Page 179 - CW E-Magazine (17-6-2025)

Special Report

Table 6: Power requirement for each Table 7: Production potential in Indian steel plants for methanol and ammonia
gas stream [mtpa]
Stream Pump power Capacity utilisation Methanol Ammonia Methanol only
(kW/THM) 100% 8.99 5.43 26.55
Feed COG 25.98 75% 6.743 4.073 19.91
Gases after steam 32.85 50% 4.495 2.715 13.28
reforming 25% 2.247 1.357 6.64
Feed BFG 121.95
BFG after CO 88.35 2.84 kg CO per kg of ammonia(11). Further CO, CO reduction
2
2
2
removal There is additional 820,000 tons CO 2 Table 5 indicates surplus CO of
3
Total 269.15 emission savings per year. 236.53-m /THM, and surplus CO of
2
321.96-m /THM. Some options for
3
As only 15% of BFG quantity is Estimated gas usage for production using this surplus are indicated below.
used for production of ammonia and (Case 1)
methanol, the power consumption is  N – 1.554-mtpa or 1,243.07 mscm/ Direct use of methanol and/or

2
only 31.5 kW. For ammonia produc- year. ammonia is well known. Conventional
tion, 54% of hydrogen is consumed,  CO – 1.443-mtpa or 1,154.46 mscm/ thinking is to use green hydrogen to

and the remaining is used for methanol year. covert CO/CO to methanol. But green
2
synthesis.  CO – 2.113-mtpa tons/year or hydrogen is expensive – 2.5-3.5x the
2
1,075.71 mscm/year. normal cost – and requires subsidies.
Power consumption for gas separa-
tion for Case 1 is as follows: Potential carbon reduction Of more signifi cance is the utilisa-
 Ammonia production = Power for CO used is converted to equivalent tion of surplus CO and CO to produce
2
steam reforming + part of BFG = CO . Of the total CO and CO obtained other chemicals such as phosgene,
2
2
49.73 KW/tonne of NH . from COG and BFG, approximately, acetic acid, and dimethylformamide.
3
 Methanol production = Power for 10.5% is consumed based on the Phosgene is a very important chemical
Feed COG + part of BFG = 40.6 above-mentioned process route. used for manufacturing isocyanates
KW/tonne of methanol. used in agrochemicals, TDI and MDI
Methanol alone (Case 2) appears to (both used in manufacture of polyure-
Potential give almost three times higher CO use thane foams), etc. Phosgene safety is
2
The hot metal production in Blast over Case 1. But considering the CO assured as it can be produced on de-
2
Furnace plants in India is 87.045-mtpa. avoided when producing ammonia then mand without need for storage.
The existing plants may be utilizing the CO equivalent is tilted towards
2
the gases in many ways; if produc- combined production. Methanol can also be converted to
tion of chemicals is planned, suitable acetic acid by reaction with CO.
changes have to be made, or in case of In Case 2 as only methanol is pro-
new plants these have to be incorpo- duced using CO, the carbon utilization Asahi Kasei Corporation(12) has
rated at FEED stage. Table-7 indicates increases to 28.6%, which is almost industrialized processes where ethylene
the potential for methanol and ammonia three times higher than Case-1. CO oxide reacts with CO to produce ethy-
2
production at different levels of used for the production of methanol is lene carbonate. The ethylene carbonate
utilization. 218.32 m /THM or 9.746 kmol/THM. is reacted with methanol to produce
3
Table 8: CO savings Case1 and 2
Even if 40-50% of the potential is 2
realized, the quantum of production Capacity Methanol CO Ammonia CO Methanol CO
2
2
2
would be substantial. utilisation savings (mtpa) avoided (mtpa) savings (mtpa)
100% 1.302 15.47 3.845
Hydrogen produced by steam 75% 0.95 11.61 2.88
reforming is 85,320-tpa. If natural gas 50% 0.65 7.74 1.92
consumption is foregone for ammonia
production, the savings is equivalent to 25% 0.325 3.87 0.96
Chemical Weekly June 17, 2025 179

Contents Index to Advertisers Index to Products Advertised