Research Projects

Project at a Glance

Project Status: complete

Report Published January 1982:

Title: Study of visible emissions from ships with steam boilers

Principal Investigator / Author(s): Wyss, Walter A.

Contractor: Acurex Corporation

Contract Number: A9-121-30

Research Program Area: Emissions Monitoring & Control

Topic Areas: Mobile Sources & Fuels


Visible emissions from any source are restricted by California law from exceeding specified opacity standards as cited in the California Health and Safety Code, unless exempted. Vessels with steam boilers operating in coastal and inland waterways are granted specific exemptions in Section 41704 of the Code. Unlimited exemptions are applicable to steam boiler operations during emergency boiler shutdowns for safety reasons, safety and operational tests required by government agencies, and maneuvering required to avoid hazards. In addition, operations necessary to light off a cold boiler and to dry wet or green refractory materials are exempted until January 1, 1984, as long as they do not generate visible emissions which exceed Ringelmann 2 for 15 minutes or more in any hour. Prior to the enactment of the exemptions, emissions generated as a result of these latter two operations were permitted to exceed Ringelmann 2 for only three min/hr.

The bill which amended the Health and Safety Code to allow for the exemptions (SB 2198) also provided that a study be conducted in cooperation with local air pollution control districts and the maritime industry to determine if vessels using steam boilers can be brought into compliance with existing visible emissions standards by January 1, 1984. The objectives of this study were to survey ship operations relevant to the visible emission exemption conditions noted above, to investigate possible modifications to equipment and procedures which will reduce visible emissions, and to develop recommendations for a compliance schedule to reduce such emissions. The study was to consider the age and physical condition of shipping vessels, safety and operational requirements, and technological feasibility. The following sections of this document describe the findings of this study and present documentation and recommendations relative to the visible emission exemptions.
In order to meet the objectives of this study, the following tasks were performed:

* Normal and exempted operating modes were surveyed to identify the sources and periods of excess emissions
* The extent, frequency, duration, causes and quantitative impact of emissions were characterized
* Modifications to equipment and operating procedures to reduce visible emissions were investigated
* Regulatory recommendations are suggested

Study efforts were primarily focused upon vessels using steam boilers since these vessels are granted the exemptions; however, particulate emissions from both steam- and motor-powered vessels during normal modes of operation were quantified.

In addition to this introductory section, this report is subdivided into five sections followed by the appendixes. A discussion of background information is contained in Section 2 including brief reviews of California port activities, vessel traffic, shipboard combustion and visible emission regulations. Section 3 presents a review of both normal and exempted modes of operation and describes the reasons why steam boiler visible emissions are generated. Section 4 describes the methodology and results produced in an effort to establish the quantitative extent of particulate matter emitted from vessels while in California ports. Visible emission control options for steam boilers are identified and evaluated in Section 5. Regulatory recommendations and a discussion of future trends in the maritime industry follow in Section 6.


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