Quality Control

RAW MATERIAL:-

Only wastes of PP/PE/LDPE & HDPE should be used
If only Pyro gas is the requirement then PET can be used. PET will produce majorly pyro gas a a very small percentage of oil.
Maximum moisture permissible - 10% maximum impurities ( sand, fillers others) - 5%.
If mixed waste plastics are used then it is absolutely essential that the mixed plastics are analysed for Calorific value & ash.
If calorific value is above 8000 KCAL /kg and ash max. 5% then the quality of mixed plastics as raw material for pyrolysis acceptable else not, below 8000KCL/kg material if processed will not be commercially viable.
.Lower calorific value mixed waste if used will result in lower yield of of pyro oil.
High fillers and other solid impurities and ash will result in lower yield of oil and higher percentage of carbon mixed with the fillers /sand .
Sand and fillers in the carbon will make the carbon from the plant commercially unsaleable and therefore only fit for landfill.
PET can also be used as a raw material but with PET only pyro gas will be produced little or no pyrolysis oil will be produced.
In case while processing mixed waste plastics it is found that adequate gas is not produced as a result of which external source of heat using fuel oil is used the feed of waste plastics should include at least 10 t-20% of PET waste wrappers to ensure the energy for pyrolysis is self sustaining.

PLASTIC PYRO OIL:-

Yield of Pyro Oil will largely depend on the type of plastic and presence/absence of impurities as well as moisture present in it. For a good yield it is necessary that the mixed plastics should have a minimum calorific value of 8000 KCAL/kg and max. ash content on incineration 5%.Any variation upward or downward will proportionally increase or decrease the yield.

Typical composition of Plastic pyrolysis oil is:-

Click on the link below to view certificate of analysis:-

NOTE:-

The ash content of 41.4% signifies presence of high percentage of fillers and other impurities.
The ash analysis confirms presence of 68 % CaO i.e. calcium carbonate filler.
Particle size is good and further grinding may not be necessary.
Commercially, the product is of no value unless the carbon is separated from the calcium carbonate filler through electro static seperators.
Therefore, this proves the fact that quality of raw material controls the quality and yield of products be it oil or carbon residue.
The analysis confirms that If pure plastics without fillers are used as raw material the carbon residue from plant would be 95% pure and categorized as saleable commodity.

END PRODUCT:-

PYRO OIL:- The end product is a mixture of hydrocarbons which conforms to Furnace Oil and Light Diesel Oil specifications and therefore can be used as a fuel, or fractionated in a rectification column to yield household chemicals or other chemicals (petroleum, wax, paraffin, solvents, and thinners.

RESIDUAL CARBON:- Test results of the results above shows that due to presence of high fillers in the plastic fed to the plant the residual carbon has an ash content of 41% against expected max. 5%. And carbon 29% The product as such is of no commercial value. However using a Electro static separator it could be possible to separate the carbon and the calcium carbonate in the residue.

How economical this process would be needs to be examined.

Detailed laboratory test of the end product hydrocarbon oil gave results as shown above:-

The product does not contain Sulphur or chloride; thus it is valuable for various industrial sectors.
It is composed of hydrocarbons with relatively high number of methyl group (-CH2).
It does not contain significant volume of aromatic components (benzene is not identifiable); It does not contain any component that would be composed of carbonyl and alcohol containing groups; no presence of double or triple bonds.
Fractions of hydrocarbons of different boiling points can be separated with rectification. Rectifier unit is available to the equipment as an option.

Assuming that the total output represents 100 % liquid Hydrocarbon/ fuel oil the recommended percentages of fractions that could be recovered on fractional distillation would be the following:

15%-20 % temperature range 300°C to 360° C (paraffin wax);
60%-70% temperature range 220°C to 280° C (light fuel oil – Diesel );
15% to 20% temperature range 105°C to 140° C (thinner used in paint industry).

Thermolysis/Pyrolysis Oil has a boiling range falling between the boiling range of diesel and Petrol as depicted in Figure-3 below. This signifies that rectification of plastic pyrolysis oil would yield a certain fraction of petrol and wax and a higher fraction of Diesel.

The product does not contain Sulphur or chloride; thus it is valuable for various industrial sectors and a good substitute to fossil fuels.
Plastic /Rubber to Oil plants operate commercially in Germany, United Kingdom, Japan and the United States of America. Government provides a high level of subsidy to such plants in these countries.
Such environmentally plants qualify for government subsidy and many countries worldwide have extended liberal subsidies.
If government subsidies are made available to plastic & tire plants in India also then many Plastic/tire to Fuel Oil plants will come into operation thereby usefully processing the hazardous wastes which presently are by force sent to landfill.

Laboratory:-

The presence of a quality control laboratory in the plant premises cannot be over emphasized.

The laboratory should be equipped to analyse the following in raw materials and finished products for efficient operation.:-

Moisture content of raw material and pyro oil.
Calorific Value.
Ash Content.
Pilot Plant for assessing ideal operating temperature Oil quantity, residual carbon and by difference pyro gas produced ,oil quality and residual carbon content. (e) effluent water analysis (f.) Flue gas analysis.