Coproduction of liquefied natural gas and electric power with refrigeration recovery
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Solution Overview
Problem
Cryogenic refrigeration systems used in LNG production are energy-intensive and costly, with high capital expenditures, and current practices cool natural gas to low temperatures, resulting in minimal flash gas and boil-off gas generation, limiting efficiency and fuel utilization.
Innovation Solution
A system and method that utilize a heat exchanger to convert methane-containing vapor into liquid, where flash gas and boil-off gas are used as fuel to generate electric power, increasing the efficiency of LNG production by producing LNG at higher temperatures and simultaneously generating CNG and electric power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If natural gas is cooled to low temperatures in cryogenic refrigeration systems, then liquefaction is achieved, but energy consumption and capital costs increase significantly
Solution Approach 1:
The patent converts the previously wasted flash gas and boil-off gas into useful fuel for power generation. These gases, which were considered losses in traditional low-temperature liquefaction processes, are now utilized to generate electric power that drives the compression and refrigeration systems, creating a self-sustaining energy cycle that reduces external energy requirements.
Solution Approach 2:
The patent changes the operating temperature parameter from traditional low-temperature cryogenic liquefaction to higher-temperature liquefaction. By operating at elevated temperatures, the system generates sufficient flash gas and boil-off gas to power the process, fundamentally altering the energy balance and eliminating the need for external energy input while maintaining effective liquefaction.
2Temperature
If natural gas is cooled to low temperatures, then liquefaction is achieved, but capital costs increase due to expensive cryogenic equipment
Solution Approach 1:
The patent changes the operating temperature parameter from traditional low-temperature cryogenic liquefaction to higher-temperature liquefaction. By operating at elevated temperatures, the system generates sufficient flash gas and boil-off gas to power the process, fundamentally altering the energy balance and eliminating the need for external energy input while maintaining effective liquefaction.
3Productivity
If flash gas and boil-off gas are minimized through low-temperature cooling, then liquefaction efficiency is maintained, but fuel utilization is limited
Solution Approach 1:
The patent converts the previously wasted flash gas and boil-off gas into useful fuel for power generation. These gases, which were considered losses in traditional low-temperature liquefaction processes, are now utilized to generate electric power that drives the compression and refrigeration systems, creating a self-sustaining energy cycle that reduces external energy requirements.
Solution Approach 2:
The patent makes the flash gas and boil-off gas serve multiple functions: they provide refrigeration cooling in the heat exchanger and simultaneously serve as fuel for power generation. This multi-functionality maximizes the utility of byproduct gases and enables the system to both liquefy natural gas and generate electricity.
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 LNG production efficiency, maximizes the use of flash gas and boil-off gas, and addresses shifting fuel demands by producing LNG, CNG, and electric power from a single natural gas source, reducing energy consumption and capital costs.
Implementation Method 1
a heat exchanger configured to receive a methane-containing vapor and to convert the methane-containing vapor to a methane-containing liquid
Implementation Method 2
at least a portion of the first methane-containing vapor can condense to form a methane-containing liquid
Implementation Method 3
Heat can be exchanged from the first methane-containing vapor to a refrigerant fluid
Implementation Method 4
The power generation facility can be configured to receive the vapor comprising flash gas and/or boil-off gas, and to use the at least a portion of the vapor comprising flash gas and/or boil-off gas as fuel to generate electric power
Data Source
AI summary
Systems and methods for increasing the efficiency of liquefied natural gas (LNG) production, as well as facilitating coproduction of electric power, and compressed natural gas (CNG) are described. The systems and methods facilitate producing an intermediate LNG at a higher temperature, recovering refrigeration from flash gas and boil-off gas from the LNG, using flash-gas and boil-off gas as fuel to generate electric power, and providing LNG, CNG, and electric power to a vehicle fueling facility.