HTC Solvent Reclaimer System at Searles Valley Minerals Facility in Trona, California

Abstract

Chemical solvents such as alkanolamines that are used for CO2 capture from flue gases are vulnerable to quality deterioration which causes a number of operational challenges due to the accumulation of degradation products and other types of impurities within the solvent. To maintain solvent absorption efficiency and avoid operating problems, it is important to continuously remove the accumulated contaminants from the solvent by including a reclaiming process within large commercial CO2 capture plants. The new HTC solvent reclaimer system, called delta Reclaimer, has been integrated within the 800 ton per day CO2 amine capture plant at the Searles Valley Minerals Facility (SVM) to remove the undesirable contaminants from a solvent slipstream and return the clean solvent back to solvent circulation in the CO2 plant. The detailed analysis of the feed stream, product stream and waste stream shows that the delta Reclaimer is capable of removing most of the undesirable impurities and restoring the solvent to its original purity at a high recovery rate and minimum energy consumption. At normal operating conditions the recovery rate of the MEA solvent reaches 98% and the steam consumption is about 1 lb steam (40 psig) per 1 lb of recovered solvent. Very concentrated waste is collected periodically while the reclaimer process is in continuous operation. This technique contributed to a huge reduction of the quantity of waste collected for disposal.

Practical experience in post-combustion CO2 capture using reactive solvents in large pilot and demonstration plants

“…On the whole, the operation of many of these pilot plants, demonstration plants and commercial plant have contributed to the wealth of knowledge on PCC by absorption using reactive solvents. It has created awareness on the need for optimization strategies that could be used to minimize heat duty for solvent regeneration, design to minimize plant size, effective and economic flue gas polishing strategies, development of online analytical methods Pouryousefi, 2015;Pouryousefi and Idem, 2008), effective reclaiming methods (Elmoudir et al, 2014), etc. Operational experience has also brought to light the need for a thorough understanding of environmental and safety implications in amine processes.…”

Density, Viscosity, Refractive Index, and Electrical Conductivity of Degraded Monoethanolamine Solutions at Standard Temperatures

“…The artificially degraded solvents were prepared by adding certain amounts of formic acid, acetic acid, and N -acetylethanolamine at an equivalent percentage of 1/3 each to simulate the degraded MEA solvents. The range of the total degradation products’ mass fraction ( M DP /( M amine + M water + M DP )), w DP = (0 to 0.020), was selected based on the maximum expected level of HSS contamination found in a typical CO 2 capture plant where DP represents the degradation products …”

“…In a typical postcombustion CO 2 capture system, alkanolamine solvents such as monoethanolamine (MEA) are used to remove CO 2 from a flue gas stream. Exposed to impurities in the flue gas stream such as O 2 , NO x ,and SO x in the absorber and high temperature in the reboiler, alkanolamine solvents can experience chemical and thermal degradations. , …”

“…Exposed to impurities in the flue gas stream such as O 2 , NO x ,and SO x in the absorber and high temperature in the reboiler, alkanolamine solvents can experience chemical and thermal degradations. 1,2 The major kinds of degradation products which draw wide attention are heat-stable salts (HSSs) due to their impact on the plant performance, equipment, and operation. 3,4 These salts cannot be thermally broken down and thus fail to release the solvent back like amine−CO 2 salts (carbamates), directly leading to a reduced CO 2 absorption capacity of the solvent.…”

“…The range of the total degradation products' mass fraction (M DP /(M amine + M water + M DP )), w DP = (0 to 0.020), was selected based on the maximum expected level of HSS contamination found in a typical CO 2 capture plant where DP represents the degradation products. 2 2.3. Sample Analysis.…”