Methane Purification Plant Using Hydrocarbon-Fueled CO2 Removal
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Solution Overview
Problem
Current methods for producing purified methane from natural gas and biogas are inefficient due to energy loss from pressure expansion and high operating costs associated with CO2 removal, particularly in small-scale liquefaction units, where heavy hydrocarbons and CO2 can cause equipment issues and require significant external energy for purification.
Innovation Solution
A plant and process that optimizes methane purification by using the pressure of the natural gas network and utilizing the energy from extracted heavy hydrocarbons to power CO2 removal, integrating a heavy hydrocarbon removal unit and a CO2 removal unit with a boiler to provide thermal energy for amine scrubbing, allowing for variable CO2 concentration adjustment in biogas purification to meet liquefaction standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If natural gas is expanded from high-pressure network pressure to low-pressure biogas level, then pressure compatibility for processing is improved, but energy loss increases
Solution Approach 1:
Instead of expanding natural gas from high pressure to low pressure, the invention inverts the approach by compressing biogas from low pressure to high pressure to match natural gas network pressure, thereby avoiding energy loss from expansion while achieving pressure compatibility for mixing and processing
2Manufacturing precision
If biogas is purified to remove CO2 using conventional methods, then methane quality is improved, but operating costs increase
Solution Approach 1:
The invention merges the CO2 removal process with the existing amine scrubbing infrastructure designed for natural gas, combining biogas purification with the same equipment and chemical system used for natural gas sweetening, thereby reducing operating costs while achieving required methane quality
Solution Approach 2:
The invention changes the operating parameters of the amine scrubbing system to accommodate biogas characteristics, adjusting amine concentration, temperature, and pressure conditions to optimize CO2 removal efficiency for biogas while maintaining cost-effectiveness
3Reliability
If heavy hydrocarbons are removed from natural gas, then equipment reliability is improved, but loss of valuable hydrocarbon substance occurs
Solution Approach 1:
The invention recovers heavy hydrocarbons removed during natural gas processing by injecting them into the biogas stream, where they serve as fuel for the CO2 removal process, thereby preventing substance loss while maintaining equipment reliability through effective heavy hydrocarbon removal
4Productivity
If biogas is compressed to high pressure for liquefaction, then liquefaction capability is improved, but energy consumption increases
Solution Approach 1:
The invention merges the biogas compression function with the natural gas high-pressure network infrastructure, utilizing the existing high-pressure natural gas system to provide both process pressure and energy, thereby enabling liquefaction capability while reducing additional energy consumption requirements
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 approach enhances energy efficiency by utilizing the natural gas network pressure and reduces operational costs by using the energy from heavy hydrocarbons for CO2 removal, optimizing the purification process for both natural gas and biogas to achieve high-quality methane production.
Implementation Method 1
a heavy hydrocarbon removal unit (3) comprising a first inlet (4) intended to be connected to a gas source (2) comprising natural gas, a first outlet (6) for gas purged of heavy hydrocarbons
Implementation Method 2
a boiler (11) for producing heat by combustion of heavy hydrocarbons
Implementation Method 3
The CO2 removal unit comprises a first inlet (10) connected to the first outlet (6) of the heavy hydrocarbon removal unit (3), a first outlet (12) for gas of reduced CO2 content
Data Source
AI summary
A plant for production of purified methane from natural gas and biogas, having, arranged in series in a gas circuit, a heavy hydrocarbon removal unit and a CO2 removal unit. The plant includes a biogas purification unit having an inlet intended to be connected to a biogas source and a first purified biogas outlet connected to the first inlet of the CO2 removal unit, the biogas purification unit being configured to produce biogas or biomethane with a variable/defined CO2 concentration, anda boiler having a first inlet connected to the second outlet of the heavy hydrocarbon removal unit, the boiler being configured to produce a thermal power determined as a function of the amount of hydrocarbons removed and supplied by the heavy hydrocarbon removal unit, the boiler being fluidically connected to the CO2 removal unit to provide said unit with thermal energy produced for CO2 removal.