Principles of the Unit Pirotex Operation
Main parts of the line of chemical synthesis of pyrogas in the unit Pirotex designed for recycling and utilization of rubber- and polymer-containing wastes are wet scrubber, coagulation wet drops separator and centrifugal separator.
Main parts of the line Pirotex:
Heated up to 260-560 degrees Celsius pyrogas goes from the crucible filled with rubber through gas-pipe, passes through the gates into the wet scrubber, where under the effect of cooling reagent wetting it condenses partially and cools down. Then, going through the Venturi pipe connected with it by counterflow packed adsorber, oil component of pyrogas completely cools down and condenses to a liquid synthetic fuel. Centrifugal separator is used for pyrogas dehydration. After this the gas is used in full to sustain the pyrolysis process.
This system allows us to extract liquid component from pyrogas without loss.
During the pyrolysis process under the external heat influence in different time intervals different quantities (volumes) of pyrogas are produced in the crucible filled with rubber (car tires); this gas is pumped out by gas fan from the reaction zone. Pressure sensitive system is used to control pressure reducing in the crucible; this system is connected with the frequency controller that sets appropriate fan rotation speed.
As pyrogases are removed from the reaction zone very quickly, maximum amount of liquid fraction – up to 60 % of the whole volume of the loaded feedstock – can be produced. Presence of pyrolysis liquid vapors in high-temperature zone for a long time causes secondary cracking and vapors decompose into non-condensable under normal conditions gases. Additional heating energy is required for secondary cracking, and decomposition of pyrolysis liquid vapors into gases causes reduction of pyrolysis liquid output.
Initially, indirect rubber heating in the crucible is performed by means of pyrolysis fuel combustion in specially set and adjusted for its specific composition burners. High percentage of heavy fractions in the product and great amount of chemically bound “pyrolysis water” didn't allow us to obtain stable flame in different burners of such trademarks as BALTUR, BENTONE, etc. for a long time. At the moment this problem is successfully solved, and specially designed system for removal of exhaust gases from fuel combustion in the burners allows us to operate them almost without production of smoke and smell. This factor is very important for saving of ecological balance. The burners are identical to american burners in all respects, but these are almost three times cheaper and do not require specific maintenance that allows us to keep the price for the equipment in a competitive market segment.
The unit Pirotex is operated almost 24 hours a day in operating mode, the pyrolysis process of one portion of feedstock (0.3 – 1.5 tons) lasts for 5-6 hours. Used for pyrolysis acceleration catalyst allows us to recycle nearly 2.2 times more rubber within the certain time period. The catalyst is continuously renewable in the process and requires no additional costs. The rubber preheating system allows us to save up to 18 – 20 % of the fuel in the initial stage.
Feedstock cooling system after the pyrolysis process completion. Produced after pyrolysis of rubber in the crucible at the end of reaction the carbon residue has a temperature of 400 – 550 degrees and under normal conditions it requires 12 – 14 hours to cool it down before the opening of the crucible. The cooling system of carbon residue by superheated steam is used. Steam comes from the steam generator through the pipeline into the crucible and within 30 - 80 minutes affects the carbon residue and metal cord.
After cooling to 120 – 140 degrees Celsius derived product can be unloaded and separated, but firstly big pieces of metal wire should be separated by means of the vibrating sieve. After the vibrating sieve the fraction carbon residue goes through the belt conveyors with integrated magnetic separator, the residue is separated from metal inclusions completely and is ready as a semi-product for further processing.
Hydraulic tipping device is designed for carbon residue and metal cord unloading from the crucible to the vibrating sieve that allows to minimize manual labor.
Experience has shown that initially it is required to spend from 15 to 25 % of liquid fuel produced by the unit to come to an operating mode of mechanical rubber goods pyrolysis. Accordingly, the loading of 500 kg of rubber into the crucible allows production of up to 300 liters of pyrolysis liquid fuel, 75 liters of this fuel is required for the feedstock preheating. After the change of liquid fuel to gas (pyrolysis gas) the reaction lasts for another 4.5 hours.
Then the used crucible with carbon residue and metal cord is replaced by the preheated up to 80 - 120 degrees Celsius crucible filled with rubber and produced during operation of the burners exhaust gases, which allows to spend 20 percent less fuel for start of the reaction than for the start-up of the unit. Heat-insulated by basalt and lined with fire bricks pyrolysis furnace designed for isolation and condensation of produced by the oil-gas burners heat allows to economize on heat-carrier due to engineering solution as well.
The unit has almost no atmospheric emissions. This fact allows us to state that the use of the unit Pirotex can be recommended for the regions with strict environmental standards.
You can visit the site of the group of companies Zhelezno and learn more about operation of the equipment Pirotex designed for rubber- and polymer-containing waste recycling and utilization, as well as about its capacity and engineering solutions. In case you want to do so, please, fill in the Registration form for Visiting of the Equipment Demonstration.