Thermal Specifics :
The function of this tubular exchanger is to cool humid air in a more general gas production process. Indeed, the customer acquired an “air compressor after cooler” for a production site located in Brazil, following an agreement with a local cellulose and paper production company, for the supply of 160 tons per day of gaseous oxygen. As part of this contract, our client is building a new Air Separation Unit (ASU). The ASU also produces liquid oxygen, nitrogen and argon to serve the region’s mining, iron and steel industries, as well as the healthcare sector.
Nitrogen and oxygen are produced from the air around us in a multi-step process. A first step is to clear the air of dust and begin the compression process. This is followed by a filtration phase to remove carbon dioxide and water before moving on to the cryogenic stage, to liquefy the mixture before distillation and thus obtain gas separation.
The gas cooler that we have designed and manufactured is located at the beginning of the process and its thermal program is to cool the compressed air and to start the extraction of water from the gas.
The so-called “normal” design case consists of cooling 34751Nm3/h (flow rate considered dry, i.e. 12.405 kg/s) of air at 9.4% relative humidity from 115 °C to 35 °C. To achieve this, 94503 kg/h (25.26 kg/s) of water at 30°C is available. The water outlet temperature must not be higher than 40°C and the pressure drop across the exchanger must not exceed 1 bar. For humid air, subjected to a pressure of 21.5 bar a at the exchanger inlet, the total pressure drop must not exceed 0.1 bar.
Some Technical Data :
| Shell side | Tube side | ||
| Thermal program | Fluid name | Cooling water | Wet air |
| Total flow rate kg/s | 25.26 | 12,47 | |
| Gas kg/s | 0,0575 | ||
| Liquid kg/s | 25.26 | ||
| Non condensable kg/s | 12,405 | ||
| Temperature inlet/outlet °C | 30 / 40 | 115 / 35 | |
| Duty kW | 1125.2 | ||
| Contraintes | Fouling m²K /w | 0,00017 | 0,000086 |
| Maxi pressure drop bar | 1 | 0,1 | |
| Maximal overall length m | 7 m | ||
| Nominal diameter inlet / outlet mm | 150 / 150 | 300 / 300 | |
| Tubes diam and thickness mm x mm | 16 x 1,25 | ||
| Tubes material | CuNi 90/10 | ||
| TEMA type | BEM | ||
| N of passes | 1 passe | ||
| Heat exchange area m² | 170.4 | ||
Geometrical specificities :
Horizontal tubular heat exchanger, perfect counterflow
Constructive Specificities :
Code : ASME VIII div 1
Regulation: DESP 97/23/EC
Design temperature: 80°C / +150 °C
Design pressures: 6 / 24 bar (g) on channel side and shell side
Test pressures: 9 / 36bar (g on channel side and shell side.
Welding coefficient 0.85
Material :
| grade | standard | |
| shell | P265 GH | EN 10028-2 |
| Tubesheet | C63000 | ASTM B 171 |
| Channel flanges | P265 GH | EN 10028-2 |
| dishes | P265 GH | EN 10028-2 |
| Bundle tubes | CuNi90/10 | |
| nozzles | Gr6 | ASTM A333 |
| baffles | Brass |
Tube to tubesheet attachment : welded and expanded
Welding processes: EN 288.3 approved
Welders’ approvals: According to EN 287.1
Semi-automatic MIG/MAG processes
Quality Specificities :
LOFC according to customer and local specifications.
Helium inter-circuit leakage test.
Operating file in English and Portuguese language
Vue 3D :
