ATMOSPHERIC EMISSIONS FROM HYDROCHLORIC ACID MANUFACTURING PROCESSES r* •F'l U. S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE Public Health Service Consumer Protection and Environmental Health Service ------- ATMOSPHERIC EMISSIONS FROM HYDROCHLORIC ACID MANUFACTURING PROCESSES Cooperative Study Project Manufacturing Chemists' Association, Inc. and Public Health Service U.S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE Public Health Service Consumer Protection and Environmental Health Service National Air Pollution Control Administration Durham, North Carolina September 1969 For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 - Price 35 cents ------- The AP series of reports is issued by the National Air Pollution Control Admin- istration to report the results of scientific and engineering studies, and infor- mation of general interest in the field of air pollution. Information reported in this series includes coverage of NAPC A intramural activities and of cooperative studies conducted in conjunction with state and local agencies, research insti- tutes, and industrial organizations. Copies of AP reports may be obtained upon request, as supplies permit, from the Office of Technical Information and Publi- cations, National Air Pollution Control Administration, U.S. Department of Health, Education, and Welfare, 1033 Wade Avenue, Raleigh, North Carolina 27605. National Air Pollution Control Administration Publication No. AP-54 ii ------- FIGURES 1. Yearly production of 100 percent hydrochloric acid .... 2 2. Typical by-product hydrochloric acid process (chlorobenzene) 10 3. Synthesis chlorine-hydrogen process 14 4. Synthesis process hydrogen chloride burner 15 5. Cross-sectional view of Mannheim furnace 17 6. Mannheim hydrochloric acid manufacturing process flow diagram 18 7. Cross-sectional view of Laury furnace 21 8. Hydrogen chloride distillation system for reagent-quality acids 23 9. Falling film absorber with external piping and tails tower . . 27 10. Falling film absorber with integral gas piping and tails tower . 28 11. Typical adiabatic hydrochloric acid absorption unit flow diagram 29 A-l Impinger gas sampling train 36 A-2 Grab sample bottle 37 A-3 Burette for adding absorbing reagent 38 A-4 Mist sampling train 42 C-l Vapor pressure of hydrochloric acid at various concentrations 53 C-2 Specific gravity and density versus percent hydrogen chloride 53 C-3 Relationship of viscosities of hydrogen chloride and water . . 54 C-4 Heats of solution of hydrogen chloride in water 54 C-5 Vapor-liquid equilibra for hydrochloric acid 55 C-6 Boiling point of hydrochloric acid solution 56 C-7 Freezing point of aqueous hydrogen chloride 57 111 ------- TABLES 1. Production of hydrochloric acid by process type 1 2. Hydrochloric acid production in United States 6 3. Emissions from by-product hydrochloric acid manufacturing plants 12 4. Hydrogen chloride emissions from synthesis plants 16 5. Emissions from Mannheim plants 20 C-l Specific gravities of aqueous hydrochloric acid solutions ,,. . .52 iv ------- PREFACE To provide reliable information on the nature and quantity of emissions to the atmosphere from chemical manufacturing, the Public Health Service, United States Department of Health, Education, and Welfare, and the Manufacturing Chemists' Association, Inc., entered into an agreement October 29, 1962, to study emissions from selected chemical manufacturing processes and to publish information that would be helpful to air pollution control and planning agencies and to chemical industry management.* Direction of thes^ studies is vested in an MCA-PHS Steering Committee, presently constituted as follows: Representing PHS Representing MCA Stanley T. Cuffef Willard F. Bixbyt Robert L. Harris, Jr. Louis W. Roznoy Dario R. Monti Clifton R. Walbridge Raymond Smith Elmer P. Wheeler Information included in these reports describes the range of emissions during normal operating conditions and the performance of established methods and devices employed to limit and control such emissions. Interpretation of emission values in- terms of ground-level concentrations and assessment of potential effects produced by the emissions are both outside the scope of this program. *Reports in this series to date are Atmospheric Emissions from Sulfuric Acid Manufacturing Processes, Public Health Service Publication No. 999-AP-13; Atmospheric Emissions from Nitric Acid Manufacturing Processes, Public Health Service Publication No. 999-AP-27; and Atmospheric Emissions from Thermal-Process Phosphoric Acid Manufacture, National Air Pollution Control Administration Publication No. 48. These publications are available from the Manufacturing Chemists' Association, Washington, D.C., and the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402. f Principal representatives. ------- ACKNOWLEDGMENTS Sincere gratitude is extended by the project sponsors to the many individuals and companies who have contributed to this study. Special thanks are due the following companies, which participated in the stack sampling program. Detrex Chemical Industries. Diamond Shamrock Chemical Company. Olin Mathieson Chemical Corporation. PPG Industries, Inc. Tennessee Corporation. The following companies provided technical information and other assistance in the preparation of this report. Carbon Products Division, Union Carbide Corporation. Falls Industries Process Equipment Division of Carborundum. Haveg Industries, Inc. Samuel L. Bean of Allied Chemical Corporation, Industrial Chemicals Division, and Howard Wall, Jr., National Air Pollution Control Administration, were the investigators in the study and are the authors of this report. The sponsors acknowledge the contribution of the Allied Chemical Corporation in providing the services of Mr. Bean. VI ------- USE AND LIMITATIONS OF THIS REPORT This report is one of a series on atmospheric emissions from chemical manufacturing processes. It provides such information on the manufacture of hydrochloric acid. Basic characteristics of the industry, including growth rate, manufacturing processes, product uses, and the number of producing plants in the United States are discussed. Process descriptions are given for the chlorinated by-product process and the synthesis process, which employs the direct combustion of hydrogen in chlorine. Mannheim, Hargreaves, and several other processes are included for their historical interest, even though the number of plants that use them is decreasing rapidly. Process information includes the range of emissions of hydrogen chloride from hydrochloric acid manufacturing plants and the methods of limiting or controlling these emissions to the atmosphere. Although other contaminants such as chlorine, chlorinated organics, and other hydrocarbons emitted to the atmosphere from these plants are mentioned and in some cases discussed, they are not the primary concern of this report. Detailed descriptions of the sampling and analytical methods used in measuring such emissions are also included. The production of hydrochloric acid has been a basic industry in the United States for many years; manufacturing procedures have become well established. Plant design, throughput rates, and the use of special systems to reduce emissions are factors that influence atmospheric emissions. Emission data contained in this report were obtained from 18 percent of the present hydrochloric acid manufacturing locations. Most of the data are from the records of acid producers. The data include results of stack sampling programs conducted by the National Air Pollution Control Administration as part of the joint study. Although this report is a technical review prepared primarily for public officials concerned with the control of air pollution, it is expected that it will also be helpful to chemical plant management and its technical staff. This report should be reviewed at intervals to determine when revision is necessary to reflect prevailing conditions. Vll ------- CONTENTS SUMMARY 1 Manufacturing Processes 1 Hydrochloric Acid Production . 2 Typical Emissions 3 Control of Emissions 3 Emission Guidelines 3 GROWTH OF HYDROCHLORIC ACID MANUFACTURING INDUSTRY 5 Historical Background 5 Current Uses 5 HYDROCHLORIC ACID MANUFACTURING PROCESSES 9 By-Product Hydrogen Chloride 9 Typical Process Description—Chlorobenzene 10 Emissions 11 Control of Hydrogen Chloride Emissions 11 Synthesis Process 13 Introduction 13 Emissions 16 Control of Emissions 16 Mannheim Process . ,-, 16 Introduction 16 Emissions 19 Control of Emissions 19 Hargreaves Process , 19 Introduction 19 Emissions 19 Laury Process 21 Introduction 21 Emissions 21 ANHYDROUS HYDROGEN CHLORIDE 23 Introduction 23 Emissions 24 IX ------- REAGENT-GRADE HYDROCHLORIC ACID MANUFACTURE 25 Emissions 25 Air Blowing 25 Hydrogen Chloride Absorption Systems 26 Falling Film Absorber 26 Adiabatic Absorber 26 Emissions From Absorber Systems 26 Control of Emissions 29 DEFINITIONS 31 APPENDIX A: SAMPLING AND ANALYTICAL TECHNIQUES 34 Determination of Hydrogen Chloride and Chlorine in Stack Gas 34 Acid Mist Sampling 41 Determination of Sulfates and Sulfuric Acid 43 APPENDIX B: HYDROCHLORIC ACID MANUFACTURING ESTABLISHMENTS LOCATED IN UNITED STATES 45 APPENDIX C: PHYSICAL DATA- HYDROCHLORIC ACID 51 REFERENCES 5§ ------- ATMOSPHERIC EMISSIONS FROM HYDROCHLORIC ACID MANUFACTURING PROCESSES SUMMARY MANUFACTURING PROCESSES Approximately 80 percent of the hydrochloric acid in the United States is manufactured as a by-product of the chlorination of organic compounds. By-product hydrogen chloride is produced in the manufacture of chlorinated benzene, vinyl chloride, chlorinated methane, chlorinated ethylene, toluene diisocyanate, and other such compounds. The second most important source of hydrochloric acid is the synthesis process in which hydrogen is reacted with chlorine. This process produces a relatively pure hydrogen chloride, which may be converted to hydrochloric acid or recovered as anhydrous hydrogen chloride. Less than 10 percent of the hydrogen chloride manufactured in the United States is produced by a reaction of sulfuric acid on metal chlorides, the principal one of which is sodium chloride. Table 1 illustrates the decline in importance of the salt process and the increased importance of by-product hydrogen chloride sources. Table 1. PRODUCTION OF HYDROCHLORIC ACID BY PROCESS TYPE (percent of total)1 Year 1935 1947 1958 1961 1962 1966 1967 Salt reaction 86 53 13 10 9 9 8.5 Synthesis 14 4 18 13 14 7 7 By-product 43 69 77 77 84 84.5 Hydrogen chloride is often processed into hydrochloric acid in package plants that consist of a falling film absorber and a packed tower. If the unit is ------- used to make acid from a by-product process, the organic materials are usually removed from the hydrogen chloride by condensation or absorption before the hydrogen chloride is absorbed in water. If the organic content of the acid is objectionable, another kind of package plant, which consists of an adiabatic unit in which the acid is formed at its boiling point in a packed column, may be used. In this case, organic materials with low boiling points are not allowed to condense. The acid is then cooled and passed through a carbon bed to remove the final traces of organic material Regardless of the type of hydrogen chloride absorber used to form hydrochloric acid, the most efficient system, from an atmospheric emission viewpoint, is characterized by a final scrubber that removes any remaining trace of hydrogen chloride from the system. HYDROCHLORIC ACID PRODUCTION In 1965 a total of 1,318,122 tons of hydrochloric acid was produced in the United States.1 Based on the increase in production between 1945 and 1965, the growth rate is 40,000 tons per year, as shown in Figure 1. 1,300 1,200 — 1930 1935 1940 1949 19» 1955 I960 1965 1970 Figure 1. Yearly production of 100 percent hydrochloric acid. HYDROCHLORIC ACID EMISSIONS ------- TYPICAL EMISSIONS The atmospheric contaminants emitted from the manufacture of hydrochloric acid are hydrogen chloride, chlorine, chlorinated organic compounds, and other organic materials. The exact type and quantity of contaminants vary with the process and the type of tail gas control system used. The concentration of hydrogen chloride emitted to the atmosphere is usually less than 0.5 percent of the tail gas volume emitted to the atmosphere. The average tail gas volume emitted to the atmosphere from the plants reviewed for this report is 40 cubic feet per minute, with the rates ranging from 2 to 550 cubic feet per minute. On a combined basis, the tables herein show that 6 of the 26 plants reporting were emitting hydrogen chloride above the 0.5 percent level. One of the six plants was permanently shut down after testing. Another was in the process of installing a new scrubber to reduce emissions to the 0.5 percent level. Another dispersed its gases by diluting them with stack gases from a boiler. CONTROL OF EMISSIONS Emissions from hydrochloric acid plants are adversely affected by (1) high temperatures in the absorption system, (2) improper balance of absorption area and contact time, (3) faulty equipment, and (4) inadequate tail gas scrubbing systems. Emissions of hydrogen chloride or hydrochloric acid can also be caused by operational upsets. The most common method used to remove hydrogen chloride from tail gas is to scrub the gas with water. This method is inexpensive and effective. Alkaline scrubbing is sometimes used when other compounds that are not readily absorbed in water, such as chlorine or phosgene, are present. Emissions of organic and chlorinated organic compounds, which come from sources other than the direct manufacture of hydrogen chloride or hydrochloric acid, vary considerably and present a different problem in each case. Reduction of emissions of these compounds may requke a more efficient organic absorption system, a phosgene breaker, a benzol absorption system, or some other system especially suited to remove a particular emission. Efficiencies of these control systems often exceed 99 percent. In some cases, emissions to the atmosphere are prevented by utilizing a closed system for the entire organic and hydrogen chloride plant. EMISSION GUIDELINES Hydrogen chloride emissions to the atmosphere! usually total less than 0.5 percent of the tail gas volume. This is a relatively small quantity of hydrogen chloride because gas volumes for plants reporting range from 2 to 550 cubic feet per minute with an average of 40 cubic feet per minute. Adequate control equipment is available to prevent emissions of more than 0.5 percent hydrogen chloride, or about 0.5 pound per ton of acid produced. In the event of an emergency shutdown of a hydrochloric acid plant, the hydrogen chloride gas source should be shut down first. Liquid flow to absorption equipment should be maintained at a level sufficient to keep all Summary ------- tubes and/or packing wetted and thus prevent hydrogen chloride emissions to the atmosphere. Some weak acid will be made during this shutdown period, but it can usually be adjusted by producing somewhat highei-than-normal- strength material later. This technique of maintaining at all times more liquid flow than the amount required for surface wetting should also be used to prevent hydrogen chloride emissions during routine shutdowns and startups. HYDROCHLORIC ACID EMISSIONS ------- GROWTH OF HYDROCHLORIC ACID MANUFACTURING INDUSTRY HISTORICAL BACKGROUND Hydrochloric acid, which is also called muriatic acid, was first described by Valentius in the Fifteenth Century and was studied by such eminent chemists as Thenard, Cavendish, Priestly, and Gay-Lussac.2 The first large-scale production of hydrogen chloride began as a by-product in the LeBlanc soda ash process wherein salt and sulfuric acid are reacted to produce salt cake. Originally this hydrogen chloride gas was vented to the atmosphere; however, since this indiscriminate discharge killed vegetation, over a large area surrounding the manufacturing plants, legislation was soon introduced in England to prohibit it This restriction initiated the expedient of dissolving the hydrogen chloride in water, which forms hydrochloric acid. Soon uses were discovered for the acid, and subsequently plants were built for its manufacture as the primary product with salt cake as a by-product. Demand for salt cake was reduced as the Solvay process replaced the LeBlanc process for making soda ash. In the United States, the reaction of sulfuric acid and salt, an initial step in the LeBlanc process, was used to manufacture hydrochloric acid rather than soda ash as the prime product. The heating of salt and sulfuric acid to form hydrogen chloride gas is also the principal operation of the Laury and the Mannheim processes. The Hargreaves process, which involves reaction of salt and sulfur dioxide, is used in only two plants in the United States; and like the Mannheim process, it is costly and its use probably will be discontinued soon. As can be seen in Table 1, originally, most hydrochloric acid was produced from the reaction of salt and sulfuric acid. As the chemical industry grew, more acid was produced through by-product methods and more acid was produced by burning hydrogen in chlorine than was produced from the reaction of salt and sulfuric acid. At the present time, the by-product process is the largest source of acid; burning of hydrogen in chloririe (synthesis process), the second largest source; and salt sulfuric acid and other processes, the third largest source of acid. Table 2 and Figure 1 show the growth trends of this industry. CURRENT USES i Because a large portion of the total hydrochloric acid produced is derived from by-product operations, the locations of production do not always coincide with the areas of use. Shipping costs for acid are high because about 70 percent by weight of the usual commercial-strength acid is water. Unusual regional supply-and-demand situations result. In some localities a Mannheim furnace, which is usually costly to operate, can be run at a profit to produce acid for local needs. At other locations (along the east coast of the United States in particular) by-product acid is often in oversupply and is dumped into the ocean. Some manufacturers ship hydrogen chloride in its anhydrous liquid ------- form to reduce transportation costs and to enable them to compete in markets far from the source of production. Table 2. HYDROCHLORIC ACID PRODUCTION IN UNITED STATES1 Year 1933 1935 1937 1939 1941 1943 1945 1947 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 (preliminary) 1967 (preliminary) Tons HCI produced 100% basis 63,000- 87,000 122,000 140,000 228,000 342,000 408,000 442,558 484,000 618,784 693,541 683,742 771,241 740,604 838,249 911,430 917,081 848,487 955,914 970,167 910,967 1,052,116 1,079,443 1,228,068 1,368,122 1,505,000 1,597,000 Hydrochloric acid is used for pickling steel, for producing glucose from corn and other starches, making and purifying bone char, bleaching sugar, chlorinating chemical compounds, chlorinating rubber, activating petroleum wells, and processing food and drugs. Less well known uses include the manufacture of alkyl chloride used in making tetraethyl lead; preparation of chlorides from alcohols; preparation of pharmaceutical-grade chemicals such as adipic acid, citric acid, amine hydrochlorides, and aconitic acid; dehairing of skins in tanning; and production of silica gel Hydrochloric acid is also used as a catalyst in organic reactions. I Several recently built vinyl chloride plants both make and use hydrochloric HYDROCHLORIC ACID EMISSIONS ------- acid.3-4 Part of such a plant manufactures vinyl chloride with chlorine, wmcn yields the by-product hydrochloric acid. The other part of this plant manufactures vinyl chloride utilizing the by-product hydrogen chloride. Such a plant can be designed and operated so that no excess acid is produced. Growth of Industry ------- HYDROCHLORIC ACID MANUFACTURING PROCESSES BY-PRODUCT HYDROGEN CHLORIDE By-product hydrogen chloride, which results from the chlorination of organic compounds, constitutes the largest source of hydrochloric acid. Numerous reactions will form hydrogen chloride. Most of these reactions take place when chlorine is added to an organic compound. If a chlorinated hydrocarbon is hydrolized with water, hydrogen chloride is produced. An example of a process that generates hydrochloric acid as a by-product is the direct chlorination of benzene. The equation for the chlorination of benzene is: eerie *• ci2. - »• c6risci + HCI This reaction takes place in the presence of a chlorine carrier, such as ferric chloride.2 The yield is about 70 percent. In addition to the conversion of benzene to benzene monochloride, some benzene dichlorides are formed according to the reaction: C6H5C1 + C12 - > CetttClj + HCI Benzene dichloride concentration can be increased by allowing the monochloride to remain in the reactor for a longer period of time than required for its production. The ratio of paradichlorobenzene formed to orthodichlorobenzene is generally fixed, but trace additives can be used in the chlorine to vary this ratio. Chlorobenzenes are used as intermediates for synthesizing various organic compounds, solvents and preservatives for paints, moth balls, fumigants, germicides, and deodorants.2 Hydrogen chloride is formed also by regeneration in some chlorination processes. For example, the chlorination of benzene and subsequent hydrolysis to phenol occur according to the following reactions: 2HC1 + 03 - > 2C6HsCl + 2H20 H2O - > C6H5OH + HCI In such reactions, the chlorination and hydrolysis take place in separate steps and the acid is separated, purified, and sent back to the chlorination process. Other processes that produce hydrogen chloride include the chlorination of methane, the chlorination of paraffin, and the formation of intermediates for urethane foams. ------- TYPICAL PROCESS DESCRIPTION - CiSLOROBENZENE The raw materials required for making chloroben/.cne are ben/.cne, chlorine, hydrogen, air, and some (race catalysts for special reactions. Benzene used is cither moisture free or is dried with sodium hydroxide before being introduced into the reaction. The chlorine is also moisture free. Before chlorine is introduced to the ben/.enc, 1 to 3 percent hydrogen is added along with sufficient air to reduce the chlorine concentration to between 80 and 85 percent. As shown in Figure 2, the benzene and chlorine streams are fed into tanks containing iron rods. These rods act as a chlorine carrier by forming ferric chloride. Because the reaction is exothermic, a portion of the chlorinated benzene mixture is cooled in a heat exchanger and returned to the reactor. Cooling controls the rale of reaction. FRESH WATER IN HYDROGEN CHLORIDE GAS IN EXHAUST GASES CHILLED MONOCHLOROBENZENE HYDROGEN CHLORIDE GAS NTOWER. [ssnrl 1——I IN i —I ' h NZENE—•» •— •—I IOCHLOROBENZENE t FALLING FILM ABSORBER COOLING WATER OUT PRODUCT ACID BENZENE »TER-H I IATER -t4_ \ " BEN. iZENE TO STORAGE MONOCHLOROBCNZENE PARADICHLOROBENZENE ORTHODICHLOROBENZENE STORAGE Figure 2. Typical by-product hydrochloric acid process (chloro- benzene). The liquid components of the reaction are clJorobenzenes and benzene. The gases from the reactor consist of hydrogen chloride, ben/enc, chlorobenzenes, and air. Product liquid is neutrali/cd with sodium hydroxide and separated into constituents by fractionation. Any separated benzene is returned as process feed. Gases leaving the reactor are processed to recover ben/.cne, chlorobenzenes, and hydrogen chloride gas. These gases arc first scrubbed in a 10 HYDROCHLORIC ACID EMISSIONS ------- packed tower with a chilled mixture of monochlorobenzcne and dichlorobenzene to condense and recover any benzene or chlorobenzene. The hydrogen chloride is then absorbed in a falling film absorption plant as described in the section on absorption systems. The chlorobenzene scrubbing liquid is recycled to the main reaction vessel. EMISSIONS Hydrogen chloride emission data, in addition to data on other trace emissions from by-product plants, are presented in Table 3. Most of the plants contacted by questionnaire (^Plants Number 1 through 17) indicated no emissions of hydrogen chloride. However, further investigation indicated that a value of 0.5 percent hydrogen chloride by volume in the exit gas is considered by most plants to be negligible and is therefore reported as zero. Two of the four plants tested by the PHS sampling team (Plants Number 18 through 21), however, showed results somewhat higher than the reporting plants. To ensure more accurate results, greater effort was expended by the sampling team in making these tests than would normally be used in making routine analyses. Concentration of hydrogen chloride in the emissions to the atmosphere range from 0 to 50.6 percent by volume. Because of the diverse methods of production, no correlation exists between exit gas volumes and plant productiori~Yates. However, smaller volumes of exit gas usually show greater hydrogen chloride concentrations. This variation in concentration in exit gas is partly due to the varying amounts of inert materials in this gas stream. For this reason the amount of hydrogen chloride emitted in pounds per ton of acid produced gives a more accurate picture of the contaminant emissions. On this basis emissions range from 0 to 8.5 pounds of hydrogen chloride per ton of actual acid produced. In plant BP-19, where the 8.5 value was recorded, the hydrogen chloride was emitted during a period of about 30 minutes of a 4-hour test period. This particular plant was arranged so that two separate chlorination units were connected to one acid plant. In this test one unit was turned on too rapidly and hydrogen chloride was blown out of the absorption plant until the unit could be stabilized. This represents an example of improper operation because this unit could have been turned on gradually and the hydrogen chloride emitted to the atmosphere would have remained in the range of 0.16 to 0.24 pound per ton as it was in the two 1 -hour tests that followed. Plant BP-21 emitted about 2.6 pounds of hydrogen chloride per ton of acid produced. This plant was not equipped with a final scrubber, a fact which partially accounts for the higher hydrogen chloride emission rate. However, mixing this gas with the exhaust gases from a 1,0,00,000-Btu-per-hour boiler dilutes the emissions to the atmosphere. A hydrogen chloride emission concentration of 0.5 percent at an exit gas flow rate of 40 cubic feet per minute will result in an emission rate of about 1.2 pounds of hydrogen chloride per hour. CONTROL OF HYDROGEN CHLORIDE EMISSIONS Tail gas concentrations of contaminants emitted from a typical by-product plant are often reduced by scrubbing in a packed tower located behind the Acid Manufacturing Processes 11 ------- Table 3. EMISSIONS FROM BY-PRODUCT HYDROCHLORIC ACID MANUFACTURING PLANTS Plant number BP-1 BP-2 BP-3 BP-4 BP-5 BP-e BP-7 BP-8 BP-9 BP-10 BP-11 BP-12 BP-13 BP-14 BP-1S BP-16 BP-17 BP-18b BP-19b BP-200 BP-21b Plant capacity, tons per day 115 40 30 15 220 70 16 7 76 12 26 30 30 105 141.5 17.8 8.3 90 60 140 226 Add concentration. 'Be" 20 20 20 20 20 22 20 22 22 20 20 20 20 20 22 22 22 20 20 20 20 20 Exit gai eondltloni Volume, cfm 200 0 0 NA 2 180 NA 0 270 NA 0.01 Leakage only 10 315° 138° NA 0.1-3.5 520 187 187 8.3 Temperature, °F 180 60 NA NA 100 50 NA 85 104 NA 60 85 100 70 70 70 108 75 57 40 50 Percent HCI« 0 NA NA NA 0 0 0 0 NA NA 0.01 NA 3 0 0 0 0 <0.001 0.024 0.160 1.95 0.0023 0.0019 0.0745 50.6 47.2 53.9 Control equipment Water jets on storage tanks Water scrubber None Caustic scrubber None None None Water scrubber backup Phosgene decom- position towers None None Fume jet None Closed system Closed system None Na3CO3 scrubber Caustic scrubber Water scrubber Water scrubber None for HCI, CCU scrubber for chlorine Substances other than HCI entering atmosphere Air, hydrogen, carbon monoxide and dioxide Trace inerts NA NA Air, carbon dioxide Air, benzol None None Nitrogen and Phosgene NA Water vapor Chlorine Air, organic* Methane, nitrogen, RCI Chlorine, R Cl Inerts Chlorine Nitrogen, traces of eromatics NA Organics Chlorine, carbon dioxide Pounds HCI emitted per ton of 20° Be' «cid produced11 None Nora None None None None None None None None None None 1 None None None None <0.008 0.10 0.70 8.5 0.0044 0.0037 0.14 2.6 2.5 NA not available. •Represents 0.6 percent HCI or leu. "Temd by PHS sempKn»t»eni. eRecycled-c1osed system. ------- final process tower. Venturi scrubbers are also used occasionally. If hydrogen chloride is the only component to be removed, water is universally used as the scrubbing agent. As shown in Table 3, water scrubbers can reduce hydrogen chloride concentration to less than 0.1 pound of HC1 emitted per ton of acid produced. Alkaline scrubbing is sometimes employed when the gases contain substances like chlorine or phosgene, which are not readily absorbed in water. Removal of organic materials from exhaust gases poses a separate design problem for each specific compound. If phosgene is present, a decomposition system is needed. If benzene or phenol is present, scrubbing with a solvent is necessary. In some cases use of the proper scrubbing solution will efficiently remove all of the organic compounds present. Some plants use a completely closed system from which there is no continuous emission of exhaust gases to the atmosphere. By-product hydrogen chloride plants, by their nature, are adjuncts to other processes; therefore, they may be affected by upsets that occur in the process in which the hydrogen chloride is evolved. Good controls and secondary scrubbing systems can reduce the possibility of increasing emissions resulting from such upsets. SYNTHESIS PROCESS Introduction High-purity concentrated hydrogen chloride may be synthesized by burning hydrogen in chlorine, as shown in Figures 3 and 4. High purity is desirable for organic compound or drug synthesis and in the manufacture of reagent-grade acid. Hydrogen chloride is made in accordance with the equation: H2 + C12 > 2 HC1 The source of chlorine is usually chlorine cell gas, although waste chlorine (blow gas) can be used. Hydrogen can come from any source of relatively pure hydrogen, but usually it is from the electrolysis of brine or steam reforming of a relatively pure organic compound. The.purity of the raw materials determines the purity of the product. Chlorine usually contains some organic materials and oxygen in addition to water that can result in water vapor within the combustion chamber. Hydrogen may also contain water vapor and organic compounds. The net result of water vapor in the feed gases is that it can condense in the'combustion chamber and form hydrochloric acid. This may cause corrosion unless impervious graphite materials are used in the combustion chamber. A typical product will contain 0.5 percent hydrogen, 0.1 percent water vapor, 0.1 to 1.5 percent inerts, and the balance hydrogen chloride. In addition, some carbon dioxide may be present. A slight excess of hydrogen is used in this process, and this assures a chlorine-free product. Combustion takes place in a closed chamber under a slight positive or slight negative pressure, depending on chamber type. A burner, shown in Figure 4, injects the chlorine into a surrounding hydrogen Acid Manufacturing Processes 13 ------- WASHER AND MIST ELIMINATOR a § o o 93 hH O > O 8 K) I BURNER CHAMBER PRODUCT GASES (HCI, Hj, AND WATER VAPOR) HYDROGEN-*- CHLORINE PRODUCT ACID Figure 3. Synthesis chlorine-hydrogen process. ------- stream. The original ignition is initiated by using a retractable air-hydrogen torch or an electrical ignition device. COOLING WATER IN EXPLOSION DOOR COMBUSTION HYDROGEN CHLORIDE COOLING WATER OUT -< «*• CHAMBER ' I BURNER-*- P ISIGHT GLASS ^-••HYDROGEN 4 CHLORINE Figure 4. Synthesis process hydrogen-chloride burner. Synthesis plants differ in detail because of differences in raw material sources and qualities, and plant capacity. However, all plants consist of a chlorine burner, including control and safety devices, and acid purifying and absorption facilities. Burners may be steel with a silica or brick lining, water-jacketed steel, or water-cooled graphite. Brick burners are commonly used, especially for large units, but they have the disadvantage of a high product temperature, i.e., about 2,200° F. Water-jacketed steel is good if the temperature of the jacket is maintained above the dew point of the materials within the burner. The outlet temperature from a water-cooled burner is within a range of 700° to 1,000° F. A burner consists of one or more nozzles, which inject the gases into the combustion chamber, and can have a range of capacity of 8 to 16 tons of hydrogen chloride per day. Control of the gas burner may be manual or automatic. The trend presently is toward automatic operation. Controls include safety devices and purge systems. Burner chambers have an explosion rupture disc to protect the vessel and surrounding area. The inlet gas lines are provided with automatic shutoff valves and seals to prevent back flow of reactants due to reports. An ignition device is sometimes included in the outlet duct to prevent the delivery of an explosive mixture of gases instead of hydrogen chloride. Other control and safety devices include flame sensors; temperature-regulated controls for various purposes; and a purge system, which usually injects carbon dioxide, that operates automatically in case of an interruption in any of the services. The hydrogen chloride formed in the combustion chamber is cooled and absorbed in a hydrochloric acid absorption plant as described in the section on absorption systems. Acid Manufacturing Processes 15 ------- Emissions As shown in Table 4, almost no hydrogen chloride is emitted from synthesis plants. Chlorine is eliminated by combusting it with excess hydrogen. In the plants surveyed, no additional air pollution control equipment is used after the tails tower. The data in Table 4 were obtained from operating plants in response to questionnaires. Table 4. HYDROGEN CHLORIDE EMISSIONS FROfiiSYNTHESIS PLANTS Plant number S-1 S-2 S-3 Plant capacity,8 tons per day 33 100 32.5 Acid concentration. "Be 20 22 20 Exitc Volume, ufm 85 NA 130 las conditions Temperature, °F NA 70 80 Percent HCI <0.01 0 Trace Pounds HCI emitted per ton of 20° Be acid produced <0.035 None Trace a20" 6^(31.5 percent) HCI. NA = not available. During startup and shutdown the possibility exists that chlorine and hydrogen chloride may be released into the air. Normally, an inert purge system is a part of the control system and any chlorine, hydrogen, or hydrogen chloride present in the system is purged through the absorber-cooler and tails tower before a shutdown. In the event of an emergency shutdown of a hydrochloric acid plant, the hydrogen chloride gas source should be shut down first. Liquid flow to absorption equipment should be maintained at a level sufficient to keep all tubes and/or packing wetted and thus prevent hydrogen chloride emissions to the atmosphere. Some weak acid wfll be made during this shutdown period, but this can usually be adjusted by producing material of somewhat higher-than-normal strength later. This technique of maintaining at all times the flow of more liquid than is required for surface wetting should also be used to prevent hydrogen chloride emissions during routine shutdowns and startups. Control of Emissions The design, operation, and maintenance of synthesis plants result in no significant emissions of hydrogen chloride, as shown in Table 4. MANNHEIM PROCESS Introduction The Mannheim process is the principal process used to produce hydrochloric acid from salt and sulfuric acid. It also produces salt cake, Na2SO4, which is used in glass and paper manufacturing. The chemical reactions for the salt and sulfuric acid process are: NaCl + H2SO4 NaHSO4 + HC1 16 HYDROCHLORIC ACID EMISSIONS ------- NaCl + NaHS04 Na2SO4 + HC1 2NaCl + H2S04 Na2S04 + 2HC1 Salt and an excess of sulfuric acid are fed into the top center of a Mannheim furnace, as shown in Figure 5, where the mixture is heated to about 1,000° F. This feed is constantly mixed and moved toward the outside of the furnace by plows until it is discharged through an opening into a pan or conveyor. SALT. /SULFURIC ACID OIL ROTATING ARMS WITH PLOWS 1300° F. COMBUSTION GASES TO STACK -SILICON CARBIDE ARCH 1000° F. GASES TO ABSORPTION SYSTEM 1000° F. SALT CAKE PAN WITH HEARTH Figure 5. Cross-sectional view of Mannheim furnace. Hot gases containing 30 to 60 percent hydrogen chloride in air go to the falling film absorber where the hydrogen chloride is cooled and absorbed. Gases from the furnace contain sulfuric acid vapor that condenses to a mist when the gases are cooled. This mist is partially absorbed together with the hydrogen chloride and becomes an impurity in.the hydrochloric acid. Although the several types of Mannheim furnaces in use differ somewhat in detail, they all consist essentially of stationary circular muffles made up of a pan and a domed cover (Figure 6). Size of the pans ranges from 11 to 18 feet in diameter, and construction is of cast iron or refractory. The dome is cast iron or silicon carbide. Agitation of the reaction mass is accomplished by rotating arms that have plows mounted on a centrally located under-driven shaft. A firebrick enclosure provides insulation and directs combustion gases over the cover. Mannheim furnaces generally have salt cake capacities ranging from 6 to 24 tons per day. , A gas duct, a cyclone, and a gas cooler are usually considered a part of the furnace installation. The gas ducting allows the gases to cool somewhat before entering the cyclone. The cyclone removes the salt cake that is carried out with the gases, and the cooler cools the gases before absorption. A careful choice of construction materials is required. Heat resistance is of primary concern ahead of the cooler, and corrosion resistance is of importance downstream of the cooler where sulfuric and hydrochloric acids have condensed. Acid Manufacturing Processes 17 ------- oo a •< O ffi r i o > o 3 ts SULFURIC ACID CHLORIDE SALT (KCI OR NaCI) COMBUSTION GASES TO STACK CYCLONE ROTATING ARMS pRQDUCT GAS / COOLER. ABSORBER TAILS TOWER TAIL GAS TO ATMOSPHERE MANNHEIM FURNACE SALT CAKE TO COOLING STORAGE AND GRINDING COOLING WATER- COOLING WATER* 2=0- LEAN PROCESS WATER GAS STORAGE PRODUCT ACID Figure 6. Mannheim hydrochloric acid manufacturing process flow diagram. ------- Emissions In addition to hydrogen chloride gas, both sulfuric and hydrochloric acid mists are emitted from Mannheim process plants. Data in Table 5 show that in general, emissions from such plants are higher than those from by-product or synthesis process plants. Data reported by manufacturers and collected by actual test showed hydrogen chloride emissions of 1.3 to 3.8 pounds per ton of acid produced. These emissions are probably higher because of poor operation and maintenance and in some cases poor design of absorption systems. Particulate emissions also occur from the salt cake as it is discharged, pulverized, and handled. During startup and shutdown, emissions will not occur when the exhaust fan is on, and the hydrogen chloride gas and fumes are sucked through the furnace to the absorber. Liquid flow in the absorber must be maintained. Control of Emissions Three basic methods of controlling atmospheric emissions exist. They are proper operation, an efficient emissions collecting system, and effective maintenance. Proper operation assumes good design, and results in maximum product recovery, thus reducing the possibility of hydrogen chloride emissions. An adiabatic wet-scrubbing tower that utilizes hydrochloric acid has been used with good results both to scrub and to cool the furnace gas. To reduce atmospheric emissions, a scrubber system can be installed on the tails tower exhaust. Scrubbers presently in use for this purpose include venturi scrubbers and packed water scrubbing towers. The few remaining Mannheim plants in this country are gradually being retired from service because of their high cost of operation and maintenance. HARGREAVES PROCESS Introduction The Hargreaves process was developed in England, and after about 1850 it appeared as if it might become an important source of hydrochloric acid and salt cake. However, new processes were introduced and its use declined. Only one plant of this type is in operation in the United States. In this process, hydrochloric acid is formed by the reaction of sulfur dioxide, steam (water), air (oxygen), and salt at temperatures of about 800 to 1,000° F. The formulas for the reaction are: S + O2 > SO2 2S02 + 4NaCl + 2H20 + O2 * 2Na2S04 + 4HC1 The reaction is exothermic and will maintain itself once the reactants are heated to the proper starting temperature. Emissions The potential emissions from the Hargreaves process are unreacted sulfur dioxide, hydrogen chloride, and salt dust. Dusts are removed initially by Acid Manufacturing Processes 19 ------- Table 5. EMISSIONS FROM MANNHEIM PLANTS Plant number M-1 M-2b Plant capacity,8 tons per day 79 * 10 Acid concentration, °Be 20 20 Exit gas conditions Volume, cfm 440 168 Temperature, °F 150 95 Percent HCI 0.46 0.16; 0.18 0.06; 0.14 Control equipment None Water scrubber Substances other Than HCI present in exit gas H2SO4, 30ppm H2S04 and S02 0-160 ppm Pounds HCI emitted per ton of 20° Be acid produced 3.0 Gas 3.5, 3.9 1.3,3.1 Mist 0.04-0.065 8 £ 8 Q § H I CO a20° Be" (31.5%) HCI. bTested by MCA-PHS. ------- cleaning the product gas with a cyclone. During periods of operational upsets or additions of new salt, hydrogen chloride or sulfur dioxide can be emitted to the air. Since the reaction occurs at 1,000° F, it is desirable to interrupt the process as little as possible, thereby preventing loss of heat and excessive emissions. LAURY PROCESS Introduction In the Laury process, hydrochloric acid is produced in a rotary furnace from the reaction of sodium chloride and sulfuric acid. The equations are: NaCl + H,S04 Nad + NaHSO4 NaHSO4 HC1 Na2SO4 + HC1 A Laury furnace consists of an oil-fired combustion chamber that discharges into a horizontal revolving drum containing a roasting section and a grinding section (See Figure 7). Materials are charged at the end opposite the heating source. As they move counter-current to the flow of hot gases, they are mixed, ground, and roasted. The flue gases and hydrogen chloride from the roasting processes are exhausted at the same end of the drum in which the sodium chloride and sulfuric acid are charged. The hydrogen chloride gas and flue gas from the furnace are exhausted first through either a settling chamber or a cyclone to collect the dust, and then are sent to the hydrochloric acid absorber section of the plant. TO STACK t SALT AND FH HOT SECTION NITRE CAKE GRINDING CHAMBER [ 11 — SALT CAKE TO COHVI Figure 7. Cross-sectional view of Laury furnace. This process was used before the introduction of the falling film absorber and probably all units were installed with two packed columns to absorb the hydrogen chloride. No plants of this type currently operate in the United States. Emissions Emissions of hydrogen chloride from this process are low in concentration but high in volume. Other emissions from this process include salt cake dust Acid Manufacturing Processes 21 ------- and sulfuric acid mist. Salt cake dust is eliminated by a dust removal system or is removed in the acid absorption system. 22 HYDROCHLORIC ACID EMISSIONS ------- ANHYDROUS HYDROGEN CHLORIDE INTRODUCTION Anhydrous hydrogen chloride is sometimes recovered without further processing from the synthesis process. It is also produced from aqueous acid in three basic steps: 1. Thermal stripping of a strong hydrochloric acid feed to the 21 percent azeotropic mixture. 2. Cooling, condensing, and recycling part of the hydrogen chloride as reflux. 3. Cooling and removing the moisture from the gas. Strong hydrochloric acid from storage is stripped in an impervious carbon or graphite shell-and-tube stripper or a similarly packed stripping column (Figure 8). A reboiler is required at the base of the stripper to provide thermal energy for the liquid-gas separation. Spent acid leaves the bottom of the stripper. This acid is either cooled and stored or sent to the concentration unit for cooling and concentration in a falling film absorber. CONDENSER COOLING BRINE PURE WATER CONDENSER TRAP FILTER TO REMOVE WATER .ING BRINE I 1~ ju I PRODUCTSOLU 1 ' nr Mri DRY HO GAS l-4-TREATED ACID FEED 31.5 PERCENT PACKED SECTION' = | » SPENT ACID OUT II PERCENT Figure 8. Hydrogen chloride distillation system for reagent-quality acids. 23 ------- The hydrogen chloride gas and other vapors from the top of the stripper are passed through a heat exchanger where the condensate is removed and fed back as a reflux to the stripper. The remaining gas, which is substantially pure hydrogen chloride, is then dried in a shell-and-tube condenser with a 0° to 5° F cooling brine and then passed through a particulate entrainment separator for water removal A complete unit that will produce anhydrous acid is available from several hydrochloric acid equipment manufacturing companies. These units operate in a similar fashion to the process described here. EMISSIONS This process yields no emissions to the atmosphere because the manufacturing system is closed and the product vapors are piped directly to the process area. 24 HYDROCHLORIC ACID EMISSIONS ------- REAGENT-GRADE HYDROCHLORIC ACID MANUFACTURE Commercial-grade 31.5 percent hydrochloric acid is distilled in a rectifying column to form reagent-grade 37 to 38 percent hydrochloric acid. Packaged commercial systems for making reagent acid, as illustrated in Figure 8, are available. A system for making the reagent-grade acid may also make dry hydrogen chloride gas and hydrochloric acid solutions. These systems are made up of a boiler at the base of a split column, a feed to the column (at the split section) that serves as reflux for the acid being vaporized, a condenser that forms product hydrogen chloride and refluxes the hydrogen chloride gas section of the column, and a cooler-absorber for forming 31.5 percent hydrochloric acid product if desired. The system is valved so that any one of the three desired products can be made with only a change of valving. A flow diagram of a plant of the type described is illustrated in Figure 8. Other types of plants making reagent-grade acid are not of the "package" type. These plants are constructed largely of glass and have tantalum or titanium heat exchangers for condensing the acid. Any acid must be treated before it is distilled. Minerals and gases, which may carry over with the acid vapors, must be stabilized to stay in the 21 percent azeotropic acid remaining after boiling. Processes for stabilizing the minerals and gases are proprietary and differ with the acid manufacturer. The azeotropic mixture of acid remaining after distillation can be used to absorb more hydrogen chloride and then be redistilled, or it can be used in other processes. Reagent-grade acid may also be made directly from a relatively pure gas such as is produced in the synthesis process without the need for chemical treatment or distillation. EMISSIONS This process yields no emissions to the atmosphere because the manufacturing system is closed. AIR BLOWING Air blowing, used to remove organic substances from hydrochloric acid, can cause hydrogen chloride and organic emissions that can be a potential source of odors. Fortunately, this obsolete practice is seldom used and is of little industrial importance. In the process, air is blown through a sparger installed in a tank of hydrochloric acid to remove dissolved organic gases and to evaporate organic materials in the acid. This blowing may take place for a 30- to 60-minute period. Emissions from air blowing can be eliminated by water scrubbing the gases 25 ------- vented from the tank. A water ejector can be used to remove the fumes from the tank as well as to scrub them. No reports of air blowing practices were obtained during the preparation of this report HYDROGEN CHLORIDE ABSORPTION SYSTEMS Falling Film Absorber The most widely used absorption unit is the falling film system. It consists of a falling film cooler-absorber and a small packed tails tower.5'6 As shown in Figures 9 and 10, the gases and the absorbent, which is usually weak acid, enter at the top of the absorber and the hydrogen chloride is absorbed in the liquid wetting the inside of the tube. The absorption is limited by the number of tubes, which determines the amount of wetted area available for absorption and cooling. After passing through the falling film absorber, the gases pass through a tails tower where the remaining portion of the hydrogen chloride is reduced to less than 0.5 percent of the exit gas. Fresh water, which is used as the absorbant, is fed to this tower, and a weak acid results from the absorption of the hydrogen chloride in the water. Adiabatic Absorber Another system that is relatively new is the adiabatic absorption unit,6 '7 shown in Figure 11. Used to make an organic-free acid, this unit consists of a packed column into which water is fed near the top, and hydrogen chloride near the bottom. Hydrogen chloride and water-contact one another to form hydrochloric acid that is at its boiling point. Excess heat is removed by the formation of steam. Inert substances, steam, and lower-boiling organic materials that cannot condense in the acid because it is at its boiling point are vented from the column. A water ejector-type scrubber is usually used to scrub the gases coming from the column. Further removal of organic materials may be accomplished by cooling the acid and running it through a carbon bed where the organics are absorbed. A variation of this plant is the modified adiabatic absorption unit. It is not a true adiabatic system in the usual sense; it is designed to remove more organic substances and chlorine. In this process, hydrogen chloride gas is injected near the middle of the column to maintain an adiabatic section in the upper portion of the column. Heat then can be added to the bottom of the column to strip the acid in the bottom section of the column. These plants are usually sold complete with instruments. Emissions from Absorber Systems Hydrogen chloride emissions from a falling film absorber may be influenced by several factors.8 These include a lack of cooling and a lack of sufficient weak acid to absorb the hydrogen chloride gas. During startups andi shutdowns when hydrogen chloride gas flow is less than normal, it is possible that'not all of the tubes in the absorber will be wetted if the feed water rate is reduced to maintain product strength. In this situation gas passes through the falling film 26 HYDROCHLORIC ACID EMISSIONS ------- FRESH WATER IN INERTS OUT TO ATMOSPHERE GAS FLOW WEAK HYDROGEN CHLORIDE GAS FROM FALLING FILM ABSORBER TO TAILS TOWER PRODUCT OUT. Figure 9. Falling film absorber with external piping and tails tower. Reagent-Grade 27 ------- VENT _L TAILS TOWER SECTION COOLING WATER •**— FEED WATER COOLING WATER STRONG ACID Figure 10. Falling film absorber with integral gas piping and tails tower. HYDROCHLORIC ACID EMISSIONS ------- ORGANIC CONTAMINANTS - STEAM CONDENSED STEAM*. ORGANICS - CHLORINE AND ORGANIC 1. ADIABATIC ABSORPTION TOWER RECEIVES BY-PRODUCT HCI GAS STREAM CONTAMINATED WITH ORGANICS. ABSORPTION OF HCI IN WATER GENERATES HEAT. 2. TOWER OVERHEAD CONDENSES BY DIRECT CONTACT FUME SCRUBBER. 3. HOT HCI SOLUTION COOLED BY SHELL AND TUBE COOLER. 4. COOLED HCI SOLUTION PUMPED TO EITHER OF TWO ACTIVATED CARBON ADSORBERS ACTING ON ADSORB-REGENERATE CYCLE. ORGANIC CONTAMINANTS ADSORBED IN CARBON RESULTING IN FINISHED ACID. 32% CONCENTRATION CONTAINING LESS THAN 1 ppm ORGANICS AT 100-F. ACID NOW TRANSFERRED TO STORAGE AREA. Figure 11. Typical adiabatic hydrochloric acid absorption unit flow diagram. unit and overloads the tails tower, which also is receiving less than a normal amount of feed water. The solution to this problem is to maintain a minimum flow sufficient to wet the tubes. Weak acid produced during these periods can either be discarded or concentrated by making higher-strength acid when normal conditions are restored. The adiabatic absorption unit is not nearly as sensitive to cooling problems as the falling film unit because heat is removed by the^ormation of steam. It is, however, just as likely to produce hydrogen chloride emissions if all of the packing is not wetted The technique of maintaining minimum liquid flow as described above is also effective with the adiabatic unit. The adiabatic unit, with its. counter flow liquid and gas, is more easily flooded than the parallel-flow falling film unit. Control of Emissions Hydrogen chloride emissions may be effectively controlled by installing any of several types of scrubbers after the tails tower in the case of the falling film unit and after the adiabatic tower in the case of the adiabatic unit. Regardless Reagent-Grade 29 ------- of the type of absorption unit used for making hydrochloric acid, the best design is characterized by a final scrubber to remove residual hydrogen chloride passing through the system An adiabatic absorption system normally has a scrubber designed to reduce the hydrogen chloride content of the gases emitted to 0.5 percent or less by volume. 30 HYDROCHLORIC ACID EMISSIONS ------- DEFINITIONS Absorber Absorption system Acid mist BaimuS (Be) Contaminant Emission Establishment Muriatic acid Rant Reforming Tail gas Chemical equipment that serves to contact a gas or vapor with a liquid so that gas or vapor is absorbed into the liquid. In this report, it refers to equipment used to contact hydrogen chloride with water to form hydrochloric acid. An absorber or several absorbers used to absorb hydrogen chloride. Extremely small particles of liquid acid that are suspended in a gas or vapor. Acid strength is determined by use of a floating instrument (hydrometer) calibrated to read degrees Baume and by a conversion chart. The Baume can also be calculated if the specific gravity of the acid is known: .*? ' Be =145- (||) Any substance not normally found in the atmosphere. Any gas or vapor stream emitted to the atmosphere. A works having one or more hydrochloric acid plants or units, each of which is a complete production entity. 20° Be hydrochloric acid. A chemical works at whidh hydrogen chloride is manufactured and converted with an absorption unit into hydrochloric acid. Burning an organic fuel in the presence of water or water vapor in such a manner that hydrogen-rich gas is formed. Gases and vapors that leave hydrochloric acid absorption units. 31 ------- APPENDICES A. SAMPLING AND ANALYTICAL TECHNIQUES B. HYDROCHLORIC ACID MANUFACTURING ESTABLISHMENTS LOCATED IN UNITED STATES C PHYSICAL DATA-HYDROCHLORIC ACID 33 ------- APPENDIX A. SAMPLING AND ANALYTICAL TECHNIQUES DETERMINATION OF HYDROGEN CHLORIDE AND CHLORINE IN STACK GAS. The method discussed herein is used to determine the presence of hydrogen chloride in the stack gases from hydrochloric acid manufacturing processes. Samples are collected from the gas stream in either midget impingers or a grab-sampling bottle containing sodium hydroxide, and hydrogen chloride is determined by the Volhard titration.9 If chlorine is suspected to be present in the stack emission, another sample is collected in a similar manner, except that a known quantity of alkaline arsenite absorbing reagent is substituted for sodium hydroxide. Chlorine is reduced to chloride by arsenite, and is measured by titration of the unconsumed arsenite with standard iodine solution. Total chloride content of the sample is determined by the Volhard titration. Hydrogen chloride concentration is calculated by subtraction of the chlorine concentration from total chloride concentration. This method is applicable in determining hydrogen chloride and chlorine concentrations ranging from 10 ppm to percentage quantities. Reagents All chemicals must be ACS analytical reagent-grade. Water Deionized or distilled water. Absorbing Reagents: 1. Sodium hydroxide (IN)- Dissolve 40 g of sodium hydroxide in water and dilute to 1 liter. This reagent is used when the stack gas concentration of hydrogen chloride is suspected to be less than 1,000 ppm. 2. Sodium hydroxide ( 2.5 N) - Dissolve 100 g of sodium hydroxide in water and dilute to 1 liter. This reagent is used when the stack gas concentration of hydrogen chloride is suspected to be greater than 1,000 ppm. 3. Alkaline arsenite (IN NaOH and 0.1 N NaAsO2 ) Dissolve 40 g of NaOH and 6.5 g of sodium arsenite ( NaAs02 ) in water and dilute to 1 liter in a volumetric flask. This reagent is used when the stack gas concentration of hydrogen chloride and C12 is suspected to be less than 1,000 ppm. 4. Alkaline arsenite ( 2.5 N NaOH and 0.5 N NaAsO2 ) Dissolve 100 g of NaOH and 32.5 g of NaAsO2 in water and dilute to ] liter in a volumetric flask. This reagent is used when the stack gas concentration of hydrogen chloride and C12 is suspected to be greater than 1,000 ppm. 34 HYDROCHLORIC ACID EMISSIONS ------- Ferric Alum Indicator Dissolve 28.0 g of ferric ammonium sulfate FeNH4 ( SO4 )2 • 12 H2O in 70 ml of hot water. Cool, filter, add 10 ml of concentrated nitric acid( HNO3 ), and dilute to 100 ml in a volumetric flask. Nitric Acid (8N) Prepare NOx-free nitric acid by adding 100 ml of HN03 to 100 ml of water and boiling in a flask until the solution is colorless. Store in a glass reagent bottle. Nitrobenzene Reagent grade. Sodium Chloride (Primary Standards) 1. NaCl (0.1 N) - Dissolve 5.846 g of dried sodium chloride (NaCl) in water and dilute to 1 liter in a volumetric flask. 2. NaCl ( 0.01 N ) - Dissolve 0.5846 g of dried NaCl in water and dilute to 1 liter in a volumetric flask, or dilute 100 ml of 0.1 N NaCl to 1 liter. Ammonium Thiocyanate 1. NH4CNS ( 0.1 N ) - Dissolve 8 g of NH4CNS in water and dilute to 1 liter in a volumetric flask. 2. N^CNS ( 0.01 N ) - Dilute 100 ml of 0.1 N NH,CNS to 1 liter in a volumetric flask, or dissolve 0.8 g NUjCNS in 1 liter of distilled water. Silver Nitrate 1. AgNC-3 ( O.I N) - Dissolve 17.0 g of silver nitrate ( AgN03 ) in water and dilute to 1 liter in a volumetric flask. Transfer to an amber reagent bottle. Standardize this solution against 0.1 N NaCl solution, according to the Volhard titration.9 2. AgN03 'C0.01 N) - Dissolve 1.7 g of AgN03 in water and dilute to 1 liter in a volumetric flask. Transfer to an amber reagent bottle. Standardize this solution against standard 0.01 N NaCl solution, according to the Volhard titration. Starch Solution (Iodine Indicator), 1.0% Make a thin paste of 1 g of soluble starch in cold water and pour into 100 ml of boiling water while stirring. Boil for a few minutes. Store in a glass-stoppered bottle. Standard Iodine Solution ( 0.1 N ) ' Dissolve 12.69 g of resublimed iodine (I2 ) in 25 ml of a solution containing 15 g of iodate-free potassium iodine (KI); dilute to 1 liter in a volumetric flask. Standardize this solution against a standard tliiosulfate solution using starch as an indicator. This solution should be stored in an amber reagent bottle and refrigerated when not in use. Apparatus (See Figures A-l and A-2) Appendix A 35 ------- Sampling Probe 10-mm Pyrex® glass tubing of any convenient length. Filter A small fiberglass filter may be fitted to the probe inlet when particulate matter is present in the gas stream being sampled. Heating Tape Used to heat probe. Variable Voltage Regulator Used to regulate probe heating. Dry Gas Meter Readable to the nearest 0.01 cubic foot. Vacuum Pump A diaphragm-type pump rated at 15 liters per minute. Absorbers 1. Midget impinger — An all-glass midget impinger sampling train capable of removing hydrogen chloride and chlorine from a gas sample may be used when sampling stack gas suspected of containing less than 0.1 percent hydrogen chloride or chlorine. The sampling train should consist of a probe, four midget impingers, a gas drying tube, a vacuum pump, and a flow meter, as illustrated in Figure A-l. PROBE WITH HEATING ELEMENT ICE BATH I METER Figure A-l. Impinger gas sampling train. A Pyrex® glass tube serves as the probe. It should have a ball joint on the outlet to which other glassware can be easily connected. The probe should be wrapped with nickel-chromium heating wire, insulated with glass wool and installed into a protective 1-inch-diameter stainless steel 36 HYDROCHLORIC ACID EMISSIONS ------- tube. During sampling, the heating wire is connected to a calibrated, variable transformer to maintain a temperature of up to 250° F on the probe wall. A heating tape may also be used to heat the probe. Four midget glass impingcrs are connected in series to the probe outlet with glass ball joints. The first three impingers each contain 15 ml of absorbing reagent. The fourth impinger is left dry to catch any material that is carried over from the other impingers. All four impingcrs are cooled in an iccwatcr bath. Gases leaving the impingers are dried as they pass through a tube of silica gel. They then are pumped to the airtight vacuum pump and gas meter. Sampling rales are regulated by using a valve to adjust the flow through the pump. 2. Grab-sampling bottle An accurately calibrated 2-liter glass bottle equipped with Teflon® stopcocks (Figure A-2) should be used when sampling percentage quantities of hydrogen chloride or chlorine. Absorbing reagent is added to the grab-sample bottle after the sample has been collected. ATTACH ^ ^ TO PROBE VACUUM Figure A-2. Grab sample bottle. Dispenser (Absorbing Reagent) A 100-milliliter round-bottom flask, modified with a Teflon® stopcock and ball joint extension (see Figure A-3) is used as a dispenser for absorbing reagent. It is used to add reagent to the grab-sampling bottle after the sample has been collected. Analytical Procedure Collection of Samples 1. Midget impinger train: Pipet 15 ml of absorbing reagent into each of the three midget impingers. Heat probe to prevent moisture condensation. Start pump and sample at a rate of 1 to 3 liters per minute for at least 60 minutes. 2. Grab sampling: Flush probe and draw about 20 liters of gas through the sample bottle. Pipct 25 ml of absorbing reagent into the dispenser and add to the grab-sample bottle following collection of the sample. Shake bottle thoroughly for about 2 minutes to insure complete absorption. 3. Transfer the contents of the impingers or grab-sampling bottle to a sample container, such as a polyethylene bottle, containing deionixed or distilled water. Appendix A 37 ------- 100-ml CAPACITY NO. 12/5 'TEFLON STOPCOCK Figure A-3. Burette for adding absorbing reagent. Sample Preparation Measure the actual volume of the liquid sample or adjust to a known volume using a graduated cylinder or volumetric flask. Procedure A Analysis of Hydrogen Chloride Pipet an aliquot of the sample into a 250-ml Erlenmeycr flask. Add 25 ml of water, 5 ml of nitric acid and swirl to mix. Depending on chloride content, add O.I N or 0.01 N silver nitrate from a buret until the silver chloride formed begins to coagulate. When coagulation occurs, add an additional S ml of silver nitrate. Add 3 ml of nitrobenzene and 2 ml of ferric indicator, then back-titrate with 0.1 N or 0.01 N ammonium thiocyanate until the First appearance of the reddish-brown Fe(CNS)6~3 complex. A blank determination for chloride in the absorbing reagent should be run simultaneously and subtracted from the sample results. From the titcr of NH4CNS solution, as determined previously by titration against standard AgNO3 solution using ferric alum as an indicator, calculate the net volume of AgNO3 required for precipitation of the chloride. Calculations Compute the number of milligrams of hydrogen chloride present in the sample by the following equation: 38 HYDROCHLORIC ACID EMISSIONS ------- C = Hd, mg = net ml AgN03 X T X F T = hy drogen chloride equivalent of standard AgNO3 ( T = 3.65 mg HCl/ml for 0.1 N AgN03 ) ( T = 0.365 mg HCl/ml for 0.01 N AgNO3 ) „ sample volume, ml r — aliquot volume, ml Convert the volume of gas sampled to the volume at standard conditions of 70° F and 29.92 in. Hg. 530°R 29.92 ( t + 460 R) V = volume of gas sampled, as measured on dry gas meter or equal to volume of grab sample bottle-liters P = barometric pressure (in. Hg) or absolute pressure at gas meter t = average temperature of gas sampled, ° R Determine the concentration of hydrogen chloride in the gas sample by the following formula: Vs 662 = jul/mg of HC1 at 70° F and 29.92 in. Hg C = concentration of HC1, mg V s = volume of gas sampled in liters at 70° F and 29.92 in. Hg Procedure R Analysis of Hydrogen Chloride in the Presence of Chlorine Pipet an aliquot of the sample into a 250-ml Erlenmeyqr flask and proceed with the Volhard titration for total chlorides as described under Procedure A. A blank determination for chloride in the absorbing reagent (alkaline-arscnite reagent) should be run simultaneously and subtracted from the sample results. Pipet another aliquot of the sample into a 250-ml Erlenmeyer flask. Add a few drops of phenolphthalein indicator, neutralize carefully with concentrated hydrochloric acid, and cool. Add sufficient solid sodium bicarbonate ( NaHCO3 ) to neutralize any excess hydrochloric acid, then add 2 to 3 g more. Add 2 ml of starch indicator and titrate with 0.1 N iodine solution to the blue endpoint. For the reagent blank, determine the number of ml of 0.1 N 12 required to titrate 25 ml of alkaline-arsenite absorbing reagent, as described above. Appendix A 39 ------- Calculations Determine the number of milliliters of 0.1 N I2 required to titrate the entire sample by the following formula: Sample ( ml 0.1 N I2 ) = ( ml of 0.1 N 12 for aliquot) X F volume of sample, ml P _ volume of aliquot, ml Cl2,mg = Blank ( ml 0.1 NI2) Sample(ml0.1 NI2) X 3.546 3.546 = chlorine equivalent of 0.1 N I2, mg Convert the volume of gas sampled at standard conditions of 70° F, 29.92 in. Hg, using the formula in Procedure A. Calculate the concentration of C12 in the sample using the following formula: (340) (C) ppm C12 by volume = — "s 340 = 1/mg of C12 at 70° F and 29.92 in. Hg C = concentration of C12, mg V s = volume of gas sampled at standard conditions, liters Determine the number of milligrams of hydrogen chloride present in the sample by subtracting the number of milligrams of chlorine present, as determined by the iodine titration, from the total number of milligrams of chloride present as determined by the Volhard titration. Calculate the concentration of hydrogen chloride in parts per million using the formula in Procedure A. Total stack gas volume must also be measured in order to determine the emissions on a weight basis. This may be done by measuring the gas velocity with a pitot tube. The following equations are used to determine gas velocity and gas volume: = 172(F)(VAPavg) |\/TS.X L X — MS Vg = velocity in feet per minute at stack conditions F = pitot tube—correction factor (0.85 for type S) Mo = molecular weight of stack gas To = average stack gas temperature ° R Po = average stack gas pressure, in. Hg AP = pitot tube manometer reading, in. water 40 HYDROCHLORIC ACID EMISSIONS ------- The total stack gas volume-is then: TPc" (17.4) A = stack area, sq ft Qs = gas volume, ft3/minat 70° F and 29.92 in. Hg The emissions on a weight per hour basis may then be determined by the following equation: W = ppm X 10-6 X Q X 60 X s 387 W = emissions, Ib/hr ppm = parts per million by volume of contaminant Qs = stack gas flow rate, scfm mol wt = molecular weight of contaminant C12 = 70.92 HC1 = .36.46 387 = volume (ft3) occupied by 1 Ib mol at 70° F and 29.92 in. Hg Discussion of Procedure: The estimated error for the combined sampling and analytical procedure is ±10 percent. The precision of the analytical methods is ±2 percent on standard samples containing NaCl and NaAsO2. The usual volumetric errors are encountered with the Volhard titration. Premature endpoints may occur if the NH4 CNS is not added by drops near the equivalence point and the solution shaken before the next addition. Nitrobenzene is used to effectively remove AgCl by forming an oily coating on the precipitate and preventing reaction with the thiocyanate.10 Bivalent mercury, which forms a stable complexion with the thiocyanate, and substances that form insoluble silver salts interfere in the analysis and must be absent from the sample. Titration should be made at temperatures below 25° C, as is customary in other titrations with thiocyanate.11 The chief source of error in the iodine titration of arsenite is the failure to use sufficient bicarbonate to neutralize all the excess acid. If insufficient bicarbonate is added, serious errors may be incurred because of a fading endpoint. A reducing agent such as sulfur dioxide and oxidizing agents such as iodine, nitrogen dioxide, and ozone interfere with the iodine titration and yield high results when present in the stack gas sample. ACID MIST SAMPLING. The sampling apparatus is made up of a probe, a cyclone, a filter, four impingers, a dry gas meter, a vacuum pump, and a flow meter, as shown in Figure A-4.12'13 Appendix A 41 ------- Figure A-4. Mist sampling train. A stainless steel, buttonhook-type probe tip (1) is connected to the probe by a stainless steel coupling (2) and Viton® "0" ring bushings. The probe (3) is a 5/8-inch-outside-diameter medium-wall Pyrex® glass tube with an §-ball joint on one end. The glass probe is wound from the entrance end with 25 feet of 26 guage nickel-chromium wire. During sampling the wire is connected to a calibrated variable transformer to maintain a gas temperature of 250° F in the probe. The wire-wound glass tube is wrapped with fiberglass tape and encased in a 1-inch-outside-diameter stainless steel tube for protection. A glass cyclone (4) is connected to the outlet end of the probe to catch larger size mists. A very coarse-fritted glass filter holder (5), which holds a 2-H-inch tared glass fiber filter of MSA type 1106 BH filter paper, follows the cyclone. The cyclone and filter are contained in an electrically heated, enclosed box (6), the temperature of which is thermostatically maintained at a minimum of 250° F to prevent condensation of water. Four impingers in series, placed in an ice bath, are connected to the filter holder outlet. The first impinger is a Greenburg-Smith design modified by replacing the tip with a H-inch diameter glass tube extending to 0.5 inch from the bottom of the flask. This impinger contains 100 ml of sodium hydroxide. The second impinger is a Greenburg-Smith impinger with tip that also contains 100 ml of sodium hydroxide. The third impinger is modified the same as the first and is left dry. The fourth impinger (11) is also a modified Greenburg-Smith type. It contains about 175 g of dry silica gel. From the fourth impinger (11) the effluent stream flows through a check valve (13), a needle valve, a leakless vacuum pump, and a dry gas meter. A calibrated orifice and a dual manometer complete the train and are j used to measure instantaneous flow rates. 42 HYDROCHLORIC ACID EMISSIONS ------- DETERMINATION OF SULFATES AND SULFURIC ACID. This method is used to determine concentrations of sulfuric acid or sulfur dioxide14 in stack gases from the manufacture of hydrochloric acid by the Mannheim process. Sulfur dioxide in the stack effluent is absorbed and oxidized to the sulfate form in midget impingcrs containing 3 percent hydrogen peroxide. Sulfuric acid mist is collected on a glass fiber filter paper by an acid mist sampling train. Sulfates are determined turbidimetrically by the formation of barium sulfate as barium chloride is added. The absorbance of the barium sulfate suspension is measured spectrophotometrically at 500 m/* with a 1-inch cell path. This method is applicable for the determination of sulfate ion concentrations of from 0 to 50 Mg/ml in aqueous media. Reagents All chemicals must be ACS analytical reagent grade. Water Deionized or distilled water. Absorbing Reagent Hydrogen peroxide (3 percent) — Dilute 10 ml of 30 percent hydrogen peroxide to 100 ml. Sulfa Ver Powder For sulfates in water manufactured by the Hack Chemical Company, Ames, Iowa.* Standard Sodium Sulfate Dissolve 1.469 grams of sodium sulfate in 1 liter of water. Dilute 100.0 ml of this solution to 1 liter with water in a volumetric flask. This solution contains 100Mg(S04')/mL Sample Preparation Transfer the contents of the midget impingers or the glass fiber filter to a sample container. Dilute the impinger solution to a known volume and/or add a known volume of water to the filter for solubalization of the sulfate. Procedure Pipet 20 ml or a suitable aliquot made up to 20 ml into a 1-inch cuvette or test tube. Read the absorbance against a distilled water blank (blank correction). This value will be subtracted from the final absorbance reading to correct for unmatched cuvettes. Add one level spoonful (0.3 g) of Sulfa Ver powder and shake to mix. Between 5 minutes and 20 minutes after the Sulfa Ver powder is added, the absorbance should be read on'a spectrophotometer at 500 rh/Lt. Use a blank of *Mcntion of company or product name does not constitute endorsement by the U.S. Department of Health, Education, and Welfare. Appendix A 43 ------- water and Sulfa Ver powder to set the spectrophotometer to zero absorbance. Determine the amount of sulfate present from a previously prepared calibration curve. Preparation of Calibration Curve Prepare a series of standards ranging from 0 to 50 Mg/ml from the working standards solution. Measure the absorbance of these standard solutions in the manner described in the procedure. Construct a calibration curve by plotting /ug (S04 )/ml versus absorbance. Calculations Compute the number of mg of SO2 present in the sample by the following formula: 64 = molecular weight of SO2 96 = molecular weight of (S04) Compute mg of H2 SO4 present in the sample by the following formula: no H2S04,mg = (SOi),mgX 96 = molecular weight of (SO4) 98 = molecular weight of sulfuric acid. (377)(mgofS02) SO2,ppm = - T; V s 377 = jd/mg of S02 at 70° F and 29.92 inches of Hg V s = volume of gas sampled in liters at 70° F and 29.92 inches of Hg , H2SO4,/ug H2S04,|Ug/m3 = ' v s V s = volume of gas sampled in cubic meters at 70° F and 29.92 inches of Hg 44 HYDROCHLORIC ACID EMISSIONS ------- APPENDIX 6. HYDROCHLORIC ACID MANUFACTURING ESTABLISHMENTS LOCATED IN UNITED STATES January 1968 Type of Process Utilized B = By-Product S = Chlorine-Hydrogen Synthesis M = Mannheim H = Hargreaves State Company name Alabama Giegy Chemical Corp. Monsanto Co. Olin Matheison Chemical Corp. Olin Matheison Chemical Corp. Stauffer Chemical Arkansas Arkla Chemical Corp. California American Chemical Corp. J.H. Baxter & Company Chevron Chemical Company Dow Chemical Co. E.I. duPont dcNemours & Co. Neville Chemical Co. Stauffer Chemical Co. Montrose Chemical Corp. of Calif. Witficld Chemical Corp. Connecticut The Upjohn Co. Uniroyal Co. Delaware Allied Chemical Corp. Standard Chlorine of Delaware Location Type Mclntosh B Anniston B Mclntosh B Huntsville B LeMoyne B Pine Bluff Long Beach B Long Beach B Richmond B Pittsburgh B Antioch B Santa Fe Springs B Domingue/. (LA.) B Torrance B Watson B North Haven B Naugatuck B North Claymont B Delaware City B Appendix B • 45 ------- Georgia Chemical Products Corp. Cartersville Hercules, Inc. Brunswick Merck & Company Albany Illinois Allied Chemical Corp. Danville Baird Chemical Industries, Inc. Peoria Cabot Corp. Tuscola Monsanto Co. Sauget The Richardson Co. Chicago The Richardson Co. Lemont Indiana E.I. duPont deNemours & Co. East Chicago Keil Chemical Hammond B B B B B B B B B B B Kansas Racon, Inc. Vulcan Materials Co. Clearwater Wichita B B,S Kentucky E.I. duPont deNemours & Co. Louisville Hooker Chemical Corp. South Shore Pennsalt Chemical Corp. Calvert City Stauffer Chemical Co. Louisville B B B B Louisiana Allied Chemical Corp. Geismar Allied Chemical Corp. Baton Rouge Conoco Lake Charles Dow Chemical Co. Plaquemine Ethyl Corp. Baton Rouge Hooker Chemical Co. Taft Kaiser Aluminum & Chemical Co. Gramercy Morton Chemical Co. Weeks Island Morton Chemical Co. Giesmar Pittsburgh Hate Glass Co. Lake Charles Rubicon Chemicals, Inc. Lake Charles Shell Chemical Co. Norco Vulcan Materials Co. Geismar Wyandotte Chemical Corp. Geismar B B B B,S B,S B B H B B B B B B Maryland Chemetron Corp. Continental Oil Co. FMC Elkton Baltimore Baltimore B B B 46 HYDROCHLORIC ACID EMISSIONS ------- Massachusetts Monsanto Co. Everett Solvent Chemical Co. Maiden Michigan Dow Chemical Co. Midland Dow Corning Co. Midland E.I. duPont deNemours & Co. Montague Hooker Chemical Corp. Montague Ott Chemical Corp. Muskegon Pennsalt Chemical Corp. Wyandotte Missouri Monsanto St. Louis Nevada Montrose Chemical Corp. of Calif. Henderson Stauffer Chemical Co. Henderson B B B B B S B B,S B B New Jersey Allied Chemical Corp. Elizabeth Baldwin-Montrose Calif. Co. Newark Benzol Products Div. Newark W.A. Cleary Corp. New Brunswick Diamond Alkali Co. Newark E.I. duPont deNemours & Co. Carney's Point E.I. duPont deNemours & Co. Deepwater E.I. duPont deNemours & Co. Linden Enjay Chemical Co. Bayway General Aniline & Film Corp. Linden Hercules, Inc. Parlin ICI Bayonne Merck & Co. Rahway Mobil Oil Corp. Metuchen Pearsall Chemical Corp. Phillipsburg Tenneco Chemical Inc. Fords Toms River Chemical Corp. Toms River Vulcan Materials Co. Newark Weston Chemicals Corp. Newark White Chemicals Co. Bayonne B B B B B B B M B S B B B B B B B B B B New Mexico Climax Chemical Co. Hobbs M New York Allied Chemical Corp. Buffalo Allied Chemical Corp. Syracuse E.I. duPont deNemours & Co. Niagra Falls B B B,S Appendix B 47 ------- Eastman Kodak Co. Hooker Chemical Corp. Hooker Chemical Corp. Stauffcr Chemical Corp. Rochester B Niagra Falls B,S North Tonawanda B,S Niagra Falls B Ohio Detrex Chemical Ind. Ashtabula Diamond Alkali Co. Painesville Dover Chemical Corp. Dover E.I. duPont deNemours & Co. Cleveland Olin Matheison Chemical Corp. Ashtabula Pittsburgh Plate Glass Co. Barberton Tennessee Corp. Evendale B B,S B M B B M Oregon Pennsalt Chemical Corp. Portland Pennsylvania Allegheny Electronic Chemical Co. Bradford Koppers Co., Inc. Bridgeville Lebanon Chemical Co. Lebanon Rohm & Haas Co. Philadelphia U.S. Steel Corp. Clairton B B B B B Tennessee Stauffer Chemical Co. Velsicol Chemical Corp. Mt. Pleasant Chattanooga B B Texas Atlantic Richfield Co. Diamond Alkali Co. Diamond Alkali Co. Dow Chemical Co. Dow Chemical Co. E.I. duPont deNemours & Co. Ethyl Corp. Monsanto Co. Monsanto Co. Phillips Petroleum Co. Phillips Petroleum Co. Potash Co. of America Shell Chemical Co. Stauffer Chemical Co. Union Carbide Corp. The Upjohn Co. Vulcan Materials Co. Port Arthur Deer Park Greens Bayou Freeport Oyster Creek La Porte Houston Texas City Alvin Pasadena Deer Park Dumus Houston Fort Worth Texas City La Porte Denver City B B,S B B B S B,S B B B B B B M B ;B i S 48 HYDROCHLORIC ACID EMISSIONS ------- Utah National Lead Co. Lakepoint (experimental) Virginia Hercules, Inc. Hopewell M Olin Matheison Chemical Corp. Saltville S Washington Hooker Chemical Corp. Tacoma S,B Pennsalt Chemical Corp. Tacoma S Reichhold Chemicals, Inc. Tacoma B West Virginia Allied Chemical Corp. Moundsville B Diamond Alkali Co. Belle B FMC Corp. South Charleston B FMC Corp. Nitro B Mobay Chemical Co. New Martinsville B Monsanto Co. Nitro B Pittsburgh Plate Glass Co. Natrium B,S Stauffer Chemical Co. Gallipolis Ferry B Union Carbide Corp. Institute B Union Carbide Corp. South Charleston B Appendix B 49 ------- APPENDIX C. PHYSICAL DATA-HYDROCHLORIC ACID 51 ------- Table C-1. SPECIFIC GRAVITIES OF AQUEOUS HYDROCHLORIC ACID SOLUTIONS8 Standard Adopted 1903 Authority - W. C. Ferguson Density, °Be 1.00 2.00 3.00 4.00 5.00 5.25 5.50 5.75 6.00 6.25 6.50 6.75 7.00 7.25 7.50 7.75 8.00 8.25 8.50 8.75 9.00 9.25 9.50 9.75 10.00 10.25 10.50 10.75 11.00 11.25 11.50 11.75 12.00 12.25 12.50 12.75 13.00 13.25 13.50 13.75 14.00 14.25 14.50 14.75 15.00 15.25 15.50 15.75 Specific gravity 1.0069 1.0140 1.0211 1.0284 1.0357 1.0375 1.0394 1.0413 1.0432 1.0450 1.0469 1.0488 1.0507 1.0526 1.0545 1.0564 1.0584 1.0603 1.0623 1.0642 1.0662 1.0681 1.0701 1.0721 1.0741 .0761 .0781 .0801 .0821 .0841 .0861 1.0881 1.0902 1.0922 1.0943 1.0964 .0985 .1006 .1027 .1048 .1069 .1090 .1111 .1132 .1154 .1176 .1197 .1219 Percent HCI 1.40 2.82 4.25 5.69 7.15 7.52 7.89 8.26 8.64 9.02 9.40 9.78 10.17 10.55 10.94 11.32 11.71 12.09 12.48 12.87 13.26 13.65 14.04 14.43 14.83 15.22 15.62 16.01 16.41 16.81 17.21 17.61 18.01 18.41 18.82 19.22 19.63 20.04 20.45 20.86 21.27 21.68 22.09 22.50 22.92 23.33 23.75 24.16 Density, "Be1 16.0 16.1 16.2 16.3 16.4 16.5 16.6 16.7 16.8 16.9 17.0 17.1 17.2 17.3 17.4 17.5 17.6 17.7 17.8 17.9 18.0 18.1 18.2 18.3 18.4 18.5 18.6 18.7 18.8 18.9 19.0 19.1 19.2 19.3 19.4 19.5 19.6 19.7 19.8 19.9 20.0 20.1 20.2 20.3 20.4 20.5 20.6 20.7 Specific gravity .1240 .1248 .1256 ,1265 .1274 .1283 .1292 .1301 .1310 .1319 .1328 .1336 .1345 .1354 .1363 .1372 .1381 .1390 .1399 .1408 .1417 .1426 .1435 .1444 .1453 .1462 .1471 .1480 .1489 .1498 ,1508 .1517 .1526 .1535 .1544 .1554 .1563 .1572 .1581 .1590 .1600 .1609 .1619 .1628 .1637 .1647 1:1656 1.1666 Percent HCI 24.57 24.73 24.90 25.06 25.23 25.39 25.56 25.72 25.89 26.05 26.22 26.39 26.56 26.73 26.90 27.07 27.24 27.41 27.58 27.75 27.92 28.09 28.26 28.44 28.61 28.78 28.95 29.13 29.30 29.48 29.65 29.83 30.00 30.18 30.35 30.53 30.71 30.90 31.08 31.27 31.45 31.64 31.82 32.01 32.19 32.38 32.56 32.75 Density, "Be1 20.8 20.9 21.0 21.1 21.2 21.3 21.4 21.5 21.6 21.7 21.8 21.9 22.0 22.1 22.2 22.3 22.4 22.5 22.6 22.7 22.8 22.9 23.0 23.1 23.2 23.3 23.4 23.5 23.6 23.7 23.8 23.9 24.0 24.1 24.2 24.3 24.4 24.5 24.6 24.7 24.8 24.9 25.0 25.1 25.2 25.3 25.4 25.5 Specific gravity 1.1675 1.1684 .1694 .1703 .1713 .1722 .1732 .1741 .1751 .1760 .1770 .1779 .1789 .1798 .1808 .1817 .1827 .1836 .1846 .1856 .1866 .1875 .1885 .1895 .1904 .1914 .1924 .1934 .1944 .1953 .1963 .1973 .1983 1.1993 1.2003 15013 15023 1.2033 1.2043 1.2053 1.2063 1.2073 1.2083 1.2093 1.2103 15114 1.2124 1.2134 Percent HCI 32.93 33.12 33.31 33.50 33.69 33.88 34.07 34.26 34.45 34.64 34.83 35.02 3551 35.40 35.59 35.78 35.97 36.16 36.35 36.54 36.73 36.93 37.14 37.36 37.58 37.80 38.03 38.26 38.49 38.72 38.95 39.18 39.41 39.64 39.86 40.09 40.32 40.55 40.78 41.01 41.24 41.48 41.72 41.99 42.30 42.64 43.01 43.40 Allowance for temperature: 10-15° Be.-1/40° Be or 0.0002 Sp. Gr. for 1° F. 10-22° Be.-1/30° Be or 0.0003 Sp. Gr. for 1° F. 22-25° Be.-1/28° Be1 or 0.00035 Sp. Gr. for 1° F. Originally published as Manufacturing Chemists' Association, Inc. Manual Sheet SD-39. Copies of a similar table giving ° Be1, Sp. Gr. and Tw ° corresponding with percent HCI, are available through the MCA as Manual Sheet T-3. 52 HYDROCHLORIC ACID EMISSIONS ------- VAPOH PRESSURES OF AQUEOUS Miunom OF HYDBOCHLOSIC ACID 0.01 .05 0.1 0.5 1 5 10 SO 100 PARTIAL PRESSURE-HCI, mm Hg 500 1000 Figure C-l. Vapor pressure of hydrochloric acid at various concen- trations. -. 20 3 10 I r ^SPECIFIC GRAVITY 20 30 HCI BY WEIGHT, p.rc.nt Figure C-2. Specific gravity and density versus percent hydrogen chloride. Appendix C 53 ------- ACID BY WEIGHT, p.r«nt figure C-3. Relationship of viscosities of hydrogen chloride and water. a 650 a OF SOLUTION AT 50* C __ INTEGRAL HEAT OF SOLUTION AT IS* C V "*«% BOILING POINT-***^ PARTIAL HEAT OF SOLUTION AT !»• C \ J I I 10 II 20 j I ACID CONCENTRATION, Figure C-4. Heats of solution of hydrogen chloride in water. 54 HYDROCHLORIC ACID EMISSIONS ------- so HCI CONCENTRATION, weight p.rc.nl Figure C-5. Vapor-liquid equilibra for hydrochloric acid. Appendix C 55 ------- 10 IS 20 25 30 35 ACID CONCENTRATION, w.ijt.1 p»rc«nl 45 Figure C-6. Boiling point of hydrochloric acid solution. 56 HYDROCHLORIC ACID EMISSIONS ------- •20 -30 •40 •60 -70 -80 •90 10 20 30 40 50 60 CONCENTRATION, w.ight p.rc.m 70 80 Figure C-7. Freezing point of aqueous hydrogen chloride. Appendix C 57 ------- REFERENCES 1. Statistical Abstracts of the U.S., Bureau of the Census, U.S. Department of Commerce, 1933-1967. 2. Furnas, G.C., Rodgers' Industrial Chemistry, 6th Edition, Volumes I and II, D. Van Nostrant Co., Inc., 1962. 3. Buckley, Joseph A., "Vinyl Chlorides via Direct Chlorination and Osychlorination," Chemical Engineering, November 21, 1966, pp. 102-104. 4. Albright, Lyle F., "Vinyl Chloride Processes," Chemical Engineering, March 27, 1967, pp. 123-130. 5. "Karbate Brand Impervious Graphite Falling Film Type Absorber, Series 31 A," Bulletin N 38-3, National Carbon Company, Division of Union Carbide Corporation, November 6,1961. 6. "Process Design, Haveg Chemical Equipment," Haveg Catalog, Section 7-0, Chemical Equipment Division, Haveg Industries Inc. 7. Kolbe, Von, Dr. E. and Dr. F. Brandmair, "Entwicklugen bei der Adiabatischen Chlorowasserstoff and Fluorwasserstoff Absorption," Chem.-Ingr.-Tech., Volume 35, pp. 262-266, 1963. 8. Gaylord, W.M. and M.A. Miranda, "The Falling-Film Hydrochloric Acid Absorber," Chemical Engineering Progress, Volume 53, No. 3, March 1967, pp. 139-M- 144-M. 9. Standard Methods of Chemical Analysis, 6th Edition, Volume 1, D. Van Nostrand Company, Inc., 1962, pp. 329-330. 10. Caldwefl, I.E. and H.V. Mayer, fnd. Eng. Chen, Anal. Ed., 7, 38, 1935. 11. Jacobs, M.B., The Chemical Analysis of Air Pollutants, Interscience Publishers, Inc., p. 199,1960. 12. Patton, W.E. and J.A. Brink, "New Equipment and Techniques for Sampling Chemical Process Gases,"/. Air Poll. Control Assoe^, 13:162-66, 1963. • 13. Smith, W., et al., "Stack Gas Sampling Improved and Simplified with New Equipment," APCA paper 67-119, Cleveland, Ohio, June 1967. 14. ASTM Standards, Part 23 Industrial Water; Atmospheric Analysis, 1965, pp. 26-28. 15. Perry, J.H., Chemical Engineering Handbook, Volume IV, McGraw-Hill Book Co., New York. 59 * U.S. GOVERNMENT PRINTING OFFICE: 1969 O—3S5-116 ------- |