Advances in MTO technology 2: Comparison between MTO and MTP
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This post was last edited by jordan569 on 2013-1-6 20:07. Comparison of MTO and MTP: I. Light olefin yields (carbon conversion, estimated values). Table 1 shows a comparison of the light olefin yields of MTO and MTP technologies. MTO: MTO/OCP – Ethylene: 42% vs. 40%; Propylene: 35% vs. 50%–72%. For hydrocarbons with four or more carbon atoms, the yields are 15% for MTO and 3% for MTP, as well as 23% for MTO. As can be seen from Table 1, MTO technology yields slightly higher amounts of light olefins compared to MTP technology; moreover, when MTO is integrated with OCP technology, the light olefin yields are much higher than those achieved with MTP technology alone. II. Comparison between MTO and MTP Technologies 1. Basis for comparison ◆ Methanol feedstock of 5,000 tons per day ◆ The propylene yield in MTP is 70–72%; other products include ethylene, C4 hydrocarbons, and heavier hydrocarbons ◆ In the MTO + OCP combined process, the overall yield of propylene and ethylene is 87–89% 2. Comparison of MTO and MTP processes Table 2: Comparison of MTO and MTP technologies in terms of process flow MTO + OCP Number of parallel processes: 1 MTO process; 3 olefin cracking processes 1 MTO process; 3 olefin cracking processes Number of reaction steps per process: 1 MTO step, 1 olefin cracking step, and 6 additional steps 1 reaction step for dimethyl ether production Reactor/regenerator: Continuously operating fluidized bed reactor; cyclically operating fixed-bed reactor Final reactor outlet pressure (psig): 2010 Reaction temperature (°C): 400–500; 400–550 Steam dilution: None; 0.5–1 kg/kg of methanol Maximum plant capacity: >1.2 million tons/year to 520,000 tons/year Table 3: Comparison of MTO and MTP technologies in terms of operational parameters MTO + OCP MTP Mixed feed rate, kg/hr: 229,600; 430,500 Mixed feed rate, kmol/hr: 7,310; 15,070 Relative feed volume flow rate: 12.1 Effective reaction rate, kgmol/hr: 10,000; 17,060 Weight ratio of methanol to olefins: 2.63; 3.21 C2 output, tons/year: 317,000; 0 C3 output, tons/year: 317,000; 519,000 Light olefins output, tons/year: 634,000; 519,000 Output of C4 and higher hydrocarbons, tons/year: 30,000; 180,000 3. Comparison of MTO and MTP technologies Table 4: Technical comparison between MTO and MTP MTO + OCP MTP Raw material methanol (100% methanol): 208,333; 208,333 Water content in methanol feedstock: 10,967; 10,967 Cyclooxides: 10,300; 0 Hydrocarbons from C4 recovery: 0; 88,730 Ethylene recycle amount: 0; 42,250 Steam dilution: 0; 80,250 Total raw material for MTO/MTP: 229,600; 430,530 Ratio of mixed feed for olefin cracking: 48,000; 0 From this comparison, it can be seen that MTO technology has advantages over MTP technology in many aspects: the yield of ethylene and propylene using MTO technology is much higher than that of MTP technology ； The plant production capacity of MTO technology is also higher than that of MTP technology. Similarly, the economic viability of MTO technology is also better than that of MTP technology. . Note $ # , $ $
Initially, there were doubts regarding the impact of introducing OCP on the yields of ethylene and propylene; even with the addition of recycle streams, it was unlikely that the yields of these three olefins could be higher than those in a standalone MTO unit. Furthermore, capacity for producing ethylene from ethane in the Middle East is currently expanding significantly; the additional 16 million tons of production capacity is largely intended for the Chinese market. It is also a question whether the price of ethylene will be able to hold up under these conditions.
So that’s how it is; no one has explained it in such detail before. Top 2# dumane
Everyone here is an expert; you’ve learned it. I wonder what the technology used in domestic coal-to-olefins projects is like? How is domestic technology developing?
Is the production capacity of MTP that much lower than that of MTO? Isn’t it said that fixed-bed reactors are more suitable for scale-up than fluidized-bed reactors? Shouldn’t a fixed-bed reactor have a higher production capacity?
I have serious doubts about the data in the original poster’s table. According to Luchi’s recent patent reports, the yield of propylene using the second-generation catalyst is 71%; it’s unclear where the 72% figure in the table comes from For a 520,000 tons/year MTP process, the by-product ethylene production should be 22,000 tons per year; it is impossible for no ethylene to be produced. Another question: doesn’t the MTO process require the by-products to be recycled back into the MTO unit?
I’ve learned it; it’s very detailed and professional. Thank you for sharing
Is the water-alcohol ratio of MTP too high? How can energy consumption be tolerated?
Great topic; I’d like to share my thoughts: 1. In Table 1, the ethylene yield from MTO+OCP is slightly lower than that from MTO alone, which seems counterintuitive. OCP is used to produce C2 and C3 compounds from C4 hydrocarbons; as a result, more propylene is generated while less ethylene is produced. But it shouldn’t mean that the total amount of ethylene is still lower； 2. The ethylene production of MTP is 0, which is illogical; in fact, as stated on floor 6, there is indeed ethylene production, around 20,000 tons per year ； 3. Personally, I think comparing MTO and MTP is fine, but including OCP in the comparison makes no sense – what is OCP? C4 catalytic cracking is a separate reaction; it can be combined with MTO, and of course it can also be combined with MTP ； 4. When comparing the products of MTO and MTP, one should not consider only C3 and C2; the gasoline and LNG produced as by-products of MTP also command high prices in the current market. Of course, they are still cheaper than olefins, but this fact should not be ignored ； 5. Since MTP uses a fixed-bed reactor, a large amount of steam is circulated as a diluent in order to control the temperature rise, resulting in high energy consumption. This problem does not exist in MTO, which employs a circulating fluidized bed. But why isn’t the catalyst wear caused by the fluidized bed mentioned? Both processes have their advantages and disadvantages; only technical economics can determine the ultimate solution. It is believed that the operations in Baotou and Dolun next year will shed some light on this matter, but there is still a long way to go – improvements to the process, efforts to optimize control, operation over extended periods, and the replacement of catalysts...
I doubt the figures from above; could you indicate the source? As far as I know, for MTP with a production capacity of 500,000 tons of olefins, the diameter of the fixed-bed reactor reaches 11 meters. So, for an MTO with a production capacity of 1.2 million tons, even if a fluidized bed is used and the reaction pressure is twice as high, the required diameter must also be quite large, right? Can the fluidization effect of a MTO reactor with a diameter of over 4 meters be ensured? Also, looking at the unit of pressure alone, why is it PSI (g)? Isn’t that a unit related to pounds? 20 pounds should correspond to 0.14 MPa – that can’t be right. The current data is really unreliable.
MTO itself produces both ethylene and propylene; why go to the extra effort to become an MTP? It is almost impossible for the MTP process to proceed without the generation of ethylene. If the primary yield of propylene using MTP technology is not high, it is necessary to reprocess ethylene into propylene. Since the price difference between the two is not significant, such reprocessing increases costs, which makes it uneconomical. Therefore, MTP technology with a high primary conversion rate for propylene is acceptable, while one with a low conversion rate lacks competitiveness.