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Waste Heat Recovery – Featured Industry – PEC Consulting Group

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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Alternative Fuels

Alternative Fuels

The use of alternative fuels, also known as “co-processing”, is the use of combustible waste materials as a source of energy in pyro-processing of cement manufacturing plants, lime plants, and in the calcining of other minerals.

Some forms of alternative fuels are:

    • Used tires.
    • Plastic waste (bags, bottles etc.).
    • Waste Oils.
    • Solvents.
    • Saw dust.
    • Paint.
    • Hazardous Wastes.
    • RDF (Refuse Derived Fuels).

Benefits

Conversion to alternative fuels benefits the economy of operation by lowering fuel costs. In some cases, a facility that uses alternative fuels receives economic compensation for waste elimination (e.g. use of Hazardous Wastes). In addition to energy recovery, there are considerable environmental/green benefits, such as the reduction of emissions and greenhouse gases into the atmosphere by not using natural non-renewable raw materials and fuels such as coal. In certain countries, these savings can be utilized for Carbon Trading credits.

However, because of their inherent characteristics, the implementation of alternative fuels present a challenge to use which, if not handled properly, may impact the manufacturing process, product quality, and environmental exposure.

What We Do

At PEC Consulting we provide innovative and thoughtful solutions to help the cement industry and lime industry implement co-processing at their plants and become more cost efficient, which improves their economic competitiveness.

An alternative fuels project will evaluate the characteristics of co-processing and recommend ways to handle and utilize fuels in the pyro-process in the most effective and secure way.

Our scope of work includes:

    • Studies for handling and firing Solid Waste Fuels.
    • Studies for handling and firing Liquid Waste Fuels.
    • Studies for handling and firing Hazardous Waste Fuels.
    • Conceptual studies to use whole or shredded tires.
    • Studies to use gas or petroleum coke (petcoke) as replacement fuel.
    • Alternative Fuels / Co-Processing Studies for Cement Plants.
    • Alternative Fuels / Co-Processing Studies for Lime Plants.

How can we help you? Get in touch with our team of experts.

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Waste Heat Recovery Systems

Waste Heat Recovery Systems

Waste Heat Recovery Systems (WHR) utilize the heat in industrial waste gases for the generation of electrical power. WHR Systems are common in cement and lime plants and other pyroprocess industries where Rotary Kilns are used and the price and reliability of grid power supply make the investment economically feasible.

In developing the concepts for the WHR system, the challenge lies in determining the optimum quantity of waste heat available for power generation and in integrating the WHR system with the cement process. PEC Consulting can assist the client to perform a Feasibility Study to assess the optimum size and configuration of the WHR system and the viability of the project. The study will provide recommendations for an efficient and economical system based on several factors such as the thermal capacity of exhaust gases, size and type of heat exchanger, and desired parameters of the cogeneration system operating conditions.

In some cogeneration systems, the exhaust gas from power generator sets using diesel oil or furnace oil is used as a source of heat for the WHR plant.

Benefits

    • Reduction of electrical power demand from the grid and consequently of the plant’s operating costs.
    • Reliable electrical power supply from waste gases from the kiln and cooler.
    • Reduction of the carbon footprint by conserving the use of fossil fuels and thus helping the environment.

What We Do

    • Assess the realistic quantity of heat that can be recovered taking into account variations in the drying requirements of raw materials and fuel throughout the year. This analysis results in optimum sizing of the WHR system.
    • Determine the energy recovery process to be utilized: The steam Rankine cycle uses water as the thermodynamic medium and is commonly used for generating power from high temperature sources. Depending on the temperature and other situational factors, some plants use the Organic Rankine cycle for generating power, using an organic compound as the thermodynamic medium.
    • Optimize the layout of the boilers and power generation system considering plant footprint space constraints.
    • Provide an effective integration of the WHR equipment with the existing cement plant or industrial facility.
    • Provide our clients with an assessment of the power potential, a financial analysis with capital and operating cost estimates, and an economic analysis to assess the viability of the project.
    • Technical Feasibility Studies of WHR Systems for Cement Plants.
    • Technical Feasibility Studies of WHR Systems for Lime Plants.

Learn more about WHR; click on the following publication:

Waste Heat Recovery for Power Generation

To download a list or Energy Efficiency/Process Studies, including WHR projects, please click here.

How can we help you? Get in touch with our team of experts.

CONTACT US
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