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美国的碳捕集技术可以追溯到 20 世纪 70 年代，当时这些技术用于去除气流中的 CO ₂，​​从而提高二叠纪盆地天然气和 EOR 的价值。

时代在变。

尽管如今碳捕获仍然普遍用于帮助提高石油产量，但随着世界致力于减少温室气体排放，重点正在转向储存捕获的碳。

“我们不是试图满足天然气产品规格，而是确定其他富含 CO ₂的来源，并尝试去除 CO ₂以确保其永远不会进入大气中，”Jeff Guenther，项目开发总监霍尼韦尔的碳捕获和蓝色氢，告诉哈特能源公司。“美国是这一领域的领导者”，在深层地质构造中提供了充足的存储能力，美国墨西哥湾沿岸已经建立了一些 CO _{2管道基础设施，中西部地区正在开发更多基础设施。”}

Hart Energy 与 Guenther 讨论了碳捕获和储存 (CCS) 技术，国际能源署表示需要这些技术才能实现净零排放目标。他称美国 CCS 的状况“相当好”，随着社会和企业认真对待减少排放，他对在包括欧洲在内的世界其他地区开发碳捕集项目产生了浓厚的兴趣。

埃克森美孚选择霍尼韦尔技术从位于德克萨斯州贝敦的一座新蓝氢工厂捕获 CO ₂ ，​​该工厂每年可储存 1000 万吨 CO _{2 。}

全球 CCS 研究所的数据显示，截至 2022 年 9 月，CCS 项目数量比去年同期增长了 44%，其中北美在 CCS 开发方面处于世界领先地位。然而，需要更大规模的部署才能实现净零排放目标。

为了篇幅和清晰度，本次采访经过编辑。

Velda Addison（弗吉尼亚州）：您认为碳捕获在全球范围内没有得到充分利用吗？鉴于降低排放和净零排放举措的推动，您如何看待这种变化？

Jeff Guenther (JG)：碳捕获和许多此类项目的关键是确实需要一些支持性政策来推动项目的推进。随着《抑制通胀法案》的通过，美国的政策非常明确，给了美国项目开发商信心。欧洲也有相当明确的政策。除此之外，还有很多问号。我同意这是一个未得到充分利用的工具，这是因为其他地区的政策在支持项目的清晰度和规模方面落后于欧洲和美国。”它正在发生变化，但速度稍慢，因为他们正在等待政策方面的明确性。从这个角度来看，它尚未得到充分利用，但全球似乎都认为这是一个减少排放的绝佳机会，特别是在那些在降低 CO ₂足迹的同时继续运营的选择有限的行业。

VA：在能源行业，我们经常听说 CCS 价格昂贵。是什么让它变得昂贵？

JG：昂贵是一个相对词，对吧？一切都需要与气候变化的影响进行比较，如果我们不采取任何行动，气候变化本身就会付出高昂的代价。那么为什么它贵呢？有大量CO ₂被排放到大气中。因此，当您谈论大型项目时，需要大量的资本投资来捕获这么多的 CO ₂。发电厂每年很容易排放超过一百万吨CO _{2 (mtpy)，在许多情况下超过3 mtpy CO 2}。这需要处理大量的气体和大量的CO ₂。

一旦您投资捕获它，您还需要某种类型的可用基础设施（最有可能通过管道）将 CO ₂转移到合适的封存地点。回答你的问题，当挑战很大时，解决方案也同样很大。

VA：考虑到一些项目最终未能捕获原计划那么多的 CO ₂，霍尼韦尔如何努力提高 CCS 对该行业的效率。有哪些关键技术可以帮助提高此类项目的成本和效率？

JG：在霍尼韦尔，我们拥有完整的技术解决方案组合，可用于在燃烧前和燃烧后应用中捕获碳。预燃烧应用的特点是高CO ₂浓度工艺流。通常，在氢气生产或天然气加工中，可以使用这些类型的流。它们可能含有 40% 至 60% 的 CO ₂ ，​​并且它们提供了以每吨一美元的低成本捕获 CO _{2的积极机会。}与燃烧后碳捕获相比，我们有一种化石燃料，在火焰加热器、涡轮机或锅炉中燃烧，我们捕获燃烧后气体或由此产生的烟道气中的CO ₂过程。这是世界上更大的市场机会，但处理起来更具挑战性，因为它的特点是 CO ₂浓度较低，这意味着以每吨美元计算，捕获 CO _{2 的成本更高。}

我们在这些应用中使用溶剂、吸收剂、膜和分馏技术。我们可以独立部署这些，也可以混合部署。” 在燃烧后方面，我们拥有先进的溶剂碳捕获技术，在市场上具有一些独特的优势。我们的溶剂具有非常高的传质速率，使得吸收设备比市场上以前的第一代溶剂更小。它也非常稳定，这意味着我们可以在更高的温度和压力下操作我们的工艺，这意味着我们可以在比市场上其他溶剂更高的压力下生产 CO _{2 。}这非常重要，因为当您谈论大量的 CO ₂时，每年产生100 万吨 CO _{2或更多，CO 2}需要被压缩到非常高的压力水平，通常约为 2,000 磅/磅平方英寸——便于运输和储存。当我们能够在更高的压力下生产 CO ₂时，实际上可以显着降低运输和储存之前压缩它的成本，通常在 30% 到 40% 的范围内，无论是在初始压力​​方面还是在该压缩的资本支出和年度运营费用。

VA：您提到了溶剂、吸收剂和分馏技术。霍尼韦尔是否发现对任何一项技术的需求量更大，或者是以上所有技术？

JG：有两个非常引人注目。_{在预燃烧领域，特别是在大规模氢气生产中，我们的 CO 2}分馏技术得到了很多积极的反馈，因为它的捕获成本较低，并且可以集成到氢气生产过程中达到极低的碳强度，并直接生产液态产品CO _{2 。}在燃烧后方面，市场上成熟的技术是基于溶剂的。因此，我们看到许多客户现在专注于评估溶剂来处理燃烧后烟气。

VA：您计划在埃克森美孚的蓝色氢项目中使用哪些具体技术？

JG：我们提供称为霍尼韦尔 UOP 多床 PSA 装置的氢气纯化设备。我们提供的脱水装置是霍尼韦尔 UOP Molsiv 装置、CO ₂分馏装置和氢膜装置。从本质上讲，该过程的工作原理是自动热重整装置产生富氢合成气。我们的氢气变压吸附装置将处理该气体并分离出高纯度氢气产品流。然后，它还将排出尾气流中的其他成分，包括 CO ₂，​​这些成分将被脱水和压缩并前往我们的 CO ₂分馏塔，在那里 CO ₂将被分离并生产为高纯度 CO ₂液体。_{然后，我们可以从 CO 2}分馏塔的顶部将气体发送至 PSA 和膜装置，以进一步回收氢气作为产品来源。该流中排出的气体将被回收回到 ATR，以便任何未转化的甲烷或一氧化碳将继续在装置中回收，从而将其转化为 CO ₂并通过我们的技术捕获。这导致碳强度非常低的氢产品。

总而言之，如果您将我们的产品想象成一个大盒子，气体将进入并被分成三股流：高纯度的氢气产品；高纯度液态CO ₂产品；和不含碳氢化合物的燃料流，其余部分在系统内循环利用。所有离开系统的CO ₂基本上都被捕获并储存。这就是该项目独特且令人兴奋的方面。我们可以推动氢气生产的低碳强度，为氢气成为燃料替代品和高价值商品提供机会。

VA：您是否发现越来越多的公司专注于封存CO ₂而不是利用它？捕获的碳有哪些用途？

JG：与我们交谈的大多数公司都专注于封存，尤其是在美国，因为我们拥有合适的地质环境来实现这一点。此外，在美国，有不同的激励水平。美国对永久储存的 CO ₂提供每吨 85 美元的税收抵免，对 EOR 使用每吨 60 美元的税收抵免。我们的大多数客户都希望将其永久存储在地下。大多数气候模型和市场模型都假设将捕获的大部分 CO _{2将被永久储存，因为一是这是防止其最终进入大气的可靠方法，二是，我们需要减少的 CO 2}量实在是太大了，以至于今天人们计划捕获的 CO 2 量实际上并不存在市场。

尽管如此，CO ₂可用于饮料和食品保鲜市场。我们还看到客户对使用 CO ₂作为燃料原料感兴趣。我们最近宣布了我们的电子精炼工艺技术，可以将 CO ₂和绿色氢气转化为甲醇，并最终转化为可持续航空燃料。因此，我们继续研究利用 CO ₂作为燃料的不同方法，以及生产社会所需的其他化学品的不同途径。但我们大多数客户的近期关注重点是永久储存 CO ₂ ，​​特别是在对其排放产生重大影响所需的数量方面。

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Carbon capture technologies in the U.S. date back to the 1970s when they were used to remove CO₂ from gas streams, improving the value of natural gas and EOR in the Permian Basin.

Times are changing.

Though carbon capture is still commonly used to help boost oil production today, focus is shifting to storing captured carbon as the world aims to reduce lower greenhouse gas emissions.

“Instead of trying to meet a natural gas product spec, we’re identifying other CO₂-rich sources and trying to remove the CO₂ to make sure it never gets into the atmosphere,” Jeff Guenther, project development director of carbon capture and blue hydrogen for Honeywell, told Hart Energy. “The U.S. is a leader in this space,” giving ample storage capacity in deep geological formations with some CO₂ pipeline infrastructure already in place in the U.S. Gulf Coast with more being developed in the Midwest.”

Hart Energy spoke with Guenther about carbon capture and storage (CCS) technologies, which the International Energy Agency said are required to reach net-zero emissions targets.  He called the state of affairs for CCS in the U.S. “quite good,” with strong interest in developing carbon capture projects in other parts of the world, including Europe, as society and corporations get serious about reducing emissions.

Exxon Mobil selected Honeywell technology to capture CO₂ from a new blue hydrogen plant at its Baytown, Texas, complex, with a capacity to store up 10 million metric tons of CO₂ per year.

Data from the Global CCS Institute show the number of CCS projects grew 44% through September 2022 compared to a year earlier, with North America leading the world in CCS development. However, more large-scale deployment is needed to hit net-zero emissions goals.

This interview was edited for length and clarity.

Velda Addison (VA): Do you consider carbon capture underutilized globally? How do you see that changing, given the drive to lower emissions and net-zero initiatives?

Jeff Guenther (JG): The key with carbon capture and a lot of these projects is there does need to be some supportive policy for projects to go forward. With the passage of the Inflation Reduction Act, the U.S. has very clear policy in place that gives project developers in the U.S. confidence. Europe also has pretty clear policy. Outside of that, there are many more question marks. I would agree it’s an underutilized tool, and it’s because policy in other regions are sort of lagging behind Europe and the U.S. in terms of clarity and magnitude of how they would support a project. … It is moving, but just at a slightly slower pace because they're waiting clarity on the policy side. It is underutilized from that standpoint, but there seems to be global vision that it is a strong opportunity to reduce emissions, especially in sectors that have limited options to continue to operate while lowering their CO₂ footprint.

VA: In the energy industry, we often hear that CCS is expensive. What makes it expensive?

JG: Expensive is a relative term here, right? Everything needs to be compared to the impact of climate change, which is expensive in its own right if we don’t do anything. So why is it expensive? There’s a lot of CO₂ being emitted into the atmosphere. So, when you’re talking about large-scale projects, there’s a large capital investment to capture that much CO₂. Power plants are easily emitting over a million tons of CO₂ per year (mtpy), in many cases over 3 mtpy CO₂. That's a lot of gas to be able to process and a lot of CO₂ to handle.

Once you make the investment to capture it, you also need some type of infrastructure available, most likely via pipeline, to move the CO₂ to a suitable sequestration site. To answer your question, when the challenge is big, the solution is equally big.

VA: How is Honeywell working to make CCS more efficient for the industry, given that some projects don’t end up not capturing as much CO₂ as originally planned. What are some of the key technologies to help improve cost and efficiency of these types of projects?

JG: At Honeywell, we have a full portfolio of technology solutions that we can use to capture carbon in both pre-combustion and post combustion applications. Pre-combustion applications are characterized as high CO₂ concentration process streams. Typically, in hydrogen production or in natural gas processing, these types of streams are available. They might have 40% to 60% CO₂ and they offer a positive opportunity to capture that CO₂ at a low cost on a dollar per ton basis. To contrast that with post combustion carbon capture, where we have a fossil fuel that’s being combusted in a fired heater, turbine or boiler, and we’re capturing the CO₂ in the post combustion gas or the resulting flue gas from that process. That’s the much larger market opportunity in the world, but it’s more challenging to treat because it’s characterized by lower CO₂ concentrations, which mean capturing that CO₂ becomes a higher cost on a dollar per ton basis.

We use solvents, absorbents, membranes and fractionation technology for these applications. We can deploy those independently or in hybrid schemes. … On the post combustion side, we have advanced solvent carbon capture technology that offers some unique advantages in the marketplace. Our solvent has a very high mass transfer rate, allowing the absorption equipment to be smaller than previous first-generation solvents on the market. It also is very stable, meaning that we can operate our process at a higher temperature and pressure, which means we can produce the CO₂ at a higher pressure than other solvents on the market. That’s really important because when you’re talking about large quantities of CO₂, a million tons of CO₂ per year or more, that CO₂ needs to be compressed to very high-pressure levels—typically around 2,000 pounds per square inch—to be transported and stored. When we’re able to produce the CO₂ at a higher pressure, it can actually significantly reduce the costs for compressing it before it is transported and stored, typically in the range of 30% to 40%, both in terms of the initial capex of that compression and in the annual operating expenses.

VA: You mentioned solvents, absorbents and fractionation technology. Is there any one technology that Honeywell is seeing more demand for, or is it all of the above?

JG: Two are really standing out. In the pre-combustion space, particularly when in large scale hydrogen production, we’re getting a lot of positive feedback on our CO₂ fractionation technology because of the low cost of capture it enables, the possibility to integrate within the hydrogen production process to drive to very low carbon intensities, and to produce the CO₂ directly as a liquid product. On the post-combustion side, the proven technology in the market is solvent based. So, we’re seeing many customers who are focused on evaluating solvents today to treat their post combustion flue gases.

VA: What specific technologies do you plan to use for Exxon's blue hydrogen project?

JG: We are providing the hydrogen purification equipment called a Honeywell UOP polybed PSA unit. We’re providing the dehydration unit, which is a Honeywell UOP Molsiv unit, a CO₂ fractionation unit, and a hydrogen membrane unit. Essentially how that process works is there is hydrogen-rich syngas that’s produced by the auto thermal reforming unit. Our hydrogen PSA unit will process that gas and separate out a high purity hydrogen product stream. It will also then reject the other components in a tail gas stream, including the CO₂, which will be dehydrated and compressed and head to our CO₂ fractionation column, where the CO₂ will be separated and produced as a high purity CO₂ liquid. From the top of that CO₂ fractionation column, we then can send the gas to a PSA and a membrane unit to further recover hydrogen as a product source. The rejected gas from that stream will be recycled back to the ATR so that any unconverted methane or carbon monoxide will continue to recycle in the unit so that it will be converted to CO₂ and captured by our technology. This results in a very low carbon intensity hydrogen product.

So in summary, if you picture our offering as one large box, the gas is going to come in and be separated into three streams: a high purity H2 product; a high purity liquid CO₂ product; and a hydrocarbon free fuel stream, with the remainder being recycled within the system. All of the CO₂ that leaves the system is essentially captured for storage. That’s the unique and exciting aspect of that project. We can drive to such low carbon intensities of hydrogen production, providing an opportunity for hydrogen to become a fuel substitute and a high value commodity.

VA: Are you finding that more companies are focused on sequestering CO₂ instead of utilizing it? What are ways that some of that captured carbon be used?

JG: Most companies that we’re talking to are focused on sequestration, especially in the U.S., because we have a suitable geological environment to enable that. Additionally, in the U.S., there are different incentive levels available. The U.S. offers a tax credit of $85 per tonne for CO₂ that is permanently stored and $60 per ton of use for EOR. Most of our customers are looking to permanently store it in the ground. Most climate models and market models take that assumption that the majority of CO₂ that’s going to be captured is going to be permanently stored because one, that is the surefire way to prevent it from making its way eventually into the atmosphere and two, the amount of CO₂ that we need to abate is just so large that market outlets don’t really exist for it today in the quantities that people are planning to capture.

With that said, CO₂ can be used in the beverage and food preservation markets. We’re also seeing some interest from customers about using CO₂ as a feedstock for fuels. We recently announced our e-fining process technology that can convert CO₂ and green hydrogen into methanol and eventually into sustainable aviation fuel. So, we continue to look into different ways to utilize CO₂ as a fuel as well as different pathways to produce other chemicals needed by our society. But the near-term focus for most of our customers, especially at the quantities required to make a significant impact on their emissions, is to store the CO₂ permanently.