Abstract

The solvent scrubbing method is one of the promising technologies to capture CO₂ from flue gas. In this technology, CO₂ is absorbed from flue gas using a liquid solvent in an absorption column and subsequently, solvent and CO₂ are separated in a stripper column. The recovered solvent from the stripper unit is recycled to an absorption unit along with the makeup of the fresh solvent. Aqueous monoethanolamine (MEA) is widely used as the solvent in this method. The cost of solvent for continuous makeup in the absorber is one of the major operating costs. The goal of this study is to minimize the flow rate of the MEA stream to capture the specified amount of CO₂ from flue gas to reduce the operating cost. Various scenarios are simulated in commercial process plant simulator by varying the CO₂ loading in lean MEA stream and absorber height. Flue gas compositions are obtained from the Rocky Mountain Hunter Power Plant (coal-fired), Utah, USA. We have shown that more than 80% CO₂ is captured using absorber heights of 25–40 m and CO₂ loading in MEA of 0.2 and less using the minimum flow rate of MEA. An insignificant amount of MEA (<0.2%) is lost from the absorption and stripper units. Other than the purchasing cost of the solvent, operating costs related to pumping, cooling, handling, etc. can be significantly reduced using the method developed in this study.

摘要

溶剂洗涤法是从烟道气中捕获CO ₂的有前途的技术之一。在该技术中，CO ₂在吸收塔中使用液体溶剂从烟道气中吸收，随后溶剂和CO ₂在汽提塔中分离。从汽提装置回收的溶剂与新鲜溶剂的补充一起循环到吸收装置。水性单乙醇胺 (MEA) 在该方法中被广泛用作溶剂。吸收器中连续补充的溶剂成本是主要的运营成本之一。本研究的目标是最小化 MEA 流的流速以捕获指定量的 CO ₂烟气，降低运行成本。通过改变贫MEA流中的CO ₂负载和吸收器高度，在商业加工厂模拟器中模拟了各种场景。烟道气组合物从美国犹他州落基山亨特发电厂（燃煤）获得。我们已经表明，使用 25-40 m 的吸收器高度和0.2 或更低的 MEA 中的CO ₂负载，使用最小的 MEA 流速可以捕获超过 80% 的 CO ₂。从吸收和汽提装置中损失了微不足道的 MEA (<0.2%)。除了溶剂的购买成本外，使用本研究中开发的方法可以显着降低与泵送、冷却、处理等相关的运营成本。