HIGHLY ATTRITION RESISTANT AND DRY REGENERABLE SORBENTS FOR CARBON DIOXIDE CAPTURE

摘要

Disclosed herein is a dry regenerable sorbent for carbon dioxide present in fuel gases (syngases and coal gases containing hydrogen and carbon monoxide) produced by the combustion of a fossil fuel in industrial plants, including thermal power generation plants, before being released to the air atmosphere, by a dry regenerable sorbent technology. The sorbent is prepared in the shape of a semisphere by forming a green body using a spray drying technique such that it has suitable shape and particle size for a fluidized-bed process for CO₂ capture. The sorbent comprises an active component selectively reacting with carbon dioxide present in a gas stream to capture the carbon dioxide, a support necessary to improve the reactivity of the active component and to maintain the shape of the sorbent, and a binder capable of binding the active component to the support to impart sufficient mechanical strength to the sorbent. Further disclosed is a method for preparing the dry regenerable sorbent which comprises the steps of obtaining a slurry through formulation, mixing, comminution and dispersion of the sorbent raw materials, forming the slurry by spray drying to produce sorbent particles, and calcining the sorbent particles. In the step of obtaining a slurry, there is used organic additives (dispersant, a flow control agent, and an organic binder) necessary to obtain a well-dispersed, stable and free-flowing slurry in which the raw materials are present below a sub-micron level (nanosize). The organic additives are removed and decomposed through the calcining. The use of the hydrophilic and high specific surface area support allows the dry regenerable sorbent to have a high reactivity. The solid active component is used instead of a liquid amine used in a conventional wet carbon dioxide capture technology. In addition, the sorbent can be re-used through continuous sorption and regeneration processes. Furthermore, the sorbent can capture carbon dioxide from a large volume of flue gases discharged from thermal power generation plants in an efficient and economical manner. Therefore, the sorbent minimizes the release of carbon dioxide to the air atmosphere and thus contributes to the prevention of global warming.