Chicken Manure to Megawatts

Güres Group is turning a liability into an asset via clean energy technology.
By Ilaria Peretti | September 09, 2019

Güres Group, the largest integrated egg plant in Turkey, has an annual production of about 1 billion eggs. The company was founded by Ahmet Remzi Güres in 1963 with only 600 hens, and today is the country’s largest, fully integrated egg production plant under a single roof, hosting 4 million laying hens in 35 hen houses with varying capacities of up to 155,000.

Its combined structure hosts an egg production plant, feed factory, egg tray factory, broody hen, pullet and productions plants, fertilizer productions plants, and a technology factory, totaling 7 million square feet (SF), with a closed area of 2.5 million SF. 

After several years of R&D activities undertaken by Güres to turn a major environmental issue into clean energy, the company signed an order with Italy-headed Organic Rankine Cycle (ORC) turbo generator manufacturer Turboden S.p.A., a group company of Mitsubishi Heavy Industries, for the supply of a unit to be installed at the company’s main production site in Manisa, Turkey.

The 2.3 MWe ORC at Güres,  which began operations in 2018, converts the heat from the combustion of chicken litter into hot water that is employed in tailor-made dryers specifically designed by Güres to dry the chicken litter prior combustion, and power that is sold to the grid at a feed-in tariff (FIT) rate specific for bioenergy. About 300 metric tons of chicken litter per day are sourced entirely from Güres’ egg production.

Liability to Asset
The main components of Turboden’s ORC units are produced locally by the company’s Turkish subsidiary Turboden Turkey A.Ş. This is beneficial to Güres—a result of using locally fabricated components, Güres qualifies for a higher feed-in tariff for electricity sales, $153 per megawatt-hour (MWh), rather than $133 per MWh.

Gures Group has been in the egg-production business for longer than 50 years. Extensive knowledge, knowhow and experience have been acquired through the years, not only regarding egg production, but also manure handling. The first and the most important step in developing a project to manage and utilize the manure for clean energy was to define what type of system was the most convenient and feasible. To begin, thorough research, literature review and investigation was done on both commercial and noncommercial systems around the world, including gasification, pyrolysis, biogas, combustion and fermentation systems. After the advantages and disadvantages of all those systems were compared, combustion was selected. Although gasification and pyrolysis are very efficient methods, the processes do not run stable with poultry manure. Biogas-to-energy is a process that’s very easy to operate, but the manure requires additional mass—such as diary manure or sludge—to increase its low carbon-to-nitrogen ratio for efficient biogas production. This also results in the need to handle and dispose of a large volume of mud after the biogas production complete.

Combustion of manure is very challenging from a technical perspective. Due to its high amount of ash, alkaline, chlorine, tar and wet content, the combustion system must be designed and developed very carefully, considering all of those aspects. If not properly done, the system can fail within a short period of time due to high-temperature corrosion, thermal efficiency may be very low, emissions may be over regulatory limits, or the system may require frequent maintenance due to ash agglomeration. The system may also end up needing extra fuel such as gasoline to maintain the required temperature inside the boiler. In the past five years, we have performed R&D work to solve the aforementioned issues, building a prototype two and a half years ago to perform functional and performance tests.

As a result of testing, it was learned that the manure, especially layer manure, requires pre-drying for optimum combustion efficiency, so Turboden developed a new generation manure dryer that can be run with a low-temperature heat source, such as 70 degree Celsius (C)hot water. This dryer can dry any manure from 75 percent wet content down to 25 percent wet content in 24 hours by only using this low-temperature heat source.

Besides ease of operation, safety and modularity, a significant reason Güres chose an ORC system is that it is able to run with a heat source less than 350 degrees C, with more than 20 percent electricity conversion efficiency. Its fluidized bed combustion boiler heats the thermal oil up to 300 degrees C, and it is then delivered to the ORC’s evaporator, returning to the boiler at 260 degrees C. Therefore, the metal surface temperature in their heaters can be kept less than 350 degrees C. This is very important to high-temperature corrosion on the metal surfaces, or the system is susceptible to failure in just a few years.

Carrying out its activities and production compatible with environment legislation and internationally accepted environment management systems—including production of most of its energy demand via solar—Güres Group’s most important mission is to leave a livable and clean environment to future generations. The system installed at the egg plant is one of 10 that Turboden has in various stages of development in Turkey, with an overall power capacity of 35.7 MWe. The company has nine installations in Canada (36 MW) and 3 in the U.S. (21 MW).

Author: Ilaria Peretti
Sales Area Manager, Turboden