The concept of refractories has evolved over time
The concept of refractories has evolved over time

The concept of refractories has evolved over time

Sumanta Mukhopadhyay, General Manager - Technical, Dalmia Refractories Ltd
Significant energy saving is possible through judicious choice of refractories, with an aim to reduce shell temperature without compromising on lining quality in the critical areas of the kiln, says
Sumanta Mukhopadhyay, General Manager - Technical, Dalmia Refractories Ltd.

Being one of India's oldest and leading refractory companies, can you tell what the latest trends in refractories are for cement?
Two aspects have changed in recent times - first is product/innovation related and second relates to the concept of refractories. In the first case, most cement makers are now moving towards adoption of alternate fuels like pet coke, waste oil, tyre chips, municipal waste, animal meal, paper etc. that allow for suitable and environment friendly waste disposal of highly corrosive material. Usage of these fuels often creates a host of problems such as ring formations, unwanted coatings and degradation of refractories in the pyro-processing system. Refractory makers now have to take into account the usage of these alternate fuels and tailor products accordingly and/or bring in innovations that fight the challenges posed by these fuels.

Second - the concept of refractories has evolved over time. Earlier customers wanted 'products'- suitable bricks for their kilns and other cement-making equipment. Today, given the pressure on margins and excess capacity, customers are looking for solutions that can reduce their cost of production. Hence, their expectations from refractory experts are optimum solutions that meet their production objectives as well as help in cost savings.

Being market leaders, Dalmia is well-positioned to meet the requirements posed by both these trends. Especially in the second case, Dalmia is one of the few companies that have the knowledgebase and a dedicated technical service team that can evaluate existing usage conditions, recommend solutions and help customers transition to an optimised lining for their kiln.

Why do we need to optimise?
Substantial cost savings is possible through optimisation of refractory lining. In the optimisation process, critical and non-critical areas of the kiln are identified along with an assessment of safety factors, the kiln lining history etc. and an optimised lining recommendation is developed. Our experience and studies have shown that significant reduction in annual refractory cost is possible through careful implementation of the lining optimisation concept. Apart from reduction in refractory cost, optimisation can also help in:

  • Fuel savings by reduction of heat loss
  • Savings in electrical power due to reduction of refractory load

What does the lining optimisation process entail?
Lining optimisation is a 360-degree concept where the first step entails undertaking an assessment of risk factors by studying the customer's production process and identifying the critical and non-critical areas of kiln. Thereafter, a cost-analysis is done of existing over-engineered refractory products vis-a-vis proposed products, keeping in mind safety factors. Providing products and technical support in installation follows, alongside continuous analysis of refractory performance and evaluation of savings.

What are your latest offerings for the cement industry?
Given the growing usage of alternate fuels, Dalmia is offering a range of specially engineered high alumina bricks that can fight coatings and extend refractory life in coating prone areas. In the absence of superior, locally manufactured coating repellent bricks, customers had been using expensive imported bricks. Dalmia has helped bridge this gap.

There was a similar need in the market given the absence of locally made basic bricks.
Dalmia Refractories, a part of the Dalmia Bharat Group has another refractory leader 'OCL' in its stable that has been making basic bricks for steel for over 5 decades now. Drawing from our internal experience and manufacturing capabilities, Dalmia now offers locally manufactured basic bricks for cement industry that are at par with the best in the world in terms of quality, finish and performance.

We are now expanding our castable range and have a dedicated plant at Katni to make a wide variety of products. We have also tied up with Seven Refractories, a boutique European monolithic refractory company to bring advanced products and technologies to Indian cement makers.

With cement makers adopting green production techniques, are you also offering any environment friendly solutions?
We are working in the area of energy efficiency as cement kilns lose substantial energy through radiation from kiln shell. Significant energy saving is possible through judicious choice of refractories, with an aim to reduce shell temperature without compromising on lining quality in the critical areas of the kiln.

Once again optimisation of kiln lining is a way forward because it helps in energy savings by assessing the criticality of usage conditions and recommending appropriate alternatives in place of the highly conductive basic bricks in relatively less critical zones. Dalmia-OCL has a range of special alumina bricks like DALBURN, DALSUPREME which are made with special additives to achieve desired properties and work suitably as replacement for basic bricks. For instance, DALBURN is suitable for burning and upper transition zone of kilns with pet coke firing and DALSUPREME is a good option as replacement for basic bricks for upper transition zones of kilns with higher thermal load.

Apart from this, Dalmia OCL has developed basic bricks with special additives like Zirconia with enhanced thermal properties and reduced thermal conductivity. These bricks are suitable in reducing radiation losses in critical areas like upper and lower transition zones of cement kilns under pet coke and alternative fuel firing. We have also introduced a special energy-saving refractory brick called 'ALITE' which has very low thermal conductivity and can be used for inlet and calcining zone of kilns. Apart from low thermal conductivity, ALITE has high resistance to alkali and sulphur attack, good cold crushing strength and low density which helps in reducing total refractory load in the kiln.

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