Oil gas recovery device and method

Oil and gas recovery equipment and methods

Technical field

[0001] The present invention relates to the field of exhaust gas treatment, and more particularly to an oil and gas recovery apparatus and method.

Background technique

(VOCs) (volatile organic compounds), VOCs not only seriously worsen the people's living environment, endanger human health, but also to the enterprise and the community with a large number of volatile oil, To a serious waste of resources, security risks and economic losses. VOCs mainly include hydrocarbons, alcohols, ethers, aldehydes, phenols, esters, fatty acids, amines and organic halogenated derivatives, some of which have a recycling value of organic waste gas. With the increasingly stringent emission standards for organic pollutants at home and abroad, the treatment and recycling of VOCs has received more and more attention. The pollution control of VOCs has always been the focus of environmental researchers, especially oil and gas recovery, And has developed a number of industrial applications.

The main technical methods for oil and gas recovery in current industrial processes include absorption, adsorption and condensation. However, the practical application results show that these methods are easy to be used in a single process. Problem, and the recovery effect can not reach the best condition. Absorption method in the application process, the equipment occupies a large space, the performance requirements of the absorbent is very strict, absorbent consumption, need to continue to add, and the recovery rate is low, not up to the current national standards. Adsorption method is usually used in the process of adsorption of activated carbon is relatively good as an adsorbent, and activated carbon recovery of oil and gas adsorption device is higher, the adsorption temperature increased rapidly, which will not only seriously affect the adsorption performance of activated carbon and service life, but also There may be fire and other security risks. In the application of the condensation method can be found, because the method is an indirect heat transfer, the need to reach a very low temperature conditions can make the recovery efficiency is ideal, investment and operating costs are relatively high.

[0004] There are many problems in the conventional condensing-adsorption-vacuum desorption process such as low efficiency of vacuum desorption at room temperature, remnant of organic matter on the adsorbent, low concentration of air, and low concentration of air in the petroleum, petrochemical and chemical industries. Large amount of desorption gas concentration of organic matter is low, condensation recovery efficiency is low, consume too much energy, resulting in increased production costs.

Summary of the Invention

[0005] In order to solve the above-mentioned technical problems, the present invention provides an efficient and energy-efficient oil and gas recovery apparatus and method for the deficiencies of existing oil and gas recovery technologies.

An oil / gas recovery device includes an anti-exposure centrifugal fan I, a cold box 2, a refrigeration unit 3, a liquid storage tank 4, a liquid returning chestnut 5, an oil storage tank 6, a first adsorption tank 7, a second adsorption tank 8, a vacuum chestnut 9, a nitrogen generating unit 10, and a PLC automatic control system, wherein the cold box 2 includes a pre-cooling section 21, a primary condensation section 22, a secondary condensation section 23, Stage condensing unit 23 is connected to the pre-cooling unit 21, and the primary condensing unit 22 and the secondary condensing unit 23 are connected to the refrigerating unit 3, respectively; the oil and gas is first fed into the cold box 2 by the anti-exposure centrifugal fan I, The two-stage condensing liquid 23 is sent to the liquid storage tank 4 and is fed back to the oil storage tank 6 through the liquid-returning chestnut 5. The oil condensed from the secondary condensing section 23 The pre-cooling section 21 is supplied with heat to the first adsorption tank 7, and the first adsorption tank 7 and the second adsorption tank 8 are cyclically switched for adsorption and desorption, and when the first adsorption tank 7 or the second adsorption tank 8, the vacuum chestnut 9 is opened, and when the vacuum degree of the adsorption tank 8 reaches the set value, the hot nitrogen gas is opened by the second three-way valve 12, the oil gas is desorbed by the hot nitrogen gas, and the desorbed oil and gas From the vacuum chestnut 9 through the storage tank 4 back to the anti-exposure centrifugal fan I inlet and the initial oil and gas mixture.

[0007] Further, other adsorption vessels are also included in parallel with the first adsorption tank 7, one of which is used for desorption and regeneration, and the other tanks are switched in parallel for adsorption, adsorption and desorption, the switching being done automatically by the control system , After the desorption regeneration regeneration automatically replace the adsorption tank adsorption time of the longest tank, and the adsorption time of the longest tank to switch to desorption regeneration, switch to the adsorption desorption tank and other adsorption tank in parallel with the adsorption.

Further, the refrigeration unit (3) includes a first compressor (31), a second compressor (32), a heat exchanger (33), an air-cooled condenser (34), a condensing evaporator (35), a first expansion valve (36), a second expansion valve (37) , And a third expansion valve (38), which in turn connects the heat exchanger (33), the air-cooled condenser (34), and the first expansion valve (36) to provide refrigeration for the primary condensation section (22), and the second compressor The condensing evaporator 35 and the third expansion valve 38 are connected to provide a cooling capacity for the secondary condensation section 23 while the second expansion valve 37 is connected to the condensing evaporator 35 at the outlet of the air-cooled condenser 34 so that the refrigerant is compressed by the first- Is supplied to the condensing evaporator (35) through the second expansion valve (37).

[0009] Further, the first three-way valve 11 controls the discharge of the tail gas after the adsorption.

[0010] Further, the first compressor 31 compresses the heat generated by the refrigerant to heat the nitrogen gas generated in the nitrogen generating unit 10. [

[0011] Further, the vacuum chestnut 9 is a dry screw vacuum chestnut with frequency conversion and anti-exposure.

In addition, the present invention provides a method for recovering oil and gas using the oil / gas recovery apparatus as described above.

[0013] Further, the temperature of the oil and gas inlet of the adsorption tank for adsorption is controlled to be 40 ° C or less, the normal operation temperature of the adsorption tank for adsorption is between 37 ° C and 48 ° C, the superficial velocity is 0.2 to 1.5 m / S.

[0014] Further, the temperature of the nitrogen gas entering the adsorption tank for desorption was controlled to be 50 to 60 ° C, and the desorption time was set to 15 to 20 min

Further, the adsorbent used in the adsorption device is activated carbon, activated carbon fiber or silica gel.

[0016] [0016]

As will be apparent from the foregoing description of the present invention, the present invention is advantageous in that,

1. The invention utilizes the advantages of the condensation method and the adsorption method to optimize the combination to achieve the purpose of reducing the energy consumption and eliminating the hidden trouble of safety.

[0017] 2. The invention adopts the condensed oil and gas as the pre-cooling medium of the adsorption tank to save the energy consumption, meanwhile the oil and gas in the first adsorption tank has a reasonable inlet temperature, and the desorbed oil and gas is firstly recovered through the liquid storage tank Part of the oil and gas is not returned to the anti-exposure centrifugal fan before the fan and the initial mixture of oil and gas to improve the concentration of oil and gas, while improving the recovery rate of oil and gas, the invention can achieve the recovery rate of not less than 98.5%.

[0018] 3, the use of vacuum chestnut desorption, vacuum to achieve high vacuum, the need to use multi-stage vacuum system, high cost. The invention utilizes a single-stage vacuum chestnut with a small amount of nitrogen gas heated by the refrigerating unit for vacuum thermal desorption to achieve good desorption effect, lower operating cost and energy consumption, and also facilitates unloading vacuum to prepare for the next cyclic adsorption . On the other hand, hot nitrogen temperature control in 50 ° 060 ° C, to avoid the carbonization of some organic matter, but also to avoid the spontaneous combustion of activated carbon.

BRIEF DESCRIPTION OF THE DRAWINGS Fig

1 is a block diagram of the structure of the present invention. 1, an anti-exposure centrifugal fan I, a cold box 2, a refrigeration unit 3, a liquid storage tank 4, a liquid returning chest 5, an oil storage tank 6, a first adsorption tank 7, a second adsorption tank 8, The first compressor 31, the second compressor 32, the heat exchanger 33, the air-cooled condenser 34, the condensing evaporator 35, the first condenser 31, the second compressor 22, the second condenser 23, the nitrogen generator 10, the pre-cooling section 21, The first three-way valve 11, the second three-way valve 12, the third three-way valve 13, the fourth three-way valve 14, the first expansion valve 36, the second expansion valve 37 and the third expansion valve 38.

detailed description

The present invention will be further described below with reference to the accompanying drawings and specific examples, but the present invention is not limited thereto.

An oil and gas recovery device includes an anti-exposure centrifugal fan I, a cold box 2, a refrigeration unit 3, a liquid storage tank 4, a liquid returning chestnut 5, an oil storage tank 6, a first adsorption tank 7 and a second adsorption tank 8 , A vacuum chestnut 9, a nitrogen generating unit 10 and a PLC automatic control system. The VOCs oil and gas are first conveyed into the cold box 2 by an anti-exposure centrifugal fan I, and the cold box 2 comprises a pre-cooling section 21, a primary condensing section 22, Stage condensing section 23 in which the secondary condensing section 23 is connected to the pre-cooling section 21 so that the cooling capacity of the pre-cooling section 21 comes from the oil vapor from the secondary condensing section 23. The primary condensing section 22 and the secondary condensing section 23 are connected To the refrigerating unit 3 so that the cooling capacities of the primary condensing section 22 and the secondary condensing section 23 come from the refrigerating section 3, and the refrigerating section 3 includes a first compressor 31, a second compressor 32, a heat exchanger 33, A cold condenser 34, a condensing evaporator 35, a first expansion valve 36, a second expansion valve 37, and a third expansion valve 38. The first compressor 31 is connected to the heat exchanger 33, the air-cooled condenser 34, An expansion valve 36 for supplying the cooling capacity to the primary condensation section 22, and a second compressor 32 for connecting the condensing evaporator 35 and the third expansion valve 38 to provide cooling capacity for the secondary condensation section 23 while the air- The second expansion valve 37 is also connected to the condensing evaporator 35 so that a portion of the refrigerant compressed by the first stage and condensed is supplied with the cooling capacity to the condensing evaporator 35 via the second expansion valve 37.

[0022] The liquid condensed in the pre-cooling section 21, the primary condensing section 22 and the secondary condensing section 23 of the cold box 2 is sent to the liquid storage tank 4 and sent to the oil storage tank 6 for recovery ; The oil condensed from the secondary condensing section 23 is supplied to the first adsorption tank 7 through the third three-way valve 13 and is controlled by the first three-way valve 11, and the heat is supplied to the first adsorption tank 7 is used for adsorption of volatile VOCs, such as activated carbon and activated carbon fibers, and when the concentration of the exhaust gas is monitored to be close to the emission value required by the environment, the adsorption of activated carbon in the first adsorption tank 7 Nearly all of the inlet and outlet valves of the second adsorption tank 8 are closed, the third three-way valve 13 and the first three-way valve 11 of the communicating suction tank 8 are opened, and the second adsorption tank 8 for desorption and regeneration is closed Into the first adsorption tank 7 to participate in the adsorption of oil and gas, adsorption adsorption of the first adsorption tank 7 began to carry out desorption and regeneration, the entire switching process by the PLC system control to ensure continuous operation of the system;

Other adsorption vessels may also be included in parallel with the first adsorption vessel 7, each of which has a separate outlet oil and gas concentration detection device, one for desorption and regeneration, and the other tanks for adsorption, adsorption and desorption in parallel The tank with the longest adsorption time can be replaced by the tank with the longest adsorption time. The tank with the longest adsorption time is switched to the desorption regeneration, and switched to the adsorption desorption tank and other adsorption tanks in parallel for adsorption. Since two or more adsorbent vessels are used for adsorption, they are switched by the desorption tank. Therefore, the adsorption time of the organic solvent varies with each adsorption tank. There is a time difference between the time of reaching the saturation time. Desorption cans, another desorption tank and then switch to the adsorption tank and other adsorption tank in parallel with the adsorption, adsorption and desorption of the mutual switch are automatically controlled by the PLC system to complete, to ensure the continuity of system operation.

When the first adsorption tank 7 or the second adsorption tank 8 is switched to the desorption stage, the vacuum chestnut 9 is opened and when the vacuum degree of the adsorption tank reaches the set value, the hot nitrogen gas is opened by controlling the second three- , With hot nitrogen adsorption of activated carbon on the oil and gas desorption. The hot nitrogen is from the nitrogen generator, and the normal temperature nitrogen is heated by the heat of the refrigerant coming out of the first-stage compressor of the refrigeration unit. The vacuum chestnut is the dry screw vacuum chestnut with frequency conversion and anti- ; Desorption of oil and gas from the vacuum chestnut 9 through the storage tank back to the anti-exposure centrifugal fan inlet and the initial oil and gas mixture.

[0024] The entire system is automatically controlled by the PLC for continuous operation. In order to ensure that the adsorption capacity of activated carbon adsorption tank for adsorption of VOCs oil and gas inlet temperature is less than or equal to 40 ° C, the adsorption tank for each adsorption of the normal working temperature between 37 ° C ~ 48 ° C, The temperature of the nitrogen gas entering the adsorption tank for desorption is 50 to 60 ° C (the high temperature is favorable for the desorption of the activated carbon, but the desorption of the activated carbon Too high need to increase the heating equipment, waste of energy and increase costs, in the case of a vacuum, this temperature range to ensure the efficiency of desorption), desorption time is set to 15 ~ 20min, vacuum chestnut vacuum 0.002 ~ -0.88MPa (absolute pressure); to ensure the condensation effect and to minimize energy, control the pre-cooling temperature: 4 ~ 7 ° C, the first condensing temperature -28 ~ -32 ° C, secondary condensing temperature -68 ~ -72 CC ο

[0025] Comparison of a single use of condensation or a single adsorption method, the use of a single condensation method to recover VOCs oil and gas, only in the condensation temperature of -100 ° (: above conditions can get higher recovery, such as a single adsorption method, Due to the high concentration of VOCs, the life of the adsorbent is very short, the regeneration is frequent, and the adsorption heats up, the adsorption at high concentration, the temperature rises too fast, and there is a certain safety hazard, the invention utilizes the advantages of the condensation method and the adsorption method Optimize the combination, to reduce energy consumption, eliminate security risks and other purposes.

[0026] The above is only a specific embodiment of the present invention, but the design concept of the present invention is not limited thereto, and any non-substantial modification of the present invention by means of this idea is an infringement of the scope of the present invention.