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' Recovery of weighed amounts of halogeaated hydrocarbons -has been within 95-100 percent. MAR a B74 ijausitl UlC COlllCUli l/l IIJC HLKUlUCt lO a J<J ml Vo'' metric flask. It is necessary to blow air through inlet of the absorber to remove liquid below the friitM glass. Wash absorber several times with disAifed Source-- water and make t volume. The sample can now t* Not commercially available. Contributed by: Dow Chem ical Company. Approximate cost--$200.00. , * i Construction Details analyzed or transferred, to separate sample bottles fo, later analysis. Calibration Instructions | Figure 1 is a drawing of the fritted glass absorber used in ' conjunction with the combustion apparatus. The apparatus was assembled as shown in Figure 2. To insure correct rates of air flow the flow meter should be periodically checked against a wet test meter. - Malntenpncn instructions it | Operating Instructions 1. Prior to sampling, the furnace must be heated to about 900C. Approximately twenty to thirty minutes is required for a warm-up period. 2. Connect the furnace to a sample point by means of a Saran line joined with rubber and glass joint connec tions. 3. Pipette 25 ml of trapping solution (1 percent sodium carbonate, 1 percent sodium formate solution) into the absorber. Turn the pump on and adjust the air flow rate (1.0 1pm proven efficient). The length of time of sampling will depend on the estimated concen- 1. Proper lubrication of pump should be maintained. ! 2. Fresh dessicant should be maintained in the drm tube.--- *: 3. Flow meter must be kept clean to insure accurate readings. 4. Temperature of combustion furnace should be ch-ct^j - periodically. ? Bibliography 't ; ! Determination of Chloride: A Modification of the Volhard Method. Caldwell and Moyer. Ind, Eng. Chetn. Anal. Ed. 7; 38 (1935). .i -i * HALOGENATED HYDROCARBON ANALYZER 'i Uses . The halogcnated hydrocarbon analyzer is used to record continuously in the parts per million range the concentration' of halogenated hydrocarbon gases in the air throughout a plant . .. Operating Principle A continuous sample of air is drawn from each of twelve plant areas through Saran tubing and is metered through twelve rotameters located on the flout panel. The air is then passed through a furnace containing twelve quartz tubes operating at approximately 1000G The halogen in the presence of water vapor in the air is converted to the halogen add. From here the add is mixed with water through absorber tubes, the water being metered to each absorber by means of a rotating orifice operating under a constant head tank. Two 6-record Foxboro Dynalog recorders are used to measure the resulting conductivity. . Physical Description Weight-- Height-- Width-- Depth-- Measuring Unit Approx: 500 pounds 8 feet, 10 inches 2 feet 1 foot, 10 inches Panel Approx. 150 pounds 7V4 feet 2 feet 1 foot The sampling and measuring unit is designed for perma nent installation but the panel containing the two Dynalog rec"orders may be m--o!u>n! te'PdWlfrWe--motely with respect to 1 the -*--.r v* :v^- Ucc Q34919 This instrument has been used successfully over a period of time on methyl chloride, ethyl chloride, methyl bromide, carbon tetrachloride, vinyl chloride, and vinylidiene chloride. Its range is limited by the purity of water available, range of recorder, and CO, or other interfering gases present in air deemed as "zero." ....... 'Range: Range limitations of this instrument have not fully been investigated. Air rates, water rate, recorder range and cell constants all may be varied, giving this instrument abundant flexibility. Extreme ranges have not been required in the Dow applications. Toxic limits have somewhat determined ranges f instruments now in use; i.en vinyl chloride 0*1000 ppm; vinylidiene chloride 0>S00 ppm; ethyl chloride 0-1000 ppm; carbon tetrachloride 0-300 ppm. Experimental units have been operated at both lower and higher ranges with excellent results and further investigation is in progress. The accuracy of all instruments now in operation is within 10 percent of analyzed gas samples. Source-- ' Not commercially available. Contributed by: Dow Chem ical Company. * FlgiM* 3 -- Boer Viow ef Anolyxor Shewing Mtaiwtas Unit onct Ktiwdir renal (From Teg el Photo). A. Mooturing Unit--(1) Semple Line Input* (12 In thb Cow), 14* Pipe/ (2) Fvmecef (3) Quart* Tubot Petting Through C attraction Details . Following are the essential components used in the con struction f this instrument: 12 points 6 points # Req'd. # Req'd. 1 1 Heavy Duty Pyrometer 1 1 Heavy Duty Furnace 1 1 Heavy Duty tap changing transformer 1 1 Vacuum pump 1 1 Bodine motor 1 1 Constant level water chamber 24 12 Needle valves 12 6 Rotameters 4 4 Fittings (Crouse-Hinds) 1 1 Switch box Tygon tubing 4 Terminal strips 6 Elbows 45 brass Vi inch 6 Couplings brass Vi inch 12 6 Quartz tubes 1 1 Steam condenser or ion exchange tower 2 1 Foxboro Dynalog conductivity recorder Operating and Maintenance Instruction* 1. Check pyrometer at top of front panel on measuring unit. This may vary from 1000C to 1090C. At no time should this temperature vary from these limits. a. If in excess of 1090'C, adjust taps located on trans former. An adjustment decreasing the "fine**' control 1 or 2 divisions should be sufficient. b. If less than 1000C, check furnace fuse. (Located on right facing rear of panel, in fuse beat.) Check thermocouple, check taps on furnace and increase "fine" adjustment 1 or 2 divisions. 2. Check rotameters!. Balls should ride with their bottoms . adjacent to top of marking tabs. Adjustments are made by needle valves on top header. Any oscillations may be damped by adjusting needle valves on water leg locate ; inside panel. Check to insure constriction is not ^ great so as not to allow the allotted quantity of water ^ * reach the cell. This may be done by removing rotating ' arm and filling leg in question, replacing the arm an; ^ checking to see whether or not the water level decreases Rotameters should be cleaned periodically when the cn; of sample tube is subjected to a dusty atmosphere ! when dust or oil film accumulation is noticed in tube. 3. Remove rotating aim from water distributor and chl 'L flow. - 4. Check vacuum pump for oil level in trap on vacuum side : of pump. This oil is used for lubrication. No flui* : should be present In the trap on pressure side of pump. 5. Check absorption tubes and rubber tubing.. 6. Check conductivity cells for bubble formation on plates. ; If present, partially remove cell allowing inrushing air to '! remove bubbles. | 7. Clean pens on recorder and replace ink pads when * needed. j 8. When instrument has been shut down and is again to be put into operation, allow the water system to run 10 ; minutes before starting pump so the water legs will be v fuIL Also check the ball in the vacuum release valve to ^ insure free operation. -7 9. In case of pump failure and a replacement pump is not * available immediately, voltage on furnace should be reduced by changing taps on transformer to lowest possible value to avoid operating the furnace at higher - than rated capacity. * Calibration instructions 'i ,* f Calibration is accomplished by contaminating a metered f air stream with a known amount of material. This stream is sampled, analyzed by the instrument and at the same time checked against a standard. 7 I I CARBON DIOXIDE INDICATORS * * s Carbon dioxide indicators can be used to determine the' concentration of CO, present in the atmosphere of a closed space or compartment Other uses include analysis of Sue gases and combustion testing. Op rating Prindpto A measured volume of air or flue gas under test is drawn into the absorption column by means of an aspirator bulb. Carbon dioxide in the sample is absorbed by a solution of potassium hydroxide contained in the absorption and manom eter columns. The resulting reduction of gas pressure (the scale having been previously set to zero at the top of the liquid column) is an indication of the percentage of CO, present in the sample. Percent CO, is read directly from the scale; upon the various ranges. The model shown in Figure I. for example, weighs 1 pound and is 2Vi by 114 by 9 inches high. All models are built of acrylic plastic construction employ ing stainless steel for all metallic parts in contact with the fluid. The instruments are portable in design and provided with carrying cases and other accessories as needed to operate in the field. Figure 2 is an enlarged drawing of the # 800-5 (0 to 5 percent) Carbon Dioxide Indicator showing the various components. UCC Performancm Data Q34Q21 Various ranges and accuracy limits are available as fol lows. # 800-5 Carbon Dioxide Indicator, range 0-5 pef' cent CO minor divisions 0.10 percent accuracy at full scale lYIttrt `k 10/*t :*+' *-v. f. *.' .. j **' T.'i ;V* .*>. '... HALOGENATED HYDROCARBON ANALYZER . Raymond M. Donahue - _ _'/*V ^ V;;\\V '*v-. v.. ;,,k V*'*o;,- ^Midland, Michigan r' i-.----v./* : yi * *' : *V /-fT1 Tv H . ............. .......... .. ._ ,,,, .`.t ` ,\. ' $ TM V f . ., v( , -T. 7, ; * ** \.r *#** v-' v ,*;x The Company has for many years beer* particularity concerned about the health and well-being of the%mployees who ' *i;ir`r/: ... *- * A' , are directly involved .in the manufacture of various "chemical - a'. products. /V/-. . ... 4.. `.iV-ifx* i St * j* >* v-\ -'-i*/'**'' -f'-v - LT: In the manufacture of a product In which a halogenated hydro .,, "J 4a . .* + t carbon is Involved, .analyzing the ambient air within the plant- " * . "7 7* buildings has been one method of safeguarding the employee X. ~ against an exposure that-might not otherwise bedetected until upper threshold limit values were exceeded. ft* *1. ' The Halogenated Hydrocarbon Analyzer was developed by for the purpose of recording the concentration of halogenated hydrocarbons in air in the parts per million range. It is usually a 6-point or 12-point Instrument. :. The operatlon'of this Instrument can be described as follows: A continuous.sample of air Is drawn from specified locations through Saran tubing and Is metered through rotameters located on the front panel. .This air is then passed through quartz tubes In a furnace at a controlled temperature, depending upon the particular compound being looked for. While passing through the furnace, the halogen in the.presence of water vapor in the air Is converted to the halogen acid such as hydrogen bromide or hydrogen chloride. From here the acid gas is scrubbed by deionized water In passing the absorber tubes. The water Is metered to each absorber tube by means of a -rotating orifice operating under a constant head tank. The-conductivity of the resulting solution Is directly pro portional to the amount of a halogenated compound present ucc 034922 In the sample gas. This conductivity measurement Is made by a Foxboro multi-record recorder which measores and prints out twelve sample points In 72 seconds.. The air and water flows are so adjusted that the chart readings may be Interpreted directly In parts per million of a halogenated hydrocarbon In a1rv In this particular analy zer shown here, the range Is 0-500 ppm of methyl.bromide In air and IS set to alarm when any one. point exceeds 50 ppm. This analyzer Is a 12-pointer with a .'rimge of 0-500^| ppm of methyl chloride and alarm point set t:'100 ppm. When the alarm system Is activated, a horn Is energized as well-as a flashing beacon In the analyzer area. At the same time a .. similar light is In operation in other areas in the'building Including the office. This signal Informs personnel In all. areas of the building that a leak has occurred, and specific location of the leak Is determined by the recorder printout. This general, or full area alarm system. Is particularly helpful to minimum size operating crews at night at which time a leak In a remote storage area could be detected before the atmosphere accumulated over the threshold limit values. In addition to the alarm set point on parts per million con centration, there Is. also a device which detects furnace temperature failure. This alarm Is necessary because if the furnace temperature falls off, then-conversion Is not com plete and operating personnel would be unaware of an acci dental leak. This furnace Is a vertical tube type with the sample inlet on top, and the outlet below feeds directly to the absorber where the gas is Immediately scrubbed. Thus, with the use of a vertical tube furnace, there are no traps in the outlet which night accumlate residual concentrations of the halogen acids. -2- Pure water 1$ essential to the proper operation of the analyzer. Steajn Is .condensed, cboled, and th*eq the con densate run through- an Ion-exchange bed and filtered to 25 microns before entering the constant level tank. . The water distributor receives a constant head of water from a float tank and contains an orifice on the end of a rotat ing arm driven by.a 60 rpm synchronous motor. .As the arm revolves, the water stream Is divided into either six or!-.', twelve portions by a segmental cup and delivered to the ';/ water traps,. The "U" traps prevent sucking of air into the absorbers through the water lines to the absorbers. Anti surge valves are one-eighth needle, valves and serve to re duce pulsing of the water flow Into the absorbers. The suction regulator is a ball type. . .*' V . * ,, r The glass absorbers and conductivity cells are connected to the nickel air and water header by means of bored out rubber stoppers. The air samples which have passed through the furnace enter Into the top connection on .the absorbers. Metered streams of water from the rotating orifice pass into, the side arms at the top of the absorber assemblies. The air and water pass with parallel flow at high velocity through*the three millimeter*capillary tubes where most of the HBR and HC1 Is scrubbed out of the air. The air and water then separate, the air passing through the upper glass outlet and-lnto the nickel header, and the water passing down through the conductivity cell, and thenceHnto the header. The absorbers have been dipped Into a 10% solution of hydrogen flourlde to facilitate wetting and to even flow along the walls of the capillary. This instrument does not meet requirements for areas classified either as semi-hazardous or hazardous. The measurement unit must be located In an area where hazardous conditions never exist--even in an emergency. It is -3- ucc Impossible to make the Instrument safety shutting off the power, as the furnace will stay hot for a considerable * aa period of time. Installations have'been made where the measurement unit was located in a standard area and over 250 feet away from the sample points and recorders; the latter being installed in another direction In the operating panel area. . ... : ' ' This analyzer requires a normal amountsof instrument main- tenance.. The water flow to the absorbers'and cells must remain constant If the Instrument Is1 to maintain its. call- ` brated range. This, then. Is checked frequently. Air sample flow rates, furnace temperature stability, alarm systems, and recorder operations are also checked periodic ally- ,t The Section makes a calibration check of each analyzer every six months. Preventive main tenance schedule calls for quartz tube and connecting rubber tubing replacement on six-month intervals also. This quartz a.nd rubber replacement insures a high instrument measurement sensitivity. Sample lines are checked for leaks every month and repaired or replaced immediately if necessary. The Halogenated Hydrocarbon Analyzer is obviously not specific for any one halogenated compound, so it can show the.concentra tion of a particular.compound only if it is the only one . present which is contributing to the conductivity. Chlorinated as well as bromlnated materials as stated earlier have been . analyzed with this Instrument. The range can be changed by: 1. Changing the conductance range of the recorder. 2. Changing the water rate to the cells. '3. Changing the air flow rate. -4- Furnace temperature control Is more critical on some compounds than others. There is a several hundred degree spread be tween the efficient* conversion of some halogenated hydrocarbon compounds than others. There Is a noticeable fact evident to our Lab people who have developed, installed, and maintained these analyzers from their beginning, and that is: When there Is a changeover of supervision In the plants where these analyzers are located, then there Is a new,, vigorous approach to safety, and the analyzer Is soon equipped with an addition al horn or flasher. . Over a period of years and after several management1changes, one can easily visualize a Halogenated Hydrocarbon Analyzer with alarms and redundancy on the alarm . . rendundancy. / The process operator who has lived through these changes and additions to the alarm system has beep known to' take'steps In his own way to reduce the sensitivity and Intensity of the system. This particular method Is called the fresh- air purge. Plant .supervision has. learned that the best method to reduce the number of alarms is to have a tight process--that is no pump seal leaks, valve packing gland leaks, etc. At present there are nine analyzers In the Plant measuring through 102 sample points. In addition, there are two more in use In Plants, and one analyzer Is operating In Europe. . There are several variations of this basic Instrument In use at present In the Plant. Example: SOg Is monitored in the and * Power Houses by using 12-point analyzers without the furnace; that is, the sample of the ambient air is Introduced directly to the absorber. POClj has- also been analyzed this way. In another, it.is-used solely as a process monitor where process cooling water is analyzed for a,.methylene chloride leak. Clean air is swept over an . enclosed temperature controlled flowing sample, and that air is the 1nfluent sample to the Halogenated Hydrocarbon Analyzer. 4 The object In this case Is. to drive out. the methylene chloride. If any, from the water sample by heatfng, and to sweep the air sample to the analyzer where It Is pyrolyzed, scrubbed, .... and measured. This* has been used as a clear water sewer :... monitor. . .* - : ;. At one plant where methyl chloride in air Is. analyzed, the . measurements of each sample point were fed to a computer where time weighted averages of each sample-point in the plant area were recorded. Future plans are belng'considered in which- * * .?" *, , -- 1, the computer Input from every sampleijjolnt will result in analytical feedback to the .* , Plant and the Group i . v' * - * * * "r,. i.T*, " \ , * .1, G- * ucc 034927