关于在线清焦？ heater decoking options 加热炉除焦选择 steam-air decoking (steam & air burn)? 蒸汽-空气除焦 performed when heater is off-line? 在加热炉离线情况下操作 heater box temperature is reduced/cooled 加热炉炉膛温度进行降温或冷却 mechanical (pigging) 机械清焦（管道猪） performed when heater is off-line 操作时加热炉进行离线操作 heater box temperature is cooled 加热炉炉膛温度冷却 on-line spalling 在线清焦操作 performed while heater is in service 操作时加热炉在线 1 pass is taken out of service while other passes remain on-line 加热炉炉管1路切出，其他在线生产 steam-air decoking methodology? 蒸汽-空气清焦方法 coke is burnt off the heater tubes by firing the furnace in a controlled decoking process by circulating a steam-air mixture at elevated temperatures. 加热炉炉管内部的焦炭在炉管内燃烧，加热炉通过蒸汽-空气混合之后进行升温，加热炉炉 膛温度逐渐升高之后，加热炉炉管内焦炭燃烧 air is used to burn the coke off the tubes. 空气用来烧管壁上面的焦炭 steam is used to keep the burning temperatures low 蒸汽确保加热炉管壁温度不是很高 such that they do not exceed the maximum tolerable temperatures. 确保加热炉炉管不能超过允许温度 typical decoking time 24 to 48 hours per pass depending on amount of coke in tubes. 典型的清焦周期在24-48小时/路炉管 、、、、、、、、、、、、、、、、、、、、 mechanical decoking 物理清焦 methodology (“pigging”) 管道猪（金属钉猪） coke is removed from the heater tube by pumping a metal studded foam or plastic “pig” with water. the metal studded “pig” rotates such that it scrapes the coke off the inside of the heater tube. 用水带泡沫或塑料制造的金属钉猪将加热炉管内的焦炭剥离 different size and abrasiveness “pigs”are used in the decoking process. “pigs” are slightly smaller than the inside diameter of the heater tube. 使用不同尺寸和硬度的管道猪用于清焦过程，金属猪的尺寸略小于加热炉管道内径 usually “pigs” are pumped through heater several times forward and backward until overall differential pressure across the tube (inlet to outlet) is restored to its original “unfouled” condition. ? typical decoking time is 18 to 24 hours per heater depending on setup time. 通常各种型号的管道猪从入口到出口通过加热炉几次直到加热炉炉管出入口压差降低，同时 加热炉炉管达到清洁标准。典型的清焦时间为18-24小时，每台加热炉取决于安装时间。 ////////////////////////// on-line spalling methodology 在线清焦方法 procedure basis was originally developed by the late mr. lloyd langseth and has been further developed by foster wheeler. 在线清焦的方法是基于已故的mr. lloyd langseth先生发明的方法，同时由福斯特惠勒进行 了进一步的发展 coke is removed from the heater tube by varying the steam or condensate flowrate on the fouled tube such that a thermal shock is created that breaks off the coke from the tube. the spalling medium will transfer the coke particles into the heater effluent where it will be collected in the downstream coke drum. one pass is spalled while the other coils of the heater remain in normal hydrocarbon service. 通过不同的蒸汽（压缩流体）流量，在不同温度在热的加热炉管内对焦炭进行剥离，剥离的 焦炭进入到焦炭塔内，同时其他管路生产的生产方案不变。 typical decoking time is 16 to 24 hours per heater pass. 典型的在线清焦周期为16-24小时/路炉管。 几种清焦方法的比较 steam-air decoking 空气清焦方法 advantages: 优势 – removes almost all coke from the inside of the tubes 能够将加热炉炉管内大部分焦清除 – heater firebox does not need to be fully “cooled” 加热炉炉膛及炉管不需要充分降温、冷却 – can be performed by unit operators- no outside vendor needed 只需要装置操作工便能够进行，而不需要特别的技术支持 disadvantages: 缺点 – time & cost (maintenance & unit loss production) 时间和成本，维修及单元损失的成本 – environmental concerns on venting to atmosphere 由于烧焦造成的环境影响问题 – disposal of water/coke mixture 对水、焦炭混合物的处理 – potential tube rupture 存在着潜在的加热炉炉管破裂问题 – not found to be effective on crude slates containing inorganic material (i.e. canadian crudes, some crude flow improvers) 不能处理加热炉炉管内的无机盐类（如加工加拿大原油或油砂添加的原油流动改进剂） mechanical decoking (“pigging”) 物理清焦 advantages: 优势 – all coke is removed from the inside of the tubes 加热炉炉管内所有焦炭全部能够去除 – more environmentally safe than s.a.d. – no venting to atm. 与空气清焦方法相比对环境更加环保没有对大气的污染 – “pigs” do not score inside of tubes 管道猪不会划伤加热炉炉管 – usually performed faster than s.a.d. 通常清焦速度比蒸汽清焦速度快 – clients have reported longer run lengths than s.a.d. 据客户报告，运转周期比空气清焦更快 – requires outside vendor to perform decoking procedure- unit operators can spend more time on turnaround activities 需要操作由商家完成，操作工有更多精力休息 disadvantages: 缺点 – requires heater to be taken fully out of service 加热炉需要充分的冷却降温，加热炉炉管处理干净 – disposition of “dirty” water required 需处理大量脏水要 – downtime is 1 to 3 days/heater 加热炉需要停工1-3天 – cost - specialized decoking vendor needed 浪费-需要专门的水力除焦供应商 ////////////////////////////////////////////// on-line spalling 在线清焦操作 advantages: 优势 – heater remains in service during procedure, one pass at a time 在线清焦时加热炉在正常开车，不须切出，只需选择合适的清焦时刻 – immediate feedback on effectiveness once pass is back in service 对加热炉清焦操作可以及时进行，清焦效果可以及时反馈 – allows extended heater run length before “pigging” is required 在管道猪或蒸汽-空气清焦操作之前延迟焦化加热炉生产的周期 – coke is collected in downstream coke drum 将焦炭全部回收在下游的焦炭塔内 – regular decoking program can be developed by refiner 操作人员能开发完成的清焦程序 disadvantages: 缺点 – may not get all coke off a particular tube section-still need to eventually fully decoke 有可能不能将焦化加热炉炉管内所有的焦炭清除 – potential tube damage due to tube expansion/contraction 加热炉炉管发生扩张、伸缩有可能造成加热炉加热炉炉管损伤 – potential u-bend corrosion/erosion 对加热炉炉管的u型弯头可能造成腐蚀及侵害 – potential coke blockage of tube – “pigging” required 有可能发生焦炭堵塞加热炉炉管 – can only be performed on 3 or 4 pass heaters with individual pass firing 单路在线清焦操作可能需要3-4个司炉工进行操作查看更多
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