石油焦基本知识汇总Word文档格式.docx

1、The residue remaining when all of the coke is burned off. It is mostly metals and silica.Calcineable cokePetroleum coke that qualifies to be calcined, i.e., generally non shot and low in metals that will qualify for anode grade. Calcineable coke is generally referred to as the available supply to ca

2、lciners. Also known a s green coke （see same）.Calcined cokePetroleum coke or green coke （see same） that has been processed in a calciner （see same）CalcinerA large rotary kiln （similar to a cement kiln） that drives off the moisture and volatility of green or calcineable coke （see each） so that the co

3、ke can be used for aluminum anodes, or titanium dioxide applications. The kiln receives the coke at the higher end where the coke flows downhill as the kiln rotates. At the same time heated air counterflows uphill from the lower end, driving off the moisture and volatile materialCarbon rejectionCrud

4、e oil contains a wide variety of hydrocarbon molecules, ranging from a single carbon atom （methane） to very long chain molecules. The lighter molecules that make up gasoline, jet and diesel contain a lower ratio of carbon to hydrogen than the heavier molecules. In order to convert the heavier molecu

5、les to lighter products, the heavier molecules must not only be cracked, but the excess carbon must be removed to reduce the carbon to hydrogen ratio of the cracked material.Circulating Fluidized Bed （CFB） BoilerA type of boiler where the solid fuel is fluidized in a vertical furnace. The advantage

6、for the pet coke industry is that 100% very high sulfur coke can be burned. The sulfur is removed by addition of limestone in the bed which forms an easily removable calcium sulfate ash. CokerA refinery processing unit that converts the residual oil from the crude unit vacuum or atmospheric column i

7、nto gas oil that can be made into light products （gasoline, jet and diesel）, weak （i.e., low energy content） fuel gas and pet coke. There are 3 types: Delayed, Fluid, and Flexi （see each）. These are all basically carbon rejection schemes （see same）.Delayed cokerA type of coker whose process consists

8、 of heating the residual oil feed to its thermal cracking temperature in a multi parallel pass furnace. This cracks the long chain heavy carbon and hydrogen molecules of the residual oil into coker gas oil and pet coke. Both are in a liquefied form in the mixture as it leaves the furnace and enters

9、the coke drum.In the drum, the coker gas oil vaporizes and separates from the mixture. It is directed to a fractionation column where it is separated into the desirable boiling point fractions. The liquid coke solidifies in the drum as it cools and the velocity slows down.After the drum is full of t

10、he solidified coke, the hot mixture from the furnace is switched to a second drum. While the second drum is filling, the full drum is steamed to further reduce hydrocarbon content of the pet coke, and then water quenched to cool it. The top and bottom heads of the full coke drum are removed, and the

11、 solid pet coke is then cut from the coke drum with a high pressure water nozzle, where it falls into a pit for reclamation to storage.Larger cokers have several pairs of tandem drums.DemurrageContracts for rail cars, trucks and marine ships always include a specified time limit that the respective

12、vehicle or ship will take to unload or load. The penalty for delaying beyond the time allowed is also specified in each contract. Upon completion of the actual load or unload, the vehicle or ship owner presents the customer with a demurrage bill specifying the time delay beyond the allowance, reason

13、s for it and the $ penalty. Dry metric or short tonA unit of measure for billing pet coke weight, which refers to the gross coke weight adjusted for excluding the contained moisture content. To get this measure, the coke must be tested for moisture content （see same）. Calcineable coke （See same） is

14、frequently measured in these units. Also see Wet metric ton.Energy contentThe energy content of coal and coke is usually specified in either BTU/lb or Kcal/kg. It is measured in a calorimeter that literally ignites the test sample and measures the temperature rise of the water bath surrounding it.Fl

15、exi cokerThe flexicoker adds a third vessel, a gasifier, to the fluid coker to gasify the purge coke into a weak fuel gas. Coke is made in 3 areas: purge coke from the heater, and both larger and smaller recovered coke fines from the weak gas scrubbers. It is a “flexible” coker in that the gasifier

16、can be run to make either more coke or more weak fuel gas.Fluid CokerA fluid coker produces more light product yield and less coke but the coke is higher in metals and harder than a delayed coker. The process is a continuous fluidized bed consisting of a reactor and a burner vessel. Feed is sprayed

17、onto seed pellets of coke in the reactor where it is coked. Purge coke is drawn off the burner vessel.Fuel grade cokePet coke that competes with steam coal as fuel for a furnace, boiler or cement kiln. If the coke contains low metals, it may qualify as anode grade （see same）. The choice of whether a

18、 coker makes fuel grade vs anode grade is dictated solely by the crude slate and the metals content therein.Green cokeUsually refers to calcineable coke, i.e, potential anode quality coke that still contains moisture and volatile material, i.e, before calcining. Hargrove Grindability Index （HGI）A me

19、asure of the relative hardness of the coke in terms of resistance to grinding. An HGI below 35 usually means a very hard coke requiring considerable grinding before it can be properly sized to meet burner nozzle specifications for the pulverized feed to the furnace where the coke will be burned. An

20、HGI above 65 is usually recognized as a soft coke that will grind very easily.Loss on Ignition （LOI）Coke that is added to coal in a furnace originally designed for coal, may not fully burn in the furnace. Some coke particles escape the flame envelope and are caught by the precipitators or bag houses

21、. This LOI results in reduced furnace efficiency and some carbon contamination of the flue gas ash recovered.Metals contentThe distillation processes of the atmospheric and vacuum columns result in almost all of the metals content of the crude to concentrate in the residual oil （the coker feed）, and

22、 then further concentrated in the coker. Generally metals are not a problem to fuel grade coke buyers, other than vanadium to some. However anode grade coke buyers prefer low metals as the metals tend to reduce the efficiency of the anode in the aluminum smelting processMoisture contentPet coke as c

23、ut from a coker contains roughly from 7-10% moisture which the coke picked up from the steaming and quench operations. It is measured by heating a 100g sample of ground coke, until the moisture is gone, and then re weighing. See Wet metric tons and Dry Metric tons.Needle CokeA special quality coke p

24、roduced from aromatic feed stocks. It has a crystalline structure with more unidirectional pores. It is used for high quality graphite anodes such as for electric arc furnaces in the steel industry.Shot cokeDue to mechanisms not well understood, the coke from some crudes forms into small, tight, non

25、 attached clusters that look like pellets, marbles or BBs. It usually is a very hard coke , i.e., low HGI （see same）. Such coke is less desirable to the end users because of difficulties in handling and grinding. It is also less desirable for calcineable coke because the shot tends to “pop” in the k

26、iln reducing the thermal stability.Sponge cokeMost delayed coke is in a form that resembles a sponge, i.e, sort of bubbly looking.Sulfur contentSulfur in crude naturally distributes itself throughout the range of the crudes hydrocarbon molecules. However, the residual oil and coke usually attract a

27、disproportionately higher Sulfur percent. Also, as most low sulfur crudes become extinct, refineries will run higher sulfur crudes thereby increasing the coke sulfur. Volatility or VCMPet coke from a coker contains a small amount （10%） of light hydrocarbons trapped in the pores of the coke. The amou

28、nt of such volatility is generally related to the how hard the coker furnace is driven: hotter furnace outlet temperatures result in more hydrocarbons driven off and therefore lower volatility.Wet metric tonFuel grade coke is typically sold in these billing units which is at a standard 8% moisture.

29、If the coke tests for a higher %, the billing weight is adjusted accordingly. 2 石油焦石油焦（Petroleum coke）是原油经蒸馏将轻重质油分离后，重质油再经热裂的过程，转化而成的产品，从外观上看，焦碳为形状不规则，大小不一的黑色块状（或顆粒），有金属光泽，焦碳的颗粒具多孔隙结构，主要的元素组成为碳，占有80wt%以上，其余的为氢、氧、氮、硫和金属元素。 石油焦具有其特有的物理、化学性质及机械性质，本身是发热部份的不挥发性碳，挥发物和矿物杂质（硫、金属化合物、水、灰等）這些指标決定焦炭的化学性质。 2.1 石

30、油焦分类及性质 石油焦的形态随制程、操作条件及进料性质的不同而有所差异。从石油焦工场所生产的石油焦均称为生焦（green cokes），含一些未碳化的碳烃化合物的挥发份，生焦就可当做燃料级的石油焦，如果要做炼铝的阳极或炼钢用的电极，则需再经高温锻烧，使其完成碳化，降低挥发份至最少程度。大部份石油焦工场所生产的焦外观为黑褐色多孔固体不规则块状，此种焦又称为海绵焦（sponge coke）。第二种品质较佳的石油焦叫 做针状焦（needle coke）与海绵焦比，由于其具较低的电阻及热膨胀系数，因此更适合做电极。有时另一种坚硬石油焦亦会产生，称之为 球状焦（shot coke）。这种焦形如弹丸，表面积少，不易焦化，故用途 不多。石油焦具有其特有的物理、化学性质及机械性质，本身是发热部份的不挥发性碳，挥发物和矿物杂质（硫、金属化合物、水、灰等）这些指针决定焦炭的化学性质。物理性质中孔隙度及密度，决定焦炭的反应能力和热物理性质。机械性质有硬度、耐磨性、强度及其它机械特性，颗粒组成及其它加工和运输、堆放、贮存等性质影响的情形