Low Pressure Steam |
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◈ Value Added on Low Pressure Steam |
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When high temperature water delivered from high pressure unit opeartions like reactor in petrochmical plants is adiabatically flashed in low pressure, the low pressure steam is obtained.
If this low pressure steam could be compressed and sold to the neighbouring plant, an investment to MVR system should be economically feasible. But, the most of petrochemical processes are designed to use high pressure steam, there might be less chance except space heating in winter. |
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Thus in summer, the more low pressure steam is exhausted to the air than in winter. If this exhaust can be used to support bottle necked compressor or cooling tower, it will turn out profitable energy.
The following case study may stimulate some petrochemical plants to consider an investment.
2-stage vacuum flash cooling system is designed to utilize 20 ton/h low pressure steam (3 ㎏/㎠G) and 2 units of condenser with each 900 ㎡ heat exchange surface. By optimizing this preconditioned inquiry, we could acquire 4 MW chilling load with saving of approximately US$250,000 per month.
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Descriptions |
Unit |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
Mass Flow |
kg/h |
570,000 |
564,276 |
19,497 |
2,736 |
1,500,000 |
1,500,000 |
1,500,000 |
Pressure |
㎏/㎠G |
2 |
-0.990 |
3 |
-0.993 |
2 |
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Temperature |
℃ |
12 |
6 |
143 |
9 |
30 |
34.5 |
40 |
Specific heat |
kj/kg℃ |
4.250 |
4.333 |
4.217 |
4.222 |
4.167 |
4.174 |
4.175 |
Specific entahlpy |
kj/kg |
2,524 |
2,513 |
2,737 |
2,518 |
2,556 |
2,564 |
2,574 |
Latent heat |
kj/kg |
2,473 |
2,487 |
2,134 |
2,480 |
2,431 |
2,420 |
2,407 |
Enthalpy |
Mj/h |
29,070 |
14,671 |
11,757 |
104 |
187,500 |
216,000 |
250,500 |
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