Process for producing pure hydrogen with low steam export
AssigneeL'Air Liquide, Societe Anonyme pour l'Etude et l'Exploitation des Procedes Georges Claude
InventorsSwatantra Kumar SHRIVASTAVA, Dieter ULBER, Mirko HUEBEL
Life of this patent
Estimating the term…
Abstract
A process is proposed for producing pure hydrogen by steam reforming of a feed gas comprising hydrocarbons, preferably natural gas or naphtha, with a simultaneously low and preferably adjustable export steam flow rate. The process includes the steam reforming of the feed gas, for which the heat of reaction required is provided by combustion of one or more fuel gases with combustion air in a multitude of burners arranged within the reformer furnace. According to the invention, the combustion air, before being introduced into the burners, is heated by means of at least one heat exchanger in indirect heat exchange with the hot flue gas to temperatures of at least 530° C.
Claims17
A process for producing a pure hydrogen product gas by steam reforming of a feed gas containing hydrocarbons, comprising:
- (a) providing the feed gas comprising hydrocarbons,
- (b) providing a hydrogen production plant comprising
- (b1) a prereformer,
- (b2) a steam reforming plant with a reformer furnace, comprising
- (b21) a multitude of reformer tubes filled with steam reforming catalyst, wherein the reformer tubes have a feed gas inlet for a feed gas mixture on a first side of the reformer furnace and a product gas outlet for a crude synthesis gas on a second side of the reformer furnace, wherein the second side is opposite the first side, and further comprising
- (b22) a multitude of burners,
- (b3) a CO conversion plant,
- (b4) a hydrogen purification plant,
- (c) adding steam to the feed gas to obtain a steam-feed gas mixture having an overall SIC ratio,
- (d) introducing the steam-feed gas mixture into the prereformer, prereforming the steam-feed gas mixture under prereforming conditions to give a prereformed feed gas comprising hydrogen, carbon oxides, methane and higher hydrocarbons, discharging the prereformed feed gas,
- (e) introducing the prereformed feed gas into the feed gas inlet of the reformer tubes of the steam reforming plant, heating the reformer tubes by means of the burners, wherein the burners are operated with a fuel gas containing a proportion of the feed gas as trim gas and a proportion of a recycled combustible offgas stream, and with combustion air, wherein the operation of the burners produces a hot flue gas,
- (f) steam reforming the prereformed feed gas under steam reforming conditions to give a crude synthesis gas comprising hydrogen, carbon oxides and unconverted hydrocarbons and having a crude gas temperature, discharging the crude synthesis gas from the product gas outlet of the reformer tubes,
- (g) introducing the crude synthesis gas into the CO conversion plant, performing the CO conversion under CO conversion conditions, discharging a converted crude synthesis gas having elevated hydrogen content relative to the crude synthesis gas,
- (h) introducing the converted crude synthesis gas into the hydrogen purification plant, discharging a pure hydrogen product gas and at least one combustible offgas stream, wherein
- (i) the combustion air prior to introduction into the burners is heated up by means of at least one heat exchanger in indirect heat exchange with the hot flue gas to a temperature between 530 and 790° C.
Dependencies are inferred from the claim text.