What should we pay attention to when feeding catalytic heat?

Since the raw material preheating temperature has a range, it has little impact on the reaction. It mainly affects the heat balance of the fractionation system. The heat exchange issues of each section of the reflux and the entire fractionation system must be considered, as well as the control of the thermal feed amount and the handling of thermal feed interruptions.

What time did I think of: 1. Since the catalytic material is mixed feed, if it is changed to hot feed, can the raw materials be mixed evenly? Otherwise, it will affect the reaction operation. Is it necessary to add a mixer? ； 2. How to solve the problem of water in raw materials by hot feeding ； 3. How to solve the problem of stable raw material supply with hot feeding ； 4. How to solve the pressure of hot feed raw materials ； 5. What are the emergency measures for hot feed interruption? ；

The device is prepared to use hot feed, the problem is considered very comprehensively, and the learning* Got it!

Personal opinion 1. It is best to set up a boundary feed valve group with cold material coming from the irrigation area as backup 2. Set up a hot and cold feed mixer 3. A buffer tank needs to be set up after the raw materials enter the device, but it is not dehydrated (above 120 degrees) and the prepared raw materials are interrupted 4. Increase the lift of the bottom-reducing pump

The advantages of hot feeding can reduce the energy consumption of the device, such as reducing fuel gas consumption, increasing the steam production of the oil slurry, and using waste heat such as diesel or top cycle as other heat sources.

Hot feeding is an energy-saving method, but you must pay attention to several points when using it.: 1. It is strictly forbidden to bring water into the feed, which will affect the operation. 2. The upstream operation must be ensured to be stable. Large fluctuations are strictly prohibited, which may cause the feed amount to be unstable or the feed components to fluctuate. 3. Since the upstream device cannot be guaranteed to be absolutely stable, it is recommended to add a buffer tank. At the same time, there must be a feed (from the tank area) to ensure the buffer tank liquid level is stable, that is, there are two feeds to ensure that the two feeds are mixed evenly. Mix in front of the static mixer.

This post was last edited by ljx5210 on 2012-6-16 08:30. The usual feeding process: Hydrogenated wax oil (a large amount) + tank area wax oil (a small amount) = boundary area feed -> control valve group -> device raw material tank -> raw material pump -> heat exchange with the oil slurry at the bottom of the fractionation tower -> mixer with the recycled oil -> riser feed valve group -> riser nozzle = ok~ The biggest impact of the feeding situation is that there is water in the tank area, and a large amount of gasification occurs after the gold riser, which seriously affects the reaction temperature and reaction pressure of the riser. It also affects the use of raw material-slurry heat exchangers (heat expansion, flange leakage, safety hazards! ) Everything else is nothing.

We are hot feed, which can increase the heat required for the reaction. It is best to install an electric desalination device, which can remove the moisture from the raw oil.

What is the typical temperature (range) of the hot feed? Is there a large amount of oil and gas after entering the raw oil tank? Will the gas return lines entering the fractionation tower and the gas return lines returning to the refining tank cross each other? Are there frequent large fluctuations in reaction temperatures?

Hot feeding saves energy. Firstly, less pumps are used in the oil tank area. Furthermore, the oil slurry can produce more steam. However, the problems of water in the raw materials, uniform mixing of hot and cold materials, and the stability of the incoming materials must also be solved. There will be no problem in maintaining the cold path feed volume and strengthening the connection with the atmospheric and vacuum devices and dispatching with the oil tank area.

The so-called hot feed is to send the atmospheric and vacuum residual oil directly to the catalysis without passing through the oil, which is beneficial to the energy saving of the whole plant.； You need to pay attention to the following points when putting it into use: 1. The cold exchange equipment from atmospheric and vacuum residual oil to oil products must be continuously moved, and the pipeline needs to be flushed regularly to prevent condensation. It should not be too large, otherwise the residual oil of the oil product will be poured to normal and vacuum pressure, causing the normal and vacuum residual oil to be unable to get out. ； 2. If the residual oil under normal and reduced pressure is supplied to the catalytic converter through the inlet of the oil product residual oil pump, it is necessary to prevent the residual oil pump from not being able to adjust the volume. ； 3. Ensure that the temperature of the residual oil is stable to avoid significant fluctuations in the catalytic fractionation operation.

What time did I think of: 1. Since the catalytic material is mixed feed, if it is changed to hot feed, can the raw materials be mixed evenly? Otherwise, it will affect the reaction operation. Is it necessary to add a mixer? ； Finally, it enters the riser through the nozzle and is blown up by the stripping steam. The mixing will be very uniform and there is no need to add a mixer. 2. How to solve the problem of water in raw materials with hot feed ； There should be no need to install water in the catalytic cracking unit when the raw materials carry water. Generally, there is atmospheric and vacuum pressure, and a dehydration device is installed on the oil side% e' T7 V. S7 @ 3. How to solve the problem of stable raw material supply with hot feed ； In order to prevent fluctuations in feed properties, such as volume fluctuations caused by water, a buffer tank can be set up, but the table must be set carefully, always pay attention to changes in the liquid level of the buffer tank, and make timely adjustments 4. How to solve the incoming pressure of hot feed raw materials ； If there is a buffer tank, the pressure will not have a big impact." Q; ] % I) S3 5. What are the emergency measures for hot feed interruption and self-protection actions?

Will atmospheric residual oil contain water, and will it affect the device? What is the normal slag temperature? After mixing with the raw materials, the first batch needs to exchange heat with the first batch and the oil slurry. How to remove the excess heat? Which refinery is being commissioned? advanced experience * Get off! ! :victory:

Catalytic thermal feed technology has matured and is used in full or part in many devices. Our equipment has long adopted the hot feeding method, resulting in stable production and qualified quality. The specific hot feed materials include normal four-line, minus one-line, minus six-line, propane deasphalted oil, and the spare cold material is wax oil, which is sent by the pump in the tank area to fine-tune the liquid level of the raw material buffer tank of the normal equipment and adjust after some hot materials are interrupted. After the propylene deoiling and wax oil are mixed into the device, it first exchanges heat with the oil slurry, then enters the raw material buffer tank together with several hot feeds from the distillation device, and then exchanges heat with another oil slurry heat exchanger and directly enters the riser. There is a mixer in front of the raw material buffer tank. The temperature inside the tank is generally 220---230°C. Even if there is water, it will vaporize and enter the fractionation tower through the steam return line and will not be brought into the riser.