USRE15314E - Island - Google Patents

Description

UNITED STATES PATENT OFFICE.

ADRIAAN NAGELVOORT, OF PROVIDENCE, 'RHODE ISLAND, ASSIGNOR TO THE NITRO- GEN CORPORATION OF PROVIDENCE, RHODE ISLAND, A CORPORATION OF RHODE ISLAND.

METHOD or rno-noomo son'rom BICARBONATE AND mmauum.

Specification of Reissued Letters Patent. Reissue-d lvlar, 21, 1922,

No Drawing. Original No. 1,352,211, dated September 7, 1920, Serial No. 357,042, med February 7, 1920. Application for reissue filed July 16, 1921. SeriaLNo. 485,287.

To all whom it may concern:

Be 1t known that I, ADRIAAN NAoELvooRT,

'a citizen of the United States, residing at Providence, in the county of Providence and State of Rhode Island, have invented certain new and useful Improvements in Methods of Producing Sodium Bicarbonate and Hydrogen, of which the following is a specification.

This invention, in one of its aspects, relates to the ammonia soda process, and in another of its aspects, to the production of substantially pure or readily purifiable gas or gaseous mixtures, suitable for use in the synthesis of ammonia, from its elements.

In the ammonia soda process, for the production of sodium bicarbonate and carbonate of sodium, the following reaction is utilized:

The CO, gas for producing the above're action is obtained from the burning of limestone in special lime kilns; in which case the CO gas is mixed with nitrogen,the mixed gases having approximately the fol-- lowing analysis:

00., 435% to 407;. N2 65 /(7 to The Solvay towers were designed for the use of a carbonating gas containing approxima'tel 50% ()0 and 50% N and since their introduction by Solvay, they appear not to have been materially improved upon. In practice, a gas thus containing approximately 50% CO and 50% N has been found to be most suitable in the manufacture of bicarbonate of soda; because with such a mixture of gases, crystals of the bicarbonate salt have been found to form with ideal fineness, size, texture, etc.

I have discovered that hydrogen may be substituted for nitrogen as a dilutent of the carbon dioxid, without impairment to theproeess in any way; while on the other hand certain very important advantages are obtained by this substitution.

To begin with, this discovery enables me to entirely eliminate, if desired, the quite costly step of burning limestone to produce tin-( 1.required for the ammonia soda process. One reason why this step is comparatively costly, is the great expense of installation and upkeep of the kilns in which the lime is burned; together, of course, with the cost of mining the stone.

A second great advantage resides in the fact that the operation set'forth in equation (1), which has heretofore been conducted solely for the purpose of producing sodium bicarbonate; may, by effecting the herein described modification thereto, be caused to act in a dual capacity and yield not alone sodium bicarbonate, but also substantially pure hydrogen.

The foregoing may be accomplished, desirably, by using water gas as a source of the C(),,which becomes possible by virtue of my aforesaid discovery. \Vater gas. may be considered as having approximately the following analysis:

I1 49; CO, 40%; G(). 5%; N 5%; II S, and about of (3H,, or the like, etc.

To obtain hydrogen gas from such a gaseous mixture, it hasheretofore been necessary to remove the other gases eitherby ll'}lll(liltl()ll 0l absorption by suitable absorbers, with or without pressure.

B converting the CO in the water gas,

- into CO and H, by-means, for example, of

some one of the known metal-oxid catalytic masses,mixin steam with the water gas preparatory to of ecting contact of the so formed, gaseous mixture with the contact body,-it is possible to obtain a mixture of hydrogen and carbon dioxid, associated" with varying amounts of carbon monoxid and nitrogen, and In somecascs, with other nnpurltu-s such as hydrogen sulfid; care being taken in the contact prbcess, to avoid methane or like hydrocarbon formation dun ing the steam treatment.

The percentage of CO in this mixture may be made quite small"; the amount, of course, dqmnding upon the-nature of the catalyst and the temperature of the operation.

Such a small percentage of CO and other impurities, in the gases emerging from the contact chamber, will not be harmful in the manufacture of bicarbonate of sodium in ammonia soda process. Accordingly, I now cause the said mixture to pass up through usual a Solvay carbonating tower, in lieu of the mixture of carbon dioxid and nitrogen.

TheCO content of the gaseous mixture is separated by the sodium bicarbonate forming reaction and nearly pure hydrogen passes off at the top of the carbonatirg tower.

The remaining tracesof CO 'in this exit gas may be eliminated by known treatment, such as by using cuprous .chlorid solution as an absorbent for the CO.

As will be hereinafter pointed out, the

sulfur bearing gaseous impurities may be automatically eliminated in the Solvay towers, and, hence, the gas obtained is substantially pure hydrogen containing .more or less nitrogen, which is -unobjectionable; since a mixtur'e'of three parts by volume of nitrogen, to one of hydrogen, must be provided for the ammonia synthesisoperation.

I may enrich my mixture of hydrogen and carbon dioxid gases, obtained from the water gas, by addingthereto pure CO from the calcining furnaces in which the bicarbonate of sodium is converted into sodium.

carbonate-An which operation CO and H 0 are produced; the H 0 being separated from the CO by suitable condensers. pref erably before said carbon dioxid is thus added to the hydrogen-carbon-dioxid mixture. a

I shall 'now consider the third great advantage of the present improvement in the ammonia soda process. usually conducted, a small amount of sulfur is regularly introduced into the carbonating towers in the form of H S or (NTL). ,S to form a coating of Fes on the interior walls of these carbonating towers, which are made of iron.

This prevents the corrosion of the iron walls. and keeps the precipitated bicarbonate free from iron rust, which, otherwise would color and spot and make unsalaliile the sodium bicarbonate.

In water gas there is always more or less H S which, especially if'present in any material amount, should be removed before the (X) of the water gas can be elliciently eonrerted into CO by the catalyst or catalysts used as contact bodies to'eil'ect the reaction:

In order to prolong the life of the C0 and Ill forming catalyst, l'have found it of advantage to'lirst pass the water gas directly througlione or more Solvay carbonatiug towers to eliminate the hydrogen sulfid and the CO incidentto the production of the water gas hefore passing the exit gases through the contactapparatus for conversion of the CD into (fo The S content of the water gas isjust about enough to keeptheeai'lmnating towers In said process,

coated with FeS, for the step of the operation in which the CO is utilized in the formation of sodium bicarbonate. When said H 8 content is insufficient for this purpose, a small quantityof H S can be added directly to the water gas. In general, the

amount of sulfur initially present in the water gas depends, used for making said gas.

The preferred mode of conducting the entire operation is hence briefly as follows:

I'bubble the water gas coming from the generators, up through ammonia brine solution in one or more carbonating towers of of course,

upon the fuel a an ammonia soda process plant,-to remove sulfur compounds together with any CO present in said gas,-then take the gases from said tower or towers, which are now substantially C0 and H and add steam preparatory to passing the mixture, at an elevated temperature, over a heated catalyst. to convert all CO into"CO by'the reaction expressed b equation (2). #Fiirallyg'l pass the prefera ly so produced mixture (if CO and H through the ammonia brine solution in a second carbonating tower, or series of towers, for the precipitation of sodium bi carbonate and simultaneous purification of hydrogen gas for use in the synthesis of ammonia, the hydrogen content of the Illikllll'l.

I passed through this second tower. preferably utilizing the hydrogen gas thus freed from the carbon dioxid in the production of ammonia and utilizing the reaction with amnioniated brine for the double purpose of forming sodium bicarbonate and effecting a preliminary purification of the hydrogen gas to adapt the same for use in the synthesis of ammonia.

By using each carbonating tower of an ammonia soda plant in turn, for the removal of sulfur compounds from water gas, hlkeep the interior of my towerscoated with ms.

Having thus described my inventiomyvhat I claim 15:

1. The improvement in the etfectuation of the ammonia soda process which comprises.

reacting upon ammoniated brine with carbon dioxid diluted with hydrogen to prevent undue development of heat and favor the formation of relatively large crystals of sodium bicarbonate, while simultaneously separatlng said carbon dioxld from said hydrogen, and collecting said hydrogen "preparatory to using the same in an ammonia synthesizing operation.

2. The improvement in the efl'ectuation of the ammonia soda process which comprises reacting upon ammoniated brine with car bon dioxid diluted with hydrogen and which mixture of carbon dioxid and hydrogen is substantially free from carbon monoxid, to simultaneously produce sodium bicarbonate and hydrogen substantially free from gaseous impurities other than nitrogen.

3. The process of producing sodium'b carb'onate and hydrogen, which comprises treating a. gaseous mixture containing carbon monoxid, carbon dioxid. hydrogen and hydrogen sulfid, to free said mixture from said dioxid and sultid, by bubbling it through ammoniated brine in a receptacle the walls of which are of iron. treating the exit gases to convert said carbon monoxid into carbon dioxid, and bubbling the gaseous residues through amnioniated brine to produce sodium bicarbonate and hydrogen.

4. The improvement in the etl'ectuatiim oi" the ammonia. soda process which comprises treating carbonaceous matter, at an elevated temperature, with steam, to form carbon dioxid and hydrogen, and separating said hydrogen from said carbon dioxid through the intermediary of ammoniated brine.

The improvement in the efi'ectuation of: the annnonia soda process, as conducted in carbonating towers the walls of which are of iron, which comprises converting the surfaces of said walls into iron sullid. to providejt'oatings of said sullid upon said walls, v-; assing through said towers the gaseous reaction products resulting from the conversion of sulfur bearing fuel and steam.

into hydrogen. hydrogen sullid. carbon monoxid and arbon dioxid. treating the gases e 'rging lrom said-tower to convert said "I c rbon inonoxld into carbon (bond, and

separating said carbon dioxid from said hydrogen by reacting upon said dioxid with ammoniated brine in a carbonating tower the walls of which are coated with iron sulfid to prevent discoloration of the sodium bicarbonate crystals formed by said last mentioned reaction. a

G. The improvement in the etfectuation of the ammonia soda process, as conducted in carbonating towers the walls of which are of iron, which comprises converting the surfaces of said walls into iron sulfid, to provide coatings of said sultid upon said walls, by passing through said towers the gaseous reaction products resulting from the conversion of sulfur bearing fuel and steam, into hydrogen, hydrogen suliid, carbon monoxid and carbon dioxid.

7. The process of producing sodium bicarbonate and synthetic annnonia by interrelated operations which comprises the formation of a gaseous mixture and the utilization of said mixture to effect the first of said operations and at the same time eliminate from said mixture gases which are adapted to injurious'ly affect the second operation.

8. lhe 'n'ocess oi producing sodium birarbonate and an'nnonia which comprises the formation o'l" a gaseous mixture including carbon dioxid and an ammonia forming gas, utilizing said mixture. in the production of sodium bicarbonate whereby said ammonia forming gas serves as a dilutent tor the carbon dioxid. and recovering the ammonia forinin gas thus freed from carbon dioXid.

9. The process of obtaining pure or substantially pure hydrogen by reacting upon ammoniated brine with a mixture of carbon dioxid and hydrogen. I

In testimony whereof I have atiixed my signature.

ADRIAAN N AGIGIJVOUK-T.