PNX method

Process description

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sewage sludge task

The sewage sludge is fed in via two walking floor containers, which are used for entry into the system. The sewage sludge is transported into the plant by means of a screw conveyor.

 

sewage sludge hydrolysis

Mixing the sewage sludge with a basic digestion agent results in hydrolysis, in which organic substances are broken down and form water-soluble salts.

​sewage sludge dewatering

Water and ammonia are released in the form of vapors through multi-stage vacuum evaporation. Ammonia is removed in the form of ammonium sulphate, which is one of the products obtained, by washing with sulfuric acid.

 

Autothermal reforming 

In an autothermal reformer designed as a rotary tube, the remaining water is first converted into combustible gas at temperatures of 700 - 800 °C in the form of water vapor and then organic salts. 

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Gas cleaning and recycling

The resulting process gas is cleaned using basic scrubbing, iron hydroxide solution and activated carbon filtration and then converted into electricity and heat in a CHP..

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Recovery of pulping chemicals

The powder discharged from the rotary tube is eluted with water, resulting in an approximately 50 M% solution. The inorganic, undissolved components are separated by means of a centrifuge. Phosphorus is removed from the remaining solution and the remaining solution is fed back into the process.

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