| 摘要 |
The present invention relates to a gas cleaning system for cleaning a gas stream containing carbon dioxide and sulfur dioxide, said gas cleaning system comprising: a pre-conditioning section (3); a CO2 removal stage (5); and a post-conditioning section (4); said pre-conditioning section comprising at least two gas-liquid contacting devices (19,20) arranged upstream of the CO2 removal stage (5) with respect to the flow direction of the gas; and said post-conditioning section comprising at least two gas-liquid contacting devices (30,31) arranged downstream of the CO2 removal stage with respect to the flow direction of the gas. The present invention further relates to a method for cleaning a gas stream containing carbon dioxide and sulfur dioxide, said method including removing, at least partly, carbon dioxide from the gas stream in a carbon dioxide removal step by bringing the gas stream into contact with a liquid comprising ammonia; contacting the gas stream with liquid in at least two steps upstream of the carbon dioxide removal step; and contacting the gas stream with liquid in at least two steps downstream of the carbon dioxide removal step. |
| 主权项 |
1. A method for cleaning a gas stream containing carbon dioxide and sulfur dioxide, said method including removing, at least partly, carbon dioxide from the gas stream in a carbon dioxide removal step by bringing the gas stream into contact with a liquid comprising ammonia such that the gas stream is depleted in carbon dioxide and enriched in ammonia, said method comprising the steps of:
a) bringing the gas stream into direct contact with a liquid stream in a first upstream gas-liquid contacting device upstream of the carbon dioxide removal step, cooling the gas stream, and absorbing into the liquid at least a part of the sulfur dioxide of the gas stream such that the gas stream is depleted in sulfur dioxide and said liquid stream is enriched in sulfate, b) bringing the gas stream depleted in sulfur dioxide into direct contact with a liquid stream in a second upstream gas-liquid contacting device upstream of the carbon dioxide removal step, cooling the gas stream, and absorbing into the liquid at least a part of the sulfur dioxide of the gas stream such that the gas stream is depleted in sulfur dioxide and said liquid stream is enriched in sulfate, c) removing, at least partly, carbon dioxide from the gas stream by bringing the gas stream depleted in sulfur dioxide into contact with a liquid comprising ammonia such that the gas stream is depleted in carbon dioxide, d) bringing the gas stream depleted in carbon dioxide into contact with a liquid stream enriched in sulfate in a first downstream gas-liquid contacting device downstream of the carbon dioxide removal step, cooling the liquid stream, and absorbing into the liquid at least a part of the ammonia of the gas stream such that the gas stream is depleted in ammonia and said liquid stream is enriched in ammonia, e) bringing the gas stream depleted in ammonia into contact with a liquid stream enriched in sulfate in a second downstream gas-liquid contacting device downstream of the carbon dioxide removal step, cooling the liquid stream, and absorbing into the liquid at least a part of the ammonia of the gas stream such that the gas stream is depleted in ammonia and said liquid stream is enriched in ammonia, f) withdrawing at least a portion of the liquid stream used in the second upstream gas-liquid contacting device and reusing the withdrawn liquid in a downstream gas-liquid contacting device and forwarding the remaining portion to the first upstream gas-liquid contacting device, or withdrawing at least a portion of the liquid stream used in the second downstream gas-liquid contacting device and reusing the withdrawn liquid in an upstream gas-liquid contacting device and forwarding the remaining portion to the first downstream gas-liquid contacting device. |
