Technology Overview
This invention increases the liquefaction efficiency of a process gas by routing a bypass portion of cold heat transfer fluid of an active magnetic regenerative refrigerator in counterflow through the process heat exchanger toward heat sink of the refrigerator. The invention calls for diverting a few percent of the heat transfer fluid flow from a cold side of a demagnetized regenerator into the bypass channel of a process heat exchanger. Simultaneously, the process gas flow is continuously introduced into an adjacent channel of the process heat exchanger at a first hot inlet temperature whereby the bypass heat transfer fluid and the process gas in their respective channels are in excellent thermal contact with each other. The process gas or liquid is continuously cooled by the bypass flow to a first cold exit temperature of the process heat exchangers. By design the temperature difference between the bypass heat transfer first cold inlet temperature and the process gas first cold exit temperature is kept small, i.e. 1 to 2 kelvin throughout the entire hot to cold length of the process heat exchanger.
Advantages
This invention and patent are applicable for liquefying several gases, such as hydrogen, methane, air, and helium as well as other gases that require cryogenic conditions to liquefy. Perhaps most important, this invention significantly improves the efficiency to make liquid hydrogen, the most energy intensive gas to liquefy. Doubling the liquefier efficiency is possible with properly designed active magnetic regenerative liquefiers. For storage and delivery, liquid hydrogen and its higher energy density are the superior choice relative to other hydrogen storage methods such as compressed hydrogen. The technology described in this patent has the promise to significantly reduce the delivered cost of hydrogen fuel. Broad use of inexpensive hydrogen as a fuel or energy carrier will help provide better energy security; return major economic, environmental, and health benefits; and help minimize climate-change impacts related to greenhouse-gas emissions from energy use.
A relatively small number of hydrogen liquefiers currently exist in the world. Most of them are large industrial plants used for non-transportation applications such as feedstock for crude oil refineries and ammonia fertilizer plants. Few commercial liquefaction facilities have been built with capacities for smaller quantities (several metric tons/day) because liquefier plant installed costs tend to increase sharply as the capacity decreases.
The major barriers to deployment of fuel-cell electric vehicles are lack of local supply and refueling infrastructure that has smaller-scale capacity. Cost-effective and efficient hydrogen liquefiers on this scale for such refueling supply and refueling stations do not exist. These two key barriers to rapid adoption of hydrogen fuels can be eliminated by development of highly efficient and low-cost small-scale liquefiers.
Advantages
- Highly efficient liquefier technology that applies to any fuel gas or industrial gas that benefits from higher volumetric energy density in liquid form for storage, transport, and delivery
- Large impact on liquefying hydrogen or helium that have very large energy input per unit capacity compared to other cryogens such as liquid natural gas or air.
- Fills a technology gap in the energy supply chain for hydrogen use in the transportation and electric power generation sectors.
- Enable use of one or zero-carbon fuels in energy supply chains to enable better energy security, as well as offer major economic, environmental, and health benefits while simultaneously reducing impact on climate-change of increased energy use
- Enables economic coupling of hydrogen into any realistic model of “sustainable carbon-hydrogen-electricity cycles” in an integrated and critical manner