The way we normally recycle plastics is a downward spiral of waste and degraded materials, but there is another option – turning plastic back into the oil it was made from.

我们通常使用的塑料回收方法是废料和降解材料的恶性循环，但还有一种选择：将塑料还原成它的原材料石油。

There is one man-made material that you can find in the earth, the air and in the deepest ocean trenches. It is so durable that the majority of what has been created is still present in our ecosystem. Having made its way into the food chain, it permeates our bodies, flowing from our blood into our organs, even finding its way into the human placenta.

有一种你可以在土壤、空气、最深的海沟里找到的人造材料。由于特别耐用，所以至今留存在我们生态系统中。它进入食物链，渗入我们体内，通过血液流入我们器官，甚至进入人体胎盘。

It is of course plastic, and this durability is also what makes the material so useful. Cables stretching across ocean floors, water pipes under the ground and packaging that keeps food fresh all rely on this property.

它当然就是塑料，其耐用性也使该材料用处很大。纵横海底的电缆、地下水管、食物保鲜袋都依靠这种特性。

Efficiently recycling plastic by conventional means is notoriously difficult, and only 9% of all plastic ever made has been recycled into new plastics. But what if there was a way to turn plastic back into the stuff it was made from? The "next grand challenge" for polymer chemistry – the field responsible for the creation of plastics – is learning to undo the process by turning plastics back into oil.

利用常规手段高效回收塑料出了名地困难，只有9%的废塑料被回收变成新塑料。但如果有办法将塑料还原成它的原材料会怎么样？高分子化学领域——负责创造塑料——面临的“下一个重大挑战”是学会逆转该过程，将塑料还原成石油。
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This process – known as chemical recycling – has been explored as a viable alternative to conventional recycling for decades. So far, the stumbling block has been the large amount of energy it requires. This, combined with the volatile price of crude oil sometimes makes it cheaper to produce new plastic products than to recycle existing plastic.

这种工艺被称为化学回收法，作为替代常规回收法的可行方案已有几十年的探索历程。迄今最大的难点是消耗能量巨大，再加上原油价格波动剧烈，有时生产新塑料制品比回收废塑料更便宜。

Every year, more than 380 million tonnes of plastic is produced worldwide. That's about the same as 2,700,000 blue whales – more than 100 times the weight of the entire blue whale population. Just 16% of plastic waste is recycled to make new plastics, while 40% is sent to landfill, 25% to incineration and 19% is dumped.

全球每年生产3.8亿吨塑料，大约相当于270万头蓝鲸——是所有蓝鲸总重量的100多倍。只有16%的废塑料被回收加工成新塑料，40%被运往垃圾填埋场，25%被运往焚烧厂，19%被丢弃。

Much of the plastic that could be recycled – such as polyethylene terephthalate (PET), which is used for bottles and other packaging – ends up in landfill. This is often due to confusion about kerbside recycling or contamination with food or other types of waste.

大多数塑料可以被回收，例如聚对苯二甲酸乙二醇酯（PET）被用于生产瓶子和包装，最终进入垃圾填埋场。这通常是因为与街边的回收垃圾混合在一起，或者受到食物及其他类型废弃物的污染。

Other plastics – such as salad bags and other food containers – find their way to landfill because they are made up of a combination of different plastics that can't be easily split apart in a recycling plant. Litter dropped in the street and lightweight plastics left in landfill sites or illegally dumped can be carried by the wind or washed into rivers by the rain, ending up in the ocean.

其他塑料的归宿是垃圾填埋场，例如沙拉包装袋和其他食品容器，因为它们由不同的塑料构成，在回收厂无法被轻易分解。街道上的垃圾、垃圾填埋场里或者非法乱扔的轻质塑料可能被风吹跑，或者被雨水冲入河流，最终进入海洋。
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Chemical recycling is an attempt to recycle the unrecyclable. Instead of a system where some plastics are rejected because they are the wrong colour or made of composites, chemical recycling could see all types of plastic fed into an "infinite" recycling system that unmake plastics back into oil, so they can then be used to make plastic again.

化学回收旨在回收无法回收的废弃物。回收装置拒绝处理某些塑料，因为它们的颜色错误或者由复合材料构成，而化学回收通过一种“无限”回收装置处理所有类型的塑料，将其还原成石油，然后再次利用它来制造塑料。

The way plastic is currently recycled is more of a downward spiral than an infinite loop. Plastics are usually recycled mechanically: they are sorted, cleaned, shredded, melted and remoulded. Each time plastic is recycled this way, its quality is degraded. When the plastic is melted, the polymer chains are partially broken down, decreasing its tensile strength and viscosity, making it harder to process. The new, lower grade plastic often becomes unsuitable for use in food packaging and most plastic can be recycled a very limited number of times before it is so degraded it becomes unusable.

现有的塑料回收法更像是恶性循环，而不是无限循环。塑料通常依靠机械回收：分拣、清洁、粉碎、熔化、重塑。每次都以这种方式回收塑料，质量有所下降。当塑料被熔化时，高分子链发生部分断裂，抗张强度和粘性下降，增加了塑料的加工难度。重新加工的低级塑料一般不适合食品包装用途，大多数塑料在质量下降到无法使用之前，回收次数十分有限。

The emerging industry of chemical recycling aims to avoid this problem by breaking plastic down into its chemical building blocks, which can then be used for fuels or to reincarnate new plastics.

新兴的化学回收产业旨在解决这个问题，将塑料分解为化学成分，然后用于燃料或重新加工成塑料。

The most versatile version of chemical recycling is "feedstock recycling". Also known as thermal conversion, feedstock recycling is any process that breaks polymers down into simpler molecules using heat.

用途最广的化学回收是“原料回收”，也被称为热转换，利用热量将高分子分解为简单的分子。

The process is fairly simple – take a plastic drinks bottle. You put it out with your recycling for collection. It is taken, along with all the other waste, to a sorting facility. There, the rubbish is sorted, either mechanically or by hand, into different kinds of materials and different kinds of plastics.

过程相当简单——就拿塑料的饮料瓶来说，你把它丢进垃圾箱里等待收运。饮料瓶与其他废弃物被一同运往分拣设施，这里依靠机械设备或人力将垃圾分拣为各种材料和塑料。

Your bottle is washed, shredded and packed into a bale ready for transportation to the recycling centre – so far, the same as the conventional process. Then comes the chemical recycling: the plastic that formerly made up your bottle could be taken to a pyrolysis centre where it is melted down. Next it is fed into the pyrolysis reactor where it is heated to extreme temperatures. This process turns the plastic into a gas which is then cooled to condense into an oil-like liquid, and finally distilled into fractions that can be put to different purposes.

你的饮料瓶被清洗、粉碎、打包，准备运往回收中心——这些与常规流程一样。接下来是化学回收：饮料瓶的塑料会被运往热解中心熔化，然后放入热解反应器加热至极端温度。该过程使塑料变成气体，冷却后凝结成油状液体，最后蒸馏出不同用途的组分。

Chemical recycling techniques are being trialled across the world. UK-based Recycling Technologies has developed a pyrolysis machine that turns hard-to-recycle plastic such as films, bags and laminated plastics into Plaxx. This liquid hydrocarbon feedstock can be used to make new virgin quality plastic. The first commercial-scale unit was installed in Perth in Scotland in 2020.

世界各地都在试验化学回收技术。总部位于英国的“回收技术”公司研发出一种热解装置，将薄膜、塑料袋、层压塑料等难以回收的塑料加工成Plaxx，这种液态烃原料可被用于制造全新的优质塑料。2020年，苏格兰在珀斯安装了首台商业级热解装置。

The firm Plastic Energy has two commercial-scale pyrolysis plants in Spain and plans to expand into France, the Netherlands and the UK. These plants transform hard-to-recycle plastic waste, such as confectionery wrappers, dry pet food pouches and breakfast cereal bags into substances called "tacoil". This feedstock can be used to make food-grade plastics.

“塑料能源”公司在西班牙拥有两座商业级热解工厂，计划向法国、荷兰、英国扩张。这些工厂将糖果裹包机、干燥的宠物食品袋、早餐麦片包装袋等难以回收的废塑料加工成“tacoil”，这种原料可被用于制造食品级塑料。

In the US, the chemical company Ineos has become the first to use a technique called depolymerisation on a commercial scale to produce recycled polyethylene, which goes into carrier bags and shrink film. Ineos also has plans to build several new pyrolysis recycling plants.

美国化学公司Ineos首次大规模采用解聚技术生产回收的聚乙烯，被用于生产购物袋和可缩性薄膜。该公司还打算建造几座新的热解回收工厂。
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In the UK, Mura Technology has begun construction of the world's first commercial-scale plant able to recycle all kinds of plastic. The plant can handle mixed plastic, coloured plastic, plastic of all composites, all stages of decay, even plastic contaminated with food or other kinds of waste.

在英国，Mura Technology公司已开始建造全世界第一座回收各种塑料的商业级工厂，它能够处理复合塑料、彩色塑料、所有复合材料的塑料、所有降解阶段的塑料、甚至受到食物或其他废弃物污染的塑料。

Mura's "hydrothermal" technique is a type of feedstock recycling using water inside the reactor chamber to spread heat evenly throughout. Heated to extreme temperatures but pressurised to prevent evaporation, water becomes "supercritical" – not a solid, liquid, nor gas. It is this use of supercritical water, avoiding the need to heat the chambers from the outside, that Mura says makes the technique inherently scalable.

Mura公司的“水热”技术是一种原料回收法，利用反应器腔体内的水将热量均匀分布在整个反应器中。水被加热至极端高温，但在高压环境下避免蒸发，水处在“临界状态”——既不是固态、液态、也不是气态。据Mura公司介绍，利用临界水避免了从腔体外部加热，使该技术本身就能扩大生产规模。

"If you heat the reactor from the outside, keeping an even temperature distribution is really hard. The bigger you go the harder it gets. It's a bit like cooking," explained Mura's chief executive, Steve Mahon. "It's hard to fry a big steak all the way through but if you boil it, it's easy to make sure it's cooked evenly all the way through."

“如果你从反应器的外部加热，使温度均匀分布着实困难。反应器越大，难度越大，有点类似于做饭”，Mura公司总裁斯蒂夫·马洪说道。“一大块牛排很难彻底煎熟，但如果你把牛排放在水里去煮，那就很容易确保均匀彻底地煮熟”。

The plastic waste arrives on site in bales – contaminated, multi-layer plastic such as flexible films and rigid trays that would otherwise have gone to incineration or energy-from-waste plants. The bales are fed into the front-end sorting facility to remove any inorganic contaminants such as glass, metal or grit. Organic contaminants such as food residue or soil are able to pass through the process. The plastic is then shredded and cleaned, before being mixed with supercritical water.

塑料废弃物被打包运抵现场——受污染的复合层塑料原本会被运往焚化厂或“转废为能”工厂，诸如可缩性薄膜、刚性托盘。这些塑料被投入前端分拣设施，筛除所有的无机污染物，诸如玻璃、金属、沙砾。食物残渣或土壤等有机污染物能够通过这一流程。然后粉碎和清洗塑料，将它们与“临界水”相混合。
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Once this high-pressure system is depressurised and the waste exits the reactors, the majority of liquid flashes off as vapour. This vapour is cooled in a distillation column and the condensed liquids are separated on a boiling range to produce four hydrocarbon liquids and oils: naphtha, distillate gas oil, heavy gas oil and heavy wax residue, akin to bitumen. These products are then shipped to the petrochemical industry.

当这种高压装置被减压，废弃物被排出反应器时，大部分液体会闪蒸成蒸汽。蒸汽在蒸馏塔中被冷却，冷凝液在某一沸程内被分离，制成四种烃类液体和油：石脑油、馏分瓦斯油、重瓦斯油、与沥青类似的重蜡渣。这些产品被运往石油化工行业。

As with other feedstock techniques, there is no down-cycling as the polymer bonds can be formed anew, meaning the plastics can be infinitely recycled. With a conversion rate of more than 99%, nearly all the plastic turns into a useful product.

与其他原料技术一样，由于聚合物的键可以重新生成，所以不存在降级回收，也就是说塑料可以被无限回收。转化率高达99%以上，几乎所有的塑料都可以转化成有用的产品。

Mahon said: "The hydrocarbon element of the feedstock will be converted into new, stable hydrocarbon products for use in the manufacture of new plastics and other chemicals." Even the "fillers" used in some plastics – such as chalk, colourants and plasticisers – aren't a problem. "These drop into our heaviest hydrocarbon product, heavy wax residue, which is a bitumen-type binder for use in the construction industry."

马洪说：“原料中的烃类组分将被转化成新的、稳定的烃类产品，用于制造新塑料和其他化学制品”。甚至某些塑料使用的填充剂也不在话下，诸如滑石粉、染色剂、塑化剂。“这些被用于制造最重的烃类产品重蜡渣，它是一种应用于建筑业的沥青型黏结剂”。

The hot, excess gases generated during the process will be used to heat the water, increasing its energy efficiency, and the plant will be powered by 40% renewable energy. "We want to use as much renewable energy as possible and will be seeking, wherever practical, to aim for 100%," says Mahon.

在此过程中产生的过剩热气被用于给水加热，提高它的能效，工厂将使用40%的可再生能源。“我们想尽可能多地使用可再生能源，在可行的前提下，力求达到100%这个目标”，马洪说道。

Mura's Teesside plant, due for completion in 2022, aims to process 80,000 tonnes of previously unrecyclable plastic waste every year, as a blueprint for a global rollout, with sites planned in Germany and the US. By 2025, the company plans to provide one million tonnes of recycling capacity in operation or development globally.

Mura公司的“梯赛德”工厂预计于2022年竣工，目标是每年加工8万吨过去无法回收的废塑料，作为全球推广的蓝图，公司计划将在德国和美国建厂。预计到2025年，该公司计划在全球范围内提供100万吨投产或开发的回收能力。

"[Our] recycling of waste plastic into virgin-equivalent feedstocks provides the ingredients to create 100% recycled plastics with no limit to the number of times the same material can be recycled – decoupling plastic production from fossil resource and entering plastic into a circular economy," says Mahon.

“我们将回收的废塑料转化成相当于全新的原料，利用它制造完全可再生的塑料，原料的回收次数无限——塑料生产与化石资源分离，将塑料纳入循环经济”，马洪说道。

Scientists such as Sharon George, senior lecturer in environmental science at Keele University, have welcomed Mura's development. "This overcomes the quality challenge by 'unmaking' the plastic polymer to give us the raw chemical building blocks to start again," says George. "This is true circular recycling."

科学家对Mura公司的发展表示欢迎，诸如英国基尔大学的环境科学资深讲师莎伦·乔治。“这克服了质量上的挑战，将塑料聚合物恢复原状，为我们提供塑料再生的化学原材料”，乔治说道。“这是真正的循环回收”。

Yet in the past 30 years, chemical recycling has shown serious limits. It is energy-intensive, has faced technical challenges and proved difficult to scale up to industrial levels.

但在过去的30年里，化学回收暴露出严重的局限。能源消耗量大，面临技术挑战，后来证明难以达到产业化规模。
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In 2020, a report by the Global Alliance for Incinerator Alternatives (Gaia), a group of organisations and individuals who promote social movements to reduce waste and pollution, concluded that chemical recycling is polluting, energy intensive and prone to technical failures. The report concluded that chemical recycling was not a viable solution to the plastic problem, especially at the pace and scale needed.

全球焚化炉替代方案联盟（GAIA）由组织和个人组成，致力于推动旨在减少废弃物和污染的社会活动。2020年，该联盟的一篇报告得出结论：化学回收造成污染，能源消耗量大，容易出现技术故障。该报告得出结论称，化学回收不是解决塑料问题的可行方案，尤其是回收速度和规模。

Additionally, if the end product of chemical recycling is an oil used for fuel then the process does not reduce the need for virgin plastic, and burning such fuels would release greenhouse gases just as ordinary fossil fuels do.

另外，如果化学回收的制成品是用于制造燃料的油，那么对新塑料的需求不会减少，这种燃料就像普通化石燃料一样，燃烧时释放温室气体。

"Environmental NGOs are keeping a close eye on emerging recycling methods," says Paula Chin, sustainable materials specialist at the conservation organisation WWF. "These technologies are in their infancy and they are by no means the silver bullet solution to the plastic waste problem. We should focus on increasing resource efficiency as a way to minimise waste through greater reuse, refill and repair systems – not relying on recycling to be the saviour."

“环境非政府组织正在密切关注新出现的回收方法”，环保组织“世界自然基金会”的可持续材料专家保拉·钦说道。“这些技术尚处于发展初期，绝不是解决废塑料问题的灵丹妙药。我们应该注重提高资源的利用效率，通过更优秀的再利用、加注、维修装置尽可能地减少能源浪费——不能把回收当成救世主”。

But Mura argues that their plant will fill a much-needed niche. "[Chemical] recycling is a new sector, but the scale at which it is developing, specifically for Mura, shows both the urgent need for new technology to tackle the rising problem of plastic waste and environmental leakage, and an opportunity to recycle a valuable ready-resource, which is currently going to waste," Mahon says.

但Mura公司认为，他们的工厂将弥补一个需求巨大的缺口。“化学回收是一个新兴领域，但对于Mura公司来说，该领域的发展规模证明人们急需新技术来解决日益凸显的废塑料和环境泄露问题，也表明这是回收宝贵的现成资源的机遇，这些资源正在被白白浪费”，马洪说道。

Mura's process aims to complement existing mechanical processes and infrastructure, not compete with them, recycling materials that would otherwise go to landfill, incineration or into the environment. All the waste plastic they process will be made new plastics or other materials, none will be burnt for fuel.

Mura公司的回收法旨在与现有的机械回收法和基础设施形成互补，而不是竞争，回收原本进入垃圾填埋场、焚化厂、大自然的材料。他们加工的所有废塑料会被制成新塑料或其他材料，不会被用作燃料来燃烧。

Mura hopes its use of supercritical water for efficient heat transfer will allow them to scale-up to industrial levels, lowering energy use and costs. It could be a crucial factor for success where others have failed.

Mura公司希望利用临界水来实现高效热量传递，从而达到产业化规模，减少能源消耗和成本。这可能是成功的关键因素，也是其他企业失败的地方。

One of the main reasons chemical recycling has failed to take off so far has been financial collapse. In a 2017 report, Gaia noted multiple projects that had failed, including the Thermosext facility in Germany which lost more than $500m (£350m) over five years, the UK's Interserve which lost £70m ($100m) on various chemical recycling projects, and many other companies that faced bankruptcy.

化学回收迄今未能成功的一个主因是财务危机。2017年，全球焚化炉替代方案联盟（GAIA）的一份报告提到多个失败的项目，包括德国热分选设施，五年亏损5亿多美元（3.5亿英镑）；英国Interserve公司在多个化学回收项目上亏损7万千英镑（1亿美元）；另外还有许多企业面临破产。
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Financial difficulty is something that has held back not just chemical recycling but all kinds of plastic recycling. "The economics do not stack up. Collecting, sorting and recycling packaging is simply more expensive than producing virgin packaging," says Sara Wingstrand, New Plastics Economy Project Manager at the Ellen MacArthur Foundation.

财务困境不仅对化学回收，而且对所有类型的塑料回收都构成阻碍。“经济效益不划算。收集、分拣、回收包装比生产新包装还贵”，艾伦麦克阿瑟基金会的新塑料经济项目负责人莎拉·温斯特兰德说道。
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Wingstrand says the only path to "dedicated, ongoing and sufficient funding at scale" for recycling is through mandatory, fee-based Extended Producer Responsibility schemes. These would see all industries that introduce plastic contributing funding to collect and process their packaging after its use. "Without them, it is very unlikely recycling of packaging will ever scale to the extent required," says Wingstrand.

温斯特兰德表示，塑料回收要想获取“专项、可持续、充足的资金，唯一道路是采取强制性、收费制的生产者延伸责任计划，所有行业利用塑料捐助基金来收集和加工废弃包装。“没有生产者延伸责任计划，包装回收永远达不到所需规模”，温斯特兰德说道。
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But Mahon believes a system like Mura's is another way to shift the balance sheets in favour of plastic recycling by producing an oil that can be sold at a profit. Mura has recently announced partnerships with the plastic manufacturers Dow and Igus GmbH, and the construction firm KBR.

但是马洪认为，像Mura公司的那种装置也是使资产负债表有利于塑料回收的一种方式，生产出来的油可以获利出售。Mura公司最近宣布与塑料制造商美国陶氏、德国易格斯、建筑公司KBR建立合作伙伴关系。

"The interesting thing here is that Mura can find value in plastics that aren't usually economically viable to recycle mechanically," says Taylor Uekert, researcher at the Cambridge Creative Circular Plastics Centre, University of Cambridge.

“有趣的是，Mura公司在塑料中找到的价值对于机械回收一般不具有经济可行性”，剑桥大学“剑桥创意性循环塑料中心”研究员泰勒·尤科特说道。
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Even with the ability to unmake all types of plastic so they can be reused again, it is unlikely to make all of the problems with plastic pollution go away. With so much ending up in landfill and the environment, plastic will continue doing what it was made to do – endure.

即使有能力将所有类型的塑料恢复原状，进而重复利用，也无法解决所有的塑料污染问题。那么多塑料最终进入垃圾填埋场和自然环境，塑料将继续履行它的使命——耐用。