CN1436741A

CN1436741A - Pretreatment process of alcoholic gas field sewage

Info

Publication number: CN1436741A
Application number: CN 02103913
Authority: CN
Inventors: 朱天寿; 吴新民; 刘峰; 李泽新
Original assignee: China Petroleum and Natural Gas Co Ltd
Current assignee: China Petroleum and Natural Gas Co Ltd
Priority date: 2002-02-07
Filing date: 2002-02-07
Publication date: 2003-08-20
Anticipated expiration: 2022-02-07
Also published as: CN1171811C

Abstract

The pre-treatment process of alcohol-containing gas field sewage with high degree of mineralization, low pH value and high impurity content includes filtering in strainer, solid-liquid separation, adding pH regulator NaOH to regulate pH to 7.5-8.5; adding oxidant H2O2 in pipe mixer, adding coagulant 2B for reaction of 0.5 hr, further solid-liquid separation; and adding corrosion and scale inhibitor before the sewage is fed to the methanol recovering unit. After the said pre-treatment process, sewage is treated in the downstream methanol recovering unit, where no precipitate and blocking is produced, the scale inhibiting rate is 95-100% and the corrosion rate to the apparatus pipeline may be controlled below 0.2 mm/a.

Description

Pretreatment process of alcoholic gas field sewage

Technical field

The present invention is used for high salinity, low pH value, the assorted higher pretreatment process of alcoholic gas field sewage of content of machine.

Background technology

At present, technical process is for as shown in Figure 1: alcoholic gas field sewage is through 700m ³The initial gross separation of raw material water tank, through pump pressurization through strainer, interchanger, advance the atmospheric distillation tower, utilize under the normal pressure boiling-point difference of methyl alcohol and water to reach two and be separated the purpose of recovery methyl alcohol.Isolated product methyl alcohol uses as the contrary preparation of individual well station, gas field hydrate, and the sewage that is produced after the Methanol Recovery directly recharges the stratum.

Running condition: because the intrinsic propesties that this Design of device not have to consider to dispose of sewage (be high salinity, low pH value, machine mix content higher), making device regeneration main device rectifying tower often occur in operational process often stops up, the phenomenon that appliance arrangement often is corroded and bores a hole, have a strong impact on the normal operation of device, the ordinary production in gas field is brought certain influence.

Technology contents

The object of the present invention is to provide a kind of sewage containing methanol that on former basis, carries out to handle in earlier stage, enter subsequent technique through the sewage after handling early stage and can avoid the obstruction of equipment, corrosion phenomenon, make normal, the smooth running of device, thereby reduce goods and materials in the production process of device and manpower consumption's pretreatment process of alcoholic gas field sewage significantly.

The present invention is achieved in that

The pH value conditioning agent is NaOH; Regulate sewage 7.5≤PH≤8.5;

H ₂O ₂Add-on: 0.05～0.10ml/L;

Coagulating agent 2B (Poly Dimethyl Diallyl Ammonium Chloride) add-on: 1.0～2.0mg/L;

Corrosion inhibiting and descaling agent is 10.0mg/L by HEDD (hydroxyl phosphate) dosage, and sulfonate dirt dispersion agent dosage is 20.0mg/L, and the azole compounds dosage is that 2.0mg/L forms.

Technical process is as follows:

1. alcoholic gas field sewage tentatively filters through strainer;

2. through topping-up pump 1 raw water is squeezed into 700m ³Raw material water tank carries out solid, liquid to be separated;

3. squeeze into 5m through the sewage after separating through topping-up pump ³Retort;

4. when carrying out for the 3rd step, add NaOH, H to sewage ₂O ₂Carry out combination treatment through line mixer;

5. through 5m ³The sewage of retort adds coagulating agent 2B and enters 700m ³The coagulant precipitation jar further carries out solid, liquid and separates;

6. the sewage after separating is squeezed into the Methanol Recovery unit through topping-up pump 2 with sewage;

7. carrying out in sewage, adding corrosion inhibiting and descaling agent in the 6th step.

Jar sewage that returns after handling through pre-treatment and Methanol Recovery device all reaches national requirements for environmental protection, that is: methyl alcohol≤0.1%, and machine is assorted and contain sodium amount≤5.0mg/L, and total iron ion≤0.5mg/L, scale inhibition performance be 95%～100%, corrosion of carbon steel rate≤0.2mm/a.

Description of drawings

Fig. 1 is process flow sheet in the past;

Fig. 2 is a process flow sheet of the present invention.Concrete enforcement

Long celebrating gas field first purification plant transforms the Methanol Recovery cell process, has carried out the sewage pre-treatment on former technology basis that is:, and this treatment unit comprises 700m ³Storage tank 3 tools, 2 of topping-up pumps, supporting chemicals dosing plant 4 covers have produced various operating parameters thus.

Embodiment 1:

Table 1: variation of water before and after the sewage pre-treatment

	PH value	Ca ²⁺mg/l	?Mg ²⁺mg/l	∑Fe?mg/l	Transmittance
	PH value	Ca ²⁺mg/l	?Mg ²⁺mg/l	∑Fe?mg/l	Transmittance	Before the processing	5.62	?15827.47	?1607.42	?122.36	?17.0
After the processing	8.5	?15778.31	?1371.82	?0.19	?99	Before the processing	5.62	?15827.47	?1607.42	?122.36	?17.0

Embodiment 2

Table 2: variation of water before and after the sewage pre-treatment

	PH value	Ca ²⁺mg/l	?Mg ²⁺mg/l	∑Fe?mg/l	Transmittance
	PH value	Ca ²⁺mg/l	?Mg ²⁺mg/l	∑Fe?mg/l	Transmittance	Before the processing	5.82	?15392.76	?1607.42	?22.36	?17.0
After the processing	8.0	?15097.69	?1580.58	?0.20	?100	Before the processing	5.82	?15392.76	?1607.42	?22.36	?17.0

Embodiment 3

Table 3: variation of water before and after the sewage pre-treatment

	PH value	Ca ²⁺mg/l	?Mg ²⁺mg/l	∑Fe?mg/l	Transmittance
	PH value	Ca ²⁺mg/l	?Mg ²⁺mg/l	∑Fe?mg/l	Transmittance	Before the processing	5.82	?15392.76	?1607.42	?22.36	?17.0
After the processing	8.5	?14881.31	?1371.82	?0.18	?99	Before the processing	5.82	?15392.76	?1607.42	?22.36	?17.0

Data as can be seen from table: sewage is through after the pre-treatment, and the pH value of sewage is significantly improved, Ca ²⁺, M ^G2, ∑ Fe content obviously reduces, the sewage transmittance is almost identical with distilled water.

When handling in Methanol Recovery unit, downstream through pretreated sewage, the nothing precipitation generates in equipment, pipeline, and no latch up phenomenon takes place, and scale inhibition performance is 95～100%, and the corrosion rate of device being distinguished equipment installation can be controlled at below the 0.2mm/a.

Claims

1. pretreatment process of alcoholic gas field sewage, its characterization step is:

1. alcoholic gas field sewage tentatively filters through strainer;

2. through topping-up pump (1) raw water is squeezed into raw material water tank and carry out the solid, liquid separation;

3. it is NaOH that the sewage after separating adds the pH value conditioning agent; Regulate sewage 7.5≤PH≤8.5; And adding oxygenant H ₂O ₂, carry out combination treatment through line mixer;

4. enter retort, and add 1.0～2.0mg/L coagulating agent 2B, reacted 0.5 hour;

5. enter the coagulant precipitation jar then, further carry out solid, liquid and separate;

6. the sewage after separating is squeezed into the Methanol Recovery unit through topping-up pump (2) with sewage, adds corrosion inhibiting and descaling agent simultaneously in sewage.

2. pretreatment process of alcoholic gas field sewage according to claim 1 is characterized in that: H ₂O ₂Add-on is 0.05～0.10ml/L;

3. pretreatment process of alcoholic gas field sewage according to claim 1 is characterized in that: coagulating agent 2B is a Poly Dimethyl Diallyl Ammonium Chloride, and its add-on is 1.0～2.0mg/L;

4. pretreatment process of alcoholic gas field sewage according to claim 1, it is characterized in that: corrosion inhibiting and descaling agent is 10.0mg/L by HEDD (hydroxyl phosphate) dosage, sulfonate dirt dispersion agent dosage is 20.0mg/L, and the azole compounds dosage is that 2.0mg/L forms.