RK-07 DME catalyst is applicable for methanol dehydration to generate DME (dimethyl ether), since catalyst put into market in 2008, the total amount of reference list is up to 30 plants include 50 reactors.
The catalyst is definitely acceptable by plant users based on high activity, superior selectivity, excellent service life, easy operation procedure and low unit consumption.
1. Physical properties
Composition: Alumina oxide and additives
Appearance: white strip
Bulk density: 0.6±0.05 Kg/L
Crush strength: ≥80 N／cm
2. Operation conditions and technical performance
Raw material: refined methanol / crude methanol
Space velocity (liquid): 0.5-2h-1
Temperature: inlet 220-280℃
Methanol per pass conversion rate: 75-85％
DME(dimethyl ether) selectivity: ≥99％
3. Production operation characteristics
RK-07 per pass conversion ratio has been proved 5-10% higher than other catalyst in Hubei Tianmao and Datang Duolun plants, The actual per pass conversion ratio is up to around 85%.
RK-07 is easy to operate in process of actual production running, directly temperature rise by methanol gasification, also temperature rise by N2 gas circulation and steam gas are also acceptable. Temperature rise by N2 gas is most proposed.
3)Low temperature for initiation of activity
RK-07 show excellent activity when inlet temperature at 180℃ in Hubei Sanning plant, which proved catalyst has superior low temperature for initiation of activity.
4)High catalyst selectivity
DME (dimethyl ether) production is no peculiar smell in plant reference using RK-07 catalyst.
RK-07 successfully replaced imported catalyst in Datang DME plant with capacity 1.2 million ton per year. The former stage process is 1.2 million DME facility of Datang MTP process, which strictly require catalyst show high performance due to inlet temperature is up to 220℃ and outlet temperature is up to 420℃, catalyst selectivity required more than 99%.
5)Low unit consumption
Usually methanol unit consumption is 1.40-1.41 in process of using RK-07 catalyst.
4. Catalyst operation
Catalyst should be taken sieving operation prior to loading, so as to remove
tiny particles created during transportation.
Loading procedure should be designed according to reactor dimension and
type. Then handle seal up and pressure testing to be confirmed qualified.
Sweep system by N2 gas until system oxygen content less than 0.2%.
2)Start up production
System pressurized to around 0.3Mpa. Start reaction system, start methanol gasification and heating facility, preheat methanol to 240-260℃, and flow volume should be 20-30% normal production ratio.
Rise catalyst bed layer temperature gradually to reaction starting. Timely control methanol inlet temperature and flow volume so as to catalyst bed layer hot spot temperature is less than 360≤360℃, and reaction pressure reach designed value 0.7Mpa.
Low production ratio running consist of 10-20 hours until to all stage units such as distillation in normal operation condition, then gradually increase production ratio to 100% production.
During period of initiation of reaction, low production ratio and 100% production, strictly control bed layer hot spot temperature not exceed 360℃
Heat exchange reactor
System pressurized to around 0.3Mpa.
Start electric furnace, heat medium by N2 gas and hot steam, preheat reaction system so as to catalyst bed layer temperature to 240-260℃ After kept in a stable period, stop N2 gas and hot steam circulation, facility will be transfer to feeding condition.
Take 20-30% of normal methanol feeding ratio, then reaction start up, bed layer temperature risen. Control inlet temperature and gas flow, and kept bed layer temperature steady. Gradually increase methanol feeding ratio to 100% production.
In the process of reaction initiation, low production ratio and 100% production ratio, keep bed layer hot spot temperature not exceed 360℃.
3)Routine shut down
Stop methanol gasification convertor heating, stop methanol feeding, turn off gasification inlet. Discharging system pressure, then swept system by N2 gas. When the organic content of end gas is less than 0.2% based on volume, shut down convertor outlet so as to make it natural cooled and keep it in positive pressure condition.
If the catalyst needs to be unloaded, the convertor should be cooled to atmospheric temperature, then discharge convertor gas and unload catalyst.
If emergency shut-down required, following operation should be taken:
Stop methanol feeding, stop methanol gasification heating, turn off gasification inlet. Then decrease distillation tower temperature, discharge system pressure, sweep system by N2 gas
After stop production, sweep reaction system by N2 gas. Turn down N2 gas flow volume since the organic content of end gas is less than 0.2% based on volume. When convertor temperature decreased to atmospheric condition, operate catalyst unloading.
6)Spent catalyst disposal
The spent catalyst should be delivery to qualified company to handle.
7)Others matters needing attention
Pay attention to reactor temperature control to prevent from temperature runaway.
In case of PH value is less than 7 in feeding methanol, it can be adjusted with sodium hydroxide to be controlled at 7-8.
Prevent catalyst from moisture and pollution during transportation and storage, etc.