1. Urea production
At present, urea is produced from ammonia and carbon dioxide, which is generated from inexpensive natural gas (off-gas) during the manufacture of ammonia. When urea is synthesized with natural gas as a raw material, however, the available CO2 may be insufficient in view of the balance between ammonia and off-gas CO2. In such cases, CO2 is recovered from the exhaust gas of the steam reformer, which produces hydrogen and CO from natural gas, to supply it for urea synthesis to adjust the ammonia- CO2 balance, thereby enabling urea to be produced in large quantities. A plant Mitsubishi Heavy Industries, Ltd. delivered to Malaysia PETRONAS Fertilizer Sdn. Bhd. (Photo 1) matches this purpose.
Photo 1 Urea plant
2. Methanol production
Methanol is now also manufactured mainly with natural gas as the feedstock. If H2 and CO are synthesized by steam-reforming the natural gas, then the H2:CO ratio is 3:1. On the other hand, for methanol synthesis, the best H2:CO ratio is 2:1, and the output of methanol can be maximized through the recovery of CO2 from steam reformer flue gas, allowing the addition of a meaningful amount of CO2 into the process. At present, active planning for CO2 addition is underway to improve the production capacity of Saudi Arabian methanol plants.
Figure 1 shows a system where, in the process to produce methanol with natural gas as the feedstock, CO2 is recovered from steam reformer flue gas to optimize the H2:CO ratio for methanol synthesis, thereby enhancing methanol production.
Fig. 1 CO2 recovery from flue gas for enhanced methanol production
3. DME (dimethyl ether) production
DME is currently synthesized from methanol. The process is similar to that used for the above-mentioned methanol production.
Fig. 2 CO2 recovery from flue gas-integrated DME production system
4. GTL production
GTL, or Gas-to-Liquid, generally refers to a process to synthesize kerosene and light oil by the Fischer-Tropsch Process (FT Process). For this GTL synthesis, as in the case of methanol, it is necessary to adjust the H2:CO ratio to 2:1 and recover the same volume of CO2 from the steam reformer flue gas for use in the process, also as in methanol production, to enable the H2:CO ratio to be adjusted.
The system recovers and recycles CO2, which does not contribute to the reaction from the FT synthesis process, to the stage prior to steam reforming.
Fig. 3 CO2 recovery from flue gas-integrated liquid fuel production system
Masaki Iijima et al., "CO2 Recovery/Effective Utilization/Fixation and Commercialization," MHI Technical Journal, 39 (5), 286, 2002.
Source: New Energy and Industrial Technology Development Organization (NEDO), Japan Coal Energy Center (JCOAL)
The 10 largest coal producers and exporters in Indonesia:
