绿色航空

王 璇

（湖北省荆州市松滋一中）

Green aviation

Most People who think about such things agree that replacing fossil fuels with renewable electricity,either directly or indirectly,is the best way to decarbonise(脱碳) industry,transport and the heating and cooling of buildings.But there are some holdout areas where this is hard.Aviation is one,because batteries and hydrogen (which could be made using renewable electricity) are too heavy to do the job easily.Hydrocarbon（碳氢化合物）aviation fuels are thus likely to be around for a while.

But such fuels need not be fossil.They might be synthesised from the CO2exhaust of various industrial processes.And a study just published inNature,by Aldo Steinfeld of ETH Zurich,a technological university in Switzerland,and his colleagues,shows how they might literally be harvested from thin air.

Dr.Steinfeld and his team designed and tested a system that,in fact,reimagines the natural process of photosynthesis.Plants take in atmospheric CO2and water and,with sunlight providing the energy,turn those raw materials into organic molecules（分 子）.And that is exactly what Dr.Steinfeld has done.

The process has three stages.The first absorbs CO2and water from the atmosphere using a so-called direct-air-capture device made by Climeworks,a spin-offof ETH founded by two of Dr.Steinfeld’s students.The CO2is reacted with basalt rock to dispose of it in the device.However,Dr.Steinfeld’s system makes use of it.

The second stage is the clever bit.It employs concentrated sunlight to heat a material called cerium oxide（二氧化铈）which,when so heated,reacts with both CO2and water.The reaction with CO2creates carbon monoxide.The one with water creates hydrogen.In both cases the by-product is oxygen,which is sent out into the atmosphere.But a mixture of carbon monoxide and hydrogen is a familiar one to industrial chemists.It is called syngas,and is widely used as a raw material to make other things.

The third part of the process is therefore to turn the syngas into organic molecules.For the hydrocarbons that make up aviation fuel an industrial chemist would normally turn to what is known as the Fischer-Tropsch process.For their demonstrator,the team chose another route,which led to methanol（甲醇）rather than hydrocarbons.But the general idea is the same.

The team’s demonstration device,which they installed on the roof of ETH’s Machine Laboratory Building,had a typical yield of 32ml of pure methanol per seven-hour day—tiny,but a clear proof of principle.A rough calculation suggests that substituting the world’s aviation-fuel market entirely in this way would need 45 000 km2of suitably sun-shining land.That sounds a lot,but is equivalent to about 0.5% of the area of the Sahara Desert.

Air-captured aviation fuel would certainly need its path to market smoothed by appropriate carbon taxes on the fossil variety,and possibly other measures.But Dr.Steinfeld’s device does seem to have demonstrated a convincing and potentially extendable way to go about making the stuff.

阅读小练

1.What does the last sentence in Paragraph 1 mean?

A.Aviation industry resist changing their fuels.

B.Renewable electricity is replacing fossil fuels.

C.Hydrocarbon aviation fuels are around the corner.

D.Traditional aviation fuels will be kept in use for a time.

2.Which is the correct order of the products in the reimagined process of photosynthesis?

a.methanol

b.syngas of carbon monoxide and hydrogen

c.CO2

d.organic molecules

A.abcd B.cdab C.bcda D.cbda

3.What does the author think of the air-captured aviation fuel?

A.Doubtful. B.Disapproving. C.Hopeful. D.Cautious.

4.What is the best title of the passage?

A.The preserve of hydrocarbon aviation fuels in aircrafts

B.A future of replacing fossil fuels with renewable electricity

C.The process of producing synthesised fuel from CO2exhaust

D.A way of turning atmospheric CO2and water into aircraft fuel

（答案见P48）

全篇译文

大多数思考这些问题的人都同意，用可再生电力直接或间接地取代化石燃料，是工业、交通和建筑供暖及制冷去碳化的最佳途径。但是，在有些领域，这是很难做到的。航空就是一个，因为电池和氢气（可利用可再生电力制造）太重，不容易完成工作。因此，碳氢化合物航空燃料可能还会存在一段时间。

但这种燃料不一定是化石燃料。它们可以从各种工业过程的二氧化碳废气中合成。瑞士科技大学苏黎世联邦理工学院的Aldo Steinfeld 和他的同事刚刚在《自然》杂志上发表的一项研究表明，它们可能确实可以从稀薄的空气中提取出来。

Steinfeld 博士和他的团队设计并测试了一个系统，从本质上讲，该系统重新构想了光合作用的自然过程。植物吸收大气中的二氧化碳和水分，并在阳光的照射下提供能量，将这些原料变成有机分子。而这正是Steinfeld 博士所做的。

该过程分为三个步骤。第一步使用Climeworks 公司制造的所谓直接空气捕捉装置从大气中吸收二氧化碳和水分，Climeworks 公司是由Steinfeld 博士的两名学生创立的ETH 公司的衍生公司。在这个装置中，二氧化碳是与玄武岩反应来处理的。然而，Steinfeld 博士的系统利用了它。

第二步是最聪明的部分。它利用集中的太阳光来加热一种叫做氧化铈的材料，当它被加热时，会与二氧化碳和水发生反应。与二氧化碳的反应产生一氧化碳。与水的反应则产生氢气。在这两种情况下，副产品都是氧气，它们被排放到大气中。但是，一氧化碳和氢气的混合物是工业化学家们熟悉的一种（物质）。它被称为合成气，并被广泛用作制造其他东西的原料。

因此，该过程的第三步是将合成气变成有机分子。对于构成航空燃料的碳氢化合物，工业化学家通常会转向所谓的费希尔—特罗浦西工艺。对于他们的演示器，该团队选择了另一条路线，这生成了甲醇而不是碳氢化合物。但总体思路是一样的。

该团队的示范装置安装在ETH 机械实验大楼的屋顶上，每七小时的典型产量为32 毫升纯甲醇——（虽然很）小，但却是一个明确的原理证明。根据粗略计算，以这种方式完全取代世界航空燃料市场将需要45 000 平方公里的光照适宜的土地。这听起来很多，但相当于撒哈拉沙漠面积的0.5%左右。

从空气中获取的航空燃料肯定需要通过对化石品种征收适当的碳税，以及可能的其他措施，使其进入市场的途径更加顺畅。但是Steinfeld 博士的装置似乎已经展示了一种可靠的、可扩展的潜在方法来制造这种东西。

答案和解析

1.D 句意理解题。根据第一段第二、三句“But there are some holdout areas where this is hard.Aviation is one,because batteries and hydrogen (which could be made using renewable electricity) are too heavy to do the job easily.”可知，但是，在有些领域，这是很难做到的。航空就是一个，因为电池和氢气（可利用可再生电力制造）太重，不容易完成工作。由此可知，第一段最后一句表示碳氢化合物航空燃料可能还会存在一段时间。故选D。

2.D 推理判断题。通读第四至六段可知，该实验过程第一步收集二氧化碳；第二步生成一氧化碳，氢气和副产物氧气，其中氧气释放到空气中，一氧化碳和氢气生成合成气体；第三步由合成气体生成有机分子，最终生成甲醇。故选D。

3.C 观点态度题。根据最后一段最后一句“But Dr.Steinfeld’s device does seem to have demonstrated a convincing and potentially extendable way to go about making the stuff.”可知，但是Steinfeld 博士的装置似乎已经展示了一种可靠的、可扩展的潜在方法来制造这种东西。由此可推知，作者认为这种装置是有前景的。故选C。

4.D 标题概括题。通读全文尤其是第三段内容可知，Steinfeld 博士和他的团队设计并测试了一个系统，从本质上讲，该系统重新构想了光合作用的自然过程。植物吸收大气中的二氧化碳和水分，并在阳光的照射下提供能量，将这些原料变成有机分子。而这正是Steinfeld 博士所做的。由此可知，本文主要讲述的是一种将大气中的二氧化碳和水分结合起来制造飞机燃料的方法。故选D。