Introduction: In the current scenario most countries are concerned about Climate
change. Most Carbon emissions are due to Fossil fuel burning on large scale by
Industries. Now is the time to think about the reduction of carbon emissions by the use
of alternate fuels. In this line, I have studied the use of Hydrogen as a fuel in the cement Industry. Hydrogen is the green fuel and is the most abundant element on the earth. It provides three times more energy than fossil fuels and releases pure water as a byproduct. In cement production, traditional fuels are used in Kilns like Coal, Pet Coke,
and oil to produce cement clinker. Which includes the huge cost of cement production
as day by day availability of fossil fuel is a much bigger challenge. Now the use of
alternate fuels can help to reduce the cement production cost as well as pollution.
Background: Cement is the main element of the construction company and
Infrastructure Housing development needs worldwide. Due to the fast development of
infrastructure, the economy growth cement industries rapidly growing. Along with
growing cement industries facing challenges in energy conservation as well as CO2
emission. As per a study 30-40% cost of production is energy cost which is fulfilled by
a power plant using fossil fuels. The cement production process emitted CO2. Approx.
60% CO2 was emitted from calcination of limestone process and 30% from the
combustion of fuels in Kiln rest 10% in other streams. In most of the industries using
petcock, The Sulphur content in petcock is much higher than normal coal. Because of
this combustion of petcock leads to higher SO2 emissions.
Observation: I have visited M/s Ultra Tech Cement Dalla Unit (UP). There was 3 main
process involved in Cement Production Heating, Calcining & grinding raw material
mainly Limestone (CaCO3) with other material containing calcium, iron oxide, and
silicon carbide. Clinker production takes place at 1450 Deg C in Rotary Kiln. Carbon
Dioxide is released as a by-product during the calcination process, which happens in
the Precalciner at 600-850 Deg C where carbonates convert into oxides. The clinker is
removed and cool from Kiln and then ground into a fine powder and mixed with fly ash
and a small amount of gypsum powder.
Now my focus area is the Rotary Kiln (Combustion chamber) where the calcination
process occurred, and Clinker was formed by heating limestone at 1450 Deg C through
a burner using Pet Coke powder as fuel. After discussion with the area in charge and
operators and OEM, there is an opportunity of using H2 as fuel.
Analysis: I have prepared a flow diagram of the use of Hydrogen in place of Petcock.
As per My study and discussion with the Combustion burner supplier, there are two
possible options available
4.1 Modification of existing burner system to use a small amount of Hydrogen
(Economical)
4.2 New Installation with burner (Capex required)
Currently, in Ultratech 100% Petcock is used in the kiln. Consumption is 10% of clinker
production. It means 1000 kg clinker production required 100 kg of Petcock (90-micron sieve). There is also a limitation of using petcock due to Sulphur content and CO2 emission. In my study, it is observed that we can use a small amount of Hydrogen as fuel by doing an upgradation of an existing burner with a small amount of H2 substitution. The detail of the substitution rate is under calculation. Property of both fuels as below here we can see the heating value of H2 is 4 times of petcock.
Property Pet coke Hydrogen
HHV (High Heating 31.3 MJ/Kg 141.86 MJ/Kg
Value)
Emission CO2 Nil
The above project is feasible and practically possible due to the easy availability of Hydrogen Gas from Grasim Chemicals Ind -Renukoot. It is 23 Km from the Cement plant. Hydrogen is generated as a by-product during the electrolysis process in the Caustic industry. In Grasim, they are using H2 in Hydrogen Boiler for Steam Production and Heating of Molten Salt for flakes production. Requirement: We need to upgrade & install some facilities to handle and store H2 gas as below · Upgradation of Existing Burner·Additional installation of safety instruments and interlocks.
· Installation of High pressure (150 bar) H2 Unloading station from Truckmounted
cylinder.
· Installation of H2 Holder to store H2 gas safely.
· Installation of H2 blower to pump H2 gas at pressure to Burner.
· Installation of Fire and safety system as per guideline.
· Installation piping as per ASME B 31.12
Advantages: The various advantages of using H2 as an alternate fuel in a Rotary kiln
(Ultra Tech Cement – Dalla Unit) are as highlighted here.
Easily available H2 from Grasim 23 Km away.
Excess H2 we can utilize in cement factory.
Reduce H2 venting in the Caustic Industry.
Cost and consumption of Petcock reduced.
Highly Efficient H2 fuel as compared to other fuels.
H2 burning almost zero-emission.
Reduce carbon footprint.
Reduce Sulphur content.
No Noise pollution.
Low maintenance cost.
Economic: Hydrogen is the future fuel. The current consumption is about 6% globally
of total production. Use of Hydrogen as commercial fuel that would be delver to achieveour National Hydrogen Mission launched by Hour Hon’ble Prime Minister on 15th Aug 2021.
Current Petcock Price – Rs – 22000.00 / mt
Hydrogen Production cost – Nil
Hydrogen selling price – Rs. <50.00 / NM3
Transportation Cost for 23 km –
By calculation, it found there is a huge saving in operational as well as raw material costs.
Limitations: A few limitations of the use of Hydrogen are as undermentioned
· Safety as Hydrogen is highly flammable.
· Storage complication due to low volumetric energy density and lightest. we cannot store them in huge quantities.
· Storage of H2 gas required high-pressure tanks (350-700 bar).
· Liquid Hydrogen storage required cryogenic temp. because its boiling temp is -252.8
Deg C.
· Transport through a gas pipeline is not feasible due to forest area as well as a required lot of funds and monitoring.
Conclusion: The use of alternative fuel Hydrogen in small amounts by the cement
Industry in clinker production. On average 100-120 kg of coke is required to produce 1
tonne of cement. Being a part of the Aditya Birla group of Both Plant Ultratech Cement and Grasim Chemicals, we must think about the utilization of Hydrogen in clinker production. This project is possible with a small up-gradation of the existing system, only need to develop some infrastructure for storing, handling, and safety of Hydrogen. Co-processing is the optimum way of reducing energy consumption and cost of production in cement Industries. Here we can utilize the opportunity because of the low transportation cost.
References:
M/s Ultra Tech Cement Plant – Dalla Unit (U.P.)
M/s Grasim Chemicals Renukoot (U.P.)
Alternative fuels in cement Manufacturing by Moses P.M
ASME B 31.12
M/s KHD Humboldt Wedag Int. AG
(*) – Final calculation is being done by technology supplier M/s KHD Humboldt
Leave a Reply