Oil treatment units – ‘Heater – treater’ type
PURPOSE The modular automatic oil treatment unit (UPN) is designed for effective oil heating, degassing, dehydration and desalting of emulsified crude oil to produce tank oil.
At present, oil treatment to transportation and further use, as a rule, is realized by two methods - using of expensive equipment set consisting of oil emulsion heating furnace, demulsificator, separator, oil demineralization system or via the imported combined "Heater-Treater" type units.
Being based on positive operation experience of the "Heater-Treater" type units in Russia, the "Generation" experts within the framework of realization of the import substitution program have designed the UPN complex oil treatment unit with additional desalting section that by its performance and functionality is highly competitive with production of leading world manufacturers.
ADVANTAGES OF UPN UNITS
The up-to-date technology solutions used in the unit design allow to minimize unit dimensions and, thus, their steel intensity, and to combine several technology flows and to increase oil treatment quality.
The cost efficiency of application of UPN produced by the "Generation" Industrial Group is stipulated by the following factors:
- simplification of oil treatment process flowsheet;
- energy-saving;
- decrease of costs of object construction (lower size of site, etc.);
- reduction of maintenance staff;
- reduction of labor expenditures of operations on workflow information acquisition and transfer.
Technical data
| PARAMETER | UPN - 250 | UPN -500 | UPN -1000 | UPN -3000 | ||
| Oil emulsion output, kg/s (t/day) in the range |
1,4-2,89 (125-250) | 2,8-5,78 (250-500) | 2,8-5,78 (250-500) | 2,8-5,78 (250-500) | ||
| Oil emulsion pressure, MPa, max. |
0,6 | |||||
| Water content in oil emulsion, % mass., max. | 30 | |||||
| Oil viscosity at 20 °Ñ, m2 /s (cSt), max. | 50 õ 10-6(50) | |||||
| Oil emulsion heating temperature,°Ñ, max. |
80 |
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| Mass quantity of water at unit outlet, %, max. | 0.5 | |||||
| Chlorous salt concentration at unit outlet, mg/dm3, max. | 100 | |||||
| Weight of unit, kg, max. | 12 000 | 20 000 | 35 000 | 50 000 | ||
| Fuel | Natural or oil-well gas with hydrogen sulfide content max. 0,002 % mass | |||||
| Fuel gas pressure at unit inlet, MPa, in the range |
0,3 - 0,6 |
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| Gas flow (at combustion value 33500 J/nm3) nm3/h, max. | 45 | 85 | 170 | 510 | ||
| Unit (heat) efficiency, %, min. | 80 |
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| Unit weight, max., tons |
12 | 20 | 35 | 50 | ||
STRUCTURE AND OPERATION OF UPN UNIT
UPN consists of: technological unit, adjustment unit, preheater for oil emulsion and soft water, as well as of automation facilities providing effective control of workflows and main parameters monitoring.
- The technological unit consists of coalescence section, oil and sweet water intermixing unit, desalting and final settling sections. The internal surface of a vessel is protected from corrosion by the special corrosion-resistant coating providing long and reliable service life of the unit. Oil stream flows in horizontal direction. This method is op-timal for oil treatment; it assists to pendular configuration and water separation within the unit.
- Heating and coalescence section is designed either as single horizontal fire tube or as double vertical fire tubes, depending on the unit capacity. Fire tubes placed in emulsion medium are of special U-shape having the designed heating area. Burner with flame arrester is connected to the fire tube end. Burner is ignited by pushing of “ignition” button, spark ignition panel is turned on; after 5 to 10 minutes at the gas feeding line shutoff valve is opened; graphic display at control panel provides corresponding indication. When the flame appeared, a command to open control valve at gas line to burner comes. Assist gas coming from the unit is used as fuel. Having passed through control valve and flow meter, gas is fed to separator where it is separated from free water, and then it flows to heating coil. Heating of gas prevents condensation in combustion pipeline. In order to prevent heat tubes burnout their walls are equipped with thermocouples, signaling in the case of overheating and consequently shut off the valve at fuel gas inlet to the burner.
- Through the baffle valve, regulating fluid flow and the input connection an oil emulsion is fed to settling sec-tion of the unit where it is spread along a section of the unit and comes to coalescing head, where the emulsion is separated to oil and water. According to the results of calculations, a space between plates in coalescing head is accepted to be 15 mm. At that, more than 90 % of drops of 35 microns in diameter and more than 50 % of drops of 25 microns in diameter will be settled. The level of oil as well as the level of "water-oil" phase separation are automatically controlled and measured by means of level sensors transmitting a signal to input valve and to water discharge valve respectively. In addition, gas separated during process is forwarded upwards to gas section.
- Passing through the heat tubes section partially dehydrated oil is fed to coalescence section. It consists of few coalescence modules. Calculations for these blocks - sections, their number and sizes depend on operating conditions of the unit and a physic-chemical composition of processable oil. Apertures of grids through which oil passes, increase Reynolds number that promotes coalescence of water drops. Coalescence grids of this type are extremely practical and effective for use; they prevent oil contamination with sand, settlements and asphaltenes. After coalescence, oil overflows through the baffle board to desalting section.
- Desalting section consists of special chutes and water-distributing system, including feeding collector and distribution nozzles. Oil flows down by chutes; preheated fresh water is fed to collector and then is injected and mixed with oil. The oil level and level of "oil - water" phase in this section of the unit is measured and controlled using level indicators sending a signal to respective valves. The "oil - water" interface is below the distributive pipeline to the sec-tion of final coalescence and oil withdrawal.
- Oil and desalting water residuals are fed through distribution network up to the section of final coalescence and oil separation pressure due to the vessel pressure and pumps for oil pumping-out. Oil is fed upstream through special coalescence block and oil collector to vessel outlet. Coalescence block of special design separates water residuals from oil. Oil level is controlled via level sensor. When the preset oil level exceeded the pumps for oil pumping-out are turned on. Oil flow is measured by a flow meter. In the desalting section, there are sample thieves for sampling fluids from different levels to analyze purity of output products.
- System of cleaning from sand and mechanical impurities. At oil treatment, a significant amount of sand and other mechanical impurities settles in a vessel. The system provides hand-operated periodic cleaning without termination of process. Water under high pressure is released from the line of injection nozzles in pipes located longwise of the unit. The water jet cuts sand deposits and retains it in suspension that at bleeder valves opening enters to the special sand collectors.
- Control block. It measures and controls the flow of oil emulsion. It is designed as heat insulated room placed on heat-insulated basement. The block includes the following: emulsified oil intake line, oil discharge line, water discharge line, sampler tank, fan, electric heater, fire alarms, gas detectors and drainage pipeline for remote vessels.
- Fuel treatment block. The block of fuel preparation is designed as heat-insulated cabinet with glazed doors and the gas inlet pipe from processing block, gas inlet from foreign source, gas outlet from units, gas outlet to main and ignition burners, gas outlet to spark-plug. Fuel gas comes to treatment block from processing block or foreign source, it is filtered; regulating valve controls its pressure and flow rate depending on temperature value of oil emulsion in processing block. Fuel gas is fed to burners through successively installed solenoid valves.
- The UPN oil treatment unit is equipped with automatic control system providing remote and local control and parameters changes, automatic regulation and emergency protection functions.
MAIN FUNCTIONS OF AUTOMATIC CONTROL SYSTEM
- Automatic control of process variables, including:
- measurement and control of oil emulsion temperature in the PPT-0,2G preheater;
- measurement and control of pressure in the unit;
- measurement and control of fluid flow (well production) at the unit inlet;
- measurement and control of oil level in tank;
- measurement and control of “water-oil” interface level in preliminary water discharge section (heating sec-tion);
- measurement and control of “water-oil” interface level in oil desalting section;
- control of fuel gas pressure at general gas input line to burners (ahead of main fire stop);
- control of fuel gas pressure to primer burner. - Measurement and control of process parameters:
- oil consumption at unit outlet;
- gas consumption at unit outlet;
- oil-field water consumption at unit outlet;
- sweet water consumption for oil desalting;
- valve regulators position;
- fuel gas pressure at main burner inlet;
- fuel gas pressure at primer burner inlet;
- fuel gas pressure in gas separator;
- liquid pressure at the unit inlet; - Automatic logging of events and emergency messages;
- Emergency protection of oil treatment unit;
- Warning and alarm signaling if process parameters exceed the limits.
- local visual control of main process parameters;
- automatic putting of the unit to preset operation mode (bleeding, control of draft in firebox, ignition of primer and main burners, putting into the operation mode);
- automatic keeping of set operating practices of the unit;
- scheduled automatic shutdown of the unit;
- automatic emergency shutdown and locking of the unit start-up program with sound and light signaling at exceeding of set values of the main process parameters:
- increase of gas content in the rooms of the unit technological blocks;
- emulsion pressure increase at the unit inlet;
- lowering of intermediate heat carrier level in preheater;
- decrease of exhaustion in a stack;
- reduction of fuel gas pressure ahead of burners;
- fuel gas pressure increase ahead of burners;
- flame going-out in firebox;
- rise of temperature of emulsion heating;
- decrease of heated product consumption;
- rise of temperature of outgoing combustion gases;
- failures of flame controlling channel;
- electric power switch-off.
- technological module;
- adjusting module;
- fuel treatment module;
- burners;
- smoke stacks;
- service platforms;
- ladder;
- automation systems;
Process of fuel gas combustion in preheater provides the minimum content of carbonic oxide and nitric oxides, according to the GOST 21204 and GOST Ð50591 requirements.
OIL TREATMENT UNITS WITH REMOTE HEATER
Purpose
Oil treatment unit with remote preheater is designed for heating, dehydration and desalting of emulsified crude oil to produce tank oil. Our specialists had designed the UPN system equipped with remote heater that uses intermediate heat carrier for oil heating. Water, antifreeze or other medium can be used as intermediate heat carrier depending climate conditions of the unit location.
Depending on the output required the unit ca be equipped with heaters of PPT -0,2; PP-0,63; PBT-1,6 types.
The scope of supply of UPN includes:
- technological unit
- adjustment unit
- preheater, depending on UPN output
- ladder and operating floors
- unit automation facilities
Advantages of UPN unit:
- application of autonomous oil heater with intermediate heat carrier increases safety, reliability and service life during oil treatment process;
- application of special coalescence sections increases efficiency of destruction and separation of products coming for oil treatment;
- application of mixing device, which has special construction of desalting sections, increases quality of oil washing from mineral salts;
- application of devices for cleaning technological unit from sand and mechanical impurities;
- UPN equipped with instrumentation of modern industrial control, which providing: control of technological process; increased reliability and equipment safety operation; personnel comfortable working; efficiency of information gathering. This can be reached thanks to application of up-to-date technical and software controls, reliable sensors and actuators.
