Optimizing CO2 Capture, in Dehydration and Compression Facilities

Yet, now a days. Our earth still need our attention when global warming become a major event we are not abble to admit. The number of Carbon Dioxyde (CO2) raised in past few years. And it came from our uncontrolled consumption of Fuel. After a while, a ministry of energy taking more advantage to reduce this number start from natural gas exploration. The removal of CO2 by liquid absorbents is widely implemented in the yield of gas processing, chemical production, and coal gasification.

Many power plants are looking at post-combustion CO2 recovery to meet environmental regulations and to produce CO2 for enhanced oil recovery applications. The world energy demand will likely increase at rates of 10–15% every 10 years. This increase could raise the CO2 emissions by about 50% by 2030 as compared with the current level of CO2 emissions. The industrial countries (North America, Western Europe and OECD Paciic) contribute to this jump in emissions by 70% compared to the rest of the world, and more than 60% of these emissions will come from power generation and industrial sectors.

Despite the strong recommendations from certain governments, there are very few actual investments in CO2 capture facilities geared toward reducing greenhouse gas emissions mainly because of the high cost of CO2 recovery from lue gas. CO2 capture costs can be minimized, however, by designing an energy eficient gas absorption process. Based on the indings of recent conceptual engineering studies, HTC Purenergy estimated the production cost to be US$ 49/ton CO2 (US$ 54/ tonne CO2) for 90% CO2 recovery of 4 mole% CO2 content in the lue gas of NGCC power plants. A separate study showed the cost for 90% CO2 recovery of 12 mole% CO2 from a coal ired power plant to be US$ 30/ton CO2 (US$ 33/tonne CO2). The cost of CO2 recovery from coal power plant lue gas is substantially less than that of NGCC power plant lue gas due to the higher CO2 content in the feed.

The energy eficiency of a CO2 capture plant depends primarily on the performance of the solvent and optimization of the plant. In traditional lue gas plant designs, MEA was the primary solvent and was limited to 20 wt% to minimize equipment corrosion. Recent developments in controlling corrosion and degradation has allowed an increase in the solvent concentration to about 30 wt% thus decreasing the required  circulation and subsequent steam demand. A recent DOE study shows the steam consumption for an existing CO2 plant using 18 wt% MEA (Kerr McGee Process) is 3.45 lb of steam per lb of CO2 for amine regeneration. A modern process that uses 30 wt% MEA is expected to use 1.67 lb of steam per lb of CO2 for amine regeneration. The HTC formulated solvent is a proprietary blend of amines and has a lower steam usage than the conventional MEA solvent. Based on the material and energy balances for the plant designed in the recent study, the reboiler steam consumption is estimated at about 1.47 lb steam/lb CO2 using the proposed formulated solvent without implementing any split low conigurations. This is much less than the reported steam usage for the MEA solvent.

The design of a facility to capture 90% of the CO2 from the lue gas of a coal fired power plant is based on the speciied lue gas conditions, CO2 product speciications, and constraints. Using the ProMax® process simulation software from Bryan Research & Engineering, CO2 capture units can be designed and optimized for the required CO2 recovery using a variety of amine solvents. The following igure represents a simpliied process low diagram for the proposed CO2 Capture Plant.

The table below presents the main findings for CO2 capture from the coal ired power plant and the NGCC power plant, each designed to produce about 3307 ton per day (3,000 TPD metric). To produce the same capacity of CO2, only one train with smaller column diameters is required in the case of the coal power plant and two trains with larger column diameters are required in the NGCC Power Plant case. This is mainly due to processing a larger lue gas with lower CO2 content in the NGCC power plant. Consequently, a substantial reduction in the capital and production cost was reported for the coal ired power plant CO2 recovery facility.

Parameter	Coal Power Plant	MGCC Power Plant
CO2 Production Capacity, ton/day	3307	3307
CO2 Recovery, %	90	90
CO2 in flue gas, mol%	12	4
Number of Trains	1	2
Fluegas Rates, MMSCFD	528	920
Absorber Diameter, ft	32,8	39,4
Regenerator diameter, ft	19,7	19,7
Capital Cost, million US$	165	227
Operating Cost, million US$	25	51
Production Cost, US$/ton	30	49