12.0 Predicted Environmental - Impact & Mitigation measures

Transcription

1 12.0 Predicted Environmental - Impact & Mitigation measures 12.1 The Assessment of the Impact on Environment by The High Vacuum Atomic Molecular Distillation Process: There are Positive impacts of the process, being acid free process, however some Negative impacts are identified with in-plant process and mitigation measures are part of the in-plant process itself, as described hereunder: The process proposed by M/s. Al-Abdulla Petroleum Co. Ltd., Mauritius, adopts a technology wherein greatest care is taken regarding the release of any hazardous constituents of the waste, neither released to soil, water or air. The basic technology involved is pre-treating the waste lube oil or industrial oils with natural polymers under vacuum to flocculate the carbon and separate it along with metals substantially. (This is one source of solid waste, diesel and water present in the waste oil, is the liquid waste.) The resultant oil is passed through the various stages of high vacuum molecular distillation plant at progressively higher and higher temperatures and vacuums to get different fractions of lube base oil. The distilled product is clay treated under vacuum to get good quality base oil with very low metals content, equivalent to virgin base oil. The bleaching results in the solid waste. Hence pre-treatment and final bleaching results in the solid waste. All vacuum pump exhausts are passed through the burner of the boiler and thus no hydrocarbon vapours escape /released to air Air Pollution Control in the Process The vacuum pumps (oil sealed) have the exhausts oil mists as well as the trace amounts of oil vapours from the distillation plant are led to the boiler for burning. The estimated quantities of flue gases are 800 cubic meters per hour. With low sulphur, low ash diesel used (obtained from Used/Waste oil), the particulate emission in the chimney is as per standards. Unlike the acid-clay process, this process does not produce any Sulphur dioxide or trioxide. Some odour might be present in the waste oil storage area (feed stock, the most likely source are esters and organic compounds.) 12.3 Odour 22 The table below gives the typical values of the hydrocarbon air emissions in a Used/Waste oil re-refining plant (NON-ACID) in USA with 20,000 MTA capacity Source of odour or emission quantity, mg/litre of air Feed stock storage tank Pre-treatment tank Distillation building Residue storage tank Light oil/ heavy oil storage Blending/filter station 1.5

2 (Source: Environmental considerations: report no DOE/BC/ , US dept of Energy, Washington DC 1983) 1. The storages for the waste oil and for the distilled products are covered tanks. This minimizes the odour of the lighter ends in the air. All processes are under vacuum and hence no chance of the release of the odour. 2. The proposed site of the plant is so conveniently located, to avoid any harmful effect to the surrounding. The effect is almost equivalent to that of a petrol pump or a gasoline station Air Quality The thermal fluid boilers run on Diesel, creating flue gases of 800 cub. Mtr. Per hour and fumes of distillation units and odour present in the used/waste oil are the potential pollutants having negative impact on the air quality. 1. The vacuum pumps exhausts having oil mists as well as the trace amounts of oil vapours from the distillation plant are led to the boiler for burning. 2. The height of Chimney is shall be kept sufficiently high as per norms. A 50-meter chimney is recommended. The amount of particles or so 2 will be negligible, using the low sulphur, low ash diesel used (also obtained from Used/Waste oil), the particulate emission in the chimney are as per standards Liquid Effluents Sources: 23 Water in the waste oil raw material feed Plant runoff water Water from vent gas scrubbers. In general, the characteristics of the liquid effluent depend on the re-refining process and the type of the Used/Waste oil. High vacuum molecular distillation technology offers an advance process in which the above problems are taken care off. In this process, free water if available, is settled with the warming of the feed and with the aid of traces of flocculants. The emulsified water is separated in coalescer filters on line and only the dissolved water is removed in the degassing / drying evaporator under vacuum and condensed. The effluents are expected to contain trace metals (as dissolved / suspended particles) chlorinated solvents, phenols and other organics. In general metals remain in the oil rather than in water. Traces of oil are segregated from water by skimming off oil in neutralization ponds in the premises. More elaborate system of water treatment is not required as the above water is sent to cooling tower for recirculation.

3 Plant runoff water, washings of the floor is similarly taken to this pond for segregation of traces of oil. The amount of water usage / effluents are expected to be 1800 litres per hour. 1) Approximately 5 cub. Mtr. Water is required as replenishment in the cooling tower, Plant floor washings. 2) Approximately 2% water is separated from feed stock oil. A pond with 15 cub. Mtr. capacity will be adequate to handle the above quantity of water, built with in the plant with oil skimmer installed suitably Water Quality There is potential threat that the plant water, removed from oil, plant runoff water and the collection of spills from dykes may contain traces of oil and some harmful metals dissolved in it. 1. Oil/water separator and skimmer: water having traces of oil, is sent to settling water tank and then to the pond where oil is skimmed off in neutralization ponds in the premises with skimmer pipe. This water is recycled with in the plant after skimming hence does not pose any water pollution to the environment Solid Waste The process employs pre-treatment of Used/Waste oil with natural polymer and post distillation bleaching with active clay the following solid wastes are expected: 1. Pre treatment Solid 2. Bleaching clay cake Considering plant running at an average capacity of MT per annum, the following solid waste shall be generated: 2% natural polymer for MT Used/Waste oil feed - = 240 MT 5% clay for bleaching lube stock recovered (say 10,000 MT) = 500 MT Residue approximately 10% of Used/Waste oil feed = 1200 MT Oil/water retained in clay 4% = 20 MT Say Approximately 2000 M. Tonnes of solid waste shall be generated. The residue generation and management is shown in a schematic diagram: 24

4 25 Residue generation and management in the Re-refining process Waste oil Storage(heat) Inline filters Dehydration of oil Water+ dies el+ lighter ends To pond for Separation Water+sludge fraction Centrifu ge/filter Residue if any Clay Bleachin Used clay Molecula r Bottom residue Solids Convert into 1)asphalt extender 2)underwater grease railway crankcase grease etc 3)fuel oil 4) briquetts making 5) brick kilns Lube oil regeneration The Elemental Composition of Distillation Bottoms from Re-refining Facilities as per Annexure F The Composition of Spent Clay Generated during Used/Waste oil Re-refining as per Annexure G Environment Impact of Solid waste: This solid waste produced contains the harmful metals and other effluents separated from the used/waste oil and it is considered a major negative impact, if not disposed off or utilized properly. Mitigation Measures - Utilisation of Solid Waste: 1. Manufacturing of Asphalt extender: Using another polymer, the solid waste is further consolidated into a form, which can be blended with virgin asphalt and used for road surfacing. The solid wastes are residues from distillation bottoms, containing higher boiling and other non-volatile materials. This contains significantly higher metals, ash; sulphur etc. hence manufacturing asphalt extender is most feasible product with solid waste. 2. Manufacturing Briquette 3. Manufacturing under water grease and greases for slow moving gears.

5 Noise Pollution The process does not generate noise pollution in any significant way. The general noise level in the factory premises is: 1. In the covered area db 2. In the open area db The noise levels are much below the acceptable limits Risk of Fire/Accidents/ occupational health & Safety Being a Petroleum Oil re-refining unit there is risk of fire and accidents, but the products do not fall within the low-flash inflammable goods; because the lube oils by nature are high -flash (150 to 340 degree Celsius) Fire hydrants and fire fighting equipments shall be suitably placed in the process area and near the tank farms. An alarm system shall be installed, to be used only in case of an emergency situation Oil Spillage/ Soil Contamination The oil spill may be serious negative impact, since the oil is handled at all points and leaks at valves, filters, process vessel, storage tanks and pipelines may take place. Similarly while loading and unloading spills may occur. There is risk of Soil contamination in case of spill and careless handling during process. Proper preventive maintenance of plant, valves & pipelines shall prevent the leaks inside the plant. Dyke walls\curbing around the tank farms, and concrete floors in pavements and concrete drain in and around the plant periphery to avoid rainwater entering plant area; shall mitigate the risk of soil contamination Ecology/ Landscape and aesthetic environment The plant is proposed to be constructed at hilly range and surrounded by green vegetation. This is seen as a negative impact but the land is rocky, low yielding land. Plot has been lying idle, without any agricultural plantation for past 15 years. This Location i.e. Cluny has been earlier proposed as Industrial zone, by the Government (Source UNEP 1990, Regional Seas, Report & Study No. 125 page 92) Historical Monuments & Cultural heritage There are no Monuments of National Importance, historical or cultural heritage, around the Plant site. There are no water reservoirs or river of national importance around the plant site.