Process enhancement in aqueous ammonia PCC using a direct contact condenser

Abstract

Aqueous ammonia‐based post‐combustion carbon capture (PCC) is a well recognized and leading technology for the reduction of CO2 emissions from coal‐fired power stations. Despite its many techno‐economic advantages over its counterparts, there are still a few major challenges that could prevent its large‐scale adoption. This model‐based study addresses the most common problems of solid precipitation at the stripper overhead and ammonia slipping with the product CO2. We propose using a direct contact condenser (DCC) to replace the conventional gas / liquid heat exchanger (HX) at the stripper overhead. Three scenarios were proposed and assessed for DCC configuration: open, closed, and combined DCC circuits. It was found that combined‐circuit DCC could better enhance the CO2 product's purity, bringing its temperature to the nominal target, and producing less condensate, which is diluted and easier for downstream integration. Most important, this configuration can effectively eliminate ammonia slipping in the product line and solid precipitation at the stripper overhead. Validating these improvements at our current pilot plant would bring tremendous benefits for the commercialization of this technology. © 2019 Society of Chemical Industry and John Wiley & Sons, Ltd.

Clathrating CO2 in a Supramolecular Granatohedron Cage with Noncovalent CO2–NH3 Interactions and High CO2 Capture Efficiency under Ambient Conditions

“…Nevertheless, guanidine regeneration requires temperatures above 120 °C for removal of lattice water and guanidinium carbonate decomposition . Ammonia solution, as a CO 2 capture sorbent, benefits from its high adsorption capacity and low regeneration energy but suffers from the high volatility of ammonia; hence, its practical application is restricted. − Aqueous solutions of NaOH, KOH, and Ca­(OH) 2 as CO 2 sorbents form carbonates with ultrahigh decomposition temperatures at 800–900 °C, making cycling difficult and inefficient. − Although the physical adsorption of CO 2 using highly porous materials shows great promise and advances, moisture interference and poor CO 2 selectivity restrict its application in industry …”

Response surface modelling of CO2 capture by ammonia aqueous solution in a microchannel

“…Ammonia‐based solvents have attracted an increased amount of attention as a CO 2 capture solvent. [ 19–24 ] The main advantages of ammonia‐based absorption are that there is no need for SO 2 , NO x , and O 2 removal as they do not degrade ammonia, larger CO 2 absorption capacity, and lower regeneration energy. [ 20,21 ] However, ammonia solution also possesses disadvantages.…”