What is the yield problem of catalytic cracking?

To increase the yield of gasoline, 1. Increase the reaction temperature, 2. Increase the agent-to-oil ratio, and 3. Reduce the amount of recycled oil. Improving the diesel yield is the opposite of this, I don't know if it is right.

Liquefied gas is C3/C4, which is the product of catalytic cracking. Increasing the agent-to-oil ratio increases the reaction temperature. Diesel turns into gasoline, and gasoline turns into liquefied gas. In this way, the diesel yield decreases, and the gasoline yield first rises and then falls.

1. Stop gasoline refining； 2. Explore suitable catalysts and catalyst unit consumption ； 3. Increase the dry point of gasoline ； 4. If there is overlap between gasoline and diesel, you can turn on the stripper steam ； 5. Explore the appropriate depth of response.

The most effective way is to increase the depth of reaction

Is there any way to increase gasoline production while reducing liquefied gas yield?

6# zzl198307 Yes! Use a cracking catalyst with good selectivity, which requires a catalyst that can produce more gasoline and reduce rich gas.

Personally think: The reaction time for catalytic cracking reaction to produce gasoline with the highest yield is very short, 1.0~1.2s is enough. If it is longer, it can only deepen the reaction depth and increase the yield of liquid hydrocarbons, dry gas, and coke. ； Therefore, the reaction time is one of the key points in the control room. Of course, the reaction time is difficult to adjust under the conditions of actual existing devices. New equipment can be implemented by considering new process technologies. In addition, choosing a catalyst is a means ； Increasing the ratio of agent to oil and reducing thermal cracking reaction is an improvement method ； As the reaction temperature increases, the total conversion rate increases, but the gasoline yield does not necessarily increase, and sometimes it decreases, so it needs to be explored in practice.

To increase the depth of reaction and choose better catalysts, can we consider recycling diesel? I remember what was said in petroleum refining engineering. The original raw material for U-tube catalytic cracking was diesel. In fact, there is no need to control liquefied gas. You can use a catalyst with good selectivity and make the produced liquefied gas have a high propylene content (high unsaturated hydrocarbons) and a high isobutylene content. Then 1/3 of your liquefied gas is propylene (mass ratio, volume: 42 %, in our factory, propylene accounts for about 10,000) and isobutylene accounts for 17% (volume ratio), then you will make more money. Think about how much MTBE you can produce (methanol is only about 2,500, liquefied gas is about 5,000, and No. 93 gasoline is about 7,200). In this way, your total liquefied gas leaving the factory will still be reduced, but the value you have to pay will be much higher! ! !

I think what the first floor said is correct. The gasoline yield needs to be increased, that is, the primary conversion rate needs to be increased. Therefore, the reaction temperature and the agent-to-oil ratio should be relatively increased, and of course they must be moderate. Furthermore, on the premise of ensuring the gasoline vapor pressure, the components can be pressed in as much as possible during the stable absorption stage.

The key to improving the gasoline yield is to deepen the reaction depth. In the reaction system, it is to increase the agent-to-oil ratio, and in the fractionation system to increase the gasoline dry point.