Feasibility study on waste oil disposal in cement kilns for Sri Lanka

Abstract

1. Main Objective

To study the feasibility of disposing the waste oil in the existing Puttalam Cement Kilns for Sri Lanka. To achieve this objective, the current situation in terms of technologies (manufacturing, fuel firing, process control, dust emission equipment and performance, etc.) of Puttalam Cement and the financial viability was evaluated. 2. Introduction Disposing of waste oil in Cement Kilns will give three fold benefits: getting rid of waste oil, almost without any residue, complete energy recovery which contribute to the economy of a country and special disposal facilities are not needed as an existing facility is utilised

High flame temperatures and the nature of the product make cement kilns attractive for the destruction of a variety of hazardous organic materials. With proper management, kilns constitute a much less costly alternative to dedicated waste incinerators. Tests by USEPA and others have demonstrated that destruction of organic compounds including, PCBs and organochlorine and organophosphorus pesticides, equals or surpasses that achieved in hazardous waste incinerators tl1at operate at l wer temperatures. Many toxic metallic compounds can also be burned in cement kilns in quantities that are small enough not to adversely affect product quality or safety, since they are bonded to the clinker and become part of the product. 3. Waste Oil It refers to lubricating oils, hydraulic, transmission & heat transfer fluids and insulants that have gone tl1rough their intended use cycle and must be either disposed of or treated and re-used. In this thesis, waste oil from automotive transport sector is only considered. Other transport (aviation and maritime) sector and spent industrial oils are not included here as waste oil since these oils are contaminated with unknown pollutants.

4. Waste Oil Generation and Properties in Sri lanka

A pilot survey was carried out to estimate the waste oil generation and centrally collectable amount. According to tl1e survey results, in 1999 around 24,000 - 27,000 ton waste oil was generated by automotive transport sector in Sri Lanka. However, tl1e known collectable amount is 4,500 (about 18% of the generated amount) while the estimated amount is around 17,400 ton per year in 1999 as given in Table 23. With time, awareness, incentives, and enforcement of regulation, the estimated amount can be collected.

The laboratory test results show that our waste oil property is within the literature values in terms of physical property and tl1e contaminants such as heavy metals. However, it is interesting to note tl1at tl1e ASTM distillation curve of tl1e waste oil distillate resembles kerosene oil and the quantity distilled also only 63%. This shows that the best option in World of waste oil disposal by rerefining back to lube base may not be possible in Sri Lanka and therefore, tl1e best option for our waste oil is using as alternate fuel which is well supported by tl1e high calorific test results (> 44,000 kJ/kg). However, with the limited number of tests it is difficult to come to a firm conclusion. This is only an indication.

5. Puttalam Cement

Cement is manufactured by grinding an artificial rock called "clinker" very finely (to a few microns) mixing with a small amount of gypsum (approximately 4%). Clinker is produced by heating limestone (77%) and some other ingredients (23%) to around 1450°C in a kiln. At Puttalam Cement Factory, there are two identical rotary kilns. The length of a kiln is 54 m. The burner of the kilns were change recently by Rotaflam kiln burner which has an additional jacket tube for a waste oil gun.

A complete actual material balance could not be done with the current on line measured and recorded data at Puttalam Cement. Therefore, some assumptions were made using the equipment specifications and international norms 1n domg the material balance. The average amount.......x·ffffff_·raw materials used for one