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State of the Art in Blended Cements 

In the manufacturing of Blended Cements, expensive clinker is substituted with other cementitious materials such as granulated slag, fly ash, or other naturally occurring pozzolanic materials resulting in different types of Blended Cements with unique properties.

The advantages of Blended Cements over Ordinary Portland Cement (OPC) are:

  1. Higher cement output for the same clinker production.
  2. Lower production costs since the substitute materials are cheaper than clinker.
  3. Superior properties for certain applications because of the strength, lower hydration heat, and high performance of Blended Cements.
  4. Environmentally-friendly due to fuel savings and the reduction of CO2 emission on the basis of per kg product.

Careful attention to the following guidelines should be given when making reliable Blended Cements:

  1. Evaluation of the availability and economics of the additive to be used
  2. The specific application of the Blended Cement
  3. Percentage addition of the substitute materials d. Water demand
  4. Fineness of the product – needs to be ground finer than OPC
  5. Grinding system capacity and system configuration
  6. Drying requirement since generally the substitute materials contain higher moisture
  7. Inter-grinding or Inter-blending and separate storage for the product
  8. Strength development curve
  9. Heat development during hardening
  10. Market acceptance of the proposed product

In addition to the use of hydraulically active components such as granulated slag, pozzolana or fly ash, certain inert materials such as limestone could be added. While this addition does not contribute to the cement strength, it acts as a filler and may contribute to the workability of the cement paste. It is necessary to evaluate the quality of the limestone to make sure that the overall quality of the cement is not affected.

PEC Consulting Group has assisted cement companies with the evaluation of their raw materials and their existing systems and provided them with basic and conceptual engineering for the production of Blended Cements. We can coordinate with reputed testing facilities to evaluate different materials to be blended and recommend optimum parameters.

Sample Scopes of Work include:

  • Feasibility and Technical Studies for Greenfield grinding plants
  • Feasibility and Technical Studies for developing the optimum system for manufacture of Blended Cements
  • Investigation of potential Blend Materials in coordination with laboratories and evaluating the properties of Blended Cements
  • Feasibility studies for converting OPC grinding systems to manufacture Blended Cements
  • Equipment Selection. Flow sheets, layouts, equipment lists and basic designs. Basic equipment specifications. Technology comparisons of major process equipment tenders
  • Capital cost and operating cost estimates of the project
  • Logistics
  • Economic viability analysis of the project

A Feasibility Study is the foundation for good project development and it is an absolute necessity for successful investments. By delivering a well prepared and thorough study, PEC Consulting helps its clients achieve their desired goals and maintain a competitive edge.

Main feature contributor: Narayana “Jay” Jayaraman

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Waste Heat Recovery for Power Generation

Hot process gases that are vented to the atmosphere by a Process Plant represent a potential for the generation of electric power. The installation of a Waste Heat Recovery (WHR) System is a “green” option that must be considered.

Typical-WHR-system

The Waste Heat Recovery (WHR) System consists of a steam generation unit and a power generation unit. The steam generation unit is a set of boilers placed in the path of the waste gases. The heat in the gases, sometimes supplemented by additional heat in the co- generation process, is used for generating steam. The steam can be used for other process requirements within the industrial plant, or used for driving a turbine that is connected to the generator. The generated power can either be used for running plant equipment or fed back to the power grid.

The recovered waste heat represents “green energy” since it is a direct savings in the use of fossil fuels with the consequent reduction of carbon dioxide emissions. Furthermore, cooling of the process gases is done without wasting scarce water or diluting with ambient air that would increase the energy consumption of the fans.

Several challenges exist, such as sticky and abrasive dust in the gas, or corrosive vapors such as SO2. The boiler must be custom-designed carefully to handle the specific characteristics of the off-gases. In special cases, like when there is a low gas temperature, an Organic Rankine cycle can be chosen instead of the steam cycle. The recovered waste heat represents “green energy” since it is a direct savings in the use of fossil fuels with the consequent reduction of carbon dioxide emissions. Furthermore, cooling of the process gases is done without wasting scarce water or diluting with ambient air that would increase the energy consumption of the fans.

waste-heat-recovery-India

PEC Consulting’s feasibility studies evaluate the characteristics of the process plant’s off-gases and assess the quantity of heat that can be usefully recovered. PEC Consulting will evaluate space limitations and find a solution to place the boilers and power generation system and integrate new equipment with the existing. PEC Consulting’s feasibility studies provide the client with an assessment of the power potential, a financial analysis with capital and operating cost estimates, and a layout to integrate the Waste Heat Recovery System with the existing process plant.

Waste Heat Recovery (WHR) Systems help process industries to become part of the green revolution by conserving natural resources. In addition to providing a reliable electrical supply, the reduction of the carbon footprint helps the environment. A co-generation plant is also a great benefit when the power grid supplying the plant is unreliable or when the plant is subject to interruptible power.

PEC Consulting can help the process industries with the realization of this noble and profitable goal.

 

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The Importance of Lime

Lime is one of the oldest and most important chemical products. Today it is equally significant to the economy of industrial processes. It is extensively used in mining of raw metal ores. Other industries utilize lime in their processes to remove or neutralize hazardous emissions. Its use brings well-known efficiencies and solutions that benefit the mining of raw metal ores and protect the environment.

featured-industry-lime

Lime is used in the production of steel in basic oxygen furnaces. In non-ferrous metallurgy, lime is used in copper, gold, and silver recovery. Lime is used to process alumina and magnesia, and to recover nickel by precipitation. Tailings that result from the recovery of precious metals, such as gold and silver, are treated with lime for environmental remediation purposes. It is used for softening municipal and plant process water and sewage treatment. In power plants and industrial plants, lime is injected into the flue gas to remove acidic gases. Hydrated lime may be used to control sulfur trioxide emissions at utility power plants. Lime is used by the pulp and paper industry and the chemical industry; it is used in sugar refining, in road paving, and in construction. Dead-burned dolomite, also called refractory lime, is the primary form of lime used in refractories.

LIME INDUSTRY– PEC Consulting Group’s Active Participation

PEC Consulting Group has provided technical assistance to industries and processing facilities that benefit the most from the use of lime. In doing so, we have actively helped industries meet the ever increasing demand for the production of quality lime. Sample Scopes of Work include:

  • Feasibility and Technical Studies for Greenfield lime production facilities
  • Feasibility and Technical Studies for capacity increase of existing plants
  • Investigation of potential raw material deposits such as sea shells, travertine, or limestone to be used as a source for quick lime
  • Geological exploration, core drilling programs, and testing for raw material physical and chemical properties
  • Mining Plans
  • Conceptual design of the mine and the plant
  • Equipment Selection. Flow sheets, layouts, equipment lists and basic designs.  Basic equipment specifications. Technology comparisons of major process equipment tenders submitted by equipment OEMs
  • Capital cost and operating cost estimates of the project
  • Logistics for supplying the mine facilities
  • Economic viability analysis of the project

A study forms the foundation for future development and it is an absolute necessity for successfully carrying a project to its completion. By delivering a well prepared and thorough study, PEC Consulting Group helps its clients achieve their desired goals and competitive edge. The efficient extraction of minerals and ores and how lime plays an important part in these processes is our specialty and expertise.

 

 

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