HC1 emissions

Acid regeneration plants have storage tanks for spent and regenerated acid and these tanks are potential sources of HC1 emissions. Emission estimates for uncontrolled and controlled storage tanks at acid regeneration facilities are 0.0126 and 0.008 tpy per 1000 gallons of storage capacity, respectively. 

Figure 12. A series of time-resolved spectra of HC1 emission taken after initiation of a chain reaction by laser photolysis of Cl2 in the presence of C2H6. At the earliest time delay shown here HC1 is highly excited, and relaxes by collisional deexcitation at later times. Reproduced with permission from Ref. 86.

Figure 14. Spectra of the products of IRMPD of CH2CFC1 taken under conditions of higher decomposition yield than in Figure 13, brought about by addition of 1.6Torr Ar to 40mTorr of the precursor. At the time of observation, 45

Establish maximum chlorine feed rates while maintaining HC1 emissions below permit levels,... 

The incineration of waste containing PVC has been a source of much discussion and comment, particularly related to the dioxin and HC1 emissions (66,106, 282, 341). PVC was also targeted in the EU incineration directive (297). 

There are few air pollutants emitted in the NSC system, especially low are HC1 emissions. 

Fig. 4.3.1 Effect of pH on the total light emission of phialidin (A), and the temperature stability profiles of phialidin (minute open circles) and aequorin (solid line) (B). In A, each buffer contained 0.1 M CaCl2 plus 0.1 M Tris, glycine or sodium acetate, the pH being adjusted with NaOH or HC1. In B, the photoprotein samples in 10 mM Tris-EDTA buffer solution, pH 8.0, were maintained at a test temperature for 10 min, and immediately cooled in an ice water bath. Then total luminescence activity was measured by injecting 1ml of 0.1 M CaCl2/Tris-HCl, pH 7.0, to 10 pd of the test solution. From Levine and Ward (1982), with permission from Elsevier.

When a photoprotein solution (1.3 ml) was shaken with ethanol (0.7 ml) containing one drop of concentrated HC1 and then the mixture was extracted twice with 2 ml each of ethyl acetate, about 75% of the chromophore was extracted into the ethyl acetate extract. The chromophore isolated showed an absorption peak at 398 nm in neutral methanol (Fig. 10.2.5). The isolated chromophore was practically non-fluorescent, like the native photoprotein. However, the acidification of a methanolic solution with HC1 resulted in a sharpening and two-fold increase of the 398 nm absorption peak, accompanied by the appearance of fluorescence. In aqueous 0.1 M HC1, two fluorescence emission peaks (595 nm and 650 nm) were found, together with a corresponding excitation peak (400 nm). Treatment of the 398 nm absorbing chromophore with 0.1 M NaOH resulted in a rapid loss of the 398 nm absorption peak. Dithionite did not affect the 398 peak, suggesting that the chromophore does not contain Fe3+. 

J cm-2 x 0.3 = 1.5 J cm-2 or 6 x 10-6 einstein cm 2 (1 einstein associated with the 488 nm emission has an energy of 2.45 x10 Joule mole- ). On the other hand, about 7 x 10 mole of HC1 are evolved by each square centimeter of a 20 ym C-PVC film transformed into carbon. The quantum yield of HC1 evolved can then be calculated from the following ratio ... 

The Subpart O standards4 for hazardous waste incinerators set performance standards that limit the quantity of gaseous emissions an incinerator may release. Specifically, the regulations set limits on the emission of organics, HC1, and PM. The following section outlines the requirements for each of these substances. 

BIFs are required to comply with strict air emission standards to ensure adequate protection of human health and the environment. These standards are divided into four contaminant categories organics, PM, metals, and HC1 and chlorine (Cl2). For each category or type of emission, the regulations establish compliance methods and alternatives. Each is addressed in Table 23.3. 

The combustors affected by this rule detoxify or recover energy from hazardous waste and include incinerators, cement kilns, lightweight aggregate kilns, boilers and process heaters, and hydrochloric acid production furnaces. U.S. EPA estimates that 145 facilities operate 265 devices that burn hazardous waste. These technology-based standards reduce emissions of hazardous pollutants, including lead, mercury, arsenic, dioxin and furans, and HC1 and chlorine gas. In addition, emissions of PM are also reduced. 

Flue gas containing HC1 goes to a venturi preconcentrator and an absorption column. There, the generated acid contains approximately 18% HC1 by weight. Emissions from acid regeneration plants range from about 1 to more than 10 tpy from existing facilities with and without pollution control devices (controlled and uncontrolled facilities). 

Acid recovery systems are used to recover the free acid in the WPL. They are not employed in larger facilities because they recover only 2-4% free HC1 from the spent acid, but leave the FeCl2 in the solution that must be processed or disposed of separately. These acid recovery systems are generally closed-loop processes that do not emit HC1. In their survey, U.S. EPA compiled data from different types of pickling operations and their estimated emissions.5 This information is reproduced in Table 28.11. 

A National Emission Standard for Hazardous Air Pollutants (NESHAP) for new and existing hydrochloric acid process steel pickling lines and HC1 regeneration plants pursuant to Section 112 of the Clean Air Act as amended in November 1990 has been proposed (62 FR 49051, September 18,1997). The purpose of this rulemaking is to reduce emissions of HC1 by about 8360 megagrams per year. 

In addition to the gaseous emissions from the combustion of fuel, gaseous emissions are also produced by chemical production, for example, SO, from sulfuric acid production, NO from nitric acid production, HC1 from chlorination reactions, and so on. 

The CTC-HC1 FDA Working Standard gives a yellow fluorescence under longwave ultraviolet (UV) light (375 nm) (35). The excitation (324 and 357 nm) and emission (443 nm) spectra of this standard dissolved in 0.05N NaOH (11.4 mg/50... 

Fig. 17 (a) Chemical structure of polythiophene poly((3,3"-di[(S)-5-amino-5-carbonyl-3-oxapen-tyl]-[2,2 5 2"])-5-,5"-terthiophenylene hydrochloride), PONT, (b) Emission spectra of 6.5 pM PONT—HC1 (on a chain basis) in 25 mM HC1 (black spectrum), 25 mM HC1 with 5.0 pM of native bovine insulin (blue spectrum), 25 mM HC1 with 5.0 pM fibrillar bovine insulin (red spectrum). The emission spectra were recorded with excitation at 400 nm [31]... 

The film reacted with adipoyl chloride followed by coupling with 7-hydroxycoumarin was subjected to methanolysis at 1 N HC1 and 60°C. The regenerated coumarin was assayed at pH 10 by fluorescence spectroscopy at an excitation wavelength of 329 nm and an emission wavelength of 455 nm. A Hitachi MPF-4 Fluorescence Spectrophotometer was used for all fluorescence measurements. 

The launch of the space shuttle and other vehicles such as the Titan launch vehicles results in emissions directly into the troposphere and the stratosophere. Exhaust emissions include A1203 (30% by weight), CO (24%), HC1 (21%), H20 (10%), N2 (9%), C02 (4%), and H2 (2%) (Danilin, 1993). 

The major focus on the effects of exhaust emissions has been on the HC1 component and its role in ozone depletion and on the A1203 particles, which could provide a surface for the heterogeneous conversion of HC1 to active forms of chlorine. It has been proposed that if the HC1 were converted to photochemically active forms relatively rapidly, a mini ozone hole could form in the flight path of the vehicle (Aftergood, 1991 McPeters et al., 1991 Karol et al., 1992). 

Jerome V.V. Kasper Dr G.C. Pimentel of the University of California, Berkeley, reported laser emission in the infrared energized by the reaction H +CI2 ->HC1 +C1. They fill a laser tube with a mixture containing 1 volume of CI2 and 2 volumes of H2, which is then exposed to the flash from a Xe-filled quartz flash tube. The resulting laser emission is centered near 3.8 microns in the IR... 

The results reported by Carrasco et al. (1998) revealed that nearly all studied metal emissions, measured at the exit of a cement kiln stack, were significantly higher when a blend of 80 wt% coal + 20 wt% TDF was combusted instead of pure coal. Especially notable are increased emissions in Cr, Mn, Cu, Zn, and Pb (Table 9). The exception to this trend is Hg, which exhibited a 30% reduction in its emission rate when the coal + TDF mixture was burned. The data further document reductions in NO and organic compound emissions, including PAHs, where the most drastic decrease was observed for dioxins and furans. On the other hand, emissions of CO, S02, and HC1 increased considerably with the addition of TDF (Table 9). The total particulate emissions from combustion of the blend were only slightly greater than those from pure coal. Carrasco et al. (1998) used their data to model atmospheric dispersion of the emitted contaminants in the vicinity of the... 

Emission from Cl(32Py2) has not been detected in flow systems40 although this excited atom has recently been observed in absorption following the vacuum ultraviolet flash photolysis of a number of chlorides, including HC1.2B The over-all rate for the reaction... 

---