Cogeneration of Bagasse

Cogeneration of bagasse is one of the most attractive and successful energy projects that have already been demonstrated in many sugarcane producing countries such as Mauritius, Reunion Island, India and Brazil. Combined heat and power from sugarcane in the form of power generation offers renewable energy options that promote sustainable development, take advantage of domestic resources, increase profitability and competitiveness in the industry, and cost-effectively address climate mitigation and other environmental goals.

According to World Alliance for Decentralized Energy (WADE) report on Bagasse Cogeneration, bagasse-based cogeneration could deliver up to 25% of current power demand requirements in the world’s main cane producing countries. The overall potential share in the world’s major developing country producers exceeds 7%. There is abundant opportunity for the wider use of bagasse-based cogeneration in sugarcane-producing countries. It is especially great in the world’s main cane producing countries like Brazil, India, Thailand, Pakistan, Mexico, Cuba, Colombia, Philippines and Vietnam. Yet this potential remains by and large unexploited.

Using bagasse to generate power represents an opportunity to generate significant revenue through the sale of electricity and carbon credits. Additionally, cogeneration of heat and power allows sugar producers to meet their internal energy requirements and drastically reduce their operational costs, in many cases by as much as 25%. Burning bagasse also removes a waste product through its use as a feedstock for the electrical generators and steam turbines.

Most sugarcane mills around the globe have achieved energy self-sufficiency for the manufacture of raw sugar and can also generate a small amount of exportable electricity. However, using traditional equipment such as low-pressure boilers and counter-pressure turbo alternators, the level and reliability of electricity production is not sufficient to change the energy balance and attract interest for export to the electric power grid.

On the other hand, revamping the boiler house of sugar mills with high pressure boilers and condensing extraction steam turbine can substantially increase the level of exportable electricity. This experience has been witnessed in Mauritius, where, following major changes in the processing configurations, the exportable electricity from its sugar factory increased from around 30-40 kWh to around 100–140 kWh per ton cane crushed. In Brazil, the world’s largest cane producer, most of the sugar mills are upgrading their boiler configurations to 42 bars or even higher pressure of up to 67 bars.

Technology Options

The prime technology for sugar mill cogeneration is the conventional steam-Rankine cycle design for conversion of fuel into electricity. A combination of stored and fresh bagasse is usually fed to a specially designed furnace to generate steam in a boiler at typical pressures and temperatures of usually more than 40 bars and 440°C respectively. The high pressure steam is then expanded either in a back pressure or single extraction back pressure or single extraction condensing or double extraction cum condensing type turbo generator operating at similar inlet steam conditions.

Due to high pressure and temperature, as well as extraction and condensing modes of the turbine, higher quantum of power gets generated in the turbine–generator set, over and above the power required for sugar process, other by-products, and cogeneration plant auxiliaries. The excess power generated in the turbine generator set is then stepped up to extra high voltage of 66/110/220 kV, depending on the nearby substation configuration and fed into the nearby utility grid. As the sugar industry operates seasonally, the boilers are normally designed for multi-fuel operations, so as to utilize mill bagasse, procured Bagasse/biomass, coal and fossil fuel, so as to ensure year round operation of the power plant for export to the grid.

Latest Trends

Modern power plants use higher pressures, up to 87 bars or more. The higher pressure normally generates more power with the same quantity of Bagasse or biomass fuel. Thus, a higher pressure and temperature configuration is a key in increasing exportable surplus electricity.

In general, 67 bars pressure and 495°C temperature configurations for sugar mill cogeneration plants are well-established in many sugar mills in India. Extra high pressure at 87 bars and 510°C, configuration comparable to those in Mauritius, is the current trend and there are about several projects commissioned and operating in India and Brazil. The average increase of power export from 40 bars to 60 bars to 80 bars stages is usually in the range of 7-10%.

A promising alternative to steam turbines are gas turbines fuelled by gas produced by thermochemical conversion of biomass. The exhaust is used to raise steam in heat recovery systems used in any of the following ways: heating process needs in a cogeneration system, for injecting back into gas turbine to raise power output and efficiency in a steam-injected gas turbine cycle (STIG) or expanding through a steam turbine to boost power output and efficiency in a gas turbine/steam turbine combined cycle (GTCC). Gas turbines, unlike steam turbines, are characterized by lower unit capital costs at modest scale, and the most efficient cycles are considerably more efficient than comparably sized steam turbines.

Insights into Automatic Weather Monitoring Station

Weather variables such as wind speed and direction, air temperature, humidity and rainfall are important factors in determining the course of a wide range of events. For example, agriculture has always been heavily dependent on the weather and weather forecasts, both for its control on the quality and quantity of a harvest and its effect on the farmer’s ability to work the land or to graze his stock.

Water resources generally depend critically not just upon rainfall, but also other weather phenomenon that together drive plant growth, photosynthesis and evaporation. Just as pollen and seed dispersal in the atmosphere are driven almost entirely by the weather, so too is the direction and distance of travel of atmospheric pollution.

Weather monitoring is also important not just in defining present climate, but also for detecting climate change and providing the data to input into models which enable us to predict future changes in our environment.

Because of the wide variety of uses for the information, there are a large number of environmental variables which are of interest to different groups of people. These include solar radiation, wind speed, wind direction, barometric pressure, air temperature, humidity and net radiation.

The demand for these data, usually on an hourly or more frequent timescale, has increasingly been met by the development and widespread deployment of automatic weather stations (AWS’s) over the past 30 years or so.

Automatic Weather Station

EE-WMS-01, the automatic weather station developed by India-based Engineering and Environmental Solutions is a highly sophisticated monitoring & logging of intrinsic weather conditions like temperature, barometric pressure, wind direction, wind speed, wind chill and other optional parameters according to your requirements.

Automatic Weather Monitoring Station developed by Engineering and Environmental Solutions

Application areas include agriculture, hydrology, ecology and meteorology. For any sort of customized application, Engineering and Environmental Solutions can give assistance to select the best blend of sensors, data logger and accessories accordingly.

  • Field proven in severe weather conditions.
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Flexibility and Customization

The DL-W’s analog inputs can be fully customized. Each channel can have its own input type and recording parameters. Software gives the user control over reading frequency, thresholds and units, and provides recording options for average, min and max, plus specialized wind options ? including wind rose, gusts and wind averaging Users can add their own custom sensor types to the sensor library, exploiting the DL-W’s detailed configuration options.

The DL-W provides 4 input ranges down to microvolt resolution with adaptive auto?ranging, excellent analog accuracy, and configurable sensor excitation enabling it to support nearly all analog sensors. Calculations based on the measurements from several input channels can be recorded and displayed as additional virtual channels (calculated measurements).

For more information and business enquiries please visit www.enggenv.com or contact Mohammad Hamza on +91-9540990415 or email on enggenvsolution@gmail.com or salman@bioenergyconsult.com