Post-combustion lance including an internal support assembly

A post-combustion lance for directing a gas at least partially therethrough, the post-combustion lance comprising:

• a body at least partially defined by an axis thereof and extending between an upstream end and a downstream end of the lance, the upstream end being adapted to receive the gas, and the downstream end comprising a primary tip through which a first part of the gas exits the lance;
• the body comprising:
• upper and lower portions;
• a post-combustion distributor mounted between the upper and lower portions at a predetermined distance from the primary tip, the distributor comprising a plurality of ports through which a second part of the gas exits the lance, the upper and lower portions being located upstream and downstream respectively relative to the distributor;
• an upper inner tube positioned at least partially upstream from the distributor;
• a lower inner tube positioned at least partially downstream from the distributor;
• a connecting tube for directing the gas to the upper portion;
• an internal support assembly for supporting the body, the internal support assembly comprising:
• an internal tube positioned inside the body and engaged with at least a part of the lower inner tube;
• at least one collar positioned between the internal tube and the upper portion, such that the internal support assembly supports the body upstream and downstream relative to the distributor;
• a lower o-ring gland positioned proximal to the lower portion, to permit movement of the internal tube and the primary tip relative to each other due to thermal expansion at least partially in an axial direction substantially parallel to the axis;
• an upper o-ring gland positioned proximal to the upper portion, to permit movement of the upper inner tube and the connecting tube relative to each other due to thermal expansion at least partially in the axial direction;
• the upper inner tube comprising:
• an upstream portion proximal to the upstream end, the upstream portion being substantially cylindrical and having outer and inner diameters;
• a downstream portion proximal to the distributor, the downstream portion having an outer diameter larger than the outer diameter of the upstream portion and an inner diameter larger than the inner diameter of the upstream portion;
• a connecting portion connecting the upstream and downstream portions;
• the internal tube comprising an outer diameter smaller than the inner diameter of the downstream portion of the upper inner tube such that an annulus is defined between the internal tube and the downstream portion of the upper inner tube;
• the annulus being in fluid communication with said ports;
• and
• said at least one collar comprising at least one aperture therein to permit said second part of the gas to flow therethrough.