CN102070260B - Wastewater recycling method and device for collection pipe section of dry distillation system for oil shale - Google Patents

Abstract

The invention relates to a wastewater recycling method and device for a collection pipe section of a dry distillation system for oil shale. The wastewater recycling method for a collection pipe section of a dry distillation system for oil shale, which is provided by the invention, comprises the following steps: firstly, settling dry distillation wastewater at the outlet of the collection pipe, and then, removing dust by cyclone to remove oil sludge to obtain circulating water subjected to primary purification; removing oil by cyclone in the obtained circulating water subjected to primary purification to remove oil stain to obtain circulating water subjected to secondary purification; and returning the obtained circulating water subjected to secondary purification to the collection pipe to be recycled as washing water and cooling water. The invention also provides a wastewater recycling device for the collection pipe section of the dry distillation system for oil shale.

Description

Method and device for recycling waste water in collection pipe section of oil shale retort system

technical field

The invention belongs to the fields of petrochemical industry and environmental protection, and relates to a process method for recycling waste water in a collection pipe section of an oil shale dry distillation system, which is suitable for treating waste water at the outlet of a collection pipe in the oil shale dry distillation process. Specifically, the present invention provides a method and device for deoiling, deslagging, and recycling the circulating water in the collecting pipe section in the oil shale carbonization system.

Background technique

Oil shale is an associated resource of coal. Using oil shale dry distillation technology to refine crude oil and its by-products once supported my country's economic construction in the oil-poor period, but its research and development once shrank year by year. In the early 1990s, Fushun Mining Group introduced the concept of circular economy and restarted the comprehensive utilization and research and development of oil shale, among which oil shale refining was the most important.

When oil shale is retorted to produce shale oil, it will also produce a large amount of retort sewage. The retort sewage in the collection pipe section is mainly composed of the following parts:

(1) Associated water in the mixed gas derived from the top of the retort furnace: it is composed of raw oil shale belt water, main wind belt water, basin evaporated water and a small amount of chemically combined water. During the process, it exists in the form of water vapor, and gradually condenses into water after entering the mixed gas manifold, which is the main source of dry distillation sewage;

(2) Processing, flushing and drainage of the retort product in the collecting pipe section: washing and processing the retort product in the collecting pipe section, and recovering the water generated in the process of shale oil.

Dry distillation sewage is a kind of sewage with various pollutants, complex components and high concentration. In addition to common petroleum substances and volatile phenolic compounds in general natural oil plants, it also contains a large amount of organic sulfur, organic nitrogen and naphthenic acid Environmental pollutants such as compounds and polycyclic aromatic hydrocarbons are currently recognized as difficult-to-treat organic sewage in the world, and are also one of the industrial sewage that the country has introduced key treatment technologies. At home and abroad, the laboratory treatment of shale retort sewage has been carried out successively, but due to the high investment in equipment and the corresponding economic benefits are not ideal, they are stranded, and the sewage treatment is difficult.

In the current common oil shale carbonization production process, the coke oven gas and tar at the outlet of the carbonization furnace enter the manifold under normal pressure and are washed by circulating water to remove the sludge (a mixture of heavy oil and dust) in the gas, washing The process is also the process of cooling and separating coke oven gas and coal tar.

Generally, the treatment method for dry distillation sewage in the collecting pipe section is to simply settle the oily and muddy sewage in the mud collecting tank and then directly return to the collecting pipe. That is, the collecting pipe has a certain slope, so that the washing water, sludge and shale oil after leaching can flow into the mud collecting tank along the collecting pipe for sedimentation and separation. The water in the mud collection tank is pumped out by the mud collection tank water pump and enters the manifold for recycling, and the mud collection tank regularly discharges the sludge and sends it to the building materials for comprehensive utilization.

Although this has achieved zero discharge of sewage and saved a lot of sewage treatment costs, there are problems of serious equipment corrosion, pipeline blockage and corrosion.

So far, the field has not yet developed a method that can effectively treat the wastewater in the header section of the oil shale retort system.

Therefore, there is an urgent need in this field to develop a method that can effectively treat the wastewater in the header section of the oil shale retort system, and this method can solve the problems of severe equipment corrosion, pipeline blockage and corrosion in the prior art.

Contents of the invention

The invention provides a new method and device for recycling waste water in the collection pipe section of the oil shale retort system, which can return part of the sewage to the collection pipe directly after proper treatment, and use it as cooling and washing water recycling, which not only solves the problem of sewage treatment , also saves a large amount of fresh water, realizes the recycling of water resources, greatly reduces the loss of energy, thereby overcomes the defects existing in the prior art.

In one aspect, the present invention provides a method for recycling waste water in the manifold section of an oil shale retort system, the method comprising:

Precipitate the dry distillation wastewater at the outlet of the collecting pipe first, and then perform cyclone dust removal to remove the sludge and obtain a purified circulating water;

Cycling and degreasing the obtained primary purified circulating water to remove oil stains to obtain secondary purified circulating water;

The resulting secondary purified circulating water is returned to the manifold for reuse as washing water and cooling water.

In a preferred embodiment, the obtained secondary purified circulating water has a mud content of 0 and an oil content of less than 0.001% by volume, based on the volume of the obtained secondary purified circulating water.

In another aspect, the present invention provides a waste water recycling device in the collection pipe section of an oil shale retort system, the device comprising:

A mud collecting tank connected to the water outlet of the collecting pipe is used to settle the dry distillation wastewater at the outlet of the collecting pipe, and a collecting pipe dust collector connected to the water outlet of the mud collecting tank is used to cyclone the precipitated dry distillation wastewater Dust removal to remove sludge and obtain purified circulating water;

A manifold degreaser connected to the water outlet of the manifold dust collector is used to swirl degreasing the obtained primary purified circulating water to remove oil stains and obtain secondary purified circulating water;

Wherein, the obtained secondary purified circulating water is returned to the manifold, and reused as washing water and cooling water.

In a preferred embodiment, the manifold dust collector is arranged in series with the mud collection tank, and the dust collector is selected from cyclone dust collectors.

In another preferred embodiment, the manifold degreaser is arranged in series with the manifold dust collector, and the deoiler is selected from cyclone degreasers.

In another preferred embodiment, the manifold dust collector is used in a single-stage or multi-stage series combination.

In another preferred embodiment, the manifold oil remover is used in a single-stage or multi-stage combination in series.

In another preferred embodiment, the device further includes a pump arranged between the mud collecting tank and the collecting pipe dust collector, and is used to pump the circulating water from the water outlet of the mud collecting tank to the collecting pipe dust collector.

Description of drawings

Fig. 1 is a schematic flow diagram of recycling waste water in a header section of an oil shale retort system according to an embodiment of the present invention.

Detailed ways

After extensive and in-depth research, the inventors of the present invention have found that the retort tar gas in the oil shale retort system is washed and cooled by circulating water in the manifold to rinse the tar and tar gas in the manifold. For a large amount of oily and muddy wastewater, if an oil and mud removal device is installed at the outlet of the manifold of the oil shale retort system, the oil sludge and oil stains contained in it can be effectively removed, so that the circulating water can be purified and separated by cyclone The purified circulating water is returned to each device as washing and cooling water, which avoids impurities in the water from clogging or corroding pipes and equipment, and reduces the difficulty and amount of sewage treatment. The present invention has been accomplished based on the above findings.

Technical conception of the present invention is as follows:

1. The oil-mud-water mixture produced during the cooling and washing process of the header part of the oil shale retort process contains a large amount of sludge formed by shale dust and retort oil. One-step desilting can well achieve the purpose of removing sludge from circulating water;

2. Install a manifold degreasing device at the outlet of the manifold dust collector to remove oil from the desilted oily sewage, which can well achieve the purpose of degreasing the circulating water;

3. Return the purified circulating water after degreasing and desilting to the manifold for reuse as washing water and cooling water, and continue to cool down and wash the coke oven gas and tar in it.

In a first aspect of the present invention, there is provided a method for recycling waste water from an oil shale carbonization system, the method comprising:

The dry distillation wastewater at the outlet of the collecting pipe enters the mud collecting tank, and part of the sludge with large volume and density is precipitated; then the dry distillation wastewater at the outlet of the mud collecting tank enters the collecting pipe dust collector, and the remaining sludge is further removed to obtain circulating water after preliminary desilting and purification ;

The circulating water at the outlet of the collecting pipe dust collector enters the collecting pipe degreaser to remove the oil and obtain purified circulating water;

The circulating water at the outlet of the manifold degreaser returns to the manifold for reuse as washing water and cooling water.

In the present invention, after washing and cooling the tar gas and tar in the washing and cooling water of the collecting pipe section, the oil sludge and oil stains therein are removed step by step, and returned to the collecting pipe for use as washing water and cooling water to form a relatively complete and Independent washing and cooling water recycling process.

In the present invention, a step-by-step oil sludge removal method is adopted. First, a mud collecting tank is installed at the outlet of the manifold to settle part of the sludge, and then the residual sludge is removed by setting the manifold dust collector.

In the present invention, the circulating water after desilting treatment enters the collecting pipe degreaser to remove oil stains in the circulating water.

In the present invention, the purified circulating water is returned to the top of the collecting pipe to rinse and cool the retorted oil and gas therein. The mud content of the circulating water is 0 and the oil content is lower than 1%.

In a second aspect of the present invention, there is provided a device for recycling waste water in the header section of an oil shale retort system, the device comprising:

The mud collecting tank used for the recycling of dry distillation wastewater for preliminary desilting is set at the outlet of the collecting pipe;

A collecting pipe dust collector connected to the water outlet of the mud collecting tank is used for desilting the dry distillation wastewater;

A manifold oil remover connected to the outlet of the manifold dust collector is used for dry distillation wastewater degreasing.

In the present invention, the collecting pipe dust collector is located at the water outlet of the mud collecting tank, and the dust collector can be a cyclone dust collector or other various solid-liquid separation equipment.

In the present invention, the water outlet of the collecting pipe dust collector is arranged in series with the subsequent collecting pipe degreaser, and the degreaser can be a swirl flow degreaser or other various types of oil-water separation equipment.

In the present invention, the manifold degreaser or manifold dust collector is used in a single-stage or multi-stage series combination.

The method and device of the present invention can also be used in the step-by-step separation process of other oil-water mixtures.

Refer to the accompanying drawings below.

Fig. 1 is a schematic flow diagram of recycling waste water in a header section of an oil shale retort system according to an embodiment of the present invention. As shown in Figure 1, the oil gas at the outlet of the carbonization furnace enters the manifold 1 under normal pressure, and is rinsed and cooled by circulating water; after the circulating water contacts the tar gas and gas carrier in the tower, the tar gas in it is cooled and condensed into dry distillation crude oil At the same time, the oil sludge formed by the shale dust is washed away, and the oil-water-mud three-phase mixture produced in this process is discharged from the water outlet as dry distillation wastewater (part of the oil and gas goes out of the manifold 1 and enters the subsequent part for treatment); the dry distillation wastewater enters the mud collection Tank 2, in which the oil sludge with large density and volume settles down, the oil-water mixture carries the remaining oil sludge and discharges, and the first step of oil sludge separation is completed; the dry distillation wastewater is pumped into the manifold dust collector 4 with the pump 3, and the strong vortex flow field generated by high pressure and centrifugal force to remove the oil sludge and enter the oil sludge treatment part for further treatment; dry distillation wastewater enters the manifold oil remover 5 from the overflow port of the manifold dust collector 4, and removes the sludge through the strong vortex flow field and centrifugal force generated by high pressure. Oil stains enter the subsequent oil separation treatment from the overflow port of the degreaser 5 in the manifold; the retort wastewater after the above oil and mud removal treatment basically meets the conditions for being used as circulating water, and circulates back to the manifold for use as washing water and cooling water.

The main advantages of the method and device of the present invention are:

The present invention adopts the liquid-liquid separation technology and the solid-liquid separation technology to purify and recycle the oily and muddy waste water of the oil shale dry distillation system, avoiding impurities in the water from clogging or corroding pipelines and equipment, and reducing the difficulty and cost of sewage treatment. throughput. The method of the invention has advanced technology, low equipment investment cost, small occupied area, low failure rate, and can effectively reduce the oil-mud content in circulating water and related energy consumption.

Example

The present invention is further described below in conjunction with specific examples. However, it should be understood that these examples are only used to illustrate the present invention and not to limit the scope of the present invention. The test methods for which specific conditions are not indicated in the following examples are generally in accordance with conventional conditions, or in accordance with the conditions suggested by the manufacturer. All percentages and parts are by weight unless otherwise indicated.

Example 1: Energy-saving and emission-reduction technical transformation project of oil shale retort plant

Process flow:

This project adopts the device of the present invention, and its technological process is as shown in Figure 1.

The cooling and washing water in the collecting pipe section has a high mud content, and dust removal treatment is required to prevent the oil sludge from clogging and corroding the process pipeline. Tube degreaser for wastewater degreasing and purification.

The oil gas at the outlet of the carbonization furnace enters the manifold 1 under normal pressure, and is rinsed and cooled by circulating water; after the circulating water contacts with the tar gas and gas carrier in the tower, the tar gas in it is cooled and condensed into dry distillation crude oil, and the tar gas in it is washed away at the same time Oil sludge formed by shale dust, the oil-water-mud three-phase mixture produced in this process is discharged from the water outlet as dry distillation wastewater;

Dry distillation waste water enters the sludge collection tank 2, in which the sludge with large density and volume settles down, and the oil-water mixture carries the remaining sludge and is discharged, and the first step of the initial separation of sludge is completed;

The dry distillation waste water is pumped into the manifold dust collector 4 with the pump 3, and the dust collector is a cyclone dust collector, and the oil sludge therein is removed through the strong vortex flow field and centrifugal force generated by high pressure;

The dry distillation wastewater enters the manifold degreaser 5, which uses a swirl degreaser to remove the oil stains therein through the strong vortex flow field and centrifugal force generated by high pressure;

The retorted waste water after the above deoiling and deslagging treatment basically meets the conditions for being used as circulating water, and is pumped into the manifold through the circulating pump to be used as washing water and cooling water.

Such a reciprocating cycle forms a recycling system for washing and cooling water.

Technical effect:

In this process, the flow rate at the inlet of the manifold section cyclone is 212650kg/h, the flow rate at the top outlet is 207650kg/h, and the flow at the bottom outlet is 5000kg/h, and the mud content (referring to oil rock ash) is 416mg/L, and the oil content It is 11952mg/L. After the washing and separation of the collecting pipe section, the mud content (referring to oil rock ash) in the outlet mixed gas is 95mg/L, the oil content is 3187mg/L, and the amount of sludge is reduced by about 75%; after washing and separation of the collecting pipe section , the mud content (referring to oil rock ash) at the inlet of the separator of the air tower and subsequent towers is 0, and the oil content is 500mg/L; Drop 0.10MPa. When the sludge content in the influent is not greater than 2000mg/L, the muddy water concentration at the water phase outlet of the cyclone dust collector is not greater than 300mg/L; The flow rate of the sludge phase is not greater than 10% of the inlet flow rate of the cyclone dust collector. The pressure drop between the inlet of the cyclone degreaser and the outlet of the water phase is 0.15-0.25MPa. When the oil content of the cyclone degreaser is not more than 2000mg/L, the oil concentration at the outlet of the water phase is not more than 200mg/L; when the oil content of the inlet water is not more than 1000mg/L, the oil concentration at the outlet of the water phase is not more than 150mg/L; The qualified rate of the analytical value of the specified frequency (not greater than 200mg/L or not greater than 150mg/L) is ≥95%. The oil phase flow of the cyclone degreaser is about 5% of the inlet flow of the cyclone degreaser, and the control is not more than 10%. The circulating water has a good degreasing and desilting effect.

All documents mentioned in this application are incorporated by reference in this application as if each were individually incorporated by reference. In addition, it should be understood that after reading the above teaching content of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

Claims (4)

1. an oil shale distillation system is gathered the pipeline section wastewater recycling method, and the method comprises:

The destructive distillation waste water of pair set pipe outlet precipitates first, then carries out rotational flow dust-removing, to remove greasy filth, obtains the recirculated water of primary purification;

Recirculated water to the primary purification of gained carries out cyclone deoiling, with except degreasing, obtains the recirculated water of secondary-cleaned;

The recirculated water of the secondary-cleaned of gained is returned collecting tubule, re-uses as washing water and water coolant,

Wherein, the silt content of the recirculated water of the secondary-cleaned of gained is 0, and oleaginousness is lower than 0.001 volume %, with the volumeter of the recirculated water of the secondary-cleaned of gained.

2. an oil shale distillation system that is used for method claimed in claim 1 is gathered the pipeline section waste water circulation utilized device, and this device comprises:

The collection mud tank (2) that is connected with the water outlet of collecting tubule (1), the destructive distillation waste water that is used for the outlet of pair set pipe precipitates, and the collecting tubule fly-ash separator (4) that is connected with the water outlet of collection mud tank (2), be used for the destructive distillation waste water through precipitation is carried out rotational flow dust-removing, to remove greasy filth, obtain the recirculated water of primary purification;

The collecting tubule oil eliminator (5) that is connected with the water outlet of described collecting tubule fly-ash separator (4) is used for the recirculated water of the primary purification of gained is carried out cyclone deoiling, with except degreasing, obtains the recirculated water of secondary-cleaned;

Wherein, the recirculated water of the secondary-cleaned of gained returns collecting tubule (1), re-uses as washing water and water coolant; Described fly-ash separator is selected from cyclone dust, and described oil eliminator is selected from degreaser cyclone;

Described collecting tubule fly-ash separator and collection mud tank arranged in series;

Described collecting tubule oil eliminator and collecting tubule duster parallels are arranged;

This device also comprises the pump (3) that is arranged between collection mud tank and the collecting tubule fly-ash separator, sends into the collecting tubule fly-ash separator for the water circulating pump that will collect mud tank water outlet.

3. device as claimed in claim 2 is characterized in that, described collecting tubule fly-ash separator uses in the mode of single-stage or plural serial stage combination.

4. device as claimed in claim 2 is characterized in that, described collecting tubule oil eliminator uses in the mode of single-stage or plural serial stage combination.

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