Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02707573 2010-06-30
DESCRIPTION
TITLE OF THE INVENTION
Centralized Sump Oil and Acid Oil treatment process and System
BACKGROUND OF THE INVENTION
This invention involves an environmental governance method, a specific
centralized sump oil and acid oil treatment process and system.
With an in-depth awareness of the people who have been faced with more
and more serious environmental pollution in the world, the cleaning and
treatment of
sump oil and acid oil of the oilfield attract more and more attentions. The
oilfield
exploitation brings a great amount of sump oil and acid oil which are
difficult to
dewater. Such non-standard oil containing water, impurity and high viscosity
was
sold to the local firing enterprises and refineries at a lower price in the
past as the
firing oil and non-standard oil. Considering that it is not decomposed and
treated,
such sump oil and acid oil contain a great amount of harmful chemical
compositions
and it brings serious pollution and damage to the surroundings of the oilfield
and the
production equipment. Additionally, the penetrating sour gas volatilized by
the acid
oil pollutes the air of surroundings. Such odor can be smelled a few
kilometers away
and it seriously damage the physical health of employees in the oilfield. The
acid
liquor causes the corrosion to the mechanical equipment. The coils in the oil
storage
tank and the suction pumps are replaced regularly. In this way, it greatly
increases
the production cost.
The acid liquor-contained sump oil has strong corrosion, and it easily
reacts with the colloid and asphaltine to form the particles in suspension. It
hinders
the settlement and the alkali cannot be neutralized so that it is difficult to
separate
the oil and water. Thus, it is a difficult problem for many oilfield experts,
for that the
1
CA 02707573 2012-08-14
acid-contained sump oil has great viscosity and proportion. A large amount of
acid
water cannot be separated only by the way of settlement. The simple treatment
process has no effects on the viscosity and acid oil in the sludge and it has
no
effects on purification. Therefore, the ideal treatment approach is required
for
treatment and recovery.
Although there are many patent applications in treating oil sludge and
sump oil, for example, China patent application numbers 200510045971.9
(publication number: CN1669960A), 200710064407.0 (publication number:
CN101054244A), 200610046997.x (publication number: CN1896186A) and
200710011114.6 (publication number: CN101041541A), and they published the
treatment methods of heavy oil sludge, tank cleaning oil sludge, sewage and
crude
oil dehydration, yet the proper measures against the sump oil and acid oil are
not
developed. It also does not encounter the difficulty of oil, water and
impurities in the
sump oil and acid oil.
BRIEF SUMMARY OF THE INVENTION
In order to solve the recovery treatment difficulty of the sump oil and acid
oil, the main purpose of this invention is to provide one effective treatment
process of
sump oil and acid oil to easily separate the oil, water and impurity in the
sump oil and
acid oil. Meanwhile, this process simple with low treatment cost.
This invention provides a specialized treatment system in the said way.
The centralized treatment process of sump oil and acid oil, consists of that
(1) the sump oil is filtered by the coarse filter for removing the coarse
impurities; (2)
enters to the reaction kettle; the compressed air is introduced from the coil
at the
bottom of the reaction kettle with the pore diameter of 60-110pm and it is
stirred after
the tiny bubbles are produced; at the same time, the sodium carbonate solution
with
2
CA 02707573 2012-08-14
the weight percentage of 7-18% is added to the sump oil till the PH value of
the
sump oil keeps about 6.0-8.0; then the emulsion splitter with the volume ratio
of 0.4-
0.8% is added to the sump oil in the kettle; then the flocculating agent with
the
volume ratio of 0.1-0.5% is added in the sump oil in the kettle for further
reaction.
The compressed air is provided for 2.5-3.5 hours; (3) the compressed air is
suspended and it is settled for 4-6 hours; (4) the detergent oil at the upper
level of
the reaction kettle is provided to the purification tank, the detergent oil in
the said
purification tank is filtered by the fine-mesh filter at the mesh diameter of
1-1000 ,u. m;
then it is heated to 110-120 C and it is dehydrated in the dehydrating tower
under
common pressure, then it is heated to 70-90 C by the heat exchanger; then it
is
delivered to the dehydrating tower under the reduced pressure for dehydration
under
20-70kPa to obtain the national crude oil; the sewage produced after
condensation
of the water vapor dehydrated by the dehydrating tower under normal and
reduced
pressure and the intermediate sewage are delivered to the sewage tank. The
sewage in the sewage tank is delivered to the vertical natural oil removal
tank to
separate the oil and water by way of gravity at a flow speed of 0.5-0.8mm/s.
The
water outlet is drained after filtering by the oil-water filter; the oil
sludge at the upper
level is retained in the reaction kettle, and the oil sludge in the reaction
kettle is
rinsed with the sodium hydroxide solution at a temperature of 65-75 C and the
weight percentage concentration of 10-20% at a proportion of (1.5-2.5):1 for
15-25
min, and settled for above 2.5 hours. The detergent oil after washing with hot
water
at the upper level is delivered to the purification tank and the intermediate
soda
solution is collected in the soda solution tank, and the sediment impurities
at the
bottom of the reaction kettle are delivered to the sludge solidifying tank
with the
sludge pump.
3
CA 02707573 2012-08-14
The acid oil in this invention refers to the acid-contained sump oil.
In this invention, the soda liquor is added when the fine air bubbles and air
suspension are made. After full reaction, the demulsifying agent and
flocculating
agent are added to successfully break the suspended particles in the oil
sludge and
easily settle and separate the oil and water. In addition, the process is
simple with
low cost.
Further, the sump oil filtered by the coarse filter to remove the coarse
impurities is delivered to the reaction kettle after the oil pump, and the
sump oil in the
reaction keeps heats to the temperature of 55-70 C and the said sodium
carbonate
solution is added in the sump oil so that PH value of the sump oil maintains
6.0-8.0,
then the temperature of the sump oil in the kettle increases to 70-90 C, and
then the
said emulsion splitter and the said flocculating agent are added.
Further, the said emulsion splitter is the non-ionic surface active agent with
the trunk chain of polyether, with the terminal base containing hydroxide
radical,
amino group, ether group and carboxyl. The said flocculating agent has the
main
composition of polymerized alumina.
Further, the said sodium carbonate solution is delivered to the reaction
kettle by the stainless steel magnetic pump for delivery of sodium carbonate
solution.
Further, the said fine filter is made by the bag-type fine-mesh filter with
the
filter precision of 1-1000pm.
Further, the said oil-water filter consists of the coarse filter tank puddler
for
coagulation, separation and removal of oil, levitated sphere maze for removal
of
turbid by microvortex, annular space for removal of dregs and the walnut shell
medium for filter and purification.
4
CA 02707573 2012-08-14
Further, the said sludge solidifying tank takes the weight of the sludge as
the reference, and 6-9% of Portland cement, 2-5% of quicklime and 0.5-2% of
alumina are added for the purpose of solidifying the sludge after mechanical
stirring.
One central treatment system of sump oil and acid oil, wherein, it consists
of the coarse filter for removal of coarse impurities, the oil pump and the
reaction
kettle for delivery of sump oil, the stainless steel magnetic pump for
delivery of acid
or alkali solution, purification tank, sewage tank, the bag-type fine-mesh
filter with the
precision of 1-1000pm, the dehydration system under normal and reduced
pressure,
the vertical natural oil removal tank for coagulation, separation and removal
of oil,
levitated sphere maze for removal of turbid by microvortex, annular space for
removal of dregs and the walnut shell medium for filter and purification.
The basket-type filter can be bought from Shandong Xulong Petrochemical
Equipment Co., Ltd. HF-B01-LCR LC oil pump from Dandong Yiyang Pump Industry
Technology Co., Ltd., HF-01B special sump oil demulsifier from Tianjin
Wanfengshun Science Trade Development Co., Ltd, HF-02 flocculating agent from
Hebei Huarui Lanxing Chemical Industry Construction Materials Co., Ltd; HF-001
bag-type fine-mesh filter from Shijiazhuang Baisite Filter Equipment Co.,
Ltd., and
HF-E01 oil-water filter from Yangzhou Xiongdi Environmental Equipment Co.,
Ltd.
The detailed description of the technical plan of this invention is shown
below:
1. Separation of oil, water and impurity:
The reason why to decompose and treat the sump oil and acid oil difficultly
is that such oils are placed for long term in an open air with the low light
compositions and the water, heavy compositions and sludge of the main
compositions. The proportion of sump oil is close to the water and the sump
oil itself
CA 02707573 2012-08-14
contains the asphaltine, colloid, naphthenic acid and natural emulsifier
enriched on
the surface of the oil and water to form the stable interfacial film. At the
same time,
acted by the microorganism and acid liquor, the asphaltine, colloid and heavy
compositions in the sump oil degrades and gathers into a mass. Then the added
chemical agent is mixed with the natural emulsifier to make the sump oil
difficult to
treat. Thus it becomes the multiple phase of crude oil emulsion that small
stable oil
drops contain water and the water contains the oil drops.
This invention firstly neutralizes and decomposes the residual acid in the
sump oil to make PH value maintains at a range of 6-8. After decomposition of
residual acid, the emulsifier in the sump oil is diluted and transformed to
lower the
emulsification ability of the emulsifier, reduce the trnsion of the oil sludge
interface,
break the balance of the oil ion, and lower the surface strength of the drops
so that it
is easy to gather into the larger drops.
After heating settlement, the sludge and water in the sump oil can be
dehydrated. Then the acid liquor in the acid oil of the sump oil is decomposed
so that
PH value is neutral. Finally, the sump oil is fully dehydrated under normal
and
reduced pressure. The study shows that the proper electrolyte is added to
increase
the charging density of the system at the time of emulsion breaking for the
purpose
of driving that the oil is separated from the surface of the solid particles
of the sludge,
so that they can replace the oil compositions and affix on the surface of
particles and
disperse the particles and it creates better conditions for oil removal from
the solid
particle surface.
In consideration of high viscosity of the sump oil, serious emulsification,
strong adhesive force of particles among solid, solid and liquid and lower
density
difference, it is determined to adopt the inversed emulsion breaking and
6
CA 02707573 2012-08-14
electrochemical reaction driving, in addition to the heating to achieve the
purpose of
removing the sludge and water in the sump oil. The surface active agent and
flocculating agent are taken as the chemical agent. The role of the surface
active
agent is to make the transition of the original emulsion that the water-in-oil
emulsion
is converted to the oil-in-water emulsion. For that the oil-in-water emulsion
has poor
stability, the water and sludge is easy to settle; the flocculation refers to
a process of
coalescence of large particles after stability loss of colloid and impurity
(or absorption
and bridging of polymer substance). The role of the flocculating agent is to
develop
the electrochemical reaction so that the colloid and impurity contained in the
sump oil
after stability loss are formed to the larger particles to remove the small
impurities
and sludge and develop the emulsion breaking.
The emulsion splitter adopted in this invention is HF-01B special sump oil
emulsion spillter, which is the polycomponent non-ion surface active agent
generated after action of polyoxyethylene, fatty amidogen ether and several
base
materials with the trunk chain of polyether structure and with the terminal
base
containing hydroxy group, amino group, ether group, carboxyl and poly
hydrophilic
functional groups. It is a kind of agent with sound water solubility. In the
sump oil,
this agent is added in proportion to lower the oil-water interfacial tension
of the sump
oil, break the balance of electric potential, change the organic oil soluble
salt to water
soluble salt, easily gather to large drops. Finally, the compositions of the
oil are
separated for the purpose of desalting, impurity removing, dehydration and
emulsion
breaking. The technical indicators of HF-01 emulsion splitter are shown in
Table 1
with sound water solubility. When diluting, it is stirred slightly. Within
three minutes, it
can be dissolved fully. The W/O sump oil with high acid value, paraffin
content, water
7
CA 02707573 2012-08-14
content of 50% and strong hydroscopicity to about 10%. The small quantity of
the
agent is used with no pollution in a safe and reliable manner.
The commonly-used coagulating agents are aluminium sulphate, ferrous
sulfate, ferric trichloride, bodied ferric sulfate and inorganic coagulating
agent,
polyacrylamide, propylene, 2-propylene 2-amine and organic coagulating agent.
This
invention has a preference of HF-02 flocculating agent, which is a new high
polymer
flocculating agent with the main composition of polyaluminium chloride
(abbreviation
of PAC), chemical structural formula of [Al2(OH)nC16-r]m, where, 15n55 , m<10
is
between AICL3 and Al(OH)3. The bridging polymerization is made by hydroxyl
group.
The molecular contains unequal hydroxyl group with strong bridging absorption
performance. During hydrolysis, electrochemistry, agglomeration, settlement,
absorption, physical change and chemical change take place, characteristically
of
that (1) the small quantity is used during coagulation; the flocculating
constituent is
formed quickly; the settlement is made at a high speed; the reaction
settlement time
is shortened and the treatment ability is improved. (2) more flexible, pH more
flexible
than AL2(SO4)3 and temperature more flexible than AL2(SO4)3; (3) 5-8 times as
good
as aluminium sulphate and 3-5 times as good as ferric trichloride, better than
ferrous
sulfate and alum; (4) no secondary basic accelerator, 30-70% lower than low
molecular flocculating agent on the cost; (5) quick solution, low corrosion,
removal of
iron, manganese, arsenic, fluorine, beryllium and chrome in the source water
and
good effects on removal of radioactive contamination and organic coloring
matter in
the water. The indicators are shown in Table 2.
For the said process, this invention adopts the method of air floatation to
quick up the chemical reaction, the emulsion breaking and separation of
compositions of the sump oil. The air floatation method is an effective method
to
8
CA 02707573 2012-08-14
treat the high water-contained sump oil. The water content in the sump oil of
the oil
field increases by above 50% and the air floatation method is used to quick up
the
separation of the compositions of the sump oil. It means that the high-
pressure air is
introduced to the high-water sump oil to produce a great amount of the tiny
bubbles
with an average diameter of 80pm so that the petty oil balls in the sump oil
affix on
the air bubbles. It floats on the water surface with the air bubbles and it
greatly
quickens the process of separation and the air bubbles produced by the air
floatation
play a role of stirring, so that the added agent fully reacts with the sump
oil. The
specialized stirring equipment is unnecessary, killing two birds with one
stone. After
stirring and separation by way of air floatation method, the settlement method
is
adopted to separate any sludge.
The basket-type filter is preferred in this invention and it is a coarse
filter to
remove large impurities. The basket-type filter is a kind of the advanced and
practical
filter with thick pipe, large quantity of dirt collection, high pressure
withstand, and
easy installation and cleaning. It is applicable for filter of large particles
in oily water.
It is installed on the pipe to remove the large solid impurities in the fluid,
so that the
production equipment is not blocked and work normally to achieve the stability
of
process and safeguard the safe production. The basket-type filter in this
invention is
made of stainless steel mesh grid, characteristically of easy installation,
removal,
cleaning and strong filter. The production experience shows that it is
applicable to
remove the large particles of impurities in the sump oil and acid oil.
HF-B01-LCR LC oil pump is preferred as the oil pump for delivery of sump
oil in this invention. It is primarily used for delivery of sump oil at the
time of loading,
unloading and emptying. This oil pump is improved on the basis of HF-LC pump
and
it adopts the multi-sealing mode to ensure that the oil pump does not leak if
it works
9
CA 02707573 2012-08-14
for long term. The flow rate increases by 200m3/h to meet the different
requirements
on flow during production. The drive modes of HF-B01-LCR oil pump are
flexible,
with two drive ways of reducer and belt. Meanwhile, this pump has low rotate
speed,
effectively lowering the pulse vibration and noise, high efficiency, saving
energies;
small in size, reducing the floor area. It can be moved entirely during
production,
easy maintenance, counter rotation. It has strong self-suction and easy
operation
without oil with the suction length of 6m. To deliver the high-viscosity
medium, the
pump body is designed with the insulation cavity and it is heated with the
steam or
conduction oil, to ensure the continuous or discontinuous work of the oil pump
and
normal operation in the cold winter in northern area.
HF-B02-IMC stainless steel magnetic pump is preferred for delivery of acid
or alkali solution. It is a new product with the state-of-the-art design after
any drive
pumps are integrated, primarily used for delivery of acid or alkali solution
during
production. In accordance with IS02858, its flowed passage parts are made from
the
stainless steel. The explosion-proof motor is used and it has sound corrosion
resistance to the organic acid, organic compound, alkaline solution, neutral
solution
and other multiple gases. The double helix carbon graphite bearing is well
matched
with the hard alloy bearing with strong wearing resistance and service life.
It is an
ideal pump for leakproof delivery of corrosive medium. It is single-stage
single-way
suction cantilever type. At the time of delivery of high-temperature medium
(the
temperature of delivery medium5400 C), the water cooler is not used, but the
intermediate coupler is installed. For the purpose of repair, the circuits and
motors
are not disassembled but the intermediate coupler is only disassembled. The
specific
parameters are as follows: the inlet calibre of 80mm, outlet calibre of 50mm,
flow of
CA 02707573 2012-08-14
50m3/h, pump head of 80m, motor power of 37kw, motor speed of 2900r/min,
pressure of 1.6mpa and temperature of -20 C-400 C.
2. Detergent oil dehydrating
After the residual acid, sludge and water in the oil are removed in the said
processes, the detergent oil meets the international standard, but 10%-20%
water is
still retained. The structure of such water and oil is stable, and it is
difficult to
separate in a chemical method. In this invention, the physical method and the
way of
atmospheric and vacuum are adopted to remove the remaining water in the oil.
For
that the boiling point of the water is different from that of the oil, the
water is fully
gasified at a temperature of 120 C under atmospheric conditions. However, the
sump oil is placed in an open air for long term. The distillation test shows
that no light
compositions of the sump oil are shown before the temperature of 120 C. It
also
represents that the light compositions of C1¨05 in the sump oil have been
volatized.
Therefore, the co-boiling of water and oil is not produced. Under vacuum
station, the
boiling point of water is reduced and it can be gasified at low temperature.
The water-bearing oil in the oil cleaning tank is filtered by the fine filter
to
remove the petty impurities. The test shows that, the bag-type fine filter is
most
applicable to treatment of the fine filter in the crude oil. HF-001 bag-type
fine filter is
preferred as the bag-type fine filter with the precision of 1-1000pm. The
filter area is
60% more than the standard filter bag in the same size. It is
characteristically of high
passage, high filter precision, large filter area, strong dirt collection,
long replacement
cycle of filter bag, sound sealing, easy replacement of filter bag, easy and
quick
operation. It is applicable to filter of any petty particles (less than
1000ppm) for the
fluid with the precision range of 1-1000pm and 1-1000m3/h. HF-001 bag-type
fine
filter is a easy, effective and commonly-used fluid filter system, composed of
11
CA 02707573 2012-08-14
container, bag and support. The detergent oil filtered enters to the filter
barrel under
the pipeline pressure. After electrolytic polishing for punching, it enters to
the filter
bag supported by the filter basket to properly separate the solids and fluid
so that the
detergent oil is fully filtered. Different filter precision depends on the
filter bag with
different precision. For that the liquid medium is flowed from the top end of
the filter
bag after the liquid medium enters to the filter, so that the liquid can be
evenly
distributed at the surface of filter of the whole filter bag and the
distribution of the
fluid on the whole surface is constant. With less adverse effects of the
stirring motion,
the solid matters in the liquid are retained in the bag to obtain the clean
fluid. The
medium has characters of great passage, pressure drop, easy operation and
economical rationality.
After the impurities are removed from the detergent oil by fine filter, it
enters the heat exchanger for heat exchange and heating. The hot fluid for
heat
exchange is from the international crude oil under atmospheric and vacuum. HF-
D01
shell-and-tube exchanger is preferred in this invention. It is composed of
shell, heat-
transfer pipe bundle, tube plate, traverse baffle (stop plate) as well as
header. It is a
dividing wall type heat exchanger with the wall surface of pipe bundle
enclosed in the
shell as the heat-transfer surface. It has simple structure and reliable
operation
under high temperature and pressure. It is a commonly-used type. The shell is
columnar and the pipe bundles are installed with both ends of the pipe bundles
on
the pipe plate. The cold and hot fluids for heat exchange are flowed
respectively
inside and outside the pipe. To improve the individual heat transfer
coefficient of the
fluid outside the pipe, the numerous stop plates are installed in the shell.
The stop
plate can improve the speed of fluid and drive the fluid to conduct the
transverse
12
CA 02707573 2012-08-14
passage of pipe bundles for several times as the specific routes and increase
the
turbulence extent of the fluid.
The temperature of detergent oil after heat exchange by the heat
exchanger reaches about 80 C, then it is heated to 120 C in the atmospheric
tubular
heater through the pump. The tubular heater is composed of radiation chamber,
convection chamber, funnel, waste heat recovery system, burner and ventilation
system, etc. The radiation chamber is the core part of the heating furnace, as
the
hottest part in the entire furnace. 70%-80% of the heat load of the entire
furnace is
assumed by the radiation chamber. The convection chamber conducts the heat
exchange with the fume from the radiation chamber. In the convection chamber,
rows of furnace tubes are placed. These pipes are flushed by the fume at a
high
speed for the purpose of effective heat exchange. The chimney is a passage for
fume exhaust. At the same time, control of the discharge of fume is to control
the
combustion efficiency of the radiation chamber, so as to control the
temperature of
the radiation chamber, characteristically of high temperature (flame
temperature of
1000-1600 C), large heat transfer capacity (heat transfer intensity of furnace
pipe of
330000kj/m2h). The heating furnace takes the natural gas in the oilfield or
the coal
gas produced from the coal gas generator as the fuel to generate the high-
temperature flame and fume. With the furnace pipe wall, the crude oil flowed
in the
furnace pipe is heated to meet the temperature needed.
After the detergent oil is heated to 120 C in the atmospheric heating
furnace, it is dewatered in the atmospheric dehydration tower. After the oil
enters to
the atmospheric tower, the water molecule contained is vaporized immediately.
The
crude oil in the tower flows to the tower bottom along the tower plate to the
heat
exchanger for heat exchange of untreated detergent oil. In the atmospheric
tower,
13
CA 02707573 2012-08-14
many tower plates are installed for the purpose of heat transfer and medium
transfer
during dehydration and provision of contact of gas and liquid. The tower plate
makes
the evenness of flow from above to below, increases the contact area of steam
and
liquid, lengthens the time of flow, fully removes the water in the crude oil.
After the
atmospheric tower and heat exchanger, the detergent oil' s temperature falls
to
about 80 C and its water-bearing rate falls to about 5%. The next step is to
realize
the full dehydration after vacuum tower.
After the detergent oil is dewatered in the atmospheric tower and the heat
exchange is made in the heat exchanger, its pressure keeps between 0.2-0.3MPa.
After it is delivered to the vacuum tower by the oil pump, the pressure is
reduced till
full dehydration in principle that the boiling point reduces when the pressure
of the
liquid is lower than under atmospheric conditions. At the top of the vacuum
tower,
the vacuum compressor is installed for suction to keep the vacuum of the flash
tower
at about 20-70kPa. After the detergent oil at a temperature of 80 C enters to
the
vacuum tower, the oil will boil immediately under vacuum of the tower, and the
water
molecule is gasified to be the water vapor and it is suctioned to the vacuum
tower by
the vacuum compressor at the top of the tower. The pressure increases to 0.2-
0.3MPa by the compressor, then it is condensed to the water at a temperature
of 40
t by the condenser, and it is delivered to the water storage tank for further
purification. For that the vacuum dehydration tower works under vacuum, the
tower
bottom is uplifted to the proper height so that the crude oil at the tower
bottom is
pumped out by the oil pump successfully. The oil pump is located at the tower
bottom as close as possible, to lower the resistance loss of source pipes. The
position difference between the tower bottom liquid level and pump entry
depends on
the vacuum, generally 5-10m. The temperature of international crude oil after
full
14
CA 02707573 2012-08-14
dehydration in the vacuum tower falls to 60 C-70 C. It is directly delivered
to the oil
tank for storage without heat exchange.
The cleaned water has the water-bearing rate less than 0.2% after the
dehydration by the said atmospheric and vacuum dehydration system. It can be
directly transferred to the refinery until all indicators after test fully
meet the
standards of the international crude oil.
3. Sewage purification
A little sump oil and some suspended impurities are contained in the
sewage that sump oil decomposition produces, and in the condensation water
that
detergent oil under the normal/reduced pressure produces. Such a sewage will
directly pollute water source and stratum if it is discharged or flooded
underground.
So it must be clarified to reach the standard.
For this invention, the sewage concerned is input to vertical oil removal
tank. With gravity separation method, oil and water are separated by their
density
difference. The sewage in the tank stays for 3 hours, with dropping flow rate
0.5-
0.8mm / s, inflow water oil content1000mg / L, effluent oil content less than
200mg /
L, and oil removal efficiency 80%. For inflow suspended matter 300mg / L,
effluent
suspended matter is less than 240mg / L, and suspension removal rate of 20%.
In
this way, the sewage with larger particles and floating sewage after being
stilled, so
that continuous phase oil slick can surface. When surface oil is thick,
suction pump
can be applied to transfer it to sewage tank for re-purification. The sediment
is
drained to kettle by outlet at bottom of the tank for chemical thermal washing
with
aqueous alkali, solidified with other sewage at last.
The sewage being purified by vertical tank has very low oil content rate
and impurity rate, so it's not necessary to gradually clarify it with other
complicated
CA 02707573 2012-08-14
methods. Filtering it in oil-water filter can completely remove the sewage and
all
impurity in water, so that the sewage can reach national standard for purified
water.
HF-E01 oil filter is selected, consisted by filtering tank of thick and thin
two
levels based on coagulation dynamics and micro-vortex principles. Pressurized
by lift
pump, the sewage enters thick filtration tank for oil removal. The treated
sewage
flows in micro-suspension enclosure for purification with micro-vortex, then
in ring
space for gravity settling and slag separation. After that, the water flows in
filter
cartridge sidewise, with fine particle and oil droplets retained by filter
medium
nutshell. The designed removal rate for oil and suspension is more than 80%.
The
sump oil separated outflows from upper oil tube, and impurities are discharged
from
lower blow-off pipe. Being filtered, the water is drained from center outlet
pipework.
Flowing in, filtering and discharging is operated simultaneously. For
conventional
wastewater or sewage, washing desorption can achieve the same desired effect.
This device carries the advantage of water treatment equipments in domestic
and
abroad, integrating vortex coagulation separation with micro vortex
decontamination,
levitated sphere oil removing, walnut shell filtration and purification,
filtering media
filling by pump, and cycle medium washing and regeneration etc. The device is
multifunctional and multi-level, separating oil and water while isolating
liquid and
solid, featured by high capacity, high filtration precision, continuous
discharge of
sewage and oil, easy regeneration, simple operation, and safe reliable running
etc.
For detailed data, see Table 3. Being tested, the sewage filtered by this
device
completely complies with the standard specified in Recommended Indicators and
Analysis Methods for Water Quality of Clastic Rocks Oil Deposit SY-T5329-94,
and
GB8978-88 national comprehensive standard on exterior drainage. Standardized,
the water can be directly discharged or flooded underground.
16
CA 02707573 2012-08-14
4. Sludge solidification
Sediment impurities from the said process contain about 15% crude oil
through the chemical laboratory analysis, which is separated with the chemical
thermal washing method. This method can decrease oil residual rate to less
than
0.5%. The recycled alkali can be used repeatedly, conforming to national
environmental requirement.
Being analyzed, the sludge chemically washed contains less than 0.5%
residual oil, and about 40% water. The mineral components of the sludge: 95%
calcite, 1% anhydrite, 1 /0 quartz, 2% rock salt and 1% potash feldspar.
Measured by
wet sieving device, the grain diameter of mud particle is between180-200
meshes.
For this invention, cement based solidifying, quicklime and alumina coagulant
aid
method can be applied to make final consolidation. 425#common silicate cement
whose ingredients are dicalcium silicate and tricalcium silicate is appled in
the curing
agent to make a hydration reaction after mixing with sludge to form hydraulic
materials, mainly including tobermorite and ettringite, to be up to the effect
of sludge
consolidation. At the same time, hydration products can stabilize and seal
pollutants
to reduce environment pollution. Coagulant aid contains calcined lime and
alumina,
which have hydration reaction with cement during consolidation process, reduce
cement volume, promote coagulation, enhance intensity of curing block, and
increase the absorption of harmful substances. Quicklime and alumina produce
hydration reaction with cement, generating calcium hydroxide, aluminum
hydroxide
and other non-water-soluble substances that can absorb and precipitate a large
number of heavy metals and other toxic hazardous substances and reduce
leaching
rate of hazardous substances so as to detoxify. Quick lime can also be used to
sterilize for sludge for better hazard-free treatment.
17
CA 02707573 2012-08-14
For the new method of final solidification treatment, cement-based
solidification, quick lime and alumina coagulant aid have the following
advantages: (1)
during sludge treatment process, less curing agent and coagulant aid is used
for
better solidification effect, lowering sludge volume after solidified,
sterilize pathogenic
bacteria and parasite (ovum) in sludge; (2) being solidified, it can avoid the
loss of
harmful substance in heavy metals to prevent secondary pollution; (3) the
solidified
sludge changes mobility, with low volume, high compression resisting strength
and
immersion resisting capability, and lower leaching toxicity, maintaining solid
formation and stable chemical properties for long-term, keeping good stability
after
being soaked in water, acid and alkali while the heavy metals in sludge will
be
reserved to weaken mosquitoes-prone environment; (4) the solidified sludge can
be
used as road material, building materials, or landfill cover soil, which
improves its
economic value and realizes resource utilization.
The beneficial effects of this invention are as follows:
1. The waste oil and acid oil centralized processing solves the problem of
difficult separation of oil, water and impurities in waste oil and acid oil.
After the
centralized processing, there is no sewage, sludge and sewage oil discharge,
which
substantially reduces the pollution to surrounding environment and corrosion
to
equipment. Oil tank is kept clean for long-term, without being desilted, which
reduces
the expense on cleaning and staffing.
2. The centralized processing turns waste into wealth, recycling a large
number of crude oil, reducing production cost of crude oil. The solidified
sludge can
also be directly used as building materials.
3. The invention greatly enhances economic benefits of oil field. The waste
oil and acid oil being processed reaches national standard. The recycled GB
crude
18
CA 02707573 2012-08-14
oil account for more than 70% of waste oil. By current list price of GB crude
oil, it can
increase income for tens of millions Yuan each year, and enhance crude oil
production.
Other advantages, objectives and features of this invention will be
explained in the following specifications to some extent, which are obvious
for the
technical staff in this domain based on the following study, or presented in
the
practice of this invention. The object and other advantages of this product
can be
realized and obtained by the following instruction book, claim of right and
the
structure specially pointed out in figure.
BRIEF DESCRIPTION OF THE DRAWINGS
For better presentation on invention's purpose, technical program and
benefits, further detailed description will be made with the figures, in
which:
Figure 1 Flow chart for sump oil and acid oil processing.
Figure 2 Flow chart for oil purification and atmospheric and vacuum
dehydration.
Figure 3 Flow chart for sewage purification processing.
Figure 4 Flow chart for atmospheric and vacuum dehydration system.
DETAILED DESCRIPTION OF THE INVENTION
With the following figures, the preference examples are described in detail.
Example 1
X-ray diffractometer analyzes that in the waste oil and acid oil of Jidong
Oilfield, the content of large particle impurity is about 1% -2%. Fine
sediment and
other impurities account for about 15% -20%, water content 50% -60%, and pure
oil
20-30%. Basket-type filter is used to initially filter sediment impurities of
larger
volume. The waste oil filtered is poured into kettle for separation of silt,
oil and water.
19
CA 02707573 2012-08-14
Compressed air is injected from the coiler of hole diameter 80pm at the bottom
of
kettle, generating fine bubble of diameter about 80pm for mixture. Add 10%
thickness sodium carbonate solution in waste oil to stabilize PH value at 7.2,
then
put in PR-02 demulsifier of 0.6% of waste oil volume in the tank, and
flocculant PFS
to react continuously. The lasting time of injecting compressed air is 3
hours. Then
stop injecting, still to precipitate for 5 hours, input the purification oil
at upper kettle to
purification tank, the sewage at middle is discharged in caustic tank while
upper
sludge is left in kettle.
Example 2
Basket-type filter is used to initially filter sediment impurities with a
larger
volume. The waste oil filtered is poured into kettle by "HF-B01-LCR lobe oil
pump.
When the oil in kettle is heated to 60 C, compressed air is injected from the
coiler of
hole diameter 90 ft m at the bottom of kettle, generating fine bubble of
diameter
about 90 gr m for mixture. Add 15% thickness sodium carbonate solution in
waste oil
to stabilize PH value at 7.5. When the temperature in kettle is increased to
80 C, add
PR-02 demulsifier of 0.7% of waste oil volume in the kettle, and HF-02 type
flocculant of 0.4% of waste oil volume in the kettle. The lasting time of
injecting
compressed air is 3.5 hours. Then stop injecting, still to precipitate for 6
hours, input
the purification oil at upper kettle to purification tank, the sewage at
middle is
discharged in caustic tank while upper sludge is left in kettle.
Table 1 Specifications of HF-01 demulsifier
No. Item HF-01A HF-01B --
1 Appearance Yellow or light yellow viscous liquid
2 Hydroxyl value 45 -56 56
CA 02707573 2012-08-14
[mgkoH/g]5
3 Crystallization point [t] -15--25 -18--22
4 Chroma No.5 800 1000
Table 2 Specific indicators of HF-02 flocculant
Name Index
Appearance Light gray liquid
Relative density ( 20 C ) g/cm3 ?.1.19
Alumina% 10.0
Basicity% 50.0 -85.0
PH value (1% aqueous solution) 3.5 - 5.0
Water insoluble matter% 50.5
Example 3
Basket-type filter is used to filter waste oil. The waste oil filtered is
poured
into kettle by "HF-B01-LCR lobe oil pump. When the oil in kettle is heated to
50 C,
compressed air is injected from the coiler of hole diameter 60,u m at the
bottom of
kettle, generating fine bubble of diameter about 60,u m for mixture. Add 7%
thickness sodium carbonate solution in waste oil with HF-B02-IMC stainless
steel
magnetic clutch to stabilize PH value at 6Ø When the temperature in kettle
is
increased to 70 C, add HF-01B demulsifier of 0.8% of waste oil volume in the
kettle,
and HF-02 type flocculant of 0.2% of waste oil volume in the kettle. The
lasting time
21
CA 02707573 2012-08-14
of injecting compressed air is 2.5 hours. Then stop injecting, still to
precipitate for 6
hours, input the purification oil at upper kettle to purification tank, the
sewage at
middle is discharged in caustic tank while upper sludge is left in kettle.
Example 4
The implementation method is basically the same with Example 1. The
difference is that the purified oil in the tank is filtered by HF-001 bag-type
fine filter of
bore diameter 1000 g m, heated to 120 C, dehydrated in the dehydration tower,
heated to 80 C by heat exchanger, put in the vacuum dehydration tower to be
dehydrated at 70kPa for GB crude oil. The water vapor extracted from the said
atmospheric/vacuum dehydration tower forms sewage after condensed, and then
enters the sewage tank.
Example 5
The implementation method is basically the same with Example 1. The
difference is that the sewage in the tank is discharged in vertical natural
oil removal
tank, with falling speed 0.7mm / s. Being filtered by HF-E01 oil filter, the
effluent is
used for underground flooding.
Table 3 Specific data for HF-E01 oil filter
Item Index
Capacity (m3/h) 60
Working pressure(MPa) 51.0
Operating temperature ( ) 580
Filtration rate(m/h) ?_40
Backwash cycle(h) ?..24
Backwashing strength(l/s=m2) 54.0
22
CA 02707573 2012-08-14
Backwash water(m3/m2.d) 53.0
Content of influent suspension (mg/L) 530
Content of influent oil(mg/L) 560
Content of suspension filtered(mg/L) 52
Content of oil filtered(mg/L) 510
Particle volume of diameter less than >85%
2pm after filtration
Being tested, the sewage filtered by this device completely complies with
the standard specified in recommended indicators and analysis methods for
water
quality of clastic rocks oil deposit SY-T5329-94, and GB8978-88 national
comprehensive standard on exterior drainage. Standardized, the water can be
directly discharged.
Example 6
The implementation method is basically the same with Example 1. The
difference is that the 15% sodium hydroxide aqueous solution at 70 t is washed
for
20min by solid-to-liquid ratio 2:1, and then precipitated for 3 hours. The
clarified oil
washed from upper surface is put in clarified oil tank. The alkali liquor at
middle-level
is recycled in alkali tank. Silt impurities at the bottom of kettle are
transferred in mud
solidifying pool with mud pump.
Example 7
The implementation method is basically the same with Example 6. The
difference is that based on the mud weight in solidifying pool, add 8%
silicate cement,
3% quick lime and 1% alumina, which is mixed evenly with mechanical mixer and
23
CA 02707573 2012-08-14
maintained for 15 days to form the solidified sludge of compressive strength
4380KN/m2 for road construction and building materials.
For reference to some optimized examples clearly specified in this
invention, the ordinary technicians in this field should understand that it
can be
changed in various forms and details, without deviating from the spirit and
scope
defined by claim of right.
24
