Process and apparatus for ortho-to-para hydrogen conversion

Claim 1

PROCESS FOR PRODUCING PARA-RICH LIQUID HYDROGEN COMPRISING THE STEPS OF PROVIDING COMPRESSED, PRECOOLED HYDROGEN GAS FEED AT BELOW 80*5. AND A T 20-200 ATMOSPHERES PRESSURE, AND CONTAINING AT LEAST 50% PARA HYDROGEN; THROTTLE EXPANDING SAID GAS FEED TO BELOW ABOUT 2 ATMOSPHERES PRESSURE THEREBY PARTIALLY LIQUEFYING SUCH FEED; PASSING A FIRST PORTION OF THE PARTIALLY LIQUEFIED FEED TO A CONVERSION ZONE, PASSING A SCOND PORTON OF THE PARTIALLY LIQUEFIED FEED TO A CONDENSATION ZOE AT LOWER PRESSURE THAN SAID CONVERSION ZONE; TRANSFERRING THE THROTTLE VAPOR OF SAID FIRST PORTION FROM SAID CONVERSION ZONE TO SAID CONDENSTION ZONE AND HEAT EXCHANGING SAID THROTTLED VAPOR WITH THE SECOND PORTION LIQUID FOR CONDENSATION THEREOF; RECYCLING THE CONDENSED THROTTLED FLUID TO SAID FIRST PORTION IN SAID CONVERSION ZONE; CONTACTING THE LIQUID HYDROGEN OF SAID FIRST PORTION WITH AN ORTHO-TOPARA CONVERSION CATALYST MASS IN SAID CONVERSION ZONE; SEPARATING THE VAPOR FORMED BY SUCH CONVERSION FROM TH CONVERTED LIQUID AND HEAT EXCHANGING THE CONVERSION VAPOR WITH SAID SECOND PORTION LIQUID IN SAID CONDENSATION ZONE, THEREBY CONDENSING SUCH VAPOR; RECYCLING THE CONDENSED CONVERSION FLUID TO SAID FIRST PORTION IN SAID CONVERSION ZONE; AND HEAT EXCHANGING THE PARA-RICH CONVERTED HYDROGEN LIQUID PRODUCT WITH AT LEAST PART OF THE LIQUID HYDROGEN SECOND PORTION BEING AT LOWER PRESSURE THAN THE PRODUCT, THEREBY SUBCOOLING THE PARA-RICH LIQUID HYDROGEN PRODUCT.