Scrubber system performance

Typical scrubber system performance is given in Table I. It was derived from test results, and it shows two cases—one representing a power... 

No magnesium sulfate was added to the system for run MG-3. The objective of this run was to evaluate the system performance with decreasing Mg2+ concentration. The mass balance indicated that the total Mg2 concentration should drift down to below 500 ppm. During the run, the total Mg2+ concentration decreased from 1000 ppm to about 625 ppm toward its end. A leak was discovered at the scrubber bleed/quench recirculation pump inlet which introduced air into the process stream and therefore caused high oxidation. The high oxidation, as confirmed by solids analysis results in Table 3, was reflected by increases of the sulfate-to-sulfite ratio to above 2.5. After the air leak problem was corrected, the sulfate-to-sulfite ratio decreased, but the test average was 2.4. 

All performance criteria were readily achieved with the exception of particulate emissions. This latter limit subsequently was met by placing 1 micron filter elements within the wet scrubber system and processing high-solids content waste at a reduced feed rate. The average mustard destruction efficiency (>99.999987%) was calculated using the lower detection limit of the CSEM mustard analyzer, as no agent was detected by manual stack surveys. 

In the absence of a detectable blank, the relationship of the logarithm of peak area to the logarithm of the mass of injected DMS should be linear over at least two orders of magnitude. However, blanks may occur as a consequence of decreasing system performance after prolonged use (e.g., decreased sulphur scrubber efficiency, decreased surface silylation) or because of DMS traces in the seawater samples used for calibration. In this case, significant deviations from linearity are observed at low analyte levels. Therefore, the blank contribution, Wb, to the total amount of injected DMS must be taken into account ... 

Scrubber Ttfpes and Performance The diversity of particulate scrubber designs is so great as to defy any detailed and selhconsistent system of classification based on configuration or principle of operation. However, it is convenient to cliaracterize scrubbers loosely according to prominent constructional features, even though the modes of operation of different devices in a group may vary widely. 

Aqueous, alkaline fuel cells, as used by NASA for supplemental power in spacecraft, are intolerant to C02 in the oxidant. The strongly alkaline electrolyte acts as an efficient scrubber for any C02, even down to the ppm level, but the resultant carbonate alters the performance unacceptably. This behavior was recognized as early as the mid 1960 s as a way to control space cabin C02 levels and recover and recycle the chemically bound oxygen. While these devices had been built and operated at bench scale before 1970, the first comprehensive analysis of their electrochemistry was put forth in a series of papers in 1974 [27]. The system comprises a bipolar array of fuel cells through whose cathode chamber COz-containing air is passed. The electrolyte, aqueous Cs2C03, is immobilized in a thin (0.25 0.75 mm) membrane. The electrodes are nickel-based fuel cell electrodes, designed to be hydrophobic with PTFE. 

Equations 9-2 and 9-3 apply to rupture discs discharging directly to the atmosphere. For rupture discs discharging into a relief system (which might include knockout drums, scrubbers, or flares), the rupture disc is considered a flow restriction, and the flow through the entire pipe system must be considered. The calculation is performed identically to regular pipe flow (see chapter 4). The calculation to determine the rupture disc area is iterative for this case. Isaacs5 recommended assuming that the rupture disc is equivalent to 50 pipe diameters in the calculation. 

As the raw material of rendering plants produces very odoriferous substances, air cleaning systems are usual. Five such air cleaners in normal performance were measured olfactometrically. The olfactometric efficiency of biofilters proved to be better than that of chemical scrubbers. A large difference between the relative odour concentration in the cleaned air and asserted limit values, based on older olfactometric methods confirm the necessity of a standardisation of olfactometric measurement methods. 

Sulfur dioxide in the sample causes a negative interference of approximately 1 mole of ozone per mole of sulfur dioxide, because it reduces the iodine formed by ozone back to potassium iodide. When sulfur dioxide concentrations do not exceed those of the oxidants, a method commonly used to correct for its interference is to add the amount of sulfur dioxide determined by an independent method to the total detector response. A second method is to remove the sulfur dioxide from the sample stream with solid or liquid chromium trioxide scrubbers. Because the data on the performance or these sulfur dioxide scrubbers are inadequate, the performance for each oxidant system must be established experimentally. 

Several experiments were run to test the robustness of the system. Overall the performance was considered effective and the conclusions about the conversion of a chemical scrubber to a bioflter were positive. 

A preliminary-level economic evaluation (13) performed by EPRI (Electric Power Research Institute) and TVA (Tennessee Valley Authority) indicates that a combination of electrostatic precipitators (or bag house), ammonia-based SCR system, and wet lime/limestone FGD scrubber range between 20% to 185% cheaper than wet process for complete control of particulates, N0X and S02 The lower percentage is for the second type and higher percentage for the first type of process. Therefore, the second type of process appears to be more promising and will be the subject of further discussion in this paper. 

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