Controlling Hydrocarbon Emissions from Tank Vessel Loading (1987) / Chapter Skim
Currently Skimming:
4 Safety Concerns
4 Safety Concerns
Pages 93-107
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 93... ...
Human error is the major contributing factor to the presence of practically all ignition sources, except for lightning. Static buildup can, for example, be minimized by loading tanks at velocities consistent with accepted industry guidelines (International Chamber of Shipping et al., 1986)
|
From page 94... ...
For accidents during marine transfer of hydrocarbon fuels, the details of each accident scenario will depend on several factors, including: 0 type of delivery or receiving vessel, such as inland barge, ocean barge, or self-propelled tankship; O type and quantity of liquid cargo being transferred, for example, crude oil, gasoline, liquefied natural gas, or liquefied petroleum gas; 0 presence, if any, and types of vapor control and recovery systems used, such as adsorption, absorption, incineration, vapor balance, refrigeration, and inerting, or any combination; · location of the initial event, for example, above deck, below deck, in transfer lines, or in shore facilities; 0 operations underway, such as ballasting or loading; · presence or absence of adequate, well-maintained and tested automatic detection, alarm, and hazard control equipment; and · presence or absence of properly trained operating and response personnel. HISTORICAL ACCIDENT DATA Historical accident data are a valuable tool for determining potential failure modes and future accident scenarios.
|
From page 95... ...
Ten accidents of known origin involved human error as the major contributing factor. Eight of the accidents were directly attributable to personnel disregarding proper safety precautions and regulations, improper securing or rigging, and carelessness.
|
From page 97... ...
As far as could be determined, only one accident occurred in the United States involving a vapor control and recovery system during the period from 1980 to September 1986. This accident occurred at 21:30 on November 1, 1983, when the tank barges Hollywood 1015 and Rollywood 1016 exploded, burned, and sank while transferring acrylonitrile at the barge dock of the Sohio Chemical Company, Vistron Green Lake, Texas (U.S.
|
From page 98... ...
Detonation arrestors installed in vapor lines to stop detonation waves can fail to prevent fires, especially if the lines have bends in them. (In at least one case, a detonation wave burst every right-angle bend in a vapor line, passing through several detonation arrestors.)
|
From page 99... ...
Ignition in a long duct results in an accelerating wavefront and possibly a detonation. The effectiveness of commercially available detonation arrestors in stopping the fast, propagating flames of all potential fuel vapors is questionable.
|
From page 100... ...
The blowing or pigging of lines has also been cited as a major cause of tank failure in Europe. A vapor flow rate that exceeds the venting capacity of the line can lead to a sharp increase in pressure and line or tank rupture.
|
From page 101... ...
TECHNOLOGIES TO REDUCE THE RISK OF FIRE AND EXPLOSION Hydrocarbon vapor control at marine terminals will require careful design and risk analysis of the design to identify weaknesses in the system. Vapors being returned from a tankship or tank barge may frequently be in the explosive range (about 1-10 percent hydrocarbon in oxygen, with variations depending on hydrocarbon type, moisture, and other factors)
|
From page 102... ...
Detonation arrestors differ significantly from flame arrestors, however, in their rugged construction, which permits them to remain effective when the flame front is accompanied by the extreme pressure front that results from a fully developed detonation traveling through the pipe. Common end-of-line flame arrestors are totally ineffective in handling such fast-moving flame fronts and should be used only at openings into the system, to prevent flames from entering.
|
From page 103... ...
Additionally, a detonation arrestor should be located near the dock vapor connection and on the tank vessel at its vapor flange. Since very high pressures are associated with a detonation flame front, a rupture disk should be installed downstream near the detonation arrestor, oriented to allow the pressure front and flame to blow into a safe area should a detonation occur.
|
From page 104... ...
Another desirable alternative, especially in instances where the vessel operator has little control over the procedure used in the shore facility, is to install a shipboard pressure control system to allow the ship to control the cargo tank pressure independent from the shore facility.
|
From page 105... ...
Because of the limited number of vapor control and recovery systems used today and the relative short history of their use, both in the United States and Europe, there are not enough historical data to quantify the potential increase or decrease in risks associated with their use. Furthermore, the risks of accidents involving these systems are highly dependent on such factors as the geographic location of the marine terminal, the size of the exposed population, the value of the terminal and adjacent property that might be affected in case of an accident, the frequency with which the system is operated at the site, and the preventive and protective measures deployed at the site.
|
From page 106... ...
Secondary Impacts The increased cost of operating marine transfer terminals and vessels due to the regulation of vapor emissions may induce firms to leave the shipping business completely, or to transfer their business to unregulated terminals, if available. The increased costs may also displace some water shipping to other modes of transport that are less safe, as outlined below.
|
From page 107... ...
Data indicate that regulatory strategy analysts should include an estimate of the displacement of water transport into less safe transportation modes. Reduced hydrocarbon emissions at marine transfer facilities may be attained at the expense of more fires and explosions during railroad, truck, or pipeline transport.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.