of the flexible pipe, the reinforced thermoplastic pipe RTP, which is suitable for use on land and shallow waters and has a relatively simple structure, has developed (1998). In recent years, many countries have developed and produced many varieties of RTP. Unlike flexible pipes, which are almost all reinforced with steel, RTP uses a wide variety of reinforcement materials (aramid fiber, polyester fiber, steel wire, steel belt, etc.).

Although the main market for high-pressure reinforced thermoplastic pipes is still in the oil and gas industry, they have also been successfully applied in many other application fields, such as long-distance natural gas transmission pipelines, submarine water pipelines, and high-pressure pipelines in mines.

After years of vigorous development, China's plastic pipe industry has reached a huge scale of 3.32 million tons per year, completing the initial stage of creation and expansion, and entering a new era of transformation from a plastic pipe power to a plastic pipe power. In the face of increasingly fierce competition, only by opening up new markets through technological innovation can a new situation be opened up in the future. Therefore, we have been advising China's plastic pipe industry (especially leading companies) not to limit themselves to traditional market areas and pay attention to new development opportunities. The development of high-pressure reinforced thermoplastic pipes is one of the new opportunities that deserves attention.

Technical Data Compilation

The newly developed reinforced thermoplastic pipe RTP in recent years has unique and significant advantages: it can withstand very high working pressure, is very corrosion-resistant, and maintains flexibility similar to HDPE pipe. It can be supplied in coils of hundreds or even thousands of meters. At present, it has been promoted and applied in the fields of oil and gas extraction, various high-pressure transmission pipelines, etc., and the development prospects are predicted to be very broad.

RTP is usually a three-layer structure. The inner layer is a thermoplastic such as HDPE, the middle layer is a reinforcement layer composed of aramid fiber, steel wire or other high-strength materials, and the outer layer is a thermoplastic protective layer such as HDPE. The basic production process is to extrude the inner layer of thermoplastic pipe first, then interlace the reinforcing belt composed of aramid fiber and the like, and finally extrude the outer protective layer of thermoplastic. RTP also includes "Flexible Pipe (FP)" which can not only withstand high internal pressure, but also high external pressure, and has a multi-layer structure.

At present, the development and production of RTP in China has just started, and the flexible pipes used in deep-sea oil extraction and other applications still rely on imports. This is a new market opportunity that is worth striving for.

In order to promote the development of reinforced thermoplastic pipes in China and promote the independent innovation and development of China's plastic pipe industry, Mr. Zhang Yuchuan of the Beijing Plastics Industry Association edited this "Reinforced Thermoplastic Pipe RTP Technical Data Compilation 2010" based on many years of research.

This compilation consists of four parts.

The first part is the important literature on reinforced thermoplastic pipes published in recent years in the world;

Including 9 documents such as reports published in the International Plastic Pipe Conferences from 1998 to 2008, it comprehensively introduces the process of technological innovation of reinforced thermoplastic pipes in the world, and systematically discusses the theoretical analysis and practical experience of reinforced thermoplastic pipe structure design, material selection, manufacturing process, connection technology and application methods. Absorbing and utilizing these achievements can enable China's development and innovation to start from a high level.

The second part is an introduction to the mainstream products of reinforced thermoplastic pipes in the world;

This part collects information on the main companies and products that produce reinforced thermoplastic pipes in the world. Including various high-pressure reinforced thermoplastic pipes RTP and multi-layer flexible pipes for offshore oil and gas production using different reinforcement materials such as aramid fiber, glass fiber, steel belt. The design and performance of these successful products can serve as an important reference for our development.

The third part has an analysis of the market demand for reinforced thermoplastic pipes in China and suggestions on key issues in development and innovation.

The three published papers provide analytical opinions and reference suggestions on the problems and disputes encountered in the development of reinforced thermoplastic pipes in China. I hope it can help Chinese companies broaden their thinking and avoid setbacks in technological innovation.

The fourth part is about international standards and specifications for reinforced thermoplastic pipes;

This part has three standard specifications: ISO/TS-18226 of the International Organization for Standardization, DVGW VP642 of the German Water and Gas Association, and API17J of the American Petroleum Organization. The ISO standard and DVGW specification for reinforced thermoplastic pipes for high-pressure gas transmission released in recent years are the major achievements of a large number of international experiments and studies. Mastering these standards and specifications can help our reinforced thermoplastic pipes enter the market outside China as soon as possible. The first to formulate a series of specifications in the field of reinforced thermoplastic pipes was API, and the complete and detailed API 17J is a recognized basic standard.

Mr. Zhang Yuchuan of the Beijing Plastics Industry Association has long cooperated with China Pipeline Business Network. With the participation and help of many leading enterprises and institutions, in recent years, he has been organizing the search, collection, translation, introduction and dissemination of the latest development information, scientific and technological achievements and market experience of the international plastic pipe industry, paying special attention to international conference materials that reflect the highest international level. This compilation only selects some of the main materials of RTP. Enterprises that research and develop reinforced thermoplastic pipes are welcome to contact and communicate with the editor and China Pipeline Business Network. The editor and China Pipeline Business Network are willing to do their best to provide good services. We believe that the development of reinforced thermoplastic pipe RTP will open up a broader market for China's plastic pipe industry and bring a more prosperous prospect.

We would like to express our deep gratitude to the companies and experts who provided information, participated in translation, and supported and helped in the publication of this compilation.

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