Hydrocarbon leakage and inadequate process safety management led to an explosion at this California refinery, CSB says.

CSB稱，油氣泄漏和工藝安全管理的不足導致了加利福尼亞煉油廠的爆炸。

Credit: CSB

美國化學安全委員會稱風險管理的漏洞導致了爆炸

美國化學安全委員會（CSB）在報告中提到，基本工藝安全管理的錯誤（所有美國煉油廠的一些共同現象）導致了位于加利福利亞托倫斯的埃克森美孚煉油廠2015年事故的發生。

CSB主席Vanessa Allen Sutherland說，埃克森美孚煉油廠缺乏恰當的風險管理制度，這意味著“工人們基本上是盲目地在運行每個工藝單元。”

事故造成四名工人受傷，無人重傷。爆炸造成碎片橫飛，一些盛裝氫氟酸（HF）的桶從天而降。許多煉油廠在烷基化的工藝中都在使用劇毒的氫氟酸。

爆炸發生在靜電除塵器上，這是煉油廠空氣污染控制系統的一部分。CSB確認，未被檢測到的碳氫化合物通過流體催化裂解裝置的管道發生回流，并在除塵器中被點燃。報告稱，在事故發生時，埃克森美孚煉油廠已經關閉該裂解裝置，計劃對其進行維修，但是埃克森美孚煉油廠并沒有將其與其他設備有效隔離。

CSB說，埃克森美孚煉油廠缺乏可以標志油氣泄漏的碳氫化合物檢測設備。CSB補充道，這種檢測設備的缺乏是一個全行業問題。

事故關停了煉油廠，削減了一年多的產量。事故還加劇了附近約15萬居民的擔憂。

在美國，約150家煉油廠中的近三分之一都在使用氫氟酸。即使在極低濃度下，它也會造成人員傷害或致命。

CSB還在調查如果碎片擊中了盛氫氟酸的桶會造成的潛在影響。然而，埃克森美孚公司最近卻將煉油廠出售給了BPF控股公司，并隱瞞了CSB需要的信息，稱這種調查超出了委員會的權限。

埃克森美孚告訴C&EN，沒有證據表明此次事件會給社會帶來任何風險。此起事故和2015年以來的其他四次事故之后，加利福利亞地區的監管機構已經展開了一項關于在煉油廠更換氫氟酸的研究。他們的目標是在年底前公布其研究結果。

（本文經《化學與工程新聞》（美國化學學會）許可轉載。文章于2017年5月8日首次發表。）

U.S. Chemical Safety Board says gaps in risk management led to blast

Fundamental process safety management errors—some common to all U.S. refineries—led to a 2015 accident at an ExxonMobil refinery in Torrance, Calif., says a May 3 report from the U.S. Chemical Safety Board.

ExxonMobil’s lack of proper protocol to manage risk meant “workers were essentially running the unit blind,” says CSB Chairwoman Vanessa Allen Sutherland.

The accident injured four workers, none seriously. The explosion sent debris flying, with some landing near tanks of hydrofluoric acid (HF). Many refineries use this highly toxic chemical in the alkylation process.

The explosion occurred in the electrostatic precipitator, part of the refinery’s air pollution control system. Undetected hydrocarbons back-flowed through piping from the fluid catalytic cracking unit and ignited in the precipitator, CSB determined. At the time of the incident, the cracking unit was shut down for planned maintenance but was not sufficiently isolated from the rest of the facility, the report says.

The refinery lacked hydrocarbon detection equipment that might have flagged the leak, CSB says. The absence of such equipment is an industry-wide problem, it adds.

The accident shut down the refinery and cut output for more than a year. It also heightened fears of some 150,000 nearby residents.

HF is used in about one-third of the some 150 refineries in the U.S. It can seriously injure or kill even in small concentrations.

CSB is also investigating the potential impact if debris had hit the HF storage tanks. However, ExxonMobil, which recently sold the refinery to PBF Energy, has withheld the information CSB asked for, saying this aspect of the probe exceeds board’s authority.

The company tells C&EN there is no evidence the incident posed any risk to the community.

Following this incident and four others since the 2015 accident, regional regulators in California have launched a study to consider substitutes for HF at refineries. They are aiming to release their findings by year’s end.

This article is reproduced with permission from Chemical & Engineering News (© American Chemical Society).

The article was first published on May 8, 2017.