System for hydrogen generation through steam reforming of hydrocarbons and intergrated chemical reactor for hydrogen production from hydrocarbons

Abstract

The present invention provides a reactor, which includes: a unitary shell assembly having an inlet and an outlet; a flow path extending within the shell assembly from the inlet to the outlet, the flow path having a steam reformer section with a first catalyst and a water gas shift reactor section with a second catalyst, the steam reformer section being located upstream of the water gas shift reactor section; a heating section within the shell assembly and configured to heat the steam reformer section; and a cooling section within the shell assembly and configured to cool the water gas shift reactor section. The present invention also provides a simplified hydrogen production system, which includes the catalytic steam reforming and subsequent high temperature water gas shift of low-sulfur (<100 ppm by mass) hydrocarbon fuels followed by hydrogen purification through the pressure swing adsorption (PSA). The integrated reactor offers significant advantages such as lower heat loss, lower parts count, lower thermal mass, and greater safety than the many separate components employed in conventional and is especially well-suited to applications where less than 15,000 standard cubic feet per hour of hydrogen are required. The improved system also may be started, operated and shut down more simply and quickly than what is currently possible in conventional systems. The improved system preferably employs active temperature control for added safety of operation. The hydrogen product is of high purity, and the system may be optionally operated with a feedback control loop for added purity.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to an integrated chemical reactor for the production of hydrogen from hydrocarbon fuels such as natural gas, propane, liquefied petroleum gas, alcohols, naphtha and other hydrocarbon fuels and having a unique unitized, multifunctional structure. The integrated reactor offers significant advantages such as lower heat loss, lower parts count, lower thermal mass, and greater safety than the many separate components employed in conventional systems to achieve the same end. The integrated reactor is especially well-suited to applications where less than 15,000 standard cubic feet per hour of hydrogen are required. [0003] The present invention also relates to the generation of hydrogen for use in industrial applications, as a chemical feedstock, or as a fuel for stationary or mobile power plants. [0004] 2. Discussion of the Background [0005] Hydrogen production from natural gas, propane, liqu...

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Benefits of technology

[0029] Accordingly, one object of the present invention is to provide a reactor ...

Problems solved by technology

For several reasons, it is difficult to adapt these large-scale technologies to economically produce hydrogen at small scales.

Further, the extent of the reaction is low at low temperatures, such that greatly elevated temperatures, often as high as 800° C., are required by conventional systems to convert an acceptable amount of hydrocarbon to hydrogen and carbon monoxide.

The radiantly-fired furnaces employed in large-scale industrial reactors have many disadvantages that make them unsuitable for small-scale systems.

The most important disadvantage is the very high temperature of the radiant burners and the gas contacting the reactor surfaces, which are usually tubular in form.

If, however, the catalyst fails due to carbon formation, sulfur poisoning or other causes, then the tubes form what is referred to in the literature as a “hot spot,” which greatly accelerates the failure of the reactor tube in question.

For systems producing below 1 ton per day, however, the complexity and cost of such safety measures can become prohibitive.

In all cases, the low temperature shift converter is quite large because of the poor catalyst activity at low temperatures.

For systems producing less than 1 ton per day, however, the unit process approach has many disadvantages.

The first disadvantage is the high proportion of the total system mass dedicated to the hardware and plumbing of the separate components.

This high mass increases startup time, material cost, and system total mass, which is undesirable for mobile applications such as powerplants for vehicles.

Another disadvantage of the unit process approach in small systems is the complexity of the plumbing system to connect the components.

The complexity increases the likelihood of leaks in the final system, which presents a safety hazard, and also significantly increases the cost of the assembly process itself.

Moreover, the requirement that each component have its own inlet and outlet provisions also adds considerable manufacturing cost to the components themselves.

A third disadvantage is the high surface area of the plumbing relative to the unit process hardware itself, which means that a disproportionately large amount of heat is lost through the connecting plumbing in small scale systems.

This can drastically reduce the thermal efficiency of the system and adds cost and complexity associated with adequately insulating the plumbing system.

A fourth disadvantage to the unit process approach in small-scale systems is that this approach requires a large volume to package, as each component and its associated plumbing must be accessible for assembly and maintenance purposes.

This is particularly disadvantageous in space-sensitive applications such as building fuel cell power stations, fuel cell vehicle refueling stations, and fuel cell mobile powerplant hydrogen generation.

These catalysts, typically based on nickel metal in the former and copper in the latter case, are extremely sensitive to poisoning and deactivation by sulfur or molecular oxygen.

Especially ...

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