51 The stoichiometric ratio of oxygen needed in natural gas combustion is 32g(O2)/16g(CH4).
52 If the air used for combustion provides oxygen in slight excess of this ratio,virtually all the oxygen will combine with the fuel rather than with the nitrogen in the air.
53 In practice ,off-stoichiometric combustion is achieved by asjusting the air flow to the combustion chamber so that any persistent visible plume just disappears.
參考答案:51.气体自然燃烧所需要的氧气的细胞量比率是23g(O2)/16g(CH4).
52.如果用来燃烧的空气能提供轻微超过这个比率的氧，实际上所有的氧都将和核燃料而不是氮结合。
53。在实践中，无细胞燃烧是通过调整空气流动使之流向燃烧室以便任何存留的可视的羽状水柱消失来完成的。
(我化学不好，不了解这方面的术语，所以只能只翻译字面。)