Inlet Air Filtration Research Articles

Advanced gas turbine packaging

Latest achievements, new procedures and modern methods on the gas turbine packaging and the integration of a gas turbine in a plant are discussed. The goal is an optimum gas turbine package arrangement considering performance, reliability and commercial conditions. The focus is to explain latest technologies and recent methods to obtain the lowest ‘total cost of ownership’ for a gas turbine package. Critical areas related to the gas turbine packaging such as the inlet air filter system, the fuel system, the heat recovery system, the control system, monitoring methods, the lubrication oil system and others are explained. A case study is also presented.

Lessons learned from fire in air supply ducts

In 2012, loss of air flow caused activation of interlocks to shut off steam and electrical heat inputs to an air heating system that was part of a drying/milling operation. Shortly thereafter, upstream filters and air ducts ignited causing more than US$500K in damage and business interruption. Investigations concluded that the interlocks functioned as designed on loss‐of‐airflow but were not sufficient to prevent overheating the inlet air filters (including HEPA filters) by the residual heat in the air heaters. The two main lessons learned from this fire incident apply to a broad range of operations in the chemical process industries (CPI): Mundane unit operations such as air filters that have combustible components must be evaluated as thoroughly as the rest of the chemical process. Designers and PHA leaders must recognize the potential of thermal inertia of heaters (and coolers) to heat (or cool) a stagnant volume of fluid when flow is interrupted. Gas streams are particularly susceptible due to the low heat capacity relative to the heat capacity of a metallic heat exchanger. Interlocking the supplies (to steam and electrical heaters in this incident) is often necessary but may not be sufficient. Other lessons “relearned” include the importance of learning from a previous near miss, the importance of limiting escalation aspects of this fire, and the importance of preventative maintenance. © 2014 American Institute of Chemical Engineers Process Saf Prog, 2014

Technology Review of Modern Gas Turbine Inlet Filtration Systems

An inlet air filtration system is essential for the successful operation of a gas turbine. The filtration system protects the gas turbine from harmful debris in the ambient air, which can lead to issues such as FOD, erosion, fouling, and corrosion. These issues if not addressed will result in a shorter operational life and reduced performance of the gas turbine. Modern day filtration systems are comprised of multiple filtration stages. Each stage is selected based on the local operating environment and the performance goals for the gas turbine. Selection of these systems can be a challenging task. This paper provides a review of the considerations for selecting an inlet filtration system by covering (1) the characteristics of filters and filter systems, (2) a review of the many types of filters, (3) a detailed look at the different environments where the gas turbine can operate, (4) a process for evaluating the site where the gas turbine will be or is installed, and (5) a method to compare various filter system options with life cycle cost analysis.

Five Steps to Evaluate a Gas Turbine Inlet Air Filtration System

This article discusses five steps for evaluating a gas turbine inlet air filtration system. The first step to evaluate an inlet filtration system is to study the operating environment. It is important to understand what must be removed from the air by the filtration system before evaluating the existing system. Once the operating environment is defined, the existing filtration system can be evaluated. Third step is the maintenance, which is an important part of any system. It ensures that the system will stay in an operable condition and perform as required. There are several tasks which, if performed consistently and correctly, can ensure that the filtration system operates properly. Fourth step is the upgrades, which should be considered if the operator finds deficiencies in the current filtration system. The fifth step is completing a lifecycle cost analysis. This analysis quantifies the cost and performance of a system in monetary terms to obtain a lifetime cost of the system. The lifetime costs between two different system options can be directly compared.

Utility Perspective of Selecting Air Filter for Simple-Cycle, Heavy-Duty Combustion Turbines

The combustion turbines evaluated for this study range in size (nominal) from 80 MW to 100 MW and operate at a compression ratio between 10 and 14. Under these conditions the compressor ingests about 500,000 to 725,000 cubic feet of air per minute for its rated output. With this volume of air, even low concentrations of contaminants can result in a significant total amount of contaminants entering the unit, which may cause compressor erosion, fouling, and foreign object damage in the compressor section and cooling air passage blockage, locking of turbine blade roots, and hot corrosion or sulfidation in the turbine section. Adequate protection against the above-mentioned degradation or damage due to poor air quality may be obtained by using properly designed air filters. An inadequate filter system or total lack of one results in a reduction in power and efficiency over the life of the unit and may significantly decrease the intervals between maintenance and thereby increase the cost of maintenance. Consideration should be given to adding an air inlet filter when or after the combustion turbine without air filter is overhauled to reduce future maintenance costs. This study investigates the need for an inlet air filtration system for simple-cycle, heavy-duty combustion turbines from a cost/benefit and operation standpoint. Options for inlet air filters include a self-cleaning pulse type filter, a surface loading cartridge filter without pulse feature, and a three-stage depth loading type media type filter. Benefits are determined by estimates of improvements in performance and effects on the combustion turbine’s longevity and maintenance.

World’s First Full STIG™ LM5000 Installed at Simpson Paper Company

In early 1988, Simpson Paper Company installed the world’s first GE LM5000 cogeneration plant with full high and low pressure steam injection. The full STIG LM5000 achieves a dramatic power increase (from 32.5 MW to 49.5 MW) and remarkable improvements in efficiency from 36 to 43 percent, while reducing NOx emissions from 225 to less than 25 ppmv before further reduction with SCR. The plant, installed at Ripon, CA, features: (1) 130,000 lb/hr (59,000 kg/h) of steam injection at three locations on the gas turbine; (2) the first-time use of SCR with the STIG LM5000 resulting in an ultimate NOx emission rate of 6-13 ppmv; (3) a unique feedwater heat exchanger arrangement to reduce boiler stack temperature to 250°F (121°C); and (4) an innovative submicron inlet air filtration system to minimize the need for compressor washing. The details of cycle selection, design, installation, performance, and economic benefits of this first full STIG installation provide a useful insight into the potential of a flexible new technology.

New ventilated isolation cage.

A multifunction lid has been developed for a commercially available transparent animal cage which permits feeding, watering, viewing, long-term holding, and local transport of laboratory rodents on experiment while isolating the surrounding environment. The cage is airtight except for its inlet and exhaust high-efficiency particulate air filters, and it is completely steam-sterilizable. Opening of the cage's feed and water ports causes an inrush of high velocity air which prevents back-migration of aerosols and permits feeding and watering while eliminating need for chemical vapor decontamination. Ventilation system design permits the holding in adjacent cages of animals infected with different organisms without danger of cross-contamination; leaves the animal room odor-free; reduces required bedding changes to twice a month or less, and provides investigators with capability to control precisely individual cage ventilation rates. Forty-eight cages can be conveniently placed on a standard NIH "shoebox" cage rack (60 inches wide x 28 inches deep x 74 inches high) fitted with a simple manifold exhaust system. The entire system is mobile, requiring only an electrical power outlet. Principal application of the caging system is in the area of preventing exposure of animal caretakers to pathogenic substances associated with the animal host, and in reducing handling of animals and their exposure to extraneous contamination.

New Ventilated Isolation Cage

A multifunction lid has been developed for a commercially available transparent animal cage which permits feeding, watering, viewing, long-term holding, and local transport of laboratory rodents on experiment while isolating the surrounding environment. The cage is airtight except for its inlet and exhaust high-efficiency particulate air filters, and it is completely steam-sterilizable. Opening of the cage's feed and water ports causes an inrush of high velocity air which prevents back-migration of aerosols and permits feeding and watering while eliminating need for chemical vapor decontamination. Ventilation system design permits the holding in adjacent cages of animals infected with different organisms without danger of cross-contamination; leaves the animal room odor-free; reduces required bedding changes to twice a month or less, and provides investigators with capability to control precisely individual cage ventilation rates. Forty-eight cages can be conveniently placed on a standard NIH "shoebox" cage rack (60 inches wide x 28 inches deep x 74 inches high) fitted with a simple manifold exhaust system. The entire system is mobile, requiring only an electrical power outlet. Principal application of the caging system is in the area of preventing exposure of animal caretakers to pathogenic substances associated with the animal host, and in reducing handling of animals and their exposure to extraneous contamination.