At present, 92% of methanol consists of natural gas and 2. 3% comes from foreign coal. Therefore, the methanol technology of foreign companies focuses on producing methanol from natural gas. The advanced methanol production technologies widely used in the world mainly include: DAV Y (formerly I. C. I), O PSO E, U hde and L u rgi methanol technologies, etc. The consumption and energy consumption of different methanol technologies are not much different, the main difference is that the main equipment types used in methanol synthesis tower are different.
Technical characteristics of 1 1 DAV Y methanol.
The advantage of DAV Y's low-pressure methanol synthesis technology lies in its excellent low-pressure methanol synthesis catalyst. The synthesis pressure is 5. 0 ~ 100 MPa, and the synthesis pressure of large methanol production plant is 8 ~ 100 MPa. There are three types of synthetic towers: first, the quench synthetic tower, with a large single tower production capacity and an outlet methanol concentration of about 4 ~ 6% VO L. Second, the methanol synthetic tower with internal heat exchange and cold tubes. Recently, a water tube synthesis tower has been developed. Distillation usually adopts double towers and sometimes three towers, considering the setting of steam system. Steam system: divided into high pressure 10.
5M Pa, medium pressure 2. 8M Pa and low pressure 0. 45M Pa。 The waste heat generated by conversion and converter flue gas waste heat are used to generate 10 high-pressure superheated steam. 5M Pa and 5 10℃. High pressure superheated steam is used to drive the synthesis pressure.
Compressor turbine, extracting medium pressure steam for the device.
1.2 L organic methanol technology
The synthesis of L u rgi company has its own characteristics, that is, it has its own patent for synthetic tower. It is characterized in that the synthesis tower is tubular, with by-product steam and L u rgi synthesis catalyst in the tube, boiler water between the tubes, and by-product 3. 5%.
0 MPa saturated medium pressure steam. Because the diameter of large-scale devices, such as the synthetic tower of 2000M TPD is too large, two synthetic towers are often connected in parallel. If the scale is large, use one tubular synthesis tower and then connect another in series.
Cold-tube or heat-tube synthesis tower, or two series of synthesis towers can be used in parallel. The rectification of L 'Urgi process adopts three-tower rectification or three-tower rectification followed by a recovery tower in series. Two-tower distillation is sometimes used. The reboiler heat source of pre-distillation column and pressure distillation column in the process of three-tower rectification comes from the waste heat of reformed gas. Therefore, distillation consumes little low-pressure steam.
Technical characteristics of 1 methanol. 3 to PSO E
TO PSO E Company is a major patent technology supplier and catalyst manufacturer in synthetic ammonia and methanol industry, and its methanol technology features are as follows: BWR synthesis tower (tubular by-product steam) is used in methanol synthesis tower.
Steam), or use CMD multi-bed adiabatic synthetic tower. Its technological characteristics are: using axial adiabatic bed, installing heat exchanger between towers, and preheating boiler feed water or circulating hot water in saturation system by using waste heat. Into the tower temperature is
220℃。 The single-pass conversion rate is high, the catalyst volume is small, the structure of the synthesis tower is simple, and the single-series production capacity is large. The synthesis pressure is 5. 5.0~ 10. Optimize according to the production capacity of the factory. The methanol plant with a daily output of 2,000 tons has a synthesis pressure of about 8M Pa. Adopt three-tower or four-tower (including recovery tower) process technology.
Technical characteristics of 1 4 TEC methanol
The synthesis process adopts ic 1 low pressure methanol technology. Adopt the technology of L u rgi company for rectification. Ic 1 low pressure methanol synthesis catalyst was used in the synthesis.
Synthetic tower: MRF- Z synthetic tower (multi-layer radial synthetic tower) with TEC, and the outlet methanol concentration can reach 8% VO L.
The decline is 0. 1mpa.
Waste heat from methanol synthesis is used to produce 3. 5 ~ 4.0 MPa medium pressure steam.
Steam and medium pressure steam can be used as process steam or used for turbine drive after overheating.
Steam.
1.5 technical characteristics of methanol in Mitsubishi heavy industries.
Mitsubishi methanol technology is similar to the I. C. I process, and its characteristics are as follows:
Super methanol synthesis tower with unique structure is adopted. Synthesis pressure and methanol
Equipment function. The device with a daily output of 2000 tons of methanol has a synthesis pressure of about.
It's 8 o'clock. 0M Pa。
Super methanol synthesis tower is characterized by double sleeves and high catalyst temperature.
Uniform degree, high single-pass conversion rate and the highest concentration at the outlet of the synthetic tower.
14% volume fraction. By-product 3. 5 ~ 4.0 MPa medium pressure steam synthesis tower
The mouth concentration can reach 8 ~ 10% VO L, and the circulation of the synthetic system is higher than that of the traditional process.
The operation is greatly reduced, and the consumption of supplementary gas is the least.
According to the setting of steam system, two or three towers are used for distillation.
1.6 technical characteristics of methanol in wood company
Using I. C. I low-pressure synthesis process and catalyst, the synthesis pressure of methanol plant in 2000 days is 8. 0M Pa。
Synthetic tower: Wood Company adopts an improved air-cooled excited rhombic reactor.
Reactor, isothermal synthesis tower, cold tube synthesis tower.
Arc synthesis tower of CA SAL E company (multi-axial radial synthesis
Tower), the production capacity of a single series can reach 3000M TPD. Synthetic waste
Heat recovery mode: preheating boiler feed water, low equipment investment.
Isothermal synthesis tower: shell-and-tube synthesis tower with by-product medium pressure steam.
The pressure of compressed steam is 3. 5 ~ 4.0 MPa, the maximum production capacity of a single tower can reach
Up to1200m TPD. High investment in equipment.
Cold tube synthesis tower: indirect heat exchange between axial direction and cold tube, single tower production.
The capacity can reach 2000M TPD. Low equipment investment. It can be used.
The comparison of tower distillation, three-tower distillation or four-tower distillation is as follows: two-tower distillation, a
The alcohol recovery rate is 98. The consumption of low-pressure steam per ton of methanol is 1. 2 tons. Three towers
Through distillation, the recovery rate of methanol is 99% and the consumption is 0. 47 tons of methanol is steamed at low pressure per ton.
Steam. Four-tower distillation with methanol recovery tower, the methanol recovery rate is 99. 5%,
One ton of methanol consumes 0. 45 tons of low pressure steam.
1.7 Characteristics of methanol technology in Linde Company
Low pressure synthesis process and catalyst are adopted.
A by-product steam spiral pipe isothermal synthesis tower, wherein
The pressure of boiler water and medium pressure steam is 3. 5 ~ 4.0 MPa, the gas resistance decreases.
Low.
The rest is similar to IC I low pressure methanol.
2 domestic methanol process technology
China is a big coal-producing country, with natural gas and methanol as raw materials.
There is more coal. At present, the output is almost half. There is a single production process.
There are two kinds of methanol: production and co-production. Co-production of methanol in synthetic ammonia plant
In addition to co-production of methanol, tail gas from chemical plants or city gas can also be used.
Methanol co-production
2. 1 domestic methanol gasification technology
The technologies of methanol synthesis from natural gas in China mainly include: 1.
Two-stage steam conversion process and two-stage chemical conversion of pure oxygen come from China Chengda Company.
The technologies of methanol production from coal in China mainly include: fixed bed gas.
Chemistry (including L u rgi furnace, Ender furnace and intermittent gasifier), fluidized bed
Gasification (ash agglomeration gasification), entrained-flow gasifier, has been introduced in recent years.
Texaco coal water slurry gasification and Shell pulverized coal gasification, among which Texaco
Gasification was introduced earlier, with more experience and high localization rate.
Less money. Shell gasification has no experience.
2.2 Household gas purification technology
The desulfurization and decarbonization purification of methanol crude gas is the same as that of synthetic ammonia.
It just doesn't need liquid nitrogen washing. The main purification technology in China is cryogenic A..
Alcohol washing, MDEA, NHD, ADA is also used for desulfurization in small and medium-sized factories.
Decarburization technology of PDS, hot potash, PC and MDEA.
2.3 methanol synthesis and distillation technology
China has developed low-pressure methanol synthesis and distillation technology since 1986.
At present, shell-and-tube by-product steam synthesis tower and
Twin-tower distillation originated from this development, and then the "U" type cold tube combination was popularized.
The column rectification has also developed from two towers to three towers, which can not only produce GB338-
In 2004, high-quality refined methanol can also produce American O-M-232K.
A breakthrough has been made in the treatment process of AA grade refined methanol and alcohol wastewater.
Progress, sewage treatment can be recycled, so the methanol plant is in normal operation.
In the production process, alcohol-free sewage discharge is realized.
In recent years, methanol technology has developed rapidly, and the main trends are as follows:
(1) Production raw materials are shifted to natural gas and hydrocarbon processing tail gas. Jia Cong
Considering the actual situation of alcohol production, using natural gas as raw material is more than using solids.
The input of raw materials can be reduced by 50%; It is economical to use acetylene tail gas.
The effect is more significant. At present, the raw materials for methanol production in the world are all natural.
Gas accounts for about 90%, and coal only accounts for 2%. Domestic in recent years
The proportion of coal to methanol is gradually increasing, which is different from that in China.
About the energy structure.
② Large-scale production, with the largest scale of a single series reaching 2.25 million.
Tons? In 2000, the daily output of single series was 7500 metric tons. After the scale is expanded, it can be reduced.
Unit product investment and cost are low.
③ Fully recover the heat of the system. Steam that produces economic pressure,
Steam turbine and circulating water pump for driving compressor and boiler feed water pump, so as to realize
Comprehensive utilization of heat energy.
(4) adopt new methanol synthesis tower to reduce by-product medium pressure steam.
Energy consumption.
⑤ Adopt energy-saving technologies, such as hydrogen recovery technology, pre-conversion, process, etc.
Condensation saturation technology, combustion air preheating technology, etc. , in order to reduce methanol consumption.
Consumption.