1038
T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING C H E M I S T R Y
tilization of potash t h a t normally prevailed a t t h e plant of t h e Security Cement and Lime Company, but below t h e 6j per cent volatilization t h a t has now been secured a t this plant. If it be assumed t h a t t h e last-mentioned percentage volatilization could be attained by chemical or other means in all plants where a lower volatilization normally prevails, then it may be estimated t h a t t h e recoverable available potash in t h e cement plants of this country would be increased from 67,000 tons t o about I O O , O O O tons annually. This estimate represents a recovery according t o our analyses of only between jo a n d jj per cent of t h e total potash entering t h e kilns in t h e different plants. At t h e plant of t h e Security Cement a n d Lime Company, where no steps are yet taken t o make soluble t h e slowly soluble potash, the percentage of available potash recovered is somewhat less t h a n this, b u t a t t h e plant of t h e Riverside Portland Cement Company t h e recovery of soluble potash is already considerably greater. Improvements over present methods of recovering potash are t o be expected a n d it would therefore seem t h a t an estimated possible average recovery of about 50 per cent should not be considered excessive. Whether or not this percentage can be economically recovered in all plants remains t o be determined. I t may also be pointed out t h a t t h e weight t h a t can be attached t o these estimates is also dependent on t h e representative character of t h e samples analyzed. Analyses of a number of samples corresponding t o those which we have analyzed, but collected from six t o nine months previous t o t h e time our samples were taken, have also been made by other chemists and particularly by t h e Western Precipitation Company. I n every case in which t h e results were compared there was found t o be a n agreement within t h e limits of experimental error. It is, of course, recognized t h a t t h e analysis of further samples collected from some other plants might not show the same close agreement, b u t from t h e observations which have been made it is thought t h a t as a whole t h e results obtained are representative. C O L L E C T I O N O F C E M E N T FLUE DUST
Cement flue dust is now being collected by t h e Cottrell process of electrical precipitation a t t h e plants of t h e Riverside Portland Cement Company and t h e Security Cement and Lime Company; a t several plants of t h e Universal Portland Cement Company; a n d a t t h e Cementon Plant of t h e Alpha Portland Cement Company, At t h e Riverside plant the dust is being used for t h e preparation of concentrated potash salts, while a t t h e Security and Cementon plants it is disposed of directly for use as a fertilizer. T h e dust from t h e Universal plants, being too low grade t o serve as a source of potash, is simply returned t o t h e kilns for manufacture into cement. Installations of t h e Cottrell process are now being considered b y a number of other cement companies and operations have already been started on t h e installations a t t h e Coplay, Dexter and Ironton Portland Cement plants, a n d a t t h e plant of t h e Buffalo Potash a n d Cement Corporation, where a commercial installation
Vol. 9, No.
II
has been erected for t h e recovery of potash from feldspar by use of t h e latter in t h e manufacture of cement. Wet processes for precipitating cement dust are now in operation or are being installed for one or more kilns a t t h e plants of t h e California Portland Cement Company, t h e Santa Cruz Portland Cement Company, and t h e Sandusky Cement Company. SUMMARY
The constituents of t h e dust in all cement plants are much t h e same b u t may vary greatly in relative proportion. I n t h e case of freshly precipitated dust collected in t h e normal operation of a cement plant t h e soluble constituents consist for t h e most part of t h e sulfates, chlorides, sulfides and polysulfides of potash, soda and lime. Chlorides occur only in small amount. The percentages of sulfides and polysulfides in t h e dust from different plants may vary widely and in t h e case of dust from some oil- or gas-fired plants may be entirely absent. Free lime is found in all cement dust, and in t h e water extract of all samples analyzed, t h e basic radicles were found t o be in excess. I t follows, therefore, t h a t t h e potash in t h e water extract of freshly collected flue dust will be present t o a greater or less extent in t h e form of t h e hydroxide. As t h e dust becomes carbonated, either by chemical treatment or by exposure t o t h e air, t h e hydroxides present will change t o carbonates, and by interaction of t h e carbonates with calcium sulfate in t h e dust t h e water-soluble potash will be obtained principally in t h e form of t h e sulfate which is t h e form universally recognized as of most value for use as a fertilizer. BUREAUOF S O I L S
U.S. DEPARTMENT OF AGRICULTURE WASHINGTON, D.
c.
SOLVENT GASOLINE' By C. OLIN NORTH Received July 2, 1917
The sudden jump in t h e price of gasoline last year was of prime importance t o t h e automobile owner, b u t if anything it affected t h e rubber companies more. Because of their high cost, gasoline had replaced t o a great extent all other solvents for use in rubber cements and doughs. A small rubber factory making I 500 tires a day will use approximately 12,000 gals. per month, while a large company will require close t o IO,OOO gals. per day. I n 1 9 1 j a good grade of solvent gasoline could be procured a t 1 5 t o 18 cents per gal., but in 1916 i t jumped t o 2 6 t o 30 cents per gal. Solvent gasoline is customarily of j o t o 7 2 " BC. gravity, though for certain purposes 80' BC. is required. It must be readily volatile and must be free from kerosene tails. A comparison of its rate of evaporation with those of some common solvents is as follows, when z cc. of each liquid were allowed t o evaporate from a metal surface 3 1 / 2 in. square, under similar conditions: Benzol (90%) ..... 14 min. Solvent Gasoline: SOo BC. ... .4min. Commerclal N a p h t h a , ,107 min. 7O0 BC... . .8 min. Turpentine. ,142 min. Toluol. . . , , , . .33 min. Distillation tests on representative samples of the three grades of gasoline, v i z . , Motor, Solvent, and Paint & Varnish Makers' Naphtha, resulted as follows: 1 Submitted as partial fulfillment of t h e requirements for the degree of Chemical Engineer, Carnegie Institute of Technology, Pittsburgh, Pa.
Nov., 1917
T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING C H E M I S T R Y
.............. ... ... . ....... .. .. ... ....... ....... . . ... ....... . . 45 % distills below. ....... ... 50% distills below.. ....... . . 55 distills below. ........ . . 60 distills below.. ......... 65 distills below.. , , . , . . ... 70 distills below.. ...... ... 75 ' distills below. .......... 80 ' distills below.. ....... . . 85 ' distills below.. ...... ... 9 O g distills below. ....... Sp. gr. at 1 5 O C Gravity. ................ Distillation began.. . . . . . . 5 % distills below. ....... 10% distills below.. 15% distills below.. ...... 20% distills below ... 25 yo distills below. ....... distills below.. ... distills below.. ......
f
......
distills below.. 595$ lost during distillation
...
Motor Naphtha 0:716 65.5'BC. 450 77.5 a5 91 96.5 99 102 105.5 108 111 116 120.5 121 127 131.5 138 144 154 161.5 177
c.
.
Solvent Paint & Varnish Naphtha Makers' Naphtha 0.697 0.746 70.9' Be. 57.7OBe. 123O C. 46' C. 64 133 69 136 138 73 141 76 143 79 144 a2 144 85 145 88 148 90 149 94 150 97 152 100 153 102 156 106 158 111 163 116 166 121 174 125 180 137
1039
PRESSURE-The chief service of pressure is t o produce saturated hydrocarbons. Heat breaks u p t h e oil into saturated a n d unsaturated bodies, while pressure tends t o increase t h e saturated a t t h e expense of t h e unsaturated. Unsaturated Hydrocarbons )r Saturated Hydrocarbons. Diminished pressure increases decomposition, b u t increased pressure works t h e other way. For example, diminished pressure favors t h e production of gas, while increased pressure aids in t h e formation of gasoline. CONCENTRATION-The gases produced during cracking may be classed as condensable or non-condensable. I n t h e first class may be placed gases condensing a t , say, from 20' C. up (gasoline), a n d in t h e second such ones as hydrogen, methane, etc., which do not condense until very far below 2 0 ' C. These may be called fixed gases. It is quite in accordance with t h e law of mass action t h a t t h e withdrawal, i. e., condensation of t h e condensable gases in t h e presence of t h e non-condensable, favors t h e formation of t h e condensable hydrocarbons. Therefore condensation should be effected
The experiments described below were performed a t t h e chemical laboratory of t h e Republic Rubber Company, of Youngstown, Ohio, in t h e years 1915-1916, a n d were undertaken with a view t o securing a good grade of solvent gasoline a t a reasonable price b y cracking heavy kerosene or other heavy oil. The method and apparatus finally developed cannot, in a strict sense of t h e word, be called original, since features were contained which m?ght rightly be considered a n infringement on certain well-known patents. However, t h e development took place in logical steps a n d I feel t h a t t h e work was of value in t h a t I attempted t o embody in m y procedure such points as I considered of prime importance in other processes, a n d t o improve on t h e m t o t h e best of m y ability. As in the Burton process, t h e pressure within t h e apparatus was built u p b y heating a comparatively large volume of oil. I n common with t h e R i t t m a n process t h e cracking was accomplished in t h e gas phase. Condensation was effected under pressure a n d in t h e presence of t h e non-condensable gaseous products of t h e reaction. THEORETICAL coiisIDEunoNs-In comparison with t h e benzene-toluene process, t h e production of gasoline is comparatively easy. Rittmanl considers t h e order under pressure and in t h e presence of t h e non-conof hydrocarbon formation t o be as follows: densable gaseous products of t h e cracking reaction. Heavy Petroleum Hydrocarbons Light Petroleum DURATIOY-The time factor is intimately related t o Hydrocarbons (saturated a n d unsaturated) J_ t h e temperature a n d pressure employed. Thus a higher Cymene )r Xylene Toluene )r Benzene )r temperature requires a shorter time for equilibrium t o Naphthalene, Diphenyl, etc. Anthracene be established. It may also be regulated by Carbon and Gas. I-Varying t h e length of t h e cracker, I t is evident t h a t t h e production of gasoline requires a-Introducing a catalyzer, , but one step. 3-Changing t h e rate of oil supply. T h e factors influencing a n y reaction in t h e vapor I n R i t t m a n ' s process this is accomplished by varying phase are: ( I ) Temperature, (2) Pressure, (3) Con- t h e feed. But with my apparatus i t was effected b y centration, (4) Duration. regulating t h e fires under t h e kettle. I also found i t TEMPERATURE-since all organic substances decom- advantageous t o fill t h e cracker tube about threepose on application of heat, it is self-evident t h a t t h e quarters full of 2 in. x I in. pieces of sheet metal bent higher t h e temperature t h e greater t h e degree of de- t o a right angle. These served t o prolong t h e sojourn composition. Heavy molecules are more unstable t h a n of t h e gases in t h e cracking zone. lighter ones of similar structure. This fact must be APPARATUS considered in making t h e proper choice of cracking T h e apparatus was of necessity very simple, a n d temperature. Any oil or kerosene heavier t h a n gasoline can be used as a raw material for t h e production of only such parts were contained as might be found in gasoline if t h e correct cracking conditions are observed, a n y well-ordered pipe or tin shop. KETTLE-The original kettle was a small dental T H I S JOURNAL. 8 (1916). 351. Also Bureau of Mines, Bulletin autoclave of one liter capacity. The volume of oil 114; Met. &" Chem. Eng., March 1 , 1916.
1040
T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING CHEMISTRY
contained proved t o be entirely insufficient t o get up proper pressure within t h e apparatus. For t h e next trial a 12-in. piece of double extra heavy wrought-iron pipe, 6 in. diameter, was capped a t both ends, b u t beCause of poor threading t h e outfit leaked like a sieve when heated up, a n d was discarded. Consequently it was decided t o oxyacetylene weld the heads into t h e pipe, and a very satisfactory kettle was secured in this manner from a 1 2 in. section of double extra heavy wrought iron pipe 6 in, in diameter. The capacity of this kettle was 340 cu. in,, or 1.47 gal., amounting t o 5 5 5 0 cc. This allowed t h e use of a comparatively large quantity of oil, and insured a wider range of pressure. The kettle was carried by a n angle iron s t a n d built in such a way as t o support t h e fire brick which surrounded it. A burner rack carrying t h e blast lamps was placed a t proper height underneath. The fuel used was natural gas. The whole was encased in fire brick arranged so t h a t the flame from the burners on its way t o the stack
Vol. 9 , No.
11
only in t h e kettle but in t h e cracking zone and reflux condenser as well. (3) A 3/s-in. pipe fitted with a globe valve was placed as low down as possible on t h e end of the kettle, which was tilted slightly so as t o allow almost complete draining. (4) Connection was made with the cracker through a 38-in. length of l/Z-in. heavy, wrought-iron pipe. This was broken 1 2 in. from t h e top a t a union, below which was placed a gate valve. The fillin5 pipe, which also had a gate valve, was teed into t h e riser pipe 8 in. above the center of t h e kettle. The fill pipe was arranged in such a way t h a t i t could have been easily connected t o a pump, which would have made t h e apparatus suitable for continuous running. CRACKER-The cracking tube consisted of a 39-in piece of double, extra heavy, wrought-iron pipe, 2 in. in diameter, plugged and tapped a t both ends. A plugged tee was placed on t h e end next the kettle for t h e removal of any carbon. A 30-in. section of t h e tube was encased in fire .b
.A
