US1477107A - Method of and apparatus for the manufacture of sulphuric anhydride - Google Patents

Description

Dec; 11, 1923. 1,477,107

C. H. CAREY METHOD OF AND APPARATUS FOR THE MANUFACTURE OF SULPHURIC ANHYDRIDE Filed June 28 1922 Fatented Dec. 11, 1923.

QLAUDE H CAB/EY, OF WILMINGTON, DELAWARE, ASSIGNOR '10 ATLAS POWDER COM- PANY, OF WILMINGTON, DELAWARE. A CQRPORATION OF DELAWARE,

METHOD or AND arrana'rns FOR THE MANUFACTURE or sunrnunrc ANHYDRIDE.

Application filed. June as, 1922. Serial No. 571,489.

T all whom' it may concern:

Be it known that CLAUDE H. CAREY,

in y invention relates to method of and apparatus for the manufacture of sulphuric anhydride or sulphuric acid by which the contact process may be carried out with greatly reduced equipment for unit quan- 16 tity of production and greater efficiency may be attained by providing for the satisfactory conversion of high percentages of SO,

in the gases entering the converter system.

Heretofore contact plants have been oper- 29 ated with percentages of SO below 9% whereas I propose, by my invention, to use as high as 12% S0 from the burningof brimstone in air or 25% from a mixture of 100% S0 gas with air. It is well-known 25 by those who are familiar with the manufacture of sulphuric anhydride that the difficulty of operating with a high percentage of SO in the gases is the intense heat generated b the. reacting gases in the converters whic 1prevents the reaction from going to comp etion and causes severe wear on the apparatus. It has been the usual practice to use preheaters in advance of the converters and to provide for the elimination of the heat of reaction by various means, such as radiation from the converter shells or intercoolers'between the sections of the contact material, which involves the use of a heavy investment in equipment and of complicated apparatus with greatly increased cost both from the.

standpoint of initial installation and of maintainence and operation.

This invention not only allows a very high percentage of SO to be carried in the gas entering the converter system but requires a much smaller investment in equipment as will be seen from the accompany-v ing diagrammaticdrawing, wherein 5 is the main supply pipe to the converter for cool or partially heated sulphurous acid gas. By

means of a bypass 6 and dampers 30 and 31. of the converter system the incoming gas may be permitted to directly pass into supply pipe 5 or may be delivered to said pipe nhydride, of which the follow connected to the upper part of the second from a heat exchanger 7 or may be divided between the two. The pipe 5 is in communication through a T 8 with a fan casing, 9, the fan receiving its supply from the T; 8 and discharging through an outlet 10 into the contact compartment 11 of" the converter A.- The contactcompartment 11 is located within a space formed by the walls 12 and- 13 which lie in spaced relation to the, main wall 14 of the contact chamber, so. that"a space 15 is left between thesewwall s' .yvhich space at. the'top is in communicationwith the contact compartment and at fthe bottom is an communication with' a flue leading to the T 8. A valve or damper .17 is locatedin the flue 16 for a purpose hereinafter set forth. A shell 18 surrounds the wall 14 of the converter, the space 19 within this shell being in communication with a furnace 20, through a .fiue 21, A waste heat stack 22 leads from the upper part of the space 19, and flue 21 and stack 22 areprovided with controlling dampers 23 and 24, respectively. The upper part of the first converter A is U0 converter. B by means of a flue 25. .The dischargefrom. the second converter B into the heat exchanger? is through a flue 26 and the ,discharge of the gasses from the heat exchanger is through a pipe 27.

In starting a. converter system it is necessary to bring the catal zer up to a suitable reacting temperature. t is the usual prac 1 ties to accomplish this by passing hot gases previously heated in a preheater through-the contact chambers. The present process differs from the foregoing by passing the preheating gases from a furnace directly to the converter shell through the space'19. By recirculating the gases repeatedly through the annular space 15, flue 16, T 8 and flue 10 by means of the blower or fan 9 the whole apparatus is brought up to the desired temperature without passing any gas through the complete converter system. This is especially advantageous when the contact plant has been shut down for a short period and the temperatures in the contact chambers have dropped to a point unsatisfactory for starting conversion. 108 With this type of apparatus the temperatures may be increased to the conversion point in contact chamber 11 without losing a high percentage of SO, outof the exit stack. Converter B may be brought up to 110 the desired temperature by gases from convert er A in which the major ortion of the SO, has been converted to S It will be recognized by those familiar with the .art of manufacturing sulphuric acid b the contact process that this method of preheating the contact chambers to the proper temperatures is more efiicient and requires a much smaller investment in equipment than the methods heretofore practiced. It should be understood that I do not limit the heating of the converter shell to furnace gases as any other suitable means may be employed for thisvpurpose. The contact material to beused in the contact chambers of the converters A and B may be platenized magnesium sulphate as described in U. S. Patents 636,924 and 636,925, although I do wish to limit myself to this material, or the percentages of platinum contained therein. The contact material 28 may be distributed in one layer or more, being supported on suitable screens 29. The fan to be used for recirculating the gases may be of any standard design used for moving hot gases, or other suitable mechanism may serve the same purpose. It is desirable to conserve as much heat of the reaction in the converter A and blower equipment, as possible, by covering the preheating shell and blower connections with some non-heat conducting material. keep the heat radiation from flue 25 and converter B down to the minimum as the gases passing fromconverter A to B may be at a temperature slightly higher than desired for entering and passing through I the contact mass in converter B.

In operation, after the temperature of the converter chamber A has been brought up to the desired point, cool,'sulphurous acid gas or gas partially heated by passing through the heat exchanger 7 passes into T 8 where hot gases, in which the major portion of the S0 has been converted into 801 are met coming from contact chamber 11 through the space 15 and flue 16. These combined gases pass into the inlet of fan 9 and are forced through flue 10 into contact compartment 11. An approximately equal quantity of gas to that flowing through pipe 5 passes out of the contact chamber into the inlet of converter B through flue 25, where the final maximum conversion is obtained. The excess heat of the gases may be removed by passing thev It is not essential to sired percentage of SO enteringthe contact material may be obtained thereby preventing an appreciable rise in temperature.

This will cause a high percentage of conversion' to take place. I have found that be, tween 790 and 930 F. the rate of conversion is very rapid and nearly complete for S0 gas concentrations which correspond to an initial SO content under 13.3% for a gas derived from burning brimstone in air and 28% from mixing 100% S0 gas wlth alr. Enough of the gases are therefore returned from converter A, after passing through the.

contact mass, to keep the S0 content of the total mixture passing into the contact mass, such that the temperature rise will not exceed 930 F. While the percentage of SO, in the gas from pipe 5 is being, reduced the gas at the same time is being brought up to the reaction temperature of 790 F. A twofold result is, therefore, secured by this method of operating. As a result of the conservation of heat in the converterA andits connections, only a small amount of insulating material is needed between the outlet of converter A and the contact material in converter B in order to permit the gases to enter the latter at a satisfactory temperature for conversion.

It is well known that the last 5% to 8% of the total conversion is obtained with difficulty and it is therefore necessary to bring the gas mixtures in contact with the catalyzer at the most favorable temperature in converter B. As a result of the major part of the S0 having been converted into SO,

contact chambers.

It will be appreciated by those familiar with manufacturing sulphuric acid by the contact process one commercial scale that the entire plant investment is decreased by operating with a high percentage of sulphurous acid gas in the system. A high percentage of S0 is desired in the gas when the plant is manufacturing fuming acid, as the amount of SO absorbed depends on the amount of SO in the gas, other conditions being equal.

It must not be understood that I limit my invention to mixtures of sulphurous acid gas and air as this process would also be applicable to a mixture of sulphurous acid gas and oxygen. I

It is the purpose of my invention to reduce the cost-of manufacturing sulphuric acid by the contact process by reducing the size of the converter equipment and regulating the temperatures therein so that cxcessiyo wear on the apparatus is prevented, maximum efiiciency is obtained from the contact material, and a high percentage of sulphur bearing as is carried through the entire contact p ant system, this reducing the plant investment. I

Having described my invention what I claimis:

1. In apparatus for the manufacture of sulphuric anhydride by the cont-act process, a converter comprising a contact compartment, a supply conduit for conducting gases to be converted thereto and means for conducting a part of the gases of conversion from said compartment to said supply conduit.

2. In apparatus for the manufacture of sulphuric anhydride by the contact process, a converter comprising a contact compartment, a supply conduit for conducting gases to be converted thereto and means for conducting a part ofthe gases of conversion from said compartment to said supply conduit and means for controlling the extent of dilution of the incoming gases by said gases of conversion. V

3. An apparatus for the manufacture of sulphuric anhydride by the contact process comprising two connected contact chambers, a supply conduit for-conducting SO to the first contact chamber for conversion and means for conducting a portion of the gases of conversion from the first contact chamber to said supply conduit the remainder of the gases of conversion'passing from the first contact chamber to the second contact chamber where conversion is completed.

4. A. structure as recited in cla1m'3 1n combination with means for controlling the 6. An improvement in the art of manu facturing sulphuric anhydride by the contact process which consists in introducing a diluting gas from the outlet of a converter containing catalytic materialto the sulphurous acid gas and air mixture entering the converter, thereby reducing the concentration of the reacting gases entering the contact mass.

7. An improvement in the art of manufacturing sulphuric anhydride by the contact process which consists in transferrin only a portion of the gases passing through one contact chamber into a second contact chamber, the remainder of the gases reentering the first chamber.

8. An improvement in the art of manufacturing sulphuric anhydride by the contact process which consists of conducting gases to be converted to a contact chamber and carrying a part of the gases of conversion from said contact chamber from an outlet'thereof back to and introducing them into the stream of incoming gas.

9. An improvement in the art of manufacturing'sulphuric anhydride by the contact process WlllCh consists of conducting gases to be converted to a contact chamber and carrying a part of the gases of conversion from said contact chamber from an outlet thereof back to and introducing them into the stream of incoming gas in such amount as to prevent a rise of temperature above 930 F. in the contact chamber.

10. An improvement in the art of manufactoring sulphuric anhydride by the contact process which consists of conducting gases to be converted to a contact chamber and carrying a part of the gases of conversion from said contact chamber from an outlet thereof back to and introducing them into the stream of incoming gas in such amount asto maintain the temperature in CLAUDE n. CAREY. 1

Witnesses ISAAC Foes, EMMA COLLINS.

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