What’s Petcoke ?
Cocking is a thermal cracking process characterized by long residence time and the manufacturing of petroleum coke (Petcoke), a heavy carbon residue. Petcoke is produced by thermal cracking of vacuum residue that’s produced from crude oil.
In a petroleum refinery, atmospheric and vacuum distillation processes take away from the crude the oil the elements that boil as much as about 500oC. The distillation process separates the lighter a part of the crude oil into fractions that are then processed into useful refined merchandise such as LPG, petrol, kerosene, diesel, and many others. The part of the crude oil which does not boil off during the distillation course of even below vacuum is thought because the vacuum reside. The vacuum residue consists of heavy, viscous, complex hydrocarbon molecules.
The coking process converts the vacuum residue into gas, liquid and solid merchandise. In delayed coking, the heavy feedstock is heated in a tube nonetheless and pumped as quickly as doable to insulated drums where it the massive molecules are cracked into smaller molecules and residue, producing gas, liquid products and coke. The time period ‘delayed’ comes from the delay between heating and coking. As coke buiilds up in the drum, the lighter merchandise of cracking are recovered as overhead vapours and are taken to a fractionator for separation into varied products.
Petcoke yield is mainly dependent on the carbon content material of the feedstock, whereas the structural high quality of the Petcoke is influenced chiefly by the kind of feed, i.e., virgin crude or cracked merchandise. Gas grade Petcoke is produced from vacuum residues which have high sulfur contents. Excessive sulphur Petcoke is used as gasoline whereas low sulphur Petocoke is used in producing anodes.
Fuel grade Petcoke typically replaces iignite and coal.
How does Petcoke compare with Lignite ?
Lignite is a natural product and a fossil fuel Lignite is discovered at and round Panandro, Rajpardi and Bhavnagar in Gujarat Lignite is the primary stage of conversion of wood and biomass product into coal. It has very excessive moisture content material about 30-forty%. The volitile conteint can be very excessive, about 30-forty%. Fastened carbon is much less unlike Anthracite and Petcoke. Sulphur content material is 3.Zero-5.Zero%. Calorific vlaue of lignite is very low, about 2800-3800 kcal / kg where as calorific value of Petcoke is 8200-8500 kcal / kg. So, on heat equivalent foundation, 2.5 to 3 kg of lignite is changed by 1 kg of Petcoke. It signifies that whereas for the same heat equivalent just kg of Petcoke with about seventy five gm of Sulphur is injected into the furnace. Hence, the era of SO2 with lignite is 1.4 times higher as in comparison with Petcoke. When Petcoke is used as a fuel, limestone is generally injected into the furnace to absorb SO2 from the flue gasoline as soonas it is genrated. Some users provide wet lime scrubbers to absorb SO2 from the flue fuel. Limestone injection is never carried out throughout lignite firing. Thsu the emission of SO2 is much lesse with Petcoke as in comparison with lignite.
How does Petcoke examine with Coal ?
Specifications of Petroleum Coke (Petcoke)
RIL is manufacturing three grades of Petcoke, Grade A, Grade B and Grade C Whose specifications are given beneath.
Petcoke Grade A
Petcoke Grade B
Petcoke Grade C
Air Dried Foundation
Gross Calorific Worth
- 7.0, max.
- 7.5, max.
- 35, min.
- Eight.0, max.
- 1.Zero, max.
- 8 min.
- 87, min.
- 8200, min.
- Eight.5, max.
- 4.0, max.
- 6.Zero-7.0 Grade A
- 7.Zero-7.5 Grade B
- 7.5-8.5 Grade C
- 38-45 for Grade A & Grade B
Petcoke can be used as a substitute of coal / lignite. It may be utilized in mix kind together with coal / lignite or one hundred% in AFBC / CFBC boilers.
AFBC Boilers are capable of absorbing SO, and prohibit BO, emissions ot the desired levels by limestone injection system.
Ash content material in Petcoke is way lower than coal / lignite. Hence particulate emissions are always lower as in comparison with coal.