改性CaCO_3代替Ca(OH)_2高温净化烟气中HCl气体的研究

Investigation of Gaseous HCl High Temperature Scrubbing from Incineration Flue Gas with Modified CaCO_3 Alternative to Ca(OH)_2

在分析CO2对Ca（OH）2吸收HCl气体影响的基础上，研究了CaCO3类吸收剂替代Ca（OH）2在高温下吸收HCl气体的可行性．研究表明：Ca（OH）2在高温干式净化HCl的过程中，很大一部分是以CaCO3的形式反应的．与普通CaCO3相比，经NaOH溶液改性的CaCO3具有更高的反应活性，在550～650℃的高温段内的反应率甚至优于Ca（OH）2，且在600℃下对应的HCl平衡体积分数与Ca（OH）2相当或更低；因此，可以替代Ca（OH）2用作焚烧烟气中HCl气体吸收剂．600℃是改性CaCO3取代Ca（OH）2的合适反应温度．

In this paper, firstly the influence of CO2 partial pressure on HCl dry scrubbing with Ca（OH）2 is studied, then two kinds of CaCO3 are investigated for their possibilities to substitute Ca（OH）2 as absorbents for removing HCl at high temperatures. The experimental results show that a large part of Ca（OH）2 will convert into CaCO3 when being sprayed into high temperature flue gases. Compared with normal CaCO3, modified CaCO3 treated by NaOH solution shows a better reactivity when reacting with HCI, its final conversion rate is even higher than that of Ca（OH）2 within 550 - 650 ℃. Additionally, modified CaCO3 corresponds to HCI equilibrium concentration equal to or even lower than that of Ca（OH）2. All of the results proves that the modified CaCO3 is a good alternative to Ca（OH）2 and 600 ℃ is an appropriate reaction temperature for HCl high temperature removal.