CA1098887A - Nickel-mischmetal-calcium alloys for hydrogen storage - Google Patents
Nickel-mischmetal-calcium alloys for hydrogen storageInfo
- Publication number
- CA1098887A CA1098887A CA288,733A CA288733A CA1098887A CA 1098887 A CA1098887 A CA 1098887A CA 288733 A CA288733 A CA 288733A CA 1098887 A CA1098887 A CA 1098887A
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- Canada
- Prior art keywords
- hydrogen
- mischmetal
- hydrogen storage
- nickel
- calcium
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/30—Hydrogen technology
- Y02E60/32—Hydrogen storage
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- Hydrogen, Water And Hydrids (AREA)
- Filling Or Discharging Of Gas Storage Vessels (AREA)
Abstract
Abstract of the Disclosure A nickel-mischmetal-calcium compound is used to store gaseous hydrogen at pressures up to about 15 atmo-spheres at ambient temperatures. The Ni5Ml-yCay compounds have values of y ranging from about 0.2 to about 0.9.
Alloys conforming to this formula contain from about 4%
to about 27% mischmetal, from about 2% to about 11%
calcium, up to about 15% copper, and the balance essentially nickel.
Alloys conforming to this formula contain from about 4%
to about 27% mischmetal, from about 2% to about 11%
calcium, up to about 15% copper, and the balance essentially nickel.
Description
~C-2889/CAN
The present invention is direc-ted to a method for storing hydrogen by absorption in nickel~mischmetal-calcium alloys.
The use of hydrogen gas as a fuel has received considerable attention during recent years because hydrogen can be generated by a variety of methods that do not rely on fossil fuels, te.g., solar energy, nuclear energy, and water power). One of the principal problems confronting wide acceptance of ~ydrogen as a fuel is related to storage.
At present, hydrogen is commonly stored under relatively high pressure, e.g.~ 136 atmospheres, in steel storage cylinders. This type of storage is adequate for many applications; however, due to weight and bulk requirements, such high-pressure cylinders cannot be readily adapted to the requirements of operational units such as ~ehicles.
Furthermore, in many instances, the required high pressures are considered unsafe.
In order to circumvent the problems attending conventionally used storage methods, considerable attention has been directed recently to the storage of hydrogen as a hydride. Compounds of the type AB5 and commonly referred to as a CaCu5 type of structure have received considerable attention. The compounds have a hexagonal crystal structure and are capable of absorbing hydrogen to a volume density of almost twice that found in liquid hydrogen, roughly 6X1022 atoms/cm3.
In my co-pending Canadian application No.
288,556 filed October 12, 1977, it is shown that CaNi5 offers the capability for storiny hydrogPn at sub-atmospheric pressures. This discovery is in direct contrast ,,~
to the publication by H.H. Van Mal, K.H.J. Buschow, and A.R. Miedema reported in the Journal of the Less-Common Metals, Vol. 35, (1974), which showed an adsorption/
desorption plateau of about 15 atmospheres ~or CaNi5.
It is known from U.S. Patent No. 3,825,418 that Ni5M compounds (where M represents mischmetal) are useful for hydrogen storage. However, the minimum hydrogen pres-sure required for sorption is reported therein to be about 41 atmospheres (600 psi) at 25C.
The preparation of a nickel-rare earth (lanthanum)-calcium compound is shown in U.S. Patent No. 3,883,346.
EIowever, this patent shows that the residual quantity of calcium is undesirable, limiting this element to 0.4 weight percent.
The aforedescribed publication and patents are concerned with compounds or alloys that require relatively high pressures for absorption and storage of hydrogen.
As a consequence, the requirement remains for relatively heavy-walled, low-alloy steel containers, albeit not quite as strong as conventional hydrogen storage cylinders.
It has now been discovered that hydrogen can be advantageously stored in a nickel-mischmetal-calcium compound at pressures between about l atmosphere and 15 atmospheres.
Generally speaking, the present invention is directed to a method for storing hydrogen at pressures ranging from about l atmosphere to about 15 atmospheres comprising contacting a hydrogen containing gas with a granulated Ni5Ml yCay compound, where M represents mischmetal and y is from about 0.2 to about 0.9.
~ s~
Compounds ranging from Ni5Mo 8CaO 2 to Ni5Mo lCaO 9 provide variable hydrogen gas storage at 25C at pressures from about 15 atmospheres to about 1 atmosphere respectively and dependent upon the particular composition of the com-pound as defined by the equation P=28.5 exp.(-2.9y) at a H/M ratio of 0.5 (atomic ratio of the number of hydrogen atoms to the number of metal atoms), at 25C, with P being the desorption pressure in atmospheres. The ratio of nickel to mischmetal plus calcium on an atomic basis should be from about 4.5 to about 5.5 and preferably from about 4.8 to about 5.2.
The foregoing shows that more favorable hydrogen storage conditions, from the standpoint of high pressure safety, can be provided than available through the use of a NisM compound which is relatively unstable and for which a hydrogen dissociation pressure at 25C of about 29 atmospheres was determined experimentally. Conversely, low pressure storage is available in compounds such as Ni5Mo lCaO g of the same magnitude as available in a known Ni5La compound, i.e., about 1.7 atmosphere; however, the cost per gram of hydrogen stored is significantly lower in the nickel-mischmetal-calcium compound. To illu~trate, on the basis of raw material cost alone, a Ni5La compound costs, at current prices, about $1.49 per gram of hydrogen stored, whereas a Ni5Mo lCaO g compound costs $0.44 per gram of hydrogen stored.
Although the compounds of the present invention are significantly lower in cost than Ni5La compounds, they are priced substantially higher than iron-titanium compounds which cost, on a raw materials basis, about $0.20 per gram of hydrogen stored. However, the eompounds of the present invention are substantially insuscep-tible to poisoning by gases such as 2~ CO, CO2, CH4, etc. Contamination by sueh gases restricts the capaeity of iron-titanium eom-pounds for hydrogen storage and limits their use to gas streams eontaining high purity hydrogen.
The eompounds of this invention are generally prepared on a weight basis since the individual ingredlents are eombined by melting; and hence, it is convenient to deseribe the compound in the terminology eommonly used for alloy preparation.
The compounds or alloys of this invention eon-tain, in weight percent, from about 4% to about 27% miseh-metal, from about 2% to about 11~ ealcium, with the balance essentially nickel. In order to minimi~e the eost of the raw materials used in the preparation of the alloy, it has been found expedient to substitute some eopper in place of the niekel. Up to about 17.3 weight pereent eopper ean be 5ubsti-tuted for niekel for this purpose. However, substitution of eopper substantially lowers the hydrogen storage eapaeity o the alloy so that on the basis of material eost per gram of hydrogen stored, this substitution is considered to be more expensive than the nickel~mischmetal-caleium alloys as will be shown hereinafter. E~owever, the substitution of copper in part for nickel can serve to improve the resistance of the alloy to contamination by gases such as CO, CO2, N2, etc.
Preferred alloys contain, in weight pereent, from about 6% to about 15% mischmetal, from about 6% to about 10% calcium, and the balance essentially nickel. A most preferred alloy contains about 12% mischmetal, about 8%
calcium, and the balance essentially nickel. Such a preferred alloy offers the lowest raw material cost per gram of hydrogen storage and a favorable dissociation pressure ranging from about 6 atmospheres down to about 1.3 atmospheres absolute.
As will be understood by those skilled in the art, the use of the expression 7'balance es.sentially" does not exclude the presence of other elements commonly present as incidental elements, e.g., the deoxidizing and cleansing aid elements, and impurities normally associated therewith in small amounts which do not adversely affect the novel characteristics of the alloys.
The compounds or alloys can be prepared by air melting or by vacuum melting and casting into ingot molds as hereinafter described.
Following cooling to room temperature, the ingots are removed from the molds and crushed to granular form.
A U.S. Standard Mesh Size of about -4 has been found appropriate for hydriding applications.
The crushed and sieved alloy is introduced to a suitable, valved pressure vessel for hydriding. Initial hydriding or activation can be accomplished by evacuating the vessel and then introducing gaseous hydrogen at ambient temperatures and pressures above about 5 atmospheres, twith the minimum pressure dependent on composition). The alloy begins to absorb hydrogen almost immediately and is gener-ally fully hydrided within about one hour. Once the nickel-calcium-mischmetal alloy is charged with hydrogen, the vessel is valved oEf and ready for use as a source of hydrogen. Subsequent recharging with hydrogen is accom-plished in time periods significantly less than one hour, e.g., lQ minutes.
The aforedescribed vessels can be used for any number of applications, including the provision of a hydrogen atmosphere to ~ furnace, as a fuel source for an internal combustion engine, etc.
For the purpose of giving those skilled in the ; art a better understanding of the invention, the following examples are given:
EXAMPLES
Eight kilogram heats having the compositions shown in Table I were prepared by induction melting. The alloys identified as 1 and 2 were melted under vacuum in an alumina crucible. The alloys identified as 3 through 6 and the alloys outside of the invention identified as A and B were all prepared by air melting in a clay-graphite crucible, (e.g., a number 30 crucible sold under the Trademark DIXAGRAF and available from Joseph Dixon Crucible Company).
In the air-induction melting practic~, nickel is melted, mischmetal added, and the calcium plunged below the surface of the melt. The melt is induction stirred to ~8~
provide thorough mixing of the ingredients and poured into ingot molds.
A vacuum melting practice consists of melting nickel under a vacuum of about 10 2 Torr, adding mischmetal, backfilling the vacuum chamber with argon to a pressure of about 380 Torr, adding calcium, inductively stirring for about one minute, and pouring into ingot molds. The melt temperature should be maintained below about 1500C to sub-stanitally avoid reduction of the alumina crucible.
Mischmetal is a mixture of rare-earth elements in metallic form; the rare-earth elements have atomic numbers between 57 and 71. The commercially produced mischmetal used to prepare the alloys of this invention was obtained from the Molybdenum Corporation of America and contained about 48 to 50% cerium, 32 to 34~ lanthanum, 13 to 14 neodymium, 4 to 5% praseodymium, and about 1.5% other rare-earth metals. As those skilled in the art will understand other commercially available grades of mischmetal can be substituted for preparation of the alloys of ~his invention, (e.g., a cer~um-free mischmetal).
Eight grams of -10 mesh, +14 mesh granules of the nickel-mischmetal-calcium alloys were placed in a 15mm diameter by 35mm high reactor vessel. A vacuum pump was used to remove air from this chamber to achieve a vacuum of about 10 2 Torr. The vacuum source was valved off and ultra high purity hydrogen introduced to the apparatus. For experimental purposes, a hydrogen pressure of 68 atmospheres was used to pressurize the apparatus. It was observed that the specimens began to activate immediately and absorb lar~e quantities of hydrogen. The specimens ~ere essen-tially saturated with hydrogen within a time period of generally about one hour.
Hydrogen desorption pressures were measured at 25C as a function of H/M ratio (atomic ratio of the number r of hydro~en atoms to the number of metal atoms). E'or each alloy, a slopin~ dissociation pressure plateau was found to exist for H/M ratios from about 0.2 to about 0.7.
10Table II shows the results of the dissociation pressure tests for the alloys identified as 1 through 6, ~ and B.
The dissociation plateau for Alloy A, a nickel-mischmetal alloy, ranged from 26.0 to 31.5 atmospheres as compared to dissociation pressures of 13.0 to 15.4 for the nlckel mischmetal alloy, No. 1, containing about 2 weight percent calcium. At the other end of the spectrum, Alloy B, a Ni5Ca compound, had a sub-atmospheric dissociation pressure of 0.41-0.56 atmospheres, whereas the dissociation pressure of a nickel-calcium alloy containing about 5%, by weight, mischmetal was 0.8-1.8 atmosphere. Thus, Alloys 1 through 5 show that levels of dissociation pressure intermediate to that available in either the excessively high values available in nickel-mischmetal or the excessively low values available in nickel-calcium.
Also shown in Table II is an alloy, identified as No. 6, containing one part of copper substituted for one of the normal 5 parts of nic~el. Although copper lowers the dissociation pressure somewhat, it decreases the hydrogen TABLE I
IDENTIFICATION AND COMPOSITION
OF HYDRIDABLE COMPOVNDS
Analysis in weigh-t percent, balance Ni Approxima-te Actual Rare Alloy Value of y Formula of Earth Identity ~ Cay Compound Ni Metals Ca O N C Al 0.2 5 0.80 0.19 1.8 0.0011 0.0050 (2) 0.032
The present invention is direc-ted to a method for storing hydrogen by absorption in nickel~mischmetal-calcium alloys.
The use of hydrogen gas as a fuel has received considerable attention during recent years because hydrogen can be generated by a variety of methods that do not rely on fossil fuels, te.g., solar energy, nuclear energy, and water power). One of the principal problems confronting wide acceptance of ~ydrogen as a fuel is related to storage.
At present, hydrogen is commonly stored under relatively high pressure, e.g.~ 136 atmospheres, in steel storage cylinders. This type of storage is adequate for many applications; however, due to weight and bulk requirements, such high-pressure cylinders cannot be readily adapted to the requirements of operational units such as ~ehicles.
Furthermore, in many instances, the required high pressures are considered unsafe.
In order to circumvent the problems attending conventionally used storage methods, considerable attention has been directed recently to the storage of hydrogen as a hydride. Compounds of the type AB5 and commonly referred to as a CaCu5 type of structure have received considerable attention. The compounds have a hexagonal crystal structure and are capable of absorbing hydrogen to a volume density of almost twice that found in liquid hydrogen, roughly 6X1022 atoms/cm3.
In my co-pending Canadian application No.
288,556 filed October 12, 1977, it is shown that CaNi5 offers the capability for storiny hydrogPn at sub-atmospheric pressures. This discovery is in direct contrast ,,~
to the publication by H.H. Van Mal, K.H.J. Buschow, and A.R. Miedema reported in the Journal of the Less-Common Metals, Vol. 35, (1974), which showed an adsorption/
desorption plateau of about 15 atmospheres ~or CaNi5.
It is known from U.S. Patent No. 3,825,418 that Ni5M compounds (where M represents mischmetal) are useful for hydrogen storage. However, the minimum hydrogen pres-sure required for sorption is reported therein to be about 41 atmospheres (600 psi) at 25C.
The preparation of a nickel-rare earth (lanthanum)-calcium compound is shown in U.S. Patent No. 3,883,346.
EIowever, this patent shows that the residual quantity of calcium is undesirable, limiting this element to 0.4 weight percent.
The aforedescribed publication and patents are concerned with compounds or alloys that require relatively high pressures for absorption and storage of hydrogen.
As a consequence, the requirement remains for relatively heavy-walled, low-alloy steel containers, albeit not quite as strong as conventional hydrogen storage cylinders.
It has now been discovered that hydrogen can be advantageously stored in a nickel-mischmetal-calcium compound at pressures between about l atmosphere and 15 atmospheres.
Generally speaking, the present invention is directed to a method for storing hydrogen at pressures ranging from about l atmosphere to about 15 atmospheres comprising contacting a hydrogen containing gas with a granulated Ni5Ml yCay compound, where M represents mischmetal and y is from about 0.2 to about 0.9.
~ s~
Compounds ranging from Ni5Mo 8CaO 2 to Ni5Mo lCaO 9 provide variable hydrogen gas storage at 25C at pressures from about 15 atmospheres to about 1 atmosphere respectively and dependent upon the particular composition of the com-pound as defined by the equation P=28.5 exp.(-2.9y) at a H/M ratio of 0.5 (atomic ratio of the number of hydrogen atoms to the number of metal atoms), at 25C, with P being the desorption pressure in atmospheres. The ratio of nickel to mischmetal plus calcium on an atomic basis should be from about 4.5 to about 5.5 and preferably from about 4.8 to about 5.2.
The foregoing shows that more favorable hydrogen storage conditions, from the standpoint of high pressure safety, can be provided than available through the use of a NisM compound which is relatively unstable and for which a hydrogen dissociation pressure at 25C of about 29 atmospheres was determined experimentally. Conversely, low pressure storage is available in compounds such as Ni5Mo lCaO g of the same magnitude as available in a known Ni5La compound, i.e., about 1.7 atmosphere; however, the cost per gram of hydrogen stored is significantly lower in the nickel-mischmetal-calcium compound. To illu~trate, on the basis of raw material cost alone, a Ni5La compound costs, at current prices, about $1.49 per gram of hydrogen stored, whereas a Ni5Mo lCaO g compound costs $0.44 per gram of hydrogen stored.
Although the compounds of the present invention are significantly lower in cost than Ni5La compounds, they are priced substantially higher than iron-titanium compounds which cost, on a raw materials basis, about $0.20 per gram of hydrogen stored. However, the eompounds of the present invention are substantially insuscep-tible to poisoning by gases such as 2~ CO, CO2, CH4, etc. Contamination by sueh gases restricts the capaeity of iron-titanium eom-pounds for hydrogen storage and limits their use to gas streams eontaining high purity hydrogen.
The eompounds of this invention are generally prepared on a weight basis since the individual ingredlents are eombined by melting; and hence, it is convenient to deseribe the compound in the terminology eommonly used for alloy preparation.
The compounds or alloys of this invention eon-tain, in weight percent, from about 4% to about 27% miseh-metal, from about 2% to about 11~ ealcium, with the balance essentially nickel. In order to minimi~e the eost of the raw materials used in the preparation of the alloy, it has been found expedient to substitute some eopper in place of the niekel. Up to about 17.3 weight pereent eopper ean be 5ubsti-tuted for niekel for this purpose. However, substitution of eopper substantially lowers the hydrogen storage eapaeity o the alloy so that on the basis of material eost per gram of hydrogen stored, this substitution is considered to be more expensive than the nickel~mischmetal-caleium alloys as will be shown hereinafter. E~owever, the substitution of copper in part for nickel can serve to improve the resistance of the alloy to contamination by gases such as CO, CO2, N2, etc.
Preferred alloys contain, in weight pereent, from about 6% to about 15% mischmetal, from about 6% to about 10% calcium, and the balance essentially nickel. A most preferred alloy contains about 12% mischmetal, about 8%
calcium, and the balance essentially nickel. Such a preferred alloy offers the lowest raw material cost per gram of hydrogen storage and a favorable dissociation pressure ranging from about 6 atmospheres down to about 1.3 atmospheres absolute.
As will be understood by those skilled in the art, the use of the expression 7'balance es.sentially" does not exclude the presence of other elements commonly present as incidental elements, e.g., the deoxidizing and cleansing aid elements, and impurities normally associated therewith in small amounts which do not adversely affect the novel characteristics of the alloys.
The compounds or alloys can be prepared by air melting or by vacuum melting and casting into ingot molds as hereinafter described.
Following cooling to room temperature, the ingots are removed from the molds and crushed to granular form.
A U.S. Standard Mesh Size of about -4 has been found appropriate for hydriding applications.
The crushed and sieved alloy is introduced to a suitable, valved pressure vessel for hydriding. Initial hydriding or activation can be accomplished by evacuating the vessel and then introducing gaseous hydrogen at ambient temperatures and pressures above about 5 atmospheres, twith the minimum pressure dependent on composition). The alloy begins to absorb hydrogen almost immediately and is gener-ally fully hydrided within about one hour. Once the nickel-calcium-mischmetal alloy is charged with hydrogen, the vessel is valved oEf and ready for use as a source of hydrogen. Subsequent recharging with hydrogen is accom-plished in time periods significantly less than one hour, e.g., lQ minutes.
The aforedescribed vessels can be used for any number of applications, including the provision of a hydrogen atmosphere to ~ furnace, as a fuel source for an internal combustion engine, etc.
For the purpose of giving those skilled in the ; art a better understanding of the invention, the following examples are given:
EXAMPLES
Eight kilogram heats having the compositions shown in Table I were prepared by induction melting. The alloys identified as 1 and 2 were melted under vacuum in an alumina crucible. The alloys identified as 3 through 6 and the alloys outside of the invention identified as A and B were all prepared by air melting in a clay-graphite crucible, (e.g., a number 30 crucible sold under the Trademark DIXAGRAF and available from Joseph Dixon Crucible Company).
In the air-induction melting practic~, nickel is melted, mischmetal added, and the calcium plunged below the surface of the melt. The melt is induction stirred to ~8~
provide thorough mixing of the ingredients and poured into ingot molds.
A vacuum melting practice consists of melting nickel under a vacuum of about 10 2 Torr, adding mischmetal, backfilling the vacuum chamber with argon to a pressure of about 380 Torr, adding calcium, inductively stirring for about one minute, and pouring into ingot molds. The melt temperature should be maintained below about 1500C to sub-stanitally avoid reduction of the alumina crucible.
Mischmetal is a mixture of rare-earth elements in metallic form; the rare-earth elements have atomic numbers between 57 and 71. The commercially produced mischmetal used to prepare the alloys of this invention was obtained from the Molybdenum Corporation of America and contained about 48 to 50% cerium, 32 to 34~ lanthanum, 13 to 14 neodymium, 4 to 5% praseodymium, and about 1.5% other rare-earth metals. As those skilled in the art will understand other commercially available grades of mischmetal can be substituted for preparation of the alloys of ~his invention, (e.g., a cer~um-free mischmetal).
Eight grams of -10 mesh, +14 mesh granules of the nickel-mischmetal-calcium alloys were placed in a 15mm diameter by 35mm high reactor vessel. A vacuum pump was used to remove air from this chamber to achieve a vacuum of about 10 2 Torr. The vacuum source was valved off and ultra high purity hydrogen introduced to the apparatus. For experimental purposes, a hydrogen pressure of 68 atmospheres was used to pressurize the apparatus. It was observed that the specimens began to activate immediately and absorb lar~e quantities of hydrogen. The specimens ~ere essen-tially saturated with hydrogen within a time period of generally about one hour.
Hydrogen desorption pressures were measured at 25C as a function of H/M ratio (atomic ratio of the number r of hydro~en atoms to the number of metal atoms). E'or each alloy, a slopin~ dissociation pressure plateau was found to exist for H/M ratios from about 0.2 to about 0.7.
10Table II shows the results of the dissociation pressure tests for the alloys identified as 1 through 6, ~ and B.
The dissociation plateau for Alloy A, a nickel-mischmetal alloy, ranged from 26.0 to 31.5 atmospheres as compared to dissociation pressures of 13.0 to 15.4 for the nlckel mischmetal alloy, No. 1, containing about 2 weight percent calcium. At the other end of the spectrum, Alloy B, a Ni5Ca compound, had a sub-atmospheric dissociation pressure of 0.41-0.56 atmospheres, whereas the dissociation pressure of a nickel-calcium alloy containing about 5%, by weight, mischmetal was 0.8-1.8 atmosphere. Thus, Alloys 1 through 5 show that levels of dissociation pressure intermediate to that available in either the excessively high values available in nickel-mischmetal or the excessively low values available in nickel-calcium.
Also shown in Table II is an alloy, identified as No. 6, containing one part of copper substituted for one of the normal 5 parts of nic~el. Although copper lowers the dissociation pressure somewhat, it decreases the hydrogen TABLE I
IDENTIFICATION AND COMPOSITION
OF HYDRIDABLE COMPOVNDS
Analysis in weigh-t percent, balance Ni Approxima-te Actual Rare Alloy Value of y Formula of Earth Identity ~ Cay Compound Ni Metals Ca O N C Al 0.2 5 0.80 0.19 1.8 0.0011 0.0050 (2) 0.032
2 0 5 5 0.49 0-45 4.85 0.0005 0.0075 (2) 0.064
3 0.7 Ni5Mo 29Ca0 68 81-3 11-4 7.53 0.030 0.069 0.023
4 0.8 Ni5Mo 20CaO 78 83.2 7.86 8.86 0.059 0.055 0.022 (2) 0.9 Ni5Mo 10Ca0 89 85-5 4.29 10.4 0.12 0.074 0.024 (2) 6 0.7 4 1 0.30 0.67 ()7.36 0.047 0.056 0.017 (2) A 0 Ni5M1 0068.0 32.3(2) 0.010 0.006 (2) 0.029 B 1 Ni5CaO 9888.5 (2)11.8 0.038 0.085 0.018 (2) , ~
(1) Also contains 17.3% Cu.
(2) not analyzed.
8~ ,,~
TABLE II
Dissociation pressures for H/M rations from 0.2 to 0.7 for alloys based on Ni5 Ml_y Cay where y ranges from 0.2 to 0.9 Alloy Value of y in Dissociation pressure, Identity Ni5Ml yCay _atmospheres 1 0.2 13.0 - 15.4 2 0.5 3.5 - 12.3 3 0.7 1.4 - 6.2 4 0.8 1.5 - 4.7 0.9 0.8 - 1.8 6 0.7 1.0 - 15.5 A 0 26.0 - 31.5 : B 1 0.41 - 0.56 TABLE III
Raw Material Cost per Gram of Hydrogen Stored Alloy Approximate Formula Dollars/Gram Identity of Comvound of Hydro~en 1 N i sM o. a C aO- 2 ~ 37 : 2 Ni5MO.5CaO.~ 0.38 3 Ni5MO.3CaO-7 0~35 4 Ni5M 0.2Ca 0-8 - 35 S Ni5MO.1CaO.g 0.44 6 Ni~Cu1MO.3CaO.67 0.48 A Ni5M 0.43 C Ni5La 1.49 storage capacity. Thus, on the basis of raw material cost per gram of hydrogen stored, the copper-containing alloy is somewhat more expensive than copper-free alloys as shown in Table III.
~ lthough it is realized that the cost of preparing any one of the alloys of the present invention is dependent on other factors such as meltinq cost, crushing cost, activation cost, and resistance to gas impurities, Table III
shows that the nickel-mischmetal-calcium alloys are price competitive with nickel-mischmetal, and particularly nickel-lanthanum. Consequently, i~ addition to the advantages of hydrogen absorption at lower pressures, substantially improved insusceptibility to contamination and ease of preparation, the alloys of this invention appear -to offer a cost advantage over presently existing nickel alloys useful for hydrogen storage.
Hydrogen can be absorbed and desorbed from the nickeI-mischmetal-calcium alloy at ambient temperatures of from about -30C to about 100C, preferably from about 0C to about 80~C. The dissociation pressures referred to in Table II were measured at 25C.
Although the present invention has been described ; in con~unction with preferred embodiments, it is to be understood that modifications and variations may be resorted to without departing from the spirit and scope of the invention, as those skilled in the art will readily under-stand. Such modifications and variations are considered to be within the purview and scope o~ the invention and appended claims.
(1) Also contains 17.3% Cu.
(2) not analyzed.
8~ ,,~
TABLE II
Dissociation pressures for H/M rations from 0.2 to 0.7 for alloys based on Ni5 Ml_y Cay where y ranges from 0.2 to 0.9 Alloy Value of y in Dissociation pressure, Identity Ni5Ml yCay _atmospheres 1 0.2 13.0 - 15.4 2 0.5 3.5 - 12.3 3 0.7 1.4 - 6.2 4 0.8 1.5 - 4.7 0.9 0.8 - 1.8 6 0.7 1.0 - 15.5 A 0 26.0 - 31.5 : B 1 0.41 - 0.56 TABLE III
Raw Material Cost per Gram of Hydrogen Stored Alloy Approximate Formula Dollars/Gram Identity of Comvound of Hydro~en 1 N i sM o. a C aO- 2 ~ 37 : 2 Ni5MO.5CaO.~ 0.38 3 Ni5MO.3CaO-7 0~35 4 Ni5M 0.2Ca 0-8 - 35 S Ni5MO.1CaO.g 0.44 6 Ni~Cu1MO.3CaO.67 0.48 A Ni5M 0.43 C Ni5La 1.49 storage capacity. Thus, on the basis of raw material cost per gram of hydrogen stored, the copper-containing alloy is somewhat more expensive than copper-free alloys as shown in Table III.
~ lthough it is realized that the cost of preparing any one of the alloys of the present invention is dependent on other factors such as meltinq cost, crushing cost, activation cost, and resistance to gas impurities, Table III
shows that the nickel-mischmetal-calcium alloys are price competitive with nickel-mischmetal, and particularly nickel-lanthanum. Consequently, i~ addition to the advantages of hydrogen absorption at lower pressures, substantially improved insusceptibility to contamination and ease of preparation, the alloys of this invention appear -to offer a cost advantage over presently existing nickel alloys useful for hydrogen storage.
Hydrogen can be absorbed and desorbed from the nickeI-mischmetal-calcium alloy at ambient temperatures of from about -30C to about 100C, preferably from about 0C to about 80~C. The dissociation pressures referred to in Table II were measured at 25C.
Although the present invention has been described ; in con~unction with preferred embodiments, it is to be understood that modifications and variations may be resorted to without departing from the spirit and scope of the invention, as those skilled in the art will readily under-stand. Such modifications and variations are considered to be within the purview and scope o~ the invention and appended claims.
Claims (12)
1. A method for storing hydrogen at pressures ranging from about 1 atmosphere to about 15 atmospheres comprising, contacting a hydrogen containing gas with a granulated Ni5Ml-yCay compound, where M represents mischmetal and y is from about 0.2 to about 0.9.
2. A method for storing hydrogen as defined in claim 1 wherein a hydrogen desorption pressure (P) is a function of said compound formula according to a relationship P = 28.5 exp.(-2.9y).
3. An alloy for hydrogen storage consisting essentially of, in weight percent, from about 4% to about 27% mischmetal, from about 2% to about 11% calcium, up to about 17.3% copper, and the balance essentially nickel.
4. An alloy for hydrogen storage as defined in claim 3 containing from about 6% to about 15% mischmetal, from about 6% to about 10% calcium, and the balance essentially nickel.
5. An alloy for hydrogen storage as defined in claim 4 containing about 12% mischmetal, about 8% calcium, and the balance essentially nickel.
6. A composition for hydrogen storage having the formula Ni5Ml-yCay, where M represents mischmetal and y is from 0.2 to about 0.9.
7. A composition for hydrogen storage as defined in claim 6 wherein y = 0.2.
8. A composition for hydrogen storage as defined in claim 6 wherein y = 0.5.
9. A composition for hydrogen storage as defined in claim 6 wherein y = 0.7.
10. A composition for hydrogen storage as defined in claim 6 wherein y = 0.8.
11. A composition for hydrogen storage as defined in claim 6 wherein y = 0.9.
12. A composition for hydrogen storage as defined in claim 6 wherein nickel is partly substituted for by copper in the atomic ratio of Ni:Cu - 4:1 and y = 0.7.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US739,483 | 1976-11-08 | ||
| US05/739,483 US4096639A (en) | 1976-11-08 | 1976-11-08 | Nickel-mischmetal-calcium alloys for hydrogen storage |
| US83727877A | 1977-09-30 | 1977-09-30 | |
| US837,278 | 1977-09-30 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1098887A true CA1098887A (en) | 1981-04-07 |
Family
ID=27113543
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA288,733A Expired CA1098887A (en) | 1976-11-08 | 1977-10-14 | Nickel-mischmetal-calcium alloys for hydrogen storage |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPS5392325A (en) |
| CA (1) | CA1098887A (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6070154A (en) * | 1983-09-27 | 1985-04-20 | Japan Metals & Chem Co Ltd | Hydrogen storing material |
| JPS59145752A (en) * | 1983-02-09 | 1984-08-21 | Japan Metals & Chem Co Ltd | Hydrogen occluding material |
| JPS59125582U (en) * | 1983-02-15 | 1984-08-23 | 松下電工株式会社 | Structure of the water tank of a simple flush toilet |
| JPS6085711U (en) * | 1983-11-18 | 1985-06-13 | 三洋電機株式会社 | Composite magnetic head |
-
1977
- 1977-10-14 CA CA288,733A patent/CA1098887A/en not_active Expired
- 1977-11-07 JP JP13337377A patent/JPS5392325A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5392325A (en) | 1978-08-14 |
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