O I L M A S T E R - 2 1

Function principles of the plant for separation of Emulsions respectively disolved light-weight hydrocarbons and their aromatics.

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Contents: Page: 25

Coversheet 1

Contents 2

Introduction 3

Function Principles 5

1. Skid and Container 5 30

2. Flow and Separation 5

3. Flow and Rectification 6 (New design of Vacuumrectification requested to be patented)

4. Flow and UV-Oxidation 10 35

5. The Aliphatic-Measuring Device 11

6. The Aromatic-Measuring Device 11

7. The Centerline Equipment 12

Drawings (System and Components) : Number:

Skid with Container (side view) 1 40

Flow-Diagram 2

Flow-/Blockdiagram 3

Arrangement of Components and Skid-Mounting- plates 4

Arrangement of Components, Piping 5 45

General view Rectification-column 6

1. Head of Rectific. -/Fractionating column 7

2. Center-top " " " 8

3. Lower Section " " " 9

4. Sump " " " " 10 50

5. Trays " " " 11 Inductive Conductivity Sensor " " 12 Consistence Measuring Sensor " " 13 Demister " " 14 Heat Exchanger Panels (internal) " " 15 55 Vacuum-pump (dry-running) " " 16-17

5 Introduction:

Until the present, centrifuges are utilized for the separa¬ tion of e ulgated production water on offshore production 6 platforms, operated by the oil and gas industries. Usually the best values attained on the overboard water are 80 ppm. These values are still far above the value required by the government (Dutch sector: 40 ppm.). Also in many cases emul¬ sions are injected back into the sea-bottom (cuttings etc.) 6 or will be otherwise disposed off.

It has to be pointed out, that until today for measurement of the overboard water, oil-in-water monitors were used, working with the scattered light system. These measurements were not very accurate, because of the deviation of the mea- 7 suring lightbeam after encountering solids. A measuring-device, the OMS-40 has been developed working according to the- NEN 6675 mod, which measures oil-in-water only (without solids) . The dutch norm NEN 6675 mod. is an in¬ tensified regulation, to the ger an H 18 to perform the ana- 7 lysis for determination of dissolved lightweight hydrocarbons in water. The accurate measurement respectively analysis was, until the OMS-40 was developed, only possible to perform ma¬ nually. For this analysis the Bo en spectrometer was used in connection with the TE-Netherlands Equipment. Daily flights to 8 the platforms with helicopters had to be performed to take samp¬ les for the laboratory-analysis, and forward the daily reports of the results to the Department of Mining. It is requested, by the Dutch authorities, that samples are to be taken at least 16 times per month. 8

By use of the OILMASTER-2 these daily or special flights for sampling are only required once a month, for calibration. This is based on the fact, that the output signals of the two mea¬ suring devices, for Aromatics and Aliphaticε, are continuously 9 transmitted to the Centerline-platform, where they are displayed on a monitor. The aliphates and the aromates are shown as a cur¬ ve on this monitor. The limit set by the Government (40 ppm.) is shown as a reference line.

For the measuring of the aromatics, a multi-component analysis 9 system has been included for simultaneous and continuous mea¬ surement and monitoring of up to 30 substances contained in gases and fluids. The user can specify which substances he wi¬ shes to monitor and the analysis system can be calibrated to meet his requirements. The system can measure up to 30 media 10 (aromatics) individually and all at the same time' within 0.5 seconds (on-line) .

Both measuring devices are connected with the solenoid con¬ trolled 3-way overboard valve. Should the required ppm. limit be exceeded, this valve will close the over-board discharge 10 automatically and circulate the contaminated water back to the coalesting tank. Furtheron the out-put signals are continuous¬ ly transmitted to the receiving equipment on the Centerline- platform.

1 Each individual satellite-platform will be continuously scan¬ ned by the system. The ppm. curves on the Centerline-monitor are shown for appr. 15 seconds for each satellite. This guaran¬ tees a good control for the OILMASTER-2 installation and opera¬ tion. Here also an alarm will sound-off, as soon the ppm. limit 1 on one of the units will be exceeded and the values will be re¬ corded on a process writer/printer.

Function principles

1. Skid and Container:

The entire plant consist of three insulated sections, oun- 1 ted on a skid. Each section can be removed for repair, main¬ tenance or placed to another location onboard the platform (lack of sufficient space or too much weight or other reasons) The container also can be slightly pressurized or inerted.

2. Flow and Separation 1 The production water flows from the coalesting tank (A) , thru the pipe (1) , the strainer (2) and the retention-valve (RV-6) into the OILMASTER-2 system and through the pipe (3) to the DVZ-honeycomb separator (B) . The DVZ separates the oilphase from the emulgated water and returns the dirty oil through the 1 pipes (4) , (6) and (7) to the dirty oil tank (Kl) . The emulga¬ ted water leaves the separator, through the pipe (51) with a appr. pressure of 1,5 bar and flows via the 3-way solenoid val¬ ve (3MV-1) and the pipe (8) into the skid ounted Emulsiontank (D) . For the operation of the DVZ-separator, water and air are 1 necessary (air 5-7 bar) . The fresh water flows into the separa-

13 tor through the valve (V-1), the pipe (5), the strainer (9) and the retention valve (RV-1) .

The air-supply with 5-7 bar is led through a ball-valve (KV-1) , 14 the pipe (10) , the air-pressure reducing-station (11) and the pneumatic control valve (PV-1) into the DVZ-Separator. The first stage of the OILMASTER-2, the DVZ-Separator, is go¬ verned by a DECKMA OCD-2 oil-in-water monitor (C) . A measuring line is branching off from pipe ( 8), leading into the OCD-2 14 monitor. After the measuring procedure the fluid leaves the OCD-2 monitor through pipe (49) back into the coalesting tank (A) .

Should the showm ppm. value on the OCD-2 monitor exceed the limit of 15 ppm., than the monitor will activate the 3-way- 15 solenoid control valve (3MV-1) in such a way, that the conta¬ minated water will flow through pipe (7) back into the dirty oil tank (K-l) . When the value is less than 15 ppm., then the emulgated water will flow through the valve (3MV-1) and the pipe (8) into the Emulsiontank (D) . By means of pump (Ppe-5) 15 and the pipe (9) the Emulsion flows through the Heatexchanger (L) , via pipe (10) and RV-4 into the rectification-unit (E) , on the side of the rectification-unit inlet at medium height.

3. Flow and Rectification (new design requested to be paten¬ ted) 16

The pipe (10) is welded airtight to the housing of (E) , lea¬ ding than to the center (11) of the inside section and at an angle of 90 deg. down through the perforated plate-trays (12) , to the centeroutlet of the "vessel" (13) . The pipe is welded

1 to the bottom of this vessel (outlet-opening 14) . The perfora¬ ted stage vessel fills out the lower half of the rectifica¬ tion-unit and serves as a waterlock (Inlet 15) , to hold the vacuum in the unit stable.

Leaving this vessel, the emulgated water flows now between 1 the housing of the vessel (13) and the outer mantel of the rectification-unit (16) upward to the top. At the upper end of the vessel, the nozzle-ring (17) has been welded in, where the emulgated feedwater is pressed through the nozzles and sprayed out over the top-section (12) of the perforated pla- 1 tes. Spraying in the emulgated water causes faster vaporiza¬ tion and increases the flow-rate.

By means of electric heater-elements (18) , the emulgated wa¬ ter will be heated-up to the boiling point (at appr.40 deg.C and a vacuum of 55,5 Torr) . 1

It has to be pointed out, that during the separation of light¬ weight hydrocarbon-mixtures all components will be volatile. The steaπphase contains all components that are supposed to be separated, where in general the lighter volatile components will appear in a higher concentration in the steam than in the 1 fluid. In this case the components will be concentrated by a single vaporization, but not separated. This is possible with the counterflow-system rectification. The exchange of the media can be improved by increasing the flow-speed, which causes the laminar sub-surface to be thinner, but the turbulence increases. 1

1 Because most of the aromatics are having a boiling point higher than water (except Benzol etc., with 80,5 deg. C.) attention has to be paid, that the temperature in the rectification-unit stays constant and stable and will not rise above the boiling point of 1 water. In this way only water and Benzol-aromatics will be stea¬ med out, the rest of the aromatics (.Xylol, toluol etc.) will re¬ main in a liquid state, flowing back down through the tunnelpla- te-sections (19) and the perforated plate sections (12), to the sump of the rectification-unit. The sump of the unit will be 2 blown down auto aticly and periodically by means of the solenoid valve (MV-2) and through the pipe (22) . The concentrate pump (Ppe-1) delivers the concentrate fluid to the dirty oil/concen¬ trate tank (K-l) . A density control (23) activates this sole¬ noid-valve (MV-2) and the concentrate-pump (Ppe-1) . The indue- 2 tive conductivity sensor prevents saturation (Chlorides) of the sump by injection of freshwater.

In the upper half of the rectification-unit the vapor is forced through a. hydrocyclon (x) and after this through a condenser (24) where a condensate-collecting basin (25) is located, where the 2 vapor is forced through and condensates. The condenser will be supplied with fresh water through the pipes (26) and (27) . The condensate will be collected in the condensate-collecting-basin (25) and through pipe (28) and the retention-valve (RV-5) pumped out by the condensate pump (Ppe-2) . The condensate pump will be 2 activated by means of floatswitches, (SS-1) located in the con¬ densate collecting-basin.

To the outlet-opening (29) of the condensate-collecting-ba- 2 sin a discharge-pipe (28) is adapted, acting as suction-line of the condensate-pump (Ppe-2) . The suction-line is fitted to the condensate-collecting-basin below the low-position of the condensate (float-switch) , to secure the vacuum. After the pump (Ppe-2) the condensate will flow through pipe (28a) and 2 the heat-exchanger (14) in the lower section of the rectifi¬ cation-unit, into the skid-mounted condensate tank (G) . The condensate will transfer its heat through the heat-exchanger to the entering emulgated water, saving in this way electric energy. 2

Above the condenser a filter-pack (30) has been installed, holding condensate and solids back. The remains of the vapor will be lead around baffle-plates (31) toward the outlet (32) on top-center of the rectification-unit and evacuated through pipe (33) , the condensate-trap (34) and the retention-valve 2 (VRV-1) by means of the dry-running vacuum-pump DP160VH (F) .

For safety-reasons, a contact-manovacuummeter (35) has been installed in the head of the rectification-unit, connected with the electrical heater-elements (18) . Should the vacuum be lost, the heater elements will be automatically switched- 2 off, to avoid increasing steam-pressure. Furtheron a pressure- relief-valve (36) is installed.

To prevent a flooding of the rectification-unit, excessive fluid will be removed through the pipe (37) , the Solenoid- (MV-3) and by means of the DVZ-suction, pumped through pipe (37) back to the DVZ-Separator. The (MV-3) will be acti¬ vated by means of float-switches (38) and (39) , mounted inside the rectification-unit.

To avoid dry-running of the rectification-unit, a freshwater supply has been installed, pipe (40) and the solenoid-valve (MV-4), controlled by floatswitch (38).

To increase the economical efficiency of the unit, heat ex¬ changers (41) have been installed on the inside of the unit, so that if available, also cooling water of generator-sets or turbines can be lead through.

4. Flow and UV-Oxydation

After the skid-mounted condensate-bottom tank (G) , the UV- Oxidation plant (H) has been installed. The condensate will be pumped-out of the tank by means of a magnetic-coupled pump (Ppe-4) , controlled by the floatswitches (42) and (43) mounted inside the bottom-tank (G) and delivered through the UV-Oxida- tion-plant. Here the remaining aromatics will be eliminated.

The Aliphatic-Measuring Device: 2

The OMS-40 Monitor

The OMS-40 Monitor (J) has been connected with the overbord- discharge line (45) by means of a measuring line (47) . This unit is especially designed for analysing oil in water con¬ tents without solids according to the NEN 6675 mod. 2 The OMS-40 has been accepted by the Department of Mining. The monitor is equipped with a printer. The output-signals (ppm.) will be transmitted to the receiving equipment, on the Center-line-platform. The OMS-40 is connected with the 3-way solenoid-valve (3MV-2) . Should the ppm. values exceed the 2 limit of 40 ppm., the solenoid-valve will close the overboard- discharge (45) and recycle the contaminated water back through the pipe (21) by means of the transfer-pump (Ppe-1) to the coa¬ lesting tank (A) onboard the platform.

The Aromatic-Measuring Device: 2

The measuring device (I) has been connected with the over- bord-discharge line (45) by means of a measuring line (46) . This unit is especially designed for analysing aromatic con¬ tents in water. The unit is equipped with a printer. The out¬ put-signals (ppm.) will be transmitted to the receiving equip- 2 ment on the Center-line-platform. The device is connected with the 3-way solenoid-valve (3MV-2) . Should the ppm. values ex¬ ceed the limit of 40 ppm., the solenoid-valve wil close the overboard-discharge (45) and recycle the contaminated water back through the pipe (21) by means of the transfer-pump 2 (Ppe-1) to the coalesting tank (A) onboard the platform.

The Center-line Equipment:

The transmitted signals from the OILMASTER-2 units will be 2 received on the Centerline-equipment and shown on a monitor as described before.

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