Customer Background and Thermax Partnership: Since 2009, Thermax has been a trusted partner to a reputed cement manufacturer in Karnataka for its 6000 TPD unit, providing Operation and Maintenance (O&M) services for the 2×25 MW captive power plant. The plant has two AFBC (Atmospheric Fluidised Bed Combustion) boilers of 110 TPH capacity each generating steam at 88 ata, 520ºC.
Problem: The customer had a challenging requirement of optimising the reuse of their hazardous waste viz. fly ash by reducing its carbon content. As a standard practice, the fly ash generated from the boiler is utilised in the cement mill. However, only the fly ash with a Loss of Ignition (LOI- the amount of carbon left in fly ash which has a potential heat value) less than 8% can be utilised, and the rest needs to be disposed of which has several constraints, considering its hazardous nature.
Further, a high level of carbon content in ash due to Loss of Ignition is undesirable for power plants as it leads to boiler efficiency loss and higher specific fuel consumption.
Approach: To counter this situation, the team conducted an analytical study on factors affecting the increase in LOI. It was identified that LOI was increasing due to insufficient burning of fuel in the secondary part of the boiler. Change in fuel properties also had a significant contribution to the problem.
Solution: Thermax recommended the installation of a Cinder Recovery System to counter the factors leading to a higher LOI in the boiler. This system utilises unburnt carbon in the fly ash by re-firing it in the boiler, which is conveyed through the primary air.
The team made a detailed proposal with a cost benefit analysis of the Cinder Recovery System to the customer. As the system was designed by Thermax’s in-house engineering and commissioning team, the customer was relieved of any risks associated with its performance. The team also modified the intermediate storage of ash, which was resulting in a drop in the temperature of ash.
This modification, along with the installation of the Cinder Recovery System resulted in a reduction of the LOI from 15-17% to 6-8%, while eliminating the need for disposing of hazardous waste.
- Reduction of LOI to 6-8% benefited the customer in many ways – they were able to utilise the fly ash in cement mill and saved on the cost of fly ash disposal
- Boiler efficiency was improved by 0.5%
- Heat rate reduced by 45-50 kcal/kWh
- Fuel saving of approximately 2,250 tons/year was achieved
- Overall fuel saving resulted in a reduction of carbon footprint by 7,321 tCO2e/year
About Tourah Cement
The Tourah Portland cement Plant, Egypt’s first cement company, was established in 1927. It is owned by Suez Cement company (66.12%). The company consists of two plants located in an area of 10,000,000 m2 in Tourah district with 9 production lines.
The Changing Business Scenario
Driver of the Change: Emission Standards
As global awareness and concerns grew about the Air Pollution and its hazards, Egypt also decided to upgrade the emission standards that a cement plant must meet in order to ensure a cleaner and healthier environment.
As per the changes in the law, any cement company in Egypt must meet the new emission standards of SPM < 20 Mg/NM3 from earlier acceptable limits of SPM< 100 Mg/NM3 resulting into a complete change in the business scenario for Tourah Cement.
Affected Applications, Utilities and Challenges
|Raw Mill x 2
||ESP x 2
|Alkali By Pass & Gas Cooling Tower
APC: Air Pollution Control Equipment
ESP: Electrostatic Precipitator
GBF: Gravel Bed Filter
Challenges Associated with Rehabilitation
1. Efficiently meet the expected new emission standards.
2. Minimize capex and downtime of the plant and without disturbing the other operations much.
3. Modifications and additions within the little space available posing as a significant constraint
Solution Offered by Thermax
Thermax studied the requirements of the customer and associated challenges. Based on its years of experience, Thermax Retrofit and Revamp Design team came out with a solution to be executed within 45 days planned shutdown for all the three applications. In order to reduce the Capex, Thermax used its engineering skills so that the existing structures, casing, hoppers etc can be utilized to maximum in the new solution.
Raw Mills (Both) – ESP for replaced with Pulse Jet Bag Filter
Existing Casing was repaired and partition was created to accommodate the new 2 chamber Bag House.
Existing building was strengthened and used.
Clinker Cooler – Gravel Bed Filter replaced with Heat Exchanger & Pulse Jet Bag Filter
Heat Exchanger was provided for Clinker Cooler Gases prior to entering the Bag Filter Chamber.
The Bag filter with six compartments was constructed on the structures of the existing Gravel Bed Filter New Ducting connecting to old discharge system was only used.
Alkali By-Pass & GCT -ESP replaced with Pulse Jet Bag Filter
Existing ESP Support structures & Hoppers were used to construct the New Bag Filter The existing GCT was upgraded to handle dual fuel.
Final Process Parameters
||Inlet Dust Load(gm/NM3)
||Outlet Emission Achieved(mg/NM3)
|Raw Mill x 2
||Pulse Jet Bag Filter
||Pulse Jet Bag Filter
|Alkali By Pass & Gas Cooling Tower
||Pulse Jet Bag Filter
1. Execution of project covering all the 3 applications completed in the planned shutdown of only 45 days.
2. Equipment handed over after commissioning in just 15 days.
3. CAPEX reduced as per customers expectations by utilizing existing structures to maximum possible.
Project in Pictures
Alkali By Pass & Gas Cooling Tower
Customer Background and Thermax Partnership: At one of the leading cement manufacturer’s unit at Rajasthan, Thermax is providing Operation and Maintenance (O&M) services for its captive power plant of capacity 21 MW and WHR power plant of capacity 13 MW since 2008. The plant has an 89 TPH AFBC (Atmospheric Fluidised Bed Combustion) boiler and 5 WHR (Waste Heat Recovery) boilers of 72 TPH combined (both boilers are made by Thermax).
Project Background: Auxiliary power consumption is one of the key performance indicators for a power plant. As a part of the customer’s ‘energy efficiency’ drive, the Thermax team took a target of reducing the auxiliary power consumption to enhance the net power generation.
Approach: Thermax team conducted a detailed analysis of the equipment data using advanced proprietary tools. They also organised workshops to drill down on the key parameters driving higher auxiliary power consumption.
Specific teams were formed to study:
- Power consumption pattern equipment-wise and area wise
- All possible ideas for improvement
Solution: Thermax team presented a comprehensive plan to the customer for reducing auxiliary power consumption for captive and WHR power plants. The plan included actions with and without capital investments. Over the span of the last two years, various opex initiatives such as ‘auto control logics for flow optimisation’ and capex initiatives such as ‘VFD installation’ were implemented. The customer also agreed for capex investment after being apprised by the Thermax team about the long term savings and lifecycle cost reduction.
- For the captive power plant, 72.4 lakhs of unit cost saved through capex and 18.8 lakhs unit cost saved through opex
- For WHR unit 8.7 lakhs of unit cost saved through capex and 1.9 lakhs unit cost saved through opex
- The total auxiliary power consumption was reduced by 1% for captive power plant and 2.2% for WHR unit
- Carbon footprints reduced by 1,200 tCO2e/year for captive unit and 1,300 tCO2e/year for WHR unit
Thermax SPX Energy Technologies Ltd, the joint venture, bagged an order for seven air cooled steam condensers from the cement conglomerate, Nuvoco Vistas Corporation (formerly Lafarge). The condensers will be installed at cement plants in Rajasthan, Chattisgarh and Jharkhand – three for waste heat recovery systems (WHRS) and four for captive power plants (CPP).
Air Cooled Condensers (ACCs) utilise ambient air for cooling – an effective alternative to the wet cooling towers used earlier by captive power plants in the cement industry. ACCs are environment friendly in many ways. They save water in water-scarce areas since no water is required for cooling. They reduce the use of chemicals for water treatment, bring down corrosion in auxiliaries, and eliminate plume, blowdown and treatment of associated discharge water.
The scope of the project includes design, engineering, manufacturing, construction and commissioning at site as well as performance guarantee testing before handing over. The commissioning of the WHRS and CPP units will take place over the next 12 months. This is the JV’s largest order from a single customer, bagged against stiff competition.
The Power division of Thermax recently commissioned a 40 MW coal-based captive power plant for Sharjah Cement Factory, a leading cement and clinker manufacturer in the UAE.
This is the first full-fledged EPC project to be executed by the division in the region. It comprises two CFBC boilers of 90 TPH capacity each that are capable of firing multiple varieties of coal along with a first-of-a-kind 30% wood chip firing.
The project scope involved the supply and commissioning of Thermax DM plant, bag filters and dust extraction system along with other Balance of Plant equipment. The plant was conceptualised and synchronised within a record time of 18 months. Commencing 25th March, the plant is operating on stable load and generating power till date.
Cement plants in India are aiming for higher efficiency and profitability in their operations. One of the ways to achieve this is to use waste heat from operations for power generation. A pioneer in waste heat recovery based power plants, Thermax has begun work on a captive power plant at Maihar, Madhya Pradesh for a cement manufacturer, a group company of Birla Corporation Limited. The Rs. 98 crore project will harness waste heat of the cement plant to generate 12.25 MW power. The scope of the project includes boilers, turbine, air cool condenser, ducting, civil, electrical control and instrumentation, and other accessories. For this EPC project, Thermax will install a space-saving vertical preheater boiler. The project is expected to be commissioned by the end of 2018.