Question

what are solid-liquid, liquid -vapour, solid-vapour, solid-solution, gas-solution equilibrium explain with example​

Answer 1

Answer:

Reduction of CO2 emission is directly influenced by the efficiency with which we are able to capture carbon from flue gas and other gas mixtures related to energy generation, such as biogas, integrated gasification combined cycle gas, syngas, shift gas produced from steam reforming of natural gas or coal and natural gas1,2,3,4. Motivated by the staggering energy costs associated with these gas separations, finding the optimal material for a given separation has become a very active area of modern chemistry5,6,7. In particular, metal-organic frameworks (MOFs)8, a new class of crystalline nanoporous materials, are regarded as promising candidates for CO2 separations. MOFs are three-dimensional networks of metal clusters that are connected with organic linkers; by changing the metal and/or linker we can synthesize millions of different materials. Moreover, one can use this tunability to synthesize a material that has exactly the right pore volume, surface area and selectivity to efficiently separate CO2 (refs 9, 10, 11).The enthusiasm of the scientific community about MOFs and other nanoporous materials as solid adsorbents, however, does not yet resonate in the process engineering community12. To understand why not, consider a simple solid-adsorption separation process for carbon capture from flue gas. The first step involves an adsorber, containing the nanoporous material, which selectively adsorbs CO2 from the flue gas. Once the adsorber is saturated, regeneration is required, which is typically done by supplying heat (temperature swing adsorption) or applying vacuum (pressure swing adsorption) to the adsorbent. This process needs at least two columns, which alternate between the adsorption and the regeneration mode. Liquid absorption uses a similar process, replacing the nanoporous material with, for example, an amine solution. If we now compare one of the most promising MOFs with commercially available amine solutions, the energy required to regenerate the amine solutions is about one order of magnitude larger than the energy required to regenerate this MOF4,13. This is because in amine solutions, the CO2 is so strongly bound that one needs to boil the amine solution to reverse the chemical bonding; as the amine solution contains 70% water, most of this energy is actually used for boiling water. Nevertheless, liquid absorption is the current state-of-the-art process for carbon capture and, surprisingly, solid adsorption is not considered as such a promising alternative. The fact is due to two significant advantages of the use of liquids. First, the liquid phase allows us to use advanced heat integrations to recover a large fraction of the heat. In solid adsorption by contrast, efficient heat integration is very difficult. Without heat recovery, the energy efficiency of a solid-adsorption process will be low. Second, pumping allows liquid absorption to be carried out in a continuous process, whereas the solid adsorbent is typically used in a less efficient batch process. To take full advantage of the exciting developments in the field of MOFs, it is essential to remove these intrinsic difficulties related to a solid-adsorbent process.