Abstract:

In response of such problems as ammonia escape, high regeneration energy, low absorption rate in the late stage of carbon capture by ammonia, this paper presents two kinds of reinforced crystallization technologies based on solventing-out, respectively called mixed absorbent process and reinforced crystallization of carbonized aqueous ammonia. Reinforcing crystallization of aqueous ammonia of low carbonization degree can maintain average absorption rate at a high level and regeneration by desorbing crystal product can save regeneration energy. Ammonia of low carbonization degree is chosen as absorbent, which can solve the ammonia escape problem to some extent. In the two kinds of processes, the common point is that regeneration by desorbing crystal product replaces recycling of carbonized aqueous ammonia and consequently saves regeneration energy. These two new processes all adopt semi-continuous bubbling reactor, and their process route, absorption rate, crystallization yield, characteristics of crystal product are compared.

Key words: CO₂ capture, solventing-out, regeneration, crystallization, bubbling reactor

摘要：

针对目前氨法二氧化碳捕集技术中存在的氨逃逸、再生能耗高、反应后期吸收率低等问题, 提出了两种基于溶析法强化结晶的工艺, 分别为混合吸收剂法以及溶析法强化低碳化度氨水结晶工艺。低碳化度氨水结晶可以使吸收过程维持在较高的吸收速率, 采用晶体产物解析既可以实现再生能耗的降低又可以解除再生能耗对于氨水浓度的限制, 因此可选低浓度氨水作为吸收剂, 在一定程度上解决当前氨法脱碳中存在的问题。两种工艺均采用以晶体产物再生代替富液循环的再生方法, 大大降低再生过程中的能耗。两种新工艺均是采用半连续鼓泡反应系统进行的基础研究, 并从工艺路线、吸收效率、结晶收率、晶体产物特性等方面进行对比。

关键词: 二氧化碳捕集, 溶析法, 再生, 结晶, 鼓泡反应器