Cement Energy and Environment

4.0 Enhancing energy efficiency Key Barriers identified in enhancing energy efficiency: High capital cost of retrofits that are required to be made and longer payback period makes the adoption of the technology less popular. For instance, high pressure roller press can be introduced as a pre-grinding step for the ball mill in order to decrease specific power consumption in finish grinding and/or to increase the output of finish mill. Grinding capacity of finish mill increases by about 30%. Specific power consumption decreases by about 10%. Reductions in specific energy consumption are reported in the range of 7-24 kWh/t-cement. However, it is stated that the addition of the roller press as a pre-grinding step enhances requirement of overall attention required for this process and makes the activity more time consuming. Plus, the payback of the technology is considered to be more than 3 years. Energy Service Company (ESCO) model is non-existent in India. This is considered to bring along with it technology and finance supply for cement companies which is considered to be helpful in implementation of new technologies in plants. Company- There are four technology products like coolers, heat shield and Variable Frequency Drive in dampers that can collectively reduce the energy consumption by 25 Kcai/Kg. The detailed description of the products is described below. However reportedly the payback period is estimated to be more than 3 years and its installation results in halting of plant that adds up to the cost that is considered to be extremely high and acts as resistance to implement the same in the plants. :,... Coolers: The recirculation of hot cooling air from the cooler exhaust back into the cooler is possible. The division of the undergrate compartments and the fact that there are no heat sensitive parts under the grate, make the recirculation of hot air possible without drawbacks in that area. :,. Heat Shield: The features of heat shield area as follows: (i) It maintains a constant kiln hood pressure for stable flame and kiln operation. (ii) Separation of preheated air and vent air. (iii) Higher heat recuperation through a reduction of radiation losses. :,... Variable Frequency Drive: Large energy savings can be achieved by changing the flow control on air handling machines such as large fans used on cement kilns. The increased fan pressure puts more load on the constant speed motor causing large energy loss. To avoid, the energy loss the best solution is to remove the dampers so as to eliminate all flow resistance and control the fan speed. A Variable Frequency drive (VFD) which controls the frequency of the power is connected to the motor. In this way the motor speed can be adjusted to match the desired fan speed and flow. The energy used is much less than using an output damper to control flow. Uniform Measurement and Verification (M&V) procedure does not exist. Conducive policy intervention existing in certain states does not exist in other states. For instance, in Rajasthan policy is framed in a manner that the policy assists companies in meeting their Renewable Purchase obligations (RPO) targets. As a result, it can be noted that the 75% capacity of Waste Heat Recover capacity (WHR) is installed in Rajasthan. There are other states like Madhya Pradesh (MP), Chhattisgarh and Andhra Pradesh (AP) with huge potential , but WHR process is not widespread in these states.