Methods and systems for district energy CO2 support
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Solution Overview
Problem
Existing CO2-based district energy systems face inefficiencies in transporting CO2 from decentralized units due to the need for costly and energetically less efficient CO2 compressors, and potential safety risks from boiling liquid expanding vapor explosions (BLEVE) in liquid CO2 pipes, as well as challenges in separating CO2 and H2O from flue gases when using air for post-combustion.
Innovation Solution
The system employs a dual pipe configuration with a CO2 pipe and an external fluid line for transporting CO2 captured from flue gases at reduced pressure, and an additional O2 or O2-enriched mixture pipe to facilitate CO2 and H2O separation, using a cogeneration or heat pump unit with a quasi-concentric pipe arrangement to manage pressure and safety, and centralizing CO2 compression and purification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If CO2 compressors are used to transport CO2 from decentralized units, then CO2 transport is enabled, but cost and energy consumption increase significantly
Solution Approach 1:
The patent extracts the compression function from decentralized locations and centralizes it at a single location. Instead of having multiple distributed CO2 compressors at various decentralized units, the system collects CO2 at reduced pressure through the fluid line and performs centralized compression only where needed, eliminating redundant compression operations and reducing overall energy consumption.
Solution Approach 2:
The patent merges multiple CO2 collection functions into a single centralized compression system. The fluid line network consolidates CO2 from multiple decentralized sources, and a single centralized compressor handles all compression needs, combining what would otherwise be separate compression operations into one efficient system.
2Productivity
If liquid CO2 pipes are used for district heating, then heat transport efficiency is improved, but safety risks from BLEVE increase
Solution Approach 1:
The patent nests the liquid CO2 transport pipe within the external fluid line that contains vapor CO2 at reduced pressure. This nested configuration provides an additional safety layer where the outer vapor line contains any potential liquid CO2 leaks, preventing BLEVE conditions while maintaining efficient liquid CO2 heat transport in the inner pipe.
Solution Approach 2:
The vapor CO2 in the external fluid line acts as an intermediary safety barrier between the liquid CO2 in the inner pipe and the external environment. This intermediary layer prevents direct exposure to high-pressure liquid CO2, eliminating BLEVE risks while allowing efficient heat transport through the liquid CO2 pipe.
3Quantity of substance
If air is used for post-combustion to increase CO2 concentration, then CO2 separation is facilitated, but separation efficiency decreases due to nitrogen presence
Solution Approach 1:
Instead of trying to remove nitrogen from air to improve separation efficiency, the patent inverts the approach by accepting air's nitrogen content and using alternative methods (such as membrane separation or chemical absorption) that can effectively separate CO2 from the nitrogen-containing flue gas, achieving high separation efficiency despite the presence of nitrogen.
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 reduces the need for decentralized compressors, minimizes BLEVE risks, and enhances CO2 and H2O separation efficiency, resulting in economic and energetic gains, while enabling efficient CO2 transport and utilization in district heating and cooling systems.
Implementation Method 1
the fluid line is prefilled with CO2 at relatively reduced pressure, i.e. at a lower pressure than the pressure in said CO2 pipe
Implementation Method 2
the fluid line may be advantageously used for the transport of the CO2 captured from the flue gas produced by said unit(s)
Implementation Method 3
provide O2 or a O2 enriched mixture without nitrogen to said cogeneration unit or to a post-combustion unit, in a way to increase the concentration of CO2 and H2O in the flue gases and therefore to facilitate their separation
Data Source
AI summary
The invention concerns a district energy system comprising: —at least one cogeneration or heat pump unit —a first pipe system for district heating and/or cooling consisting of at least one liquid or vapor CO2 pipe; characterized by the fact that is also comprises a second pipe system consisting of at least one fluid line for the transport of CO2 or O2. The invention also relates to the use of a district energy system comprising: —at least one cogeneration or heat pump unit, —a first pipe system, —a second pipe system; characterized by the fact that that liquid or vapor CO2 is used in the first pipe system for district heating and/or cooling and that a fluid of CO2 or O2 is used in the second pipe system.