120- Design of a specialized vane separator for inter-stage separation in a reciprocating hydrogen compression unit of a hydrogenation catalytic unit
Thread Content
This post was last edited by luoli519 on 2024-4-1 10:16. In hydrocracking units, multi-stage reciprocating compressors are often used to increase the pressure of the recycle hydrogen in multiple stages. Between each stage of compression units, an efficient vane-type gas-liquid separator must be installed as an inter-stage separator to remove liquefied droplets and foam from the hydrogen gas stream after compression at each stage, thereby preventing damage to the compressor caused by liquid slugs. Here, we will take as an example a specialized vane-type high-efficiency gas-liquid separator designed for inter-stage separation in the reciprocating hydrogen compressor units of a hydrocracking unit owned by CNPC, provided by a company specializing in dynamic gas-liquid separation technologies, and discuss it together. I also hope that everyone will provide additional discussions based on their own experience in the application of inter-stage separators in cyclic compression units.
A hydrocracking unit of CNPC uses a hydrogen circulation compressor unit K-102 supplied by a renowned American compressor manufacturer, while a specialized dynamics separation technology company designed and provided special vane-type gas-liquid separators for the separation between various stages of this compressor unit. This unit compresses recycled hydrogen and is designed and arranged in 3 identical systems A/B/C, operating in a 2-active-1-redundant configuration with each series running at 50%*2 capacity.
The recycle hydrogen compressor units used in each series employ 3-stage compression. Thus, the inter-stage dedicated vane gas-liquid separators consist of three sets of vane gas-liquid separators, namely 1-DISS, which serves as the separator between the first-stage compressor and the second-stage compressor, and three sets of 2-DISS separators, which serve as the separators between the second-stage compressor and the third-stage compressor; in total, there are 6 such vane gas-liquid separators.
The basic operating parameter values for the 1-DISS inter-stage gas-liquid separator provided by the owner are as follows: 1. Medium: hydrogen； 2. Gas phase composition (mol%): H2, 99.90 ； CH4, 010 ； 3. Gas flow rate: 129072.2 Nm^3/h; 4. Operating temperature: 42℃ ； 5. Operating pressure: 4838.4 kPaA.
The basic operating parameter values for the 1-DISS inter-stage gas-liquid separator provided by the owner are as follows: 1. Medium: hydrogen； 2. Gas phase composition (mol%): H2, 99.90 ； CH4, 010 ； 3. Gas flow rate: 129072.2 Nm^3/h; 4. Operating temperature: 42℃ ； 5. Operating pressure: 4838.4 kPaA.
The basic operating parameter values for the 1-DISS inter-stage gas-liquid separator provided by the owner are as follows: 1. Medium: hydrogen； 2. Gas phase composition (mol%): H2, 99.90 ； CH4, 010 ； 3. Gas flow rate: 129072.2 Nm^3/h; 4. Operating temperature: 42℃ ； 5. Operating pressure: 4838.4 kPaA.
This post was last edited by luoli519 on 2017-12-18 at 12:06. The basic operating parameters for the 2-DISS inter-stage gas-liquid separator are as follows: 1. Medium: hydrogen； 2. Gas phase composition (mol%): H2, 99.90 ； CH4, 0.10 ； 3. Gas flow rate: 129069.8 Nm^3/h; 4. Operating temperature: 42℃ ； 5. Operating pressure: 9553.06 kPaA.
The owner and the design institute CEI have the following requirements for the aforementioned inter-stage separator: 1. Use a vertical vane-type high-efficiency gas-liquid separator； 2. Material requirements: Shell, Q345R; Internal components, SS ； 3. Separation efficiency: 99.9% in separating and removing liquid droplets and bubbles with sizes of 5–8 microns and larger ； 4. Operating pressure drop: Not more than 3% of the operating condition pressure.
In response to the technical requirements put forward by the client and CEI regarding inter-stage separators for hydrogen compressors, a specialized company in dynamic gas-liquid separation technology has developed the following technical details for the 1-DISS high-efficiency gas-liquid separator of inter-stage type: 1. Separator type: G50 type vane-type high-efficiency gas-liquid separator； II. Material: Housing, Q345R ； Internal parts, SS304L ； III. Inlet separation assembly: G50B type radiation-stable vane separation assembly ； IV. Precision separation internal component set: G50 type high-efficiency vane gas-liquid separation patented technology internal component set ； V. Equipment dimensions: ID 600 mm x SM/SM 1346 mm; VI. Separation efficiency: 4N level of separation, capable of removing liquid droplets and bubbles with a size of 4.59 microns or larger ； VII. Maximum operating pressure drop: 0.134psi ； VIII. Operational flexibility: 15%-135%.
What I’ve always found confusing is why there is no water in the gas mixture, yet a separator is needed between stages; will hydrogen and methane liquefy after cooling?
From the perspective of the hydrogenation catalytic unit process, the gas-phase analysis clearly provides only partial results, as there are other hydrocarbons present. Methane and other light hydrocarbons with unknown components are liquefied under pressure.