In August 2017, a silo fire occured at the Pacific BioEnergy (PacBio) 350,000-metric-ton-per-year pellet plant in Prince George, British Columbia. The tactics used to combat the fire resulted in a successful outcome, but this is in contrast to a long history of silo and dome fires resulting in the complete loss of the structures, major damage to surrounding infrastructure, and injury and loss of life.
2017年8月，在不列颠哥伦比亚省乔治王子的太平洋生物能源(PacBio) 年产35万吨颗粒的工厂发生了一场筒型料仓火灾。此次用来扑灭火灾的方法与以往长期以来筒型料仓与穹顶料仓火灾造成建筑物与基础设施严重破坏及人员伤亡对比，获得了成功。
Smoke from smoldering wood pellets inside a PacBio silo containing 3,500 metric tons was first noticed on the evening of Aug. 23. Over seven days, the fire was controlled, extinguished, the silo was saved, and there were no injury or loss of life. Pellets worth over $500,000 were damaged, but millions of dollars of pellet plant infrastructure was not. Unfortunately, although the silo did not collapse and there were no explosions or fires that damaged the pellet mill or caused injury, the silo will be demolished because of uncertainty regarding its structural integrity.
8月23日晚，人们首次注意到在一个装有3500吨的PacBio筒仓内浓烟弥漫。在7天的时间里，火势被控制，熄灭，没有受伤或人员伤亡。价值超过50万美元的颗粒遭到破坏，但数百万美元的颗粒工厂基础设施却没有受损。不幸的是，尽管筒仓没有倒塌也没有发生爆炸或火灾，但由于火灾引发其结构完整性的不确定性，将被拆除。
Credit for this successful outcome belongs to the Pacific BioEnergy management and operations team, and the first responders from the Prince George fire department, all of whom followed a carefully crafted plan for controlling and extinguishing the fire. PacBio CEO Don Steele, and Vice President of Operations Shawn Bells and his operations team, along with vital guidance and support from the author of this paper, John Swaan, applied industry best practices to their tactical planning. They thought carefully before they acted, and used information developed from years of experience. They proceeded carefully, but deliberately, with a primary objective of keeping everybody safe.
这一成功归功于太平洋生物能源管理和运营团队，以及乔治普林斯消防部门的第一反应人员，他们都遵循了一项精心制定的控制和灭火计划。太平洋生物能源首席执行官唐·斯蒂尔和运营团队的副总裁肖恩·贝尔和他的运营团队，以及本文作者约翰·斯瓦恩(John Swaan)的重要指导和支持，将行业最佳实践应用于他们的战术规划。他们在行动之前仔细考虑，并利用多年积累的经验信息。他们小心翼翼地谨慎进行，确保证每个人的安全。
What Not to Do 什么不能做
Historically, the industry has examples of not-so-successful outcomes of silo or dome fires. This has been due to the lack of knowledge about the characteristics of wood pellets, often by both pellet plant operators and first responders, and incorrect and self-defeating tactics. The following incorrect tactics have been the cause of loss of buildings and other assets, pellets, injuries and worst of all, in several incidents, loss of life.
从历史上看，该行业有一些不太成功的筒仓或穹顶仓火灾的例子。这是由于缺乏对木颗粒的特性的认识，通常是由颗粒厂的操作员和第一反应者不正确的和自我挫败的战术。以下不正确的策略是造成建筑物和其他财产损失的原因，如颗粒、人员受伤，在几次最坏事件中还造成人员亡故。
Although water may help with controlling the flames of an out-of-control silo fire incident, deluging or spraying water on top of the pellets in a silo, dome, or flat storage will never aide in extinguishing a smoldering mass of wood pellets. The wood pellets on the top of the pile will absorb the water and swell, creating a blanket of material, restricting the ability of water to penetrate anywhere near the core of the smoldering pellets located somewhere within the center of the pile of pellets. Water contacting hot, pyrolyzed wood pellets will generate carbon monoxide (CO) and hydrogen, which add to the seriousness of the conflagration, and is not helpful for extinguishing a silo fire. Water may also create pinnacles and/or columns within the silo, which may become a problem when trying to remove the product.
尽管水可以帮助控制失控的筒仓火灾的火焰，但在一个筒仓、穹顶或平仓中，在颗粒顶部冲水或喷洒水，将永远不会帮助熄灭一团燃烧的颗粒。顶部的颗粒将吸水膨胀，形成一层限制水渗透到任何位于积堆闷烧颗粒中心附近的物质。水接触热的，热解的颗粒会产生一氧化碳和氢气，这增加了火灾的严重性，并无助于灭火。水也可以在筒仓内产生尖峰和/或列柱，当试图移除产品时，这可能成为一个问题。
To immediately begin removing the wood pellets from the silo, dome or flat storage pile before the pyrolysis activity within the core of the pile has been extinguished, is a recipe for disaster. The gases being released by the pyrolysis activity are nasty and dangerous, especially the methane, CO and other life-threatening gases. The ignition point of methane released from wood pellets is very low, and will ignite when it encounters the smoldering core, and the supply of oxygen from the open air. In other words, when removing the pellets down to the level where the pellets are exposed to both the smoldering core and atmospheric air, chances of an explosion and/or a rapidly spreading fire are very high.
在积堆闷烧颗粒的热解活动被扑灭之前，立即开始从筒仓、穹顶或平板储存堆中取出颗粒，这是一种灾难的起因。热解活动释放出的气体是危险的，特别是甲烷、一氧化碳和其他威胁生命的气体。从颗粒中释放出的甲烷的燃点非常低，当它遇到闷烧的中心与空气中的氧气时就会燃烧起来。换句话说，当把颗粒移出到闷烧中心与大气接触时，发生爆炸和/或火焰迅速蔓延的可能性非常高。
Best Practices最佳实践
The first lesson learned is the importance of having a plan based on best practices, and training the local fire department. This kind of incident has the potential for major injury and loss of life. Money can replace material assets, but not life. Safety of all personnel on-site and the surrounding area is priority one. In the PacBio fire, each deliberate step taken to mitigate the incident by the PacBio team and all support resources was focused on safety first.
第一个教训是，制定一个基于最佳实践的计划和培训当地消防部门的重要性。这类事件有可能造成重大伤害和生命损失。金钱可以代替物质资产，但不能代替生命。现场所有人员及周围区域的安全是优先考虑的。在太平洋生物能源火灾中，为减轻太平洋生物能源团队和所有支持资源的事故所采取的每一步行动都聚焦在安全第一。
The PacBio operations team also maintained control of all actions taken, including those by the first responders. The typical reaction by a fire department is to deluge a fire with water. By having actions controlled by the PacBio team, that “what not to do” action was avoided. The Prince George fire department had trained at the site, and understood that a silo fire is not a typical incident. The response required direct communications with the fire department but with control by the pellet plant operations team.
太平洋生物能源团队还保持对所有采取的行动的控制，包括第一批反应者所采取的行动。消防队的典型反应是用水把火扑灭。通过由太平洋生物能源团队控制的行动，避免了“什么不能做”的行动。乔治普林斯消防队在现场进行了训练，他明白颗粒筒仓火灾不是典型事故。响应要求与消防部门直接沟通，但由颗粒工厂运营团队控制。
Taking time to research information resources, craft a plan, and work with the local fire fighters is the major reason that the PacBio incident has a successful conclusion. Drawing on the experiences of other incidents successful or not, helped in the decision making of steps taken.
花时间研究资源信息，制定计划，和当地的消防队员一起工作是太平洋生物能源事件成功的主要原因。借鉴其他成功或不成功的经验，帮助决策制定步骤。
The second lesson learned is that inert gas injection significantly lowers the probability of negative outcomes. The danger of a gas and/or dust explosion causing serious injury, and extensive property damage is very possible. Nitrogen is most effective for minimizing these risks, and provides a low-risk pathway to gain control of the smoldering pyrolysis inside the pile while emptying the material.
第二个教训是，惰性气体喷射显著降低了负面结果的可能性。气体和/或粉尘爆炸的危险会造成严重的伤害，并可能造成重大的财产损失。氮是最有效地降低这些风险，并提供一个低风险的途径，以获得控制积堆闷烧颗粒的热解，同时清空材料。
Nitrogen injection is recognized as the better solution as an inert gas for mitigating silo fire incidents—it is more readily available in large quantities, is easier to vaporize, and is more economical than CO2. The use of nitrogen gas was a key part of the tactics used to control and extinguish the PacBio fire.
氮的注入被认为是一种更好的解决方案，因为它是一种惰性气体，可以用来减轻颗粒筒仓火灾——它更容易被大量地使用，更容易汽化，而且比二氧化碳更经济。使用氮气作为控制和扑灭太平洋生物能源火灾是策略的关键部分。
We recommend a review of the report published in 2013 by Henry Persson of SP Technical Research Institute of Sweden titled, “Silo Fires–Fire Extinguishing and Prevention, and Preparatory Measures.” This report should be a standard reference for every pellet plant, and for every fire department that may respond to a pellet silo or dome fire.
我们建议对2013年瑞典SP技术研究所的亨利·珀森(Henry Persson)发表的报告进行评论，标题为“筒仓灭火和预防，以及准备措施”。这份报告应该是每一个颗粒厂，可能会对颗粒筒仓或圆顶火灾作出反应的消防队的标准参考。
At PacBio, the report’s recommended nitrogen injection flow rates were referenced, and calculations for the size of the silo were made, and very quickly a call to the local gas supplier Praxair was made. A mobile nitrogen vaporizer and tank unit, along other with tankers to follow, were mobilized from Edmonton, Alberta. The gas and oil industry utilize this type equipment regularly. An engineer from Solid Industrial Solutions was also dispatched to provide on-site assistance with the setup of the nitrogen distribution system, and control the nitrogen injection of the flow rate.
在太平洋生物能源，报告推荐的氮注射流率被引用，并计算了筒仓的大小，并很快地给当地的天然气供应商Praxair打了电话。从艾伯塔省的埃德蒙顿调集了一个移动氮气汽化器和罐装置，以及其他槽车。天然气和石油工业经常使用这种类型的设备。此外，还派遣了一名来自固体工业解决方案的工程师，为氮分配系统的建立提供现场协助，并控制氮注入流量。
Based on the needed flows and volumes of nitrogen, the PacBio team specified how to fabricate the lances to be driven into the side of the 80-foot (~24 meter) diameter silo. Within 24 hours of the call to mobilize the nitrogen; the vaporizing unit was set on-site, injection lances were in place, nitrogen distribution system connected, and the nitrogen injection began to flow.
根据需要的流量和氮量，太平洋生物能源团队明确了如何将这些长枪组装连接到80英尺(约24米)直径筒仓的一侧。在24小时内调集了氮气，现场设置了汽化装置，喷枪到位，氮分配系统连接，氮气注入开始流动。
Several attempts were made to foam the top of the silo, but regardless of the foam densities, the deluge system originally installed for water was not adequate for dispersing foam evenly over the top of the pellets to create an effective proper seal.
几次尝试为了在筒仓顶部发泡，但不管泡沫密度如何，原设计的喷水系统不足以将泡沫均匀地分散在颗粒的顶部，从而形成有效的密封。
Emptying the silo commenced within 48 hours of nitrogen injection, after the oxygen level measures within the head space of the silo dropped below 10 percent. The PacBio team safely handled and evacuated the removed material. The first responders, equipped with respiration equipment, kept all personnel safe and out of harm’s way. Wood pellets and the carbonized clumps coming from the silo were conveyed safely, without incident, to a flat area away from the plant. Even when meeting atmospheric air, there were no issues.
在氮气注入后48小时内，将筒仓开始清空，在仓头空间内的氧气含量降低到10%以下。太平洋生物团队安全地处理并疏散了被移除的材料。第一批急救人员配备了呼吸设备，所有人员都安全且不受伤害。木质颗粒和从筒仓中产生的碳化团块安全地送到远离工厂的平坦区域。即使在大气中，也没有问题。
It took approximately seven days to evacuate the 3,500 tons of aborted material, and each truckload was safely moved to a secure area away from other fiber residue stockpiles, and deluged with water as they were dumped, to ensure there were no residual hot spots.
大约花了7天的时间才撤离了3500吨的废弃材料，每一辆卡车都安全的转移到远离其他纤维残留储存的安全区域，并在被倾倒的时候用水淹没，以确保没有残留的火星。
The third lesson is to be prepared to detect and control silo/dome fires. Monitoring, detection and suppression systems must be installed and maintained in good working order. A properly installed and operating heat monitoring system will assist with discovering the location of a developing hot spot within the pellet silo or dome. Early warnings of an incident will be detected and alarmed when temperature monitors inside the silo are operating correctly. Early warning, before smoke is observed, will significantly lower the loss of product, and the likelihood of a much more serious incident.
第三个教训是准备探测和控制筒/圆顶仓火灾。监测、检测和抑制系统必须安装并保持在良好的工作状态。正确安装和运行热监测系统将有助于发现在颗粒筒仓或圆顶内发展热点的位置。当筒仓内运行正常的温度监测器，将会检测到事故的早期预警并发出警报。在出现到烟雾之前，早期预警将大大降低产品的损失，以及发生更严重事件的可能性。
Carbon monoxide and oxygen monitors installed on the top of the silo, providing constant measurement, will also assist with early incident detection. Once the nitrogen was being injected into the PacBio silo, obtaining readings without sampling equipment already installed at the top of the silo made it more challenging to determine the gas levels required for removing the material from the silo material safely. Testing and maintaining these systems must be part the weekly PM (preventive maintenance) program.
安装在筒仓顶部的一氧化碳和氧监测仪，提供连续的测量，也将有助于早期的事件检测。一旦氮被注入到颗粒筒仓中，即可获得的读数，没有安装在筒仓顶部的取样设备，会使得确定从筒仓材料中安全地取出材料所需的气体水平更具挑战性。测试和维护这些系统必须是每周PM（预防性维护）计划的一部分。
A permanent, properly sized and installed nitrogen injection system within the silo or dome, complete with a manifold in a safe location with a convenient hookup, is critical. If there are no nearby suppliers of nitrogen and evaporators, the plant should strongly consider having that equipment on-site. The quickly rigged manifold used at the PacBio plant was not optimal for controlling flow to the lances. Managing an even flow rate properly distributed into the silo would have been more effective, and may have controlled the pyrolyzing core quicker.
一个永久性的、适当大小的、安装在筒仓或穹顶内的氮气喷射系统，在一个安全的地方配有一个方便的连接装置，是至关重要的。如果附近没有氮气和蒸发器供应商，工厂应该考虑在现场安装这种设备。在太平洋生物能源工厂配备快速可操纵的到喷枪的氮流量可控的汇流排是必须的。操作一个均匀分配到筒仓的流量会更加有效，并且可能会更快地控制热裂解中心。
Silo or dome ventilation systems control are critical when managing a silo fire incident. The system should have the ability to shut down and seal off bottom asperation fans, as well as the ability to control the top ventilation of the silo. This is very beneficial to minimize the exhausting gas flow and improve nitrogen penetration, and to reduce the total volume of nitrogen required.
筒仓或穹顶通风系统控制在管理筒仓火灾时至关重要。该系统应具有关闭和封闭底部吹气风扇的能力，以及控制筒仓顶部通风的能力。这对减少废气的排放和提高氮的渗透率是非常有益的，并能减少所需的总氮量。
Installing a proper permanent deluge system that can accommodate both water and distribute foam properly over the top of the entire pile of pellets would be very effective. Not having the ability to seal off the material at the top of the silo or dome allows the injected nitrogen to escape more readily, which lowers the ability to control and stop the pyrolysis. The PacBio incident may have been controlled with less nitrogen, and more quickly if a foam cap had been applied.
安装一个适当的永久性喷淋灭火系统，既能适应用水，又能适当地将泡沫均匀地分布在整个颗粒的顶部，这将是非常有效的。没有能力将材料在筒仓或穹顶顶部密封，注入的氮气更容易逃逸，这降低了控制和阻止热解的能力。如果使用泡覆盖,则太平洋生物能源事件可能会用较少的氮气,且会更快得到控制。
Key Causes主要成因
In most cases, it’s suspected that the ignition that sets off the pyrolysis activity is due to some foreign hot debris. This could be from failed pellet mill roller bearings, conveyor system roller and/or belt failure, or molten steel from hot maintenance work. All of the above have been the causes of incidents.
在大多数情况下，人们怀疑点燃热裂解活动的是由于一些外部的火源。这可能来自于损坏的颗粒压辊轴承，输送系统辊和/或皮带故障，或热工维修作业带来的热钢水((译者补充:如切割/焊接焊渣)。以上这些都是造成事故的原因。
Because wood pellets are a biogenic product, self-heating can also be the cause of silo fire incidents. This may be due to microbiological activity, chemical oxidation processes, moisture migration, moisture absorption, or a combination of these. This process usually occurs within a temperature range up to 45 to 75 degrees Celsius, since microbes die at higher temperatures. Microbial activity primarily generates CO2, and may be detected by measuring the CO2 concentration in the silo headspace. At higher temperatures, self-heating is derived from chemical oxidation processes. In wood pellets, the cause is usually a chemical oxidation process, since the pellets are more or less sterilized during the production process. Practical experience shows that this oxidation process is especially likely in newly produced pellets, in part due to the oxidation of different resins contained in the wood material.
由于木颗粒是一种生物成型的产物，自热也可能是筒仓火灾发生的原因。这可能是由于微生物活动，化学氧化过程，水分迁移，吸湿，或这些的组合。这个过程通常发生在温度范围在45到75摄氏度之间，因为微生物在高温下死亡。微生物活动主要产生二氧化碳，通过测量仓顶空间的CO2浓度可以检测到。在较高的温度下，自热是由化学氧化过程产生的。在颗粒中，其原因通常是化学氧化过程，因为在生产过程中，颗粒或多或少会被灭菌。实际经验表明，这种氧化过程尤其可能发生在新产生的颗粒中，部分原因是由于木材材料中含有不同的树脂。
Call to Action动行号召
Every wood pellet industry stakeholder across the globe, from producers to end users, must share the learnings of this incident, and adopt the protocols and technology for mitigating, and hopefully, eradicating, silo fire incidents.
从生产者到最终用户，全球的每一个木材颗粒行业的利益相关者都必须分享这一事件的教训，并通过方案和技术来减轻，并希望能够根除颗粒料仓火灾事故。
This call to action includes all wood pellet industry associations and institutions, wood pellet plants, shipping terminals and power plant owners. It is essential for both safety and reliability that these best practices be understood and adopted by wood pellet plant operations management and personnel, local and regional first responders and fire brigades, first responder training academies, governmental work place safety institutions, fire protection equipment providers, wood pellet handling providers (silos, domes, conveyors), rail and shipping companies, and wood pellet project developers, engineers and EPC contractors.
这一行动号召包括所有的颗粒行业协会和机构，颗粒厂，船舶码头和生物发电厂业主。对安全性和可靠性至关重要,这些最佳实践是理解和采用木屑工厂运营管理和人员,地方和区域应急部门人员和消防队,急救员培训学院、政府工作场所安全机构、消防设备供应商,木颗粒处理供应商(筒仓、穹顶、输送机)、铁路和航运公司,和木头颗粒项目开发人员、工程师和EPC承包商。
Any entity in the supply chain that has pellet storage in silos or domes must be encouraged to assess their current wood pellet storage systems for their ability to detect and control fire incidents and, if deficient, install protection technology and equipment, including ventilation controls, foaming equipment and nitrogen injection. Wood pellet plants, and wood pellet storage and shipping terminals, should identify and develop a relationship with a nitrogen supply and gas engineering service nearest to their respective plant location. A 10- to 12- hour transport radius would offer a sufficient response time. Any farther away, an on-site nitrogen generation system should be considered.
必须鼓励供应链中有颗粒储存的任何实体，以评估其现有的木质颗粒储存系统，以检测和控制火灾事故，如果有缺陷，应安装保护技术和设备，包括通风控制、发泡和氮气注射设备。木质颗粒厂，木颗粒储存和运输终端，应识别并发展与附近的工厂所在地附近的氮供应和气体工程服务的关系。10到12小时的传输半径将提供足够的响应时间。在更远的地方，应该考虑一个现场的氮生成系统。
Any entity in the supply chain that has pellet storage in silos or domes must be encouraged to develop a fire incident mitigation and training plan. They must ensure that all operations personnel and firefighters who will be called to the site understand the characteristics of wood pellets within a silo or dome, and how to fight the fire with maximum effectiveness, and minimum danger and damage. All personnel should be acquainted with the dangers of the gasses contained within the smoke being released.
必须鼓励供应链中有颗粒储存在筒仓或穹顶内的任何实体，以制定火灾事故缓解和培训计划。他们必须确保所有的操作人员和消防人员都能了解到在一个筒仓或穹顶内的木质颗粒的特性，以及如何以最大的效率和最小的危险和伤害来对抗火灾。所有人员都应了解所排放的烟雾中所含气体的危险性。
The statement, “It is not if there is a fire, but when” should never be allowed to influence stakeholders into a state of complacency. Every stakeholder within the wood pellet industry must strive to ensure that the “if” does not instill a sense of acceptance with business-as-usual, and that the chances of “when” are close to zero.
声明中说，“如果没有火灾，就不会有火灾，但当” 不应该被允许影响利益相关者陷入自满状态。木质颗粒行业的每一个利益相关者都必须努力确保“如果”不像以往一样对业务灌输一往常态的认可，并将“何时”的机会接近于零。
However, should there be a “when,” all stakeholders must be fully informed on how to deal with an incident, and fully prepared to deal with it safely and effectively.
然而，如果有“什么时候”，所有的利益相关者必须充分了解如何处理一个事件，并充分准备好安全有效地处理它。
-By John Swaan | March 17, 2018 深圳东启节能科技有限公司 翻译 2018-3-25
