초록 ▼

The present invention relates generally to processes and systems for recovering helium from low helium-containing feed gases (i.e., containing less than about 10 volume % helium and more typically, less than about 5% helium by volume). The present invention more particularly relates to processes and

The present invention relates generally to processes and systems for recovering helium from low helium-containing feed gases (i.e., containing less than about 10 volume % helium and more typically, less than about 5% helium by volume). The present invention more particularly relates to processes and systems for recovering helium from low helium-containing feed gases using temperature swing adsorption (TSA) systems and multiple (e.g. two) stage vacuum pressure swing adsorption (VPSA) systems. In preferred embodiments of the invention, the first stage VPSA system is configured to provide regeneration gas for the TSA system, and/or the VPSA second stage tail gas is recycled to the first stage VPSA system.

대표청구항 ▼

1. A process for the recovery of helium, the process comprising: introducing a helium-containing feed gas into a temperature swing adsorption system;pretreating the helium-containing feed gas in the temperature swing adsorption system to produce a helium-containing pretreated feed gas;treating the h

1. A process for the recovery of helium, the process comprising: introducing a helium-containing feed gas into a temperature swing adsorption system;pretreating the helium-containing feed gas in the temperature swing adsorption system to produce a helium-containing pretreated feed gas;treating the helium-containing pretreated feed gas in a stage one pressure swing adsorption system to produce a stage one helium-containing purified gas and a stage one tail gas; andtreating the helium-containing purified gas in a stage two pressure swing adsorption system to produce a helium-containing product stream and a stage two tail gas,wherein at least a portion of the stage one tail gas is introduced into the temperature swing adsorption system. 2. The helium recovery process of claim 1, wherein at least a portion of the stage two tail gas is introduced into the stage one pressure swing adsorption system. 3. The helium recovery process of claim 1, further comprising feeding at least a portion of the stage one tail gas into a first buffer tank and providing at least a portion of the stage one tail gas from the first buffer tank to the temperature swing adsorption system. 4. The helium recovery process of claim 1, further comprising feeding the helium-containing pretreated feed gas into a second buffer tank and providing the helium-containing pretreated feed gas from the second buffer tank to the stage one pressure swing adsorption system and further comprising feeding the helium-containing purified feed gas to a third buffer tank and providing the helium-containing purified feed gas from the third buffer tank to the stage two pressure swing adsorption system. 5. The helium recovery process of claim 1, wherein the stage one pressure swing adsorption system comprises a vacuum pressure swing adsorption (VPSA) system. 6. The helium recovery process of claim 5, wherein the stage one VPSA system includes four adsorption beds, each adsorption bed having at least one adsorbent contained therein. 7. The helium recovery process of claim 6, wherein each adsorbent bed in the stage one VPSA system includes at least a first adsorbent, a second adsorbent and a third adsorbent contained therein. 8. The helium recovery process of claim 7, wherein the first adsorbent in the stage one VPSA system comprises alumina contained proximate to a first end of each respective adsorbent bed, the second adsorbent in the stage one VPSA system comprises activated carbon positioned downstream of the alumina adsorbent in each respective bed and the third adsorbent in the stage one VPSA system comprises zeolite positioned downstream of the activated carbon adsorbent in each respective bed. 9. The helium recovery process of claim 6, wherein the helium-containing pretreated gas is processed in the stage one VPSA system to produce the helium-containing purified feed gas in a twelve-step cycle in which: Step123456789101112Bed 1AD1AD2/AD3/EQ1DNPPGEQ2DNBDPGEQ1UPEQ2UPPP1PP2(BD1)PP1PP2Bed 2BDPGEQ1UPEQ2UPPP1PP2AD1AD2/AD3/EQ1DNPPGEQ2DN(BD2)PP1PP2Bed 3EQ1DNPPGEQ2DNBDPGEQ1UPEQ2UPPP1PP2AD1AD2/AD3/(BD3)PP1PP2Bed 4EQ2UPPP1PP2AD1AD2/AD3/EQ1DNPPGEQ2DNBDPGEQ1UP(BD4)PP1PP2whereinAD1 = First Adsorption StepAD2/PP1 = Second Adsorption Step/First product pressurizationAD3/PP2 = Third Adsorption Step/Second product pressurizationEQ1DN = First Equalization Down or top-to-top bed equalizationPPG = Provide Purge GasEQ2DN = Second Equalization Down or bottom-to-bottom bed equalizationBD = BlowdownPG = PurgeEQ1UP = First Equalization Up or bottom-to-bottom bed equalizationEQ2UP = Second Equalization Up or top-to-top bed equalizationPP1 = First Product PressurizationPP2 = Second Product Pressurization. 10. The helium recovery process of claim 1, wherein the stage two pressure swing adsorption system comprises a vacuum pressure swing adsorption (VPSA) system. 11. The helium recovery process of claim 10, wherein the stage two VPSA system includes four adsorption beds, each adsorption bed having at least one adsorbent contained therein. 12. The helium recovery process of claim 11, wherein each adsorbent bed in the stage two VPSA system includes at least a first adsorbent, a second adsorbent and a third adsorbent contained therein. 13. The helium recovery process of claim 12, wherein the first adsorbent in the stage two VPSA system comprises alumina contained proximate to a first end of each respective adsorbent bed, the second adsorbent in the stage two VPSA system comprises activated carbon positioned downstream of the alumina adsorbent in each respective bed and the third adsorbent in the stage two VPSA system comprises zeolite positioned downstream of the activated carbon adsorbent in each respective bed. 14. The helium recovery process of claim 11, wherein the helium-containing purified gas is processed in the stage two VPSA system to produce the helium-containing product feed gas in a twelve-step cycle in which: Step123456789101112Bed 1AD1AD2/AD3/EQ1DNPPGEQ2DNBDPGEQ1UPEQ2UPPP1PP2(BD1)PP1PP2Bed 2BDPGEQ1UPEQ2UPPP1PP2AD1AD2/AD3/EQ1DNPPGEQ2DN(BD2)PP1PP2Bed 3EQ1DNPPGEQ2DNBDPGEQ1UPEQ2UPPP1PP2AD1AD2/AD3/(BD3)PP1PP2Bed 4EQ2UPPP1PP2AD1AD2/AD3/EQ1DNPPGEQ2DNBDPGEQ1UP(BD4)PP1PP2whereinAD1 = First Adsorption StepAD2/PP1 = Second Adsorption Step/First product pressurizationAD3/PP2 = Third Adsorption Step/Second product pressurizationEQ1DN = First Equalization Down or top-to-top bed equalizationPPG = Provide Purge GasEQ2DN = Second Equalization Down or top-to-bottom bed equalizationBD = BlowdownPG = PurgeEQ1UP = First Equalization Up or top-to-bottom bed equalizationEQ2UP = Second Equalization Up or top-to-top bed equalizationPP1 = First Product PressurizationPP2 = Second Product Pressurization. 15. The helium recovery process of claim 1, wherein the temperature swing adsorption system includes three adsorption beds, each adsorption bed having at least one adsorbent contained therein. 16. The helium recovery process of claim 15, wherein the at least one adsorbent selectively adsorbs at least one heavy contaminant in the helium-containing feed gas. 17. The helium recovery system of claim 16, wherein the at least one heavy contaminant in the helium-containing feed gas is selected from the group consisting of: C6+ heavy hydrocarbons, H2S, H2O and mixtures thereof. 18. The helium recovery process of claim 15, wherein the helium-containing feed gas is processed in the temperature swing adsorption system to produce the helium-containing pretreated feed gas in a three-step cycle in which: Step123Bed No. 1OnlineHeatingCooling(PB1)Bed No. 2CoolingOnlineHeating(PB2)Bed No. 3HeatingCoolingOnline(PB3) wherein Online is adsorption step, Heating is counter-current with respect to feed direction, and Cooling is co-current with respect to feed direction. 19. The helium recovery process of claim 15, wherein each adsorbent bed includes at least a first adsorbent and a second adsorbent contained therein. 20. The helium recovery process of claim 19, wherein the first adsorbent comprises alumina and the second adsorbent comprises at least one adsorbent selected from the group consisting of: silica gel, titanium silicates, aluminosilicates, ZSM5 supported on gamma alumina, alumina, activated carbon and treated activated carbon and clinoptilolite. 21. The helium recovery process of claim 20, wherein the first adsorbent comprises alumina and the second adsorbent comprises barium ion exchanged clinoptilolite. 22. A process for the recovery of helium, the process comprising: treating a helium-containing feed gas in a stage one pressure swing adsorption system comprising four adsorption beds (Bed 1 (BD1), Bed 2 (BD2), Bed 3 (BD3), Bed 4 (BD4)) to produce a stage one helium-containing purified feed gas and a stage one tail gas; andtreating the helium-containing purified feed gas in a stage two pressure swing adsorption system comprising four adsorption beds (Bed 5 (BD5), Bed 6 (BD6), Bed 7 (BD7), Bed 8 (BD8)) to produce a helium-containing product stream and a stage two tail gas,wherein the stage one pressure swing adsorption system to produce the helium-containing purified feed gas comprises a twelve-step cycle in which: Step123456789101112Bed 1AD1AD2/AD3/EQ1DNPPGEQ2DNBDPGEQ1UPEQ2UPPP1PP2(BD1)PP1PP2Bed 2BDPGEQ1UPEQ2UPPP1PP2AD1AD2/AD3/EQ1DNPPGEQ2DN(BD2)PP1PP2Bed 3EQ1DNPPGEQ2DNBDPGEQ1UPEQ2UPPP1PP2AD1AD2/AD3/(BD3)PP1PP2Bed 4EQ2UPPP1PP2AD1AD2/AD3/EQ1DNPPGEQ2DNBDPGEQ1UP(BD4)PP1PP2whereinAD1 = First Adsorption StepAD2/PP1 = Second Adsorption Step/First product pressurizationAD3/PP2 = Third Adsorption Step/Second product pressurizationEQ1DN = First Equalization Down or top-to-top bed equalizationPPG = Provide Purge GasEQ2DN = Second Equalization Down or bottom-to-bottom bed equalizationBD = BlowdownPG = PurgeEQ1UP = First Equalization Up or bottom-to-bottom bed equalizationEQ2UP = Second Equalization Up or top-to-top bed equalizationPP1 = First Product PressurizationPP2 = Second Product Pressurization,and wherein the helium-containing purified gas is processed in the stage two pressure swing adsorption system to produce the helium-containing product feed gas comprises a twelve-step cycle in which: Step123456789101112Bed 5AD1AD2/AD3/EQ1DNPPGEQ2DNBDPGEQ1UPEQ2UPPP1PP2(BD5)PP1PP2Bed 6BDPGEQ1UPEQ2UPPP1PP2AD1AD2/AD3/EQ1DNPPGEQ2DN(BD6)PP1PP2Bed 7EQ1DNPPGEQ2DNBDPGEQ1UPEQ2UPPP1PP2AD1AD2/AD3/(BD7)PP1PP2Bed 8EQ2UPPP1PP2AD1AD2/AD3/EQ1DNPPGEQ2DNBDPGEQ1UP(BD8)PP1PP2whereinAD1 = First Adsorption StepAD2/PP1 = Second Adsorption Step/First product pressurizationAD3/PP2 = Third Adsorption Step/Second product pressurizationEQ1DN = First Equalization Down or top-to-top bed equalizationPPG = Provide Purge GasEQ2DN = Second Equalization Down or top-to-bottom bed equalizationBD = BlowdownPG = PurgeEQ1UP = First Equalization Up or top-to-bottom bed equalizationEQ2UP = Second Equalization Up or top-to-top bed equalizationPP1 = First Product PressurizationPP2 = Second Product Pressurization.