Introduction to Crude Palm Oil (CPO) Dilution

            Control of crude oil dilution has been a formidable problem in process control for palm oil mills. This is due mainly to the difficulty in selecting a suitable flow meter for crude oil measurement, as crude oil is a non Newtonian, thixotropic fluid which cannot be measured using ordinary differential pressure flow meters. As the oil loss in ex-clarification processes is a major source of oil loss in the overall milling operation, there ia an urgent need to improve the control of crude oil dilution to achieve better oil recovery efficiency.

            Before introducing any automatic control system for crude oil dilution, it is necessary to evaluate the available measurement and control instruments for their suitable in terms of cost, accuracy and reliability for the palm oil mill.

            Basically dilution are required by most of palm oil mill to reduce viscosity of palm oil after been pressed. By applying right percentage of dilution it will result effective separation during clarification.

            Normally hot water at 85⁰C of sterilizer condensate been apply as dilution and there are few point of dilution been dose to crude oil passing through pressing machine. Below are few point of dilution point been dose.

(a)  Oil gutter, under press machine

(b)  Press cage

(c)  Digester steam

(d)  Digester discharge chute

(e)  Sand trap

(f)   Crude oil tank open steam coil

(g)  Vibrating screen

            There are various practice for applying dilution to crude oil prior clarification station, such as V notch, orifice plate and insulating valve. Poor dilution will cause poor oil separation at clarification and cause high oil loss at clarifier tank underflow, it also might cause diluted crude oil overflow from oil gutter and sand trap tank due to high viscosity, for certain case it will overload at vibrating screen and screen waste will be oily.

1.2       Important of right dilution rate.

            The main objective of the clarification and centrifuging processes is to separate as much oil as possible from the diluted crude oil. Illustrate conclusively that the optimum oil settling rate for crude oil is achieved with approximately 25% to 35% of water dilution to dilute crude oil. Manual control of crude oil dilution has been found to be highly unsatisfactory due to the following reason.

(a)  High variation in crude oil flow rate due to intermittent operation of the presses.

(b)  Throughput variation in the operation of presses due to varying crop quality and weather pattern. To achieve the required result, it is obviously necessary to look into the possibility of using automatic control of crude oil dilution.

            Good dilution will produce lower oil loss at clarifier tank underflow and effective separation within oil water and solids, it can be verified at sand trap tank, we will be able to see oil sells size of 50 cent coin floating and merge with bigger oil cells. Table below shows some comparison within good and poor dilution by physical view.

No	Good Dilution Rate	Low  Dilution Rate	High Dilution Rate
1.	Oil will flow smoothly at oil gutter and sand trap tank.	Oil will overflow at oil gutter due to greater viscosity.	Oil will flow faster without any oil at top surface.
2.	Able to see oil cell size of 50 cent coin floating to top surface at sand trap tank.	Only fine oil cell will float and level of sand trap tank will increase due to increase of viscosity.	Sign of emulsification at top surface of sand trap tank.
3.	Smooth distribution of screen waste at vibrating screen mash.	Most of screen waste will accumulate at middle of vibrating screen and will cause overloading at screen mash.	Screen waste will travel fast at screen mash and inlet feeding feed will looks watery.
4.	Good separation and clarifier tank with low oil loss at sludge underflow.	Will cause high oil loss at clarifier underflow, Low moisture content but high NOS.	Will also cause high oil loss at clarifier tank underflow, emulsify sign at top of oil surface, high moisture contain but low NOS contain.

Table 1.1: Comparison within  dilution rate.

            Below are some pictures shows physical condition of good dilution rate and poor dilution rate, all pictures and situation are base on my Mill condition and process flow.

Figure 1.1: Picture of low Dilution 

Figure 1.2: Picture of good dilution rate.

Figure 1.3: Picture of good dilution, view from sand trap tank.

Dilution rate are normally determined by type of planting material and weather changes, during high rain fall dilution rate should be lower and during dry season dilution rate should be higher. Table below shows dilution rate for Genting Trushidup Oil mill by comparing with rain fall (mm) for average per day for two weeks period.

No	Rain fall (mm)	Dilution rate (%)
1.	0-7	27
2.	8-20	25
3.	21- 35	22
4.	35-85	20

Table 1.2: Correlation within rainfall and dilution rate

            From table above, it is extracted base on Genting Trushidup Oil Mill data study that been updated on December 2011. It obviously shows rain fall are correlated with dilution rate and if been plotted in graph it reacted against both units.

1.3       How to determine best dilution rate.

            In order to determine the best dilution rate for each mill we need to carry out settling test, sample of undiluted crude oil bust be taken at right place with all source of water must be eliminated, objective of this test are to check with what dilution rate, crude oil will settle base on fasters time, temperature of this test must be same as clarifier tank, for Genting Trushidup Oil Mill case we are applying 85⁰C and test been carry out for 10 minutes.

Figure 1.4 : Settling test

Content	20% Dilution	22% Dilution	25% Dilution
Oil (mm)	20	25	18
Sludge (mm)	70	68	65

Table 1.3: Settling test data

            Picture 1.4 shows how settling test been carry out, 3 bikers with 500ml been place with 20%, 22% and 25% dilution and undiluted crude oil been place in it, retention time for this test are 10minutes.

            After 10 minutes, measure the high of oil settled and high of sludge, from table 1.3 it shows 22% dilution is the most suitable to be implemented at process during this period, during this test been carry out, need to ensure temperature are the same as clarifier tank temperature.

            Dilution rate might not be same with other oil mill and even at same mill it will slightly increase or reduce depends on weather, planting materials and FFB quality.

Figure 1.5: picture of over dilute DCO.

           

Breeding Arowana

Breeding Arowana

The Silver Arowana prefers a 125 gallon tank with a fine gravel bottom, loosely planted, and soft, peaty water with lots of open space above for swimming. The aquarium must be fitted with a tight, heavy cover because the Arowana will jump, particularly when after prey. After breeding, the male Silver Arowana is responsible for carrying the large eggs in his mouth where they mature in 50 to 60 days. When young, these fish are easily harassed by more aggressive species such as Cichlids, Knife fish, large Plecostomus, Catfish, and Ornate Bichirs make good tank mates for the Silver Arowana. A carnivore, the Silver Arowana will eat other smaller fish, water fleas, mosquito larvae, as well as freeze-dried ocean plankton, krill and pellet foods.

HABITAT: Bangladesh.

Spawning behavior

The fish shows unique courtship behavior. The courting chase takes place from several days to weeks before the pair starts to mate. They will swim in circles with male chasing the female.

About 1-2 weeks before spawning takes place, the fish swims side by side and perform body contact between pair. After the courtship behavior takes place, the female will lay the eggs and then promptly fertilized by the male. After fertilization, the male picks up the eggs and incubates them until the fry can swim and survive independently.

The eggs are large in size about 8-10mm and yolk rich, hatched about one week after fertilization. After hatching, the young larvae continue to live in the male’s mouth for further 7-8 weeks until the yolk sac was totally absorbed. The size of the fry was 45-50mm before they are move out of the males’ buccal cavity.

REMOVING OF EGGS FROM MALE'S MOUTH

In the study, the fertilized eggs were forced extruded from males’ mouth at the 30th day after spawning. The average number of the eggs produced in a single brood was 21 larvae with the maximum number recorded 29.

The eggs are orange-red in color and are large in size with diameter 16-20 mm. Once removed from the parents’ mouth, the half-developed larvae were incubated in glass aquarium tanks, measuring 90x45x45cm. Water temperature is kept around 27-29 degree C using a thermostat heater and dissolved oxygen is maintained at about 5 ppm (mg/l) through continuous aeration of the water. During the first few weeks when the larvae are still having large yolk sac, they tend to remain at the bottom of the tank most of the time. The fry start to swim upward periodically when the yolk sac becomes smaller.

Using the in vitro hatching technique, the survival rate to free swimming stage achieved is 90-100%. The fry will swim freely on the 7th week. Supplementary external live feed (young guppy) was given at the early free-swimming stage to avoid the fry from attacking each other. At the age of the 6th month the fingerlings were reared individually in 75 x 45 x 45cm re-circulating water system tank. At this age the fry measured about 20-25cm length and were ready for market.

Eight pieces of Malaysian Golden Dragon were reared in 5m x 5m concrete tank and water depth about 0.5m. pH of water was maintained between 6.8-7.5 and temperature 27-29oC. A ’spawning room’ were built at one corner of the concrete tank. It is hoped that the condition will create a natural living environment for the fish. Live feed such as crickets, wild guppy, freshwater prawn (Macrobrachium lanchestrii) and gold fish were given daily. Pellet feed was also given as the supplementary food.

MATURITY

The fish attain first maturity from the 4th year onwards and measure between 45-60cm. The fish spawn throughout the year with the peak season occurring between July and December. In nature the male incubates the fertilized eggs in its’ bucca cavity until the fry is free swimming at about 2 months.

Sexual differences are indiscernible in juvenile stage and become apparent after maturity is reached in about 3-4 years. Male posses slimmer and shallower body depth, bigger mouth and more intense color then the females.

The reasons for having wider mouth and deeper lower jaw in males are for eggs incubating purposes. The size of the males’ head is relatively bigger. Male is more aggressive and leading in competition for food.

A brooding male can be recognized by its remarkable brood pouch underside its mouth.