Plant and method for carrying out an endothermic chemical process and for separating carbon dioxide from flue gas produced in the process
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Solution Overview
Problem
Existing endothermic chemical processes, such as those producing synthesis gas, face challenges in achieving high carbon capture rates from flue gases due to lower concentrations and pressures, leading to significant carbon dioxide emissions through smokestacks, and existing carbon capture unit revamps are costly and incompatible with existing plant designs.
Innovation Solution
A plant configuration that includes a reactor, waste heat recovery unit, flue gas compression unit, scrubber, absorption unit, and desorption unit, where the flue gas compression unit is arranged downstream of the waste heat recovery unit and upstream of the scrubber, allowing for reliable carbon dioxide capture and safe operation even in case of unit failures, and optionally integrating with existing smokestacks through conduit connections for efficient carbon dioxide separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a carbon capture unit is added to existing plants with smokestacks, then carbon dioxide capture rate is improved, but plant complexity and renovation cost increase
Solution Approach 1:
The flue gas compression unit is designed to serve dual functions: normally it compresses flue gas to the absorption unit for carbon dioxide capture, but in case of absorption unit failure or maintenance, it automatically switches to functioning as a smokestack for direct flue gas discharge. This multi-functionality eliminates the need for separate backup smokestack infrastructure and reduces overall plant complexity while maintaining carbon capture capability during normal operation.
Solution Approach 2:
The system utilizes pressure differential control to switch between operational modes. During normal operation, positive pressure differential drives flue gas through the absorption unit. When switching to smokestack mode, the pressure differential is reversed or equalized, allowing direct discharge. This parameter-based switching mechanism enables a single unit to perform multiple functions without complex mechanical switching devices.
2Reliability
If the flue gas compression unit is positioned upstream of the absorption unit, then operational reliability is improved, but energy consumption increases
Solution Approach 1:
The flue gas compression unit operates dynamically with variable speed drive capability, adjusting its compression output based on system requirements. During normal carbon capture operation, it provides necessary compression pressure. When switching to smokestack mode, the compression is reduced or eliminated entirely, minimizing energy consumption. This dynamic operation allows the system to maintain reliability while optimizing energy usage across different operational states.
Solution Approach 2:
The system incorporates feedback control mechanisms that monitor the operational status of the absorption unit and automatically adjust the compression unit's operation accordingly. When the absorption unit is functioning normally, compression is maintained at optimal levels. When failure or maintenance is detected, the feedback system switches the compression unit to smokestack mode, reducing energy consumption while maintaining system reliability through automatic failover.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enhances the reliability and safety of carbon dioxide capture, allows for efficient processing of flue gases, and reduces the need for separate smokestacks, achieving high carbon capture rates while minimizing operational disruptions and costs.
Implementation Method 1
a waste heat recovery unit in fluid connection with the combustion chamber, wherein the waste heat recovery unit is configured to capture heat from the carbon dioxide-containing flue gas stream
Implementation Method 2
a scrubber in fluid connection with the flue gas compression unit, wherein the scrubber is configured to at least partially remove sulphur oxides and/or nitrogen oxides from the carbon dioxide-containing flue gas stream by means of a scrubbing medium
Implementation Method 3
an absorption unit in fluid connection with the scrubber, wherein the absorption unit is configured to absorb carbon dioxide from the carbon dioxide-containing flue gas stream in a chemically acting absorption medium
Implementation Method 4
a desorption unit in fluid connection with the absorption unit, wherein the desorption unit is configured to release carbon dioxide from the carbon dioxide laden absorption medium
Data Source
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AI summary
The invention relates to a plant and a method for carrying out an endothermic chemical process, in particular for the production of synthesis gas, and for separating carbon dioxide from flue gas produced in the process. The plant according to the invention comprises a reactor comprising a combustion chamber in which a fuel is fired with an oxidant to form a carbon dioxide-containing flue gas stream. The plant further comprises a waste heat recovery unit in fluid connection with the combustion chamber, configured to capture heat from the flue gas stream. The plant further comprises a flue gas compression unit in fluid connection with the waste heat recovery unit, configured to increase the pressure of the flue gas stream. The plant further comprises a scrubber in fluid connection with the flue gas compression unit, configured to remove sulphur oxides and/or nitrogen oxides from the flue gas stream and to cool flue gas stream by means of the scrubbing medium. The plant further comprises an absorption unit in fluid connection with the scrubber, configured to absorb carbon dioxide from the flue gas stream in a chemically acting absorption medium to obtain a carbon dioxide laden absorption medium, and a desorption unit in fluid connection with the absorption unit, wherein the desorption unit is configured to release carbon dioxide from the carbon dioxide laden absorption medium.