Coker unit

Feeds and products from a delayed coker unit (using different feeds) ... 

Incorrect metallurgical valve leaked coke resulting in an explosion under the coker unit. 

Fluid catalytic cracking (FCC) and coker units generate most of the cyanides in refineries... 

Figure 18 Cyanide generation and disposal in a typical refinery. Cyanide and other gases are formed in FCC or coker units during cracking of organics and go overhead on the fractionating column. Wash water dissolves these gases and becomes sour water. Part of the cyanide is removed by the sour water stripper and the rest goes to the sewer and eventually to the wastewater treatment system. (From Ref. 48.)...

A major fire that resulted in 65 million in property damages occurred early in the morning (4 21 A.M.) on August 2, 1993. The central unit of three delayed coker units was the origin of the fire. Each of the three units consisted of four 100-ft. metal coke drums mounted about 40 ft. above grade. The sustained, intense fire caused other pipes in the area to rupture, releasing more hydrocarbons. Over 95 fire brigade members battled the fierce fire for nearly three hours. [21] The fire killed three people. 

A typical delayed coker unit consists of coking, fractionation and blowdown sections, along with coke handling facilities. Coker gas is either processed in a dedicated vapor recovery unit or may be sent for processing, together with other gases, to a centralized vapor recovery unit. 

The process is designed to utilize olefinic feedstocks from steam crackers, refinery FCC and coker units, and MTO units, with typical C4 to C8 olefin and paraffin compositions. The catalyst exhibits little sensitivity to common impurities such as dienes, oxygenates, sulfur compounds and nitrogen compounds. 

The process specifications on raw material speed through furnaces coils imposed the use of two or four parallel passes, e.g. the fumaees from the atmospherie distillation unit, vacuum distillation unit, catalytic reforming unit, coker unit, catalytic cracking unit. The conventional control structure of radiant section for a typical tubular furnace from the atmospheric distillation unit (output capacity 3.5 Mt/year) is presented in figure 1 [1]. Because the conventional temperature control system only controls one outlet temperature or in the best case the temperature of the mixing point, in current operations there are several situations [1, 2, 3] ... 

Economics ROG streams from FCC units, deep catalytic cracking (DCC) units, catalytic pyrolysis process (CPP) units and coker units are normally used as fuel gas in refineries. However, these streams contain significant amounts of olefins (ethylene and propylene), which can be economically recovered. In fact, many such streams can be recovered with project payout times of less than one year. 

According to the chemical safety alert Hazards of Delayed Coker Unit (DCU) Operations (US EPA, 2003), some actions have been reported as beneficial to diminish the occurrence of incidents associated with incorrect valve activation due to mistaken coke drum or module identification. Some of the actions Usted in the referred safety alert are provide interlocks for valves that are manually operated as part of the switching/decoking cycle to avoid unanticipated valve movement provide interlocks for automated or remotely activated valve switching systems . These recommended actions can be achieved with the definition of set of permissive logics to prevent inadvertent valve operations. This set of logics can serve as an automated decision support system for the coke drum cycle. 

United States Environmental Protection Agency. 2003. Hazards of Delayed Coker Unit (DCU) Operations, Chemical Emergency Preparedness Office (5104-A), EPA-550-F-03-001, August, 2003. 

Figure 13.9 shows the four delayed coker units operated by Conoco, Immingham/England, which have a production capacity for 300,000 tpa of premium coke. 

Coker dmm deheading is a challenge to the safe and reliable operation of the coker unit. Safety issues are generally related to release of hydrocarbons to the atmosphere by opening the top or bottom head in a service dmm [23]. Independent safety systems are also available in the market, namely. Diamond SIS of SIS Tech. 

Exhibit 12-27 illustrates two r ations of the structure generally found In a coker unit. As can be seen, the main operating valve platform is the only platform supported from the elevated concrete de in both arrangements. In one variation, the operator s penthouse is supported from the tqp of tte vessel, along with the entire drill struaure above the penthouse. This layout requires the coke drums to be designed to... 

Carson City, California, USA, Refinery, Fire Pipe leak resulted in fire in coker unit. 

Chem. Descrip. Silicone antifoam Uses Antifoam for delayed coker units... 

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