US1781935A - Production of hydrogen - Google Patents

Description

Nov. 1 1930. F. T. SNYDER 3 PRODUCTION OF-HYDROGEN Filed Dec.- 16, 1925 fi'e/en'ck Snyder Patented Nov. 3, 19st PATENT OFFICE FREDERICK T. SN YDER, OF NEW CAN-LAN, CONNECTICUT ahzonucrron or HYDROGEN Application fled December 16, 1925, Serial- No. 75,795,-and in Canada March 12, 1925.- v

This invention relates broadly to the art of hydrogenating hydrocarbons and carbo-. hydrates, and more particularly to a method or process of producing, at low cost and in 5 large. quantities, hydrogen or gas mixtures containing a large amount of free hydrogen and suitable forhydrogenation processes.

Generally s'peaking,;the inventionresidesin cracking natural gas 'or'gas distilled-from ing the same in contact with hot refractory material in closed chambers with exclusion of air, and burning with air in the chambers the carbon de osited from the cracking operation, to relieat' the refractory material. These [operations are-performed alternately. It is, of course,'well known that methane, thev chief constituent of natural gas, can be dissociated into hydrogen and carbon by heating the gas to a sufiiciently high temperature with exclusion of air. Other gases or hydrocarbon vapors with high hydrogen content ma be cracked in the same way,

according to the nature of the original gas or vapor. The carbon deposited when natural as is cracked is suflicient in amount, 1 when urned with air, to furnish more heat than necess'ar to eflectthe cracking. The excess heat 0 sets-loss by radiation and may be used to heat'the produced highhydrogen to generate steam, or for other purposes. ii; the economic accomplishment of these results, it is essential that the gas should pass through the cracking chamber tions the incoming cold gas and. cold air operate to sweep the heat toward the centre centre. Preferably v the interior of the cracking chamber is a brickwork checker.

To facilitate comprehension of the invention,"one manner ofputting the same into practice will be described, reference being made'to the accompanying diagrammatic drawing illustrating one suitable form of ap tus.

Earring more particularly to the drawwhich diagrammatically represents a .verticalsectional view of suitable apparatus,

coal, oil or other suitable material, by pass? yielding hy rogen, carbon and residual gases" and air.

the chamber and produce a hot zone at the through a pipe 16 controlled by a valve 17.

The air for the burning of the deposited carbon enters through a pipe 18 having a valve 19, and th'e.,products of the combustion of the carbon leaves through the pipe 20 in which is a valve 21. The air is'supplied by a blower 18.

Carbon having been deposited on the refractories in the centre zone of the checkerwork 13, thehot and cold gas valves 15 and '17 are closed and the air valve 19 and the stack valve 21 are opened. The passage of the hot .gas on the previous cycle having heated the checkerwork at the--lower end 22, the incoming air is heated and at the same time this end of the checkerwork is cooled.

The heated air burns the deposited .carbon causing a high temperature .in the centre 7 zone... This heat is absorbed by the checkerwork and part of it is carriedout ofthe centre zone by the productsof the combustion which have also risen to a high temperature from the combustion. The upper end 23 of the 'checkerworkis cool as the result of the. incoming cold gas sweeping over'it in the preceding cycle. The hot products of the combustion leaving the centre zone give up most of their heat to this cooled buckin opposite directions. Under these condigas valves 15 and 17 are opened. The incomcold gas is heated gradually by the heat 7 e in the upper zone 23 of thecheckerwork: by the on oingflproducts of the combustion. When this eat temperature so high' that all of the-h drocar bon compounds, such as methane an ethane, are decomposed. This decomposition is sub- 9 gas reaches the centrezone of the checkerwork 13, the gas is carried toa' 90 e air and stack pipes are closed and the stantially complete at 1500 F., but inpractice the checkerwork in the centre zone is heated to 1800 F. to shorten the time of the decomposition. As the cracking is largely brought about by the contact of the gas with the hot checkerwork, the carbon freed as the result ofthe cracking isin contact with the checkerwork and adheres to it as a solid deposit. This adherence is facilitated by the fact that the carbon, if the temperature is not too high, contains some hydrogen, so that the deposit is in the form of a sticky but hard tar. The gas leaves the centre cracking zone ata high temperature, which is lowered by the absorption of some of itsheat by the brickwork in the lower part 22 of the checkerwork, which had been cooled by the incoming cold air in the-previous combustion 0 dc. The partially cooled gas leaves the c eckerwork through the pipe 16.

These cycles are then alternately repeated. To secure a continuous supply of hot cracked gas, two checkerworks can be used, each delivering cracked gas while the carbon is being burned out of the other one, or the cracked gas can be stored in a gase holder from which gas can be supplied through a pipe 26 during the interval when the carbon is being burned out of the checkerwork. The gas holder may be of any suitable form such as the inverted bell 24 water sealed in a tank 25.

' With some natural gases, the amount of carbon deposited is so large that, more .heat would be developed than can be absorbed if all this carbon were burned to carbon-dioxide. Under these conditions, the supply of air can be limited and part of the carbon burned to carbon monoxide with the production of less heat, yet with the complete removal of the carbon, due to the high temperature of the combustion and the consequent displacement of the condition of chemical equilibrium toward the production of carbon monoxide.

Gas or vapors produced from coal, oil or other materials may be cracked in the same way. I

This invention can also be used for cracking the vapors or heavy oils into the vapors of hghter oils. All such cracking means the reduction of the percentage of carbon inthe vapor, and in this invention this rejected carbon is deposited on the hot checkerwork and by its combustion furnishes the required heat for the operation. Where such heavy oils. have a temperature of vaporization at normal pressure that is above their decomposition temperature, they may be evaporated at lower pressures into a large volume of gas high in' ydrogenand such suspendedvapor may be cracked irt-aceordance with this invention. 'In. such caset tio of carbon tohydrogen will not'only be" ed the decomposition of a some of the aceo inp "'j'fying carbon but, under th'e unstable condition iii-the oil molecule produced by the hi h temperature, some of the surrounding hy rogen will also be absorbed, further lowering the ratio of carbon to hydrogen in the molecule and correspondingly low I ering the boiling temperature of the original oil vapor. p a

Having thus described my invention, what I claim is 1. A process ofmaking hydrogen by decomposing hydrocarbon gas, which comprises passing t e gas in} contact with refractory material of increasing temperature with exclusion of air, the maximum temperature of said material being above the decomposing temperature of said gas, and then of decreasing temperature, the decomposition being accompanied by deposition of carbon near the material of maximum temperature, subsequently burning said deposited carbon with heated air to re-heat said material, and absorbing art of the heat of the products of said com ustion in the part of said material with which said gas initially came in contact.

2. A process of making hydrogen by decomposing hydrocarbon vapors which com prises passing the vapors in contact with refractory material of gradually increasing temperature until the temperature of said material is above the decomposition temperature of said vapor with exclusion of air a with deposition'upon said material of maximum temperature of the carbon resulting from the decomposition of said vapor, and then bringing the gaseous products of said decomposition in contactwith said material of gradually decreasing temperature subsequently re-heating said material'at the point of maximum temperature by burning said deposited carbon with a current of air, passing through saidmaterial-in a-direction contrary to the direction of passage of said vapor.

3. A process of making products of high hydrogen percentage content from hydrocarbon gas or vapour having hydrogen percentage content lower than that of the desired products, which comprises passing the same through a refractory c eckerwork highly heated in its intermediate port'on and 'cooler toward-the ends with heating of the gas in the first ortion of the chec erwork encountered by t e gas or vapour, cracking of the gas or vapour in said intermediate hot "portion of the checkerwork and deposit of carbon therein, and heating of the last portion of the checkerwork encountered by the hot cracked gas, and when the temperature of the intermediate portion of the checkerwork drops below an efiicient gas or vapour cracking temperatureistoppin the gas flow and passing air through the c eckerwork in the opposite direction to the gas or vapour with heating of the air in the first part of the checkerwork encountered by the air, combustion of the deposited carbon in the interof products of combustion in the ortion of the checkerwork first encountered y the gas or vapour, cracking the gas or'v'apour in an intermediate portion of the checkerwork by heat remaining in said portion from burning carbon deposited by a previous cracking operation, heating the portion of the checkerwork last encountered by the cracked gas with heat carried by the gas out of the cracking zone,

heating air with the heat left in the checkerwork first encountered by the air from emerging cracked gas, burning carbon deposited in an intermediate portion of thecheckerwork by the previous cracking operi i the maximum temperature of the refractory hand.

ation with said heated air thereby reheating the checkerwork to cracking temperature, and reheating the portion of checkerwork first encountered by the gas or vapour with the heat of the products of carbon combustion.

5. A process of making hydrogen by decomposing hydrocarbon gas, which comprises progressively heating the gas to a temperature above its decomposition temperature and then progressively cooling the gas, the heating and cooling being effected by passing-the gas in contact with a mass of refractory ma-. terial heated to temperatures progressively higher and then progressively lower along the path of the gas.

6. A process according to claim 5, in which the maximum temperature of the gas is approximately 1500 F.

7. A process according to claim 5, in which material is approximately 1 800 F.

In witness whereof, I have hereunto set my FREDERICK T. SNYDER.

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