Product gas manifold system for a steam reformer

A product gas manifold system for a steam reformer, wherein the steam reformer includes a plurality of reformer tubes within a reformer furnace, and wherein the product gas manifold system comprises:

• (a) a product gas manifold for a synthesis gas produced by steam reforming, arranged outside the reformer furnace and exposed to ambient environment, comprising an outer jacket tube and a gas-conveying inner tube extending concentrically and coaxially over its entire length, the space between the inner tube and the jacket tube being at least partially filled with a first layer of a first insulating material
• (b) a plurality of nozzle tubes arranged along a length of the product gas manifold, each for connecting a reformer tube to the product gas manifold in such a manner that a fluid connection exists between the gas-conveying inner tube and the reformer tube connected thereto,
• (c) a second layer of a second insulating material disposed around the jacket tube over at least a portion of a circumference and over at least a portion of a length,
• (d) a curved outer surface outwardly limiting the second layer of the second insulating material, wherein
• (e) the curved outer surface has a circular arc-shaped or U-shaped profile in the radial direction, open in the direction of the reformer furnace, and following the shape of the jacket tube in the axial direction,
• wherein fiber mats or self-supporting insulating moldings made of a mineral fiber composite material are used as the second insulating material, the curved outer surface being the outer surface of the fiber mats or insulating moldings, or wherein an air layer is used as a second insulating material, the curved outer surface being formed by a curved metal sheet, whereby the air layer is formed as an air gap between the outer side of the jacket tube and the inner side of the metal sheet.