Syngas production for gas-to-liquids applications: technologies, issues and outlook
Syngas production for gas-to-liquids applications: technologies, issues and outlook
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DOI：
10.1016/s0378-3820(01)00140-0
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发表时间：
2001-06
影响因子：
7.5
通讯作者：
D. J. Wilhelm;D. Simbeck;A. Karp;R. Dickenson
中科院分区：
文献类型：
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作者：
D. J. Wilhelm;D. Simbeck;A. Karp;R. Dickenson
目前气制油（GTL）的主要兴趣在于烃的费托（F-T）合成。虽然GTL的合成气（合成气）可以从任何碳基原料（碳氢化合物，煤，石油焦，生物质）生产，但迄今为止成本最低的合成气路线是基于天然气。因此，GTL的重点主要是伴生气，即所谓的搁浅或偏远天然气储量，以及目前尚未经济开发的较大天然气储量。从天然气生产合成气的主要技术有：催化甲烷蒸汽重整（SMR）、两步重整、自热重整（ATR）、部分氧化（POX）和热交换重整。本文讨论了这些技术的特点及其商业用途。还简要讨论了正在进行的研发工作，以开发低成本的合成气发电技术。还讨论了GTL大规模合成气生产的相关商业经验。作为参考，就合成气流速而言，一个20，000 B/天的F-T装置相当于三个2500 mt/天的甲醇装置。单列甲醇工厂现在的产量超过2500吨/天，并且已经宣布接近3000吨/天。各种合成气生产技术的预计相对规模经济表明，两步重整和最终ATR应该是大规模GTL工厂的首选技术。然而，对于一个20，000 B/天的F-T液体工厂，资本费用仍然是制造成本的主要部分。合成气生产（制氧装置和重整）占这种规模GTL装置总资本成本的一半。虽然空气吹制重整消除了昂贵的氧气设备，但空气吹制重整不太可能与氧气吹制重整竞争或提供氧气吹制重整的灵活性。对得出这一结论的原因进行了讨论。由于FT催化剂和反应器设计的改进，建议的和未来的GTL设施的成本应大大低于其非常昂贵的制造商，其中最重要的是由沙索公司率先。在没有突破性技术的情况下，规模经济将是GTL实现更大经济可行性的唯一重要机制。然而，即使进一步降低成本，在原油价格水平大幅上涨之前，GTL工厂的经济可行性仍将限于特殊情况。从长远来看，如果能够开发出一种陶瓷膜反应器（结合空气分离和部分氧化），使GTL的投资成本降低20%，这是研发工作的目标，GTL在原油价格低于20美元/B的情况下可能在经济上可行。
The main gas-to-liquids (GTL) interest now is in Fischer–Tropsch (F–T) synthesis of hydrocarbons. While synthesis gas (syngas) for GTL can be produced from any carbon-based feedstock (hydrocarbons, coal, petroleum coke, biomass), the lowest cost routes to syngas so far are based on natural gas. Thus, the focus for GTL has been largely on associated gas, so-called stranded or remotely located gas reserves, and larger gas reserves that are not currently being economically exploited. The principal technologies for producing syngas from natural gas are: catalytic steam methane reforming (SMR), two-step reforming, autothermal reforming (ATR), partial oxidation (POX), and heat exchange reforming. The distinguishing characteristics of these technologies and their commercial uses are discussed in this paper. Ongoing R&D efforts to develop lower-cost syngas generation technologies are also briefly discussed. Relevant commercial experience with large-scale syngas generation for GTL is also discussed. As a frame of reference, in terms of syngas flow rates, a 20,000 b/day F–T plant would be comparable to three 2500 mt/day methanol plants. Single-train methanol plants are now producing more than 2500 t/day—and plants approaching 3000 mt/day have been announced. The projected relative economies of scale of the various syngas production technologies indicate that two-step reforming and ultimately, ATR, should be the technologies of choice for large-scale GTL plants. Nevertheless, for a 20,000 b/day F–T liquids plant, capital charges still dominate the manufacturing costs. Syngas production (oxygen plant and reforming) comprises half of the total capital cost of this size GTL plant. While air-blown reforming eliminates the expensive oxygen plant, air-blown reforming is unlikely to be competitive with, or offer the flexibility of, oxygen-blown reforming. The reasons for this conclusion are discussed. The proposed and future GTL facilities should be substantially less costly than their very expensive predecessors—as the result of improvements in FT catalyst and reactor design, the most significant of which have been pioneered by Sasol. In the absence of a breakthrough technology, economy of scale will be the only significant mechanism by which GTL can achieve greater economic viability. However, even with such further cost reductions, the economic viability of GTL plants will remain confined to special situations until crude price levels rise substantially. In the long term, if a ceramic membrane reactor (combining air separation and partial oxidation) can be developed that enables the 20% reduction in GTL investment costs that the R&D effort is targeting, GTL could become economically viable at crude prices below US$20/b.