High temperature desulfurization using a new macroporous lime particle

高温脱除H2S是发展IGCC和Topping-Cycle等先进电厂的关键技术。直径约1mm的石灰颗粒是脱硫的候选吸附剂，但由于CaO颗粒只有微孔，只能利用颗粒的外表面。当CaO转化为CaS时，微孔容易被堵塞，从而阻止H_2S渗透到颗粒内部。如果制备具有大量大孔的石灰颗粒，则可以克服这一缺点。从这个角度出发，我们尝试用石灰或Ca(OH)_2-水泥浆制备几种大孔CaC，方法如下：(a)在10um下粉碎的石灰颗粒，在900℃的蒸汽中受压烧结10min。C;(b)将Ca(OH) 2-水浆料与几种有机酸的混合物加热至900℃。C;(c)在10p下粉碎的石灰颗粒。M被加热到900度。C和少量的CaCI_2。将制备的所有样品粉碎并过筛，得到直径为1mm的CaO颗粒。制备的CaO颗粒具有大量的大孔，孔径约为0.8 μ m。然后，用大孔CaO在900℃下对h2s和SO_2进行了脱硫。通过(a)和(b)方法制备的CaO颗粒在20分钟左右完全转化为CaS。脱硫速率与CaO颗粒的大孔体积有良好的相关性。说明该方法是制备具有高脱硫性能的大孔CaO颗粒的有效方法。

High temperature removal of H2S is a key technology for developing advanced power plants such as IGCC and the Topping-Cycle. The lime particle of about 1 mm in diameter is a candidate of adsorbents for the desulfurization, but only the outer surface of the particle can be utilized because the CaO particles has only micropores. The micropores are easily plugged when CaO is converted to CaS, preventing H_2S from penetrating into the interior of the particle. This drawback will be overcome if the lime particle with a large amount of macropore is prepared.From this viewpoint, we tried to prepare several macroporous CaC from lime or Ca(OH)_2-water slurry by the following methods : (a) the lime particles pulverized under 10um were pressed and sintered in steam for 10 min at 900 。C ; (b) mixture of Ca(OH) 2-water slurry and several organic acids were heated up to 900 。C ; (c) the lime particles pulverized under 10p.m were heated up to 900 。C with a small amount of CaCI_2. All the samples prepared were crushed and sieved to get CaO particles of 1mm in diameter. The CaO particles prepared had a large amount of macropore with around 0.8mum in pore diameter. Then, we performed desulfurization of H_2S and SO_2 using the macroporous CaO at 900 。C.The CaO particles prepared by methods (a) and (b) were converted to CaS completely within 20 min or so. The desulfurization rate was correlated well with the macropore volume in the CaO particle. Thus it was clarified that the proposed method was effective to prepare the macroporous CaO particle having high desulfurization performance.