Seek expert advice——can negative-pressure, low-temperature steam be converted into high-pressure, high-temperature steam for use in heat exchangers?
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Experts, I’ve recently run into a rather tricky problem. One of my clients has a system that generates negative pressure, which results in the production of some steam at a temperature below 100 degrees. The client wants to recover this steam for reuse, but they don’t have any equipment designed to handle steam at low temperatures under negative pressure. I have a question: can negative-pressure, low-temperature steam at below 100 degrees be converted into high-pressure, high-temperature steam at 140 degrees using pressure-boosting equipment for use in heat exchangers? Does negative-pressure steam condense into liquid water during the process of being converted into high-pressure steam? I can’t figure this problem out for the time being; I hope experts can offer some guidance.
There’s no need to think about it – it will definitely turn into water. Compression and heating don’t have as much effect as you think
But I have a question that I’m not quite sure about: steam at 90 degrees exists under negative pressure. So, should steam at normal pressure be at 100 degrees? During the positive pressure phase, the temperature will be above 100 degrees. In this process, I used a single-screw compressor to compress the steam. It consumes electrical power. The software calculates that this portion of steam should be compressed into superheated steam. Cooling water is also needed for cooling, and 160 kilograms of such water must be added. It should always be in a pressurized state; shouldn’t the steam not condense?
Don’t even think about doing something that’s obviously a loss – the costs outweigh the benefits.
The last edit to this post was made by Rely on oneself in everything_LWTF on 2019-6-14 at 11:12. Basically, the cost of electricity alone for producing one ton of low-pressure steam is around 130 yuan, and this amount of energy can be used to generate 1.16 tons of high-pressure steam. The basic price of steam from pipeline networks is around 200 yuan per ton. The equipment cost is a bit higher. Economic benefits, if considered in the long term. It is beneficial for enterprises; however, in the short term it is not suitable due to the high cost of equipment.
I don’t know what you used to do the calculations with, but there must be something wrong. You convert electrical energy into mechanical energy, which is then converted into internal energy; there’s also excess heat. I haven’t done the calculations in detail, but if that’s really how you proceed, it seems almost possible to create a perpetual motion machine – steam generates electricity, and that electricity then drives the compressor. . . . .
Steam calculation software provided by compressor manufacturers. It was previously used to calculate positive-pressure steam with great accuracy, but negative pressure has never been calculated before; by using it to do the calculation, these results were obtained. Because the compressor needs to be cooled and lubricated during the compression process, it generates a lot of heat while doing work, and it is this heat that heats the steam until it becomes superheated steam. Therefore, it is necessary to add water and cool down, which causes this water to turn into steam
After careful consideration, it turns out that this is indeed the principle behind heat pump distillation these days, but the temperature increase is usually not that high. When you raise the temperature from 90°C to 140°C, the steam pressure increases several times over.
The principle should be fine; it mainly depends on whether it is cost-effective. If the amount of steam is indeed very large, it is likely worthwhile to recover it.
Advances in the application of mechanical vapor recompression – MVR – heat pump technology – Baidu Wenku: https://wenku.baidu.com/view/378372cd4b73f242326c5fe6.html. You can take a look at this article, which covers the practical use of this technology in industry.
Yeah, thank you very much. Raising the temperature by 50 degrees and increasing the pressure from -0.1 Mpa to 0.3 Mpa results in excessive power consumption; however, if it’s feasible, it could have practical value in the long term. The link has been received, thank you very much