Chatting about a few chemical engineering projects

There are many domestic manufacturers involved in the used engine oil processing industry, but few of them are large-scale, and even fewer have the necessary qualifications; the vast majority process used engine oil secretly. 　　Generally, there are two main approaches in this field. One is the production of fuel oil, which is mainly achieved through cracking processes. This is a very traditional method, often carried out in an informal manner; in other words, it’s home-based oil refining, and it can be considered a form of waste utilization. **This approach is not supported as it relies on outdated technology. However, the investment required is low, and coal is used for direct heating. The specifics of this process are well known within the industry, so there’s no need to describe them in detail. Another method is the production of base oils, and there are several processes involved in this. Let’s refer to them as Processes A, B, and C. Negative pressure distillation is used, as well as various heating methods and temperatures; there are also different treatment approaches. Let’s start with Process A. For those models on the market that use Route A, the boiler burns natural gas; first, oil A is used to maintain a temperature of around 200 degrees (there is already residual heat from the initial startup phase), which allows the light components inside to evaporate while the residues settle. Subsequent oil is fed into the reactor, heated to 350 degrees, and distilled under negative pressure. It is generally divided into two sections: the first one contains fuel oil, while the latter contains base oil. Next is oil washing, using the sulfuric acid method or other chemicals; I won’t mention their specific names. There are many different routes here, options for selecting equipment or manufacturing it oneself, and there are many pitfalls involved. Although this process seems simple, almost no one in China has managed to implement it successfully to date.

Speaking of Route B, it’s all about something fancy and high-end, but in reality it’s useless; hydrogenation is involved, haha. At this point, I have to spit on those so-called design institutes and technology providers in China – they definitely cheat people, and it’s a huge scam that can haunt one for a lifetime. Generally, those who try to make money from used engine oil are old-fashioned people who have some money and want to go for a more sophisticated approach, such as distillation and hydrogenation. They assume that this will result in high-quality products. But after a few rounds, they usually end up losing 100 to 200 million, forcing them to start over. The composition of used engine oil is very complex, and real chemical engineers disdain doing such work. Those with lower skills think that it’s no different from normal vacuum distillation and hydrogenation Catalyst poisoning. There are no successful cases in the domestic market. If that friend knows of any successful cases, please let me know. Route C involves distillation using a vacuum tower, with staged depressurization using alkaline solutions; however, the oil obtained still requires acid and alkali treatment, and there is a lot of waste residue generated. The technical complexity of this method is not high, and there are manufacturers capable of carrying out continuous production. 　Route D involves solvent extraction; this method can make use of pyrrolidone or furfural. Ether amines present cost issues, and there are few successful manufacturers in China. The regeneration of pyrrolidone and furfural represents a significant technical challenge, as it is difficult to control costs. It is also prone to poisoning. There are also some other routes, which are branches of the ABCD routes; I won’t go into detail about them all. Here I would like to mention a few key technical issues. The first is the heating method: coal, natural gas, and fuel oil (methanol); the requirements for boilers vary in each case ； Second is the heating medium; traditionally, heat transfer oil is used, or lava can be employed. This also involves issues related to the design of the boiler, as well as the method used to heat the oil. There are many pitfalls involved, and film evaporators are sometimes used as well (a very complex solution that was a common mistake for many people in the early days). There are also some key issues that I haven’t discussed in detail, such as the method of heating the lava, how to refine the resulting product, and what the appropriate heating temperature should be – all of these are crucial. Friends who are interested can discuss it together; it gets quite interesting here.

Speaking of boron trifluoride, the traditional production method involves the sulfuric acid process, and there are only two or three companies in the country that produce this product. The benefits are excellent these days; boron trifluoride is a truly remarkable substance. For many chemical synthesis processes that were previously quite complex, the use of boron trifluoride simplifies things significantly, resulting in high conversion rates. I have a simple process for producing boron trifluoride here; the cost is extremely low, and there is no waste at all. The sulfuric acid method generates a lot of waste acid, which is difficult to handle and causes significant pollution. 　　I am currently synthesizing a product using boron trifluoride; the results are not yet known. We’ll find out in a month whether it can be industrialized. Those who are familiar with synthetic lipids or ether amines can share their thoughts. Let’s talk about the next project, an old one that involves dye intermediates – specifically, the conversion of phthalo blue, which is used in large quantities. Currently, too much acid is used in this industry; sulfuric acid is cheap, but it causes severe pollution. In fact, there is a very simple method that can eliminate the need for such large amounts of acid. Regarding rubber recycling projects, I came across a company recently; those who are interested in this industry can discuss it.

Used engine oil is considered hazardous waste, and disposing of it privately is illegal.

Under the current domestic environment focused on safety and environmental protection, it is difficult to get approval for these projects; not to mention carrying out such activities secretly.

For the used engine oil project, there are those who do it well; the original poster can stay in touch via QQ

Under the current emphasis on environmental protection, such projects must be approached with caution; otherwise, there will not be enough funds for environmental protection efforts, and the amount of used engine oil is quite large ?

I just left a design institute and am now working at a factory that recycles used engine oil. I’m currently modifying a unit there; the original unit used molecular distillation technology, which simply doesn’t work properly

Boron trifluoride: How to ensure environmental sustainability? The hydrogen fluoride produced is quite troublesome and extremely dangerous.

Baosteel has one that has hardly been in use since it was built.