The adjusted costs for Absorber 3 were then scaled to generate Absorber 3S with a cross-section area and packed volume similar to Absorber 1. Scaling to a larger diameter and smaller packed volume reduces the heights of the packed beds, so the overall height (excluding the stack) is scaled proportionally to this reduction in packed height. The purpose of this scaling based on physical size is to provide an additional cost estimate for a similarly sized and similarly constructed absorber. It is not expected that the scaled Absorber 3S design would have comparable performance to the other absorbers. The cost is divided into three components: vessel shell (including platforming), packing, and other internals (supports, distributors, collectors, etc.). Each component cost is scaled using Equation . suggests scaling shell costs by weight using an exponent of approximately 0.6 for stainless steel columns. It is assumed that when scaling Absorber 3 to Absorber 3S the shell thickness remains constant. Therefore, scaling by shell surface area to the power 0.6 is equivalent to scaling by shell weight. The internals cost is arbitrarily assumed to be 60% packing and 40% other internals. Packing cost is assumed to scale linearly (exponent = 1.0) with packed volume. Other internals are scaled with cross-section area with an exponent of 1.1, as the cost of these items is expected to increase more than linearly based on prior experience. lists the details of each cost estimate and adjustments made to arrive at the costs of each design adjusted to equivalent scopes. Absorbers 1, 2B, and 3S are all equivalent in terms of crosssection area and packed volume. The estimated costs for these designs are $19.7MM, $18.2MM, and $14.9MM respectively.