Summary: delayed caramel wax oil is generally used as a catalyst for catalyzed cracking in the country, but is not welcomed because of its high nitrogen content. Some of the delayed-focal units are designed to expand their production capacity with a minimum input, using small-cycle versus even zero cycles to expand their production capacity, resulting in a higher quantity, lower quality and easier focus of caramel wax oils, thus creating a delayed-focal unit, which is one of our current top priorities。
Keywords: delayed focus; process; operational parameters; long run
0 introduction
Slag oil is processed by hydrogen and carbon decarbonization, which removes asphalt and coke from the slag. Delayed cokering is the most typical decarbonization process, which is technically mature, adaptable to raw materials, with high collection rates of light oil and low investment in equipment, and is an important lightweight method for slag oil. The installation of the central sea petroleum east petrochemical company ltd., which was completed in 2005 and operated for 346 days during the fourth cycle, has many factors affecting the long-term operation of the focal units, mainly operational parameters and equipment, including the nature of the raw materials, temperature, pressure and circulation ratio. Several parameters and issues that affect the long-focal cycle are discussed and analysed below。
1. Raw material properties
Catalysed raw materials are available from a wide range of sources, such as pressure-reducing sludge oil, heat-defunct slag oil, catalyzed slag oil and catalyzed oil. The composition of the slag oil determines the nature of the slag oil and determines the process parameters of the focal unit. Moreover, caramel raw materials are blended into the plasma, which, if mixed with changes in the nature of the ambassador's raw materials, increases the critical reaction temperature of the oil, which, together with the volume of the treatment, increases the gas line of the coke tower at the same temperature as the furnace, increases the foam layer and reacts incompletely, re-inflates into the tara at preheating times, and generates coke deposits at the bottom of the tower, resulting in congestion of the fuel line. On the basis of actual operational experience, however, no changes in the nature of the raw material would be possible to ensure the long-term operation of the plant, without a concentration ratio of more than 15 per cent。
2 temperature
2. 1 export temperature of the furnace
Focused reactions are a combination of thermal decomposition and condensation. The combination of thermal and thermal inhalation results in thermal inhalation, so that the export temperature of the heating furnace affects the depth of the reaction, the temperature is low and the response is incomplete, and the high temperature leads to a focus on the tubes and the great gas wires and reduces the start-up period, while the coke generated is hard to decorate. An export temperature of 490 °c ~ 500 °c is more appropriate and is too high or too low to react to focal and start the work cycle。
2. 2 export temperature of coke towers
Another factor affecting the start-up cycle of the installation is the export temperature of the coke tower. When operational pressures and cycles are fixed, an increase in the export temperature of the coke tower will increase the rate of gas and plaster oil, decrease the rate of gas, decrease the rate of coke production and decrease volatilization in coke. For every 5. 5°c increase in pressure and circulation compared to a given time-critical temperature, the rate of gas oils increased by 1. 1 per cent, and an appropriate increase in the reaction temperature is beneficial for the focus. However, there are disadvantages in being too high, and the higher the temperature of the export, the more likely it is to create a mist band, the greater the foam in the coke towers is brought to the bottom of the large oil and gas lines and distillation towers to focus them and reduce the start-up period of the installation, especially when the amount of processing is high, the higher the foam layer and the higher the temperature of the export is controlled. The method of control is to inject cold oil into the roof, generally into wax oil or light oil, with the export temperature controlled at 425°c。
3 operating pressure & cycle ratio
3. 1 operating pressure
The operational pressure of the system directly affects the harvest rate of the product, increasing the pressure by allowing more heavy oil to remain in the coke towers, increasing the chances of cracking and condensing, reducing the rate of wax oil, increasing the production rate of coke, increasing the length of time that hydrocarbons remain in the towers, leading to secondary cracking, resulting in more gas, gasoline, diesel. Volatile levels of coke have also increased. During low-pressure operations, wax oil fractions can be increased, and the trend towards delayed focal is to reduce operational pressure to increase the yield of liquid products. The operational pressure of my unit is between 0. 15 and 0. 20mpa。
3. 2 cycle ratio
The cycle ratio is an important operational parameter that affects the processing capacity of the device, the nature of the product and its distribution, and the overall tendency of the delayed focal process is to reduce the cycle ratio. When the reaction temperature is constant and the pressure is constant, the cycle affects the proportion of the product and the operating cost of the product in comparison to the dry points directly affecting the wax in the distillation tower. The cycle ratio should be increased in the following cases。
A) reduce the production of caracon wax, which increases the cycle ratio when lower downstream installations are less capable of fully treating caracon wax or when selling at lower prices。
(b) improving the quality of coke. A high-cycle ratio is required for the production of needle and high-quality electrodes。
(c) avoiding the creation of projectile reefs. Improved circulation would avoid the generation of projectile reefs, and the inclusion of some catalytic oil in the feed would also reduce the generation of projectile reefs。
(d) reduced heating stove focus. For some heaters with poor combustion conditions, cycle ratios can be used to adjust the focal speed of the tubes and to extend the start-up cycle。
4 charcoal tower operations
The coke towers are intermittent and slow when preheating, and the old towers are treated with water, so the gas must be small to large, so as to prevent excessive rushing into the towers and affect the back-way operation. An additional key issue that affects the long-cycle operation of the caustic unit is the taroline focal point at the top of the coke tower, which will not only increase the pressure of the causative tower, increase the pressure of the oil and gas line, but also accelerate the bottom of the distillation tower, seriously impact the long-cycle operation of the causative tower, and in actual production we will reduce the casket of the taroline by controlling the height of the foam layer, the temperature of the tower top and the height of the coke。
A) the height of the foam layer is directly related to the temperature of the furnace export, the temperature of the furnace export is high, the foam layer is low and the elevated coke pressure also inhibits the height of the foam layer。
B) injection of blowing agents which can effectively reduce foam layer height。
(c) strict control of the top temperature of the coke tower, excessive temperature, acceleration of the focal rate of the tower's oil and gas lines, general injection of wax oil into the hot oil to control the top temperature, generally at 410-425°c。
5 impact factors of distillation towers
Factors affecting the long-term operation of the focal distillation towers include the concentration caused by the heavy sedimentation of the coke at the bottom of the distillation tower, the failure of the plume-cycle pump, the severity of the coke carried, the uncontrollable quality of the product, and the inability to open the stale seals at the entrance to the pump. The analysis is as follows:
The source of coke at the bottom of the distillation tower is the coke powder at the bottom, but temperature control at the bottom is also important. At 380°c, during the repairs, the bottom of the tower was found to be badly strung and the distillation tower bottom pump was often emptied, indicating a high level of carbon and coke deposition at the pump entrance. We then sum up the solution。
(a) agitation to prevent the deposition of carbon from the coke powder by bringing the current oil feed from the cocal heater below the liquid surface of the distillation tower。
(b) re-engineering of substrate filters to increase the hole to increase the passability of fine coke。
(c) a line from the radiation pump exit to the bottom-coated pump entrance, at the back of the hour, is currently working better。
Atoms of nitrogen, sulphur, oxygen, chlorine, hydrogen, etc. In slag oil, react to generate ammonia and hydrogen chloride in coke, and ammonium chloride crystals at 140°c are deposited together with the coke powder on the pallets to jam float valves, so that the temperature of pump extraction cannot be too low。
6 concluding remarks
Four components of the analysis of the focal material, particularly heavy and newly processed material varieties, must be analysed with regard to asphalt and charcoal. Operation of heating stoves and coke towers. Strict control of the export temperature of the heating furnaces and the export temperature of the coke towers, prevention of caustic catheters and large quantities of coke powder, control of the pressure and hotness of the catheters, prevention of plumes, failure to fill the stoves with water less than 1 per cent of the feed volume, suspension of hot oils and switching of blowing agents at the required time. Get the dispensaries set up. Control the cycle ratio by adding a reaction system to the bottom filter of the distillation tower, and by adjusting the top oil so that the top-dumping temperature is greater than 140°c, preventing the crystallization of ammonium salt. And then, the input to the slag oil stretches into the bottom surface of the fluid, mixing it to prevent the coke from settling in。
