选煤外文翻译-选煤概述和煤的可选性

44 附 录 一 英 文 资 料 及 中 文 翻 译 45 of is of or as it to a as a of of to of to of to is to of is OM is of of or is ”)” be to ) or of to ” () or to s by is by on of is of It is an of 2. of of is of or as it to a 46 (A its or we of 0 50 we in to by of as as in of as a of of to OM so be of it of in of to in to on a of A to to of to of to is to of is of of on is an of is OM by of as is of of or 47 is ”)” be to ) or of to ” () or to ,3 is of OM in to up of to A a of to is of or is by or of to a as by to is as of s by is by on is by on of is up of is of is by is of It is an of 48 to be at a at of is if of as of in of of As to of a by a of to a is at A a is . of as as an of tu of of a in of is is in is of is . by A of is of is to as to as to a of , 1. of 2. of 49 3. of be if it is to a 28m 0% of be at a 50 of is on of in to of a is on It is in a of of by or of is by of to At 1) is 1 in a (2) is on 73) of a in is by a of of or a as by of by on of 1%. n in on to be in a to by in A of is on be as of as a a if in is a in It an to in a in of of an in in of in to of a is on It is in a 51 of of by or of is by of to At 1) is 1 in a (2) is on 73) of a in is by a (1) 2) of 3) of of in is of of It to of in in of in be by of to or of of in in in of of of to OM to of a of on of 0 5 of to to or to As a of a to on a of at 5%20%. If a of to a in an of as 3o 0 in in in 0% at of a of in of be at 52 of of or by of in of a by of e. g., or to e. g., a as by of by on of 1%. of to to of , 5to 7to It is a to 53 选煤概述 和 煤的可选性 摘要 煤炭加工选煤概述简单说来，选煤就是把原煤（即开采后未经加工含有各种杂质的煤）。商品煤是具有一定质量规格的产品，它能满足燃烧，液化气化等方面所不断提高的技术要求。现在开采的煤是五千万到三亿五千万年前的植物沉积而成，所形成的水平层状物称之为煤层，厚度不一，从数英寸到数百英尺。煤层中经常夹杂着厚度不等的页岩，粘土砂岩，有时还夹杂 石灰岩等沉积岩。从选煤的角度来说，这些和煤结合在一起的夹杂物称之为杂质。三级加工 选别中等粒度（ 1/2 英寸 1/2 毫米）的原料煤，小于 1/2 毫米粒级的则归入精煤（大于 1/2 毫米）或送往他处。 原煤可选性的研究主要是为了决定在某一比重下可能获得的产品数量和洗选的难以程度，并确定入洗煤的粒度。如果把选煤看成是从一块块的煤中除区杂质，而不是根据成吨的煤去考虑问题，就能比较清楚的理解粒度分析的重要性。粒度越小，选煤难度越大，成本越高。在可选性研究的试验程序开始之前，通常是先取出经破碎达到规定粒度上限的煤样，然后用 各种筛子进行筛分。各粒级产物要分别存放，以便进行可选性评定。表 1 所示为入料粒度的典型分析。表中列出了各粒级产物的重量百分数灰分硫分和发热量，分本级和累计两项。先配好重液，准确调节其比重，然后对各粒级产物进行浮沉试验，从比重最小的重液开始。每一级重液中的浮起物要称记重量，下沉物移入较高比重的重液，依次进行，直到获得个级比重物为止。表 2 为表 1 中产物的浮沉实验结果。由于工业上处理的粒级范围较广，经常把某些粒级浮沉试验结果加以适当组合，形成综合结果。 近年来，由于支付选煤成本所需的额外费用不能在萧条的煤炭市场上回收 ，美国的现代化选煤厂一直处于停产状态。在竞争性的市场上，用户往往首先根据按能量计算最低价格（即每百万英热单位包括交货费用在内的价格）的方法判断他们是否要购买。其次是判断按煤的性质决定的使用价值。煤的性质比较复杂，它包括灰分，灰的组成及熔点，固定碳，硫分，破碎和磨碎特性等各项因素。考虑了这些因素以后，还会改变最初的判断，但按一般规律来说，只有在使用中如能明显地节约费用，才能认为选煤这项额外费用是合算的。 然而，热值并不是选煤中应加以控制的主要方面。它与灰分和水分呈近似的线性关 54 系，但是在原煤中大块岩石被拣除后， 产率和灰分之间变成非线性关系，一般的规律是降低灰分就要增加热值回收率的损失。选煤中的产率损失是影响选煤总成本的最大项。由于选煤厂的规模乃至基建投资是以处理原煤的能力为基础的，因此产率损失对投资费产生最直接的影响。虽然构成选煤厂的各个项目并非全部都直接涉及选煤设备的处理能力，但通常人们认为随着工厂规模增大，投资费反而减少。按惯例，还本期很长，一个燃煤的厂的还本期为 30。 关键词 ： 煤炭加工 选煤 原煤可选性 简单说来，选煤就是把原煤（即开采后未经加工含有各种杂质的煤）。商品煤是具有一定质量规格 的产品，它能满足燃烧，液化气化等方面所不断提高的技术要求。 现在开采的煤是五千万到三亿五千万年前的植物沉积而成，所形成的水平层状