RU2124928C1 - Device for hydrogen generation - Google Patents

Abstract

FIELD: devices for conversion of hydrocarbon raw materials, applicable in reconstruction of acting installations for production of industrial hydrogen with arrangement of part of production equipment in rooms classified as explosion-hazardous. SUBSTANCE: the device has a hydrocarbon raw material and hydrogen feed line, heat exchange, desulfurization apparatus, saturator, heat exchanger for heating of steam- gas mixture, methane converter, heat exchangers for cooling the converted gas, carbon oxide converter, heat exchanger and compressor, adsorber for gas cleaning of carbon dioxide, and an adsorption cleaning unit for emission of pure hydrogen, the unit has two parallel lines, each including three series-connected adsorbers located in a common housing intended for depressurization of one or several adsorbers or line of adsorbers, in each adsorber the height-to-diameter ratio is more than 8. EFFECT: enhanced degree of output of final product. 2 cl, 1 dwg

Description

 The invention relates to installations for the conversion of hydrocarbons and can be used in the chemical, metallurgical and other industries for the production of process gases, including hydrogen, as well as in the reconstruction of existing plants for the production of technical hydrogen with the placement of part of the technological equipment in rooms categorized as explosive.

 A known method for producing high-purity hydrogen, including the production of a mixture of synthesis gas of carbon monoxide and hydrogen, the conversion of synthesis gas to carbon monoxide and hydrogen and purification of the obtained hydrogen by adsorption. (Patent US N 5152976, MKI-6, C 01 B 3/26, 10/06/92). The method is carried out in an installation corresponding to the steps of the process for producing hydrogen and providing a degree of hydrogen purification of 99.75%. However, this method and installation do not provide a high yield of the target hydrogen product and the release of carbon dioxide as one of the products during the purification of industrial hydrogen.

 There is also a method of producing hydrogen from hydrocarbon feedstock (gas) by conducting steam conversion of hydrocarbons, conversion of carbon monoxide, purification of the converted gas from carbon oxides and methane by short-cycle adsorption (CCA) with hydrogen evolution and subsequent regeneration of the adsorbent by purging with a part of hydrogen to produce regeneration gases and returning them after heating and compression to the methane conversion stage. (Nitrogen, 1980, N 122, v. 98, p. 38).

 An installation providing the implementation of this method includes a hydrocarbon (natural gas) conversion reactor, a carbon monoxide converter, a heat exchanger, a unit for adsorption purification of hydrogen from carbon oxides, short-cycle adsorption methane (CCA), an adsorbent regeneration unit, and a compressor.

 The disadvantages of this method and installation is the low degree of methane conversion and low yield of the target product - hydrogen, increased steam consumption and increased energy consumption for conversion, heating of regeneration gases and their compression to the pressure of the vapor-gas mixture. In addition, this installation cannot ensure the production of converted gas at a pressure of about 0.07 MPa.

 The closest in technical essence and the achieved result is a method for producing hydrogen from hydrocarbon feedstocks and an installation (circuit) in which this method is carried out as described in RF patent N 2088518, MKI-6, C 01 B 3/32, 08/27/97.

The known method includes steam conversion of hydrocarbon feedstock (gas) to produce a gas containing hydrogen and carbon monoxide, supplying the obtained gas to the conversion of carbon monoxide, cooling the converted gas to separate carbon dioxide from it, and purifying the resulting gas from carbon oxides and methane using the short-cycle method adsorption at elevated pressure to obtain the target product - hydrogen and subsequent regeneration of the adsorbent by purging part of the hydrogen produced, and short-cycle adsorption in they go under pressure of 15-30 kgf / cm ² , and the regeneration gases are sent to the stage of carbon monoxide conversion.

The installation for carrying out the method includes lines for supplying hydrocarbon feedstocks — natural gas and hydrogen, a heat exchanger, a desulfurization apparatus connected in series with it, a saturator for saturating water vapor with the addition of a certain amount of superheated steam, a heat exchanger for heating the gas mixture to 540 ^o C, methane converter, heat exchanger for cooling the converted gas, carbon monoxide converter, compressor for compressing up to 18 atm of cooled converted gas containing a mixture of H ₂ , CO, CH ₄ and N ₂ , block short cyclic adsorption (CCA) for the release of pure hydrogen, free from impurities, as well as a purge for directing desorption gases into the apparatus for the conversion of carbon monoxide.

 The disadvantages of this method and installation for its implementation should include a low yield of the target product is hydrogen when cleaning the converted gas by the method of short-cycle adsorption.

 Due to the presence of nitrogen in the original process gas, which accumulates in the hydrogen-containing gas to be cleaned, an increase in blow-off is required, while the quality of the extracted hydrogen decreases.

 The objective of the invention is to increase the efficiency of the process for producing hydrogen by creating an installation with such an arrangement of technological equipment (nodes, lines) that would allow the use of premises and sites with a categorization of explosion hazard.

The problem is solved in the proposed installation for the production of technical hydrogen from hydrocarbon feedstock, including the supply line of hydrocarbon feedstock and hydrogen, a heat exchanger and a desulfurization apparatus connected in series with it, a saturator to saturate the gas mixture with water vapor, a heat exchanger for heating the gas mixture to 520-540 ^o C, methane converter, heat exchangers for cooling the converted gas, carbon monoxide converters, heat exchanger and compressor for compressing the cooled converted gas, adsorber for Cleaning the gas from carbon dioxide, as well as adsorption purification unit for separation of pure hydrogen, which consists of two parallel lines each of which includes three series-connected adsorbers arranged in a single casing, wherein in each adsorber height ratio to the diameter of the adsorber is more than 8.

 In addition, the housing in which the adsorbers are located is designed for depressurization of one or more adsorbers or a line of adsorbers.

 A diagram of the proposed installation is shown in FIG. 1 and includes lines for supplying natural gas (1) and hydrogen (2) to a heat exchanger (3) connected in series with a desulfurization apparatus (4), a saturator (5), a heat exchanger (6), a methane converter (7), and a heat exchanger (8 ) The apparatus with medium temperature conversion of carbon monoxide (9) is connected in series with the apparatus for low temperature conversion of carbon monoxide (10). After the scrubber-cooler (11), the installation contains a compressor for compressing the synthesis gas to 2.4-2.6 MPa (12) and an adsorber for water purification of the converted gas from carbon dioxide (13). The final part of the installation is a system of activated carbon adsorbers (14), consisting of two parallel lines, each of which consists of three series-connected adsorbers placed in a single housing (15).

 Obtaining technical hydrogen in such an installation is as follows.

Natural gas (1) from the factory collector is mixed with hydrogen (2) under a pressure of 0.35 MPa to hydrogenate sulfur compounds and, after heating to 380 ^° C, in a convective heater (3) of the tube furnace, it is fed to the desulfurization stage in the apparatus (4), where it is cleaned gas from sulfur compounds to its residual content in the purified gas is less than 0.5 mg / m ³ . The purified natural gas is saturated with water vapor in a ratio of 3: 1 in the saturator (5) and after overheating in the preheater-heat exchanger (6) installed in the duct after the radiation chamber (7) of the tube furnace, up to 520-540 ^o C are fed to the bottom of the reaction pipes installed in the radiation chamber of the converter (7) with panel burners and burners for flat burning of the waste fraction of hydrogen purification. The reaction mixture, rising from bottom to top along the nickel catalyst layer, absorbs heat from the combustion of fuel gas, due to which the conversion process occurs with the decomposition of hydrocarbons into CO, CO ₂ and H ₂ , while the temperature of the converted gas rises to 820 - 860 ^o C, and the residual methane content in the converted gas is reduced to 0.9 - 0.6%.

The reacted converted gas through an internal gas exhaust pipe, giving off the heat of the reacting vapor-gas mixture, is cooled to 540 - 560 ^o C and with this temperature is removed from the reaction pipes. After cooling in a heat exchanger (8) to a temperature of 360 ^° C, gas is supplied to a medium temperature carbon monoxide converter (9), and then after additional cooling to 200 - 210 ^° C, to a low temperature carbon monoxide conversion converter (10). The carbon monoxide content in dry gas after low-temperature conversion does not exceed 0.6%. After cooling due to circulating water in a scrubber-cooler (11), the converted gas is mixed with desorption gases, compressed in a compressor (12) to a pressure of 2.4 - 2.6 MPa and fed to an aqueous purifier (13) to remove carbon dioxide. The converted gas purified from CO _{2 is} fed to the final purification stage - to the activated carbon adsorbers block system (14, 15), in which the adsorption process is carried out with a long cycle, i.e., impurities are adsorbed from the technical hydrogen to produce pure hydrogen for technical purposes. Hydrogen purification is carried out on two lines, each of which consists of three adsorbers connected in series with a ratio of height to diameter of the adsorber casing of more than 8, and placed in a single casing (15), the design pressure of which exceeds the design pressure of the discharge compressors.

 Such an arrangement of the nodes of the adsorption process will allow for the reconstruction of existing hydrogen production facilities to place equipment in rooms with an explosion hazard category, because In each adsorption purification apparatus, separate stages of absorption of impurities, depressurization with inert blowing, and the stage of thin blowing of the sorption surface with pure hydrogen occur.

 Impurity blow-off gas and fine-pressure hydrogen under atmospheric pressure are removed from the adsorbers and sent for burning in the burners of the flat flame, placed in the arch of the tube furnace with panel burners.

 Carbon dioxide when depressurized is desorbed from water and sent to the consumer.

Claims (2)

1. Installation for production of technical hydrogen, including lines for supplying hydrocarbon feedstocks and hydrogen, a heat exchanger and a desulfurization apparatus connected in series with it, a saturator for saturating the gas mixture with water vapor, a heat exchanger for heating the gas mixture to 520 - 540 ^o C, methane converter, heat exchangers for converting gas cooling, carbon monoxide converter, heat exchanger and compressor for compressing cooled converted gas, an adsorber for purifying carbon dioxide from gas, as well as an adsorption unit ki for the isolation of pure hydrogen, characterized in that the adsorption purification unit consists of two parallel lines each of which includes three series-connected adsorbers arranged in a single casing, wherein in each adsorber height to diameter ratio of the adsorber is more than 8.  2. Installation according to claim 1, characterized in that the housing in which the adsorbers are placed is designed for depressurization of one or more adsorbers or a line of adsorbers.