Hydrogen generating composition, reactor, device and hydrogen production method

Abstract

The present invention discloses a hydrogen generating composition, reactor, device and hydrogen production method. The composition includes sodium borohydride and a filler. The filler is a substance having a chemical stability and a water solubility of less than 10 g per 100 g of water under an alkaline or neutral condition at a temperature of 130 C. to 140 C. The filler has a bulk volume of 0.0216 times the bulk volume of the sodium borohydride. A mass ratio between the filler and the sodium borohydride is less than or equal to 2:1. The filler has a bulk density of less than 16 and has a mean particle size smaller than that of the sodium borohydride. The present invention has a high hydrogen production density, adequate reaction, lower cost and is environmentally friendly, practical and simple to pause and restart.

Claims

1. A sodium borohydride-containing composition for generation of hydrogen, comprising sodium borohydride and a filler, wherein the filler is a substance having a chemical stability and a water solubility of less than 10 g per 100 g of water under an alkaline or neutral condition at a temperature of 130 C. to 140 C., where the chemical stability is an absence of decomposition of the substance and an absence of a chemical reaction with the sodium borohydride or water, and wherein the filler has a bulk volume of 0.02 to 16 times a bulk volume of the sodium borohydride, a mass ratio between the filler and the sodium borohydride being no greater than 2:1, the filler having a bulk density of less than 16 g/cm.sup.3, the filler having a mean particle size smaller than a mean particle size of the sodium borohydride, and wherein the alkaline condition is an alkalinity resulting from moisture-caused hydrolysis of the sodium borohydride or a reaction product NaBO.sub.2 thereof, and wherein the chemical reaction does not include simple hydration and the decomposition does not include simple dehydration.

2. The sodium borohydride-containing composition according to claim 1, wherein the mass ratio of the filler to the sodium borohydride is no greater than 0.5:1.

3. The sodium borohydride-containing composition according to claim 1, wherein the filler is a substance having a bulk density of less than 0.5 g/cm.sup.3.

4. The sodium borohydride-containing composition according to claim 3, wherein the filler is a substance having a bulk density of less than 0.1 or the filler is magnesium hydroxide.

5. The sodium borohydride-containing composition according to claim 3, wherein the filler is a foamed plastic pellet.

6. The sodium borohydride-containing composition according to claim 1, wherein the sodium borohydride has a mean particle size of no less than 0.1 mm and no greater than 2 mm.

7. The sodium borohydride-containing composition according to claim 6, wherein the sodium borohydride has a mean particle size of no less than 0.2 mm and no greater than 1 mm.

8. The sodium borohydride-containing composition according to claim 1, wherein the bulk volume of the filler is 0.2 to 8 times the bulk volume of the sodium borohydride.

9. The sodium borohydride-containing composition according to claim 8, wherein the bulk volume of the filler is 2 to 4 times the bulk volume of the sodium borohydride.

10. A method for generation of hydrogen, comprising the step of subjecting the sodium borohydride-containing composition according to claim 1, to a temperature in a range of 110 to 160 C. and bringing the sodium borohydride-containing composition in contact with water vapor.

11. The method according to claim 10, wherein the temperature is in a range of 120 to 150 C.

12. The method according to claim 10, wherein the temperature is in a range of 110 to 160 C. and gradually declines.

13. A reactor for generation of hydrogen, wherein the reactor is filled with the sodium borohydride-containing composition according to claim 1 and provided with a fluid inlet and a fluid outlet.

14. An apparatus for generation of hydrogen, comprising the reactor according to claim 13, a liquid container and a heater, wherein the liquid container and the reactor are directly or indirectly connected together in a fixed or detachable manner.

15. The apparatus according to claim 14, wherein the liquid container contains water.

16. The sodium borohydride-containing composition according to claim 1, wherein the mean particle size of the filler is smaller than 0.5 times the mean particle size of the sodium borohydride.

17. The apparatus according to claim 14, wherein the liquid container is tubular.

18. The apparatus according to claim 14, wherein the heater is arranged in proximity to the reactor or disposed in the reactor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 illustrates an apparatus for generation of hydrogen according to embodiments of the present invention, where 1 indicates a liquid container, 2 a liquid pump, 3 a reactor, 4 a heater, and 5 a temperature sensor.

DETAILED DESCRIPTION

(2) The invention is explained in greater detail below on the basis of several embodiments and should not be construed as limited thereto. It is intended that any process, which conditions are not specified, involved in the embodiments should be construed as being performed in the same conditions as it is commonly performed, or in the conditions described in descriptive literature of associated products used therein.

(3) Materials mentioned in the present invention are all commercially available:

(4) TABLE-US-00001 Material Specifications Provider NaBH.sub.4 Particle size: 0.2~1.0 mm Available in the market NaBH.sub.4 Particle size: 0.1~0.2 mm Selected from a commercially available product having a broader particle size range, by sieving in a dry envi- ronment NaBH.sub.4 Particle size: 1.0~1.5 mm Selected from a commercially available product having a broader particle size range, by sieving in a dry envi- ronment Mg(OH).sub.2 White light powder, with a Shanghai Tongya particle size of 100~200 chemical Technology mesh and a bulk density of Development Co., Ltd. about 0.4 Foamed Model: H850D; Material of Manufactured by the plastic shells: Acrylonitrile/Meth- Japanese Dainichiseika pellets acrylonitrile/Methylmeth- Color & Chemicals Mfg. acrylate co-polymer; Co., Ltd. and available Encapsulated foaming agent: from Shanghai Jiaowei mixed C.sub.5H.sub.12 and C.sub.8H.sub.18; Chemical Material Co., Minimum foaming temperature: Ltd. about 125 C.; Maximum foaming temperature: about 180 C.; Mean particle size before foaming: about 30 m; Mean particle size after foaming: about 120 m. Embodiments of this invention uses products foamed at 175 C. for 5 minutes with a bulk density of about 0.002. Disposable 10 ml, with a plastic barrel Shengguang Medical medical Instrument Co., Ltd. syringe

(5) The embodiments share the following common features:

(6) The liquid container 1 is implemented as a beaker, which contains water; the liquid pump 2 is implemented as a peristaltic pump; the reactor 3 is implemented as a disposable medical syringe filled with the composition. The reactor 3 is immersed in glycerol contained in a glass cup. A heater 4 is disposed in a lower part of the glass cup and in proximity to the reactor; a temperature sensor 5 is further included, wherein both the heater 4 and the temperature sensor 5 are connected to an external temperature controller and an external power supply. See FIG. 1.

(7) The barrel of the syringe serves as a housing of the reactor 3. The needle of the syringe is discarded and the open end of the barrel where the needle is originally fitted serves as a fluid inlet of the reactor 3. The fluid inlet is connected to an outlet of the peristaltic pump by a silicone hose with an inner diameter of 0.8 mm. The plunger of the syringe is pulled off and the rubber piston is detached from the plunger. The rubber piston is used to seal the other open end of the syringe through which the plunger is originally inserted in the syringe. A small opening is created at the center of the rubber piston as an outlet for hydrogen to exit the barrel. A length of at least 150 mm of the silicone hose is immersed in the glycerol such that water is sufficiently vaporizable before entering the reactor 3. The reactor is oriented vertically with the fluid inlet pointing upward.

(8) The composition (or the NaBH.sub.4 in each of the following Comparative Examples) is filled in the reactor to a position as near as permissible to the fluid inlet, and thereafter another, same rubber piston also bored with a small opening at the center is fitted, together with a piece of ordinary filter paper, into the barrel in an upward direction to prevent the composition (or the NaBH.sub.4) from falling out of the barrel.

(9) The production of hydrogen is estimated from the amount of expelled water.

(10) Since mass transfer occurring on the surface of NaBH.sub.4 particles is the rate-determining step of the reaction, most water vapor introduced in the reactor escapes with the produced hydrogen during the reaction, which causes the non-stoichiometry between a hydrogen production rate and a water flow rate supplied by the peristaltic pump, however, in practical applications, those of ordinary skill in this art can design a means, for example, a heat exchanger, to easily recycle the escaped water vapor as well as the heat loss due thereto for reuse.

(11) Hydrogen generation during the temperature increasing phase is considered to be caused by an insufficiently dry state of the composition.

(12) Unless specified otherwise, the NaBH.sub.4 with a particle size of 0.21.0 mm is used.

Embodiment 1

(13) A composition with a bulk volume of 5.5 cc was prepared by mixing together 1.9 g (about 0.05 Mol) of NaBH.sub.4 with a bulk volume of about 4 cc and 0.95 g of Mg(OH).sub.2 with a bulk volume of about 2.4 cc, and was filled in the reactor and compacted to a volume of 5 cc using the rubber piston.

(14) The temperature of the glycerol was controlled in the range of 1305 C., and the flow rate of the peristaltic pump was set to 0.01 g/min.

(15) In a temperature increasing phase before the peristaltic pump was activated, a volume of 195 cc of hydrogen was generated. After activating the pump, hydrogen was produced at an initial rate of about 350 cc/hour, and the rate started to slowly decrease 5 hours later. After the reaction had run for 7 hours, the pump was shut down for 8 hours, and during this period, 135 cc of hydrogen was further generated. Afterward, the reaction was restarted and further ran for 6 hours so that the reaction lasted for a total duration of 13 hours. The experiment was stopped when the hydrogen production rate dropped to about 150 cc/hour.

(16) The reaction produced a total of 4050 cc of hydrogen at an adequacy of 90.4% relative to a theoretical production of 4480 cc.

(17) The residual product of the reaction had a gross mass of 4.40 g and a net mass of 3.45 g obtained by subtracting the mass of the Mg(OH).sub.2 therefrom.

Embodiment 2

(18) A similar experiment as conducted in Embodiment 1 was conducted except that 1.3 g of Mg(OH).sub.2 with a bulk volume of about 3.2 cc was used and a composition with a bulk volume of 6 cc was prepared, and that the composition was not compacted after it was filled in the reactor.

(19) The reaction produced a total of 4090 cc of hydrogen at an adequacy of 91.3% relative to a theoretical production of 4480 cc.

(20) The residual product of the reaction had a gross mass of 4.55 g and a net mass of 3.25 g obtained by subtracting the mass of the Mg(OH).sub.2 therefrom.

Embodiment 3

(21) A composition with a bulk volume of about 11 cc was prepared by mixing together 1.9 g (about 0.05 Mol) of NaBH.sub.4 with a bulk volume of about 4 cc and foamed plastic pellets with a bulk volume of about 10 cc (the weight of the pellets was too small to be measured), and was filled in the reactor and compacted to a volume of 8 cc using the rubber piston.

(22) The temperature of the glycerol was controlled in the range of 1305 C., and the flow rate of the peristaltic pump was set to 0.03 g/min.

(23) In a temperature increasing phase before the peristaltic pump was activated, a volume of 190 cc of hydrogen was generated. After activating the pump, hydrogen was produced at an initial rate of about 900 cc/hour, and the rate decreased slowly with the proceeding of the reaction. After the reaction had run for 3 hours, the pump was shut down for 8 hours, and during this period, 290 cc of hydrogen was further generated. Afterward, the reaction was restarted and further ran for 3 hours so that the reaction lasted for a total duration of 6 hours. The experiment was stopped when the hydrogen production rate dropped to about 270 cc/hour.

(24) The reaction produced a total of 4270 cc of hydrogen at an adequacy of 95.3% relative to a theoretical production of 4480 cc.

(25) The residual product of the reaction had a gross mass of 3.35 g, which is also its net mass due to the negligible weight of the foamed plastic pellets.

Embodiment 4

(26) A similar experiment as conducted in Embodiment 3 was conducted except that the temperature of the glycerol was controlled in the range of 1405 C.

(27) In a temperature increasing phase before the peristaltic pump was activated, a volume of 190 cc of hydrogen was generated. After activating the pump, hydrogen was produced at an initial rate of about 500 cc/hour, and the rate decreased slowly with the proceeding of the reaction. After the reaction had run for 5 hours, the pump was shut down for 8 hours, and during this period, 20 cc of hydrogen was further generated. Afterward, the reaction was restarted and further ran for 7.5 hours so that the reaction lasted for a total duration of 12.5 hours. The experiment was stopped, when the hydrogen production rate dropped to about 150 cc/hour.

(28) The reaction produced a total of 4240 cc of hydrogen at an adequacy of 94.6% relative to a theoretical production of 4480 cc.

(29) The residual product of the reaction had a gross mass (also its net mass) of 3.3 g.

Embodiment 5

(30) A similar experiment as conducted in Embodiment 3 was conducted except that the temperature of the glycerol was controlled in the range of 1505 C. in initial and medium phases, and 1205 C. in a later phase, of the reaction.

(31) In a temperature increasing phase before the peristaltic pump was activated, a volume of 330 cc of hydrogen was generated.

(32) After the pump was activated, hydrogen was produced at an initial rate of about 200 cc/hour, and the rate decreased slowly with the proceeding of the reaction to 120 cc/hour after 16 hours. The pump was then shut down for 8 hours, during which 10 cc of hydrogen was further generated, and the reaction was thereafter restarted and further ran for 18 hours, after which the hydrogen production rate dropped to 50 cc/hour. This stage of reaction could be called the initial and medium phases.

(33) The temperature of the glycerol was adjusted to 1205 C., at which the reaction further ran for 1 hour to generate 150 cc of hydrogen and the experiment was stopped thereafter. This stage of reaction could be called the later phase.

(34) The reaction produced a total of 4220 cc of hydrogen at an adequacy of 94.2% relative to a theoretical production of 4480 cc.

(35) The residual product of the reaction had a gross mass (also its net mass) of 3.55 g, which was probably caused by a proneness of the product to moisture absorption at a temperature around 120 C.

(36) On basis of this result, a reasonable prediction can be made that a relatively constant hydrogen production rate can be obtained by employing a control system equipped with an adaptive algorithm to gradually reduce the reaction temperature throughout the whole course of the reaction.

Embodiment 6

(37) A similar experiment as conducted in Embodiment 3 was conducted except that the temperature of the glycerol was controlled in the range of 1205 C.

(38) The composition was fluidized and flowed out of the reactor in liquid drops 12 hours after the reaction was started, and the experiment was stopped.

(39) In combination with the result of Embodiment 5, it can be found that a lower temperature is desirable for a later period of the reaction but not for an initial period.

Embodiment 7

(40) A composition with a bulk volume of 4 cc was prepared by mixing together 1.9 g (about 0.05 Mol) of NaBH.sub.4 with a bulk volume of about 4 cc and 0.05 g of Mg(OH).sub.2 with a bulk volume of about 0.125 cc, and was filled in the reactor.

(41) The temperature of the glycerol was controlled in the range of 1305 C., and the flow rate of the peristaltic pump was set to 0.01 g/min.

(42) In a temperature increasing phase before the peristaltic pump was activated, a volume of 160 cc of hydrogen was generated. After activating the pump, the rate of hydrogen production gradually increased to about 400 cc/hour and then slowly decreased. After the reaction had run for 6 hours, the pump was shut down for 8 hours, and during this period, 110 cc of hydrogen was further generated. Afterward, the reaction was restarted and stopped 7 hours later (i.e., the total reaction period was 13 hours), when the hydrogen production rate dropped to about 150 cc/hour.

(43) The reaction produced a total of 3760 cc of hydrogen at an adequacy of 83.9% relative to a theoretical production of 4480 cc.

(44) The residual product of the reaction had a gross mass of 3.05 g and a net mass of 3.0 g obtained by subtracting the mass of the Mg(OH).sub.2 therefrom.

Embodiment 8

(45) A composition with a bulk volume of 4 cc was prepared by mixing together 1.9 g (about 0.05 Mol) of NaBH.sub.4 with a bulk volume of about 4 cc and 0.4 g of Mg(OH).sub.2 with a bulk volume of about 1 cc, and was filled in the reactor.

(46) The temperature of the glycerol was controlled in the range of 1405 C., and the flow rate of the peristaltic pump was set to 0.03 g/min.

(47) In a temperature increasing phase before the peristaltic pump was activated, a volume of 160 cc of hydrogen was generated. After activating the pump, hydrogen was produced at an initial rate of about 400 cc/hour, and the rate decreased slowly with the proceeding of the reaction. After the reaction had run for 4 hours, the pump was shut down for 8 hours, and during this period, 20 cc of hydrogen was further generated. Afterward, the reaction was restarted and stopped 8 hours later (i.e., the total reaction period was 12 hours), when the hydrogen production rate dropped to about 150 cc/hour.

(48) The reaction produced a total of 3910 cc of hydrogen at an adequacy of 87.3% relative to a theoretical production of 4480 cc.

(49) The residual product of the reaction had a gross mass of 3.6 g and a net mass of 3.2 g obtained by subtracting the mass of the Mg(OH).sub.2 therefrom.

Embodiment 9

(50) A similar experiment as conducted in Embodiment 4 was conducted except that the NaBH.sub.4 with a particle size of 0.10.2 mm was used.

(51) In a temperature increasing phase before the peristaltic pump was activated, a volume of 220 cc of hydrogen was generated. After activating the pump, hydrogen was produced at an initial rate of about 500 cc/hour, and the rate decreased slowly with the proceeding of the reaction. After the reaction had run for 5 hours, the pump was shut down for 8 hours, and during this period, 20 cc of hydrogen was further generated. Afterward, the reaction was restarted and stopped 6.5 hours later (i.e., the total reaction period was 11.5 hours), when the hydrogen production rate dropped to about 150 cc/hour.

(52) The reaction produced a total of 4040 cc of hydrogen at an adequacy of 90.2% relative to a theoretical production of 4480 cc.

(53) The residual product of the reaction had a gross mass (also its net mass) of 3.2 g.

Embodiment 10

(54) A similar experiment as conducted in Embodiment 4 was conducted except that the NaBH.sub.4 with a particle size of 1.01.5 mm was used.

(55) In a temperature increasing phase before the peristaltic pump was activated, a volume of 120 cc of hydrogen was generated. After activating the pump, hydrogen was produced at an initial rate of about 400 cc/hour, and the rate decreased slowly with the proceeding of the reaction. After the reaction had run for 5 hours, the pump was shut down for 8 hours, and during this period, 20 cc of hydrogen was further generated. Afterward, the reaction was restarted and stopped 7.5 hours later (i.e., the total reaction period was 12.5 hours), when the hydrogen production rate dropped to about 150 cc/hour.

(56) The reaction produced a total of 3700 cc of hydrogen at an adequacy of 82.6% relative to a theoretical production of 4480 cc.

(57) The residual product of the reaction had a gross mass (also its net mass) of 3.1 g.

Comparative Example 1

(58) 1.9 G (about 0.05 Mol) of NaBH.sub.4 with a bulk volume of about 4 cc was filled in the reactor.

(59) The temperature of the glycerol was controlled in the range of 1305 C., and the flow rate of the peristaltic pump was set to 0.01 g/min.

(60) In a temperature increasing phase before the peristaltic pump was activated, a volume of 40 cc of hydrogen was generated. After activating the pump, hydrogen was produced at an initial rate of about 200 cc/hour, and the rate slowly increased to about 400 cc/hour thereafter. However, the NaBH.sub.4 was fluidized and flowed out of the reactor in liquid drops 7 hours later, and the experiment was stopped.

(61) A comparison to those Embodiments described above in which the temperature was controlled to 1305 C. demonstrated that if the composition of the present invention was not used, the reaction would possibly stop halfway even when it was carried out in the same conditions.

Comparative Example 2

(62) A composition with a bulk volume of 4 cc was prepared by mixing together 1.9 g (about 0.05 Mol) of NaBH.sub.4 with a bulk volume of about 4 cc and 0.02 g of Mg(OH).sub.2 with a bulk volume of about 0.05 cc, and was filled in the reactor.

(63) The temperature of the glycerol was controlled in the range of 1305 C., and the flow rate of the peristaltic pump was set to 0.01 g/min.

(64) In a temperature increasing phase before the peristaltic pump was activated, a volume of 130 cc of hydrogen was generated. After activating the pump, the rate of hydrogen production gradually increased to about 400 cc/hour and then slowly decreased. After the reaction had run for 5 hours, the pump was shut down for 8 hours, and during this period, 80 cc of hydrogen was further generated. Afterward, the reaction was restarted and stopped 7 hours later (i.e., the total reaction period was 12 hours), when the hydrogen production rate dropped to about 150 cc/hour.

(65) The reaction produced a total of 3260 cc of hydrogen at an adequacy of 72.8% relative to a theoretical production of 4480 cc.

(66) After the reaction, significant distortion and shrinkage, as well as slight drooling and dropping, were observable in the solid stuff in the reactor.

(67) A comparison to those Embodiments described above in which the temperature was controlled to 1305 C. demonstrated that even when the reaction was carried out in the same conditions, an inappropriately low content of the filler in the composition of the invention would lead to an undesirable adequacy of the reaction and drooling and dropping of the solid stuff, which might cause clogging in fluid passage in the apparatus.

Comparative Example 3

(68) 1.9 G (about 0.05 Mol) of NaBH.sub.4 with a bulk volume of about 4 cc was filled in the reactor.

(69) The temperature of the glycerol was controlled in the range of 1405 C., and the flow rate of the peristaltic pump was set to 0.03 g/min.

(70) In a temperature increasing phase before the peristaltic pump was activated, a volume of 120 cc of hydrogen was generated. After activating the pump, hydrogen was produced at an initial rate of about 400 cc/hour, and the rate started to slowly decreased 4 hours later. After the reaction had run for 5 hours, the pump was shut down for 8 hours, and during this period, 10 cc of hydrogen was further generated. Afterward, the reaction was restarted and stopped 6 hours later (i.e., the total reaction period was 11 hours), when the hydrogen production rate dropped to about 150 cc/hour.

(71) The reaction produced a total of 3300 cc of hydrogen at an adequacy of 73.7% relative to a theoretical production of 4480 cc.

(72) The residual product of the reaction had a net mass of 2.95 g.

(73) A comparison to those Embodiments described above in which the temperature was controlled to 1405 C. demonstrated that if the composition of the present invention was not used, an undesirable low adequacy would be resulted even when the reaction was carried out in the same conditions.

(74) It is intended to include all simple modifications known to those skilled in the art in the scope of the invention.