Process of production of hydrogen.
AS AFRICAN AND MALAGASY INDUSTRIAL PROPERTY P. 887 Yaounde (Cameroon) Patent International Patent Classification: 01 - c10 no. 01390 C. the O. 00 the m ^ P.I.. 31 December 1964 to 18 hr 36 requested Mn to the O.A.M.P. I-. (G.P. no. 51,845) by Franchise Harper for Marshall, resident to the United States of America. Delivered 4 July 1969, published at The present invention relates to a method to per - fectionné for the industrial production of hydrogen by regenerating catalytic hydrocarbon with water vapor. The conventional process for the production of hydrogen industrial generally comprises the phases suivan - a TES: water vapor pressures within the range 7 to 10.5 kg/cm in the2 relative pressure; transient of the product from the regeneration PRP - mayor to transform most of the oxide carbon dioxide; extracting a C. COEXTRUDEDhas contained in the crude hydrogen, in finally, except baduk contained in hydrogen by the action of the methane or by the absorption liquor cupric upon - the hydrogenation procedure that is responsive to the pre - or against carbon monoxide. During the phase of regeneration made according to this conventional method, more about 90 hydrogen. The improved process according to the invention for the producing hydrogen comprises operating the shift catalytic hydrocarbon such as methane, the pentane or heavier hydrocarbons, using water vapor pressures particularly high, on the order of about 50 kg/cm from 21 to2 in near - absolute SiON film, this range preferably lying between 24 and 42 kg/cm.2 in absolute pressure, resulting in a degree of conversion of these unusually low hydrocarbons, is in the range of about 50% to about 85%, this percentage being preferably between 60 and 75%, giving hydrogen whose quality is abnormally YR - ment and containing up to 7.5 to 14% of hydrocar - robe then unconverted if operating within the preferred range conversion. In order to make this hydrogen lower grade specific to a signi - industrial ina, the method according to the invention uses during the process of producing a phase control loop is - food System which was unnecessary to date. This phase complementary is a cryogenic separation between hydrogen and hydrocarbon, in order to increase the hydrogen concentration until it reaches 97.5 to 99 unexpected that this partial conversion of the hydrocarbon feed, combined with a cryogenic separation, appreciable economic advantages are obtained compared to the conventional method of hydrogen production. On the single fig. of the attached drawing is shown very schematically the relative arrangement of circuits and apparatus for implementing the method according to the invention. In short, this method is carried out as follows: Figure, the hydrocarbon feed is subjected in the regenerator R L to a catalyst regeneration using steam, while in the converter product from the human c-L-R-L is treated to convert said carbon dioxide most of the carbon monoxide produced in the regenerator. After condensation of the water vapor contained in the product from c-I, the condensate is separated in the separators S-L and s 2 and the extracted carbon dioxide. Extracting the carbon monoxide can be by any means known; therefore, it has not been shown on the drawing. The excess hydrocarbon is separated from the crude hydrogen gas by cryogenic, according to a known method, as shown schematically in the drawing. Other details of the method of the invention shall become apparent from the exemplary implementation of this method, which will be discussed further below. Was constructed in all parts of the world many facilities for the production of hydrogen, which use the fundamental phase catalyst regeneration hydrocarbons with water vapor at elevated temperatures. Most operate under conditions intended to ensure on the one hand a very high rate of hydrocarbon conversion during the regeneration phase, this rate exceeding 90 For example, during a hydrogenation step, such that the hydrogenation under high pressure carbon-containing products, the presence of an inert gas, such as methane, with hydrogen, substantially affects the efficiency of the operation. In many operations hydrogenation it is customary to maintain a concentration of about 90% of hydrogen in the gas phase. Under these conditions, the purging of a single volume of inert hydrocarbon introduced by the feed gas stream requires the simultaneous purging and loss, in the circuit, of nine volumes of hydrogen, expected that each mole of methane purged takes with it nine moles of hydrogen. It is well known that the regeneration hydrocarbon pressures is offers some advantages of economy, expected that the requirements with regard to the gas compression are even reduced and obtained a higher rate of recovery of calories. Furthermore, it is also known that the use of high pressures delays hydrocarbon conversion. Thus, for example, the dominant reaction typically may be expressed thus: ^ HC + hr, the O=>coextruded + 3:00 -2 . Based on this equation, the effects due to mass action are such (IEP the delay brought out the reaction is proportional to the square of the absolute pressure in the system. Therefore, the design of a hydrogen production facility constitutes a compromise between the particular advantages resulting from the use of high pressures, on the one hand, and the disadvantage of a lower hydrocarbon conversion resulting, on the other hand. In current industrial practice, hydrogen is produced at a relative pressure of the order of 9 kg/cm.2 or below, and the degree of conversion of the hydrocarbon is about 90% or more. It had results from the direct production, after purification of the crude hydrogen and methanation of carbon monoxide, hydrogen having a purity of 96% reaches, or even more. In some installations for producing synthetic gaseous ammonia is adopted that higher pressures, which is well known to those skilled in, but in such processes, the introduction of air into a secondary phase of regeneration determines a temperature rise which compensates the retarding effect produced by the pressure. Therefore, the improved process according to the invention is limited to catalyst regeneration of hydrocarbons by use of steam only, and it does not have general application in the production of hydrogen where, as in the case of the production of ammonia synthesis gas, other compensation factors are involved. It has been recognized, unexpectedly, it was possible to obtain a superior process of hydrocarbons by catalytic regeneration steam by fulfilling the following conditions: 1° the regeneration process takes place at pressure levels of about 21 to unusually high 50 kg/cm.2 (absolute pressure), and preferably between 24 and 42 kg/cm.2 absolute pressure, for a conversion rate of about 50 to unusually low 85%, preferably 60 to 75 It has also been found that the method of converting low according to the invention is not advantageous over the entire possible range conversions, but only in a range of process conditions which will be specified in more detail subsequently. The example below illustrates further the improved method of the invention and the preferred conditions of implementing it. The effluent leaving the regenerator R L is cooled in the boiler B 2 up to 370 °c about, and then directed toward the converter transient human c-L where most of the carbon monoxide is converted to carbon dioxide, with complementary formation of hydrogen. The water that evaporates in the boiler B 2 may come from any suitable source, and it is particularly advantageous, in this case, use the contaminated condensate obtained after the conversion phase transient, and to recycle the contaminated steam into the furnace regenerator R-L, as well as recited hereinafter in more detail. Numbers are drawn, during the implementation of the improved process according to the invention, several different modes of applying the conversion phase transient, e.g. by using two or more different catalysts to different thermal levels. An additional quantity of heat is recovered in the vapor exiting the converter c-L, as indicated opposite the boiler B 3 and of the heat exchanger W L, after which the process steam enters the hot side of the recuperator thermochemical B 4 or the surplus steam, in condensing, provides power to regenerate according to the known solutions purification Vicieae, such as monoethanolamine and potassium carbonate aqueous, used to extract carbon dioxide content in the hydrogen. The hot condensate to separate at about 127 °c in the separator S-L and the process steam is cooled in the exchanger e 2 to approximately room temperature, substantially all of the vapor is condensed. After taking the cold condensate contained by the separator s 2, the crude hydrogen is subjected to the step of extracting the c02 . The hydrocarbon content of hydrogen after the extraction of the c02 is particularly high, approximately To remove hydrocarbons inert, the partially purified gas is sent to a phase cryoablation where hydrogen and hydrocarbon are separated according to the mode known to about - 168 - 178 to■°g. The cryogenic separation requires the use of external energy, indicated on the schema into a refrigerant compressed and expanded. Industrial hydrogen gas from the cryogenic separation to about - 173 °c contains about 98.5% hydrogen and is now capable of use in a hydrogenation process. The hydrocarbon separated from hydrogen is removed from the cryogenic apparatus under relatively low pressure. A further advantage of the method according to the invention lies in the fact that the cryogenic apparatus is capable of separating carbon monoxide and so as to reduce in the hydrogen product to the value of 100 parts per million, or less, thereby eliminating the need for a phase methanation in treatments hydrogenation using a catalyst responsive to carbon monoxide. Another advantage of the inventive method is that it is very suitable for simultaneous treatment of foreign currents of hydrogen at low purity, or the refocusing of purge gas or recycle from the hydrogenation apparatus. The attached drawing shows these gas entering the apparatus for extracting the c02 for purification, it is say to remove acidic components, such as c02 or H2 O, but if they are sufficiently pure gas may be introduced straight into the cryoablation. From the calculations performed in the context of the present invention, it has been found that the method which in fact the object, when implemented within application conditions indicated above, saves cost advantageous compared with the conventional equipment operating regeneration under a pressure in the range of 8.5 - 9 kg/cm.2 (relative pressure). In a plant to produce 340,000 M.3 industrial hydrogen per day, the usage of the cryogenic purification phase requires a complementary power of about 500 resume when compressing refrigerant, plus a capital investment of the order of 5 million franc 1964 as equipment for cryogenic treatment. However, the method of the present invention markedly reduced needs for compressing the hydrogen and enables the production of a sufficient amount of residual steam in the regeneration boiler waste heat in order to drive all compressors of the installation. For example, in a plant to produce 340,000 M.3 daily hydrogen, adopting this method and a regeneration pressure of the order of 35 kg/cm.2 (relative pressure) decreases the energy required to compress hydrogen of about 1,200 basing relative to the energy required to operate the regeneration under a pressure of 8.5 - 9 kg/cm.2 . This represents a net gain of 700 horses, after deduction of 500 resume necessary to perform the purification by cryoablation. Further, in such a facility, the application of the inventive method and the adoption of a relative pressure of 35 kg/cm in regeneration2 allows the production of a sufficient amount of residual steam, from the boiler primary regeneration waste-heat, to drive all compressors of the installation, even if hydrogen is for end use for hydrogenation under a pressure equal to or greater than 210 kg/cm.2 in relative pressure. In a plant of the same size, when regeneration is carried out according to the conventional method at a relative pressure of 8.5 - 9 kg/cm.2 and with a high level of conversion, there is a clear deficiency in the supply of steam, and all of the power required for compression purposes should come from an external source. Further, the method according to the invention has the following advantages compared to the conventional process: a it requires about 50 c.. It will work reconcentration of the hydrogen from the purge gas and using To make maximum use of the method according to the invention, there is a need to meet running conditions hereinafter: 1° maintain the conversion rate of hydrocarbons into hydrogen and carbon monoxide, during the regeneration phase, between about 50 2° maintain pressure, during the regeneration phase, between 21 and 50 kg/cm.2 (absolute pressure), <PICT:1025104/C1/1> In the production of hydrogen from hydrocarbons by the steps of reforming with steam and shift conversion, an improvement is effected by maintaining a steam-to-carbon ratio of 3 to 7 and a pressure of 300 to 700 p.s.i.a. in the reformer, converting 50 to 85% of the hydrocarbons to hydrogen in the reforming step, removing carbon oxides and steam from the process stream and cryogenically separating unconverted hydrocarbons from hydrogen to give 96% to 99.5% pure hydrogen. Contaminated process condensate (principally dissolved CO2, H2 and hydrocarbons), obtained after shift conversion, may be vaporized and recycled to the reformer. Low-purity hydrogen from an extraneous source may be purified by addition to the process stream prior to cryogenic separation. As shown, hydrocarbon and steam are preheated, e.g. to 750 DEG F., and fed to reformer R-1, inlet pressure being e.g. 500 p.s.i.g. and outlet temperature being e.g. 1480 DEG F. R-1 exit gases are cooled to e.g. 700 DEG F. in B-2 before entry to shift converter C-1. Contaminated process condensate may be evaporated in boilers B-2 and B-3. Two or more catalysts may be used at different temperatures in the shift conversion stage. C-1 exit gases pass through boiler B-3, heat exchanger E-1, and boiler B-4, in which spent solutions from the CO2 removal stage are regenerated by heat exchange. Condensate is collected in separator S-1 at e.g. 260 DEG F. from the process stream, which is further cooled to ambient temperature in heat exchanger E-2, more condensate being removed in separator S-2. Carbon dioxide is removed from the process stream before unconverted hydrocarbons are separated in the cryogenic unit at e.g. -270 DEG F. to -290 DEG F. and 250 to 650 p.s.i.a. If the hydrogen is required for high pressure hydrogenation, compression to e.g. 650 to 1500 p.s.i.a. may be effected prior to the cryogenic step. Carbon monoxide may be separated in the cryogenic unit to give hydrogen containing not more than 100 p.p.m. carbon monoxide. Purge gas or recycle gas from a hydrogenation unit may be added to the process stream either before or after the CO2 removal stage. 1° in the process of producing hydrogen from hydrocarbons, comprising the steps of operating the regenerative catalytic hydrocarbon with steam and to effect the conversion of transient product of said catalyst regeneration, to cool the product of said conversion transient in order to condense the vapor it contains and the separating hydrogen, and effecting separation of carbon dioxide from hydrogen, the improvement comprises 50% to 85% of converting hydrocarbons to hydrogen and carbon oxides in said catalytic regeneration phase, and finally the cryogenic separation of most hydrocarbons with hydrogen of untransformed ponr provide hydrogen of high purity. The improvement in 2° 1 degrees, the purity of the hydrogen product is between 96% and 99.5 The improvement in 3° 1 degrees, there is maintained in said catalytic regeneration phase steam/carbon ratio of 3.0 to 7.0 and a pressure of 21 kg/cm.2 50 kg/cm. to about2 about. The improvement in 4° 1 degrees, the conversion of the hydrocarbons into hydrogen and carbon oxides in said catalytic regeneration phase is in the range of between 60 The improvement in 5° 3 degrees, the ratio of steam/carbon in said catalytic regeneration phase is 4.0, the pressure is 35 kg/cm.2 and the conversion of the hydrocarbons into hydrogen and carbon oxides rises to 65%. The improvement in 6° 1 degrees, the degree of purity of the hydrogen product is 98.5%. The improvement in 7° 2 degrees, there is also a phase which comprises adding hydrogen, before proceeding to the cryogenic separation, hydrogen complementary low purity for purifying the hydrogen complementary to a degree of about 96% to about 99.5 In the method according to 1 8° degrees, there is a complementary phase which vaporizes the condensate which contains contaminants and recycle it in the catalyst regeneration zone. The improvement in 9° 8 degrees, is effected vaporization of at least a portion of said condensate by means of heat exchange with the product of the catalytic regeneration phase. The improvement in 10° 8 degrees, is effected vaporization of at least a portion of said condensate by means of heat exchange with the product of the conversion phase transient. The improvement in 11° 8 degrees, there is maintained in said catalytic regeneration phase steam/carbon ratio of 3.0 to 7.0 and a pressure of 21 kg/cm.2 50 kg/cm. to about2 about. The improvement in 12° 8 degrees, there is maintained in said catalytic regeneration phase steam/carbon ratio of 3.5 to 6.0 and pressure of 42 kg/cm from 24 to2 , vaporizing substantially all of the condensate that contains contaminants, and recycled product in the catalyst regeneration zone. Franchise Harper for MARSHALL'S Dy Proxy: Dr. RobertPucheuMethod for producing hydrogen.
