Method for co-producing lithium and bromine by utilizing sulfur-containing gas field water in short process

Abstract

The invention provides a method for co-producing lithium and bromine by using sulfur-containing gas field water in a short process, which comprises the following steps: adjusting the pH value of sulfur-containing gas field water inlet water to be acidic, and then carrying out negative pressure gas stripping treatment on the sulfur-containing gas field water inlet water; pre-filtering is carried out; adjusting the pH value of the pre-filtered effluent to be acidic, and then simultaneously carrying out electrooxidation treatment and gas-liquid separation treatment on the pre-filtered effluent to obtain electrooxidation effluent and bromine-containing gas; adjusting the pH value of the electrooxidation effluent to be neutral or alkaline, and then carrying out post-filtration; and adsorbing lithium ions in the post-filtration effluent by using a lithium adsorbent, and desorbing the lithium adsorbent to obtain a lithium-containing liquid and reinjection effluent. According to the method, impurities such as organic matters, ammonia nitrogen and the like in the gas field water are removed by ingeniously utilizing the electrooxidation effect through the short process of'desulfurization-electrooxidation-filtration ', the influence of the impurities on the subsequent adsorption and lithium extraction performance is reduced, and meanwhile, bromine ion oxidation extraction of the gas field water is realized, so that short-process co-production of lithium and bromine resources of the gas field water is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of gas field water treatment, and specifically relates to a method for short - process co - production of lithium bromide using sulfur - containing gas field water. Background Art

[0002] Lithium bromide is a key mineral resource existing in nature. At present, the industrial bromine extraction technologies mainly include steam distillation method and air blowing method. However, the above - mentioned bromine extraction processes involve the use of hazardous chemical chlorine for oxidation to produce hazardous chemical bromine, which belongs to hazardous chemical production and storage projects and requires relatively strict safety and environmental protection requirements, making it difficult to implement in oil and gas field enterprises. At the same time, due to the addition of various chemicals during the oil and gas field development process, the composition of gas field water is complex, containing a large amount of impurities such as hydrogen sulfide, petroleum, solid suspended particles, organic matter, ammonia nitrogen, etc. Compared with salt lake brine, the existence of these impurities will have an adverse impact on the subsequent extraction efficiency of lithium bromide resources and product purity. However, the current traditional gas field water treatment process does not consider the utilization of resources such as lithium bromide. At the same time, its process involves multiple treatment steps such as "desulfurization - air flotation - advanced oxidation - flocculation sedimentation - filtration", with a large amount of chemical addition, a long treatment process, and a high treatment cost, which will cause additional losses to lithium bromide resources. Summary of the Invention

[0003] To solve the above - mentioned technical problems, the purpose of the present invention is to provide a method for short - process co - production of lithium bromide using sulfur - containing gas field water, so as to shorten the gas field water treatment process and efficiently extract lithium bromide resources.

[0004] To achieve the above - mentioned purpose, the present invention provides a method for short - process co - production of lithium bromide using sulfur - containing gas field water, as Figure 1 shown, which includes the following steps:

[0005] S1. Adjust the pH value of the sulfur - containing gas field water inlet to acidic, and then perform negative - pressure air stripping treatment to obtain negative - pressure desulfurized effluent and hydrogen sulfide tail gas;

[0006] S2. Perform pre - filtration on the negative - pressure desulfurized effluent to obtain pre - filtered effluent;

[0007] S3. Adjust the pH value of the pre - filtered effluent to acidic, and then perform electro - oxidation treatment and gas - liquid separation treatment simultaneously to obtain electro - oxidized effluent and bromine - containing gas;

[0008] S4. Adjust the pH value of the electro - oxidized effluent to neutral or alkaline, and then perform post - filtration to obtain post - filtered effluent;

[0009] S5. Adsorb lithium ions in the post - filtered effluent using a lithium adsorbent to obtain re - injection effluent; then desorb the lithium adsorbent to obtain a lithium - containing liquid.

[0010] The method of the present invention utilizes electro-oxidation to remove organic matter and ammonia nitrogen in gas field water, and simultaneously realizes oxidative extraction of bromide ions, thereby realizing economical and efficient extraction of lithium bromine resources in gas field water in a shorter process, and significantly reducing impurities such as sulfide, petroleum, organic matter and ammonia nitrogen in the gas field water.

[0011] According to a specific embodiment of the present invention, preferably, in S3, the voltage of electro-oxidation is 1.0-3.5V, and the bromide ion content of the electro-oxidation effluent is controlled to be ≤20mg / L.

[0012] According to a specific embodiment of the present invention, preferably, in S3, the pH value of the pre-filtered water is adjusted to 2-6.

[0013] According to a specific embodiment of the present invention, preferably, in S3, the gas-liquid separation treatment method is: introducing gas into the liquid undergoing electro-oxidation to blow out the bromine element generated in the liquid due to electro-oxidation.

[0014] According to a specific embodiment of the present invention, preferably, the gas-liquid ratio during gas-liquid separation is 20-200:1.

[0015] According to a specific embodiment of the present invention, preferably, the gas is air.

[0016] According to a specific embodiment of the present invention, preferably, in S1, the pH value of the influent water of the sulfur-containing gas field is adjusted to 2-6.

[0017] According to a specific embodiment of the present invention, preferably, in the negative pressure gas stripping treatment, the gas is at least one of air, nitrogen and fuel gas, the operating pressure is ≤-30 kPa, and the gas-liquid ratio is ≥10:1.

[0018] Preferably, the hydrogen sulfide tail gas is treated by at least one of alkaline solution absorption, liquid phase oxidation desulfurization, and tail gas incineration.

[0019] According to a specific embodiment of the present invention, preferably, in S2 and S4, the pre-filtration and / or post-filtration method includes one or a combination of two or more of sand filtration, ceramic membrane filtration, and glass filter material filtration.

[0020] According to a specific embodiment of the present invention, preferably, in S4, the pH value of the electro-oxidation effluent is adjusted to 7-13.

[0021] According to a specific embodiment of the present invention, preferably, the pH adjuster includes at least one of hydrochloric acid, nitric acid, sodium hydroxide and potassium hydroxide.

[0022] According to a specific embodiment of the present invention, preferably, in S5, the lithium ion content in the gas field water after adsorption is ≤15 mg / L.

[0023] According to the specific embodiments of the present invention, preferably, the lithium adsorbent includes one or a combination of two or more of aluminum-based adsorbents, manganese-based adsorbents, and titanium-based adsorbents.

[0024] According to the specific embodiments of the present invention, preferably, in S5, the lithium ion concentration in the lithium-containing liquid ≥ 100 mg / L.

[0025] According to the specific embodiments of the present invention, preferably, the desorbing agent used for desorbing the lithium adsorbent includes at least one of neutral soft water, hydrochloric acid, and sulfuric acid.

[0026] According to the specific embodiments of the present invention, preferably, the indicators of the sulfur-containing gas field water inlet include: pH 5 - 8, sulfide 10 - 1000 mg / L, petroleum substances 5 - 200 mg / L, solid suspended matter 5 - 500 mg / L, COD 10 - 5000 mg / L, ammonia nitrogen 10 - 500 mg / L, lithium ions 50 - 500 mg / L, and bromide ions 50 - 3000 mg / L.

[0027] According to the specific embodiments of the present invention, preferably, as Figure 2 shown, the method further includes the following steps:

[0028] Washing the bromine-containing gas obtained in S2 with a chlorine-washing liquid, and then absorbing the free bromine in the bromine-containing gas with a reduction absorption liquid to obtain a bromine product.

[0029] According to the specific embodiments of the present invention, preferably, the reduction absorption liquid is a mixture of sodium hydroxide and urea with a mass ratio of 1:5 - 7, and the obtained bromine product is sodium bromide. The mass ratio of sodium hydroxide to urea is more preferably 1:6. More preferably, when the reduction absorption liquid is close to saturation in absorbing bromine, the density of the saturated liquid is between 1.35 - 1.45 g / cm 3 between, and the saturated liquid is evaporated to dryness to prepare the sodium bromide product.

[0030] According to the specific embodiments of the present invention, preferably, the absorption process of bromine in the bromine-containing gas includes primary absorption and secondary absorption, and a primary absorption liquid (containing sodium bromide) and a secondary absorption liquid (containing sodium bromide) are obtained respectively. More preferably, the bromine-containing gas after chlorine washing is subjected to primary absorption and then continued for secondary adsorption. When the primary absorption liquid is saturated, the secondary absorption liquid is used as the primary absorption liquid and fresh absorption liquid is added as the secondary absorption liquid for continuous cyclic operation.

[0031] According to the specific embodiments of the present invention, preferably, in the chlorine-washing process, the chlorine-washing liquid is one of the sulfur-containing gas field water inlet, the primary absorption liquid, and the secondary absorption liquid; the gas-liquid ratio of the bromine-containing gas to the chlorine-washing liquid is ≤ 1:80.

[0032] According to the specific embodiments of the present invention, preferably, as Figure 2 shown, the method further includes the following steps:

[0033] Perform membrane separation concentration and evaporation concentration on the lithium-containing liquid to obtain a lithium concentrate; then perform resin impurity removal and lithium precipitation on the lithium concentrate to obtain a lithium salt product.

[0034] According to the specific embodiments of the present invention, preferably, the concentration of lithium ions in the lithium concentrate is ≥15 g / L, and the total concentration of divalent metal ions is ≤1000 mg / L. The divalent metal ions include at least one of calcium ions, magnesium ions, barium ions, and strontium ions. The divalent metal ions in the lithium concentrate originate from the metal in the sulfur-containing gas field water. The purpose of controlling the divalent metal ions in the concentrate in the present invention is to prevent them from precipitating out with lithium.

[0035] According to the specific embodiments of the present invention, preferably, the total concentration of divalent metal ions in the lithium concentrate after resin impurity removal is ≤50 mg / L.

[0036] According to the specific embodiments of the present invention, preferably, the method for co-producing lithium bromide with a short process using sulfur-containing gas field water specifically includes the following steps:

[0037] S1. After the gas field water is adjusted to a certain pH by a pH regulator, it enters a negative pressure desulfurization unit for negative pressure gas stripping desulfurization using stripping gas. The hydrogen sulfide-containing gas after negative pressure gas stripping desulfurization is subjected to tail gas treatment;

[0038] S2. The water discharged after negative pressure desulfurization enters a pre-filter unit, and most of the petroleum and solid suspended matters in the gas field water are removed by the pre-filter. The generated slag is centrally transported for treatment;

[0039] S3. After the water discharged from the pre-filter is adjusted to a certain pH by a pH regulator, it enters an electro-oxidation unit. By controlling the voltage, most of the organic matters, ammonia nitrogen and other impurities in the water are oxidized and removed by electro-oxidation, and at the same time, the bromide ions in the gas field water are oxidized into free bromine; further, according to the gas-liquid phase equilibrium relationship of bromine, air is used to blow out the free bromine from the gas field water;

[0040] S4. After the water discharged from the electro-oxidation is adjusted to a certain pH by a pH regulator, it enters a post-filter to remove the solid impurities generated during the electro-oxidation process. The generated slag is centrally transported for treatment;

[0041] S5. The water discharged after filtration enters an adsorption lithium extraction unit, and the lithium adsorbent in the adsorption lithium extraction unit selectively adsorbs lithium ions in the filtered water. The water discharged after adsorption lithium extraction is the water for reinjection;

[0042] S6. The bromine-containing air after air blowing enters the chlorine washing unit, where the bromide ions in the chlorine washing liquid are used to displace and remove the chlorine gas by-produced in the electro-oxidation process and entrained in the air, and the generated free bromine is further carried out by the air and enters the next unit;

[0043] S7. The bromine-containing air after chlorine washing enters the first-stage absorption unit, where the free bromine in the air is absorbed by the absorption and reduction liquid to obtain sodium bromide. After the absorption liquid approaches saturation, sodium bromide products are prepared through evaporation and drying;

[0044] S8. The bromine-containing air after the first-stage absorption enters the second-stage absorption unit, where the remaining free bromine in the air is absorbed by the absorption and reduction liquid. When the first-stage absorption liquid is saturated, the second-stage absorption liquid is used as the first-stage absorption liquid and fresh absorption liquid is added externally as the second-stage absorption liquid for continuous cyclic operation;

[0045] S9. The lithium ions on the lithium adsorbent are desorbed using the desorbing liquid to obtain a qualified lithium-containing liquid;

[0046] S10. The qualified lithium-containing liquid enters the membrane separation concentration and evaporation concentration system for divalent ion separation and lithium ion concentration;

[0047] S11. The effluent after evaporation and concentration enters the resin impurity removal and lithium precipitation system to further remove the divalent ions therein and prepare lithium salt products (generally lithium carbonate) through precipitation reaction.

[0048] After the treatment of S1 - S5, the indexes of the effluent for reinjection obtained in S5 are as follows: sulfide ≤ 5 mg / L, petroleum substances ≤ 3 mg / L, suspended solids ≤ 5 mg / L, COD ≤ 50 mg / L, ammonia nitrogen ≤ 100 mg / L.

[0049] In the treatment of S1 - S5, the overall bromine recovery rate ≥ 90%, and the overall lithium recovery rate ≥ 70%, realizing the effective co-production of lithium and bromine resources.

[0050] Method for short - process co - production of lithium and bromine using sulfur - containing gas - field water: In the first step, taking advantage of the fact that sulfides in gas - field water exist in the form of hydrogen sulfide under acidic conditions and the solubility of hydrogen sulfide in water decreases under negative - pressure conditions, after adjusting the pH of the gas - field water, most of the hydrogen sulfide in the gas - field water is removed by negative - pressure steam stripping desulfurization. In the second step, a pre - filtration method is used to remove most of the suspended solids and petroleum substances in the gas - field water. In the third step, electro - oxidation is used to remove impurities such as organic matter and ammonia nitrogen in the gas - field water, and simultaneously, through the electro - oxidation effect, bromide ions in the water are oxidized to free bromine under acidic conditions. According to the gas - liquid equilibrium relationship between the gas - phase and liquid - phase concentrations of bromine, the free bromine is blown out of the gas - field water by air. In the fourth step, a post - filtration method is used to remove impurities in the electro - oxidized water. In the fifth step, a lithium adsorbent is used to selectively extract lithium ions from the filtered water, and the water after lithium adsorption extraction is reinjected or further deeply treated. Through the above five steps, the short - process extraction of lithium and bromine resources in gas - field water is realized, and combined with subsequent steps, the production of sodium bromide and lithium carbonate products is achieved.

[0051] In the sixth step, a chlorine - washing liquid is used to displace and remove chlorine gas generated in the electro - oxidation process and entrained in the air containing free bromine blown out by air. In the seventh step, an absorption reducing agent is used to perform a primary absorption on the free bromine entrained in the air after chlorine - washing, converting the free bromine into sodium bromide. When the primary absorption liquid is close to saturation, sodium bromide products are prepared through evaporation and drying. In the eighth step, an absorption reducing agent is used to perform a secondary absorption on the air after the primary absorption to further improve the conversion rate of free bromine. When the primary absorption liquid is saturated, the secondary absorption liquid is used as the primary absorption liquid and fresh absorption liquid is added as the secondary absorption liquid for continuous cyclic operation. In the ninth step, a desorbing liquid is used to desorb the lithium adsorbent to obtain a qualified lithium - containing solution. In the tenth step, the qualified lithium - containing solution enters a membrane separation concentration and evaporation concentration system for divalent ion separation and lithium - ion concentration. In the eleventh step, the concentrated solution enters a resin impurity - removal and lithium - precipitation system to further remove divalent ions therein and prepare lithium carbonate through a precipitation reaction.

[0052] The technical solution provided by the present invention has the following beneficial effects:

[0053] The present invention replaces the traditional "desulfurization - air flotation - advanced oxidation - flocculation sedimentation - filtration" pretreatment process of gas - field water with a short - process method of "desulfurization - electro - oxidation - filtration", cleverly using electro - oxidation to remove impurities such as organic matter and ammonia nitrogen in gas - field water, reducing their impact on the subsequent lithium adsorption extraction performance, and simultaneously realizing the oxidation extraction of bromide ions in gas - field water. Thus, the short - process co - production of lithium and bromine resources in gas - field water is achieved, and the pollutants in gas - field water are significantly reduced, which helps the sustainable and effective development of gas fields and alleviates the shortage of lithium and bromine supplies.

[0054] Through the realization of the short process, the present invention shortens the original gas field water treatment process, correspondingly reduces the addition of various chemicals in the process flow, reduces the loss of lithium and bromine resources caused by the addition of external chemicals and the long process flow, helps to improve the economy of extracting lithium and bromine resources from gas field water, and realizes the transformation of waste gas field water into valuable resources. Description of the Drawings

[0055] Figure 1 It is a schematic flow chart of the method for extracting lithium and bromine from gas field water by a short process;

[0056] Figure 2 It is a schematic flow chart of the method for extracting lithium and bromine from gas field water by a short process and preparing sodium bromide and lithium carbonate. Detailed Embodiments

[0057] For a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solutions of the present invention are described in detail below, but it should not be construed as a limitation on the implementable scope of the present invention.

[0058] Example 1

[0059] The present invention provides a method for co-producing lithium and bromine from sour gas field water by a short process, which is as follows:

[0060] The main characteristics of the produced water of a certain gas field are: the inlet pH is 6.21, sulfide is 420 mg / L, petroleum substances are 42.8 mg / L, suspended solids are 152.5 mg / L, COD is 2320 mg / L, ammonia nitrogen is 267 mg / L, lithium ions are 74.5 mg / L, and bromide ions are 618 mg / L;

[0061] As Figure 1 and Figure 2 shown, the treatment steps are as follows:

[0062] S1. The above sour gas field water is adjusted to pH 3.0 with hydrochloric acid, enters the negative pressure desulfurization unit, is air-stripped under the condition of an air-liquid ratio of 20:1, the operating pressure is -35 kPa, and the sulfur-containing air after air-stripping is treated by burning;

[0063] S2. The water after negative pressure desulfurization enters the pre-filter unit, and the filtration method is ceramic membrane filtration. The slag generated by filtration is centrally transported for treatment;

[0064] S3. The water after pre-filtration is adjusted to pH 3.0 with hydrochloric acid and then enters the electro-oxidation unit. Electro-oxidation and gas-liquid separation (air blowing) are carried out simultaneously in the electro-oxidation unit. The electro-oxidation voltage is 3.0 V, and the air blowing air-liquid ratio is 40:1, obtaining electro-oxidation effluent and bromine-containing air. The bromide ion in the electro-oxidation effluent is 15 mg / L;

[0065] S4. After the electro-oxidized effluent is adjusted to a pH of 11.0 with sodium hydroxide, it enters the post-filtration. The filtration method is sand filtration + glass filter media filtration, and the generated slag is collected and transported out for treatment;

[0066] S5. The effluent after post-filtration enters the lithium adsorption unit. The lithium adsorbent is a manganese-based adsorbent, and the effluent for reinjection is obtained after lithium adsorption; the lithium ion content in the effluent for reinjection is 13 mg / L;

[0067] S6. The bromine-containing air after air blowing enters the chlorine washing unit. The washing filtrate is sour gas field water, and the gas-liquid ratio for chlorine washing is 1:80;

[0068] S7. The bromine-containing air after chlorine washing enters the primary absorption unit. The absorption reduction solution is a mixture of sodium hydroxide and urea (molar ratio 1:6). When the density of the absorption solution reaches 1.38 g / cm 3 it is evaporated and dried to prepare sodium bromide products;

[0069] S8. The bromine-containing air after primary absorption enters the secondary absorption unit. The absorption reduction solution is the same as that in the primary absorption unit;

[0070] S9. Hydrochloric acid is used to desorb lithium ions from the lithium adsorbent to obtain a qualified lithium-containing solution. The lithium concentration in the qualified lithium-containing solution is 450 mg / L;

[0071] S10. The qualified lithium-containing solution enters the membrane separation concentration and evaporation concentration system. The total concentration of divalent metal ions in the effluent is 940 mg / L, and the lithium ion concentration is 16 g / L;

[0072] S11. The effluent after evaporation concentration enters the resin impurity removal and lithium precipitation system to obtain precipitated lithium salt products (lithium carbonate). The total concentration of divalent metal ions in the effluent is 30 mg / L.

[0073] After being treated by S1 - S5, the characteristics of the effluent for reinjection obtained in S5 are as follows: sulfide 4 mg / L, petroleum substances 2.8 mg / L, suspended solids 4.8 mg / L, COD 19 mg / L, ammonia nitrogen 28 mg / L, bromide ion content 15 mg / L, lithium ion content 13 mg / L.

[0074] After being treated by S1 - S5, the overall bromine recovery rate is ≥90%, and the overall lithium recovery rate is ≥70%, realizing the effective co-production of lithium and bromine resources.

[0075] Example 2

[0076] The present invention provides a method for short-process co-production of lithium and bromine using sour gas field water, specifically as follows:

[0077] The main characteristics of the produced water in a certain gas field are as follows: the pH of the influent water is 5.83, the sulfide content is 630 mg / L, the petroleum substances content is 130 mg / L, the suspended solid content is 260 mg / L, the COD is 4000 mg / L, the ammonia nitrogen content is 430 mg / L, the lithium ion content is 126.7 mg / L, and the bromide ion content is 550 mg / L;

[0078] The treatment steps are as follows:

[0079] S1. The above-mentioned sulfur-containing gas field water is adjusted to pH 2.0 with hydrochloric acid and then enters the negative pressure desulfurization unit. It is stripped with air under the condition of an air-liquid ratio of 60:1, and the operating pressure is -45 kPa. The sulfur-containing air after stripping is treated by the method of alkaline solution absorption;

[0080] S2. The water discharged after negative pressure desulfurization enters the pre-filtering unit. The filtering method is ceramic membrane + glass filter media filtration, and the slag generated by filtration is centrally transported for treatment;

[0081] S3. The water discharged from the pre-filtering is adjusted to pH 3.0 with hydrochloric acid and then enters the electro-oxidation unit. Electro-oxidation and gas-liquid separation (air blowing) are carried out simultaneously in the electro-oxidation unit. The electro-oxidation voltage is 3.5 V, and the air-blowing air-liquid ratio is 60:1, obtaining electro-oxidation effluent and bromine-containing air. The bromide ion content in the electro-oxidation effluent is 8 mg / L;

[0082] S4. The electro-oxidation effluent is adjusted to pH 7.0 with sodium hydroxide and then enters the post-filtering. The filtering method is sand filtration, and the slag generated is centrally transported for treatment;

[0083] S5. The water discharged after post-filtering enters the lithium adsorption and extraction unit. The lithium adsorbent is an aluminum-based adsorbent, and the water for reinjection is obtained after lithium adsorption and extraction; the lithium ion content in the water for reinjection is 24 mg / L;

[0084] S6. The bromine-containing air after air blowing enters the chlorine washing unit. The washing filtrate is the sulfur-containing gas field water, and the chlorine washing air-liquid ratio is 1:100;

[0085] S7. The bromine-containing air after chlorine washing enters the first-stage absorption unit. The absorption and reduction solution is a mixture of sodium hydroxide and urea (molar ratio 1:6). When the density of the absorption solution reaches 1.40 g / cm 3 sodium bromide products are prepared through evaporation and drying;

[0086] S8. The bromine-containing air after the first-stage absorption enters the second-stage absorption unit. The absorption and reduction solution is the same as that in the first-stage absorption unit;

[0087] S9. Neutral soft water is used to desorb the lithium ions on the lithium adsorbent to obtain a qualified lithium-containing solution. The lithium concentration in the qualified lithium-containing solution is 520 mg / L;

[0088] S10. The lithium-containing qualified liquid enters the membrane separation concentration and evaporation concentration system, and the total concentration of divalent metal ions in the effluent is 830 mg / L, and the lithium ion concentration is 20 g / L.

[0089] S11. The effluent after evaporation concentration enters the resin impurity removal and lithium precipitation system to obtain a precipitated lithium salt product (lithium carbonate), and the total concentration of divalent metal ions in the effluent is 28 mg / L.

[0090] After the treatment of S1 - S5, the characteristics of the effluent for reinjection obtained in S5 are as follows: sulfide 3 mg / L, petroleum substances 2.2 mg / L, suspended solids 3.6 mg / L, COD 46 mg / L, ammonia nitrogen 86 mg / L, bromide ion content 8 mg / L, lithium ion content 24 mg / L.

[0091] After the treatment of S1 - S5, the overall bromine recovery rate ≥ 90%, and the overall lithium recovery rate ≥ 70%, realizing the effective co-production of lithium and bromine resources.

[0092] Example 3

[0093] The present invention provides a method for co-producing lithium and bromine with a short process using sulfur-containing gas field water, specifically as follows:

[0094] The main characteristics of the produced water from a certain gas field are: inlet water pH 7.11, sulfide 120 mg / L, petroleum substances 23 mg / L, suspended solids 52 mg / L, COD 178 mg / L, ammonia nitrogen 256 mg / L, lithium ion 107.1 mg / L, bromide ion 176 mg / L.

[0095] The treatment steps are as follows:

[0096] S1. The above-mentioned sulfur-containing gas field water is adjusted to pH 5.0 with hydrochloric acid and enters the negative pressure desulfurization unit, and is air-stripped under the condition of an air-liquid ratio of 30:1, and the operating pressure is -30 kPa. The sulfur-containing air after air-stripping is treated by an alkali solution absorption method.

[0097] S2. The effluent after negative pressure desulfurization enters the pre-filter unit, and the filtration method is glass filter media filtration. The slag generated by filtration is transported out for centralized treatment.

[0098] S3. The effluent after pre-filtration is adjusted to pH 4.0 with hydrochloric acid and then enters the electro-oxidation unit. Electro-oxidation and air-liquid separation (air blowing) are carried out simultaneously in the electro-oxidation unit. The electro-oxidation voltage is 1.5 V, and the air blowing air-liquid ratio is 80:1 to obtain electro-oxidation effluent and bromine-containing air. The bromide ion in the electro-oxidation effluent is 14 mg / L.

[0099] S4. The electro-oxidation effluent is adjusted to pH 13.0 with sodium hydroxide and then enters the post-filter, and the filtration method is sand filtration + glass filter media filtration. The slag generated is transported out for centralized treatment.

[0100] S5. The effluent after post-filtration enters the lithium adsorption unit. The lithium adsorbent is a titanium-based adsorbent. After lithium adsorption, the effluent for reinjection is obtained. The lithium ion content in the effluent for reinjection is 19 mg / L.

[0101] S6. The bromine-containing air after air stripping enters the chlorine washing unit. The washing filtrate is sour gas field water, and the chlorine washing gas-liquid ratio is 1:60.

[0102] S7. The bromine-containing air after chlorine washing enters the primary absorption unit. The absorption reduction liquid is a mixture of sodium hydroxide and urea (molar ratio 1:6). When the density of the absorption liquid reaches 1.35 g / cm 3 it is evaporated and dried to prepare sodium bromide products.

[0103] S8. The bromine-containing air after primary absorption enters the secondary absorption unit. The absorption reduction liquid is the same as that in the primary absorption unit.

[0104] S9. Neutral soft water is used to desorb lithium ions on the lithium adsorbent to obtain a qualified lithium-containing solution. The lithium concentration in the qualified lithium-containing solution is 460 mg / L.

[0105] S10. The qualified lithium-containing solution enters the membrane separation concentration and evaporation concentration system. The total concentration of divalent metal ions in the effluent is 760 mg / L, and the lithium ion concentration is 18 g / L.

[0106] S11. The effluent after evaporation and concentration enters the resin impurity removal and lithium precipitation system to obtain precipitated lithium salt products (lithium carbonate). The total concentration of divalent metal ions in the effluent is 13 mg / L.

[0107] After being treated by S1-S5, the effluent for reinjection obtained in S5 has the following characteristics: sulfide 1 mg / L, petroleum substances 1 mg / L, suspended solids 1 mg / L, COD 14 mg / L, ammonia nitrogen 23 mg / L, bromide ion content 14 mg / L, lithium ion content 19 mg / L.

[0108] After being treated by S1-S5, the overall bromine recovery rate is ≥90%, and the overall lithium recovery rate is ≥70%, realizing the effective co-production of lithium and bromine resources.

Claims

1. A method for co-producing lithium bromine by using sulfur-containing gas field water in a short process, comprising the following steps: S1. Adjust the pH value of the influent water of the sulfur-containing gas field to acidic, and then perform negative pressure gas stripping treatment on it to obtain negative pressure desulfurization effluent and hydrogen sulfide tail gas; S2, pre-filtering the negative pressure desulfurization effluent to obtain pre-filtered effluent; S3, adjusting the pH value of the pre-filtered water to acidic, and then simultaneously performing electro-oxidation treatment and gas-liquid separation treatment on it to obtain electro-oxidation water and bromine-containing gas; S4, adjusting the pH value of the electro-oxidation effluent to neutral or alkaline, and then performing post-filtration to obtain post-filtered effluent; S5, using a lithium adsorbent to adsorb lithium ions in the post-filtered water to obtain effluent water for reinjection; and then desorbing the lithium adsorbent to obtain a lithium-containing liquid.

2. The method for co-producing lithium bromide with a short process using sulfur-containing gas field water according to claim 1, wherein, In S3, the voltage of electro-oxidation is 1.0-3.5V, and the bromide ion content of the electro-oxidation effluent is controlled to be ≤20mg / L.

3. The method for co-producing lithium bromide with a short process using sulfur-containing gas field water according to claim 2, wherein, In S3, the pH value of the pre-filtered water is adjusted to 2-6.

4. The method for co-producing lithium bromide with a short process using sulfur-containing gas field water according to claim 2, wherein, In S3, the gas-liquid separation treatment method is: introducing gas into the liquid undergoing electro-oxidation to blow out the bromine element generated by the electro-oxidation in the liquid; Preferably, the gas-liquid ratio during gas-liquid separation is 20-200:1; Preferably, the gas is air.

5. The method for co-producing lithium bromide with a short process using sulfur-containing gas field water according to claim 1, wherein, In S1, the pH value of the influent water from the sour gas field is adjusted to 2-6; Preferably, in the negative pressure gas stripping treatment, the gas is at least one of air, nitrogen and fuel gas, the operating pressure is ≤-30 kPa, and the gas-liquid ratio is ≥10:

1.

6. The method for co-producing lithium bromide with a short process using sulfur-containing gas field water according to claim 1, wherein, In S2 and S4, the pre-filtration and / or post-filtration method includes one or a combination of two or more of sand filtration, ceramic membrane filtration, and glass filter material filtration.

7. The method for co-producing lithium bromide through a short process using sulfur-containing gas field water according to claim 1, wherein, In S4, the pH value of the electro-oxidation effluent is adjusted to 7-13; Preferably, the pH adjuster includes at least one of hydrochloric acid, nitric acid, sodium hydroxide and potassium hydroxide.

8. The method for co-producing lithium bromide with a short process using sulfur-containing gas field water according to claim 1, wherein, In S5, the lithium ion content in the gas field water after adsorption is ≤15 mg / L; Preferably, the lithium adsorbent includes one or a combination of two or more of an aluminum adsorbent, a manganese adsorbent, and a titanium adsorbent.

9. The method for co-producing lithium bromide with a short process using sulfur-containing gas field water according to claim 1, wherein, In S5, the lithium ion concentration in the lithium-containing liquid is ≥100 mg / L; Preferably, the desorbent used to desorb the lithium adsorbent includes at least one of neutral soft water, hydrochloric acid and sulfuric acid.

10. The method for co-producing lithium bromide with a short process using sulfur-containing gas field water according to claim 1, wherein, The indicators of the sulfur-containing gas field water inflow include: pH 5-8, sulfide 10-1000mg / L, petroleum 5-200mg / L, suspended solids 5-500mg / L, COD 10-5000mg / L, ammonia nitrogen 10-500mg / L, lithium ion 50-500mg / L, bromide ion 50-3000mg / L.

11. The method for co-producing lithium bromide through a short process using sulfur-containing gas field water according to claim 1, wherein, The method further comprises the steps of: The bromine-containing gas obtained by S2 is washed with chlorine by using a chlorine washing liquid, and then the free bromine in the bromine-containing gas is absorbed by a reducing absorption liquid to obtain a bromine product; Preferably, the reducing absorption liquid is a mixture of sodium hydroxide and urea in a mass ratio of 1:5-7, and the obtained bromine product is sodium bromide.

12. The method for co-producing lithium bromide through a short process using sulfur-containing gas field water according to claim 11, wherein, The absorption process of bromine in bromine-containing gas includes primary absorption and secondary absorption; Preferably, during the chlorine washing process, the chlorine washing liquid is one of the sulfur-containing gas field water inlet water, the primary absorption liquid or the secondary absorption liquid, and the gas-liquid ratio of the bromine-containing gas to the chlorine washing liquid is ≤1:

80.

13. The method for co-producing lithium bromide with a short process using sulfur-containing gas field water according to claim 1, wherein, The method further comprises the following steps: Performing membrane separation concentration and evaporation concentration on the lithium-containing liquid to obtain a lithium concentrate; then performing resin impurity removal and lithium precipitation on the lithium concentrate to obtain a lithium salt product.

14. The method for co-producing lithium bromide with a short process using sulfur-containing gas field water according to claim 13, wherein, The lithium ion concentration in the lithium concentrate is ≥15 g / L, and the total concentration of divalent metal ions is ≤1000 mg / L. The divalent metal ions include at least one of calcium ions, magnesium ions, barium ions, and strontium ions; Preferably, the total concentration of divalent metal ions in the lithium concentrate after resin impurity removal is ≤50 mg / L.

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