INTRODUCTION
Whenever a project, such as a chemical plant expansion, requires vessels and tanks, the specifying engineer's first thought is generally of metals. However, on a major chlor-alkali plant expansion project overseas, the metals that will stand up to the aggressive service, e.g. Titanium and Nickel 200, are very costly. In this plant, nearly half of the new equipment and piping was fabricated of non-metallic materials; predominantly fiber reinforced plastic (FRP) and dual laminates. This paper will give those unfamiliar with FRP pointers that will enable them to have a successful project using FRP, and to avoid expensive adders after the placement of orders for FRP equipment.
In a capital expansion project, whether it is for a new grass roots facility or for expansion of an existing facility, budget constraints dictate and sometimes limit the scope of the project. In recent years, besides technical expertise, specifying engineers have increasingly been called upon to consider ways to add value to the project, especially if the owner of the project is a client. What this means is to be able to accomplish a given scope with the least budget, without sacrificing quality or reducing the equipment design life. Many times, this requires engineers to consider other alternatives that have merit and not to limit themselves only to things they have done in the past.
Except for engineers who work for an FRP fabricator, engineers working for engineering and construction (E & C) companies, or operating companies such as refineries and chemical plants are probably more familiar with equipment constructed out of metals. The properties of metals are well known, and the design codes for metallic equipment go back a long way. When the corrosiveness of the service requires alloys higher than stainless steel, such as the high nickel content Monels, Hastelloys, Nickel 200 or Titanium, using FRP and dual laminate equipment is a very cost effective way to add new equipment, thus enabling the plant to accomplish the desired increase in capacity. Dual laminate equipment is used when the service is such that FRP is not sufficient, and a thermoplastic liner such as polypropylene (PP) or perfluoroalkoxy (PFA) has to be bonded to the FRP. The largest percentage of FRP and dual laminate equipment in a given facility are found in the chemical process industry, where chemicals such as chlorine and chlor-alkali products, strong acids, and strong bases are present.
This paper describes how to successfully transition from metals to FRP, using as a case history the equipment specified and bought for a chlor-alkali plant outside the U.S. The author?s previous experience was with metallic equipment for refineries. To develop the mindset for successful transition from metals to FRP, the engineer must dispel the myth that FRP does not last as long as metallic equipment. Properly specified and designed FRP and dual laminate equipment at chemical plants has held up for 20 years or more if well maintained, and these are in services other than water. If there are questions about whether a particular service is suitable for FRP or dual laminate, all the resin producers in the U.S. publish chemical resistance guides, provide technical support and consultation, and publish technical bulletins documenting successful case histories for different services.
