Pass-through Distillation (PTD) is a combination of two basic unit operations: evaporation and gas absorption. The latter includes the regeneration of the absorption fluid. That is the entire concept in a nutshell. Please click here to play a 3 minute explanatory video.
The simplicity of this arrangement should provide the reader with assurance that the concept is well grounded in trusted chemical engineering principles. There is nothing about connecting an evaporator to a gas absorption train (as opposed to a condenser) that should suggest any kind of technical risk. If one applied to patent the idea it would be rejected on the grounds that it is merely a combination of well-known prior art.
Patent examiners would also question the utility of the arrangement. After all, it uses more equipment to accomplish the same thing done by ordinary distillation. But ordinary distillation has two serious drawbacks: It tends to be a hot process and it uses a lot of energy. PTD, when properly configured, can alleviate both problems simultaneously.
In order to understand why this is so, it is necessary to examine how industrial distillation is carried out and how its limitations are determined. This material is covered in the section entitled “Background”.