据安迅思休斯敦1月2日消息，近期原油成本的下降和新建裂解装置陆续投产将增加2019年美国的丙烯产量，尽管出口和非计划停工可能会令市场出现一些波动。

2018年大部分时间，美国丙烯供应紧张，导致价格上涨。2018年初，由于一些丙烷脱氢(PDH)装置非计划停工，美国国内丙烯价格大幅上涨。2018年下半年的大部分时间里，由于一些PDH装置发生故障和裂解装置丙烯产量有限，美国国内丙烯价格上涨。

虽然2019年美国PDH装置的生产可能继续不稳定，但2018年底来自于裂解装置的丙烯产量出现回升，这一趋势很可能持续到2019年。

在2018年的大部分时间里，裂解装置的丙烯产量减少，主要由于裂解装置中乙烷原料的使用增加，丙烯副产品的产量受到限制。 

随着美国新建裂解装置在2018年3月和7月投产，美国国内乙烯供应大幅增加，并导致乙烯价格大幅下跌。

低乙烯价格挤压了美国裂解装置的利润率，促使裂解装置使用更多的乙烷，因为乙烷是乙烯生产最经济的原料。2018年大部分时间，强劲的原油价格支撑了石脑油、丙烷和丁烷等较重原料的价格，这往往使裂解较重的原料变得不经济。

2018年年中，乙烷在美国裂解装置原料中所占的比例从前一年的60%上升到75%以上。

2018年末，原油价格下跌和裂解装置利润率上升，改善了重质裂解原料的经济性。预计2019年原油价格不会大幅上涨，这可能会保持重质裂解原料的经济可行性。

由于美国燃料出口(尤其是对墨西哥出口)的强劲需求，2019年美国炼油厂仍将保持较高的开工率水平，因此预计来自于炼油厂的丙烯产量仍将保持强劲。

庞晓华 摘译自 ICIS

原文如下：

US propylene production to be bolstered by new crackers, low crude oil.

Recent reductions in crude oil costs and new cracker start-ups are set to increase propylene production in 2019, although exports and outages could keep some volatility in the market. 

Propylene supply was tight during much of 2018, which led to some pricing upswings. Early in the year, prices spiked amid several outages for propane dehydrogenation (PDH) units. Through much of the second half of 2018, prices were elevated amid some PDH issues and limited propylene production from crackers. 

While production from PDH units may continue to be volatile in 2019, propylene production from crackers improved in late 2018 and that trend is likely to continue into 2019. 

Propylene production from crackers had been limited during much of 2018 due to the increased usage of ethane feedstocks, which produce the least amount of co-products like propylene. 

As new crackers came on line in March and July, ethylene supply lengthened and ethylene prices plummeted. 

The low ethylene prices narrowed cracker margins, prompting crackers to utilise more ethane as it is the most economical feedstock for ethylene production. Strong crude oil values during much of 2018 had supported prices for heavier feedstocks like naphtha, propane and butane, which often made the heavier feedstocks uneconomical. 

The share of ethane in the US feedslate rose above 75% by mid-2018, up from the 60s% in the prior year. 

Late in 2018, a decline in crude oil values and increased cracker margins had improved economics for heavier cracker feedstocks. Crude oil values are not expected to rise significantly in 2019, which may keep economics for heavier feedstocks workable.