CN-121988144-A - Acid gas dehydration device and method

CN121988144ACN 121988144 ACN121988144 ACN 121988144ACN-121988144-A

Abstract

The invention relates to an acid gas dehydration device and method. The device comprises a pre-pressurizing unit, a first separator, a heat exchanger, a second separator, a mixing device, a third separator, a multistage pressurizing unit and a Joule-Thomson throttling expansion valve, wherein the pre-pressurizing unit is used for pressurizing and cooling the introduced acid gas feed gas, the first separator is used for removing free water in an acid gas stream, the heat exchanger is used for exchanging heat between the dehydrated acid gas stream and a refrigerant stream at a fourth temperature to obtain a heated refrigerant stream and an acid gas stream at a second temperature, the second separator is used for removing free water in the cooled acid gas stream, the mixing device is used for mixing the refrigerant stream after heat exchange and the dehydrated acid gas stream to obtain a gas stream after mixing at the third temperature, the third separator is used for removing free water in the mixed gas stream, the multistage pressurizing unit is used for pressurizing the introduced separated acid gas stream to obtain a supercritical stream, and the Joule-Thomson throttling expansion valve is used for throttling and expanding the returned supercritical stream at the fourth temperature to obtain the refrigerant stream at the fourth temperature.

Inventors

Chen Siding
ZHANG ZHE
ZENG LUXUAN
LIU YINGMING
HUANG JIAN
WANG CHUNYAN

Assignees

中国石油天然气股份有限公司

Dates

Publication Date: 20260508
Application Date: 20241104

Claims (10)

1. The acid gas dehydration device is characterized by comprising a pre-pressurizing unit, a first separator, a heat exchanger, a second separator, mixing equipment, a third separator, a multi-stage pressurizing unit and a Joule-Thomson throttling expansion valve; The pre-pressurizing unit, the first separator, the heat exchanger, the second separator, the mixing equipment, the third separator, the multi-stage pressurizing unit and the Joule-Thomson throttling expansion valve are sequentially connected; The heat exchanger is connected with the mixing equipment, and the Joule-Thomson throttling expansion valve is connected with the heat exchanger; the pre-pressurizing unit is used for pressurizing the introduced acid gas raw gas, cooling the pressurized acid gas raw gas to a first preset pressure and a first temperature, and introducing the pressurized acid gas raw gas into the first separator; the first separator is used for removing free water in the acid gas phase stream to obtain a dehydrated acid gas phase stream, and the dehydrated acid gas phase stream is introduced into the heat exchanger; The heat exchanger is used for exchanging heat between the dehydrated acidic gas-phase material flow and the introduced refrigeration material flow at the fourth temperature to obtain a warmed refrigeration material flow and a cooled acidic gas-phase material flow at the second temperature, and the warmed refrigeration material flow and the cooled acidic gas-phase material flow are respectively introduced into the second separator; The second separator is used for removing free water in the cooled acid gas phase stream to obtain a dehydrated acid gas phase stream, and introducing the dehydrated acid gas phase stream into the mixing equipment; The mixing equipment is used for mixing the refrigerating material flow subjected to heat exchange and temperature rise with the dehydrated acid gas phase material flow to obtain a mixed acid gas phase material flow at a third temperature, and introducing the mixed acid gas phase material flow into the third separator; The third separator is used for removing free water in the mixed acid gas phase stream to obtain a separated acid gas phase stream, and the separated acid gas phase stream is introduced into the multistage supercharging unit; The multistage pressurizing unit is used for pressurizing the introduced separated acidic gas phase stream and then cooling the pressurized acidic gas phase stream to a second preset pressure and the first temperature to obtain a supercritical state stream, dividing the supercritical state stream into two streams, wherein one stream is used as an output product, and the other stream flows back to the Joule-Thomson throttling expansion valve; The Joule-Thomson throttling expansion valve is used for throttling expansion of a returned supercritical state stream to obtain a refrigeration stream at a fourth temperature and introducing the refrigeration stream into the heat exchanger, wherein the first temperature is higher than the second temperature and higher than the fourth temperature and higher than the third temperature, and the first preset pressure is lower than the second preset pressure.
2. The acid gas dehydration apparatus of claim 1 wherein said pre-booster unit comprises a pre-booster compressor and a pre-booster compressor post-air cooler connected; the pre-pressurizing compressor is used for pressurizing the acid gas raw material gas with the preset inlet pressure which is introduced according to the preset flow to the first preset pressure; The pre-pressurizing compressor rear air cooler is used for cooling the pressurized acid gas to a first temperature and introducing the acid gas into the first separator, wherein the first preset pressure is larger than the preset inbound pressure.
3. The acid gas dehydration apparatus of claim 1, further comprising determining the magnitude of said fourth temperature by: Determining a first generation temperature of a hydrate under the condition of pressure after throttling expansion of the Joule-Thomson throttling expansion valve according to pressure parameters before and after throttling expansion of the Joule-Thomson throttling expansion valve and a pre-established acid gas hydrate prediction fitting model with strong correlation between temperature and pressure; determining the fourth temperature according to the first generation temperature of the hydrate, wherein the fourth temperature is greater than the second generation temperature of the hydrate.
4. The acid gas dehydration apparatus of claim 3 further comprising determining the magnitude of said second temperature by: Determining a second generation temperature of the hydrate under the pressure condition after heat exchange of the heat exchanger according to a preset heat exchange parameter of the heat exchanger and a pre-established acid gas hydrate prediction fitting model with strong correlation of temperature and pressure; Determining the second temperature according to the second generation temperature of the hydrate, wherein the second temperature is greater than the second generation temperature of the hydrate.
5. The acid gas dehydration apparatus of claim 4, further comprising pre-deriving said pre-constructed temperature and pressure strongly correlated acid gas hydrate predictive fit model by: According to preset saturated water conditions, simulating the contents of carbon dioxide and other components in different acid gases under given initial environmental temperature and pressure conditions by Multiflash software to obtain hydrate generation curves of different acid gases; And fitting according to different hydrate generation curves to obtain a hydrate optimal control point control model, wherein the hydrate optimal control point control model is used as the pre-constructed acid gas hydrate prediction fitting model with strong correlation between temperature and pressure.
6. The acid gas dehydration apparatus of claim 5 further comprising determining the magnitude of said third temperature by: Simulating by Multiflash software according to preset mixing parameters of the mixing equipment to obtain a third generation temperature of the hydrate under the pressure condition after the mixing equipment is mixed; Determining the third temperature according to the third generation temperature of the hydrate, wherein the third temperature is greater than the third generation temperature of the hydrate.
7. The acid gas dehydration apparatus of claim 1 wherein said multi-stage supercharging unit comprises a plurality of supercharging devices connected in sequence; each of the supercharging apparatuses includes a compressor and an air cooler, and the outlet pressures of the compressors in the adjacent supercharging apparatuses are sequentially increased.
8. The acid gas dehydration apparatus of claim 7 wherein said multi-stage supercharging unit comprises a first supercharging device, a second supercharging device, a third supercharging device, and a fourth supercharging device connected; The first pressurizing equipment is used for pressurizing the introduced separated acid gas phase stream, cooling the pressurized acid gas phase stream to a third preset pressure and a first temperature, and introducing the pressurized acid gas phase stream into the second pressurizing equipment; the second pressurizing device is used for pressurizing the introduced separated acid gas phase stream, cooling the pressurized acid gas phase stream to a fourth preset pressure and a first temperature, and introducing the pressurized acid gas phase stream into the third pressurizing device; The third pressurizing device is used for pressurizing the introduced separated acid gas phase stream, cooling the pressurized acid gas phase stream to a fifth preset pressure and a first temperature, and introducing the pressurized acid gas phase stream into the fourth pressurizing device; The fourth pressurizing equipment is used for pressurizing the introduced separated gas-phase material flow and then cooling the gas-phase material flow to a second preset pressure and a first temperature to obtain a supercritical material flow, the second preset pressure is larger than the fifth preset pressure and larger than the fourth preset pressure and larger than the three preset pressures, and the second preset pressure is larger than or equal to 7MPa.
9. The acid gas dehydration apparatus of claim 1 further comprising a diversion device; The split-flow equipment is connected with the multi-stage supercharging unit and is used for dividing the obtained supercritical state flow into two streams, wherein one stream is used as an output product, and the other stream flows back to the Joule-Thomson throttling expansion valve.
10. A method for dehydrating acid gas, comprising: The method comprises the steps of pressurizing the introduced acid gas raw material gas through a pre-pressurizing unit, cooling to a first preset pressure and a first temperature, and introducing the acid gas raw material gas into a first separator; the first separator is used for removing free water in the acid gas phase stream to obtain a dehydrated acid gas phase stream, and the dehydrated acid gas phase stream is introduced into a heat exchanger; the heat exchanger is used for exchanging heat between the dehydrated acidic gas-phase material flow and the introduced refrigeration material flow at the fourth temperature to obtain a warmed refrigeration material flow and a cooled acidic gas-phase material flow at the second temperature, and the warmed refrigeration material flow and the cooled acidic gas-phase material flow are respectively introduced into the second separator; The second separator is used for removing free water in the cooled acid gas-phase material flow to obtain a dehydrated acid gas-phase material flow, and the dehydrated acid gas-phase material flow is introduced into mixing equipment; The mixing equipment is used for mixing the heat-exchanged refrigerating material flow and the dehydrated acid gas-phase material flow to obtain an acid gas-phase material flow mixed at a third temperature, and the acid gas-phase material flow is introduced into a third separator; The third separator is used for removing free water in the mixed acid gas phase stream to obtain a separated acid gas phase stream, and the separated acid gas phase stream is introduced into a multi-stage supercharging unit; The multistage pressurizing unit is used for pressurizing the introduced separated acidic gas phase stream and then cooling the pressurized acidic gas phase stream to a second preset pressure and the first temperature to obtain a supercritical state stream, and dividing the supercritical state stream into two streams, wherein one stream is used as an output product, and the other stream flows back to a Joule-Thomson throttling expansion valve; And throttling expansion is carried out on the returned supercritical state stream through the Joule-Thomson throttling expansion valve to obtain a refrigeration stream at a fourth temperature and introducing the refrigeration stream into the heat exchanger, wherein the first temperature is higher than the second temperature and higher than the fourth temperature and higher than the third temperature, and the first preset pressure is lower than the second preset pressure.

Description

Acid gas dehydration device and method Technical Field The invention relates to an acid gas dehydration device and method. Background Acid gases typically contain a variable amount of moisture (water vapor or free water) that reacts to form acid when dissolved in water. The acid gas with water may cause serious consequences such as corrosion of metal materials or generation of gas hydrate, for example, in the presence of water, natural gas (acid natural gas) containing acid gas may form corrosive acid liquid to corrode pipelines and equipment, and also may significantly raise hydrate generation temperature, so that hydrate is generated even at higher temperature to affect pipeline transportation, and cause valve blockage, pipeline ice blockage and equipment damage to affect safe production. If the acidic natural gas is used as chemical raw material, catalyst poisoning can be caused, and the yield and quality of the product are affected. Therefore, the water content index in acid gases is often tightly controlled as an important index in addition to purity. In the context of positive response to global "two carbon" targets, carbon Capture and Sequestration (CCS) and carbon capture, utilization and sequestration (CCUS) technologies have become the focus of attention in the oil and gas industry. These techniques are significant in reducing greenhouse gas emissions and driving energy conversion. However, both the product gas (high purity CO 2 containing impurities) of the carbon capture unit in CCS/CCUS systems and the feed gas (H 2 S and CO 2) of the acid gas reinjection system are typical acid gases which under aqueous conditions can pose serious threats to critical equipment in oil and gas extraction and processing, leading to equipment corrosion, plugging, and thus affecting the stability and safety of the overall process system. Acid gas dehydration is a process that removes moisture from acid gases to prevent free water precipitation and hydrate formation. The conventional method for inhibiting the hydrate in the acid gas dehydration process mainly comprises the step of adding a hydrate inhibitor such as alcohols, ethers and other organic compounds into fluid, and the method is used for reducing the capability of generating the hydrate by changing the chemical position of an aqueous solution or a hydrate phase, so that the industrial requirement is met to a certain extent. Disclosure of Invention To better achieve acid gas dehydration. The invention provides an acid gas dehydration device and method. The technical scheme provided by the invention is as follows: in a first aspect, the invention provides an acid gas dehydration plant comprising a pre-pressurizing unit, a first separator, a heat exchanger, a second separator, a mixing device, a third separator, a multi-stage pressurizing unit and a Joule-Thomson throttling expansion valve; The pre-pressurizing unit, the first separator, the heat exchanger, the second separator, the mixing equipment, the third separator, the multi-stage pressurizing unit and the Joule-Thomson throttling expansion valve are sequentially connected; The heat exchanger is connected with the mixing equipment, and the Joule-Thomson throttling expansion valve is connected with the heat exchanger; the pre-pressurizing unit is used for pressurizing the introduced acid gas raw gas, cooling the pressurized acid gas raw gas to a first preset pressure and a first temperature, and introducing the pressurized acid gas raw gas into the first separator; the first separator is used for removing free water in the acid gas phase stream to obtain a dehydrated acid gas phase stream, and the dehydrated acid gas phase stream is introduced into the heat exchanger; The heat exchanger is used for exchanging heat between the dehydrated acidic gas-phase material flow and the introduced refrigeration material flow at the fourth temperature to obtain a warmed refrigeration material flow and a cooled acidic gas-phase material flow at the second temperature, and the warmed refrigeration material flow and the cooled acidic gas-phase material flow are respectively introduced into the second separator; The second separator is used for removing free water in the cooled acid gas phase stream to obtain a dehydrated acid gas phase stream, and introducing the dehydrated acid gas phase stream into the mixing equipment; the mixing equipment is used for mixing the heat-exchanged refrigerating material flow and the dehydrated acid gas-phase material flow to obtain a mixed acid gas-phase material flow at a third temperature, and introducing the mixed acid gas-phase material flow into the third separator; The third separator is used for removing free water in the mixed acid gas phase stream to obtain a separated acid gas phase stream, and the separated acid gas phase stream is introduced into the multistage supercharging unit; The multistage pressurizing unit is used for pressurizing the introduced separated acidic gas ph