Eco-efficiency Study in a Sunflower Oil Mill

Sibel Uludağ-Demirer (Dpt. of Industrial Eng., Çankaya University, Ankara)

The share of SMEs in:

total economic growth

industrial pollution

90 % in Europe (Hillary, 2000)74 % in Turkey (DIE, 1996)

70 % (note that the environmental data is very limited for SMEs) (Hillary, 2000)

The major drivers for taking environmental actions for SMEs:

Social Responsibility Legislation Public Awareness Financial Benefits Internal/External Benefits Improved Image

Eco-efficiency is a management tool encouraging

industries to create more value with less impact.

Eco-efficiency allows industries to be more profitable, makes industries to be environmentally responsible, improves the performance of industries, minimizes waste production, avoids end-of-pipe solution or lowers its share in

waste management.

lowering the chemical usage, preventing material loss during storage, handling,

transportation, operating the units at optimum conditions (amount of

additives, optimum T and P, etc.) to achieve higher performance,

searching for water and energy saving opportunities, environmentally and economically sound residual

management opportunities.

Eco-efficiency focuses on practices throughout

the industry, such as,

Cleaner Production

Eco-efficiency

Eco-efficiency applicationsprecondition the industry for cleaner production studies, while implementing cleaner production strategies improves the eco-efficiency of the industry.

Eco-efficiency focuses on the economical efficiency that will result in environmental benefits while cleaner production targeting environmental benefits, which brings in economical benefits in most of the applications.

Eco-efficiency applications are very

suitable for SMEs due to:

their low or no investment requirements short pay-back periods easy and fast applications direct effect on reducing the environmental

impacts

Methodology for eco-efficiency

A- Analysis of the production by auditing the entire system

collect data about the production, such as, raw materials used, material handling techniques, processes and their operational conditions, generation of product and waste, waste management practices, etc.

develop process flow diagrams for each department and construct mass/energy balance.

define and predict immediate environmental benefits as outcomes of a better operational and waste management using typical indicators, such as, use of hazardous compound, use of obscelete technologies, production of waste in large quantities, lack of waste management.

recognize the existing eco-efficiency applications in the system and analyze their benefits.

Methodology for eco-efficiency-cont.

B) Identification of eco-efficient opportunities for the activity

analyze the problems related with material selection, handling and facility layout

analyze the mass/energy balance to define material loss and wasted energy for each unit process

compare the operational conditions with the conditions reported in relevant literature and sectoral guidelines or fact notebooks.

investigate a better waste management focusing on minimization.

Methodology for eco-efficiency-cont.

C) Evaluation of Opportunities

Technical feasibility

Economical feasibility

D) Implementation

Objectives of the case study

Company Name: Eskişehir Oil Industry carrying out an industrial audit to collect the data

required for developing process flow diagram and material balance

determining the points of eco-efficiency applications reporting and testing the required changes and

modifications proposed estimating the benefits calculating the pay-back period when initial

investment is necessary

Facts of Eskişehir Oil Industry

Product: vegetable oil from sunflower seeds (RavinTM)

Annual turnover: 3.5 million USD

Number of employees: 23

Capacity: 12 000 tons from 30 000 tons of seed

Seed composition: 40-48 % oil and 8 % moisture

Other activities: refining crude oil (corn, cotton) in the periods of seed shortage

Wastewater treatment plant: simple physical and chemical treatment units (neutralization and sedimentation)

Methodology of the case study

Entire production cycle was observed. Process flow diagram was developed. Existing eco-efficiency applications were determined. New eco-efficiency applications and their pay-back periods

were determined.

An example for the checklist used in the study

based on hexane (solvent):

Raw material or component name Hexane

Annual Consumption 15 tonnes

Consumption per unit production 16 kg

Purchase cost 0.46 USD*/kg

Annual purchase cost 6,940 USD

Property causing environmental impacts Volatile organic

Method of supply Tankers

Storage method Tank

Transportation method in the plant Pipelines

Expiration life 2 years

Is it possible to return the packages to supplier? No

Is it possible to return the expired material to supplier? No

Calculation of pay-back period

Pay-back period: the length of time it takes for the revenues froma project to equal the initial investment costs.

This approach was adopted in this study due to: its simplicity existence of no alternative eco-efficiency applications for the

same problem to compare in the studyalthough there are some drawbacks in using the payback period,such as ignorance of the time value of money not showing the costs and savings beyond the point where the

project pays for itself.

Process Flow Diagram and Material Balance based on a Unit Production in Eskişehir Oil Industry, Eskisehir, Turkey (annual capacity=12,000 tons of vegetable oil).

Pulp with25% of Oil

Content(26000 kg)

PHYSICAL PROCESSES

Refined Oil(12610 kg)

Pulp(19500 kg)

Sunflower Seed(33475 kg)

EXTRACTION

REFINING

FILLING

Crude Oil(6500 kg)

ForeignMaterials (975kg)

Crude Oil(6500 kg)Crude Oil

(13000 kg)

Hexane(30000 kg) Hexane

(29.984 kg)

Phosphoric Acid (13 kg)NaOH (0,13 kg)Trisyl® (5 kg)Bleaching Clay (30 kg)Citric Acid (1 kg)

Residual Soap (78 kg)Filter Sludge (50 kg)Stearin (16.9 kg)

Packed Oil(12610 kg)

Current Eco-efficiency Applications

Sieves used to remove the foreign materials from the sunflower seed have been installed individually resulting in savings in energy and increasing the life span of the sieves.

The sludge produced in bleaching unit is burned in the incinerators for heat spacing, which is a solid waste minimization practice.

The by-products, pulp, stearin and fatty acids are sold to the animal fodder and soap manufacturers respectively.

They reuse the plastic containers of the phosphoric acid for storage in the plant.

The packaging department is donated by automated pumps preventing any product loss.

Recommended Eco-efficiency ApplicationsI. Applications with no pay-back period calculations The use of phosphoric acid in the degumming process can

be replaced by citric acid, which is less expensive and easy to apply.

The water used for cooling the steam (20 m3/hr) can be recycled and then reused in the process.

The steam used in the physical processes, refining, and extraction can be used for space heating in filling station, which has no heaters.

The temperature in the odor control unit is set to 220°C, which is in the range of a typical temperature used in the odor control units (180-260°C). They can save significant amount of energy by lowering the temperature in this unit by keeping the odor removal at the desired level.

Recommended Eco-efficiency Applications-cont. II. Applications with pay-back period calculations The Problem: Sunflower seed loss (923 kg/year)

during the sieving process

The Solution: Raise the height of the sieves at least by 3 mm using a steel sheet keeping the swinging rate the same.

Economic Analysis:

Investment cost 12.45 USD*

Annual savings 282 USD

Payback period 16 days

*The purchase of a steel plate (6 USD/m2) with an area of 2 m2

II. Applications with pay-back period calculations (cont.)

The problem: Optimization of the amounts of bleaching additives (bleaching clay and TriSyl®) to decrease the oil content of the bleaching sludge.

The solution: The amounts of additives were adjusted to the recommended amounts in the literature and oil content of the sludge produced before and after changing the amounts of additives was determined experimentally using hexane extraction method.

Recommended Eco-efficiency Applications-cont.

Purpose: determine the oil content of the sludge produced in the bleaching unit.

Method: 1. Known weight of sludge was extracted using hexane for 6

hours in a 250 mL Soxhlet apparatus. 2. Solvent was then evaporated under reduced pressure at

40°C. 3. Desolventized oil was filtered to remove the particulates

and weighed. 4. The water content of the sludge was determined using

xylene.

Recommended Eco-efficiency Applications-cont.

Experimental Work

Additives Current Doses (kg)*

Cost of the current doses (USD)

Proposed Doses(kg)

Cost of the proposed doses (USD)

Optimum doses** (kg)

TriSyl® 5 7.6 10 15.0 10.4

Bleaching clay 30 18.0 15 9.0 13

Total Cost 25.6 24.0

*based on 50 kg sludge production.** Altiokka and Altay (1991).

Recommended Eco-efficiency Applications-cont.

Experimental results showed that the oil content of the bleaching sludge decreased to 25% from 41% (dry weight) after changing the amounts of additives.

Economic Analysis:Investment cost none

Annual savings in chemical purchasing

1,280 USD

Annual savings by recovering the oil from the sludge*

9,932.3 USD

Payback period immediate

*Recovered oil is assumed to be processed with 100% efficiency to produce the vegetable oil.

Recommended Eco-efficiency Applications-cont.

Other outcomes of the proposal:

Rate of filtration increases. Frequency of filter cleaning decreases. Amount of sludge produced decreases. Loss of natural antioxidants is prevented.

Recommended Eco-efficiency Applications-cont.

II. Applications with payback period calculations (cont.) The Problem: Significant amount of hexane loss during the

production (atmospheric emissions, residual hexane in the pulp, leakage from the tank, volatilization,etc.)

The solution: Recovering the hexane vapor mixed with steam and pulp, reducing the hexane emissions by installing the proper equipments.

Economic Analysis:

Investment cost 28,465 USD

Annual savings 6,940 USD

Payback period * 4.1 years

* excluding the operational and maintenance costs.

Recommended Eco-efficiency Applications-cont.

Other Outcomes:

• Protection of worker’s health and environment by preventing the hexane emissions,

• Increasing the quality of the oil and other by-products by reducing the residual hexane.

Recommended Eco-efficiency Applications-cont.

Conclusions Making the management and employee recognize the current

eco-efficiency applications motivated them in involving proposed eco-efficiency applications.

The benefits of some of the proposed eco-efficiency applications could not be determined due to the difficulties in valuation the impacts and in testing the proposed changes on the process.

The proposed eco-efficiency applications to prevent the seed loss in sieving process, to reduce the amount and oil content of the bleaching sludge were implemented immediately by the industry.

Although the hexane recovery project had a longer payback period, the management agreed on investing on this project in near future considering the monetary, health and environmental outcomes of the project.

This study showed that the simple applications may result in significant benefits and reduce the environmental impacts in SMEs.