Humidification-dehumidification systems and methods at low top brine temperatures

Abstract

Embodiments described generally relate to systems comprising a humidifier (e.g., a bubble column humidifier) and a heating device (e.g. a heat exchanger), and associated methods. In certain embodiments, the heating device heats a first liquid stream comprising a condensable fluid in liquid phase (e.g., water) and a dissolved salt (e.g., NaCl) to a relatively low temperature (e.g., about 90° C. or less) prior to the first liquid stream entering the humidifier through a main humidifier liquid inlet. In some cases, the system comprising the humidifier and the heating device requires only low-grade heat to operate, which may be advantageous due to the low cost and high availability of such heat.

What is claimed is: 
     
         1 . A humidifier system, comprising:
 a humidifier comprising a main humidifier liquid inlet, a main humidifier gas inlet, a main humidifier liquid outlet, an intermediate humidifier liquid outlet, a main humidifier gas outlet, and a plurality of stages, wherein the plurality of stages comprises a first stage, a last stage, and one or more intermediate stages positioned between the first stage and the last stage, wherein the intermediate humidifier liquid outlet is a liquid outlet of the first stage or one of the one or more intermediate stages; and   a first heating device, wherein a first liquid inlet of the first heating device comprises or is fluidically connected to the intermediate humidifier liquid outlet, and wherein a first liquid outlet of the first heating device comprises or is fluidically connected to the main humidifier liquid inlet, and   wherein the first liquid inlet of the first heating device is configured to receive a first liquid stream comprising a condensable fluid in liquid phase and a dissolved salt, and wherein the main humidifier gas inlet is configured to receive a gas stream comprising a non-condensable gas.   
     
     
         2 - 89 . (canceled) 
     
     
         90 . The humidifier system according to  claim 1 , wherein the humidifier is configured to produce a vapor-containing humidifier gas outlet stream enriched in the condensable fluid in vapor phase relative to the gas stream received by the main humidifier gas inlet. 
     
     
         91 . The humidifier system according to  claim 1 , wherein the humidifier is configured to produce a concentrated humidifier liquid outlet stream enriched in the dissolved salt relative to the first liquid stream received by the first heating device. 
     
     
         92 . The humidifier system according to  claim 1 , wherein the humidifier system forms part of a desalination system. 
     
     
         93 . The humidifier system according to  claim 1 , wherein the humidifier is a bubble column humidifier. 
     
     
         94 . The humidifier system according to  claim 1 , wherein:
 the first stage is the stage of the plurality of stages positioned in closest proximity to the main humidifier liquid inlet, and   the last stage is the stage of the plurality of stages positioned in closest proximity to the main humidifier liquid outlet.   
     
     
         95 . The humidifier system according to  claim 1 , wherein:
 the humidifier is configured to flow the first liquid stream in a first direction from the first stage to the last stage, and   the humidifier is configured to simultaneously flow the gas stream in a second direction from the last stage to the first stage.   
     
     
         96 . The humidifier system according to  claim 1 , wherein:
 the humidifier further comprises an intermediate humidifier liquid inlet, and   the intermediate humidifier liquid inlet is a liquid inlet of the first stage or one of the one or more intermediate stages of the humidifier.   
     
     
         97 . The humidifier system according to  claim 1 , wherein the humidifier receives the first liquid stream at a temperature of about 90° C. or less at the main humidifier liquid inlet. 
     
     
         98 . The humidifier system according to  claim 91 , wherein an extracted liquid stream exits the humidifier through the intermediate humidifier liquid outlet at an extracted liquid stream flow rate and the concentrated humidifier liquid outlet stream exits the humidifier through the main humidifier liquid outlet at a main humidifier liquid stream flow rate, wherein the extracted liquid stream flow rate is about 5% to 50% of the main humidifier liquid stream flow rate, when the humidifier system is in operation. 
     
     
         99 . The humidifier system according to  claim 91 , wherein an extracted liquid stream exits the humidifier through the intermediate humidifier liquid outlet at an extracted liquid stream flow rate and the concentrated humidifier liquid outlet stream exits the humidifier through the main humidifier liquid outlet at a main humidifier liquid stream flow rate, wherein the extracted liquid stream flow rate is about 105% to 150% of the main humidifier liquid stream flow rate, when the humidifier system is in operation. 
     
     
         100 . The humidifier system according to  claim 1 , further comprising a dehumidifier comprising a main dehumidifier gas inlet comprising or fluidically connected to the main humidifier gas outlet, and further comprising a main dehumidifier liquid inlet, a main dehumidifier gas outlet, and a main dehumidifier liquid outlet. 
     
     
         101 . The humidifier system according to  claim 100 , wherein the dehumidifier is configured to remove at least a portion of the condensable fluid in vapor phase from the vapor-containing humidifier gas outlet stream to produce a dehumidifier liquid outlet stream comprising the condensable fluid in liquid phase and a dehumidifier gas outlet stream lean in the condensable fluid in vapor phase relative to the vapor-containing humidifier gas outlet stream. 
     
     
         102 . The humidifier system according to  claim 100 , wherein the dehumidifier is a bubble column condenser. 
     
     
         103 . The humidifier system according to  claim 1 , wherein the first liquid inlet of the first heating device is fluidically connected to a source of the first liquid stream. 
     
     
         104 . The humidifier system according to  claim 1 , wherein the first heating device is a first heat exchanger. 
     
     
         105 . The humidifier system according to  claim 104 , wherein:
 the first heat exchanger comprises a first fluidic pathway and a second fluidic pathway,   the first liquid inlet of the first heat exchanger is a liquid inlet of the first fluidic pathway, and   the first liquid outlet of the first heat exchanger is a liquid outlet of the first fluidic pathway.   
     
     
         106 . The humidifier system according to  claim 105 , wherein the first heat exchanger is configured to transfer heat from a heating fluid stream flowing through the second fluidic pathway to a liquid stream flowing through the first fluidic pathway. 
     
     
         107 . The humidifier system according to  claim 106 , wherein the heating fluid stream comprises water. 
     
     
         108 . The humidifier system according to  claim 1 , wherein the first heating device is a heat collection device, an electric heater, or a furnace. 
     
     
         109 . The humidifier system according to  claim 100 , further comprising a second heating device fluidically connected to the first heating device and the dehumidifier. 
     
     
         110 . The humidifier system according to  claim 109 , wherein the second heating device is a second heat exchanger comprising a first fluidic pathway and a second fluidic pathway, wherein a liquid inlet of the second fluidic pathway of the second heat exchanger is fluidically connected to the main dehumidifier liquid outlet. 
     
     
         111 . The humidifier system according to  claim 110 , wherein a liquid outlet of the first fluidic pathway of the second heat exchanger is fluidically connected to an intermediate humidifier liquid inlet, wherein the intermediate humidifier liquid inlet is a liquid inlet of one of the one or more intermediate stages of the humidifier. 
     
     
         112 . The humidifier system according to  claim 1 , further comprising a first tank fluidically connected to the intermediate humidifier liquid outlet and the first liquid inlet of the first heating device. 
     
     
         113 . The humidifier system according to  claim 1 , wherein the condensable fluid comprises water. 
     
     
         114 . The humidifier system according to  claim 1 , wherein the non-condensable gas comprises air. 
     
     
         115 . The humidifier system according to  claim 1 , wherein the dissolved salt comprises NaCl.