API TR 939-D:2003 pdf download

API TR 939-D:2003 pdf download.Stress Corrosion Cracking of Carbon Steel in Fuel Grade Ethanol: Review and Survey.
Over the past 10 years, approximately a dozen incidences of failures produced by SCC of carIxn steel in fuel grade ethanol were identified, with several more possible hut unconfirmed cases. These included plate steels and roof springs used in tanks, along with associated piping and vessels. Cracks produced by SCC are tight and oxide tIlled, making them hard to identify by visual examination and conventional magnetic particle testing. Wet fluorescent magnetic particle testing appears to have the sensitivity to find these cracks. Remedial actions have included weld repairs, replacements and: use of internal coatings/linings to tanks on the bottom. lower sides and roof areas and fixtures. Coatings used in this service must have chemical resistance to fuel grade ethanol.
A gaps analysis was conducted that identified the following items that need to he addressed to better minimize service problems associated with SCC in fuel grade ethanol. These gaps include needs for better definition of the environmental variables that promote and/or control SCC in fuel grade ethanol that are not known at this time, and the role of metallurgical and mechanical variables which has not been quantitatively addressed. There is also a need to study the issue of whether it is possible to have SCC in fuel grade ethanol that meets the current industry standards for fuel grade ethanol. Additionally, the relationship between laboratory tests (U-bends and slow strain rate tests) and service experience has not been well established.
2 Introduction
2.1 SCOPE
The American Petroleum Institute (API), Refining Committee, Subcommittee on Corrosion and Materials (SCCM) contracted the development of this white paper document on SCC in fuel grade ethanol to InterCorr International, Inc. (Houston, Texas). A broad cross-section of companies have a high interest in this problem has actively participated in this effort to review and survey the industry experience. This group includes users, ethanol producers, research organizations and API and RFA representatives. This was the first part of a multi-part plan to address the needs of the industry regarding this SCC problem. The initial focus was that the white paper needed to be developed expeditiously to provide a concise and accurate review of the currently available information on SCC in fuel grade ethanol, documentation of the experience from companies involved in fuel ethanol supply, mid-stream distribution and refinery use, and an initial assessment of the potential economic impact of this problem to the refining industry.
The SCCM plan developed was for the white paper to precede a follow-on effort involving more in depth one-on-one surveying, applied research and testing to specifically investigate SCC in fuel grade ethanol as it applies to refinery operations. This proposal covers only the white paper development phase of the API sponsored effort. However, it does try to identify gaps in information and technology that might be addressed in the subsequent work.
2.2 TECHNICAL BASIS
The technical basis of the white paper originates from the information presented and identified at the workshop held on January 14 — 15, 2003. This meeting was well attended by representatives from a broad cross-section of companies that have a high interest in this problem. Based on the API Request for Proposal (dated January 30, 2003), it was of utmost importance to develop this white paper in a short time frame so that follow-on actions could be more completely formulated and activities initiated in short order to handle industry needs for this information.
2.3 TECHNICAL APPROACH
Since (as indicated above) the project period for the proposed white paper development was limited, the main portion of this efthrt involved an endeavor to gather the data identified and/or discussed in the API workshop on SCC in fuel grade ethanol (January 2003) and to search and capture additional information from readily available sources as time allowed.