綠色航空

王 璇

（湖北省荊州市松滋一中）

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(脫碳) 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?xì)浠衔铮゛viation 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（二氧化鈰）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.

閱讀小練

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

（答案見P48）

全篇譯文

大多數(shù)思考這些問題的人都同意，用可再生電力直接或間接地取代化石燃料，是工業(yè)、交通和建筑供暖及制冷去碳化的最佳途徑。但是，在有些領(lǐng)域，這是很難做到的。航空就是一個，因為電池和氫氣（可利用可再生電力制造）太重，不容易完成工作。因此，碳?xì)浠衔锖娇杖剂峡赡苓€會存在一段時間。

但這種燃料不一定是化石燃料。它們可以從各種工業(yè)過程的二氧化碳廢氣中合成。瑞士科技大學(xué)蘇黎世聯(lián)邦理工學(xué)院的Aldo Steinfeld 和他的同事剛剛在《自然》雜志上發(fā)表的一項研究表明，它們可能確實可以從稀薄的空氣中提取出來。

Steinfeld 博士和他的團(tuán)隊設(shè)計并測試了一個系統(tǒng)，從本質(zhì)上講，該系統(tǒng)重新構(gòu)想了光合作用的自然過程。植物吸收大氣中的二氧化碳和水分，并在陽光的照射下提供能量，將這些原料變成有機(jī)分子。而這正是Steinfeld 博士所做的。

該過程分為三個步驟。第一步使用Climeworks 公司制造的所謂直接空氣捕捉裝置從大氣中吸收二氧化碳和水分，Climeworks 公司是由Steinfeld 博士的兩名學(xué)生創(chuàng)立的ETH 公司的衍生公司。在這個裝置中，二氧化碳是與玄武巖反應(yīng)來處理的。然而，Steinfeld 博士的系統(tǒng)利用了它。

第二步是最聰明的部分。它利用集中的太陽光來加熱一種叫做氧化鈰的材料，當(dāng)它被加熱時，會與二氧化碳和水發(fā)生反應(yīng)。與二氧化碳的反應(yīng)產(chǎn)生一氧化碳。與水的反應(yīng)則產(chǎn)生氫氣。在這兩種情況下，副產(chǎn)品都是氧氣，它們被排放到大氣中。但是，一氧化碳和氫氣的混合物是工業(yè)化學(xué)家們熟悉的一種（物質(zhì)）。它被稱為合成氣，并被廣泛用作制造其他東西的原料。

因此，該過程的第三步是將合成氣變成有機(jī)分子。對于構(gòu)成航空燃料的碳?xì)浠衔?，工業(yè)化學(xué)家通常會轉(zhuǎn)向所謂的費希爾—特羅浦西工藝。對于他們的演示器，該團(tuán)隊選擇了另一條路線，這生成了甲醇而不是碳?xì)浠衔铩５傮w思路是一樣的。

該團(tuán)隊的示范裝置安裝在ETH 機(jī)械實驗大樓的屋頂上，每七小時的典型產(chǎn)量為32 毫升純甲醇——（雖然很）小，但卻是一個明確的原理證明。根據(jù)粗略計算，以這種方式完全取代世界航空燃料市場將需要45 000 平方公里的光照適宜的土地。這聽起來很多，但相當(dāng)于撒哈拉沙漠面積的0.5%左右。

從空氣中獲取的航空燃料肯定需要通過對化石品種征收適當(dāng)?shù)奶级?，以及可能的其他措施，使其進(jìn)入市場的途徑更加順暢。但是Steinfeld 博士的裝置似乎已經(jīng)展示了一種可靠的、可擴(kuò)展的潛在方法來制造這種東西。

答案和解析

1.D 句意理解題。根據(jù)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，在有些領(lǐng)域，這是很難做到的。航空就是一個，因為電池和氫氣（可利用可再生電力制造）太重，不容易完成工作。由此可知，第一段最后一句表示碳?xì)浠衔锖娇杖剂峡赡苓€會存在一段時間。故選D。

2.D 推理判斷題。通讀第四至六段可知，該實驗過程第一步收集二氧化碳；第二步生成一氧化碳，氫氣和副產(chǎn)物氧氣，其中氧氣釋放到空氣中，一氧化碳和氫氣生成合成氣體；第三步由合成氣體生成有機(jī)分子，最終生成甲醇。故選D。

3.C 觀點態(tài)度題。根據(jù)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 博士的裝置似乎已經(jīng)展示了一種可靠的、可擴(kuò)展的潛在方法來制造這種東西。由此可推知，作者認(rèn)為這種裝置是有前景的。故選C。

4.D 標(biāo)題概括題。通讀全文尤其是第三段內(nèi)容可知，Steinfeld 博士和他的團(tuán)隊設(shè)計并測試了一個系統(tǒng)，從本質(zhì)上講，該系統(tǒng)重新構(gòu)想了光合作用的自然過程。植物吸收大氣中的二氧化碳和水分，并在陽光的照射下提供能量，將這些原料變成有機(jī)分子。而這正是Steinfeld 博士所做的。由此可知，本文主要講述的是一種將大氣中的二氧化碳和水分結(jié)合起來制造飛機(jī)燃料的方法。故選D。