CN101113041A

CN101113041A - Sewage purification method for oil production

Info

Publication number: CN101113041A
Application number: CNA2006100294528A
Authority: CN
Inventors: 翁天波
Original assignee: Shanghai CNPC Enterprise Group Co Ltd
Current assignee: Shanghai CNPC Enterprise Group Co Ltd
Priority date: 2006-07-27
Filing date: 2006-07-27
Publication date: 2008-01-30

Abstract

The invention relates to a purification and treatment technique field for polluted air. The oil extraction wastewater purification method of the invention is that: activated magnesia oxide 50 to 500mg/L is directly added to pretreated thick oil wastewater (oil content lower than 30mg/L, suspension lower than 1000mg/L); the mixture enters into an eddy reactor, after mixing and reaction for 1 to 15 minutes, inorganic aluminum salt and organic flocculating agent are added to water out and then enter into a sludge reactor; the sludge reactor generates return sludge by 1 to 6 times of the water in through top return pump or a lifting and stirring device, the return sludge fully mixes with water in for 10 to 60 minutes and comes into a clarification and precipitation device; after 30 to 90 minutes of clarification and precipitation, silicon dioxide and suspensions are removed, and the water out enters into the next stage treatment device, sludge is discharged from a sludge groove, thus reaching the target of silicon removing and water purification.

Description

Sewage purification method for oil production

Technical field

The present invention relates to the oilfield sewage purification treatment technology field after recovering the oil in a kind of oil field.

Background technology

Contain a large amount of sewage (10 90%) in the oil field mining liquid, become oil field extracted water behind these sewage and the crude separation.Viscous crude field recovered water (being condensed oil sewage) generally is back to use injection boiler after advanced treatment.Sewage after the advanced treatment requires dioxide-containing silica below 50mg/L.At present, normally at first (oil-containing is lower than 16m//L to the technology of condensed oil sewage processing silicon-dioxide with pretreated sewage, suspended substance is lower than 30mg/L) adjust pH value to 10.2-10.5, add magnesium oxide or magnesium chloride then, after settling pond or the clarification of settling tank precipitation, remove the silicon-dioxide in the sewage.Regulate PH and generally use calcium oxide or sodium hydroxide.Should remove silicon technology and mainly have following shortcoming: (one) handles back sewage and is in unsteady state, and very easily fouling in case control badly, will make aftertreatment device move; (2) this process stream amount is big, one one side needs to drop into a large amount of PH and adjusts agent, desiliconizing agent (dosage is 15 times of removal silicon-dioxide), flocculation agent (total amount is at 1000 2000mg/L), (dosage is big more for a large amount of body refuse of post precipitation generation on the other hand, body refuse output is big more, be generally dosage 80%), bring very big difficulty to operational management; (3) be somebody's turn to do: the art breading medicament expense is higher, and one is generally 30% of running cost; (4) this technology is strict to the condensed oil sewage pre-treatment.Based on above reason, present removing silicon from thick oil sewage system is difficult to operation, has seriously restricted the development of condensed oil sewage advanced treatment and reclamation technology, and it is together ancient to influence further carrying of field produces, economic benefit.

Summary of the invention

The object of the present invention is to provide a kind of treatment effect good, the sewage purification method for oil production that cost is low.

The present invention is achieved in that

A kind of sewage purification method for oil production, this method is: directly to add activated magnesia 50-500mg/L in pretreated condensed oil sewage (oil-containing is lower than 30mg/L, and suspended substance is lower than in 1000mg/L); After entering Vortex reactor, through 1-15 minute hybrid reaction, water outlet entered sewage sludge reactor after adding inorganic aluminate and organic floculant; Sewage sludge reactor utilizes reflux pump or promotes the sludge back flow quantity that whipping appts produces 1-6 times of flooding quantity, enters the clarification settling vessel after 10-60 minute with the water inlet thorough mixing; After precipitation clarification in 30-90 minute, silicon-dioxide and suspended substance are removed, and water outlet enters the next stage treatment unit, and mud is discharged by sludge sump, thereby reaches the purpose of silica removal water purification.

Advantage of the present invention is:

(1) owing to need not to regulate pH value in present method, during handling, silica removal reaches the equal non-scaling of sewage after handling;

(2) the activated magnesia dosage is little, only for the 1-3 that removes silicon-dioxide doubly, flocculation agent to add dose also very low, silica removal process dosing total amount only is 100-500mg/L, the sediment weight of generation is 80% of a dosage;

(3) cost of silica removal process reduces (medicament expense and sludge dewatering cost descend) greatly, only is the 10-15% of total cost;

(4) pre-treatment of condensed oil sewage requirement is lower before the silica removal, only require the oil-containing in the sewage is reduced to below the 30mg/L, and to the suspended substance no requirement (NR);

(5) silica removal process and water purification process can be carried out simultaneously, and its water outlet dioxide-containing silica can drop to below the 50mg/L, increases as dosage, silicon-dioxide removes rate to be increased, the minimum 1mg/L that drops to, suspended substance can drop to below the 5mg/L through post precipitation, for subsequent disposal provides good condition;

(6) silicon and water purification separate treatment fall in traditional technology, produce two kinds of mud in the system, i.e. oily sludge and remove silicon sludge, and this processing method silica removal and water purification carry out simultaneously, only produce a kind of mud, help the subsequent disposal of mud.This method technical process is simple, easy handling, and running cost is low, and it is integrated to have realized removing silica purge, and treatment effect is good, handles back sewage non-scaling, can be widely used in the silica removal water purification process in the oil-field thick-oil advanced treatment of wastewater.

Embodiment

Further describe the present invention by the following examples.Below in conjunction with accompanying drawing the invention process is illustrated.

Technical process of the present invention, be following the finishing of silica removal water purification working process: in the pre-treatment condensed oil sewage, adding the activated magnesia that content is 50-500mg/L (dosage is 1-3 times of the removal silica volume), this activated magnesia makes for calcining, can make 80～500 order fine particles with very strong adsorptivity as required; Add the activated magnesia short mix in Vortex reactor 1 that has in comparatively high temps (40-70 ℃) sewage, be uniformly distributed in the sewage, the reaction of magnesium oxide particle surface oxidation magnesium molecule and water generates magnesium hydroxide, the colloidal silica that exists with various forms in the magnesium hydroxide planar water under suitable temperature; Enter sewage sludge reactor add inorganic aluminate and organic floculant in finishing this reacted sewage after, inorganic aluminate (or other inorganic water purification agents) add-on is that 5-50mg/L (optimal coagulant dose 1 5mg/L) organic floculant add-on is 0.1-1mg/L (best 0.5mg/L); The returned sluge that inorganic aluminate and organic floculant and 1-6 doubly flow to the water yield reacts jointly, and the concentration of mud can be controlled by the flow velocity that mixing liquid in the mud quantity of reflux control sewage sludge reactor that stirs the generation of lifting gear or reflux pump rises in the reactor; Fully the sewage of reaction enters the precipitation settler after forming bigger flco, after operation for some time (2-5 days), form the sludge suspension layer in the precipitation settler, it is held back entering flco in the sewage, filteration, obtain clarification by sewage behind the sludge suspension layer, mud increases gradually along with the flco of holding back and thickens, and above behind the 50cm of sludge sump top, is discharged by sludge sump.

Claims

1. sewage purification method for oil production, this method is: directly to add activated magnesia 50-500mg/L in pretreated condensed oil sewage (oil-containing is lower than 30mg/L, and suspended substance is lower than in 1000mg/L); After entering Vortex reactor, through 1-15 minute hybrid reaction, water outlet entered sewage sludge reactor after adding inorganic aluminate and organic floculant; Sewage sludge reactor utilizes reflux pump or promotes the sludge back flow quantity that whipping appts produces 1-6 times of flooding quantity, enters the clarification settling vessel after 10-60 minute with the water inlet thorough mixing; After precipitation clarification in 30-90 minute, silicon-dioxide and suspended substance are removed, and water outlet enters the next stage treatment unit, and mud is discharged by sludge sump, thereby reaches the purpose of silica removal water purification.