September 5, 2012

CEMS Prove Ideal for Complex Marine Monitoring Applications


The need to monitor fuel burning efficiency and emissions is common to many industries and nowhere is this more relevant than in marine applications. For one South Korean shipbuilding and marine engineering company, Daewoo Shipbuilding & Marine Engineering (DSME), continuous emission monitoring solution (CEMS) equipment from Emerson Process Management, Rosemount Analytical has allowed it to improve the operational performance of its floating production, storage and offloading (FPSO) vessels, meet regulatory requirements and perform real-time emissions monitoring of its exhaust gases.

With rising energy costs, maritime companies work hard to monitor the flow of fuel in ships, FPSOs and other sea-faring vessels. Equally important is assuring the efficiency of the burning process. Thus, the installation of a CEMS allows the operator to monitor the emissions of the fuels being burned by the vessels. This information helps determine the need for scrubbers to reduce CO2, NOx and SO2, which may be required to meet international maritime standards.

The FPSO CEMS provided is a system which is custom-engineered for the analysis of samples taken from four different streams. As the samples from these streams are laden with moisture, due consideration has to be taken to ensure all sample stream components are kept in the same gaseous phase. Hence, all sample streams are heated from the sample take-off points and also kept hot to prevent unwanted condensates in the AISI 904L sample tubings. A sample conditioning system is used to properly condition the sample to suit each separate analysis by different analyzers. The sample system is also designed to ensure quick response to the change of samples taken from each sample point. The sample conditioning system and analyzers are housed in an IP65 weatherproof CEMS enclosure made of 316SS material. A PLC (programmable logic controller) is also used to execute certain functions within the sample conditioning systems. An on-demand request to the PLC will activate the pneumatic blowback, typical of CEMS that handle particulate content which may clog the filter at the sample take-off point. This is also implemented within the design of the sample conditioning system to clean the filter at the sample take-off point. The electrical components of this whole system are required to meet the requirements of ATEX Zone 1, Gas Group IIA.

While other technologies may be used in on-shore plants, the space limitations in a tightly knitted FPSO mean that the use of CEMS is more appropriate. In most cases CEMS allows the user to be able to have the dry basis measurement, not on a wet basis. In addition, the analyzers used for CEMS do not require air conditioning as other technologies do since they are designed to be suitable for up to 50oC ambient temperatures. Air conditioning takes space and generates heat and the need to meet ATEX certification means a more expensive type of air-conditioning system is used. The simplicity and reliability of this self-contained CEMS makes it an ideal choice for these demanding marine applications where the FPSO is deployed.

May 15, 2012

Using CEMS for Emissions Abatement in Cogeneration Facilities

Cogeneration facilities are considered to be among the most modern, energy-efficient producing facilities because of their superior environmental performance. Their purpose is to generate and distribute steam which can be used for heating, domestic hot water heating, humidification, sterilization of water and distilling water. During the cogeneration process, steam passes through a double automatic controlled extraction pressure and condensing steam turbine generator, and as a result, the electricity it produces becomes a beneficial byproduct. The combination of these results in a thermal efficiency greater than that of any plant built strictly for power generation.

Cogeneration greatly reduces the environmental impact; in addition, these facilities rely heavily on advanced technologies and continuous emissions monitoring systems (CEMS) to ensure strict regulatory compliance with State and Federal environmental agencies such as the EPA.

Cogeneration facilities can utilize multiple and varied fuel sources. These fuels can include natural gas, oil, coal, wood, various forms of bio-solids, and even tires. Combined cycle cogeneration facilities are becoming popular in meeting increasing energy demands. A typical facility will include a gas turbine, heat recovery steam generator (HRSG) and a steam turbine. The size of cogeneration facilities can vary greatly from small hospitals to large petrochemical complexes.

Since cogeneration facilities vary so significantly in size, fuel burned, pollution abatement equipment installed, and geographic location, the continuous emissions monitoring (CEM) requirements placed upon a given facility will also vary from plant to plant. The primary federal regulations defining CEM requirements are found in 40 CFR 60 and 40 CFR 75. The latter is also known as the Clean Air Act Amendments of 1990. However, state and local agencies do have the ability to impose additional and/or stricter requirements for the monitoring and control of pollutants. The federal regulations, based upon the fuel(s) utilized and the generating capacity of the facility, may require the monitoring of sulfur dioxide (SO2), oxides of nitrogen (NOx), opacity, a diluents [carbon dioxide (CO2) or oxygen (O2) and stack flow. In addition to the above requirements, state and local agencies may also call for the monitoring of carbon monoxide (CO) and, in those plants where SCR or SNCR is utilized for NOx reduction, may require monitoring of ammonia (NH3) as well.

Flameproof gas analyzers provide single and multicomponent gas analysis. Coupled with a remote-mounted sample conditioning system and flow distribution/system controller, these CEMS become truly modular emissions monitoring systems. This configuration allows sample extraction and conditioning anywhere along the sampling train, reducing costs for heated sample lines, equipment racks and instrument shelters. To check out a wide range of other possible configurations click HERE.

The growing significance of cogeneration combined with the unique requirements of each plant make CEMS an ideal solution since they can be designed specifically for each cogeneration plant while providing a field-proven analysis technology that is both highly accurate and cost-effective.